This article proposes a new kind of continuous composite beam that consists of steel box-girder and ultra-high-performance concrete waffle slab. The ultra-high-performance concrete helps increase the ultimate capacity and span of structure while reducing the risk of cracking that occurs with ordinary concrete. In order to investigate the mechanical properties of this new type of composite structure, two scaled specimens were designed and tested. One was a steel–ultra-high-performance concrete continuous composite beam, whereas the other, as a control specimen, was a prestressed steel-concrete continuous composite beam. The test results indicate that the bending capacity of steel–ultra-high-performance concrete continuous composite beam is 1.2 times that of steel-concrete continuous composite beam; the cracking strength of steel–ultra-high-performance concrete continuous composite beam is larger than 20 MPa, much higher than the conventional one; the crack development pattern of steel–ultra-high-performance concrete continuous composite beam has its own characteristics, and the cracks appeared in ultra-high-performance concrete slab dominated by micro-cracks with smaller length are numerous and intensive. A finite element model was developed to predict the behavior of steel–ultra-high-performance concrete continuous composite beam. Comparing the numerical and experimental results indicates that, generally, the numerical model can simulate the structural behavior of steel–ultra-high-performance concrete continuous composite beam reasonably. Based on the numerical model, a series of parameter analyses were performed, which indicate that the strength grade of steel, web, and bottom plate thickness play an important role in improving the bending capacity of steel–ultra-high-performance concrete continuous composite beam; the axial tensile strength of ultra-high-performance concrete, rib, and top plate height of ultra-high-performance concrete slab can enhance the bending capacity to a certain extent.

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钢-超高性能混凝土连续组合梁性能试验与数值研究

本文提出了一种由钢箱梁和超高性能混凝土华夫板组成的新型连续组合梁。超高性能混凝土有助于提高结构的极限承载力和跨度，同时降低普通混凝土发生开裂的风险。为了研究这种新型复合结构的力学性能，设计并测试了两个按比例缩放的试样。一个是钢-超高性能混凝土连续组合梁，而另一个作为控制试件，是预应力钢-混凝土连续组合梁。试验结果表明，钢-超高性能混凝土连续组合梁的抗弯能力是钢-混凝土连续组合梁的1.2倍；钢-超高性能混凝土连续组合梁的抗裂强度大于20 MPa，远高于常规梁；钢-超高性能混凝土连续组合梁的裂缝发展模式有其特点，超高性能混凝土板中出现的裂缝以长度较小的微裂缝为主，裂缝多而密集。开发了一个有限元模型来预测钢-超高性能混凝土连续组合梁的行为。数值与试验结果对比表明，一般情况下，该数值模型可以合理模拟钢-超高性能混凝土连续组合梁的结构行为。基于数值模型，进行了一系列参数分析，说明钢、腹板和底板厚度的强度等级对提高钢-超高性能混凝土连续组合梁的抗弯能力有重要作用；超高性能混凝土的轴向抗拉强度、肋、超高性能混凝土板的顶板高度可在一定程度上提高抗弯能力。