Tri-Directional Seismic Analysis of an Unreinforced Masonry Building with Flexible Diaphragms
Abstract
To understand the susceptibility that buildings with flexible diaphragm systems have to earthquakes, their seismic response to tri-axial base motions is assessed. The research centers on a tri-directional analytical study of a two-story half-scale unreinforced masonry (URM) structure. The study investigates the effect of tri-axial base motions on response of the structure. It determines how individual component behavior, such as a pier or floor diaphragm, affects the behavior of the entire building system. This project achieves a greater understanding of the tri-directional seismic response of URM building systems with flexible diaphragms. Analysis is conducted on the components of the structure and the building system. The masonry piers and the wood diaphragms are analyzed to determine component behaviors. The building system is analyzed using equivalent static, response spectrum, linear time history, and pushover analysis. Each analysis method includes careful consideration of the directions of load application. Seismic loads are applied independently along each coordinate axis and simultaneously along all three directions. Evaluations of the response of the building system under tri-directional loads found that simultaneous tri-directional seismic motions influence the response of the building system. Maximum responses for two or more directional components can combine to produce a result greater than if a single direction were considered. Furthermore, the interconnectivity of walls in a masonry box building may cause significant changes in wall vertical forces due to global overturning of the building. This change in vertical force and combined base shears can occur simultaneously, leading to significant damage in a building whose lateral resistance is highly dependant on vertical compressive stress. (16 tables, 64 figures, 22 refs.)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 2004
- Accession Number
- ADA429179
Entities
People
- Matthew A. Horney
- Sarah L. Orton
- Steven C. Sweeney
Organizations
- Construction Engineering Research Laboratory