栓釘連接件疲勞損傷導致的組合梁力學性能退化機理研究
發(fā)布時間:2018-10-13 10:41
【摘要】:鋼-混凝土組合梁充分發(fā)揮材料性能,施工方便,已被廣泛應用于橋梁工程中。栓釘連接件通常以集群的形式布置于鋼梁上翼緣,界面剪力在栓釘連接件集群中分布不均勻。在疲勞荷載作用下,栓釘連接件的界面滑移量增加,抗剪剛度減小,從而引起界面剪力重分布。上述過程隨疲勞荷載次數(shù)的增加而不斷發(fā)展,具體表現(xiàn)為鋼-混凝土界面滑移量不斷增大,組合梁撓度不斷增加。本文的主要研究內(nèi)容和結論為:一、對三根鋼-混凝土組合梁試件進行疲勞試驗,研究剪力鍵剪切破壞為表征的鋼-混凝土組合梁的疲勞破壞機理及疲勞損傷過程。試驗得到以下結論:鋼-混凝土組合梁的疲勞壽命對疲勞荷載相當敏感,疲勞荷載幅值及疲勞荷載峰值都會顯著影響組合梁的疲勞壽命;根據(jù)組合梁的撓度及剪力鍵群的抗剪剛度演化規(guī)律,可以將剪力鍵剪切破壞為表征的鋼-混凝土組合梁的疲勞損傷三個階段;剪力鍵群的抗剪性能退化是與單個剪力鍵的疲勞損傷相耦合的動態(tài)過程;組合梁的撓度變化不一定能反映其內(nèi)部損傷。二、考慮栓釘連接件的非線性荷載-滑移關系,基于受彎條件下簡支組合梁的界面滑移量和荷載的協(xié)調(diào)方程,建立鋼-混凝土組合梁界面"非連續(xù)傳力"模型,并使用MATLAB編程求解栓釘連接件的滑移量和承擔的剪力,計算結果與數(shù)值模型吻合良好。參數(shù)分析發(fā)現(xiàn),增大界面抗剪剛度能夠提高組合梁的剛度,但不能無限制提高。三、基于疲勞加載后栓釘連接件界面殘余滑移量的發(fā)展,將疲勞荷載作用下栓釘連接件的抗剪剛度退化模型引入"非連續(xù)傳力"模型中,研究疲勞荷載作用下,界面剪力在栓釘連接件集群中的重分布和組合梁剛度退化現(xiàn)象。分析表明,疲勞加載不僅使鋼-混凝土界面剪力減小而且使其在栓釘連接件集群中分布更均勻;組合梁跨中撓度隨疲勞加載的進行近似線性增長。
[Abstract]:Steel-concrete composite beam has been widely used in bridge engineering because of its material properties and convenient construction. Stud joints are usually arranged in clusters on the flange of steel beams, and the interfacial shear forces are distributed inhomogeneously in the cluster of bolt connectors. Under fatigue load, the interfacial slip of the stud joint increases and the shear stiffness decreases, which results in the redistribution of the interfacial shear force. The above process develops with the increase of fatigue load times, which is manifested by the increasing slip at the steel-concrete interface and the increasing deflection of composite beams. The main contents and conclusions of this paper are as follows: first, the fatigue failure mechanism and fatigue damage process of steel-concrete composite beams characterized by shear bond shear failure are studied. The results show that the fatigue life of steel-concrete composite beams is very sensitive to fatigue load, and the amplitude of fatigue load and the peak value of fatigue load will significantly affect the fatigue life of composite beams. According to the evolution law of deflection of composite beam and shear stiffness of shear bond group, the fatigue damage of steel-concrete composite beam can be characterized by shear bond shear failure. The degradation of shear behavior of the shear bond group is a dynamic process coupled with the fatigue damage of a single shear bond, and the deflection change of the composite beam may not necessarily reflect the internal damage. Secondly, considering the nonlinear load-slip relationship of stud connections, a discontinuous force transfer model at the interface of steel-concrete composite beams is established based on the equations of interface slip and load coordination of simply supported composite beams under bending conditions. The slippage and shear force of the stud joint are calculated by MATLAB program. The calculated results are in good agreement with the numerical model. Parameter analysis shows that the stiffness of composite beam can be improved by increasing the shear stiffness of interface, but it can not be increased without restriction. Thirdly, based on the development of residual slip at the interface of the stud joint after fatigue loading, the degradation model of shear stiffness is introduced into the "discontinuous force transfer" model under fatigue load. The redistribution of interfacial shear forces and stiffness degradation of composite beams in the cluster of stud connectors. The analysis shows that the fatigue loading not only reduces the shear force at the interface between steel and concrete but also makes it distribute more evenly in the cluster of stud joints, and the mid-span deflection of composite beam increases linearly with fatigue loading.
【學位授予單位】:西南交通大學
【學位級別】:碩士
【學位授予年份】:2017
【分類號】:U441
本文編號:2268325
[Abstract]:Steel-concrete composite beam has been widely used in bridge engineering because of its material properties and convenient construction. Stud joints are usually arranged in clusters on the flange of steel beams, and the interfacial shear forces are distributed inhomogeneously in the cluster of bolt connectors. Under fatigue load, the interfacial slip of the stud joint increases and the shear stiffness decreases, which results in the redistribution of the interfacial shear force. The above process develops with the increase of fatigue load times, which is manifested by the increasing slip at the steel-concrete interface and the increasing deflection of composite beams. The main contents and conclusions of this paper are as follows: first, the fatigue failure mechanism and fatigue damage process of steel-concrete composite beams characterized by shear bond shear failure are studied. The results show that the fatigue life of steel-concrete composite beams is very sensitive to fatigue load, and the amplitude of fatigue load and the peak value of fatigue load will significantly affect the fatigue life of composite beams. According to the evolution law of deflection of composite beam and shear stiffness of shear bond group, the fatigue damage of steel-concrete composite beam can be characterized by shear bond shear failure. The degradation of shear behavior of the shear bond group is a dynamic process coupled with the fatigue damage of a single shear bond, and the deflection change of the composite beam may not necessarily reflect the internal damage. Secondly, considering the nonlinear load-slip relationship of stud connections, a discontinuous force transfer model at the interface of steel-concrete composite beams is established based on the equations of interface slip and load coordination of simply supported composite beams under bending conditions. The slippage and shear force of the stud joint are calculated by MATLAB program. The calculated results are in good agreement with the numerical model. Parameter analysis shows that the stiffness of composite beam can be improved by increasing the shear stiffness of interface, but it can not be increased without restriction. Thirdly, based on the development of residual slip at the interface of the stud joint after fatigue loading, the degradation model of shear stiffness is introduced into the "discontinuous force transfer" model under fatigue load. The redistribution of interfacial shear forces and stiffness degradation of composite beams in the cluster of stud connectors. The analysis shows that the fatigue loading not only reduces the shear force at the interface between steel and concrete but also makes it distribute more evenly in the cluster of stud joints, and the mid-span deflection of composite beam increases linearly with fatigue loading.
【學位授予單位】:西南交通大學
【學位級別】:碩士
【學位授予年份】:2017
【分類號】:U441
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