重载与轴温耦合对混凝土路面传力杆装置应力集中状态的影响

水泥混凝土路面缩缝传力杆装置在重载交通环境及大温差地区轴温耦合条件下易发生传荷失效现象。针对典型重载车辆轴载条件与大温差地区混凝土路面板内的温度梯度情况,通过模型分析法,研究了车辆轴载及轴温耦合条件下传力杆周边混凝土材料内的应力分布状态。提出了缓解荷载传递过程中传力杆与混凝土材料高接触应力水平的方法。研究发现:车辆轮胎与路面接触位置下方传力杆附近的应力集中区域是荷载传递过程中缩缝结构的最不利位置。严重超载车辆通过缩缝结构时,传力杆周边区域内的应力水平接近混凝土材料的承载极限。水泥混凝土路面板的正温梯度翘曲变形可与车辆的荷载应力相叠加,造成传力杆与混凝土在接触面附近产生较大的接触应力。增加传力杆直径,提高混凝土的承载面积,可显著缓解混凝土内的应力集中状态,有助于提高缩缝两侧混凝土路面板边的抗裂性能。

The Study on Stress Concentration in Dowel Bar System under Overloading Traffic Coupling with Temperature Stress

Load transfer failure of dowel bar system caused by over wheel loading and axle-load coupling with temperature stress is the main reason of shrink joints in the cement concrete pavements. Focused on the problem of transferring failure, model analysis method was used in this thesis. The stress distribution in concrete around dowel bar under different loading conditions were exploded, and the reduction method for high contact stress between dowel bar and concrete was presented. Results show that the unfavorable position of shrink joint where is the stress concentration region was located around the dowel under wheel loading, the contact interface between dowel bar and concrete was in the high-stress loading-unloading cycles during vehicle passing the shrink joint. The combined action caused by warping deformation of pavement slab and vehicle loading could is the main reason for the transferring failure of dowel bar. The recommendation is that the diameter increased of dowels could meet the pavement performance requirements, The stress concentration state of concrete and cracking risk around the dowel decreased by using of large diameter dowel bars.