基于叠层连续梁模型的钢桥面沥青铺装轴载换算方法

Conversion Method of Axle-load for Asphalt Pavement on Steel Deck Based on Continuous Laminated Beam Model

为完善钢桥面沥青铺装设计方法,对轴载换算方法进行了研究。在现行沥青路面设计规范轴载换算方法的基础上,基于不同铺装材料疲劳试验结果,提出轴载换算指数n的建议值。在此基础上,有别于现行规范固定轴载换算计算参数的方法,提出根据铺装材料的不同,选用动态轴载换算参数的理念。采用构造纵桥向单位荷载作用下跨中横桥向荷载弯矩影响线的方法,修正叠层连续梁模型的荷载参数与当量支承刚度参数。利用修正后的叠层连续梁模型,得到轴数系数C1的计算公式。在考虑铺装材料疲劳性能的基础上,利用叠层连续梁模型计算得到轮组系数C2的建议取值。计算结果表明,除现行规范考虑的轴距与轮距外,横隔板间距、U肋间距等对钢桥面沥青铺装的轴载换算有显著影响,采用现行规范参数带来的最大计算误差可能达17倍。

A For the purpose of perfect the design method of steel deck asphalt pavement, the axle-load conversion method was researched. According to the axle-load conversion method in current design criteria of asphalt pavement, the suggested axle-load conversion index n was put forward based on the fatigue test results of different pavement materials. Based on the suggested value, a new design idea of choosing dynamic axle- load conversion coefficient which being determined by pavement materials was proposed. This new idea is different from using the axle-load conversion parameter specified in current specification. An influence line model of lateral moment in mid-span under longitudinal unit-load was used to modify the load parameters and equivalent support stiffness parameters of continuous laminated beam model. By using the modified continuous laminated beam model, the calculation formula of axle-number coefficient C~ was obtained. Based on the fatigue property of pavement material and the continuous laminated beam model, the suggested wheel- number coefficient C2 was obtained. The calculated result shows that besides the wheel-distance and axle- distance in current design specification, the intervals of diaphragms and U stiffeners have significant effect on axle-load conversion. The maximum calculation error using parameters in current specification may be 17 times.