| 轻型组合桥面弧形缺口应力特征分析及现场试验 |
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| 引用本文： | 李立峰,曾研,裴必达,王连华.轻型组合桥面弧形缺口应力特征分析及现场试验[J].中国公路学报,2019,32(8):66-78. |
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| 作者姓名： | 李立峰 曾研 裴必达 王连华 |
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| 作者单位： | 湖南大学 土木工程学院, 湖南 长沙 410082 |
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| 基金项目： | 国家自然科学基金项目（51278183）；湖南省住房和城乡建设厅2015年度科学技术项目（KY201508） |
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| 摘 要： | 为深入研究钢-UHPC （Ultra-high Performance Concrete）轻型桥面组合体系对弧形缺口的应力改善程度，结合一座大跨自锚式悬索桥，针对正交异性钢桥面板（Orthotropic Steel Deck，OSD）结构铺设UHPC层前、后2种情形，选择3种不同弧形缺口形式，分别建立空间实体有限元分析模型，并采用简化加载、响应面加载2种方式进行分析，由此获得了弧形缺口应力、变形分布规律与车辆轴载位置之间的关系，揭示了弧形缺口出现峰值拉、压应力的原因。以此为基础，采用三轴加载车分别在铺设UHPC层前、后进行现场跑车试验，采集了弧形缺口多个关注点在不同横向加载位置的应力响应曲线，获得了各点的应力极值，并与有限元结果进行了对比分析。研究结果表明：铺设UHPC前、后弧形缺口关注点应力特征随荷载分布规律基本相同，面内应力为主、面外应力较小，拉应力主要由荷载偏载产生、加载区域长，而压应力主要由荷载直接作用于弧形缺口顶部产生，且加载区域短；采用传统简化加载方式难以获得弧形缺口处准确的拉应力峰值，并可能导致应力幅偏小，并由此提出了合理的加载方式；本桥五段线弧形缺口形式受力相对较好；铺设UHPC层能有效减少弧形缺口应力峰值，并在一定程度上缓解疲劳问题，是OSD结构提高疲劳性能的一种有效方案。
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| 关 键 词： | 桥梁工程 疲劳应力 有限元分析 轻型组合桥面 现场试验 |
| 收稿时间： | 2018-09-19 |
Stress Characteristic Analysis and Field Test on the Cutouts of Light-weight Composite Deck |
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| LI Li-feng,ZENG Yan,PEI Bi-da,WANG Lian-hua.Stress Characteristic Analysis and Field Test on the Cutouts of Light-weight Composite Deck[J].China Journal of Highway and Transport,2019,32(8):66-78. |
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| Authors: | LI Li-feng ZENG Yan PEI Bi-da WANG Lian-hua |
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| Affiliation: | School of Civil Engineering, Hunan University, Changsha 410082, Hunan, China |
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| Abstract: | The purpose of this research is to study the improvements in the stress state of a cutout after laying an ultra-high performance concrete (UHPC) layer on a steel-UHPC light-weight composite deck. A large-span self-anchored suspension bridge was chosen, and finite element models of an orthotropic steel deck (OSD) were built with/without a UHPC layer, including three types of the cutout. The traditional simplified loading method, and the response surface loading method were used in the finite element analysis to obtain the relationship between stress/displacement distributions and vehicle axle loading positions. Then, the cause of peak tension stress and peak compressive stress on the cutout was revealed by analyzing the deformation characteristics of the cutout. A field test was carried out using a loading vehicle in which the stress responses of the cutout at different lateral loading positions were measured for the OSD with/without the UHPC layer. Based on the experimental data, the measured results show that it follows a similar law as the calculated results; and the maximum stresses of the cutout were found. The numerical calculation results were also compared with the field measurement results. This research shows that the regularities of the stress distribution of the cutout are basically the same for the OSD with/without the UHPC layer, and the in-plane stress is dominant relative to the out-of-plane stress. A large portion of the transverse influence line of the cutout is in tension, and a small portion is in compression. The compressive stress is caused mainly by the load right above the cutout, whereas the tensile stress is mainly generated by the load that deviates from the position of the cutout. However, it is difficult to obtain the accurate peak tensile stress of the cutout using the traditional simplified loading method, and it may produce a smaller stress range. Therefore, the response surface loading method is recommended for fatigue design of the steel-UHPC light-weight composite bridge. Furthermore, our research shows that the fatigue performance of the cutout, which was used in a self-anchored bridge is the best among these cutout forms. The peak stress of the cutout was lowered effectively, and the fatigue performance improved significantly after laying the UHPC layer. Hence, the UHPC layer solution can be used as an effective scheme for improving the fatigue performance of the OSD. |
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| Keywords: | bridge engineering fatigue stress finite element analysis light-weight composite bridge deck field test |
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