مهندسی عمران شریف (Sep 2015)
A COMPARATIVE STUDY AND PROPOSAL FOR ENHANCEMENT OF RAPID SEISMIC EVALUATION OF MASONRY BUILDINGS
Abstract
Among the most suitable methods to obtain building seismic data, in order to specify the level of its seismic ulnerability and prioritize it for undertaking detailed seismic assessment studies, is the use of a qualitative evaluation method. Qualitative evaluation, from this perspective also known as rapid assessment, is usually scheduled for a large number of buildings. Since a huge volume of information has to be collected in such a study, filling special forms and checklists for the studied buildings is necessary. In this paper, considering the great number of masonry buildings and their common weakpoints, this type of building is examined. Two different methodologies, including FEMA154 and Publication No. 376 of the Management and Planning Organization, are used for rapid and detailed evaluation of a large number of school masonry buildings, with emphasis on Publication No. 376, and a detailed study is ccomplished. Actual cases of buildings located in Khuzestan province are considered. The existing condition of these buildings is identified by field surveys and strength-of-material experiments. In addition, two dimensional models of roofs, using the finite element method, and theoretical models for the walls of masonry buildings, are constructed. The joists are modeled with beam elements. For brick arch and joist-and-block roofs, use is made of shell elements. No considerable tensile stresses are observed in the roofs. Then, the lateral loads distributed from the roofs are applied to the walls. For the walls, four failure modes are considered, including mortar joint slippage, overturning, diagonal over-tension, and toe over-compression. It is shown that the rapid and comprehensive evaluation procedures are consistent with Publication No. 376. Moreover, suggestions are offered to modify the fundamental relationship of rapid assessment in Publication No. 376, which leads to evaluation results similar to FEMA154.
