Division D Geotechnical Report - San Antonio
Transcript of Division D Geotechnical Report - San Antonio
CITY OF SAN ANTONIO DIVISION D STINSON MUNICIPAL AIRPORT GEOTECHNICAL REPORT STINSON MONUMENT AND DIRECTIONAL SIGNAGE
DIVISION D
Division D
Geotechnical Report
CITY OF SAN ANTONIO DIVISION D STINSON MUNICIPAL AIRPORT GEOTECHNICAL REPORT STINSON MONUMENT AND DIRECTIONAL SIGNAGE
DIVISION D
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Geotechnical Engineering Study
Stinson Airport Monument and Directional Signage
San Antonio, Texas
Arias Job No. 2016-426
Prepared For
Gonzalez De La Garza
August 22, 2017
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INTRODUCTION................................................................................................................... 1
SCOPE OF SERVICES......................................................................................................... 1
PROJECT DESCRIPTION .................................................................................................... 1
FIELD EXPLORATION.......................................................................................................... 1
LABORATORY TESTING ..................................................................................................... 2
SUBSURFACE CONDITIONS............................................................................................... 2 Geology............................................................................................................................. 2 Site Stratigraphy and Engineering Properties .................................................................... 3 Groundwater...................................................................................................................... 5
DESIGN RECOMMENDATIONS AND DRILLED SHAFT INSTALLATION............................ 5 Potential Expansive Soil Movements ................................................................................. 5 Straight-Shaft Drilled Shafts .............................................................................................. 6 Lateral Pile Capacity.........................................................................................................10 Drilled Shaft Construction Considerations.........................................................................12 IBC Site Classification and Seismic Design Coefficients...................................................14
CONSTRUCTION CRITERIA ...............................................................................................14 Drainage...........................................................................................................................14 Trench Excavations ..........................................................................................................15
GENERAL COMMENTS ......................................................................................................15 Geotechnical Design Review............................................................................................15 Subsurface Variations ......................................................................................................15 Quality Assurance Testing................................................................................................15 Standard of Care ..............................................................................................................16
APPENDIX A: FIGURES AND SITE PHOTOGRAPHS .................................................A-1
APPENDIX B: BORING LOGS AND KEY TO TERMS ..................................................B-1
APPENDIX C: FIELD AND LABORATORY EXPLORATION .........................................C-1
APPENDIX D: GRAIN SIZE DISTRIBUTION CURVES .................................................D-1
APPENDIX E: PLANS AND ELEVATIONS OF MONUMENT SIGNS............................E-1
APPENDIX F: ASFE INFORMATION – GEOTECHNICAL REPORT ............................ F-1
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APPENDIX G: PROJECT QUALITY ASSURANCE .......................................................G-1
TablesTable 1: Generalized Soil Conditions and Soil Properties - Boring B-1 ................................. 3 Table 2: Generalized Soil Conditions and Soil Properties - Boring B-2 ................................. 4 Table 3: Generalized Soil Conditions and Soil Properties - Boring B-3 ................................. 4 Table 4: Groundwater Measurements in Borings.................................................................. 5 Table 5: Drilled Shaft Design Parameters for Axial Loading – Boring B-1............................. 7 Table 6: Drilled Shaft Design Parameters for Axial Loading – Boring B-2............................. 8 Table 7: Drilled Shaft Design Parameters for Axial Loading – Boring B-3............................. 9 Table 8: Geotechnical Input Parameters for Lpile Analyses at Boring B-1 ...........................10 Table 9: Geotechnical Input Parameters for Lpile Analyses at Boring B-2 ...........................11 Table 10: Geotechnical Input Parameters for Lpile Analyses at Boring B-3 .........................12 Table 11: Drilled Shaft Installation Considerations...............................................................13 Table 12: Seismic Design Parameters.................................................................................14
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INTRODUCTION
This report presents the results of a Geotechnical Engineering Study for the proposed Monument and Directional Signs at Stinson Airport in San Antonio, Texas. A Vicinity Map is included as Figure 1 in Appendix A.
This project was authorized by means of Standard Agreement for Professional Services Contract No. 4600014506 (TO-0000020); between Gonzalez De La Garza and Arias Geoprofessionals (Arias), effective May 26, 2016. Our scope of services was performed in general accordance with revised Arias Proposal No. 2016-426, dated June 14, 2016 (revised April 19, 2017).
SCOPE OF SERVICES
The purpose of this geotechnical engineering study was to perform a subsurface exploration and laboratory testing to: (1) establish engineering properties of the subsurface soil and groundwater conditions present on the site and (2) develop drilled shaft foundations design parameters for monument and directional signs.
Environmental studies were not a part of our scope of services. Our scope of work did not include evaluating foundations for walls.
PROJECT DESCRIPTION
Arias previously submitted a geotechnical report dated March 31, 2017 that presented mat foundation and earthwork recommendations for the monument signs at Stinson Municipal Airport in San Antonio, Texas. The Project has since expanded to include directional signsthat are to be supported on drilled shaft foundations. In addition, Arias has been requested to provide recommendations for the support of monument signs on drilled shafts. Landscaping will be installed between the monument sign and the low wall and in front of the low walls.Plans and elevation profiles of monument signs (obtained from project design team) are presented in Appendix E.
FIELD EXPLORATION
Two (2) soil borings were drilled and sampled for monument signs at the approximate locationsshown on the Boring Location Plan provided as Figure 2 in Appendix A. The borings were each drilled to a depth of approximately 15 feet, which was measured from below the existing ground surface on March 1, 2017. Since the project design team requested recommendations for supporting the signs and monuments on drilled piers, we performed additional drilling on July 15, 2017 to extend the previous borings to a depth of 25 feet. At the same time, we drilled a boring to a depth of 25 at the proposed directional sign.
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The borings were sampled in accordance with ASTM D1587 for thin-walled tubes and ASTM D1586 for Split Spoon sampling techniques as described in Appendix C. A truck-mounted drill rig using continuous flight augers together with the sampling tool noted was used to secure the subsurface soil samples.
Soil classifications and borehole logging were conducted during the exploration by one of our field-logging technicians, who is under the supervision of the project Geotechnical Engineer. Final soil classifications, which are presented on the borings logs in Appendix B, were determined based on field observations and the results of laboratory tests performed in accordance with applicable ASTM procedures. After completion of drilling, the open boreholes were backfilled using soil cuttings generated during drilling operations.
LABORATORY TESTING
As a supplement to the field exploration, laboratory testing was conducted to determine soil moisture content, Atterberg Limits, percent passing the US Standard No. 200 sieve andunconfined compressive strength. The laboratory results are reported on the boring logs included in Appendix B, and are plotted as Grain Size Distribution Curves in Appendix D.
A key to the terms and symbols used on the logs is also included in Appendix B. The laboratory testing was done in accordance with applicable ASTM procedures with the specifications and definitions for these tests listed in Appendix C.
Remaining soil samples recovered from this exploration will be routinely discarded following submittal of this report.
SUBSURFACE CONDITIONS
Geology, generalized soil stratigraphy, and groundwater conditions at the project site are discussed in the following sections. The subsurface and groundwater conditions are based on conditions encountered at the boring locations to the depth explored.
GeologyA Geologic Map is included as Figure 3 in Appendix A. The earth materials underlying the project site have been regionally mapped as Fluviatile Terrace Deposits (Qt). Fluviatile Terrace Deposits are alluvial soils consisting of clays and granular soils (i.e. sand or gravel) containing various amounts of clay, silt, sand, and/or gravel. The geotechnical engineering considerations for these types of deposits include the potential for significant variations over short distances and the potential of expansive clays being present.
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Site Stratigraphy and Engineering PropertiesThe general stratigraphic conditions and at the boring locations are provided subsequently in Tables 1, 2 and 3 at Borings B-1, B-2 and B-3, respectively. The presence and thickness of the various subsurface materials can be expected to vary away from and between the exploration locations. The descriptions conform to the Unified Soils Classification System(ASTM D 2487).
Table 1: Generalized Soil Conditions and Soil Properties - Boring B-1
Depth(feet) Material Type PI
RangeNo. 200
Range
N-valueRange
PPRange,
tsfUc
Range
0 to 4SANDY FAT CLAY (CH); very stiff; dark brown to brown; with occasional clayey sand seams
and calcareous material
*39 *44 -- 3.0 to 4.5+ *2.95
4 to 8CLAYEY GRAVEL with sand(GC); dense; light brown and
brown*20 *21 16 - 50 -- --
8 to 10LEAN CLAY (CL); very hard; light
brown *15 *90 *91/10” -- --
10 to 18CLAYEY SAND with gravel (SC);
very dense to medium dense; light brown to brown
-- *27 27 –50/6” -- --
18 to 23SANDY LEAN CLAY (CL); very
stiff; tan *14 -- -- -- --
23 to 25SILTY CLAYEY SAND (SC-SM);
dense; tan and brown *5 34 45 -- --
Where: Depth - Depth from existing ground surface during geotechnical study, feetPI - Plasticity Index, %No. 200 - Passing #200 sieve, %N - Standard Penetration Test (SPT) value, blows per foot or inches if notedUc - Unconfined compressive strength, tsf PP - Pocket Penetrometer Value, tsf* - Only one test performed-- - No Test
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Table 2: Generalized Soil Conditions and Soil Properties - Boring B-2Depth(feet) Material Type PI
RangeNo. 200 Range
N-valueRange
UcRange
0 to 4 SANDY FAT CLAY (CH); very stiff to stiff; dark brown *40 *66 *10 *2.87
4 to 6 CLAYEY GRAVEL with sand (GC);medium dense to dense; tan & brown *20 *22 -- --
6 to 18 CLAYEY SAND with gravel (SC); loose to very dense; brown and tan 18 - 22 30 - 38 3 - 69 --
18 to 23CLAYEY GRAVEL (GC); dense; tan
and brown *43 *40 *45 --
23 to 25FAT CLAY (CH); very stiff; tan and
brown *48 *95 *24 --
Where: Depth - Depth from existing ground surface during geotechnical study, feetPI - Plasticity Index, %No. 200 - Passing #200 sieve, %N - Standard Penetration Test (SPT) value, blows per foot or inches if notedUc - Unconfined compressive strength, tsf * - Only one test performed-- - No Test
Table 3: Generalized Soil Conditions and Soil Properties - Boring B-3
Depth(feet) Material Type PI
RangeNo. 200
Range
N-valueRange
PPRange,
tsfUc
Range
0 to 6 SANDY LEAN CLAY (CL); stiff tohard; dark brown to brown *21 *62 *8 4.0 *6.05
6 to 18CLAYEY SAND with Gravel (SC); medium dense to dense; brown
and tan*24 *24 23 - 41 --
18 to 23SILTY, CLAYEY SAND with
Gravel and (SC-SM); very dense; brown and tan
*4 *30 *71 -- --
23 to 25CLAYEY GRAVEL with sand
(GC); very dense; tan and brown *25 *28 *59 -- --
Where: Depth - Depth from existing ground surface during geotechnical study, feetPI - Plasticity Index, %No. 200 - Passing #200 sieve, %N - Standard Penetration Test (SPT) value, blows per foot or inches if notedPP - Pocket Penetrometer value, tsfUc - Unconfined compressive strength, tsf * - Only one test performed-- - No Test
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GroundwaterA dry soil sampling method was used to obtain the soil samples at the project site. Groundwater was not encountered during the drilling of Borings B-1 and B-2 on March 1, 2017. However, groundwater was observed in all three borings during our drilling on July 15, 2017. A summary of groundwater information is presented in the following table.
Table 4: Groundwater Measurements in Borings
Boring No.Groundwater Depths (feet)
During Drilling After Completion
B-1 24.0 23.2
B-2 23.0 22.8
B-3 23.3 22.8
Note: Depth is measured from existing ground surface at the time of drilling on July 15, 2017.
Groundwater levels will often change significantly over time and should be verified immediately prior to construction. Water levels in open boreholes may require several hours to several days to stabilize depending on the permeability of the soils. Groundwater levels at this site may differ during construction because fluctuations in groundwater levels can result from seasonal conditions, rainfall, drought, or temperature effects. Pockets or seams of gravels, sands, silts or open fractures and joints can store and transmit “perched” groundwater flow or seepage. Should dewatering become necessary during construction, it is considered “means and methods” and is solely the responsibility of the Contractor.
DESIGN RECOMMENDATIONS AND DRILLED SHAFT INSTALLATION
Potential Expansive Soil MovementsThe dark brown sandy fat clay (CH), which was encountered in borings B-1 and B-2 to a depth of about 4 feet, has high shrink-swell characteristics. The dark brown sandy lean clay (CL), which was encountered in boring B-3 to a depth of about 4 feet, has moderate shrink-swell characteristics. Expansive clay materials shrink when they lose water and swell or grow in volume when they gain water content. The potential of expansive soils to shrink and swell is related to the Plasticity Index (PI). Clayey soils with a higher PI have a greater potential for soil volume changes due to moisture content variations. Change in soil moisture is the single most important factor affecting the shrinking and swelling of clays. The most pronounced movements are commonly observed when soils are exposed to extreme moisture fluctuations that occur between drought conditions and wet seasons.
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At Borings B-1 and B-2, we estimate the potential vertical rise (PVR) to be about 2½ inchesat Borings B-1 and B-2 and about 2 inches at boring B-3 using the Tex-124-E method outlined by the Texas Department of Transportation (TXDOT). This method provides an estimate of the PVR using the liquid limits, plasticity indices, and existing water contents.
The PVR is estimated in the seasonally active zone, which is assumed to be 15 feet based upon assumed changes in soil moisture content from a dry to a wet condition. However, soil movements in the field depend on the actual changes in moisture content. Thus, actual soil movements could be less than that calculated if little soil moisture variations occur, or the actual movement could exceed the estimated values if actual soil moisture content changes exceed the assumed dry and wet limits outlined by the PVR method. Such moisture conditions that deviate from the limits of the PVR method may be the result of extended droughts, flooding, perched groundwater infiltration, poor surface drainage, and/or leaking irrigation lines.
Straight-Shaft Drilled ShaftsThe monument and directional signs are expected to transmit relatively light axial compression loading to the proposed straight-sided drilled shafts. The drilled shafts will also be subject to: (1) lateral loading; and (2) tension loading due to wind-induced uplift forces and potential uplift loading induced on the upper 4 feet of the shafts due to expansive soil-related heaving. Accordingly, the drilled shafts will need to be anchored adequately below the zone of seasonal moisture change to resist uplift loading.
Drilled shafts should be designed in accordance with the allowable side friction (i.e. compression and tension loading) and end bearing values given subsequently in Tables 5, 6, and 7 at Borings B-1, B-2, and B-3, respectively. The design methodology for developing allowable values and associated factors of safety together with other pertinent information is provided in the “Notes” given below the tables.
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Table 5: Drilled Shaft Design Parameters for Axial Loading – Boring B-1
Depth (feet) Material
Recommended Design ParametersAllowable
Skin Friction psf
Allowable End
Bearing psf
Uplift Forcekips
0 - 4 Very Stiff SANDY FAT CLAY Neglect ---
20*D
4 - 8 Medium Dense to Dense CLAYEY GRAVEL with SAND 500 ---
8 -10 Very Hard LEAN CLAY 1,000 --
10 - 18 Very Dense to Medium Dense CLAYEY SAND with GRAVEL 800 --
18 - 23 Very Stiff to Hard SANDY LEAN CLAY 800 9,000
23 - 25 Dense SILTY CLAYEY SAND 500 10,000
Constraints to be Imposed During Pier Design
Minimum embedment depth 20 feet(See note 2)
Minimum Spacing Center to Center 3 shaft diameters
Minimum shaft diameter 18 inches
Notes:1. The depths provided are below the existing ground surface at the time of the borings.
2. Shafts should be a minimum diameter of 18 inches, and be spaced a minimum of 3 shaft diameters center to center. The minimum embedment depth of 20 feet was selected to anchor the drilled shaftssufficiently below the expansive clay, which has the potential to impose uplift forces due to soil heaving. If shafts are extended to depths greater than 20 feet, there is a progressively risk for encountering groundwater, which was measured at a depth of about 23 feet at the time of the borings.
3. Shaft capacities were evaluated based on design methodologies included in FHWA-IF-99-025 - Drilled Shafts: Construction Procedures and Design Methods. Both end bearing and side friction resistance may be used in evaluating the allowable bearing capacity of the pier shafts for the strata shown above.Recommended design parameters include a factor of safety of 2 for skin friction and of 3 for end bearing.For compression loading, frictional resistance is neglected in the upper 4 feet and for a length equal to 1 pier diameter from the bottom of the shaft.
4. The uplift force in kips resulting from expansion of soils in the active zone may be computed using the above formula where D is the shaft diameter in feet. Uplift resistance along the shaft can be used from a depth of 4 feet to the bottom of the shaft. Sustained dead loads will also aid in resisting uplift forces.
5. Sufficient reinforcing steel should be placed within the pier to account for tension and lateral loading as applicable. Vertical steel should be a minimum of 1% of the gross cross-sectional area of the shaft; however, the final reinforcing requirements should be determined by the project structural engineer. Tensile rebar steel should be designed in accordance with ACI Code Requirements.
6. Total and differential settlement of drilled shafts is expected to be less than 1 inch and ½ inch, respectively. Estimated settlements are based on performance of properly installed piers in the South Texas areas. A detailed settlement estimate is outside of the scope of this service.
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Table 6: Drilled Shaft Design Parameters for Axial Loading – Boring B-2
Depth (feet) Material
Recommended Design ParametersAllowable
Skin Friction psf
Allowable End
Bearing psf
Uplift Forcekips
0 - 4 Very Stiff to Stiff SANDY FAT CLAY Neglect ---
20*D
4 - 6 Medium Dense to Dense CLAYEY GRAVEL with SAND 400 ---
6 - 13 Loose CLAYEY SAND with GRAVEL 200
13 -18 Very Dense CLAYEY SAND with GRAVEL 800 --
18 - 23 Dense CLAYEY GRAVEL with SAND 800 12,000
23 - 25 Very Stiff FAT CLAY 800 9,000
Constraints to be Imposed During Pier Design
Minimum embedment depth 20 feet(See note 2)
Minimum Spacing Center to Center 3 shaft diameters
Minimum shaft diameter 18 inches
Notes:1. The depths provided are below the existing ground surface at the time of the borings.
2. Shafts should be a minimum diameter of 18 inches, and be spaced a minimum of 3 shaft diameters center to center. The minimum embedment depth of 20 feet was selected to anchor the drilled shaftssufficiently below the expansive clay, which has the potential to impose uplift forces due to soil heaving. If shafts are extended to depths greater than 20 feet, there is a progressively risk for encountering groundwater, which was measured at a depth of about 23 feet at the time of the borings.
3. Shaft capacities were evaluated based on design methodologies included in FHWA-IF-99-025 - Drilled Shafts: Construction Procedures and Design Methods. Both end bearing and side friction resistance may be used in evaluating the allowable bearing capacity of the pier shafts for the strata shown above.Recommended design parameters include a factor of safety of 2 for skin friction and of 3 for end bearing.For compression loading, frictional resistance is neglected in the upper 4 feet and for a length equal to 1 pier diameter from the bottom of the shaft.
4. The uplift force in kips resulting from expansion of soils in the active zone may be computed using the above formula where D is the shaft diameter in feet. Uplift resistance along the shaft can be used from a depth of 4 feet to the bottom of the shaft. Sustained dead loads will also aid in resisting uplift forces.
5. Sufficient reinforcing steel should be placed within the pier to account for tension and lateral loading as applicable. Vertical steel should be a minimum of 1% of the gross cross-sectional area of the shaft; however, the final reinforcing requirements should be determined by the project structural engineer. Tensile rebar steel should be designed in accordance with ACI Code Requirements.
6. Total and differential settlement of drilled shafts is expected to be less than 1 inch and ½ inch, respectively. Estimated settlements are based on performance of properly installed piers in the South Texas areas. A detailed settlement estimate is outside of the scope of this service.
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Table 7: Drilled Shaft Design Parameters for Axial Loading – Boring B-3
Depth (feet) Material
Recommended Design ParametersAllowable
Skin Friction psf
Allowable End
Bearing psf
Uplift Forcekips
0 - 6 Stiff to Hard SANDY FAT CLAY Neglect ---
20*D6 -18 Medium Dense to Dense CLAYEY SAND with GRAVEL 600 --
18 - 23 Very Dense SILTY, CLAYEY SAND with GRAVEL 800 12,000
23 - 25 Very Dense CLAYEY GRAVEL with SAND 800 12,000
Constraints to be Imposed During Pier Design
Minimum embedment depth 20 feet(See note 2)
Minimum Spacing Center to Center 3 shaft diameters
Minimum shaft diameter 18 inches
Notes:1. The depths provided are below the existing ground surface at the time of the borings.
2. Shafts should be a minimum diameter of 18 inches, and be spaced a minimum of 3 shaft diameters center to center. The minimum embedment depth of 20 feet was selected to anchor the drilled shaftssufficiently below the expansive clay, which has the potential to impose uplift forces due to soil heaving. If shafts are extended to depths greater than 20 feet, there is a progressively risk for encountering groundwater, which was measured at a depth of about 23 feet at the time of the borings.
3. Shaft capacities were evaluated based on design methodologies included in FHWA-IF-99-025 - Drilled Shafts: Construction Procedures and Design Methods. Both end bearing and side friction resistance may be used in evaluating the allowable bearing capacity of the pier shafts for the strata shown above.Recommended design parameters include a factor of safety of 2 for skin friction and of 3 for end bearing.For compression loading, frictional resistance is neglected in the upper 4 feet and for a length equal to 1 pier diameter from the bottom of the shaft.
4. The uplift force in kips resulting from expansion of soils in the active zone may be computed using the above formula where D is the shaft diameter in feet. Uplift resistance along the shaft can be used from a depth of 4 feet to the bottom of the shaft. Sustained dead loads will also aid in resisting uplift forces.
5. Sufficient reinforcing steel should be placed within the pier to account for tension and lateral loading as applicable. Vertical steel should be a minimum of 1% of the gross cross-sectional area of the shaft; however, the final reinforcing requirements should be determined by the project structural engineer. Tensile rebar steel should be designed in accordance with ACI Code Requirements.
6. Total and differential settlement of drilled shafts is expected to be less than 1 inch and ½ inch, respectively. Estimated settlements are based on performance of properly installed piers in the South Texas areas. A detailed settlement estimate is outside of the scope of this service.
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Lateral Pile CapacityLateral pile analyses including capacity, maximum shear, and maximum bending moment will be evaluated by the project structural engineer using Lpile or similar software. In Tables 8 to10 given subsequently, Arias presents geotechnical input parameters for the encountered soils in Borings, B-1, B-2 and B-3, respectively. The depths to the top and bottom of each layer were interpreted using data developed at the explored boring locations and layer boundaries as shown on the logs for the respective borings.
Table 8: Geotechnical Input Parameters for Lpile Analyses at Boring B-1
Depth(ft)
MaterialLPILE SoilType
e CuK
Static e50
0 - 4 Very Stiff SANDY FAT CLAY 3 0.069 6.94 0 250 0.009
4 - 8Medium Dense to Dense CLAYEY
GRAVEL with SAND4 0.069 0 32 90 --
8 -10 Very Hard LEAN CLAY 3 0.072 27.8 -- 1,000 0.005
10 - 18Very Dense to Medium Dense CLAYEY SAND
with GRAVEL4 0.072 -- 32 225 --
18 - 23 Very Stiff to Hard SANDY LEAN CLAY 3 0.072 27.8 0 1,000 0.005
23 - 25 Dense SILTY CLAYEY SAND 4 0.036 0 32 125 --
Where: e = effective soil unit weight, pci
cu = undrained soil shear strength, psi= undrained angle of internal friction, degrees
K = modulus of subgrade reaction, pcie50 = 50% strain value
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Table 9: Geotechnical Input Parameters for Lpile Analyses at Boring B-2
Depth(ft)
MaterialLPILE Soil Type
e CuK
Static e50
0 - 4 Very Stiff to Stiff SANDY FAT CLAY 3 0.069 6.94 0 250 0.009
4 - 6Medium Dense to Dense CLAYEY
GRAVEL with SAND4 0.069 0 32 125 --
6 - 13 Loose CLAYEY SAND with GRAVEL 4 0.066 0 28 25 --
13 -18 Very Dense CLAYEY SAND with GRAVEL 4 0.072 -- 32 225 --
18 - 23 Dense CLAYEY GRAVEL with SAND 4 0.072 0 32 175 --
23 - 25 Very Stiff FAT CLAY 3 0.036 17.4 -- 750 0.006
Where: e = effective soil unit weight, pci
cu = undrained soil shear strength, psi= undrained angle of internal friction, degrees
K = modulus of subgrade reaction, pcie50 = 50% strain value
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Table 10: Geotechnical Input Parameters for Lpile Analyses at Boring B-3
Depth(ft)
MaterialLPILE Soil Type
e CuK
Static e50
0 - 6 Stiff to Hard SANDY FAT CLAY 3 0.069 6.94 0 250 0.009
6 -18Medium Dense to
Dense CLAYEY SAND with GRAVEL
4 0.069 0 32 125 --
18 - 23Very Dense SILTY, CLAYEY SAND with
GRAVEL4 0.072 0 32 225 --
23 - 25 Very Dense CLAYEY GRAVEL with SAND 4 0.036 0 32 125 --
Where: e = effective soil unit weight, pci
cu = undrained soil shear strength, psi= undrained angle of internal friction, degrees
K = modulus of subgrade reaction, pcie50 = 50% strain value
Drilled Shaft Construction Considerations
It is important to note that very hard clay dense to very dense clayey sand and clayey gravel was encountered in the boring locations. Thus, high-torque drilling equipment will likely be required for the drilled shaft construction. Additionally, sloughing may occur due to the presence of granular soils and ground water. The Contractor should be prepared for such conditions.
The Contractor should verify groundwater conditions before production drilled shaft installation begins. Comments pertaining to high-torque drilling equipment, groundwater, slurry, and temporary casing are based on conditions encountered at the locations of Borings B-1 to B-3. Conditions at individual drilled shaft locations may differ from those presented and may require that these issues be implemented to successfully install the shafts. Construction considerations for drilled shafts are outlined in the following table.
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Table 11: Drilled Shaft Installation Considerations
Recommended installation procedure USACE refers to FHWA(FHWA-NHI-10-016, May 2010)
High-torque drilling equipment anticipated Yes
Groundwater anticipated Yes
Temporary casing anticipated
Yes; extent depends upon subsurface soil and groundwater conditions encountered during
construction. Casing anticipated to be extended through water-bearing gravel, sand and clay soils;
and sufficiently into the underlying relatively impervious layer to achieve an adequate seal.
Please note that very stiff fat clay was encountered at 23 feet in Boring B-2. However,
this low permeability stratum was not encountered to the explored depths in B-1 and B-3. If
temporary casing is required, and an impermeable layer is not encountered to seal the casing,
Contractor may need to use slurry method for drilled shaft installation.
Slurry installation anticipatedYes, if casing is needed and a seal cannot be achieved in the relatively impervious layer as
noted above.
Concrete placement
Same day as drilling. If the excavation cannot be drilled and filled with concrete on the same day,
temporary casing or slurry may be needed to maintain an open excavation.
Maximum water accumulation in excavation 2 inches
Concrete installation method needed if water accumulates
Tremie or pump to displace water
Quality assurance monitoring
Geotechnical Engineer’s representative should be present during drilling of all shafts, should observe drilling and document the installed depth, should
confirm and document the bearing material type at the base of excavation and cleanliness of base, and should observe placement of steel rebars.
The following installation techniques will aid in successful construction of the drilled shafts:
The clear spacing between rebar or behind the rebar cage should be at least 3 times the maximum size of coarse aggregate.
Centralizers on the rebar cage should be installed to keep the cage properly positioned.
Cross-bracing of a reinforcing cage may be used when fabricating, transporting, and/or lifting. However, experience has shown that cross-bracing can contribute to the development of voids in a concrete shaft. Therefore, we recommend the removal of the cross-bracing prior to lowering the cage in the open shaft.
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The use of a tremie should be employed so that concrete is directed in a controlled manner down the center of the shaft to the shaft bottom. The concrete should not be allowed to ricochet off the pier reinforcing steel nor off the side walls.
The concrete should be designed to achieve the desired design strength when placed at a 7-inch slump, plus or minus 1-inch tolerance. Adding water to a mix designed for a lower slump does not meet these recommendations.
IBC Site Classification and Seismic Design CoefficientsSection 1613 of the International Building Code (2015) requires that every structure be designed and constructed to resist the effects of earthquake motions, with the seismic design category to be determined in accordance with Section 1613 or ASCE 7. Site classification using the International Building Code (2015) is based on the soil profile encountered to the 100-foot depth. The stratigraphy at the site location was explored to a maximum 25-foot depth.
The clays and granular soils having similar consistency were extrapolated to be present between 25 and 100-foot depths. Based on the site class definitions included in Table 1613.5.2 and 1613.5.5 of the 2015 Code and the encountered generalized stratigraphy, we characterize the site as Site Class D.
Seismic design coefficients were determined using the on-line software, Seismic Hazard Curves and Uniform Response Spectra, version 5.1.0, dated February 10, 2011 accessed at (http://earthquake.usgs.gov/hazards/designmaps/javacalc.php). Analyses were performed considering the 2015 International Building Code. Input included Site Coordinate (29.342639,-98.471292) and Site Class D. Seismic design parameters for the site are summarized in the following table.
Table 12: Seismic Design Parameters
Site Classification Fa Fv Ss S1
D 1.6 2.4 0.085g 0.029g
Where: Fa = Site coefficientFv = Site coefficientSs = Mapped spectral response acceleration for short periodsS1 = Mapped spectral response acceleration for a 1-second period
CONSTRUCTION CRITERIA
DrainageGood positive drainage during and after construction is very important to reduce soil volume changes that can detrimentally affect the performance of the planned monuments. Proper attention to surface and subsurface drainage details during the design and construction phase of development can aid in preventing many potential soil related problems during and following the completion of the project.
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Arias Geoprofessionals 15 Arias Job No. 2016-426
Trench ExcavationsExcavations should comply with OSHA Standard 29CFR, Part 1926, Subpart P and all State of Texas and local requirements. A trench is defined as a narrow excavation in relation to its depth. In general, the depth is greater than the width, but the bottom width of the trench is not greater than 15 feet. Trenches greater than 5 feet in depth require a protective system such as trench shields, trench shoring, or sloping back the excavation side slopes.
GENERAL COMMENTS
This report was prepared as an instrument of service for this project exclusively for the use of Gonzalez De La Garza and the project design team. If the development plans change relative to layout or if different subsurface conditions are encountered during construction, we should be informed and retained to ascertain the impact of these changes on our recommendations. We cannot be responsible for the potential impact of these changes if we are not informed.Important information about this geotechnical report is provided in the ASFE publication included in Appendix F.
Geotechnical Design ReviewArias should be given the opportunity to review the design and construction documents. The purpose of this review is to check to see if our geotechnical recommendations are properly interpreted into the project plans and specifications. Please note that design review was notincluded in the authorized scope and additional fees may apply.
Subsurface VariationsSoil and groundwater conditions may vary away from the sample boring locations. Transition boundaries or contacts, noted on the boring logs to separate soil types, are approximate. Actual contacts may be gradual and vary at different locations. The Contractor should verify that similar conditions exist throughout the proposed area of excavation. If different subsurface conditions or highly variable subsurface conditions are encountered during construction, we should be contacted to evaluate the significance of the changed conditions relative to our recommendations.
Quality Assurance TestingThe long-term success of the project will be affected by the quality of materials used for construction and the adherence of the construction to the project plans and specifications. As Geotechnical Engineer of Record (GER), we should be engaged by the Owner to provide Quality Assurance (QA) testing. Our services will be to evaluate the degree to which constructors are achieving the specified conditions they’re contractually obligated to achieve, and observe that the encountered materials during earthwork for foundation installation are consistent with those encountered during this study. In the event that Arias is not retained to provide QA testing, we should be immediately contacted if differing subsurface conditions are encountered during construction. Differing materials may require modification to the
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Arias Geoprofessionals 16 Arias Job No. 2016-426
recommendations that we provided herein. A message to the Owner with regard to the project QA is provided in the ASFE publication included in Appendix G.
Arias has an established in-house laboratory that meets the standards of the American Standard Testing Materials (ASTM) specifications of ASTM E-329 defining requirements for Inspection and Testing Agencies for soil, concrete, steel and bituminous materials as used in construction. We maintain soils, concrete, asphalt, and aggregate testing equipment to provide the testing needs required by the project specifications. All of our equipment is calibrated by an independent testing agency in accordance with the National Bureau of Standards. In addition, Arias is accredited by the American Association of State Highway & Transportation Officials (AASHTO), the United States Army Corps of Engineers (USACE) and the Texas Department of Transportation (TxDOT), and also maintains AASHTO Materials Reference Laboratory (AMRL) and Cement and Concrete Reference Laboratory (CCRL) proficiency sampling, assessments and inspections.
Furthermore, Arias employs a technical staff certified through the following agencies: the National Institute for Certification in Engineering Technologies (NICET), the American Concrete Institute (ACI), the American Welding Society (AWS), the Precast/Prestressed Concrete Institute (PCI), the Mine & Safety Health Administration (MSHA), the Texas Asphalt Pavement Association (TXAPA) and the Texas Board of Professional Engineers (TBPE). Our services are conducted under the guidance and direction of a Professional Engineer (P.E.) licensed to work in the State of Texas, as required by law.
Subgrade preparation and fill placement operations should be observed and tested by the Geotechnical Engineer or his/her representative. As a guideline, a minimum of 3 tests should be performed per lift. Any areas not meeting the required compaction should be recompacted and retested until compliance is met.
Standard of CareSubject to the limitations inherent in the agreed scope of services as to the degree of care and amount of time and expenses to be incurred, and subject to any other limitations contained in the agreement for this work, Arias has performed its services consistent with that level of care and skill ordinarily exercised by other professional engineers practicing in the same locale and under similar circumstances at the time the services were performed.
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APPENDIX A: FIGURES AND SITE PHOTOGRAPHS
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142 Chula Vista, San Antonio, Texas 78232Phone: (210) 308-5884 • Fax: (210) 308-5886
VICINITY MAPStinson Airport Monument Signage
San Antonio, Texas
Date: August 2, 2017 Job No.: 2016-426 Figure 11 of 1
Drawn By: RWL Checked By: GKApproved By: JS Scale: N.T.S.
Approximate Site Locations
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142 Chula Vista, San Antonio, Texas 78232Phone: (210) 308-5884 • Fax: (210) 308-5886
BORING LOCATION PLANStinson Airport Monument Signage
San Antonio, Texas
Date: August 2, 2017 Job No.: 2016-426REVISIONS: Drawn By: RWL Checked By: GKNo.: Date: Description: Approved By: SAH Scale: N.T.S.
Figure 21 of 1
ITEM 2016-426
PORTION OF GEOLOGIC ATLAS OF TEXAS
(San Antonio Sheet)LEGEND
Symbol Name AgeQt Fluviatile Terrace Deposits Quaternary Period / HolooceneEwi Wilcox Group Tertiary Period / EoceneEmi Midway Group Tertiary Period / EoceneQle Leona Formation Quaternary Period / Pleitoscene
Fault Segment with Indication of Relative Movement
142 Chula Vista, San Antonio, Texas 78232Phone: (210) 308-5884 • Fax: (210) 308-5886
GEOLOGIC MAPStinson Monument Signage Design
San Antonio, Texas
Date: August 2, 2017 Job No.: 2016-426 Figure 31 of 1
Drawn By: RWL Checked By: GKApproved By: CMS Scale: N.T.S.
U D
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Arias Geoprofessionals B-1 Arias Job No. 2016-426
APPENDIX B: BORING LOGS AND KEY TO TERMS
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GW
GP
GM
GC
SW
SP
SM
SC
ML
CL
MH
CH
Massive or Weakly Bedded Limestones
Mor
e th
an h
alf o
f mat
eria
l SM
ALLE
R
than
No.
200
Sie
ve s
ize
FOR
MA
TIO
NA
L M
ATE
RIA
LS
GROUP SYMBOLS
KEY TO TERMS AND SYMBOLS USED ON BORING LOGS
CO
AR
SE-G
RA
INED
SO
ILS
GR
AVE
LSSA
ND
S
Mor
e th
an H
alf o
f Coa
rse
fract
ion
is
LAR
GER
than
No.
4 S
ieve
siz
e
Mor
e th
an h
alf o
f mat
eria
l LAR
GER
than
No.
200
Sie
ve s
ize
MAJOR DIVISIONS
Silty Gravels, Gravel-Sand-Silt Mixtures
Poorly-Graded Gravels, Gravel-Sand Mixtures, Little or no Fines
Well-Graded Gravels, Gravel-Sand Mixtures, Little or no Fines
DESCRIPTIONS
Clayey Sands, Sand-Clay Mixtures
Silty Sands, Sand-Silt Mixtures
Poorly-Graded Sands, Gravelly Sands, Little or no Fines
Well-Graded Sands, Gravelly Sands, Little or no FinesC
lean
Gra
vels
(li
ttle
or n
o Fi
nes)
Gra
vels
with
Fi
nes
(App
reci
able
am
ount
of F
ines
)
Cle
an S
ands
(li
ttle
or n
o Fi
nes)
Sand
s w
ith F
ines
(A
ppre
ciab
le
amou
nt o
f Fin
es)
Liqu
id L
imit
less
th
an 5
0Li
quid
Lim
it gr
eate
r tha
n 50
LIMESTONE
MARLSTONE
SANDSTONE
Clayey Gravels, Gravel-Sand-Clay Mixtures
Massive Sandstones, Sandstones with Gravel Clasts
Inorganic Clays of High Plasticity, Fat Clays
Inorganic Silts, Micaceous or Diatomaceous Fine Sand or Silty Soils, Elastic Silts
Inorganic Clays of Low to Medium Plasticity, Gravelly Clays, Sandy Clays, Silty Clays, Lean Clays
Inorganic Silts & Very Fine Sands, Rock Flour, Silty or Clayey Fine Sands or Clayey Silts with Slight Plasticity
Indurated Argillaceous Limestones
Indicates Final Observed Groundwater Level
Indicates Initial Observed Groundwater Location
Cretaceous Clay Deposits
Massive or Poorly Bedded Chalk Deposits
Mudstone or Massive Claystones
FIN
E-G
RA
INED
SO
ILS
Mor
e th
an h
alf o
f Coa
rse
fract
ion
is
SMAL
LER
than
No.
4 S
ieve
siz
e
SILT
S &
C
LAYS
SILT
S &
C
LAYS
GROUNDWATER
MARINE CLAYS
CHALK
CLAYSTONE
Very Dense
30 - 50
Over 50
10 - 30
Consistency and Strength of Cohesive Soils
Number of Blows per ft., N
Unconfined Compressive
Strength, qᵤ (tsf)Consistency
Density of Granular Soils
Relative Density
Very Loose
Number of Blows per ft.,
N0 - 4
4 - 10 Loose
Medium
Dense
Below 2
2 - 4 Soft
Very Soft
Stiff
Less than 0.25
0.25 - 0.5
0.5 - 1.0
1.0 - 2.0
Medium (Firm)
Very Stiff
Hard
4 - 8
8 - 15
15 - 30
Over 30 Over 4.0
2.0 - 4.0
SP
SW
Arias GeoprofessionalsITEM 2016-426
Group Symbol
GW(Less than 5% finesC )
Cu < 4 and/or GP[Cc < or Cc > 3]D
Gravels with Fines GM(More than 12% finesC )
GC
Sands Clean Sands SW(Less than 5% finesH ) Cu < 6 and/or SP
[Cc < or Cc > 3]D
Sands with Fines SM(More than 12% finesH )
SC
Silts and Clays inorganic CL
ML
organic OL
Silts and Clays inorganic CH
MH
organic OH
HIGHLY ORGANIC SOILS PTA Based on the material passing the 3-inch (75mm) sieveB If field sample contained cobbles or boulders, or both, add "with cobbles or boulders, or both" to group nameC Gravels with 5% to 12% fines require dual symbols:
GW-GM well-graded gravel with siltGW-GC well-graded gravel with clayGP-GM poorly-graded gravel with siltGP-GC poorly-graded gravel with clay
D Cu = D60/D10 Cc =
E If soil contains ≥ 15% sand, add "with sand" to group nameF If fines classify as CL-ML, use dual symbol GC-GM, or SC-SMG If fines are organic, add "with organic fines" to group nameH Sand with 5% to 12% fines require dual symbols:
SW-SM well-graded sand with siltSW-SC well-graded sand with claySP-SM poorly-graded sand with siltSP-SC poorly-graded sand with clay
I If soil contains ≥ 15% gravel, add "with gravel" to group nameJ If Atterberg limits plot in hatched area, soil is a CL-ML, silty clayK If soil contains 15% to < 30% plus No. 200, add "with sand" or "with gravel," whichever is predominantL If soil contains ≥ 30% plus No. 200, predominantly sand, add "sandy" to group nameM If soil contains ≥ 30% plus No. 200, predominantly gravel, add "gravelly" to group nameN PI ≥ 4 and plots on or above "A" lineO PI < 4 or plots below "A" lineP PI plots on or above "A" lineQ PI plots below "A" line
TERMINOLOGY
Boulders Over 12-inches (300mm) Parting Inclusion < 1/8-inch thick extending through samplesCobbles 12-inches to 3-inches (300mm to 75mm) Seam Inclusion 1/8-inch to 3-inches thick extending through sampleGravel 3-inches to No. 4 sieve (75mm to 4.75mm) Layer Inclusion > 3-inches thick extending through sampleSand No. 4 sieve to No. 200 sieve (4.75mm to 0.075mm)Silt or Clay Passing No. 200 sieve (0.075mm)Calcareous Containing appreciable quantities of calcium carbonate, generally nodular
Stratified Alternating layers of varying material or color with layers at least 6mm thickLaminated Alternating layers of varying material or color with the layers less than 6mm thickFissured Breaks along definite planes of fracture with little resistance to fracturingSlickensided Fracture planes appear polished or glossy sometimes striatedBlocky Cohesive soil that can be broken down into small angular lumps which resist further breakdownLensed Inclusion of small pockets of different soils, such as small lenses of sand scattered through a mass of clayHomogeneous Same color and appearance throughout
(D30)2
D10 x D60
KEY TO TERMS AND SYMBOLS USED ON BORING LOGSTABLE 1 Soil Classification Chart (ASTM D 2487-11)
Group NameB
Organic ClayK,L,M,N
Organi SiltK,L,M,O
Fat ClayK,L,M
Clayey GravelE,F,G
Well-Graded SandI
Poorly-Graded SandI
Silty SandF,G,I
Clayey SandF,G,I
Well-Graded GravelE
Poorly-Graded GravelE
Silty GravelE,F,G
Soil ClassificationCriteria of Assigning Group Symbols and Group Names Using Laboratory TestsA
More than 50% retained on No. 200 sieve
FINE-GRAINED SOILS
COARSE-GRAINED SOILS
Primarily organic matter, dark in color, and organic odor
Liquid limit less than 50
Liquid limit 50 or more
PI > 7 and plots on or above "A" lineJ
PI < 4 or plots below "A" lineJ
PI plots on or above "A" linePI plots on or below "A" line
Fines classify as CL or CH
(50% or more of coarse fraction passes No. 4 sieve)
50% or more passes the No. 200 sieve
Cu ≥ 4 and 1 ≤ Cc ≤ 3DGravels Clean Gravels
Elastic SiltK,L,M
Organic ClayK,L,M,P
Organic SiltK,L,M,Q
Peat
Lean ClayK,L,M
SiltK,L,M
Fines classify as CL or CH
Cu ≥ 6 and 1 ≤ Cc ≤ 3D
Fines classify as ML or MH
(More than 50% of coarse fraction retained on No. 4 sieve)
Fines classify as ML or MH
<0.75
<0.75
Liquid limit - oven driedLiquid limit - not dried
Liquid limit - oven driedLiquid limit - not dried
Arias GeoprofessionalsITEM 2016-426
Arias Geoprofessionals C-1 Arias Job No. 2016-426
APPENDIX C: FIELD AND LABORATORY EXPLORATION
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Arias Geoprofessionals C-2 Arias Job No. 2016-426
FIELD AND LABORATORY EXPLORATION
The field exploration program included drilling at selected locations within the site and intermittently sampling the encountered materials. The boreholes were drilled using single flight auger (ASTM D 1452). Samples of encountered materials were obtained using a split-barrel sampler while performing the Standard Penetration Test (ASTM D 1586), or using a thin-walled tube sampler (ASTM D 1587). The sample depth interval and type of sampler used is included on the soil boring log. Arias’ field representative visually logged each recovered sample and placed a portion of the recovered sampled into a plastic bag for transport to our laboratory.
SPT N values and blow counts for those intervals where the sampler could not be advanced for the required 18-inch penetration are shown on the soil boring log. If the test was terminated during the 6-inch seating interval or after 10 hammer blows were applied used and no advancement of the sampler was noted, the log denotes this condition as blow count during seating penetration.
Arias performed soil mechanics laboratory tests on selected samples to aid in soil classification and to determine engineering properties. Tests commonly used in geotechnical exploration, the method used to perform the test, and the column designations on the boring log where data are reported are summarized as follows:
Test Name Test Method Log DesignationWater (moisture) content of soil and rock by mass ASTM D 2216 WC
Liquid limit, plastic limit, and plasticity index of soils ASTM D 4318 PL, LL, PI
Amount of material in soils finer than the No. 200 sieve ASTM D 1140 -200
Unconfined Compressive Strength of Soil ASTM D 2166 Uc
The laboratory results are reported on the soil boring log.
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APPENDIX D: GRAIN SIZE DISTRIBUTION CURVES
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APPENDIX E: PLANS AND ELEVATIONS OF MONUMENT SIGNS
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Arias Geoprofessionals F-1 Arias Job No. 2016-426
APPENDIX F: ASFE INFORMATION – GEOTECHNICAL REPORT
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Arias Geoprofessionals G-1 Arias Job No. 2016-426
APPENDIX G: PROJECT QUALITY ASSURANCE
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8811 Colesville Road Suite G106 Silver Spring, Maryland 20910 Voice: 301.565.2733 Fax: 301.589.2017 E-mail: [email protected] Internet: www.asfe.org
PROJECT QUALITY ASSURANCE
1
Construction materials engineering and testing (CoMET) consultants perform quality-assurance (QA) services to evaluate the degree to which constructors are achieving
obligated to achieve. Done right, QA can save you time and money; prevent unanticipated-conditions claims, change orders, and disputes; and reduce short-term and long-term risks, especially by detecting molehills before they grow into mountains.
follow bad advice; e.g., “CoMET consultants are all the same. They all have accredited
standard QA scope of service, meaning that – must propose
the cheapest QA service it can live with, jeopardizing service quality and aggravating risk for the entire project team. Besides, the advice is based on misinformation.
Fact: , and the quality of those that are varies
important – nonetheless means that a facility
others just barely scrape by. And what an accrediting body typically evaluates – management, staff, facilities, and equipment – can change substantially before the next review, two, three, or more years from now.
Fact: Many have no
organizations of questionable merit, while not for
– want you to believe that price is the only
of course. Firms that sell low price typically lack the facilities, equipment, personnel, and
achieve the reliability concerned owners need to achieve quality in quality assurance.
A Message to Owners
Done right, QA can save you time and
money; prevent claims and disputes; and
reduce risks.
right because they follow bad advice.
are not accredited.
CoMET
ITEM 2016-426
PROJECT QUALITY ASSURANCE
To derive maximum value from your
project manager to serve actively on the project team from beginning to end, a level
planning and design stages, experienced CoMET professionals can help the design
and establish appropriate observation, testing, and instrumentation procedures and protocols. They can also analyze plans and specs much as constructors do, looking for the little errors,
become the basis for big extras and big claims. They can provide guidance about operations that need closer review than others, because of their criticality or potential for error or abuse. They can also relate their experience with the various constructors that have expressed interest in your project.
services focus on two distinct issues: those that relate to geotechnical engineering and those that relate to the other elements of construction.
The geotechnical issues are critically important because they are essential to the “observational method” geotechnical
They apply the observational method by developing a sampling plan for a project, and
samples are properly obtained, packaged, and transported. The engineers review the samples and, typically, have them tested in their own laboratories. They use the information they
and develop preliminary recommendations
like excavations, site grading, foundation-bearing grades, and roadway and parking-lot preparation and surfacing.
their recommendations until they or
to verify that
the subsurface conditions the engineers
predicted are those that actually exist.
When unanticipated conditions are observed,
Responding to client requests, many
able to perform overall construction QA, encompassing – in addition to geotechnical issues – reinforced concrete, structural steel,
all CoMET consultants are alike, some owners take bids for the overall CoMET package,
someone other than the geotechnical engineer
Firms that sell low price typically lack the facilities, equipment, personnel,
concerned owners need to achieve quality in quality assurance.
To derive maximum value, require the project manager to
serve actively on the project team from beginning to end.
2ITEM 2016-426
3
PROJECT QUALITY ASSURANCE
a project site, to brief them on what to look for and where, when, and how to look. (
, because no one else
issues.) And once they arrive at a project site,
about what they observe, because they regard
operations is almost always penny-wise and pound-foolish. Still, because owners are given
explain why
To derive the biggest bang for the QA buck, identify three or even four quality-focused
available free at www.asfe.org.) Ask about
clients and client representatives involved;
Insist upon receiving
licenses, and insurance coverages.
Once you identify the two or three most
preferably at their own facility, so you can inspect their laboratory, speak with management and technical staff, and form an opinion about
manager participate in the meeting. You will
experienced personnel who are familiar with the codes and standards involved and know how to:
perform the necessary observation, inspection, and testing;
respond to the unexpected.
Important: Many of the services CoMET QA
operations and outcomes – require the good judgment afforded by extensive training and experience, especially in situations where standard operating procedures do not apply. You need to know who will be exercising that judgment: a 15-year “veteran” or a rookie?
on site to verify that the subsurface conditions they predicted are those that
actually exist.
the geotechnical engineer of record (GER)
always penny-wise and pound-foolish, helping to explain
why “geo” issues are the number-one source of construction-
industry claims and disputes.
ITEM 2016-426
4
PROJECT QUALITY ASSURANCE
Also consider the tools CoMET personnel
calibration; others, less so. Passion is a good
not current, be cautious. You cannot trust test
about their reporting practices, including report
of nonconformance, and how they resolve complaints.
the constructor to pay for CoMET services. so you
fund QA via the constructor, have the CoMET fee included as an allowance in the bid documents. This arrangement ensures that you
prevents the CoMET fee from becoming part of
that the International Building Code (IBC) for Special Inspection
(SI) services commonly performed by the CoMET consultant as a service separate from
Because failure to comply could result in denial of an occupancy or use permit, having a contractual agreement that conforms to the IBC mandate is essential.)
constructor, have the CoMET fee included as
an allowance in the bid documents. Note,
too, that the International Building Code
(IBC) requires the owner to pay for Special
Inspection (SI) services.
CoMET consultants can usually quote their fees as unit fees, unit fees with estimated total (invoiced on a unit-fee basis), or lump-sum (invoiced on a percent-completion basis
which method is used, estimated quantities
their total-fee estimates by using quantities they know are too low and then request change orders long before QA is complete.
Once you and the CoMET consultant settle on the scope of service and fee, enter into a written
own contracts; most owners sign them. Some owners prefer to use different contracts, but that can be a mistake when the contract was prepared for construction services. Professional
Wholly avoidable problems occur when a contract includes
involved and fail to include those that do.
Many of the services
require good judgment.
is needed to deal promptly
with the unanticipated.
Some owners create wholly avoidable
problems by using a contract prepared for
construction services.
ITEM 2016-426
8811 Colesville Road Suite G106 Silver Spring, Maryland 20910 Voice: 301.565.2733 Fax: 301.589.2017 E-mail: [email protected] Internet: www.asfe.org
PROJECT QUALITY ASSURANCE
QA for owners, not constructors. While constructors are commonly allowed to review QA reports as a courtesy, you need to make it clear that constructors do not have a legal right to rely on those reports; i.e., if constructors want to forgo their own observation and testing and rely on results derived from a scope created to meet only the needs of the owner, they
. In all too many cases where owners have not made that clear, some constructors have alleged that they did have a legal right to rely on QA reports and, as a result, the CoMET consultant – not they – are responsible for their failure to deliver what they contractually promised to provide. The outcome can be delays and disputes that entangle you and all other principal project
that possesses the resources and attitude needed to manage this and other risks as an element
early. Keep it engaged. And listen to what the CoMET consultant says. A good CoMET consultant can provide great value.
For more information, speak with your ASFE-Member CoMET consultant or contact ASFE directly.
5ITEM 2016-426