SPECTRAL RESPONSE ACCELERATION PARAMETER AT SHORT PERIODĪ. MAPPED RISK TARGETED MAXIMUM CONSIDERED EARTHQUAKE (MCE R) VALUES OF SITE COEFFICIENT, F a a Site Class The numbers relevant to this blog post are highlighted in the F v table below. These revisions mirrored the same revisions making their way through the update process of the 2016 edition of ASCE 7, which was also ongoing at the time. The 2018 IBC incorporated the following revisions to the values of site coefficients F a and F v during its update process. In this blog, we will discuss that error and its resolution. In the course of making this revision, a significant error also crept in, which eventually had to be corrected in Supplement 1 to ASCE 7-16. That changed in the 2018 edition of the IBC and the 2016 edition of ASCE 7, where the values of both coefficients were revised in major ways in order to make them consistent with the seismic maps included in ASCE 7-10 (based on 2008 USGS maps) and ASCE -16 (based on 2014 USGS maps). The values were based on studies following the Mexico earthquake of 1985 and the Loma Prieta earthquake of 1989. They have, in fact, remained the same since they were first introduced in the 1994 edition of the Uniform Building Code. Data necessary for selection of acceptance criteria are provided.For seismic design in accordance with the IBC and ASCE 7 provisions, the values of site coefficients, F a and F v, have remained the same over the last several editions of the IBC and ASCE 7. Proposed modeling parameters show improved fit with experimental data over existing parameters. Median rather than conservative estimates of non-linear modeling parameters were produced to achieve “best” estimates of structural behavior. A database of 490 column tests was compiled for this project.
This study is a part of ACI 369 committee’s effort.Įxisting provisions for non-linear analysis are re-assessed in this study for both rectangular and circular reinforced concrete columns. Task to update current ASCE 41-06 provisions pertaining to RC structures is now handled by ACI (American Concrete Institute) committee 369 entitled “Seismic Repair and Rehabilitation”. Different levels of conservatism were used throughout the standard to produce modeling parameters for different structural elements, which leads to inconsistencies at the system level. The American Society of Civil Engineers (ASCE) Standard 41-06 Supplement No.1 (2007) assists engineers in modeling and evaluating the non-linear behavior of structures till collapse.
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