【摘要】：自錨式懸索橋的主纜錨固于主梁兩端,對(duì)主梁施加巨大的水平分力,如果支撐主梁的吊索發(fā)生斷裂,可能導(dǎo)致主梁破壞,進(jìn)而導(dǎo)致橋梁整體垮塌。隨著使用時(shí)間的增長(zhǎng),吊索因腐蝕而承載力降低,可能發(fā)生突然斷裂,使結(jié)構(gòu)發(fā)生劇烈振動(dòng),導(dǎo)致結(jié)構(gòu)內(nèi)力變化較大,甚至危及橋梁安全。本文以一座主跨200米的混凝土自錨式懸索橋?yàn)檠芯勘尘?利用非線性靜動(dòng)力分析方法,采用空間有限元模型,研究了單側(cè)吊索突然斷裂對(duì)結(jié)構(gòu)受力的影響。研究表明,自錨式懸索橋吊索斷裂對(duì)相鄰吊索的拉力、主梁豎向彎矩、主梁扭矩、索塔順橋向彎矩、支座反力影響很大,采用動(dòng)力分析方法計(jì)算的結(jié)果與采用靜力分析方法得到的結(jié)果相差甚遠(yuǎn)。單側(cè)相鄰兩根吊索相繼斷裂,會(huì)使相鄰其他吊索的拉力達(dá)到初始拉力的3.0倍以上,如果設(shè)計(jì)采用的吊索安全系數(shù)較低,或吊索出現(xiàn)普遍腐蝕,單側(cè)相鄰兩根吊索斷裂會(huì)導(dǎo)致橋梁整體垮塌。及分別研究了主梁抗彎剛度、主梁抗扭剛度、主纜抗彎剛度、主梁自重、主纜自重、主纜垂跨比、吊索距離、跨度及斷索時(shí)間等參數(shù)對(duì)斷索動(dòng)態(tài)響應(yīng)的影響。最后,討論了雙吊桿結(jié)構(gòu)對(duì)斷索后結(jié)構(gòu)動(dòng)力響應(yīng)的影響,給出了提高結(jié)構(gòu)安全性的建議。
[Abstract]:The main cable of the self-anchored suspension bridge is anchored at the two ends of the main beam and exerts a huge horizontal force on the main beam. If the sling supporting the main girder breaks it may lead to the destruction of the main beam and then to the collapse of the bridge as a whole. With the increase of service time, the bearing capacity of sling decreases due to corrosion, which may lead to sudden fracture, make the structure vibrate violently, cause great changes in the internal force of the structure, and even endanger the safety of the bridge. Taking a concrete self-anchored suspension bridge with a main span of 200 meters as the research background, using the nonlinear static and dynamic analysis method and the spatial finite element model, the influence of the sudden fracture of one side sling on the structural force is studied in this paper. The research shows that the tension force, the vertical moment of the main beam, the torque of the main beam, the bending moment of the cable tower along the bridge, and the reaction force of the support have great influence on the tension force of the adjacent slings caused by the sling cable fracture of the self-anchored suspension bridge. The results calculated by dynamic analysis method are far from those obtained by static analysis method. If one side and two adjacent slings break one by one, the tension of the adjacent other slings will reach 3.0 times of the initial tensile force. If the safety factor of the slings used in the design is low, or the sling is generally corroded, The rupture of two sling cables on one side will cause the bridge to collapse as a whole. The effects of bending stiffness, torsional stiffness, bending stiffness of main cable, deadweight of main beam, ratio of vertical span of main cable, sling distance, span and time of cable breaking on the dynamic response of broken cable are studied respectively. Finally, the influence of double suspenders on the dynamic response of the structure after cable break is discussed, and some suggestions to improve the safety of the structure are given.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：U448.25

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本文編號(hào)：2327127