擴柱補強校舍之耐震檢核與側推分析

Abstract

民國88年發生的921地震，反映出國中小校舍耐震能力普遍不足之問題，各方學者對此亦提出對應之補強方法，其中，擴柱修復補強經驗證，可同時提高結構之強度與韌性，為一良好補強方法；本研究針對擴柱修復補強後結構，以試驗結果驗證現行規範在軟層、弱層、強柱弱梁、柱破壞模式及接頭等檢核對擴柱補強後結構之適用性。按照現行規範檢核所得結果，在軟層、強柱弱梁及接頭這三項理論檢核皆與試驗結果互相符合，但於弱層的檢核卻與試驗結果不同，且柱破壞模式的檢核流程也不符既有校舍結構之行為。針對擴柱補強後結構支柱破壞模式檢核，本文提出修正方法，經修正後，理論檢核與試驗結果互相符合且合理，而弱層則有待深入研究。 結構經擴柱修復補強後，試體破壞機制由弱柱強梁轉換為強柱弱梁，鑒於現有簡易側推分析乃建立於弱柱強梁之假設，若經擴柱補強，簡易側推分析之結果則會造成勁度與強度的高估，故文中以傾角撓度法提出修正，讓分析結構不需受限於弱柱強梁或強柱弱梁；最後將手算側推分析結果，佐以ETABS分析與試驗結果進行比對，驗證SD pushover可適用於強柱弱梁試體。

Lots of elementary and secondary school buildings were damaged by the devastating 921 Chi-Chi earthquake, so scholars proposed retrofit methods for increasing the seismic performance of school buildings, and the retrofit method by RC jacketing system at columns can increase ductility and strength of buildings. In this thesis, the criteria for the prediction of soft story, weak story, strong-column-weak-beam, column failure mode and joint failure for buildings retrofitted by jacketing column are studied based on experimental data. The criteria for the prediction of weak story and column failure mode need to modify so that they are more logical and consistent with the experimental results. After retrofitting by jacketing column, the building failure mode has been strong-column-weak-beam. Considering the simplified pushover analysis is based on the strong-beam-weak-column building, it is not suitable for strong-column-weak-beam buildings because the stiffness and strength would be overestimated. Therefore, simplified pushover is improved by slope-deflection method so that pushover is limited to the strong-beam-weak-column building. After compared with ETABS analysis and experimental results, slope-deflection pushover is a suitable method for strong-beam-weak-column buildings.