UHPC矮肋桥面板抗弯性能研究

为研究UHPC矮肋桥面板的抗弯性能并验证其在多跨大跨连续梁中的适用性，以滨州黄河大桥为背景，提出两种UHPC矮肋板方案（平均板厚分别为16.4 cm和14.3 cm）.首先建立实桥有限元模型，得到实际荷载作用下桥面板UHPC应力和栓钉剪力.接着，进行足尺抗弯试验，获得矮肋板从加载至破坏的过程中裂缝萌生与发展特征、荷载-位移曲线和应变分布规律等.试验表明，底部钢板的设置可以有效限制UHPC裂缝的发展，在钢板屈服前裂缝宽度呈线性发展；两种方案开裂应力分别为16.8 MPa和15.6 MPa，经过实桥有限元计算得到两种桥面板方案的纵向受力安全系数分别为2.2和1.5；钢板屈服后主裂缝迅速出现，最终桥面板纵肋受拉裂缝快速发展，顶面出现受压裂缝，认为试件破坏；然后，考虑UHPC材料受拉贡献，结合UHPC规范对结构抗弯承载能力进行验算，结果表明，当采用截面非线性方法并使用材料实际性能参数时，可以预测UHPC矮肋板的极限弯矩，计算值和试验值的比值分别为0.95和1.01.最终，对结构关键设计参数进行分析，结果表明，UHPC抗拉强度对极限弯矩的影响较小，增加钢板厚度是提高其极限弯矩的有效途径，窄而高的纵向加劲肋具有更高的受力效率.

Research on Flexural Performance of UHPC Lowly Ribbed Deck Panel

In order to study the flexural performance of ultra-high performance concrete (UHPC) lowly ribbed deck panel and verify its feasibility in multi and long-span continuous beams, two different schemes of UHPC lowly ribbed deck panel were proposed based on the Bin Zhou Yellow River Bridge (average thickness: 16.4 cm and 14.3 cm). Firstly, the practical finite element model was established to obtain the stress of UHPC and the shearing force of headed studs. Secondly, two large-scale bending tests were carried out to obtain the crack initiation and development characteristics, the load-displacement curve, and the strain distribution law. The test shows that the bottom steel plate can resist the development of the crack. The crack width increases linearly with the load. The cracking stress of the two schemes is 16.8 MPa and 15.6 MPa, respectively, with a safety factor of 2.2 and 1.5. When the steel plate yielded, the main crack appeared rapidly, and specimens failed because the tensile crack developed rapidly and the compressive crack appeared. Then, after considering the contribution of UHPC tensile strength, the ultimate bending capacity was calculated by combing the UHPC specifications. The calculation result shows that when the factual material properties are considered, the ultimate capacity can be predicted well through the section nonlinear method. The ratios between the predicted result and experimental result are 0.95 and 1.01 respectively. Finally, the critical design parameters were analyzed. The result indicates that the influence of UHPC tensile strength is small. Increasing the thickness of the steel plate can be an effective way to improve the ultimate bending capacity. The narrow and high rib has higher force efficiency.