自充填混凝土梁在高強度箍筋使用下之剪力強度測試與探討

Abstract

本研究主要在探討使用高拉力剪力筋之自充填混凝土及傳統混凝土梁受靜態載重作用下之剪力行為。試體共製作19支梁試體，其中15支為自充填混凝土梁，另4支為傳統混凝土梁。探討之變數包括混凝土的種類、混凝土強度、剪力箍筋量、剪跨比等，期望對自充填混凝土及傳統混凝土梁使用高拉力剪力筋後之剪力強度與延展性有所了解。試驗結果可歸納如下： 1、自充填混凝土及一般普通混凝土RC梁進行剪力試驗，發現兩系列梁的 裂縫發展與破壞過程相當近似。 2、自充填混凝土傾斜破裂剪力Vcr和極限剪力強度Vu，平均值為ACI計算值的1.16及1.08倍，所以ACI分析尚可適用於自充填混凝土梁在高強度箍筋（Ulbon）使用下的分析。 3、Ulbon剪力筋強度高且延展性佳，因此在梁破壞瞬間Ulbon不會突然斷裂，使得載重能力不致於突然的降低。 4、ACI規範限制剪力鋼筋設計降伏強度不得大於60ksi之規定應可適度放寬。 5、試驗結果發現，在具有相同混凝土強度、縱向鋼筋比、剪力箍筋比、剪跨深比的自充填混凝土梁與一般傳統混凝土梁，以自充填混凝土梁之極限剪力強度較高且韌性的表現較佳。 關鍵字：自充填混凝土、高拉力箍筋、梁、剪力、韌性

The purpose of this study is to investigate the shear behavior of self compacting concrete（SCC）and ordinary property cement（OPC）beams with high tensile steel ULBON under static load﹒A total of nineteen beams specimens were made in this study﹐fifteen were SCC beams and the rest were OPC ones﹒The parameters included two kinds of concrete﹐concrete strength﹐amount of shear reinforcement and shear span-to-depth ratio﹒Wishing to comprehend shear strength and ductility after using high tensile steel ULBON as shear reinforcement in SCC and OPC beams﹒The following conclusions can be made from the test results﹒ 1、The pattern of crack initiation and propagation for OPC and SCC beams are similar to each other﹒ 2、Cracking loads Vcr and ultimate strength Vu for SCC beams are 1.16 and 1.08 of the values calculated by ACI﹐which demonstrated the suitability of ACI equations for high strength stirrups﹒ 3、The reason that load capacity of beam does not drop significantly after peak is because of the high strength and ductility of Ulbon﹒ 4、The current ACI code requires that fy≦60 ksi could be suitable increase﹒ 5、At the same parameters﹐the results show the self compacting concrete beams have greater ultimate shear strength and ductility over than ordinary property cement ones﹒ Keyword：self compacting concrete、SCC、beam、high tensile steel、shear strength、ductility