集中荷载作用下腹板开孔混凝土简支箱梁抗弯性能研究

发布时间：2018-05-18 02:24

本文选题：双层交通 + 简支箱梁　；参考：《湖南科技大学》2014年硕士论文

【摘要】：混凝土箱梁因具良好受力性能而特别适用于中等跨度城市桥梁。通过取消箱梁横隔板，使顶、底板均成为桥面系，同时在腹板上开设必要的孔洞以满足通风、采光及消防等要求，可实现双层交通。该设计方法对解决城市交通拥挤问题具有重要现实意义。本文基于国家自然科学基金资助项目“面向双层交通混凝土箱形梁受力机理及设计方法研究”（项目批准号：51378202）展开相关研究。以1:6比例设计了腹板开孔混凝土箱梁，对其在双层集中荷载作用下抗弯受力性能进行系统试验研究和理论分析，得出的主要结论如下：（1）对双层集中荷载作用下腹板开孔混凝土简支箱梁在弹性范围内的抗弯受力性能进行了大比例模型试验研究，并就腹板开孔与否对其受力性能影响进行了有限元分析，研究成果可为混凝土箱梁双层桥相关设计提供参考。（2）对于底板边梁而言，荷载作用在顶板边梁（工况一）时底板边梁跨中挠度为0.29mm，荷载作用于底板边梁（工况三）时为0.32mm，较工况一而言增大10.3%；对于底板中梁而言，荷载作用在顶板中梁（工况二）时底板中梁3/8跨处产生的挠度是0.27mm，荷载作用于底板中梁（工况四）时为0.31mm，较工况二而言增大了14.8%，说明底板加载对腹板开孔简支箱梁的中梁挠度影响较大。（3）就腹板开孔与否对双层集中荷载作用简支箱梁抗弯受力性能的影响进行了有限元分析。分析结果表明：以底板边梁为例，工况一~工况四作用下，，不开孔梁的跨中挠度分别为0.26mm、0.22mm、0.08mm、0.04mm；开孔梁对应的挠度值分别为0.30mm、0.24mm、0.33mm、0.20mm，较不开孔箱梁而言，开孔箱梁跨中挠度分别增大了1.2倍、1.1倍、3倍和4倍。相对于不开孔梁而言，工况一和工况二（均为顶板加载）加载对开孔梁加载其跨中挠度增大1.15倍，工况三和工况四（均为底板加载）加载对开孔梁加载其跨中挠度增大3.5倍，底板加载对开孔梁的挠度有较大影响。（4）对于不开孔梁而言，工况一作用下1-1截面顶板和底板的剪力滞系数变化范围分别为0.71~1.32和0.82~1.25，2-2截面对应的数值分别为0.89~1.09和0.93~1.06；对于开孔梁而言，工况一作用下1-1截面顶板和底板的剪力滞系数变化范围分别为0.69~1.36和0.73~1.26，2-2截面对应的数值分别为0.56~1.46和0.89~1.07。开孔梁在各工况作用下截面剪力滞系数增大，最大增大量值达33.9%。因此，腹板开孔对承受双层荷载钢筋混凝土简支箱梁抗弯受力性能有较大影响。
[Abstract]:Concrete box girder is especially suitable for medium span city bridge because of its good mechanical performance. By canceling the transverse partition of the box girder, the top and bottom plates can become the bridge deck system, and at the same time opening the necessary holes in the web plate to meet the requirements of ventilation, lighting and fire protection, the double layer traffic can be realized. This design method has important practical significance to solve the problem of urban traffic congestion. This paper is based on the National Natural Science Foundation's project "study on the Force Mechanism and Design method of Double-Deck Traffic concrete Box Beams" (Project Grant No.: 513782022). The concrete box girder with web openings is designed at 1:6 scale. The bending behavior of the box girder subjected to double-layer concentrated load is systematically studied and analyzed theoretically. The main conclusions are as follows: In this paper, the flexural behavior of simply supported concrete box girder with web openings under the action of double layer concentrated load is studied in a large scale model test, and the finite element analysis is carried out on whether the web is perforated or not. The research results can provide reference for the related design of concrete box girder double-deck bridge. (2) for the side beam of the bottom slab, when the load acts on the side beam of the roof slab (working condition 1), the deflection of the center span of the side beam of the bottom slab is 0.29 mm, and the load acting on the side beam of the floor plate (working condition 3) is 0.32 mm, which is 10.3 mm larger than that of the working condition 1; for the middle beam of the bottom plate, The deflection of the 3 / 8 span of the beam in the bottom plate is 0.27 mm when the load is applied to the beam in the top plate (working condition 2) and 0.31 mm when the load acts on the beam in the bottom plate (working condition 4), which is 14. 8 mm larger than the second condition, which shows that the loading of the bottom plate can make a simple box with a web hole. The deflection of the middle beam has a great influence. 3) finite element analysis is carried out on the influence of web opening or not on the flexural behavior of simply supported box girder under double-layer concentrated load. The analysis results show that the mid-span deflection of the non-perforated beam is 0.26mm / 0.22mm / 0.08mm / 0.04mm, respectively, and the corresponding deflection of the open-hole beam is 0.30mm / 0.24mm / 0.33mm / 0.20mm respectively, which is more than that of the box girder without opening hole, taking the side beam of the bottom plate as an example, and under the action of one to four working conditions, the mid-span deflection of the non-perforated beam is 0.26mm / 0.22mm / 0.08mm / 0.04mm, respectively. The midspan deflection of open box girder is increased by 1.2 times, 1.1 times and 4 times, respectively. Compared with the non-perforated beam, the mid-span deflection of the open-hole beam is increased by 1.15 times under the loading of working conditions 1 and 2 (both roof loading), and 3.5 times by the loading of working conditions 3 and 4 (all of which are loaded by the bottom plate). The load of the bottom plate has great influence on the deflection of the beam. (4) for non-perforated beams, the shear lag coefficients of the top and bottom plates with 1-1 section under one working condition vary from 0.71 to 1.32 and from 0.82 to 1.25 / 2, respectively, and the corresponding values are 0.891.09 and 0.931.06, respectively, for open-hole beams. The variation range of shear lag coefficient of 1-1 cross-section roof and floor is 0.69 ~ 1.36 and 0.73 ~ (1.262-2) respectively. The corresponding values are 0.56 ~ 1.46 and 0.89 ~ 1.07, respectively. The shear lag coefficient of the cross-section increases and the maximum increase value reaches 33.9. Therefore, the web opening has great influence on the flexural behavior of reinforced concrete simply supported box girder under double deck load.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441;U448.217

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