鋼骨梁柱接頭耐震行為研究

Abstract

1994年美國北嶺地震對鋼骨構造建築造成大量損壞，甚多鋼骨梁柱接頭在尚未充分發揮韌性能力前便已破壞，故對於梁翼銲接梁腹鎖螺栓之標準型式梁柱接頭有必要進行檢討與修正。改良型式梁柱接頭的開發皆是針對標準梁柱接頭之缺點而進行改善，故從研究標準梁柱接頭之行為及破壞模式出發，以作為改良型式接頭發展之基礎。 本研究進行兩組實尺寸梁翼銲接梁腹鎖螺栓標準接頭試體試驗。梁翼全滲透銲接採用較高韌性衝擊值之銲材，並遵循銲接程序，以改善銲接品質。試驗過程在梁端施加反覆荷重以模擬地震力作用下之情形，藉以瞭解標準接頭之韌性行為及破壞模式，試驗結果兩組試體之塑性轉角分別為0.0187及0.0242弧度，破壞模式均是在扇形開孔處產生初始裂縫，進而往翼寬方向拉裂而破壞。為了更精確的瞭解梁柱接頭區之應力分佈，進行有限元素分析，各迴圈載重位移關係均和實驗值相當吻合。試驗及分析的結果均顯示，扇形開孔處因幾何形狀不連續，將會產生應力集中情形，導致初始裂縫的發生。最後所建議之改良型式接頭經由分析皆能降低梁柱接面之應力需求，可作為改善標準型式接頭之參考。

The 1994 Northridge earthquake caused widespread and unexpected damage to the standard connections of moment resisting frames. Numerous bolted web-welded flange connections to be having brittle failure before fully developing ductility to dissipate energy. This research presents the results of standard connections tests, as the fundamental background to develop the improved connections. The experimental research was conducted to study the ultimate moment strength, ductility performance and plastic rotation of bolted web-welded flange connections. Tests of two large-scale specimens were conducted on single cantilever assemblage subjected to cyclic loads. Weld metal with adequate notch toughness was used in full-penetration welding. In order to evaluate the stress distribution and performance of various types of connections, the finite element analysis was utilized. Experimental and analytical study demonstrated the geometric discontinuity of assess-hole caused the initial crack because of stress concentration. The improved types of connections suggested by analytical study can reduce the stress demand of column face effectively