进行了7个缩尺的小剪跨比钢筋混凝土独柱双支承桥墩模型试验研究。分析探讨了现有中国规范在计算钢筋混凝土独柱墩结构受弯裂缝宽度问题的适用性,给出了用于受弯裂缝宽度计算的修正钢筋名义拉应力计算公式。结合试验数据及回归分析结果,考虑混凝土抗剪强度、钢筋销栓作用、裂缝间骨料咬合作用、弯起钢筋及箍筋的竖向力分力等对抗剪的贡献,推导了剪切斜裂缝的裂缝宽度计算公式。计算结果表明:采用修正钢筋名义拉应力的独柱墩受弯裂缝计算公式的预测值与试验数据基本吻合,提出的斜裂缝宽度计算公式的预测值与参与对比的试验结果也十分接近,证实了该方法的合理性。
The experimental research of seven small scaled RC single column pier models with small shear-span ratio was carried out.The comparison and discussion of applicabilities of different codes in calculating bending crack width of RC single column pier were presented.A modified formula for bending crack width calculation was developed by revising the nominal tensile stress computational formula.Considering the contribution of concrete shear strength,reinforce dowel action,aggregate biting force,and vertical components of the tensile force of bending-up steel bar and stirrup,to the shear,the calculation formula for shear crack width was derived by the results of experimental study and regression analysis.The results show that the values predicted by the modified formula are in good agreement with the experiment test results of bending crack width in the RC single column pier and the results gained by the proposed calculation method for shear crack width are very close to the measured values of the experiment.The rationality of the proposed method in this paper is verified.