dc.contributor.author	Spears, Paul Wesley	en
dc.contributor.committeechair	Charney, Finley A.	en
dc.contributor.committeemember	Plaut, Raymond H.	en
dc.contributor.committeemember	Murray, Thomas M.	en
dc.contributor.department	Civil Engineering	en
dc.date.accessioned	2014-03-14T21:36:36Z	en
dc.date.adate	2004-06-15	en
dc.date.available	2014-03-14T21:36:36Z	en
dc.date.issued	2004-05-18	en
dc.date.rdate	2004-06-15	en
dc.date.sdate	2004-05-25	en
dc.description.abstract	This thesis presents the results of basically two separate studies. The first study involved identifying structural and earthquake parameters that influenced seismic structural collapse. The parameter study involved nonlinear dynamic analyses using single-degree-of-freedom (SDOF) bilinear models. Four parameters were associated with the SDOF models — the lateral stiffness, the post-yield stiffness ratio, the yield strength, and the stability ratio (P-Delta effects). Then, three parameters were associated with the ground motions — the records themselves, the lateral ground motion scales, and the vertical ground motion scales. From the parameter study, it was found that the post-yield stiffness ratio augmented by P-Delta effects (rp) in conjunction with the ductility demand was the best predictor of collapse. These two quantities include all four structural parameters and the seismic displacement demands. It was also discovered in the parameter study that vertical accelerations did not significantly influence lateral displacements unless a given combination of model and earthquake parameters was altered such that the model was on the verge of collapsing. The second study involved Incremental Dynamic Analysis (IDA) using bilinear SDOF models representative of low rise buildings in both the Western United States (WUS) and the Central and Eastern United States (CEUS). Models were created that represented three, five, seven, and nine story buildings. Five sites from both the WUS and CEUS were used. Four different damage measures were used to assess the performance of the buildings. The IDA study was primarily interested in the response of the structures between the earthquake intensities that have a 10 percent probability of occurring in 50 years (10/50) and 2 percent probability of occurring in 50 years (2/50). The results showed that all structures could be in danger of severe damage and possible collapse, depending on which damage measure and which earthquake was used. It is important to note, though, that the aforementioned is based on a damage-based collapse rule. The damage-based rule results were highly variable. Using an intensity-based collapse rule, proved to be more consistent. Due to the nature of the bilinear models, only those structures with negative rp values ever collapsed using an intensity-based collapse rule. Most of the WUS models had positive rp values and many of the CEUS models had negative rp values. While many of the CEUS structures had negative rp values, which made them prone to collapse, most of the CEUS structures analyzed did not collapse at the 2/50 intensity. The reason was that the periods of the CEUS models were much longer than the approximate periods that were required to determine the strengths. Consequently, the strength capacity of most of the CEUS models was much greater than the seismic strength demands. While many of the CEUS models did have sudden collapses due to the large negative rp values, the collapses happened at intensities that were generally much higher than the 2/50 event. In the IDA, it was also shown that vertical accelerations can significantly affect the ductility demands of a model with a negative rp post-yield stiffness ratio as the earthquake intensity approaches the collapse intensity. Since IDA is concerned with establishing collapse limit states, it seems that the most accurate collapse assessments would include vertical accelerations.	en
dc.description.degree	Master of Science	en
dc.identifier.other	etd-05252004-150156	en
dc.identifier.sourceurl	http://scholar.lib.vt.edu/theses/available/etd-05252004-150156/	en
dc.identifier.uri	http://hdl.handle.net/10919/42793	en
dc.language.iso	en	en
dc.publisher	Virginia Tech	en
dc.relation.haspart	App_C3_Residual_Displacements_v_rp.pdf	en
dc.relation.haspart	Vita.pdf	en
dc.relation.haspart	App_A_Accelerograms.pdf	en
dc.relation.haspart	App_B_Comparative_RH.pdf	en
dc.relation.haspart	App_C1.1_Collapse_v_Stability_Ratio.pdf	en
dc.relation.haspart	App_D1_CEUS_IDA_Figures.pdf	en
dc.relation.haspart	Thesis.pdf	en
dc.relation.haspart	App_C1.2_Collapse_v_Post_Yield_Stiffness_Ratio.pdf	en
dc.relation.haspart	App_C1.3_Collapse_v_Yield_Force.pdf	en
dc.relation.haspart	App_D2_WUS_IDA_Figures.pdf	en
dc.relation.haspart	App_C1.4_Collapse_Due_to_Vert_Accel.pdf	en
dc.relation.haspart	App_C2_Ductility_Demand_v_rp.pdf	en
dc.rights	In Copyright	en
dc.rights.uri	http://rightsstatements.org/vocab/InC/1.0/	en
dc.subject	Dynamic Instability	en
dc.subject	Incremental Dynamic Analysis	en
dc.subject	Nonlinear Analysis	en
dc.subject	Seismic Hazard	en
dc.subject	Central and Eastern United States	en
dc.subject	P-Delta Effects	en
dc.subject	Vertical Accelerations	en
dc.subject	OpenSees	en
dc.subject	Collapse	en
dc.title	Parameters Influencing Seismic Structural Collapse with Emphasis on Vertical Accelerations and the Possible Related Risks for New and Existing Structures in the Central and Eastern United States	en
dc.type	Thesis	en
thesis.degree.discipline	Civil Engineering	en
thesis.degree.grantor	Virginia Polytechnic Institute and State University	en
thesis.degree.level	masters	en
thesis.degree.name	Master of Science	en

Parameters Influencing Seismic Structural Collapse with Emphasis on Vertical Accelerations and the Possible Related Risks for New and Existing Structures in the Central and Eastern United States

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