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钢筋混凝土桁架拱桥兼具桁架桥自重轻和拱桥结构受力合理的优点,曾一度在我国广泛应用,但随着时间推移,其中许多桥梁已面临加固的需求。以某钢筋混凝土斜杆桁架拱桥为例,分析了其典型的结构病害与不足,通过建立桁架拱桥有限元模型,计算不同杆件内力,分析了各类杆件的受力特征;针对杆件不同受力特征优化提出了针对性的加固措施。对受拉为主的内倾斜杆,在其内外两侧纵向粘贴CFRP布进行抗拉加固;对受压为主的外倾斜杆,在其表面环向粘贴CFRP布进行抗压增强;对受弯为主的上弦杆及跨中实腹段,在其截面受拉侧纵向粘贴CFRP布,提高截面抗弯承载能力;对截面薄弱、承受压力及一定弯矩的下弦杆,采用增大截面法进行加固,增大其截面承载力与截面刚度;同时,给出了横系梁、微弯板、铺装层的加固处理方法。
Reinforced concrete truss arch truss has the advantages of self-weight of light truss bridges and reasonable force of arch bridge structure. It was once widely used in our country, but many of them have been facing the need of reinforcement as time goes by. Taking a reinforced concrete diagonal truss arch bridge as an example, the typical structural defects and defects are analyzed. The internal force of different bars is calculated by establishing the finite element model of the truss arch bridge. The force characteristics of various types of bars are analyzed. Force characteristics optimization proposed targeted reinforcement measures. Tension-oriented internal oblique inclined rod, both sides of its internal and external longitudinal affixed to the CFRP cloth for tensile reinforcement; compression of the main external inclined rod, the surface of the ring CFRP cloth affixed to the ring to enhance the pressure; bending Based on the winding rod and the actual section of the mid-span, in its cross-section of the longitudinal side of the CFRP Cloth affixed to improve the section bearing capacity of bending; on the cross-section of weak, under pressure and a certain bending moment of the lower chord, using an enlarged section method Strengthen and increase its section bearing capacity and section stiffness; the same time, given transverse girder, micro-bending plate, pavement layer reinforcement method.