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A Hybrid-Parallel Framework for the Nonlinear Seismic Analysis of Very Tall Buildings

Citation

Dizon, Abel Bermie Roberto (2016) A Hybrid-Parallel Framework for the Nonlinear Seismic Analysis of Very Tall Buildings. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Z96Q1V58. http://resolver.caltech.edu/CaltechTHESIS:12142015-083607823

Abstract

FRAME3D, a program for the nonlinear seismic analysis of steel structures, has previously been used to study the collapse mechanisms of steel buildings up to 20 stories tall. The present thesis is inspired by the need to conduct similar analysis for much taller structures. It improves FRAME3D in two primary ways.

First, FRAME3D is revised to address specific nonlinear situations involving large displacement/rotation increments, the backup-subdivide algorithm, element failure, and extremely narrow joint hysteresis. The revisions result in superior convergence capabilities when modeling earthquake-induced collapse. The material model of a steel fiber is also modified to allow for post-rupture compressive strength.

Second, a parallel FRAME3D (PFRAME3D) is developed. The serial code is optimized and then parallelized. A distributed-memory divide-and-conquer approach is used for both the global direct solver and element-state updates. The result is an implicit finite-element hybrid-parallel program that takes advantage of the narrow-band nature of very tall buildings and uses nearest-neighbor-only communication patterns.

Using three structures of varied sized, PFRAME3D is shown to compute reproducible results that agree with that of the optimized 1-core version (displacement time-history response root-mean-squared errors are ~〖10〗^(-5) m) with much less wall time (e.g., a dynamic time-history collapse simulation of a 60-story building is computed in 5.69 hrs with 128 cores—a speedup of 14.7 vs. the optimized 1-core version). The maximum speedups attained are shown to increase with building height (as the total number of cores used also increases), and the parallel framework can be expected to be suitable for buildings taller than the ones presented here.

PFRAME3D is used to analyze a hypothetical 60-story steel moment-frame tube building (fundamental period of 6.16 sec) designed according to the 1994 Uniform Building Code. Dynamic pushover and time-history analyses are conducted. Multi-story shear-band collapse mechanisms are observed around mid-height of the building. The use of closely-spaced columns and deep beams is found to contribute to the building's “somewhat brittle” behavior (ductility ratio ~2.0). Overall building strength is observed to be sensitive to whether a model is fracture-capable.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:nonlinear analysis, seismic analysis, structural analysis, parallel structural analysis, parallel implicit analysis, parallel computing, building collapse, tall building collapse, very tall building collapse, hybrid-parallel computing, FRAME3D, PFRAME3D
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Civil Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Hall, John F.
Thesis Committee:
  • Heaton, Thomas H. (chair)
  • Hall, John F.
  • Asimaki, Domniki
  • Kochmann, Dennis M.
Defense Date:1 December 2015
Funders:
Funding AgencyGrant Number
Harold Hellwig FoundationUNSPECIFIED
George Housner FellowshipUNSPECIFIED
Record Number:CaltechTHESIS:12142015-083607823
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:12142015-083607823
DOI:10.7907/Z96Q1V58
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9321
Collection:CaltechTHESIS
Deposited By: Abel Bermie Dizon
Deposited On:14 Dec 2015 22:54
Last Modified:18 May 2017 17:11

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