摘要
为了研究活性粉末混凝土构件抗裂性能,制作了两根预应力吊车梁进行试验,得到吊车梁在各级荷载作用下裂缝开展图,通过分析梁受力至破坏整个过程,获得开裂弯矩,建立受拉区裂缝宽度与裂缝间距的计算公式。研究结果表明:①RPC梁在计算开裂弯矩时,应该考虑RPC和钢纤维的拉结作用,并在此基础上建立开裂弯矩计算公式;②钢纤维对裂缝宽度展开有阻滞作用,活性粉末混凝土的延性比普通混凝土更好,其裂缝宽度计算公式可以在无粘结预应力技术规程公式的基础上乘以一个相应的折减系数α=0.8;③考虑RPC抗拉强度贡献,裂缝间距可以按照普通混凝土计算,但须乘以一个α=0.75左右的修正系数。
In order to study the anti-cracking performance of the reactive powder concrete, two prestressed con- crete crane beams were tested, crack evolutions and patterns under different load levels were observed. Behav- iours up to the failure state of the beams were analyzed, and the cracking moment of each beam was obtained. Calculation formula of the crack width and the crack spacing were developed. The results show that ： （ 1 ） In cal- culation of cracking moment of the RPC beam, effects of RPC and steel fiber binding should be considered. The corresponding cracking bending moment calculation formula were establish; （2） steel fiber has positive effect to reduce the crack width; and the reactive powder concrete has better ductility than the ordinary concrete. The calculated crack width of the RPC beams is equal to the crack width calculated by following the formula for the unbonded prestressed beams multiplied by a reduction coefficient α= 0. 8; （3） considering the contribution of RPC tensile strength, the crack spacing can be calculated according the formula for the ordinary concrete beams and then the value should be multiplied by a correction coefficient α =0. 75 to get the final result.
出处
《结构工程师》
北大核心
2013年第2期15-21,共7页
Structural Engineers
基金
广西岩土力学与工程重点实验室资助课题(11-cx-04)
科技攻关项目(桂科攻0995004)
