摘 要 輕質骨材在結構物上之應用日益廣泛，且其抗彎之能力亦已獲得證實，本研究之重點著重於輕質骨材鋼骨鋼筋混凝土構件承受多維載重時之撓曲扭轉行為，並探討其承受彎矩和扭矩聯合作用，以評估構件之反應。 本文針對輕質骨材鋼骨鋼筋混凝土構件承受純扭矩單向載重，及不同偏心距之反覆載重時之行為，進行一系列的實驗研究，由骨材單位重、鋼骨比、偏心距大小對構件之撓曲扭轉行為、扭轉勁度及韌性行為等之影響進行比較。研究結果顯示輕質骨材構件之開裂扭矩實驗值較理論值高出甚多，其比值亦較常重混凝土大，故輕質混凝土構件開裂前之強度略優於常重混凝土構件，而構件開裂後之勁度亦以輕質混凝土構件較佳，惟到達極限強度後，由於骨材破裂，導致輕質混凝土構件之衰減速度較常重混凝土構件為快。 ABSTRACT Application of light weight aggregate concrete to construction has become more popular during recent decades. Such designs are considered to be more economical and competitive compared with traditional concrete structures, because the composite members with less unit weight behave better when they are subjected to earthquake. This study is focused on the evaluation of seismic performance of steel reinforced concrete beams using light weight aggregate concrete. A series of combined bending and torsional loading tests were conducted to obtain the members’ flexural-torsional responses. Interaction equation for member strength calculation was proposed for engineering practices. It is also observed in this study that the effect of torsion on the flexural strength reduction is more significant than that in normal weight steel reinforced concrete members.