| dc.description.abstract | Reinforced coupled wall systems are one of the efficient lateral resistance systems for earthquakes. A coupled wall system consists of two or more wall piers connected by link or coupling beams. The coupled walls, relative to individual walls, have increased energy dissipation and increased structure stiffness. In the past, a few test studies of planar coupled walls with low or medium-rise structures showed that the behavior of coupling beams, high axial loads of wall piers, and the degree of coupling can significantly affect the performance. Simulation studies demonstrated that designs developed with performance-based design (PBD) could further improve the response of coupled walls.
Performance-based design is based in part on determining the probability of experiencing different types of loss under several potential earthquakes. Accurate damage estimation is significantly crucial to PBD. In general, experimental data can be used to provide information to estimate the damage of the structures. Unfortunately, since the limited test data of coupled walls do not provide a sufficient breadth of knowledge and experiments of various coupled wall configurations, it is difficult to predict the damage progression of coupled walls. Numerical simulation is an alternative method to overcome the limitations. The focus of prior simulation studies of coupled walls has primarily focused on global responses, with details of the damage progression receiving limited attention. Therefore, this dissertation conducted simulations that, in addition to contributing additional data about the global response, focused on identifying the damage progression.
A frame model was used to simulate the nonlinear behavior of the coupled walls. The wall piers and coupling beams in the frame model were beam-column elements with fiber sections; material regularization was used. The models were validated and shown to predict reasonable damage progression of the coupled wall compared to the test results.
Six 16-story reinforced concrete coupled walls were designed to explore the behavior of the coupled wall. The cases involve two configurations of planar and non-planar coupled walls with three degrees of coupling (i.e., 40%, 50%, and 60%). Planar coupled wall designs consisted of two typical rectangular wall piers with coupling beams. Non-planar coupled wall designs consisted of two C-shaped wall piers with coupling beams. Seismic behavior was simulated with both nonlinear static and nonlinear dynamic analyses in the simulation tool of OpenSees (Open System for Earthquake Engineering Simulation).
The simulation results provide sufficient information to evaluate the damage progression of coupled walls. The coupled wall with a low degree of coupling showed several advantages over those with a high degree of coupling. The degree of coupling significantly affects the behavior of coupled walls, including the response (e.g., drift and rotation), yielding mechanism, and the damage progression. The study recommended an appropriate degree of coupling from 40% to 50% for the design of reinforced concrete coupled walls.
Finally, the study developed fragility functions for reinforced concrete coupled walls with wall piers and coupling beams based on the simulation data. The proposed fragility function provides a useful tool to estimate the damage information of the coupled walls. | en |
