RC牆板厚與邊界柱深相互關係對構架耐震行為之研究

Abstract

鋼筋混凝土構造物因使用需求設置了隔間牆，隔間牆增加了建築物的勁度，導致 地震力放大，又劉德賢研究中得知小尺寸邊界柱搭配隔間牆將使構架失去韌性，總總 的力學行為使隔間牆對構架耐震能力產生不良影響，但實際情況下建築結構中不得不 設置隔間牆。台灣位於地震帶上，必須對隔間牆有更深入的了解，並且找到試圖改變 隔間牆力學行為的方程式。本研究完成四座試體，其中兩座空構架(C35、C20)，另兩 座矩形柱構架填充 RC 隔間牆試體(C50-35W6、C35-50W6)，透過本期及前期[1]試驗結 果發現，含隔間牆構架可承受的側力強度較純構架高，尤其小尺寸構架相差 11 倍之 多，不僅如此，研究的過程中亦發現牆體破壞的順序及形狀為影響構造物韌性的主要 關鍵之一。牆體破壞形狀分為斜角型(X、/、\)、ㄇ 字型以及 U 字型，其中斜角型破壞 為突然性的剪力破壞，工程師應於設計時予以避免;而 ㄇ 字型及 U 字型兩者對於韌 性的差異並不大，但考量使用者的安全性 U 字型破壞因混凝土塊由下方剝落可降低使 用者被混凝土砸傷的可能性而提升安全性，另外不論 ㄇ 字型或 U 字型的破壞都可分 為兩側( 1 )先行脫開，或者上或下(一)先脫開，研究發現若兩側先行脫開，隔間牆破壞 時將較不損及邊界柱，使邊界柱保有完整的構架行為，倘若上方或下方先行脫開，透 過消能能力分析發現，將損及兩倍牆厚的有效柱寬，使得構架無法保有完整的韌性能 力，最大強度點過後將快速衰退。 由以上的發現，為了耐震考量，建議隔間牆可於施工時即進行切削，使破壞形狀 及裂縫順序如預期，不僅可在事先的分析中精準掌握破壞模式，更能透過切削保有構 架的韌性能力，如此一來，建築物可利用隔間牆承受側力強度的能力使小地震發生時 構架物能保持在彈性階段、中地震時僅出現小裂縫，而強震時則強迫牆體與邊界柱脫 開使構架物保有如純構架的韌性能力。

Partition wall is usually required in RC structure in practice to strengthen the stiffness of building, which also increases earthquake energy. As shown in the previous lateral loading test results that small-sized tie-column lose it toughness when the partition wall is allocated, and it also means that many mechanical behaviors lead partition wall damage the seismic capacity of structure. Taiwan situates in Circus-Pacific Seismic Belt, it is necessary to have comprehensive understanding about partition wall and to investigate the relationship between partition wall and other mechanical behaviors. In this research the test program is conducted on four specimen that two are pure frame (C35 and C20) and two are squared infill RC partition wall (C50-35W6 and C35-50W6). It is reveals that a structure with partition wall can endure more than 11 times lateral loading of a pure frame, especially when it compares to small-sized structure. In addition, the sequence and shape of wall destruction are two main factors to affect structure toughness. There are three types of wall destruction, shear type (X shape, / shape and \ shape), ㄇ type and U type. Structural engineers should avoid bevel frame design which usually crack abruptly. In general, there is no difference between ㄇ type and U type on toughness. Considering higher safety, if U type destruction can start from the bottom of the wall, people will not be hurt by RC wall. The destruction of ㄇ type and U type both spilt from left and right side with “I” shape or from top and bottom with “一” shape. In this research, it is found that partition wall destruction may not easily spread to tie-column and tie-column can keep its movement better if the partition wall spilt from top or bottom of the wall. Through Seismic Energy Dissipation Analysis, if partition wall spilt from top or bottom of the wall, effective column width will decrease thickness two times and the frame cannot keep original toughness capacity which will decrease rapidly after passing maximum strength. In conclusion, this research suggests that partition wall can be clipped under construction to make the destruction shape and sequence be predictable. Designer can not only predict the destruction model precisely, also keep frame toughness by clip in advance. Therefore, buildings can have stronger lateral loading force by allocate partition wall, and wall frame can keep its flexibility in light earthquake, small crack occur in moderate earthquake and wall spilt from tie-column in strong earthquake that building structure can keep original toughness capacity like pure frame.