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REPORT ON

STRUCTURAL ASSESSMENT & SEISMIC EVALUATION OF THE

MOUNT SAN ANTONIO COLLEGE TECHNOLOGY CENTER BUILDING 28A-B

PREPARED FOR

MOUNT SAN ANTONIO COLLEGE 1100 N. Grand Avenue

Walnut, CA 91789-1341

BY

ssssssss IDS GROUP, INC. INTEGRATED DESIGN SERVICES

1 Peters Canyon Rd., Suite 140, Irvine, CA 92606

IDS Project Number 28.122

May 2008

Mount San Antonio College Seismic Assessment of Mt. SAC Technology Center Building 28A-B

May 2008

of 57 ssssssss IDS GROUP, INC. INTEGRATED DESIGN SERVICES

TABLE OF CONTENTS Page

I. EXECUTIVE SUMMARY........................................................................................... 3

II. INTRODUCTION......................................................................................................... 5

Background............................................................................................................. 5

Purpose ................................................................................................................... 6

Scope....................................................................................................................... 6

Limitations.............................................................................................................. 6

III. REFERENCES.............................................................................................................. 7

IV. BUILDING DESCRIPTION......................................................................................... 8

General Description ...................................................................................................... 8

Structural Systems......................................................................................................... 8

V. SEISMIC EVALUATION ........................................................................................... 11

Seismic Hazards ........................................................................................................... 11

Seismic Activity Near the Campus .............................................................................. 14

ASCE 31 Tier 1 Evaluation Results............................................................................. 16

Seismic Performance.................................................................................................... 18

VI. SITE OBSERVATIONS & PHOTOS.......................................................................... 24

VII. FINDINGS & RECOMMENDATIONS...................................................................... 29

Possible Retrofit Concepts ........................................................................................... 29

Opinion of Probable Cost ............................................................................................ 30

Recommended Next Steps............................................................................................ 32

APPENDICES

A – Conceptual Seismic Retrofit Sketches............................................................ 32

B – ASCE Tier 1 Evaluation Checklists................................................................ 35


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STRUCTURAL ASSESSMENT & SEISMIC EVALUATION OF THE MOUNT SAN ANTONIO COLLEGE

TECHNOLOGY CENTER BUILDING 28A-B

I. EXECUTIVE SUMMARY:

This report presents the results of the structural assessment of the seismic risk to the Technology Center Building 28A-B complex at Mount San Antonio College (Mt. SAC) in Walnut, California. The total complex of buildings, including the Technology Center Building 28B, the Shops Building 28A, the Lecture Hall & Administration area, and the Test Cells area contain a total floor area of approximately 111,000 square feet. The facility was designed circa 1968, and construction completion was in early 1971.

The seismic risk assessment is based on an ASCE 31 Tier 1 vulnerability analysis conducted via checklists of critical structural items for each type of structure in this four-building complex, in conjunction with a review of original design drawings and assessment of potential damage areas based on experience and judgment concerning the performance of this type of structure in past major earthquakes. ASCE 31 is a national document widely used for the seismic assessment of building structures as adopted by DSA for building assessment. Regional seismic hazards were also investigated in this report. It was found that the Mt. SAC site is located within 4 miles of the Elsinore fault zone, which is capable of a magnitude 6.5+ event. Numerous other fault zones capable of causing strong ground shaking are located within close proximity to the Mt. SAC campus. It does not appear that liquefaction, landslide, ground rupture and other soils effects are likely to occur at this site.

Based on the ASCE 31 Tier 1 and limited Tier 2 analyses, and review of original structural design drawings, we find the following areas of potential damage and associated proposed retrofit measures for each key building within the Technology Center Building 28A-B complex are required in order to bring the facilities into conformance with DSA’s “Enhanced Life Safety” performance goals for community college facilities that house classrooms and student activities:

• Classroom Building 28B: This building can experience significant damage to the bottom tow stories of the brick masonry shear walls on the north and south sides, and damage to the interior columns due to sway of the floor levels and vertical shocks similar to those experienced by many buildings in the 1994 Northridge earthquake. A 6” layer of reinforced shotcrete will strengthen the brick masonry shearwalls, and multiple layers of fiber reinforced polymer will protect the columns from significant damage.

• Shops Building 28A: The Shops Building can experience damage due to pounding with the adjacent Classroom Building. Severe structural damage up to and including collapse can also occur if the flexible roof separates from the roof girder support pilasters and exterior walls, which has been observed in similar past quakes. An allowance has been made to provide for expanding the too-narrow separation joint that already exists between the Shops Building and Classroom Building, and new anchors can be attached to the main roof support


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girders and bolted through the exterior walls to prevent the roof system from separating from the exterior walls.

• Lecture Hall & Administration Building: This building has seismic deficiencies similar to those of the Shops Building. An allowance has been made to expand the narrow separation joint between the Lecture Hall and the Shops building, and the roof beam support points at the exterior wall pilasters can be strengthened in a manner similar to that for the Shops Building.

• Test Cells Building: This building was found to be of such rugged cast-in-place concrete construction that no retrofit measures appear warranted to assure that the building’s seismic performance is consistent with the Enhanced Life Safety performance category.

Our opinion of the probable cost to implement the above recommendation as further described in this report is $1,200,000. This cost covers structural upgrade only, including an allowance for major equipment anchorage, with the assumption that the building will be closed during construction, thus allowing for uninhibited access to perform the structural work. The additional costs for related architectural modifications, new facility renovations, ADA compliance, fire and life safety improvements and access modifications are not included in this opinion of probable cost.

Note that planned renovations to the facility have been reviewed in the form of preliminary architectural sketches depicting new room layouts and functions. The purpose of this review was to make a preliminary assessment of the feasibility of the planned work in light of the seismic risk to the facilities and the proposed retrofit measures. In this regard, we find that the planned architectural renovations appear feasible; however, the addition of new openings in the exterior walls of the Classroom Building 28B could trigger the need for extensive new shotcrete applied to the exterior walls. Depending on the extent of desired wall openings, such additional shotcrete work could add several hundred thousand dollars in cost.

We recommend that the next step in the evaluation process include a detailed structural analysis of the facilities based on ASCE 31 Tier 2 or 3 requirements, confirmation of the extent of required retrofits in order to correct identified deficiencies, development of workable and cost-effective retrofits that are compatible with the future planned architecture of the building, and a more in-depth cost estimate that can be used for budgeting.


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II. INTRODUCTION:

Background:

The Mt. San Antonio College (SAC) Technology Center Building 28A-B is located at Mount San Antonio College at 1100 N. Grand Avenue, Walnut, California, 91789-1341. This “building” is actually a complex of four structurally independent buildings of widely varying size, construction type and function – see the figure below. The four buildings are as follows, using the original building names indicated on the record drawings (Reference 2, see Section III below):

• Classroom Building (presently identified as Building 28B): Four stories, reinforced concrete with concrete and masonry walls, approximately 75,000 square feet.

• Shops Building (presently identified as Building 28A): One story high bay with narrow interior mezzanine on three sides, steel frame roof with perimeter concrete and masonry walls, approximately 26,000 square feet in plan.

• Lecture Hall & Administration Wing: One story with two separate wings and a common steel framed roof with metal deck, perimeter 9” thick brick masonry walls, approximately 6,000 square feet.

• Test Cells: One story, cast-in-place reinforced concrete floors, walls (interior and exterior) and roof, approximately 3,600 square feet.

Technology Center Building 28A-B Complex


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Purpose:

This report summarizes the results of site observations, drawing reviews, and preliminary projections of structural performance during a major earthquake based on engineering judgment in conjunction with ASCE 31, Tier 1 seismic evaluation checklists. ASCE 31 is a national document widely used for the seismic assessment of building structures as adopted by DSA for building assessment. The report includes a summary of project results, as well as findings, recommendations, preliminary costs for seismic retrofit, and recommended next steps.

Scope:

The project scope of provided services is as follows:

1. Review available structural and architectural drawings and visit the project site.

2. Perform an ASCE 31 (FEMA 310) Tier 1 evaluation of Technology Center Building 28A-B.

3. Determine the regional seismic hazard and assess the potential for structural damage.

4. Prepare a summary report with strengthening recommendations, preliminary retrofit sketches, and an opinion of probable cost for the retrofit construction.

Limitations:

This report is based on a site visit, review of available drawings and structural screening and preliminary evaluation based on judgment and experience. This assessment is based on the assumption that the buildings were constructed in accordance with the available existing drawings and that elements used to resist lateral forces are in good condition. Our investigation was limited to the visual observation of items not covered by finish material. Other conditions affecting the structure that were not inspected, anticipated, or accessible are beyond the scope of this report.

This assessment is limited to the buildings’ primary structural systems. Evaluation of nonstructural items such as architectural elements, furnishings and interior equipment, and electrical, mechanical, and plumbing systems are not considered in this evaluation. The findings presented in this report are for the sole use of Mount San Antonio College in its evaluation of the seismic performance of the subject buildings, and are not intended for use by other parties, and may not contain sufficient information for purposes of other parties or other uses. Our professional services have been performed with the degree of care and skill ordinarily exercised, under similar circumstances, by reputable consultants practicing in this field at this time.


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III. REFERENCES:

The following references were used in the evaluation of this building:

1. American Society of Civil Engineers; “ASCE/SEI 31-03, Seismic Evaluation of Existing Buildings.”

2. As-built architectural drawing sheets A, A-11 through A-17, A-24 through A-28, A-32, A-37 through A-39 and as-built structural drawing sheets S 6 through S 18 by Austin Field & Fry Architects & Engineers, and Wheeler & Gray Consulting Engineers, dated April 23, 1971, and stamped by the California Department of General Services, Office of Architecture and Construction, on October 9, 1968.

3. “Geologic and Geotechnical Investigation Report, Proposed Math and Science Building, Mount San Antonio College, Walnut, California,” Converse Project No. 06-31-109-01, Converse Consultants, February 17, 2006.

4. “Geotechnical Investigation, Seismic Retrofit – Building 45, Mount San Antonio College, Walnut, California,” Project 2494-04, Global Geo-Engineering, August 22, 2006.

5. International Conference of Building Officials: “Maps of Known Active Fault Near-Source Zones in California and Adjacent Portions of Nevada,” February 1998.

6. City of Walnut General Plan: http://ci.walnut.ca.us/upload/WalnutGP2.pdf

7. State of California Division of Mines and Geology, “Seismic Hazard Zones Map –San Dimas Quadrangle”, released March 25, 1999. http://gmw.consrv.ca.gov/shmp/download/pdf/ozn_sdim.pdf

8. SCEC Faults of Southern California: http://www.data.scec.org/faults/lafault.html

9. Southern California Earthquake Data Center (SCEC): http://www.data.scec.org/index.html

10. The Working Group on California Earthquake Probabilities (WGCEP) “Appendix A – 2002 California Fault Parameters”, http://wgcep.org/.

11. USGS, Intensity Map for Whittier Earthquake: http://earthquake.usgs.gov/eqcenter/shakemap/sc/shake/Whittier_Narrows/

12. USGS, Intensity Map for Northridge Earthquake: http://earthquake.usgs.gov/eqcenter/shakemap/sc/shake/Northridge/

13. United State Geological Survey; “Seismic Hazard Curves, Response Parameters and Design Parameters” online calculator, , Version 5.0.8: http://earthquake.usgs.gov/research/hazmaps/design/index.php

14. Center for Engineering Strong Motion Data (CESMD), “Combined Strong-Motion Data – M6.1 Whittier Earthquake of 01 Oct 1987”: http://www.strongmotioncenter.org/cgi-bin/ncesmd/Multiplesearch_eq_D.pl?staID=%&statype=%&material=Any&height=%&PMix=-10000&PMax=3&DMix=0&DMax=1000&SFlag=&iqrid=Whittier87


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15. Center for Engineering Strong Motion Data (CESMD), “Combined Strong-Motion Data – M6.4 Northridge Earthquake of 17 Jan 1994”: http://www.strongmotioncenter.org/cgi-bin/ncesmd/Multiplesearch_eq_D.pl?staID=%&statype=%&material=Any&height=%&PMix=-10000&PMax=3&DMix=0&DMax=1000&SFlag=&iqrid=Northridge_17Jan1994

IV. BUILDING DESCRIPTION:

General Description:

The Technology Center Building 28A-B at Mt. SAC consists of the following four structures:

• Classroom Building (presently identified as Building 28B): Building 28B has four stories over a single-level basement with reinforced structural slab and pan joist floors and roof, concrete columns, and exterior concrete and masonry walls. It has plan dimensions of approximately 111’ by 156’ and contains approximately 75,000 square feet. This and the other buildings indicated below appear on the same set of record drawings (Reference 2) and were approved for construction in 1968. The “AS-BUILT” drawing set is dated April 23, 1971.

• Shops Building (presently identified as Building 28A): Building 28A is a one story high bay structure with a steel frame and a 2-1/2” thick insulating gypsum roof deck with bulb tees, enclosed by reinforced concrete and masonry perimeter walls. It also has a wood framed interior mezzanine on three sides that houses offices and classrooms. The overall floor plan is approximately 123’ by 210’, with square feet in plan.

• Lecture Hall & Administration Wing: This structure involves two separate building areas under a single roof. The Lecture Hall is about 66’ by 59’ in plan, and has a stepped concrete floor system with attached amphitheater-style seating. It has 9” brick walls on the perimeter, and an 8” CMU wall at the lecture hall entrance which is set back about 14’ from the front of the building. The Administration Wing is about 50’ by 37’ in plan, and has 9” brick walls on the perimeter. Both building areas are under a common steel framed roof with a 1-1/2” deep by 20 gage metal deck roof.

• Test Cells: This structure is entirely of reinforced concrete, and consists of a matrix of small rooms that contain various test functions. The plan dimensions are approximately 62’ by 58’. All interior and exterior walls are 8” to 10” thick reinforced concrete walls with a single curtain of rebar, and the roof consists of a 7” thick slab spanning one-way over the interior walls. The northeast 36’ by 20’ section of the building has an 8” thick roof.

Structural Systems:

Technology Building 28B

Vertical Load Carrying System: The basement level floor is a 6” thick slab on grade, and the first through fourth floors and roof consist of a pan joist system composed of a 4½” thick slab over 10” deep joists ranging in width from 5½” to 12”, with a total slab + joist depth of


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1’-2½”. Each joist is uniquely reinforced for the particular zone loading in the building. The pan joist slabs typically span 19’-6” to 24” wide concrete girders ranging in depth from 27” to 30”. The girders then span from 28’-6” to 38’-6” to concrete columns. The interior columns are square in plan with dimensions ranging from 14” at the 4th level to 18” at the ground level. At the basement level, the perimeter concrete walls are 10” to 12” thick in the north-south direction and 10½” thick in the east-west direction. At the upper levels, the perimeter walls are 10” thick concrete walls in the north-south direction and 9” thick brick masonry walls in the east-west direction. The interior columns are supported on 5’-6” wide by 8’-6” long by 3’-7” thick pile caps with 6 piles. The pile type was selected among two options: Raymond Step Tapered piles or, at the Contractor’s option, concrete-filled 12” diameter steel pipes with a wall thickness of 0.281”. Exterior concrete columns are supported by pile groups consisting of varying numbers of piles. On the north side of the building, the basement perimeter concrete walls span to piles in groups of 4, 5 or 6, spaced 19’-6” apart, with a single pile support provided at mid-span. On the south side of the building, the basement perimeter concrete walls span to piles in groups of 4 or 5, spaced 19’-6” apart. On the west side of the building, the basement perimeter concrete walls span roughly 30’-0” to piles in groups of 4, with two single piles spaced at equal distances along the span length; 14” wide grade beams connect the pile caps where the concrete perimeter wall is not continuous. On the east side of the building, the basement perimeter concrete walls span roughly 30’-0” to piles in groups of 4 or 6, with two single piles spaced at equal distances along the span length. Per the pile cap schedule shown on the as-built drawings, 4-pile groups are designed for 410 kips, 5-pile groups are designed for 591 kips, and 6-pile groups are designed for 610 kips. Lateral Load Carrying System: Due to the weight of the building and locale, lateral loads are clearly governed by earthquake forces. Earthquake forces are resisted by the very rigid concrete floor and roof diaphragms which span to exterior walls that support both vertical and lateral loads. The exterior shear walls deliver earthquake forces to the supporting soil system primarily via friction between the extensive basement slab on grade system, friction between the basement walls and backfilled soil, and some passive pressure against the corner zones of the basement walls. It appears the flexural and shear capacity of the piles offer very little lateral resistance relative to the aforementioned systems.

Shops Building 28A

Vertical Load Carrying System: Sheet S-3 from the record drawing set was not available; however, based on the building cross-section view and other buildings within this complex, it appears that the foundation system consists of a 4” slab on grade, which is tied into the perimeter wall footings/pile foundations at each frame line. The roof is steel framed and consists of tapered steel girders (TGs) spaced on 21’ centers spanning half-way in the north-side direction, and are supported by 8”x8” steel tube columns along the centerline of the building. The TGs support 10B11.5 wide flange purlins spaced on 6’-8” centers. The purlins support a design-build roof system composed of bulb-tee joists at 32” to 36” spaces which support a poured-in-place 2-1/2” thick insulating gypsum roof. The perimeter walls on the north, west and south sides are 7-1/2” thick precast concrete panels with pilaster for


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TG support, and the east wall is 10” thick cast-in-place concrete that supports 10B purlins at that end of the building. The Shop Building also contains an interior mezzanine on the south side that is approximately 10’ to 15’ wide and runs between the west end of the building and column line 17, just 42’ short of the east end of the building. The mezzanine is largely constructed of steel posts supporting 12” steel channels at the outer edge, with 2x10 floor joists at 16” spanning between the south building wall and the 12” edge channels. The floor joists support a ¾” thick plywood floor.

Lateral Load Carrying System: The poured gypsum roof deck is primarily for insulation and not used as an element of the lateral load carrying system. Instead, the roof is laced around the perimeter with two bays of 1-1/4” to 1-3/8” diameter rod horizontal X-bracing. The rod bracing is connected to the TG framing and drag lines consisting of heavier wide flange beams (10WF25 to 12WF31) that can handle the axial loads from the braces. The bracing system delivers seismic roof loads to the perimeter walls which act as shear walls to carry the seismic loads to the slab on grade foundation system, which transfers the loads to the soil system. The pile cap and pile system does not offer significant lateral resistance compared to the sliding friction resistance provided by the slab on grade.

Lecture Hall & Administration Wing

Vertical Load Carrying System: Vertical loads are supported by the 1-1/2” by 20 gage metal deck roof, which is supported by structural steel framing. Over the lecture hall area, the steel frame consists of TGs spanning the building width in the north-south direction, which support 8B purlins spaced approximately 6’ on center. Over the administration area, the steel frame consists of two, 3-1/2” diameter steel tube columns centered at 1/3 points in the north-south direction, which support 10” to 12” WF beams. These wide flange beams support 8B15 purlins that span from the walls to the center of the building and are spaced on approximately 7’ centers. The perimeter walls support the roof system with pilasters, and the more heavily loaded pilasters which carry the main girders and beams are supported by pile footings, while the typical wall element that only supports tributary purlin loads is supported by continuous wall footings without pile support.

Lateral Load Carrying System: Lateral loads are resisted by the metal deck diaphragm which transfers loads to the perimeter shear walls via deck welds to bolted channels and angles. The shear walls deliver lateral loads to the ground level soil system through their connection to the slab on grade.

Test Cells

Vertical Load Carrying System: Vertical loads are carried by the 7” thick one-way reinforced concrete roof slab, which spans to 8” to 10” thick interior and exterior bearing walls. The walls are supported by continuous wall footings, and the floor is a 4” thick concrete slab on grade. There are no piles supporting the continuous wall footings.


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Lateral Load Carrying System: Lateral loads are resisted by the rigid concrete roof diaphragm, which carries the loads to the interior and perimeter shear walls, which deliver the loads to the foundation system via the concrete slab on grade.

V. SEISMIC EVALUATION:

Seismic Hazards:

The following is an overview of the key seismic hazards for the Mt. SAC Technology Center Building 28A-B:

Based on the City of Walnut General Plan [Ref. 6], and soils reports for two nearby buildings [Ref’s 3 and 4, for Buildings 61 and 45, respectively] ground shaking is expected to be the most significant and probable seismic hazard to the site. Note that very shallow ground water levels have been recorded in most of the alluviated valley throughout the City of Walnut. Ground water levels could rise fairly close to the surface during the rainy season and the entire Mt. SAC campus is within a potential liquefaction zone [Ref. 7]; however, this condition should not endanger the buildings as both soils reports for nearby facilities [Ref’s 3 and 4] indicate that this area of the campus contains dense and fine clayey materials that are not susceptible to liquefaction under strong ground shaking. Other hazards, such as surface fault rupture, lateral spreading, landslides, differential settlement and erosion, do not pose a significant threat to the Building 28A-B complex in accordance with the aforementioned soils reports.

There are no active or potentially active faults near the campus, which is not located within a currently designated State of California Earthquake Fault Zone. Though many faults surround the campus area, the nearest significant fault is the Central Avenue branch of the Whittier-Elsinore fault zone, which is approximately 4 miles east of the site. Listed below and shown in Figure 1 are several faults of varying significance in terms of potential for causing significant shaking at the Mt. SAC site:

• 0 km (0 mi) San Jose Fault [Ref. 5] • 6 km (4 mi) Elsinore Fault [Ref. 3] • 10 km (6 mi) Sierra Madre Fault [Ref. 5] • 32 km (20 mi) Newport-Inglewood Fault [Ref. 6] • 45 km (28 mi) San Andreas Fault (southern segment) [Ref. 6] • 50 km (31 mi) San Fernando Fault [Ref. 8]


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Figure 1: Vicinity Map of Faults [Ref. 10]

Newport-Inglewood Fault

San Andreas Fault

Sierra Madre Fault

San Jose Fault

1933 Newport– Inglewood (Long Beach) Earthquake – [M 6.4]

Mt. SAC Technology

Ctr Bldg 28A-B

1971 San Fernando (Sylmar) Earthquake – [M 6.6]

San Fernando Fault


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San Jose Fault [Ref. 9] TYPE OF FAULTING: left-lateral strike-slip; minor reverse component possible LENGTH: 20 km LAST SIGNIFICANT QUAKE: February 28, 1990, ML5.4 (no surface rupture) MOST RECENT MAJOR RUPTURE: within the past 700,000 years SLIP RATE: 0.5 mm/yr INTERVAL BETWEEN MAJOR RUPTURES: unknown PROBABLE MAGNITUDES: ML6.0 – 6.5 OTHER NOTES: The fault dips steeply to the north. Elsinore Fault Zone (Central Avenue Branch) [Ref. 3] TYPE OF FAULTING: right-lateral strike-slip LENGTH: about 180 km MOST RECENT SURFACE RUPTURE: estimated 1700s LAST MAJOR RUPTURE: May 15, 1910, M6 SLIP RATE: roughly 4 mm/yr INTERVAL BETWEEN MAJOR RUPTURES: roughly 250 years PROBABLE MAGNITUDES: ML6.5 – 7.5 OTHER NOTES: Recurrence interval given above suggests slip of 1.25 to 1.5 meters per surface rupturing event. The Elsinore fault zone is one of the largest in southern California, and in historical times, has been one of the quietest. The southeastern extension of the Elsinore fault zone, the Laguna Salada fault, ruptured in 1892 in a magnitude 7 quake, but the main trace of the Elsinore fault zone has only seen one historical event greater than magnitude 5.2 -- the earthquake of 1910, a magnitude 6 shock near Temescal Valley, which produced no known surface rupture and did little damage. At its northern end, the Elsinore fault zone splays into two segments, the Chino fault and the Whittier fault. At its southern end, the Elsinore fault is cut by the Yuha Wells fault from what amounts to its southern continuation: the Laguna Salada fault. Several of the fault strands which make up the Elsinore fault zone possess their own names. Northwest of Lake Elsinore are the Glen Ivy North and Glen Ivy South faults. Heading southeast from Lake Elsinore, the two parallel fault strands are the Wildomar fault (the more easterly) and the Willard fault. Sierra Madre Fault Zone [Ref. 9] TYPE OF FAULTING: reverse LENGTH: 75 km total; each of five segments is approximately 15 km MOST RECENT SURFACE RUPTURE: within the past 10,000 years SLIP RATE: 2.0 mm/yr [Ref. 8] INTERVAL BETWEEN SURFACE RUPTURES: several thousand years PROBABLE MAGNITUDES: MW6.0 - 7.0 OTHER NOTES: This was not the fault that produced the 1991 Sierra Madre earthquake, which is named for the community near which it occurred. The Sierra Madre is a complex system of faults


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which is typically divided into five main segments which are themselves comprised of parallel and branching faults. In theory, rupture within this fault zone may occur at only one segment during a seismic event, but recent studies suggest that a large seismic event on the San Andreas fault to the north could result in simultaneous ruptures on reverse faults south of the San Gabriel mountains, which may or may not multiple segments of the Sierra Madre fault zone. Newport-Inglewood Fault Zone [Ref. 9] TYPE OF FAULTING: right-lateral; local reverse slip associated with fault steps LENGTH: 66 km [Ref. 8] MOST RECENT MAJOR RUPTURE: March 10, 1933, MW6.4 (no surface rupture) SLIP RATE: 1.0 mm/yr [Ref. 8] INTERVAL BETWEEN MAJOR RUPTURES: unknown PROBABLE MAGNITUDES: MW6.0 - 7.4 OTHER NOTES: Surface trace is discontinuous in the Los Angeles Basin, but the fault zone can easily be noted there by the existence of a chain of low hills extending from Culver City to Signal Hill. South of Signal Hill, it roughly parallels the coastline until just south of Newport Bay, where it heads offshore, and becomes the Newport-Inglewood - Rose Canyon fault zone. San Fernando Fault Zone [Ref. 9] TYPE OF FAULTING: thrust LENGTH: 17 km MOST RECENT MAJOR RUPTURE: February 17. 1971; MW6.6 SLIP RATE: 2.0 mm/yr [Ref. 8] INTERVAL BETWEEN MAJOR RUPTURES: roughly 200 years PROBABLE MAGNITUDES: MW6.0 – 6.8 OTHER NOTES: Dip is to the north. The slip rate is not well known, but trenching studies indicate recurrence interval as between 100 and 300 years. The San Fernando fault is also identified in some publications as the ‘Sierra Madre (San Fernando)’ fault. San Andreas Fault Zone [Ref. 9] TYPE OF FAULTING: right-lateral strike-slip LENGTH: 550 km for the southern (Mojave) segment LAST MAJOR RUPTURE: January 9, 1857 SLIP RATE: 24.0 to 34.0 mm/yr INTERVAL BETWEEN MAJOR RUPTURES: average of 140 years on the southern segment PROBABLE MAGNITUDES: MW6.8 – 8.0 OTHER NOTES: The San Andreas is perhaps California’s most significant fault zones, extending from south of the Salton Sea through Central California and off the coast north of San Francisco. Scientists consider this fault as a series of individual fault segments. The southern series of these segments are most likely to affect the college site. Seismic Activity Near the Campus:

Seismic intensity is a measure of the ground motion felt during a seismic event. Intensity depends on proximity to the source, soil conditions and other factors. Accelerographs, which measure ground


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shaking, have been installed by the California Geological Survey throughout the state, from which vital information such as seismic intensity is obtained during seismic events. Shakemaps illustrate these recorded ground motions. Figures 2 and 3 below show the perceived ground shaking and estimated peak ground acceleration for two relatively recent earthquakes, the 1987 Whittier Narrows earthquake and the 1994 Northridge earthquake. During the Whittier Narrows earthquake, nearby recording stations recorded a peak ground acceleration of 0.07 g [Ref. 14]. During the Northridge earthquake, the same station recorded a peak ground acceleration of 0.05 g [Ref. 15]. It is also noted that based on perceived shaking intensity (as measured by the Mercalli scale), Figures 2 and 3 both show that the campus likely experienced moderate shaking during these earthquakes.

Figure 2: Seismic Intensity Map for the Whittier Narrows Earthquake, October 1987 [Ref. 13]

Mt. SAC Technology Center Bldg 28A-B


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Figure 3: Seismic Intensity Map for the Northridge Earthquake, January 1994 [Ref. 12]

Mt. SAC Technology Center Bldg 28B


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ASCE 31 Tier 1 Evaluation Results:

Based solely on the checklists presented in Appendix B as excerpted from Reference 2, we find that there are significant deficiencies within the Building 28A-B complex that could lead to serious structural damage during a strong regional earthquake with the Code-expected ground shaking in the Walnut area. The following is a brief summary by building of the Tier 1 evaluation results:

Classroom Building

• The “Shear Stress Check” is marked as non-compliant in the Basic Structural Checklist as the Tier 1 Evaluation (“Quick Check”) of the stresses in the concrete and brick masonry shear walls were found to be significantly higher than the allowable stresses. A deficiency-only Tier 2 analysis was performed to address these non-compliances, which then showed that the concrete shear walls are marginally acceptable, but the brick masonry shear walls are still found to be non-compliant. As such, the building does not qualify for the minimum life safety performance category.

• The “Deflection Compatibility Check” of the supplemental checklist is marked as non-compliant because the interior building columns do not contain any ductile reinforcing details, i.e. the column ties are widely spaced at 14” to 16”, and the ties are closed with 90 degree hooks. This lack of ductile detailing can lead to loss of core integrity and collapse under heavy secondary shear and flexural loading.

Shops Building

• The “Adjacent Buildings Check” is marked non-compliant because the desired building-to-building spacing of 4% of the lowest building height is not met. The actual building separation is 2” and the 4% value is 13”.

• The “Wall Anchorage Check” is marked non-compliant because the perimeter of the poured gypsum roof is connected to the heavy concrete all panels with only a small angle and unspecified connections to the roof.

• The “Girder/Column Check” is marked non-compliant because the connection only consists of two large diameter bolts with a 6” edge distance to the face of pilaster.

• The “Girders Check” of the supplemental checklist is marked non-compliant as noted for the same reasons as the aforementioned Girder/Column check.

Lecture Hall & Administration

• The “Adjacent Buildings Check” is marked as non-compliant because the required separation of 4% of the lower building height is about 6”, and the actual separation is 1-1/2”.


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• The “Girder/Column Check” is marked as non-compliant because the girders rest on pilasters with only two anchor bolts without special straps or ties to prevent anchor bolt breakout.

Test Cells

The Test Cells structure is very stiff and rugged and has not been found to be susceptible to structural damage beyond the desired Enhanced Life Safety performance level.

Seismic Performance:

The overall seismic evaluation included a site visit, a review of available drawings [Ref. 2], Tier 1 and limited Tier 2 evaluation of potential seismic deficiencies using ASCE 31 “Seismic Evaluation of Existing Buildings” [Ref. 1] (see above paragraph), a preliminary assessment of projected seismic performance in a major earthquake based on published data [Refs. 3-15], judgment and experience in investigation of past earthquake performance and research for similar buildings. Detailed assessment of nonstructural components is beyond the scope of this project.

The performance level used in this evaluation was “Enhanced Life Safety” in order to meet DSA’s expectations for somewhat better performance than that provided by minimal life safety provisions. As defined by ASCE 31, the minimum “Life Safety” level is a level of performance “that includes damage to both structural and nonstructural components during a design earthquake, such that (a) partial or total structural collapse does not occur, and (b) damage to nonstructural components is non-life-threatening.” The enhanced life safety performance level allows for some minor but significant damage to the structure, with the intent that occupants of the building will be able to exit the facility safely following a major seismic event.

A brief overview of the anticipated seismic performance for each building within the Technology Center Building A-B complex is given below. Note that all structures within the building complex were approved for construction in 1968, and as-built drawings used in part to perform this evaluation were dated April 23, 1971. This date is noteworthy as it means that construction was completed or largely completed prior to the San Fernando earthquake of February 9, 1971. In this earthquake, many buildings similar to those of the Technology Center Building A-B complex were heavily damaged. As a result of this damage, there were significant design practice and building code changes directly applicable to much of the design and detailing shown on the record drawings for these buildings.

Classroom Building – 28B

As indicated above, the building was designed and constructed in the circa mid-1960s to 1971 timeframe. At this time in the evolution of building codes and structural design practice in earthquake areas, particularly in Southern California, research into design of concrete structures to be ductile (i.e. resistant to sudden failure following initial seismic induced damage such as cracking and spalling) was in its infancy, and code requirements were not in place. This all changed as a result of the severe damage to and collapse of concrete buildings and bridges in the 1971 San Fernando (“Sylmar”) earthquake. Following the San Fernando quake, much research took place and the building codes (e.g. UBC) and materials design publications (e.g. ACI 318 for concrete) were


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updated to include provisions for making concrete structures ductile – i.e. resistant to failure or collapse after the onset of damage due to strong shaking. Though the Technology Center Building 28B was not designed in accordance with the ductility provisions of later codes, it is of such solid, monolithic construction with continuous seismic load paths that it is judged unlikely to experience widespread failure of key structural elements, which could lead to partial or total collapse. However, buildings of this vintage tend to be vulnerable to significant structural damage because they were designed for far less seismic loading than modern codes prescribe, and the detailing of load transfer points and connections in these older buildings does not reflect the lessons learned from the 1971 San Fernando and later earthquakes, and the ensuing research and code changes. In light of these conditions, and the results of the Tier 1 and 2 analyses described above, we find that the Technology Center Building 28B has two significant deficiencies that we recommend for further analysis and possible strengthening:

1. Shear Wall Damage: The building is subject to significant cracking and spalling in both the reinforced concrete and masonry shear walls, but the damage to the masonry shear walls could be serious enough to cause concern for occupant safety and extended building closure for damage repairs (assuming the repairs are feasible and cost-effective, which may not be the case). This level of damage has been observed in numerous past earthquakes, and is typically expressed as large, “X” shaped cracks that are very visible and often extend the full length and through the thickness of the walls. Reinforced concrete walls with two curtains of steel are highly resistant to serious damage beyond the appearance of X-cracking; however, brick masonry shear walls with only a single layer of reinforcing are weaker and more brittle (i.e. less ductile), and much more vulnerable to serious damage (e.g. spalling of large sections of structural wall materials) following the onset of this initial cracking. This level of performance is well outside the acceptable range in terms of the “enhanced” Life Safety performance level required by DSA.

2. Interior Column Damage: The typical interior building columns (see Figures 4 and 5 below) do not contain the ductile reinforcing details required in the new code, largely as a result of column damage in the 1971 San Fernando quake. Instead, these columns contain ties that have 90 degree bends (instead of the currently required 135 degree bends, and the ties are spaced at 16” on center over most of the height, instead of the 4” to 6” required by current codes. As a result, the columns can experience severe cracking, spalling and crushing of the concrete core due to secondary building floor sway loading, as well as possible vertical shocks due to ground thrusts (which occurred extensively in the 1994 Northridge earthquake).


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Figure 4 – Typical Interior Column Cross Section for Classroom Building 28B

Note 90 degree bend to typical horizontal ties


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Figure 5 – Typical Interior Column Elevation for Classroom Building 28B

Note column ties spaced at 16”


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Shops Building – 28A The Shops Building has a flexible horizontal rod X-braced roof diaphragm with a 2-1/2” thick poured gypsum topping for insulation (though gypsum roof decks have some significant in-plane strength and capacity, and are often reinforced with wire mesh, they are not considered a structural diaphragm when used in conjunction with an extensive, large diameter rod bracing system). This flexible diaphragm supports a very heavy and rigid shearwall system composed of both precast and cast-in-place concrete walls. This type of structure is very similar structurally and dynamically to typical industrial concrete tilt-up buildings with wood roof systems, i.e. flexible roof diaphragms and a stiff, heavy shearwall system. The problem with this type of structure is that it tends to exhibit separation between the flexible roof system and the heavy wall system if the roof-to-wall connections are not designed for both ductility and very high force levels. Additionally, the flexible roof system itself has been very vulnerable to in-plane damage such as tearing and buckling of roof elements and separation from walls at corner conditions. This type of vulnerable behavior was exhibited in the 1971 San Fernando quake, the 1987 Whittier quake, the 1989 Loma Prieta quake, and even the 1994 Northridge earthquake. Following each quake beginning in 1971, the building code, i.e. UBC, was updated to counter the observed damage effects, but it appears that the code changes after the 1994 quake finally have accounted for the exhibited behaviors and damage to this type of building, and future designs should do very well in major earthquakes. In light of the above, it is judged that the Shops Building contains a number of deficiencies as identified above during the ASCE 31 Tier 1 checklist process that can lead to the seismic performance predictions discussed below:

1. Pounding with Adjacent Buildings: The Shops Building borders on both the Classroom Building 28B and the Lecture Hall & Administration Building. The separation at the former interface is 2”, and 1-1/2” at the latter. While the Classroom Building is very stiff, the Shops Building is not, and it is conceivable that the two buildings will pound in a large earthquake. It is unlikely that the large Classroom Building will experience significant damage due to this pounding, the roof system of the Shops Building cannot resist such impacts without being damaged. Where the Shops Building and Lecture Hall & Administration Building come together, the minimal 1-1/2” separation leaves little room for relative movements of the two buildings. Though both roof systems are light, they are also flexible and some impacts could occur. These impacts would likely be damaging to both buildings.

2. Out-Of-Plane Wall Anchorage: This term is widely used to describe the most critical connections in this type of structure – the connection between the flexible roof diaphragm and the heavy, rigid precast or cast-in-place wall systems. For the Shops Building, the connection along the perimeter of the building between the gypsum roof and the walls is an angle or channel bolted to the walls that supports the poured gypsum panels. This is a very weak connection that was not designed to resist significant out of plane loading. The significant connections are the TG supports where they rest upon the wall pilasters (see Figure 6 below), and the purlin-to-wall connections at the east and west ends. The latter connections can resist substantial out of plane loads, but the former condition is subject to significant damage because the load levels are very high and concentrated at a single point. This occurs because the precast concrete panels must span horizontally to the pilasters (they cannot span vertically at all because of the weakness of the roof to wall connection at the


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poured gypsum panel supports described above. Since the cyclic (tension-compression) load gathers at the top of the pilasters, there is a great tendency to pull the roof away from the pilaster, and only the two embedded bolts at the top of the pilaster resist this loading. Past earthquake damage experience tells us that serious damage and possible failure of the TG support leading to roof collapse can occur at these locations.

Figure 6 – Shops Building 28A TSG to Pilaster Connection

Two anchor bolts with only 6” edge distance is not adequate to prevent bolt breakout and failure of the support.


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Lecture Hall & Administration Building: This building is composed of a light weight metal deck roof system supported by 9” brick masonry walls. The issues for this building are essentially the same for concrete tilt-ups in general, and the Shops Building above – light roof and heavy walls. The key difference for this building is that it is small in plan and the diaphragm spans are small; thus, it is anticipated that there will be little tendency for the roof diaphragm to be energized by earthquake shaking to the extent that significant diaphragm sway occurs. As a result, the concern of failure of roof-to-wall anchors and in-plane diaphragm damage is small. Nonetheless, there are two areas of concern that result from the ASCE 31 analysis that warrant discussion of potential related earthquake damage:

1. Pounding: There is only 1-1/2” of separation between the Lecture Hall & Administration Building and the adjacent Shops Building. This is not adequate to prevent pounding because both roof systems are relatively flexible. The damage due to pounding is expected to entail local crushing of roofing materials, metal deck and steel beams for the Lecture Hall & Administration Building. For the Shops Building, the damage would likely be less significant, probably in the form of scarring and spalling of the concrete tilt-up panels.

2. Beam to Wall Connections: Where the girders over the Lecture Hall are supported by the brick masonry wall pilasters, the connection is essentially the same as shown in Figure 6 above for the Shops Building, except on a somewhat smaller scale. As such, it is anticipated that some significant damage could occur at this location where the roof may have a tendency to separate from the walls.

Test Cells: As indicated above, this building has no ASCE 31 checklist deficiencies, nor does this type of building have a history of significant damage in past major earthquakes. Because of its small size relative to its strength, it is anticipated that very little deformations will occur within this structure during strong ground shaking. We therefore anticipate that very little damage would occur, possibly some minor wall cracking in the worst case. Planned Architectural Renovations: Planned renovations to the facility have been reviewed in the form of preliminary architectural sketches depicting new room layouts and functions. The purpose of this review was to make a preliminary assessment of the feasibility of the planned work in light of the seismic risk to the facilities and the proposed retrofit measures. In this regard, we find that the planned architectural renovations appear feasible; however, the addition of new openings in the exterior walls of the Classroom Building 28B could trigger the need for extensive new shotcrete applied to the exterior walls. Depending on the extent of desired wall openings, such additional shotcrete work could add several hundred thousand dollars in cost.

VI. SITE OBSERVATIONS:

IDS visited the site on April 28, 2008 and performed a visual observation of the readily accessible areas of the building. The site investigation included a visual tour of the exterior of the building, the


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building roof, mechanical rooms, and a visual survey at the interior of the building. No testing or destructive investigation was conducted during this visit.

It appears that the building was generally constructed in conformance with the available drawings. It also appeared to be in good condition. Photos #1-12 on the following pages depict typical observations made during the site visit.


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Site Observation Photos

Photo #1: South Side, Looking N from Parking Area

Photo #2: East Side Looking NW

Photo #3: East Side, Looking West at Adjacent Test Cells Building

Photo #4: West Side, Looking NE from Adjacent Test Cells and Shops Building


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Site Observation Photos (continued)

Photo #5: Interior of Shops Building, Structurally Independent of Bldg. 28B

Photo #6: Roof of Shops Building from Bldg 28B, Looking NE

Photo #7: High Bay Amphitheater Style in Lecture Hall Building

Photo #8: Building Entrance. Very Few Exterior Openings


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Site Observation Photos (continued)

Photo #9: Interior Corridor. Interior Walls are Non-Structural

Photo #10: End Stairwell with Structural Shear Walls on Each Side

Photo #11: Rooftop View/Tower and Ancillary Building Equipment on 28B

Photo #12: Rooftop Equipment on 28B


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VII. FINDINGS AND RECOMMENDATIONS

Possible Retrofit Concepts:

The key to bringing the various structures within the Technology Center Building 28A-B complex into compliance with DSA’s Enhanced Life Safety performance category is to address the key areas of concern described above. Briefly, corrective retrofit measures for each of the above areas of concern for seismic performance are described below: Classroom Building - 28B

1. Strengthen Brick Masonry Shear Walls: The most common and economical means for achieving a significant increase in strength and damage resistance to shearwalls is to apply a 6” (+/-) thick coating of reinforced shotcrete. Shotcrete is essentially a concrete mix that is sprayed under high pressure onto the wall; separate hoses for the water and cement/aggregate components come together at the nozzle and are mixed together as the blast of ingredients is expelled and impacts the wall. The shotcrete can be applied to the interior of the walls, which becomes feasible if the building interior is demolished to make way for future construction and therefore uninhibited access is available to the perimeter walls for shotcreting. Figure A-1 of Appendix A shows a cross section of an exterior brick masonry shear wall that is strengthened with shotcrete from the basement wall to the third floor slab level.

2. Strengthen Selected Interior Columns: As indicated above, the interior columns lack ductile detailing in the form of closed hoops and close spacing for the column ties. The hoops have 90 degree hooks and the spacing is 14” to 16”. The most common and economical solution to this deficiency is to apply multiple wraps of the columns with a fiber reinforced polymer fabric (carbon or glass fiber are most common). See Figure A-2

Shops Building - 28A

1. Mitigate or Minimize Pounding Damage: This problem can be easy and cost effective to deal with in some locations, and very difficult and costly in other locations. Where the Shops Building mezzanine is next to the exterior wall of the Classroom Building, the wood floor system can be cut back and reconstructed. Where the concrete panels of the Shops Building are next to the concrete columns on the exterior walls of the Classroom Building, it is not a simple matter to “cut away” portions of either structure to create an impact-free zone. Much more thought, analysis and design work is necessary in order to develop a cost-effective solution which balances the risk of damage with the cost of retrofit. For the purposes of this report, an allowance will be made to accommodate the potential cost of this item.

2. Strengthen Girder Supports at Pilasters: The purpose of the proposed retrofit approach shown in Figure A-3 below is to prevent the tapered steel girders from pulling away from their support positions on the precast panel pilasters. This connection retrofit entails bolting or welding steel “shoes” to either side of the girders, and bolting the shoes through the walls


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to backing plates on the exterior. This connection is very strong and ductile and will assure that the girder does not become unseated during strong ground shaking.

Lecture Hall & Administration:

This building may require seismic retrofit measures to mitigate or minimize the pounding effects with the Shops Building, and to prevent the steel roof girders from dislodging from their pilaster supports due to roof-to-wall separation forces discussed above. The solutions are similar to those discussed above for the Shops Building and appropriate cost allowances can be made using the cost data for the Shops Building.

Test Cells:

As indicated, the Test Cells Building requires no retrofit in order to reasonably assure seismic performance consistent with that required of the “Enhanced Life Safety” protection category.

Opinion of Probable Cost:

Our opinion of the probable cost to implement the recommendations indicated in this report is $1,200,000. Refer to the table below which briefly summarizes the key elements of this value. Our opinion of probable cost at this time is based merely on experience and judgment, and should be more defined as more information is obtained in future studies. The opinion of probable cost covers structural upgrade only, with the assumption that the building will be closed during construction, thus allowing for uninhibited access to perform the structural work. Additional costs for related architectural modifications, ADA compliance, fire and life safety improvements and access modifications are not included in this opinion of probable cost, though a cost allowance for equipment anchorage and bracing has been added.


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Table of Probable Cost Values

Component Cost

Classroom Building – 28B

1. Apply 6” of reinforced shotcrete to first and second stories on north and south side brick masonry walls (approximately 7,600 square feet) $380,000

2. Apply a reinforced polymer fiber wrap to the interior columns from the basement to the roof level $300,000

Shops Building – 28A

3. Allowance for mitigation of pounding effects with Classroom Building $ 50,000

4. Retrofit TS girder support locations with out-of-plane wall anchors $ 30,000

Lecture Hall & Administration Building

5. Allowance for mitigation of pounding effects with Shops Building $ 25,000

6 Retrofit roof beams at pilaster support locations with out-of-plane anchors $ 15,000

7. Allowance for seismic anchorage of key equipment and systems $ 75,000

Subtotal $875,000

General & special conditions plus Contractor OH & profit @ 25% $219,000

Engineering contingency @ 5% $ 55,000

Grand total $1,149,000

Use $1,200,000


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Recommended Next Steps:

In order to confirm the areas judged at this time to require strengthening, and to determine the cost and construction feasibility of the potential retrofit schemes described above, it is recommended that the next steps consist of the following:

1. Conduct limited testing of existing primary structural systems, including shear walls, slabs, columns, beams and foundations, in order to confirm that the actual strength is consistent with or exceeds the strengths specified on the drawings. This would entail extracting rebar and concrete core samples for laboratory strength testing, and chemical analysis for the reinforcing steel.

2. Conduct a detailed structural analysis of the entire building in conformance with ASCE 31

Tier 2 or Tier 3 requirements.

3. Identify those structural elements that do not meet current acceptance criteria for stress, deflection and detailing.

4. Develop schematic seismic retrofit designs that are substantiated by calculations just to the

level necessary to have confidence in their adequacy and feasibility.

5. Develop an opinion of probable cost for the proposed upgrade in order to facilitate decision-making and budgeting as appropriate.

6. Prepare a final report of all project work including proposed upgrade sketches and cost

projections, and present project results outlining major findings of the project.


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Appendix A – Conceptual Seismic Retrofit Sketch

The following sketches are preliminary and not for construction. This sketch was prepared for the sole purpose of communicating the general type of work described in the report, and to assist in preparing an opinion of probable cost for seismic retrofit.

Figure A-1: New Shotcrete Wall on the North and South Sides of the Building

6” Shotcrete

#5 reinforcing at 12” each way centered

#3 hooked epoxy dowels at 24” each way

Epoxy dowels at the first, second and third floor levels


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Figure A-2: Fiber Reinforced Polymer Wrap for Interior Columns

Up to three layers of carbon or glass fiber reinforced polymer

Grind corners of concrete column to achieve smooth radius


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Figure A-4: Out of Plane Anchorage for Girder Support at Pilaster

Bolted or welded steel “shoe” on each side of tapered steel girder

1” diameter through-bolts on each side with ½” backing plates


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Appendix B – ASCE 31 Tier 1 Checklists

The following checklists were prepared in order to obtain a general understanding as to the types of deficiencies that may be observed from drawing reviews and site observations for the category of structure that best describes each building in the Mt. SAC Technology Center Building 28A-B complex.

Each of the evaluation statements on the following checklists shall be marked compliant (C), non-compliant (NC), or not applicable (N/A) for a Tier 1 Evaluation. Compliant statements identify issues that are acceptable according to the criteria of this standard, while non-compliant statements identify issues that require further investigation. Certain statements may not apply to the buildings being evaluated. For non-compliant evaluation statements, the design professional may choose to conduct further investigation using the corresponding Tier 2 evaluation procedure; corresponding section numbers are in parentheses following each evaluation statement.

CLASSROOM BUILDING – 29B

ASCE 31 Basic Structural Checklist for Building Type C2 Concrete Shear Walls with Stiff Diaphragms

C NC N/A COMMENT

BUILDING SYSTEM

LOAD PATH: The structure shall contain a minimum of one complete load path for Life Safety and Immediate Occupancy for seismic force effects from any horizontal direction that serves to transfer the inertial forces from the mass to the foundation. (Tier 2: Sec. 4.3.1.1)

Primary lateral load path is rigid concrete floor and roof diaphragms spanning to concrete joists and shear walls.

MEZZANINES: Interior mezzanine levels shall be braced independently from the main structure, or shall be anchored to the lateral-force-resisting elements of the main structure. (Tier 2: Sec. 4.3.1.3)

No mezzanines.

WEAK STORY: The strength of the lateral-force-resisting system in any story shall not be less than 80% of the

No weak stories.

C3.7.9 Basic Structural Checklist for Building Type C2

These buildings have floor and roof framing that consists of cast-in-place concrete slabs, concrete beams, one-way joists, two-way waffle joists, or flat slabs. Floors are supported on concrete columns or bearing walls. Lateral forces are resisted by cast-in-place concrete shear walls. In older construction, shear walls are lightly reinforced, but often extend throughout the building. In more recent construction, shear walls occur in isolated locations and are more heavily reinforced with boundary elements and closely spaced ties to provide ductile performance. The diaphragms consist of concrete slabs and are stiff relative to the walls. Foundations consist of concrete spread footings or deep pile foundations, or deep foundations.


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C NC N/A COMMENT

strength in an adjacent story, above or below, for Life-Safety and Immediate Occupancy. (Tier 2: Sec. 4.3.2.1)

SOFT STORY: The stiffness of the lateral-force-resisting system in any story shall not be less than 70% of the lateral-force-resisting system stiffness in an adjacent story above or below, or less than 80% of the average lateral-force-resisting system stiffness off the three stories above or below for Life Safety and Immediate Occupancy. (Tier 2: Sec. 4.3.2.2)

No soft stories.

GEOMETRY: There shall be no changes in horizontal dimension of the lateral-force-resisting system of more than 30% in a story relative to adjacent stories for Life Safety and Immediate Occupancy, excluding one-story penthouses and mezzanines. (Tier 2: Sec. 4.3.2.3)

Uniform geometry.

VERTICAL DISCONTINUITIES: All vertical elements in the lateral-force-resisting system shall be continuous to the foundation. (Tier 2: Sec. 4.3.2.4)

No vertical discontinuities.

MASS: There shall be no change in effective mass more than 50% from one story to the next for Life Safety and Immediate Occupancy. Light roofs, penthouses and mezzanines need not be considered. (Tier 2: Sec. 4.3.2.5)

No significant change in effective mass from one story to the next.

TORSION: The estimated distance between the story center of mass and the story center of rigidity shall be less than 20% of the building width in either plan dimension for Life Safety and Immediate Occupancy. (Tier 2: Sec. 4.3.2.6)

Torsion is minimal.

DETERIORATION OF CONCRETE: There shall be no visible deterioration of concrete or reinforcing steel in any of the vertical- or lateral-force-resisting elements. (Tier 2: Sec. 4.3.3.4)

Building in good shape based on visual examination in readily accessible areas.

POST-TENSIONING ANCHORS: There shall be no evidence of corrosion or spalling in the vicinity of post-tensioning or end fittings. Coil anchors shall not have been used. (Tier 2: Sec. 4.3.3.5)

No post-tensioning.

CONCRETE WALL CRACKS: All existing diagonal cracks in wall elements shall be less than 1/8" for Life Safety and 1/16" for Immediate Occupancy, shall not be concentrated in one location, and shall not form an X pattern. (Tier 2: Sec. 4.3.3.9)

No visibly significant cracking in any walls where structure is visible.

LATERAL FORCE RESISTING SYSTEM

COMPLETE FRAMES: Steel or concrete frames classified as secondary components shall form a complete vertical load carrying system. (Tier 2: Sec. 4.4.1.6.1)

No frames.

REDUNDANCY: The number of lines of shear walls in No less than two lines in each


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C NC N/A COMMENT

each principal direction shall be greater than or equal to 2 for Life Safety and Immediate Occupancy. (Tier 2: Sec. 4.4.2.1.1)

direction.

SHEAR STRESS CHECK: The shear stress in the concrete shear walls, calculated using the Quick Check procedure of Section 3.5.3.3, shall be less than the greater of 100 psi or

cf'2 for Life Safety and Immediate Occupancy. (Tier 2: Sec. 4.4.2.2.1)

Quick Check procedure yielded concrete stresses in excess of

cf'2 , but acceptance criteria met for deficiency-only Tier 2 analysis.

REINFORCING STEEL: The ratio of reinforcing steel area to gross concrete area shall be not less than 0.0015 in the vertical direction and 0.0025 in the horizontal direction for Life Safety and Immediate Occupancy. The spacing of reinforcing steel shall be equal to or less than 18” for Life Safety and Immediate Occupancy. (Tier 2: Sec. 4.4.2.2.2)

(2)-#4V @ 18” o.c. (1 each face) and (2)-#4H @ 16” o.c. (1 each face) typical wall reinforcing amounts to a ratio of 0.0022 in the vertical direction and 0.0025 in the horizontal direction.

CONNECTIONS

TRANSFER TO SHEAR WALLS: Diaphragms shall be connected for transfer of loads to the shear walls for Life Safety and the connections shall be able to develop the lesser of the shear strength of the walls or diaphragms for Immediate Occupancy. (Tier 2: Sec. 4.6.2.1)

Diaphragms are anchored to shear walls.

FOUNDATION DOWELS: Wall reinforcement shall be doweled into the foundation for Life Safety and the dowels shall be able to develop the lesser of the strength of the walls or the uplift capacity of the foundation for Immediate Occupancy. (Tier 2: Sec. 4.6.3.5)

Grade beams are integral with shear walls and slab at basement level, but are not doweled into the pile caps.

ASCE 31 Supplemental Structural Checklist for Building Type C2 Concrete Shear Walls with Stiff Diaphragms

C NC N/A COMMENT


DEFLECTION COMPATIBILITY: Secondary components shall have the shear capacity to develop the flexural strength of the components for Life Safety and shall meet the requirements of 4.4.1.4.9, 4.4.1.4.10, 4.4.1.4.11, 4.4.1.4.12, and 4.4.1.4.15 for Immediate Occupancy. (Tier 2: Sec. 4.4.1.6.2)

Building columns do not exhibit ductile detailing; the column ties are spaced at 14” to 16” and have 90 degree hooks.

FLAT SLABS: Flat slabs/plates not part of lateral-force-resisting system shall have continuous bottom steel through the column joints for Life Safety and Immediate

All floor and roof slabs are part of the lateral load carrying system.


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C NC N/A COMMENT

Occupancy. (Tier 2: Sec. 4.4.1.6.3)

COUPLING BEAMS: The stirrups in coupling beams over means of egress shall be spaced at or less than d/2 and shall be anchored into the confined core of the beam with hooks of 135º or more for Life Safety. All coupling beams shall comply with the requirements above and shall have the capacity in shear to develop the uplift capacity of the adjacent wall for Immediate Occupancy. (Tier 2: Sec. 4.4.2.2.3)

Beams do not function as coupling beams.

OVERTURNING: All shear walls shall have aspect ratios less than 4 to 1. Wall piers need not be considered. This statement shall apply to the Immediate Occupancy Performance Level only. (Tier 2: Sec. 4.4.2.2.4)

Immediate Occupancy is not required.

CONFINEMENT REINFORCING: For shear walls with aspect ratios greater than 2 to 1, the boundary elements shall be confined with spirals or ties with spacing less than 8db. This statement shall apply to the Immediate Occupancy Performance Level only. (Tier 2: Sec. 4.4.2.2.5)

Though the boundary elements do not comply with this requirement and the shear wall aspect ratios are less than 1:1, Immediate Occupancy does not apply to this building.

REINFORCING AT OPENINGS: There shall be added trim reinforcement around all wall openings with a dimension greater than three times the thickness of the wall. This statement shall apply to the Immediate Occupancy Performance Level only. (Tier 2: Sec. 4.4.2.2.6)

Trim reinforcing is provided, even though Immediate Occupancy level does not apply.

WALL THICKNESS: Thickness of bearing walls shall not be less than 1/25 the unsupported height or length, whichever is shorter, nor less than 4”. This statement shall apply to the Immediate Occupancy Performance Level only. (Tier 2: Sec. 4.4.2.2.7)

Walls meet these criteria though the Immediate Occupancy level does not apply.

DIAPHRAGMS

DIAPHRAGM CONTINUITY: The diaphragm shall not be composed of split-level floors and shall not have expansion joints. (Tier 2: Sec. 4.5.1.1)

Floor and roof diaphragms are continuous.

OPENINGS AT SHEAR WALLS: Diaphragm openings immediately adjacent to the shear walls shall be less than 25% of the wall length for Life Safety and 15% of the wall length for Immediate Occupancy. (Tier 2: Sec. 4.5.1.4)

There are no diaphragm openings immediately adjacent to shear walls.

PLAN IRREGULARITIES: There shall be tensile capacity to develop the strength of the diaphragm at re-entrant corners or other locations of plan irregularities. This statement shall apply to the Immediate Occupancy Performance Level only. (Tier 2: Sec. 4.5.1.7)

The building is very regular in plan.

DIAPHRAGM REINFORCEMENT AT OPENINGS: There shall be reinforcing around all diaphragm openings larger than 50% of the building width in either major plan

There are no openings this large, and the Immediate Occupancy


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C NC N/A COMMENT

dimension. This statement shall apply to the Immediate Occupancy Performance Level only. (Tier 2: Sec. 4.5.1.8)

level does not apply.

CONNECTIONS

UPLIFT AT PILE CAPS: Pile caps shall have top reinforcement and piles shall be anchored to the pile caps for Life Safety, and the pile cap reinforcement and pile anchorage shall be able to develop the tensile capacity of the piles for Immediate Occupancy. (Tier 2: Sec. 4.6.3.10)

The pile caps do not have top reinforcing, but there should be no net uplift on the pile caps because shear walls are long and heavy. Piles are anchored to the pile caps.

ASCE 31 Basic Structural Checklist for Building Type RM2 Reinforced Masonry Bearing Wall Buildings with Rigid or Stiff Diaphragms

C NC N/A COMMENT

BUILDING SYSTEM


Primary lateral load path is rigid concrete floor and roof diaphragms spanning to concrete joists and shear walls.


No mezzanines.

WEAK STORY: The strength of the lateral-force-resisting system in any story shall not be less than 80% of the strength in an adjacent story, above or below, for Life-Safety and Immediate Occupancy. (Tier 2: Sec. 4.3.2.1)

No weak stories.

SOFT STORY: The stiffness of the lateral-force-resisting system in any story shall not be less than 70% of the lateral-force-resisting system stiffness in an adjacent story above or below, or less than 80% of the average lateral-force-resisting system stiffness off the three stories above or below for Life Safety and Immediate Occupancy. (Tier 2:

No soft stories.

C3.7.14 Basic Structural Checklist For Building Type RM2

These buildings have bearing walls that consist of reinforced brick or concrete block masonry. Diaphragms consist of metal deck with concrete fill, precast concrete planks, tees, or double-tees, with or without a cast-in-place concrete topping slab, and are stiff relative to the walls. The floor and roof framing is supported on interior steel or concrete frames or interior reinforced masonry walls.


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Sec. 4.3.2.2)


Uniform geometry.




No significant change in effective mass from one story to the next.


Torsion is minimal.



MASONRY UNITS: There shall be no visible deterioration of masonry units. (Tier 2: Sec. 4.3.3.7)


MASONRY JOINTS: The mortar shall not be easily scraped away from the joints by hand with a metal tool, and there shall be no areas of eroded mortar. (Tier 2: Sec. 4.3.3.8)

REINFORCED MASONRY WALL CRACKS: All existing diagonal cracks in wall elements shall be less than 1/8" for Life Safety and 1/16" for Immediate Occupancy, shall not be concentrated in one location, and shall not form an X pattern. (Tier 2: Sec. 4.3.3.10)


REDUNDANCY: The number of lines of shear walls in each principal direction shall be greater than or equal to 2 for Life Safety and Immediate Occupancy. (Tier 2: Sec. 4.4.2.1.1)

There are two shear wall lines in each direction at each level.

SHEAR STRESS CHECK: The shear stress in the reinforced masonry shear walls, calculated using the Quick Check procedure of Section 3.5.3.3, shall be less than 70 psi for Life Safety and Immediate Occupancy. (Tier 2: Sec. 4.4.2.4.1)

Quick Check procedure yielded masonry stresses in excess of 70 psi, but acceptance criteria met for deficiency-only Tier 2 analysis for shear walls at two


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uppermost levels. Acceptance criteria also met for deficiency-only Tier 2 analysis for lower level shear walls with shotcrete retrofit.

REINFORCING STEEL: The total vertical and horizontal reinforcing steel ratio in reinforced masonry walls shall be greater than 0.002 for Life Safety and Immediate Occupancy of the wall with the minimum of 0.0007 for Life Safety and Immediate Occupancy in either of the two directions; the spacing of reinforcing steel shall be less than 48” for Life Safety and Immediate Occupancy; and all vertical bars shall extend to the top of the walls. (Tier 2: Sec. 4.4.2.4.2)

Typical wall reinforcing is #5 @ 24” o.c. each way, which amounts to a total ratio of 0.005 and a ratio of 0.0028 in the horizontal or vertical directions.

DIAPHRAGMS

TOPPING SLAB: Precast concrete diaphragm elements shall be interconnected by a continuous reinforced concrete topping slab. (Tier 2: Sec. 4.5.5.1)

No precast concrete diaphragm elements.

CONNECTIONS

WALL ANCHORAGE: Exterior concrete or masonry walls, that are dependent on the diaphragm for lateral support, shall be anchored for out-of-plane forces at each diaphragm level with steel anchors, reinforcing dowels, or straps that are developed into the diaphragm. Connections shall have adequate strength to resist the connection force calculated in the Quick Check Procedure of Section 3.5.3.7. (Tier 2: Sec. 4.6.1.1)

Spandrel beams dowel into exterior masonry shear walls.

TRANSFER TO SHEAR WALLS: Diaphragms shall be connected for transfer of loads to the shear walls for Life Safety and the connections shall be able to develop the lesser of the shear strength of the walls for Immediate Occupancy. (Tier 2: Sec. 4.6.2.1)

Diaphragms are connected to shear walls and transfer loads through the spandrel beams.

TOPPING SLAB TO WALLS OR FRAMES: Reinforced concrete topping slabs that interconnect the precast concrete diaphragm elements shall be doweled for transfer of forces into the shear wall or frame elements for Life Safety and the dowels shall be able to develop the lesser of the shear strength of the walls, frames, or slabs for Immediate Occupancy. (Tier 2: Sec. 4.6.2.3)

No precast concrete diaphragm elements.


Exterior masonry shear walls dowel into basement level concrete shear walls, and grade beams are built integrally with concrete shear walls and slab, but concrete shear walls are not doweled into the pile caps.


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GIRDER/COLUMN CONNECTION: There shall be a positive connection utilizing plates, connection hardware, or straps between the girder and the column support. (Tier 2: Sec. 4.6.4.1)

Concrete girder reinforcing runs through concrete column reinforcing.

ASCE 31 Supplemental Structural Checklist for Building Type RM2

Reinforced Masonry Bearing Wall Buildings with Rigid or Stiff Diaphragms

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Trim reinforcing is provided, even though Immediate Occupancy level does not apply.

PROPORTIONS: The height-to-thickness ratio of the shear walls at each story shall be less than 30. This statement shall apply to the Immediate Occupancy Performance Level only. (Tier 2: Sec. 4.4.2.4.4)

Height to thickness ratio of the shear walls at each story is less than 30, plus Immediate Occupancy level does not apply.

DIAPHRAGMS



OPENINGS AT EXTERIOR MASONRY SHEAR WALLS: Diaphragm openings immediately adjacent to exterior masonry shear walls shall not be greater than 8 ft. long for Life Safety and 4 ft. long for Immediate Occupancy. (Tier 2: Sec. 4.5.1.6)



There are no re-entrant corners.

DIAPHRAGM REINFORCEMENT AT OPENINGS: There shall be reinforcing around all diaphragm openings larger than 50% of the building width in either major plan dimension. This statement shall apply to the Immediate Occupancy Performance Level only. (Tier 2: Sec. 4.5.1.8)

There are no openings this large, and the Immediate Occupancy level does not apply.


May 2008


SHOPS BUILDING – 29A

3.7.11 BASIC STRUCTURAL CHECKLIST FOR CUILDING TYPE PC1: PRECAST/TILT-UP CONCRETE SHEAR WALL BUILDINGS WITH FLEXIBLE DIAPHRAGMS

C NC N/A COMMENT

BUILDING SYSTEM


Building has a continuous load path in both directions from roof level to foundation.

ADJACENT BUILDINGS: The clear distance between the building being evaluated and any adjacent building shall be greater than 4% of the height of the shorter building for Life Safety and Immediate Occupancy. (Tier 2: Sec. 4.3.1.2)

4% of the lower building height is 13”, and the actual separation is 2”. Pounding is possible.


The interior mezzanines are connected to the main building shearwalls.


No weak stories.


No soft stories.

C3.7.11 Basic Structural Checklist for Building Type PC1

These buildings have precast concrete perimeter wall panels that are cast on site and tilted into place. Floor and roof framing consists of wood joists, glulam beams, steel beams or open web joists. Framing is supported on interior steel or concrete columns and perimeter concrete bearing walls. The floors and roof consist of wood sheathing or untopped metal deck. Lateral forces are resisted by the precast concrete perimeter wall panels. Wall panels may be solid, or have large window and door openings which cause the panels to behave more as frames than as shear walls. In older construction, wood framing is attached to the walls with wood ledgers. Foundations consist of concrete spread footings or deep pile foundations.


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Only one story; no geometry changes.


Load paths are continuous.


Single story, no mass changes.

DETERIORATION OF WOOD: There shall be no signs of decay, shrinkage, splitting, fire damage, or sagging in any of the wood members and none of the metal connection hardware shall be deteriorated, broken, or loose. (Tier 2: Sec. 4.3.3.1)

No obvious signs of deterioration. Detailed investigation would be required to confirm.

PRECAST CONCRETE WALLS: There shall be no visible deterioration of concrete or reinforcing steel or evidence of distress, especially at the connections. (Tier 2: Sec. 4.3.3.6)

No visible deterioration of precast concrete panels.



Two shear wall lines in each direction.

SHEAR STRESS CHECK: The shear stress in the precast panels, calculated using the Quick Check procedure of Section 3.5.3.3, shall be less than the greater of 100 psi or cf'2 for Life Safety and Immediate Occupancy. (Tier 2: Sec. 4.4.2.3.1)

Light steel frame and gypsum roof does not cause high stress levels in the perimeter shear walls.


Adequate wall reinforcing.

CONNECTIONS

WALL ANCHORAGE: Exterior concrete or masonry walls, that are dependent on the diaphragm for lateral support, shall be anchored for out-of-plane forces at each diaphragm level with steel anchors, reinforcing dowels,

The poured gypsum panels are not adequately anchored to the walls to provide significant out of


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or straps that are developed into the diaphragm. Connections shall have adequate strength to resist the connection force calculated in the Quick Check Procedure of Section 3.5.3.7. (Tier 2: Sec. 4.6.1.1)

plane anchorage. Thus, the wall panels span between pilasters. The pilasters are not sufficiently anchored to the TG roof beams to prevent OOP separation.

WOOD LEDGERS: The connection between the wall panels and the diaphragm shall not induce cross-grain bending or tension in the wood ledgers. (Tier 2: Sec. 4.6.1.2)

The ledgers are steel angles.

TRANSFER TO SHEAR WALLS: Diaphragms shall be connected for transfer of loads to the shear walls for Life Safety and the connections shall be able to develop the lesser of the shear strength of the walls for Immediate Occupancy. (Tier 2: Sec. 4.6.2.1)

Roof tie rod bracing is connected to the walls at the TG roof beam support points on the wall pilasters.

PRECAST WALL PANELS: Precast wall panels shall be connected to the foundation for Life Safety and the connections shall be able to develop the strength of the walls for Immediate Occupancy. (Tier 2: Sec. 4.6.3.7)

The precast panels are continuously tied to the slab on grade for shear transfer. They are not connected to the pile caps.


The TG roof girders have twe 1-1/8” diameter anchors at each pilaster with 6” edge distance. This detail is prone to concrete breakout.


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3.7.11S SUPPLEMENTAL STRUCTURAL CHECKLIST FOR BUILDING TYPE PC1: PRECAST/TILT-UP CONCRETE SHEAR WALL BUILDINGS WITH FLEXIBLE DIAPHRAGMS

This Supplemental Structural Checklist shall be completed when required by Table 3-2. The Basic Structural Checklist shall be completed prior to completing this Supplemental Structural Checklist.

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There are no coupling beams.

WALL OPENINGS: The total width of openings along any perimeter wall line shall constitute less than 75% of the length of any perimeter wall for Life Safety and 50% for Immediate Occupancy with the wall piers having aspect ratios of less than 2 to 1 for Life Safety and Immediate Occupancy. (Tier 2: Sec. 4.4.2.3.3)

Wall openings are not significant.

CORNER OPENINGS: Walls with openings at a building corner larger than the width of a typical panel shall be connected to the remainder of the wall with collector reinforcing. (Tier 2: Sec. 4.4.2.3.4)

Wall openings comply.

PANEL-TO-PANEL CONNECTIONS: Adjacent wall panels shall be interconnected to transfer overturning forces between panels by methods other than welded steel inserts. This statement shall apply to the Immediate Occupancy Performance Level only. (Tier 2: Sec. 4.4.2.3.5)

Enhanced life safety only, Immediate Occupancy not required.


All roof loading is supported by the pilasters. The walls are not bearing walls.

DIAPHRAGMS

CROSS TIES: There shall be continuous cross ties between diaphragm chords. (Tier 2: Sec. 4.5.1.2)

Steel beams running in both directions provide for adequate cross ties.


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The building is very regular.


There are no large roof diaphragm openings.

STRAIGHT SHEATHING: All straight sheathed diaphragms shall have aspect ratios less than 2 to 1 for Life Safety and 1 to 1 for Immediate Occupancy in the direction being considered. (Tier 2: Sec. 4.5.2.1)

Diaphragm is no sheathed.

SPANS: All wood diaphragms with spans greater than 24 ft. for Life Safety and 12 ft. for Immediate Occupancy shall consist of wood structural panels or diagonal sheathing. (Tier 2: Sec. 4.5.2.2)

Diaphragm is not constructed of wood.

UNBLOCKED DIAPHRAGMS: All diagonally sheathed or unblocked wood structural panel diaphragms shall have horizontal spans less than 40 ft. for Life Safety and 30 ft. for Immediate Occupancy and shall have aspect ratios less than or equal to 4 to 1 for Life Safety and 3 to 1 for Immediate Occupancy. (Tier 2: Sec. 4.5.2.3)

Blocking does not apply to a rod braced diaphragm.

OTHER DIAPHRAGMS: The diaphragm shall not consist of a system other than wood, metal deck, concrete or horizontal bracing. (Tier 2: Sec. 4.5.7.1)

Rod braced diaphragm complies.

CONNECTIONS

PRECAST PANEL CONNECTIONS: There shall be at least two anchors from each precast wall panel into the diaphragm elements for Life Safety and the anchors shall be able to develop the strength of the panels for Immediate Occupancy. (Tier 2: Sec. 4.6.1.3)

Each panel is connected to the roof beams at the pilasters.


Though S3 foundation drawing not available, it is likely that the pilasters are anchored to the pile caps, and the piles have rebar into the pile caps. This will need to be confirmed.

GIRDERS: Girders supported by walls or pilasters shall have at least two additional ties securing the anchor bolts for Life Safety and Immediate Occupancy. (Tier 2: Sec. 4.6.4.2)

Girders are not adequately anchored to the tops of the pilasters.


May 2008


LECTURE HALL & ADMINISTRATION

3.7.13 BASIC STRUCTURAL CHECKLIST FOR BUILDING TYPE RM1: REINFORCED MASONRY WALL BUILDINGS WITH FLEXIBLE DIAPHRAGMS

C NC N/A COMMENT

BUILDING SYSTEM


Load paths are continuous from roof the ground level.

ADJACENT BUILDINGS: The clear distance between the building being evaluated and any adjacent building shall be greater than 4% of the height of the shorter building for Life Safety and Immediate Occupancy. (Tier 2: Sec. 4.3.1.2)

4% of 13’ is about 6”, and the actual separation is 1-1/2”. Pounding may occur with the adjacent Shops Building.


No interior mezzanines.


No weak stories.


No soft stories.

GEOMETRY: There shall be no changes in horizontal dimension of the lateral-force-resisting system of more than 30% in a story relative to adjacent stories for Life Safety

One story building; this item does not apply.

C3.7.13 Basic Structural Checklist for Building Type RM1

These buildings have bearing walls that consist of reinforced brick or concrete block masonry. Wood floor and roof framing consist of wood joists, glulam beams and wood posts or small steel columns. Steel floor and roof framing consists of steel beams or open web joists, steel girders and steel columns. Lateral forces are resisted by the reinforced brick or concrete block masonry shear walls. Diaphragms consist of straight or diagonal wood sheathing, plywood or untopped metal deck, and are flexible relative to the walls. Foundations consist of brick or concrete spread footings, or deep foundations.


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and Immediate Occupancy, excluding one-story penthouses and mezzanines. (Tier 2: Sec. 4.3.2.3)




Does not apply to single story building.

DETERIORATION OF WOOD: There shall be no signs of decay, shrinkage, splitting, fire damage, or sagging in any of the wood members and none of the metal connection hardware shall be deteriorated, broken, or loose. (Tier 2: Sec. 4.3.3.1)

No wood construction; does not apply.

MASONRY UNITS: There shall be no visible deterioration of masonry units. (Tier 2: Sec. 4.3.3.7)

Brick masonry walls appeared in good condition.

MASONRY JOINTS: The mortar shall not be easily scraped away from the joints by hand with a metal tool, and there shall be no areas of eroded mortar. (Tier 2: Sec. 4.3.3.8)

Mortar joints appeared to be in good condition.

REINFORCED MASONRY WALL CRACKS: All existing diagonal cracks in wall elements shall be less than 1/8" for Life Safety and 1/16" for Immediate Occupancy, shall not be concentrated in one location, and shall not form an X pattern. (Tier 2: Sec. 4.3.3.10)

No significant wall cracking was observed.



There are at least two lines of shear walls in each direction.

SHEAR STRESS CHECK: The shear stress in the reinforced masonry shear walls, calculated using the Quick Check procedure of Section 3.5.3.3, shall be less than 70 psi for Life Safety and Immediate Occupancy. (Tier 2: Sec. 4.4.2.4.1)

Very light roof deck imposes light seismic shear loads onto the masonry walls.

REINFORCING STEEL: The total vertical and horizontal reinforcing steel ratio in reinforced masonry walls shall be greater than 0.002 for Life Safety and Immediate Occupancy of the wall with the minimum of 0.0007 for Life Safety and Immediate Occupancy in either of the two directions; the spacing of reinforcing steel shall be less than 48” for Life Safety and Immediate Occupancy; and all vertical bars shall extend to the top of the walls. (Tier 2: Sec. 4.4.2.4.2)

Wall reinforcing is adequate.


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CONNECTIONS

WALL ANCHORAGE: Exterior concrete or masonry walls, that are dependent on the diaphragm for lateral support, shall be anchored for out-of-plane forces at each diaphragm level with steel anchors, reinforcing dowels, or straps that are developed into the diaphragm. Connections shall have adequate strength to resist the connection force calculated in the Quick Check Procedure of Section 3.5.3.7. (Tier 2: Sec. 4.6.1.1)

The metal deck diaphragm is continuously welded to the perimeter shear walls via bolted angles or channels. Such connections for small buildings have performed satisfactorily in past major earthquakes.

WOOD LEDGERS: The connection between the wall panels and the diaphragm shall not induce cross-grain bending or tension in the wood ledgers. (Tier 2: Sec. 4.6.1.2)

No wood ledgers.


Metal deck diaphragm is continuously welded to the perimeter shear walls.


Walls, footings and floor slabs are continuously interconnected with reinforcing steel.


The girder-column consists of the typical two-bolt connection that has been known to fail in past major earthquakes.

3.7.13S SUPPLEMENTAL STRUCTURAL CHECKLIST FOR BUILDING TYPE RM1: REINFORCED MASONRY BEARING WALL BUILDINGS WITH FLEXIBLE DIAPHRAGMS

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REINFORCING AT OPENINGS: All wall openings that interrupt rebar shall have trim reinforcing on all sides. This statement shall apply to the Immediate Occupancy Performance Level only. (Tier 2: Sec. 4.4.2.4.3)

This building is not Immediate Occupancy.

PROPORTIONS: The height-to-thickness ratio of the shear walls at each story shall be less than 30. This statement shall apply to the Immediate Occupancy Performance Level only. (Tier 2: Sec. 4.4.2.4.4)

Actual height to thickness ratio is 17, well within the requirements.


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DIAPHRAGMS

CROSS TIES: There shall be continuous cross ties between diaphragm chords. (Tier 2: Sec. 4.5.1.2)

Steel beam and purlin lines in both directions provide for sufficient crossties.


There are no large openings in the diaphragm.

OPENINGS AT EXTERIOR MASONRY SHEAR WALLS: Diaphragm openings immediately adjacent to exterior masonry shear walls shall not be greater than 8 ft. long for Life Safety and 4 ft. long for Immediate Occupancy. (Tier 2: Sec. 4.5.1.6)

There are no large openings in the diaphragm.


This is not an Immediate Occupancy facility.



STRAIGHT SHEATHING: All straight sheathed diaphragms shall have aspect ratios less than 2 to 1 for Life Safety and 1 to 1 for Immediate Occupancy in the direction being considered. (Tier 2: Sec. 4.5.2.1)

Does not apply. This is a metal deck roof.

SPANS: All wood diaphragms with spans greater than 24 ft. for Life Safety and 12 ft. for Immediate Occupancy shall consist of wood structural panels or diagonal sheathing. (Tier 2: Sec. 4.5.2.2)


UNBLOCKED DIAPHRAGMS: All diagonally sheathed or unblocked wood structural panel diaphragms shall have horizontal spans less than 40 ft. for Life Safety and 30 ft. for Immediate Occupancy and shall have aspect ratios less than or equal to 4 to 1 for Life Safety and 3 to 1 for Immediate Occupancy. (Tier 2: Sec. 4.5.2.3)


NON-CONCRETE FILLED DIAPHRAGMS: Untopped metal deck diaphragms or metal deck diaphragms with fill other than concrete shall consist of horizontal spans of less than 40 ft. and shall have span/depth ratios less than 4 to 1. This statement shall apply to the Immediate Occupancy Performance Level only. (Tier 2: Sec. 4.5.3.1)



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OTHER DIAPHRAGMS: The diaphragm shall not consist of a system other than wood, metal deck, concrete or horizontal bracing. (Tier 2: Sec. 4.5.7.1)

This is a qualifying metal deck diaphragm.

CONNECTIONS

STIFFNESS OF WALL ANCHORS: Anchors of concrete or masonry walls to wood structural elements shall be installed taut and shall be stiff enough to limit the relative movement between the wall and the diaphragm to no greater than one-eighth inch prior to engagement of the anchors. (Tier 2: Sec. 4.6.1.4)

Does not apply to metal deck roofs.


May 2008


TEST CELLS

3.7.9 BASIC STRUCTURAL CHECKLIST FOR BUILDING TYPE C2: CONCRETE SHEAR WALL BUILDINGS WITH RIGID OR STIFF DIAPHRAGMS

C NC N/A COMMENT

BUILDING SYSTEM


Load paths are continuous.


No interior mezzanines.


One story only.


One story only.


One story only.

C3.7.9 Basic Structural Checklist for Building Type C2

These buildings have floor and roof framing that consists of cast-in-place concrete slabs, concrete beams, one-way joists, two-way waffle joists, or flat slabs. Floors are supported on concrete columns or bearing walls. Lateral forces are resisted by cast-in-place concrete shear walls. In older construction, shear walls are lightly reinforced, but often extend throughout the building. In more recent construction, shear walls occur in isolated locations and are more heavily reinforced with boundary elements and closely spaced ties to provide ductile performance. The diaphragms consist of concrete slabs and are stiff relative to the walls. Foundations consist of concrete spread footings or deep pile foundations, or deep foundations.


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No discontinuities from the roof level to the foundations.


One story only.


High number of shear walls throughout small building plan mitigates any concern for torsion due to irregular shear wall layout.


Concrete appeared to be in good condition.

POST-TENSIONING ANCHORS: There shall be no evidence of corrosion or spalling in the vicinity of post-tensioning or end fittings. Coil anchors shall not have been used. (Tier 2: Sec. 4.3.3.5)

Roof is not post-tensioned.

CONCRETE WALL CRACKS: All existing diagonal cracks in wall elements shall be less than 1/8" for Life Safety and 1/16" for Immediate Occupancy, shall not be concentrated in one location, and shall not form an X pattern. (Tier 2: Sec. 4.3.3.9)

Walls appeared to be in good condition with no significant cracks.


COMPLETE FRAMES: Steel or concrete frames classified as secondary components shall form a complete vertical load carrying system. (Tier 2: Sec. 4.4.1.6.1)

Shear walls only.


Highly redundant shear wall layout.

SHEAR STRESS CHECK: The shear stress in the concrete shear walls, calculated using the Quick Check procedure of Section 3.5.3.3, shall be less than the greater of 100 psi or

cf'2 for Life Safety and Immediate Occupancy. (Tier 2: Sec. 4.4.2.2.1)

Shear stresses are very small due to the large number of interior shear walls and continuous perimeter walls.


Wall reinforcing is adequate.


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CONNECTIONS


Shear transfer is via continuous reinforcing between roof diaphragm and walls.


The foundation system is fully integral with the building walls and floor slabs.

3.7.9S SUPPLEMENTAL STRUCTURAL CHECKLIST FOR BUILDING TYPE C2: CONCRETE SHEAR WALL BUILDINGS WITH RIGID OR STIFF DIAPHRAGMS

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DEFLECTION COMPATIBILITY: Secondary components shall have the shear capacity to develop the flexural strength of the components for Life Safety and shall meet the requirements of 4.4.1.4.9, 4.4.1.4.10, 4.4.1.4.11, 4.4.1.4.12, and 4.4.1.4.15 for Immediate Occupancy. (Tier 2: Sec. 4.4.1.6.2)

No significant secondary elements.

FLAT SLABS: Flat slabs/plates not part of lateral-force-resisting system shall have continuous bottom steel through the column joints for Life Safety and Immediate Occupancy. (Tier 2: Sec. 4.4.1.6.3)

All slabs are part of the seismic resisting system.


No coupling beams.

OVERTURNING: All shear walls shall have aspect ratios less than 4 to 1. Wall piers need not be considered. This statement shall apply to the Immediate Occupancy Performance Level only. (Tier 2: Sec. 4.4.2.2.4)

No large aspect ratios.

CONFINEMENT REINFORCING: For shear walls with aspect ratios greater than 2 to 1, the boundary elements shall be confined with spirals or ties with spacing less than 8db.

Wall reinforcing is adequate for minor overturning effects.


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This statement shall apply to the Immediate Occupancy Performance Level only. (Tier 2: Sec. 4.4.2.2.5)


Not an Immediate Occupancy facility.



DIAPHRAGMS

DIAPHRAGM CONTINUITY: The diaphragm shall not be composed of split-level floors and shall not have expansion joints. (Tier 2: Sec. 4.5.1.1)

Diaphragms are continuous.


No significant diaphragm openings.


Adequate reinforcing at all wall to diaphragm connections.



CONNECTIONS


Building founded on continuous wall footings.

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