近年來，國家地震工程研究中心推行台灣新型高強度鋼筋混凝土結構系統研發計畫(簡稱Taiwan New RC計畫)。本研究配合Taiwan New RC計畫，設計三組高強度矩形懸臂梁試體(a/d=3.0)，透過反覆加載試驗，探討不同剪力筋間距下 (s= d, d/2, d/4) ，試體耐震行為的差異，並討論相同配置之三組普通強度試體之間的差異。 由試驗結果得知，以ITG-4.3R計算New RC試體的標稱撓曲強度，會比傳統ACI 318方法較具準確性。而標稱剪力強度評估方面，高強度與普通強度試體均較為保守。由於ACI 318耐震設計篇，假設梁塑鉸區混凝土剪力貢獻為零，以及斜裂縫角為45°的假設較實際量測為大所致。 比較箍筋間距均為d/4之高強度與普通強度試體的破壞模式，在DR=4%時，兩者(高強度與普通強度試體)均為撓曲破壞行為。但在最終DR=7%時，普通強度試體(d/4)在距離固定端d/2之梁腹處，有混凝土壓桿壓碎的現象。高強度試體之初始勁度與普通強度試體相當，但在韌性行為以及抗剪表現方面，則是以高強度試體為佳。 ;In recent years, the National Center for Research on Earthquake Engineering (NCREE) has launched the Taiwan New RC Project. This study belonged to one of topics New RC project. This study designed six rectangular cantilever beams (three New RC and three Normal RC) with a/d=3.0 and different hoop spacings (s= d, d/2, d/4). The objective of this study is to investigate the seismic behavior of these specimens. Test results indicated that predicted flexural strength using ITG-4.3R method was suitable for New RC beams. However, the nominal shear strength was conservative because the seismic specification in ACI 318 assumed that Vc is zero in the plastic hinge zone and the inclination of diagonal crack is 45°, which is larger than measured values.This study also discussed the differences in seismic behavior between New RC and Normal RC specimens. At DR(drift ratio)=4%, the concrete compression crushing of what we called flexural failure was occurred at beam fixed and for both New RC and Normal RC beams. However, at the end of test DR=7%, the failure mode for Normal RC beam with hoop spacing d/4 turned to diagonal concrete struct compression failure occurred in the web d/2 away from the beam fixed end, This failure mode of the Normal RC beam at the end of test is slightly diffenent from the New RC beam. The initial stiffness of New RC beams is similar to that of Normal RC beams. Nevertheless, the performance of New RC beams in flexural ductility and shear resistance is better than Normal RC beams.
