Abstract

In this paper, an empirical model for a strut efficiency factor $\left({\mathrm{\beta }}_{\mathrm{s}}\right)$ is proposed and introduced in to the softened strut and tie model to predict the ultimate shear strength and the corresponding ultimate load of simply supported steel reinforced concrete (RC) deep beams under 4-point bending without transverse reinforcements. The proposed model accounts for the influence of shear span to depth ratio $\left(\mathrm{a}/\mathrm{d}\right),$ concrete compressive strength$\mathrm{}({\mathrm{f}}_{\mathrm{c}}^{\mathrm{\text{'}}}),$ area of steel reinforcement $\left({\mathrm{A}}_{\mathrm{s}}\right),$ diagonal strut angle$\mathrm{}\left(\mathrm{\theta }\right)$ and width of loading plate$\mathrm{}\left({\mathrm{l}}_{\mathrm{t}}\right).$ In addition, an empirical model for a stiffness degradation coefficient $\left({\mathrm{k}}_{\mathrm{f}}\right)$ accounting for the influence of overall depth of the beam$\mathrm{}\left(\mathrm{D}\right)$ and the diagonal strut angle $\left(\mathrm{\theta }\right)$ is proposed and introduced in to a deflection prediction model to predict the corresponding ultimate deflection. In this study, 12 numbers of steel RC deep beams are cast and tested. The empirical models are proposed for the strength and the deflection prediction using regression analysis based on the test results of 373 and 86 steel RC deep beams respectively, which includes the 12 test beams of the present study. The proposed models are validated by accounting for the maximum range of the parameters involved in the database. The predictions based on the proposed models are compared with the predictions based on the other models. The comparison shows that the proposed models can accurately predict the ultimate load and the mid span deflection of the steel RC deep beams.

摘要

在本文中，一个支撑效率因子的经验模型$\left({\mathrm{\beta }}_{\mathrm{s}}\right)$提出并引入软化支柱和系杆模型，以预测无横向钢筋的 4 点弯曲简支钢筋混凝土 (RC) 深梁的极限抗剪强度和相应的极限载荷。所提出的模型考虑了剪跨深度比的影响$\left(\mathrm{一个}/\mathrm{d}\right),$混凝土抗压强度$\mathrm{}({\mathrm{F}}_{\mathrm{C}}^{\mathrm{\text{'}}}),$钢筋面积$\left({\mathrm{一个}}_{\mathrm{s}}\right),$对角撑杆角度$\mathrm{}\left(\mathrm{\theta }\right)$和装载板的宽度$\mathrm{}\left({\mathrm{l}}_{\mathrm{吨}}\right).$此外，刚度退化系数的经验模型$\left({\mathrm{ķ}}_{\mathrm{F}}\right)$考虑梁总深度的影响$\mathrm{}\left(\mathrm{D}\right)$和对角支柱角度$\left(\mathrm{\theta }\right)$提出并引入挠度预测模型以预测相应的最终挠度。在这项研究中，铸造并测试了 12 根钢筋混凝土深梁。分别基于373和86钢RC深梁的试验结果，包括本研究的12根试验梁，提出了强度和挠度预测的经验模型。通过考虑数据库中涉及的参数的最大范围来验证所提出的模型。将基于所提出模型的预测与基于其他模型的预测进行比较。对比表明，所提出的模型可以准确预测钢筋混凝土深梁的极限荷载和跨中挠度。