The Influence of Staircase on the Structure Anti-Seismic Behavior

摘要

The stair is the vertical transport hinge among stories, it becomes a very important component. The design of the existing structures applied to Chinese Code ,the stair is not considered in the overall calculation on different structural systems, such as masonry structure, framework structure and wall structure . the stair is only simplified as an independent structure in design, and the seismic action is also usually not considered. However, the stair is seriously damaged in Wenchuan earthquake, and it failed to perform the role for person escaping in case of emergency. This paper introduces the simplified design method applied to Chinese Code and the damage types of the plate stairs at first. Then , takes a reinforced concrete frame structure with plate stairs as an example, the finite element software is used , there are three cases in analysis as follows:. First, the analysis model is set up without the stairs in consideration; Second, the model is set up with the plate stairs locating at the center of building as part of the overall structure; Third, the model is set up with the plate stairs locating at the ends of building as part of the overall structure. Analysis and calculations were done based on the three cases above, and the focus is on the inherent period ,vibration mode ,total base shear , story drift angle, the internal force distribution of the frame columns and frame beams, the internal force distribution of stairs beams and stairs column, and the stress of the stairway flight. Calculation result shows that plate stairs have a great influence on earthquake resistant behavior of the structure. Designing without the plate staircase in consideration would lead to structural weakness in some columns and cause seriously damage under earthquake and affect the safety of structure.