"IBC2009E" is a spreadsheet program written in MS-Excel for the purpose of seismic loading analysis for buildings and various nonbuilding structures, as well as architectural, mechanical, and electrical components per the IBC 2009 and ASCE 7-05 Codes.  Specifically, the total base seismic shear for buildings and nonbuilding structures is calculated.  For Multi-Level Buildings, the vertical distribution of the total seismic shear is also determined, and a drift analysis can also be performed..  The seismic restraint force for various components is also calculated.  Seismic maps are also included.

This program is a workbook consisting of thirteen (13) worksheets, described as follows:Worksheet Name DescriptionDoc Documentation sheetSingle-Level Bldg. Seismic base shear for single-level buildingsMulti-Level Bldg. Seismic base shear and vertical shear distribution for multi-level buildingsMulti-Level Bldg. (Drift) Seismic story drift analysis for multi-level buildingsVert. Tank or Vessel Seismic base shear and overturning moment for vertical tanks/vesselsNonbldg. Struct. Seismic base shear for nonbuilding structuresArch. Components Seismic forces for architectural componentsM & E Components Seismic forces for mechanical and electrical components2002 USGS Maps for Ss 2002 USGS maps for 0.2 sec. spectral acceleration with 2% P.E. in 50 yrs.2002 USGS Maps for S1 2002 USGS maps for 1.0 sec. spectral acceleration with 2% P.E. in 50 yrs.ASCE 7-05 Maps for TL ASCE 7-05 Code maps for Long-Period Transition Period2008 USGS Maps for Ss 2008 USGS maps for 0.2 sec. spectral acceleration with 2% P.E. in 50 yrs.2008 USGS Maps for S1 2008 USGS maps for 1.0 sec. spectral acceleration with 2% P.E. in 50 yrs.

 Program Assumptions and Limitations:

1.  This program uses the IBC 2009 Code only to determine the Seismic Design Category, while IBC 2009 Code Section 1613.1 permits the Seismic Design Category to be determined by either IBC 2009 or ASCE 7-05. For all practical purposes, beyond determining the Seismic Design Category, the IBC 2009 Code defers to the ASCE 7-05 Code for seismic analysis and design.2.  This program incorporates the changes provided in Supplement No. 2 to the ASCE 7-05 Code.3.  For buildings, the program assumes the use of the equivalent lateral-force method for analysis, per ASCE 7-05 Section 12.8.   For nonbuilding structures, ASCE 7-05 Section 15.0 is followed.  For architectural, mechanical, and electrical components, ASCE 7-05 Section 13.0 which is followed.  The "simplified" method, per ASCE 7-05 Section 12.14 is not used in any of the calculation worksheets.4.  The program assumes "regular" buildings and structures, with plan and vertical irregularities not being considered.  Refer to ASCE 7-05 Section 12.3 for building configuration, and plan and vertical irregularity criteria.5.  Worksheets for Multi-Level Buildings are applicable for buildings and structures up to 240 feet in height, with up to 15 levels.  (Story deflections are to be determined from separate elastic 2D or 3D frame analysis.)6.  This program does not include the provisions for nonbuilding structures that are supported by other structures as per ASCE 7-05 Section 15.3.7.  Worksheets calculate for "gross" seismic shear force, and do not reflect the use of any load factors.  Refer to ASCE 7-05 Section 12.4 for applicable loads factors for LRFD or strength design as well as ASD analysis.8.  USGS 2002 maps for the short term 0.2 sec. spectral acceleration (SA) with 2% Probability of Exceedance in 50 years, Ss, as well as the 1.0 sec. spectral acceleration (SA) with 2% Probability of Exceedance in 50 years, S1, are included.  These maps are the 2002 "color versions" of  Figures 22-1 and 22-2 from ASCE 7-05.  Peak gravitational acceleration, PGA, is what is experienced by a particle on the ground.  Response spectral acceleration, SA, is what is approximately experienced by a building, as modeled by a particle on a massless vertical rod having the same natural period of vibration as the building.       The SA values shown in the USGS maps as well as the ASCE 7-05 Figures 22-1 through 22-14 are expressed as a percentage of "g", the acceleration due to gravity.  Their numerical values should be divided by 100 to convert them into decimal form for use in the Code formulas and calculations.   Note that there are "exploded" maps of various portions of continental U.S. included as well.  These can be seen by scrolling down screen. (Note: while the USGS does have more current gridded design values for Ss and S1 available at their web site, the user is cautioned in their

use as they are NOT officially adopted for use by the ASCE 7-05 Code.  If their use would result in a lower Seismic Design Category and reduced seismic loads, the user is advised to seek formal approval of their use by the owner and building official if applicable.)     9.  This program allows the user to select only site classes "A" through "E", since site class "F" requires site-specific geotechnical investigation and dynamic site response analyses.  These same requirements also apply for site class "E", but only when Ss >= 1.25*g and S1 >= 0.5*g.10.  In the calculation worksheets, a "hyperlink" is provided to take the user directly to the USGS website at: http://earthquake.usgs.gov/hazards/      Once finished at the USGS website, the user should exit the website by pressing the [<-Back]  button in the top toolbar of the web browser to return to the particular program worksheet.11.  The following "hyperlink" may be used to download the "Earthquake Ground Motion Parameters" calculator tool version 5.1.0 -02/10/2011 from the USGS website:  http://earthquake.usgs.gov/hazards/designmaps/javacalc.php Once installed, this tool will enable the user to determine the Ss and S1 values based on either zip code or latitude/longitude.12.  This program automatically selects the appropriate seismic response modifier, "R", once the type of seismic resisting system has been selected/input by the user.13. This program will automatically alert the user with a "warning message" when any applicable limitations have been exceeded for the particular seismic resisting system selected.14. This program contains numerous “comment boxes” which contain a wide variety of information including explanations of input or output items, equations used, data tables, etc.  (Note:  presence of a “comment box” is denoted by a “red triangle” in the upper right-hand corner of a cell.  Merely move the mouse pointer to the desired cell to view the contents of that particular "comment box".)

Cross Reference Index between IBC 2009 and ASCE 7-05 Codes

Subject IBC 2009 ASCE 7-05Occupancy Category Table 1604.5 Table 1-1Seismic Importance Factor Defers to ASCE 7-05 Table 11.5-1Mapped 0.2 Second Period Spectral Acceleration, Ss Figure 1613.5(1) Figure 22-1Mapped 1.0 Second Period Spectral Acceleration, S1 Figure 1613.5(2) Figure 22-2Site Class Table 1613.5.2 Table 20.3-1Acceleration-based Site Coefficient, Fa Table 1613.5.3(1) Table 11.4-1Velocity-based Site Coefficient, Fv Table 1613.5.3(2) Table 11.4-2Maximum Spectral Response Acceleration, SMS Eqn. 16-37 Eqn. 11.4-1Maximum Spectral Response Acceleration, SM1 Eqn. 16-38 Eqn. 11.4-2Design Spectral Response Acceleration, SDS Eqn. 16-39 Eqn. 11.4-3Design Spectral Response Acceleration, SD1 Eqn. 16-40 Eqn. 11.4-4Seismic Design Category Using SDS and Occupancy Cat. Table 1613.5.6(1) Table 11.6-1Seismic Design Category Using SD1 and Occupancy Cat. Table 1613.5.6(2) Table 11.6-2Building Configuration Defers to ASCE 7-05 Section 12.3.2Permitted Analytical Procedures Defers to ASCE 7-05 Table 12.6-1Seismic Load Effects , E and Em Defers to ASCE 7-05 Section 12.4Redundancy Defers to ASCE 7-05 Section 12.3.4Deflection and Drift Limits Defers to ASCE 7-05 Section 12.12Equivalent Lateral Force Procedure Defers to ASCE 7-05 Section 12.8Seismic Force Resisting Systems Defers to ASCE 7-05 Section 12.2.1Seismic Force Resisting System Coefficients and Factors Defers to ASCE 7-05 Table 12.2-1Architectural, Mechanical, and Electrical Components Defers to ASCE 7-05 Chapter 13Nonbuilding Structures Defers to ASCE 7-05 Chapter 15

Note: Per IBC 2009 Section 1613.1, the Seismic Design Category is permitted to be determined by either the IBC 2009 or ASCE 7-05 Codes.  For all practical purposes, beyond determining the Seismic Design Category, the IBC 2009 Code defers to the ASCE 7-05 Code for seismic analysis and design.

Calculation ReferenceSiesmic Design