鋼筋混凝土剪力牆連接梁耐震行為之研究

Abstract

近年鋼筋混凝土建築往高層建築發展已為趨勢，而連接式剪力牆系統則為常見的高樓建築核心抗側力系統。不像傳統型式的剪力牆系統，連接式剪力牆可以滿足空間使用上的需求。而連接式剪力牆的韌性必須建立在連接梁有良好的變形能力。過去的研究顯示出連接梁若要有良好的變形能力，則需提供足夠的剪力強度，在變形較大之時足夠之維持其剪力強度，則破壞型式會是較為安全的撓曲破壞。因此本研究主要經由實驗與分析方式，來探討改變材料性質與跨深比之下，剪力強度能否有效提升及維持。 本實驗設計了八座試體探討不同跨深比、材料強度(混凝土、對角鋼筋降伏)以及端部對角鋼筋偏折與否對連接梁之剪力強度影響。實驗結果顯示降低跨深比將使得連接梁撓曲剪力需求迅速抬高，須提供更高的對角鋼筋量，混凝土強度提高可有效提升剪力強度，但也加速軟化現象，使得位移能力下降。對角鋼筋降伏強度提高對於剪力強度及位移能力都能有所提升，另外對角鋼筋於端部偏折與否對於強度及位移行為無明顯差異。最後，本研究亦對剪力連接梁之剪力強度預測，建議有效的預測模型。

High-rise reinforced concrete buildings can be built with the aids of the structural wall. In these cases, ductile coupled shear wall, an efficient lateral-force-resisting system, is usually placed at the core the coupled wall system can area of tall building. As compared to the traditional shear wall system, satisfy better the demand of space. The ductility of coupled shear wall requiresa good deformation capability on connected beams. According to previous researches, adequate shear strength is indispensable for develop went of ductility. Therefore this research focuses on maintaining and improving shear strength by varying the properties of material and apect-ratio. Eight full-scale specimens were designed to study the effects of shear strength under different aspect-ratio, properties of material (concrete strength, steel strength of diagonal bar), and alignment at the end of diagonal bar. Test results indicate that reducing the aspect-ratio will increase the shear demand. Meanwhile, it indicates that the more amounts of diagonal reinforcements are required. Although using higher strength of concrete can increase the shear capacity, it accelerates the softening effect of concrete. Moreover, providing higher yielding strength of diagonal bar could improve limited shear capacity and deformation ability. The different detailing at the ends of diagonal bar made no different on strength development and deformation capacity. This research also proposed an analytical model to predict the shear strength of coupling beam.