高強度鋼管混凝土柱之耐震行為

Abstract

本研究以試驗方式，探討鋼管混凝土柱之強度與韌性行為。藉由九根鋼管混凝土柱試體，針對混凝土抗壓強度、鋼板厚度、與加勁處理（縱向加勁板、剪力釘、無加勁）等各項試驗變數，於承受固定軸力與模擬水平地震力作用時，探討其對鋼管混凝土柱試體結構行為之影響。 實驗結果顯示，鋼管混凝土柱於初始加載階段，外觀上並無異狀，隨著側向水平變形愈來愈大，於鋼管混凝土柱試體受壓側發生局部挫屈，鋼板漸漸鼓起，最後導致銲道開裂。同時鋼板局部挫屈皆發生於鋼板降伏之後，顯示鋼管混凝土柱中鋼材強度可充分發揮。 研究結果得知，鋼管混凝土柱試體之側向強度與韌性並不因混凝土強度之不同而有顯著的差異。相同的鋼管寬厚比，縱向加勁板對強度與韌性之貢獻不如增加鋼板厚度有效。加勁處理可延緩鋼管局部挫屈的發生，進而增加鋼管混凝土柱之韌性能力。縱向加勁板可有效提升鋼管混凝土柱之結構性能，尤其在薄鋼板試體組中之提升幅度特別顯著。剪力釘與無加勁處理於強度及韌性表現上相距不遠，此顯示鋼材與混凝土間之握裹行為良好與否，並不顯著影響試體之彎矩強度與耐震行為。

An experimental research is conducted to study the strength and ductility of the concrete-filled steel welded tubular columns. Nine specimens were tested under constant compressive load and cyclic lateral loads to simulate the axial load as well as the seismic load. The parameters considered were strength of the concrete, width-thickness ratio, and type of stiffening (longitudinal stiffener or shear stud). Observations during the tests indicate that the local buckling of the steel plate occurred after yielding. The failure of specimens were reached when the weld between the column plates cracked. The study shows that different strengths of the concrete had a little effect on the structural behavior of the columns. Shear studs play an insignificant role on the flexxural strength and seismic performance. Moreover, longitudinal stiffeners not only can increase the strength and ductility of the columns but also can prevent the local buckling of the steel plate effectively, especially for the thin wall tubular columns.