预应力RPC-NC结合梁裂缝试验研究

发布时间：2018-06-06 07:08

本文选题：结合梁 + 活性粉末混凝土　；参考：《桥梁建设》2017年01期

【摘要】：为研究预应力活性粉末混凝土(RPC)-普通混凝土(NC)结合梁的开裂性能,以铁路32m的T形梁为原型,制作10根RPC-NC结合梁和1根纯NC梁进行抗弯试验。对比分析试验梁的裂缝分布形态、裂缝间距及短期裂缝最大宽度,并在铁路规范的基础上推求适合于预应力RPC-NC结合梁裂缝宽度的计算公式。结果表明:预应力度增大,RPC-NC结合梁裂缝分布的范围减小;RPC-NC结合梁的裂缝间距明显小于NC梁,RPC加入后裂缝更加密集,并伴随产生大量细小裂缝;RPC高度对于RPC-NC结合梁裂缝出现及稳定发展阶段影响很小,进入失稳扩展阶段后随着RPC高度的增加,RPC-NC结合梁裂缝宽度增长速率降低;纯NC梁裂缝进入稳定扩展阶段后的扩展速率和裂缝最大宽度都明显高于RPC-NC结合梁;在铁路规范中引入结合梁裂缝修正系数后,能合理计算RPC-NC结合梁短期裂缝宽度。
[Abstract]:In order to study the cracking behavior of prestressed reactive powder concrete (RPC-RPC-ordinary concrete) composite beams, 10 RPC-NC beams and 1 pure NC beam were fabricated with 32m T-shaped beams as the prototype for flexural tests. The distribution of cracks, the distance between cracks and the maximum width of short term cracks of the test beams are compared and analyzed. Based on the railway code, the formula for calculating the crack width of prestressed RPC-NC composite beams is derived. The results show that the range of crack distribution in RPC-NC composite beams with increased degree of prestress is smaller than that of RC beams, and the crack spacing of RPC-NC beams is more dense than that of RC beams. With a large number of small cracks produced, RPC height has little effect on the crack appearance and stable development stage of RPC-NC bonding beam, but the growth rate of crack width of RPC-NC composite beam decreases with the increase of RPC height. The crack propagation rate and the maximum crack width of the pure NC beam are obviously higher than that of the RPC-NC composite beam after entering the stable extension stage, and the short term crack width of the RPC-NC composite beam can be reasonably calculated by introducing the crack correction coefficient of the composite beam in the railway code.
【作者单位】：北京交通大学土木建筑工程学院;
【基金】：国家自然科学基金项目(51278040) 教育部中央高校基本科研业务费项目(2014YJS106)~~
【分类号】：U446.1

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