连续刚构桥箱梁腹板裂缝成因分析及预应力效应研究

发布时间：2018-02-15 08:13

本文关键词： 连续刚构桥竖向预应力腹板裂缝　出处：《长安大学》2014年硕士论文　论文类型：学位论文

【摘要】：连续刚构体系桥梁以其跨越能力大，受力合理，整体性好的优点，在桥梁界得到快速发展。然而在桥梁的建设和运营过程中，箱梁腹板均在不同程度上出现了各种形式的裂缝。这些裂缝的出现不仅影响了桥梁的整体性和耐久性，而且还对结构的安全性造成了严重危害。本文主要通过研究竖向预应力和纵向预应力钢束对箱梁腹板产生裂缝的影响机理，分析各种状况下的腹板的受力状态，并提出相应的防止腹板裂缝的设计措施。本文主要研究以下几方面的内容：首先，，本文总结并归纳了箱梁腹板裂缝的主要形式和开裂部位，并具体分析了裂缝发生的原因、影响因素以及其受力机理；其次，依托工程实例建模，具体分析了不同状态下竖向预应力对箱梁腹板空间受力的影响，主要包括竖向预应力的损失、竖向应力筋的间距，竖向预应力筋的偏置和布置形式等方面，并提出了相应预防裂缝产生的设计措施；最后，针对现在纵向预应力钢束的不同布置形式，探讨了纵向钢束对箱梁腹板受力的影响，得出应该设置相应的纵向钢筋下弯束来协同腹板抗剪，防止裂缝产生。总之，在预应力混凝土连续刚构箱梁的设计中，在箱梁截面尺寸满足受力要求的情况下，合理的布置竖向预应力筋，可以有效的控制箱梁腹板的主拉应力和和剪应力不超出混凝土的强度极限值，从而防止裂缝开裂。同时，还应该设置相应的下弯束，保证腹板均匀受力，协同竖向预应力钢筋共同抗剪。
[Abstract]:The continuous rigid frame bridge has the advantages of large spanning capacity , reasonable stress , good integrity and rapid development in the bridge . However , in the construction and operation of the bridge , the web of the box girder has various forms of cracks in different degrees . The appearance of these cracks not only affects the integrity and durability of the bridge , but also poses a serious hazard to the safety of the structure . This paper mainly studies the influence mechanism of vertical prestress and longitudinal prestressed steel beam on the cracks in the web of box girder , analyzes the stress state of the web under various conditions , and puts forward the corresponding design measures to prevent the crack of web . Firstly , this paper summarizes and sums up the main forms and cracking parts of the cracks in the web of box girder , and analyzes the causes , influencing factors and the force mechanism of cracks . Secondly , based on the engineering case modeling , the influence of vertical prestress on the stress of the web of box girder is analyzed . Finally , according to the different layout of longitudinal prestressed steel beam , the influence of longitudinal steel beam on the stress of the web of box girder is discussed . In summary , in the design of prestressed concrete continuous rigid box girder , the vertical prestressed rib is reasonably arranged under the condition that the cross - sectional dimension of the box girder meets the stress requirement , so that the main tensile stress and the shearing stress of the web of the box girder can be effectively controlled not to exceed the strength limit value of the concrete , so that the crack is prevented .

【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441;U448.213

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