机场滑行道桥桥面板横向有效分布宽度分析

为确保机场滑行道桥受力安全,有必要研究滑行桥桥面板的横向有效分布宽度的合理取值。本文建立机场滑行桥桥面板三维数值精细化分析模型,利用损伤塑性本构模型模拟混凝土材料非线性,分析了A380、B747和A300三种机型轮载作用下滑行桥桥面板的横向有效分布宽度取值。分析结果表明：采用数值精细化分析方法得到的飞机轮载作用下滑行道桥桥面板的横向有效分布宽度较采用公路桥规的计算值增大,如飞机轮载作用于桥面板跨中时横向有效分布宽度增幅为18%；桥面板横向有效分布宽度取值随机型不同而存在差异,如A380和B747机型作用时得到的横向有效分布宽度分别为1.64m和1.52m；当考虑飞机轮载作用下桥面板塑性发展时,桥面板横向有效分布宽度计算值较材料弹性状态而言增大,如飞机轮载作用于桥面板跨中时横向有效分布宽度增幅为8.5%,说明飞机轮载作用时桥面板进入非线性受力状态而出现内力重分布,所以计算飞机轮载下滑行道桥桥面板横向有效分布宽度的合理取值应考虑材料非线性。

Analysis of Transverse Effective Distribution Width of Airport Taxiway Bridge Deck

To ensure the safety of airport taxiway bridge, it is necessary to study the reasonable value of the effective transverse distribution width of the taxiway bridge deck under the action of aircraft wheel load action. A three-dimensional refine numerical analysis model of the taxiway bridge deck in the airport is established. Considering the nonlinear characteristics of concrete by damage plastic constitutive model, the effective transverse distribution width of the taxiway bridge deck under the action of wheel load of different aircraft types is analyzed based on the three aircraft types of A380, B747 and A300. Analysis results indicate that: the effective transverse distribution width of taxiway bridge deck under the action of aircraft wheel load obtained by refined numerical analysis is larger than that calculated by concrete bridge gauge, such as the increase amplitude of transverse effective width is 18% when the wheel load acts on the middle span of the bridge deck. The transverse effective width of bridge deck is change with the aircraft type, such as the transverse effective width of bridge deck under A380 and B747 action are 1.64 m and 1.52 m respectively. When considering the plastic stress of the bridge deck under the action of aircraft wheel load, the calculated value of the transverse effective distribution width of the bridge deck is larger than that of considering the elastic state of the material, such as the increase amplitude of transverse effective width is 8.5% when the wheel load acts on the middle span of the bridge deck. Because the bridge deck locates on the nonlinear state when the aircraft wheel load is large, the redistribution of the internal force occurs. The material nonlinearity should be considered in the calculation of transverse effective distribution width of taxiway bridge deck under aircraft wheel load.