削邊對鋼筋混凝土托架剪力強度之影響

Effect of Dapped Edges on Shear Strength of Reinforced Concrete Corbels

本研究對26 個剪力跨度與有效深度比大於1 之削邊與未削邊鋼筋混凝土托架進行試驗。試驗結果顯示，含垂直箍筋之未削邊托架，其剪力強度高於含垂直箍筋削邊托架之剪力強度。試驗結果亦顯示，剪力跨度與有效深度比愈小之托架，其剪力強度愈高。混凝土抗壓強度愈高及垂直箍筋參數愈高之托架，其剪力強度也愈高。本文亦建議了一個托架剪力強度之分析方法。經由試驗結果與分析值之比較得知，以本文所建議之分析方法預測托架之剪力強度，其預測精度優於ACI 規範之壓拉桿模型。

In this study, 26 reinforced concrete corbels with shear span-to-depth ratio greater than unity were tested to study the effect of dapped edges on shear strength of reinforced concrete corbels. Test results indicate that the shear strength of corbels without dapped edges is higher than that of corbels with dapped edges. Test results also indicate that the lower the shear span-to-depth ratio, the higher the shear strength of corbels is. The higher the compressive strength of concrete, the higher the shear strength of corbels is. The higher the vertical stirrup parameter, the higher the shear strength of corbels is. An analytical model for determining the shear strength of reinforced concrete corbels is also proposed in this paper. Both the shear strengths predicted by the proposed model and the strut-and-tie model of ACI Code are compared with test results. The comparison shows that the proposed model can more accurately predict the shear strength of reinforced concrete corbels than the strut-and-tie model of ACI Code.