带钢板-混凝土组合桥面板的组合梁疲劳性能试验研究

为研究带钢板-混凝土组合桥面板的组合梁在疲劳荷载下的受力性能,对2个试件进行静力试验研究,并对6个试件进行等幅疲劳试验研究。疲劳试验试件按承受正弯矩和承受负弯矩两组类型试件分别考虑,在各组试件中均主要考察疲劳荷载上、下限值及疲劳荷载幅值等因素对带钢板-混凝土组合桥面板组合梁的疲劳破坏模式及疲劳累积损伤的影响。疲劳试验过程中对组合梁试件在各主要循环加载次数下的动挠度、残余挠度、混凝土应变、底部钢板应变、试件钢梁应变及试件受弯刚度进行试验测量和分析。疲劳试验结果表明:正弯矩组合梁试件的疲劳破坏形态为组合梁底部钢梁疲劳断裂破坏,进而受压区混凝土压碎破坏,试件疲劳寿命主要与试件疲劳应力幅有直接关系,而疲劳荷载的上、下限值对疲劳寿命影响较小;负弯矩组合梁试件在200万次循环荷载下均未发生疲劳破坏且仍具有较高承载能力和刚度,表现出了良好疲劳性能。研究成果可为该类型组合梁设计应用提供依据。

Experiment study on fatigue behavior of composite girders with steel plate-concrete composite bridge decks

In order to study the fatigue behaviour of the steel plate-concrete composite-deck composite girders under the fatigue load,constant-amplitude fatigue tests of six specimens of the steel plate-concrete composite-deck composite beam were carried out and static loading experiments of two specimens were conducted.The influence of the main factors including the upper and lower limits of fatigue load and the stress amplitude on the failure modes and the fatigue damage extent of composite girders under fatigue load were focused on.The dynamic deflection,strains of concrete and steel plates,strains of steel beam,residual deflection and residual bearing capacity were measured and analyzed.From the tests results,the fatigue life-spans of the composite girders specimens were directly related with their stress amplitudes,but the upper and lower limits of fatigue load had little effect.With regard to the fatigue failure modes of the composite girders specimens,positive moment composite girders were all failed due to collapse of the steel beam and crush of concrete of compressive zone,but not to the negative moment of composite girders,as a result of steel-beam buckling under static tests after fatigue tests.This paper were very helpful for this type of compsite girders design.