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为控制通车条件下预制小箱梁拼接施工过程中拼宽湿接缝两侧挠度差,防止混凝土早期开裂,介绍小箱梁桥拼接技术的两种优化施工方案。为分析老桥保持快车道通车对湿接缝两侧变形差的影响,建立小箱梁桥有限元模型,通过计算老桥通车条件下最不利荷载效应,重点对设置夹具以控制湿接缝两侧挠度差的小箱梁数值模型进行了深入研究,并对不设置夹具、跨中设置3道夹具和满跨布置夹具的有限元计算结果进行了比较。研究结果表明:对于通车条件下的预制小箱梁桥,在新旧小箱梁之间设置施工夹具控制两侧挠度差效果有限,若不设置施工夹具,湿接缝两侧最大挠度差仅为2.32mm,属于微幅振动范畴。研究成果为同类型小箱梁桥拼宽施工提供技术指导。
In order to control the difference of deflection on the both sides of the wide-width wet-jointed seam during the splicing of the prefabricated box-girder and to prevent the early cracking of the concrete, two kinds of optimal construction schemes for the splicing of the small box girder bridge are introduced. In order to analyze the influence of the old bridge on the deformation difference of the wet seams on the opening of the fast lane, a finite element model of the box girder bridge was established. By calculating the most unfavorable load effect of the old bridge on the road, The side box deflection of the small box girder numerical model conducted an in-depth study, and do not set the fixture, set the bridge across the 3 fixture and span the results of the layout of the fixture were compared. The results show that for the prefabricated box-girder bridge with open traffic conditions, there is a limited effect on the difference between the two sides of the existing small box girder to control the deflection of the two sides. If no construction fixture is provided, the maximum deflection difference between the two sides of the wet joint is only 2.32 mm, belonging to the micro-vibration category. The research results provide technical guidance for the same type of small girder bridge span construction.