RC牆體偏心配置之含牆構架牆板厚度與邊界柱深相互間關係對面內耐震行為研究

Abstract

過去研究結果在街屋或校舍結構之含RC牆構架、EERI & IAEE之低矮型圍束砌體建築耐震設計規範、RC牆板後與邊界柱深相互關係之耐震行為顯示，皆有在邊界柱深於牆厚比一定比值下，牆板裂縫延續至邊界構材之現象，使得邊界構材一併喪失獨立抗彎構架行為，均強調牆體須納入考慮耐震能力之行為。 我國耐震設計規範要求牆體需一併納入結構分析計算，然而現行工程師除了符合剪力牆要求外，其餘牆體均忽略不算。國內集合住宅式高樓建築物內，為了增加使用空間，使用許多隔間牆、隔戶牆與外牆等，採用柱中心與牆版中心合一配置與牆板邊與柱邊合一偏心配置，過去研究多數針對柱中心與牆版中心合一之非結構RC牆之探討，對於牆板邊與柱邊合一偏心配置無相關性探討，此構行為是否與柱中心與牆版中心合一之非結構RC牆相近，須進一步探討以釐清現行工程師忽略非結構RC牆體之設計合理性。 本研究共規劃四座縮尺50%試體進行試驗，一座為純牆試體；另三座為填充6公分RC牆構架，邊界構材均採用方形柱，尺寸為50公分、35公分及20公分，分別模擬高樓建築、中高樓建築及低矮樓層建築。本研究結果顯示，柱深對牆厚比越小，構架之韌性越差，極限強度後仍保有純構架之行為不明顯，且因RC牆體偏心配置，導致邊界構材有受力傳遞不均勻且不對稱破壞現象，其極限強度較柱中心與牆版中心合一之非結構RC牆體配置低約10~20%。

As shown in the lateral loading test results of the town house or school building structure with RC wall frame , in“Seismic Design Guide for Low-Rise Confined Masonry Buildings” by EERI & IAEE and“Influence of Relativity between RC Wall Thickness and Tie-Columns Depth on the Seismic Behavior of Frame with Infill RC Wall”, all that failure occurred with diagonal cracks propagated through the walls and the tie-columns, where tie-columns depth was under certain proportion. Analysis from failure envelopes reveals that the tie-column failed to fulfill its role as a solely moment-resisting element due to it shear inability. These results shows walls need to be included in the structural capacity. Although the seismic specifications require that the walls need to be included in the structural analysis, engineers usually ignore RC walls except shear walls in their calculation. Taiwan apartment-type building uses RC frame with eccentric walls and non-eccentric walls to partition space. Most previous studies explored non-structureal RC walls and columns aligned center of center, but less than explored the case with side to side alignment where the wall is eccentric to the columns but one surface of the wall and the columns is in the same plane. Rationality of ignoring RC walls except shear walls is further investigated. In this research, four 50% reduced scale specimens, one pure wall and the other three with 6cm infill eccentric RC wall, were tested. The columns of these three frames are all square with depth 50cm, 35cm and 20cm respectively. It is shown in the test results that the toughness of the frame decreases and the retained pure frame behavior post-strength become less obvious with increase of the column depth/ wall thickness ratio. Eccentric walls configuration causes the to fail in asymmetric way because of the eccentric force induced by the wall. Also strength decreases by 10 to 20% compared with non-eccentric walls configuration.