Evaluation of Modal Pushover–Based Scaling of One Component of Ground Motion: Tall Buildings

2012 ◽  
Vol 28 (4) ◽  
pp. 1469-1493 ◽  
Author(s):  
Erol Kalkan ◽  
Anil K. Chopra
Keyword(s):  
Ground Motions ◽  
Tall Buildings ◽  
Accurate Estimate ◽  
Existing Structures ◽  
History Analysis ◽  
Scaling Procedure ◽  
Response History Analysis ◽  
Performance Based Seismic Design ◽  
Nonlinear Response History Analysis ◽  
Modal Pushover

Nonlinear response history analysis (RHA) is now increasingly used for performance-based seismic design of tall buildings. Required for nonlinear RHAs is a set of ground motions selected and scaled appropriately so that analysis results would be accurate (unbiased) and efficient (having relatively small dispersion). This paper evaluates accuracy and efficiency of recently developed modal pushover– based scaling (MPS) method to scale ground motions for tall buildings. The procedure presented explicitly considers structural strength and is based on the standard intensity measure (IM) of spectral acceleration in a form convenient for evaluating existing structures or proposed designs for new structures. Based on results presented for two actual buildings (19 and 52 stories, respectively), it is demonstrated that the MPS procedure provided a highly accurate estimate of the engineering demand parameters (EDPs), accompanied by significantly reduced record-to-record variability of the responses. In addition, the MPS procedure is shown to be superior to the scaling procedure specified in the ASCE/SEI 7-05 document.

How Many Records Should be used in an ASCE/SEI-7 Ground Motion Scaling Procedure?

2012 ◽  
Vol 28 (3) ◽  
pp. 1223-1242 ◽  
Author(s):  
Juan C. Reyes ◽  
Erol Kalkan
Keyword(s):  
Ground Motions ◽  
Accurate Estimate ◽  
Perfectly Plastic ◽  
History Analysis ◽  
Scaling Procedure ◽  
Response History Analysis ◽  
Nonlinear Response History Analysis ◽  
Structural Responses ◽  
Ground Motion Scaling ◽  
Elastic Perfectly Plastic

U.S. national building codes refer to the ASCE/SEI-7 provisions for selecting and scaling ground motions for use in nonlinear response history analysis of structures. Because the limiting values for the number of records in the ASCE/SEI-7 are based on engineering experience, this study examines the required number of records statistically, such that the scaled records provide accurate, efficient, and consistent estimates of “true” structural responses. Based on elastic–perfectly plastic and bilinear single-degree-of-freedom systems, the ASCE/SEI-7 scaling procedure is applied to 480 sets of ground motions; the number of records in these sets varies from three to ten. As compared to benchmark responses, it is demonstrated that the ASCE/SEI-7 scaling procedure is conservative if fewer than seven ground motions are employed. Utilizing seven or more randomly selected records provides more accurate estimate of the responses. Selecting records based on their spectral shape and design spectral acceleration increases the accuracy and efficiency of the procedure.

Modal Pushover-Based Scaling of Two Components of Ground Motion Records for Nonlinear RHA of Structures

2012 ◽  
Vol 28 (3) ◽  
pp. 1243-1267 ◽  
Author(s):  
Juan C. Reyes ◽  
Anil K. Chopra
Keyword(s):  
Ground Motion ◽  
Nonlinear Response ◽  
Accurate Estimate ◽  
History Analysis ◽  
Response History Analysis ◽  
Nonlinear Response History Analysis ◽  
Small Set ◽  
Ground Motion Records ◽  
Story Building ◽  
Modal Pushover

The modal-pushover-based-scaling (MPS) procedure, currently restricted to scale one component of ground motion records, is extended herein to scale two horizontal components. The accuracy and efficiency of the MPS procedure is evaluated here by applying it to an existing nine-story building, symmetric in plan. The computer model developed for the building is validated against motions of the building recorded during the Chino Hills earthquake (2008). It is demonstrated that nonlinear response history analysis (RHA) of the building for a small set of records scaled by the MPS procedure provided a highly accurate estimate of the engineering demand parameters (EDPs), accompanied by significantly reduced record-to-record variability of the responses. Furthermore, the MPS procedure is shown to be much superior to the procedure specified in the ASCE/SEI 7-05 standard for scaling two components of ground motion records.

scholarly journals Ground motion input for nonlinear response history analysis

2019 ◽  
Vol 52 (3) ◽  
pp. 119-133
Author(s):  
Gareth J. Morris ◽  
Andrew J. Thompson ◽  
James N. Dismuke ◽  
Brendon A. Bradley
Keyword(s):  
Ground Motion ◽  
Nonlinear Response ◽  
Time History ◽  
Tall Buildings ◽  
Nonlinear Time History Analysis ◽  
Existing Buildings ◽  
Ground Motion Selection ◽  
History Analysis ◽  
Response History Analysis ◽  
Nonlinear Response History Analysis

Nonlinear response history analysis (NLRHA), or so-called “nonlinear time history analysis”, is adopted by practicing structural engineers who implement performance-based seismic design and/or assessment procedures. One important aspect in obtaining reliable output from the NLRHA procedure is the input ground motion records. The underlying intention of ground motion selection and amplitude-scaling procedures is to ensure the input for NLRHA is representative of the ground shaking hazard level, for a given site and structure. The purpose of this paper is to highlight the salient limitations of the ground motion selection and scaling requirements in Sections 5.5 and 6.4 of the New Zealand (NZ) loading standard NZS 1170.5 (2004). From a NZ regulatory perspective; there is no specific framework for seismic hazard analysis and ground motion selection (thus self-regulation is the current norm). In contrast, NZS 1170.5 contains many prescriptive requirements for scaling and applying records which are challenging to satisfy in practice. Also discussed within, there are implications for more modern guidance documents in NZ, such as the 2017 “Assessment Guidelines” for existing buildings, which cite NZS 1170.5, a standard which is at least 16 years old (draft issued in 2002). To emphasize the above issues with NZS 1170.5, this paper presents a summary of the more contemporary approaches in the US standards ASCE 7-16 (new buildings) and ASCE 41-17 (existing buildings), along with some examples of the more stringent US requirements for Tall Buildings.

scholarly journals Required Separation to Mitigate Pounding of Adjacent Building Blocks

2018 ◽  
Vol 8 (6) ◽  
pp. 3565-3569
Author(s):  
M. S. Masmoum ◽  
M. S. A. Alama
Keyword(s):  
Nonlinear Response ◽  
Response Spectrum ◽  
Ground Motions ◽  
Building Blocks ◽  
Separation Distance ◽  
Expansion Joints ◽  
History Analysis ◽  
Adjacent Building ◽  
Response History Analysis ◽  
Nonlinear Response History Analysis

This research discusses the feasibility of using the required minimum separation distance based on SBC 301-2007. Moment resistance frames were designed with expansion joints requiring 400mm separation distance. Nonlinear response history analysis was conducted with four ground motions selected and scaled to match the risk-targeted response spectrum of NEOM city based on ASCE 7-16 provisions. An equivalent spring constant value based on floor lateral stiffness was selected as a gap link stiffness. Finally, an evaluation for the pounding response of adjacent blocks is presented along with the conclusions.

Determining Bidirectional Ground Motions for Nonlinear Response History Analysis of Buildings at Far-Field Sites

2018 ◽  
Vol 34 (4) ◽  
pp. 1931-1954 ◽  
Author(s):  
N. Simon Kwong ◽  
Anil K. Chopra
Keyword(s):  
Nonlinear Response ◽  
Current Practice ◽  
Ground Motions ◽  
Computational Effort ◽  
Far Field ◽  
Composite Spectrum ◽  
Multistory Buildings ◽  
History Analysis ◽  
Response History Analysis ◽  
Nonlinear Response History Analysis

The current practice for selecting bidirectional ground motions (GM pairs) to conduct nonlinear response history analysis (RHA) of multistory buildings is restricted to those with a symmetric plan. To overcome such limitations, we propose selecting GM pairs to be consistent with a pair of target spectra defined along the structural axes, enabling a unique azimuth to be determined for each GM pair. We develop two new target spectra: (1) the s-GCMS for two horizontal components of GM and (2) the CMS-UHS Composite Spectrum. Based on nonlinear RHAs of buildings with both symmetric and unsymmetric plans, the CMS-UHS Composite Spectrum is shown to be the best alternative to the current practice of utilizing multiple CMSs, because it provides accurate demands with minimal computational effort and can be easily constructed using existing PSHA tools.

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