비정형 건물의 비틀림효과를 반영한 비구조요소의 설계 지진하중 산정

Abstract

The design code specifies the seismic loads for non-structural components (NSC) regardless of their planar locations. Thus, structures with irregular geometry that exhibit torsional behavior may experience greater seismic loads than those specified by the design code. This study assessed the adequacy of the code-specified equivalent static loads using nonlinear dynamic analysis results from structures intentionally designed to be eccentric, and finally proposed a formula that accounts for torsional amplification effects in buildings. The analysis results indicated that the code-specified equivalent static loads were conservative in the lower stories or near the center of mass. On the other hand, the dynamic analysis-based loads exceeded the equivalent static load in the outer perimeter of the mid- and upper stories. Accordingly, a torsional amplification factor equation was proposed, which is a function of the building's eccentricity ratio and the relative distance from the center of mass. The proposed equation applies to the NSC installed in the stories above the midpoint of the total building height. For a building with zero eccentricity or NSC at the center of mass, the function was set to unity.