传力杆偏位对机场道面水泥混凝土应力的影响

Influence of dowel bar misalignment on stress on cement concrete in airport pavement

传力杆偏位会造成机场道面水泥混凝土应力集中,更容易破坏道面传荷结构。针对该问题,建立了机场水泥混凝土道面传力杆偏位有限元模型,分析了温度收缩和飞机荷载两种作用方式下多种偏位工况的混凝土应力集中规律。仿真结果表明:温度收缩时,随着接缝宽度越大,最大主应力近似线性增长,偏位角度越大,增长速率越大;飞机荷载作用下,传力杆水平偏位对裹附混凝土的应力集中影响可以忽略,但竖向偏位时影响明显,尤其双杆异向偏位时应力变化程度最大,工况最为不利。通过试验对单根传力杆偏位的有限元结果进行了验证,验证结果表明:荷载下传力杆露出混凝土部分背向荷载作用点方向旋转偏位工况下结构承载力大幅降低,建议在施工中应采取措施保证传力杆不发生竖向偏位。

The bar misalignment will cause stress concentration on airport cement concrete pavement,and it is easier to damage the load transfer structure of pavement.In order to solve this problem,a finite element model of dowel bar misalignment on airport cement concrete pavement is established,and the stress concentration law of concrete under various misalignment conditions with temperature contraction and aircraft load is analyzed.Simulation results show that when temperature contraction happens,the maximum principal stress increases approximately linearly with the increase of the seam width,and the greater the deflection angle,the bigger the growth rate.Under the action of aircraft load,the influence of horizontal dowel bar misalignment on the stress concentration of the wrapped concrete can be ignored,but the influence is obvious in the case of vertical deflection,especially in the case of opposite misalignment of twin bars,the change of stress is the largest and the working condition is the most unfavorable.Through the test,the results of finite element model of a single dowel bar misalignment are verified.The verification results show that under the load,the bearing capacity of the structure is greatly reduced when the exposed part of the dowel bar turns away from the direction of the load action point.It is suggested that measures are taken in the construction to ensure that the dowel bar does not have vertical misalignment.