國內於2007年起，國家地震研究中心開始推行台灣新型高強度鋼筋混凝土結構系統研發計畫(Taiwan New RC)。本研究配合Taiwan New RC計畫，於本年度規劃四根高強度鋼筋混凝土矩形懸臂梁試體(a/d=3.0)，透過反覆加載試驗，探討不同箍筋型式(箍筋採用SD785竹節筋)對耐震行為影響。 塑鉸區箍筋型式對耐震行為影響，梁HRB-S1b為封閉箍筋由帽蓋繫筋(90°-135°橫向交錯排置) 與U型肋筋之組合，在DR=3.5%以前，試體強度與梁HRB-S1a (標準封閉箍筋)比較，並無明顯差異。但在DR=3.5%以後，梁HRB-S1b試體剪力強度有較早衰減之情形。 至於繫筋有交錯排置(梁HRB-S2a)與無交錯排置(梁HRB-S2b)比較，其結果與梁HRB-S1系列相反。即在DR=3.5%以前，HRB-S2b試體在試體強度上與HRB-S2a試體比較，則有較低之現象，但在DR=3.5%以後，兩試體剪力強度衰減情形較無明顯差異。 由試驗結果得知，各試體在DR=3.5%時，箍筋量測最大應力範圍從680MPa至895MPa(實際降伏應力)以上，且塑鉸區混凝土對剪力仍有貢獻。;Since 2007 in Taiwan, the National Center for Research on Earthquake Engineering (NCREE) has launched the Taiwan New RC Project. This study, belonged to one of topics in the project, was designed four rectangular cantilever beams with a/d=3.0 and different stirrup layouts. The objective of this study is to investigate the seismic behavior of these specimens. The shear strength of the beam HRB-S1b, which had shear stirrups with the combination of U-shape ties and lateral 90°-135° degree tie bars on the top of U-shape ties, did not show significantly different in comparison with the beam HRB-S1a, which had standard close-type stirrups, when the hysteresis loop sustained until DR(drift ratio)=3.5%. However, after DR=3.5%, the beam HRB-S1b had earlier shear degradation comparing with the beam HRB-S1a. The other two specimens (HRB-S2a and HRB-S2b) were the beam HRB-S2a, which had shear stirrups with 90°-135° degree hook vertically taking turn to tie the middle flexural bar, and the beam HRB-S2b, which had no take-turn 90°-135° hook arrangement in a substandard method. The beams HRB-S1 series had contrary results to the beams HRB-S2 series. That is, the beam HRB-S2b had lower shear strength than the beam HRB-S2a when the hysteresis loop reached DR=3.5%. However, they (HRB-S2a and HRB-S2b) had similar tendency in the shear strength degradation. Test results indicated that the measured maximum stress of stirrups of all the specimens ranges from 680MPa to more than 895MPa (the actual yielding stress). In the fore-mentioned specimens, concrete still had shear contribution in plastic hinge zone.
