Comparing the Seismic Performance of Conventional and Novel Structural Svstems Usina PBEE

摘要

In recent years, earthquakes have resulted in significant loss of life and damage to structures and infrastructure systems in countries around the Pacific Rim (e.g. Indonesia, Samoa, Chile, and Japan). There are new lateral load resisting systems that are intended to improve the structural performance however a side-by-side comparison of the structural performance, including damage and collapse potential, is rarely made. As such, it is difficult to quantify the seismic advantages of the new system. It is possible to make this comparison using tools developed to advance performance-based earthquake engineering (PBEE) including fragility functions that express the likelihood of damage and reparability, nonlinear analysis methods that capture the full cyclic response of the structural system, and incremental dynamic analyses (IDAs) to evaluate collapse potential. This PBEE tool set was used to compare the seismic performance of a commonly used system to a newly developed system. Specifically the research compares a reinforced concrete (RC) frame with a concrete filled steel tube (CFST) column frame system, which used novel connections specifically developed to reduce structural damage, weight and drift demands. A bridge was selected for the comparison study because the seismic performance of a bridge tends to rely soley on the structure, rather than non-structural elements. The process was as follows: (1) the selected bridge was designed using RC and CFST components, with the objective of having the same strength and stiffness, (2) the structures were subjected to a suite of cnistal and subduction zone motions scaled to represent design (10% probability of exceedance in 50 years) and maximum considered (2% probability of exceedance in 50 years) seismic hazard levels, (3) fragility curves were used to compare the performance of the bridge including damage state as well as maximum and residual drift, and (4) IDAs were conducted to compare the collapse probability. Preliminary results indicate that the CFST structure is more resilient than the RC structure by all measures.