结合梁自锚式悬索桥主缆锚固区传力机理研究

发布时间：2019-03-13 17:13

【摘要】：自锚式悬索桥近年来发展很快,桥型也日益多样化,过去建造的自锚式悬索桥主梁大多采用钢结构或混凝土结构,现在钢—砼结合梁作为一种新的桥梁结构形式已经被运用于自锚式悬索桥中。钢—砼结合梁独特的受力性能与结合梁自锚式悬索桥建设的不断增加,使得对其主缆力在锚固区内的传递机理研究愈加受到重视。本文结合银川滨河黄河大桥,对结合梁自锚式悬索桥进行了研究,具体研究内容与取得成果如下:(1)基于实桥对主梁各位置应力应变进行测试,分析主梁内力分布规律,根据实际结构分别建立了全桥杆系有限元模型和主缆锚固区局部精细有限元模型,根据以往研究成果对主梁不同材料的连接进行模拟,并将计算结果与测试进行对比,验证了计算模型的正确性;(2)根据有限元分析结果,对主缆锚固区的应力分布规律、剪力钉滑移情况和各构件轴力分担比例进行了分析,得出了主缆力在锚固区内的传递路径;在此基础上分析了主梁在多倍荷载下的受力性能,对主缆锚固区的承载能力极限状态进行探究,得出了锚固区极限状态下的破坏形式;(3)基于对主缆力传力途径及承载力极限状态的分析,提出不同参数的主缆锚固区设计方案,比较不同设计参数对锚固力传递机理与锚固区受力性能的影响,对结合梁自锚式悬索桥主缆锚固区的设计方法进行了探讨。分析结果表明:主梁在承受主缆锚固力后发生纵向压缩与面外弯曲,锚碇通过与主梁锚固加强部腹板的焊缝将主缆纵向力传递至腹板与顶板;顶板上的轴力以45°角向内扩散,一部分由纵梁腹板上方剪力钉传递到混凝土桥面板中,剩余部分通过剪力传递至纵梁腹板;在横梁作用下轴力由两侧扩散至中间,截面形成均匀整体受力,距梁端线20米处传力过程结束。在极限荷载下混凝土桥面板在端横梁上方发生拉裂,纵梁斜腹板与外腹板合拢的位置发生压裂,导致内部剪力钉失效发生破坏。降低端横梁宽度并加密普通横梁可以优化主缆力传递,横梁上剪力钉作用较小,可以采用集束布置以便施工。
[Abstract]:The self-anchored suspension bridge has developed rapidly in recent years, and the bridge type is also becoming more and more diversified. The self-anchored suspension bridge with self-anchored suspension bridge has been constructed by steel structure or concrete structure, and now the steel-anchored suspension bridge has been used as a new bridge structure in the self-anchored suspension bridge. The unique mechanical performance of the combined beam and the continuous increase of the self-anchored suspension bridge of the combined beam are more and more important to the study of the transmission mechanism of the main cable force in the anchorage zone. Combined with Yinchuan Binhe River Bridge, this paper studies the self-anchored suspension bridge of the combined beam, and the concrete research contents and achievements are as follows: (1) The stress and strain of the main beam are tested based on the real bridge, and the distribution law of the internal force of the main beam is analyzed. According to the actual structure, the finite element model of the full-bridge rod system and the local fine finite element model of the main cable anchorage zone are respectively established, and the connection of different materials of the main beam is simulated according to the previous research results, and the calculation result is compared with the test, and the correctness of the calculation model is verified; and (2) according to the finite element analysis result, the stress distribution law of the anchor zone of the main cable, the sliding condition of the shear nail and the proportion of the axial force of each component are analyzed, the transmission path of the main cable force in the anchoring region is obtained, the stress performance of the main beam under the multiple loads is analyzed, The limit state of the bearing capacity of the main cable anchorage zone is explored, and the damage form in the limit state of the anchorage zone is obtained; and (3) the design scheme of the main cable anchorage zone with different parameters is proposed based on the analysis of the force transmission route of the main cable and the limit state of the bearing capacity, The influence of different design parameters on the anchorage force transmission mechanism and the stress performance of the anchorage zone is compared, and the design method of the main cable anchorage zone of the combined beam self-anchored suspension bridge is discussed. The analysis results show that after the main beam is subjected to the anchoring force of the main cable, the longitudinal compression and the external bending of the surface of the main beam are caused, the longitudinal force of the main cable is transmitted to the web and the top plate by the weld of the web of the reinforced part of the main beam, and the axial force on the top plate is spread inward at an angle of 45 degrees, A part is transmitted to the concrete bridge deck by a shear nail above the longitudinal beam web, and the rest part is transmitted to the longitudinal beam web through the shearing force; the axial force is spread to the middle by the two sides under the action of the cross beam, the section forms a uniform whole force, and the force transfer process at the distance of 20 meters from the end of the beam is finished. Under the limit load, the concrete bridge deck is cracked at the upper part of the end cross beam, and the position where the oblique web of the longitudinal beam and the outer web are closed is broken, leading to the failure of the internal shear nail. The width of the end cross beam is reduced and the common cross beam can be used for optimizing the transmission of the main cable force, the action of the shear nail on the cross beam is small, and a cluster arrangement can be adopted for construction.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U448.25

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