ピロティを有する鉄筋コンクリート造建物の確率論的耐震性能評価

Abstract

本研究では，6 階建てピロティ構造の最大層間変形角に対する年間超過度数，および地震応答がピロティ柱の限界部材角に達する50 年超過確率を検証した。ピロティ構造に対して，典型的な降伏時ベースシヤ係数0.35 のフレーム構造と同等の安全性を確保するには，終局強度型設計指針（日本建築学会，1990）に従って，層降伏時のベースシヤ係数 1.05 の場合に柱の限界変形角 0.02 rad 以上，層降伏時のベースシヤ係数 0.7 の場合は，限界変形角 0.03 rad 以上を確保する必要がある。

This study focuses on the seismic performances of soft-first-story buildings, which are demanded especially in urban areas. Six-story reinforced concrete buildings are focused on, and the seismic responses of the soft-first-story structures and typical frame structures are statistically assessed based on the results of dynamic response analyses. The mean annual frequency of the maximum interstoty drift ratio exceeding the specified value is computed, and the mean annual frequencies for the plural values are shown as a seismic hazard curve for each case. Eventually the probabilities of the maximum interstory drift ratios exceeding safety limit states are computed and compared. The soft-first-story buildings with the yield strength coefficient of more than 0.7 showed the same level of safety in comparison with typical frame structures, on the condition that the same deformation capacities are given to the main structural members.