预应力部分外包组合梁抗裂性能试验

为研究预应力部分外包组合梁的抗裂性能,设计制作了2组共8根试验梁,以预应力水平和截面宽高比为主要参数分析其对抗裂度和裂缝特征的影响。试验表明:施加预应力后2组组合梁的开裂荷载均值分别提高42%和23%,且延缓裂缝发展的作用显著,但达到较高预应力水平后,效果减弱。适当增大截面宽高比对提高预应力组合梁的开裂弯矩及阻裂性能有重要的作用,也能大幅提高极限承载力。结合已有理论和试验结果,提出开裂荷载的计算公式,与试验值比较,吻合度较高。

Crack Resistance Study of Prestressed Partial External Composite Beam

In order to study the crack resistance of prestressed composite beams, two groups of 8 test beams were designed and fabricated, and the influence of prestressing level and section aspect ratio on crack and crack characteristics was analyzed.The results show that the average cracking load of the two groups of composite beams increased by 42% and 23% respectively after prestressing, and the effect of delaying crack development was significant, but the effect weakened after the prestressing level was higher. It is important to increase the ratio of section width to section height to improve the cracking moment and crack resistance of prestressed composite beams, which can greatly increase the ultimate bearing capacity. Combined with the existing theory and test results, the calculation method of cracking load is proposed.