大跨度悬索桥空间温度场精细分析方法

Fine Analysis Method for Spatial Temperature Field of Long-Span Suspension Bridge

为了研究悬索桥空间温度场分布及其变化规律,提出了自然环境下大跨度悬索桥空间温度场精细分析方法.首先根据构件表面所在位置和太阳入射角判断大跨度悬索桥构件外表面的遮挡状态,然后基于传热理论计算构件外表面所受辐射能,通过对构件各外表面施加辐射荷载和对流换热边界计算大跨度悬索桥空间温度场,最后以某大跨度悬索桥为例,采用多尺度分析方法计算主缆的热物性参数,在此基础上得到了自然环境下该桥空间温度场分布.结果表明,自然环境下大跨度悬索桥主缆空间温度场关于跨中非对称分布,最高温度出现在近跨中受太阳正面照射的节段,主塔迎阳面和背阳面最大温差近7,℃,桥面阴影区与相邻非阴影区温差达15,℃.以该方法为基础,可以实现大跨度悬索桥健康监测系统结构响应中温度效应的精确分离.

In order to study the spatial temperature distributions of suspension bridges in natural environment,a method for finely analyzing the spatial temperature field of long-span suspension bridges is proposed.First,the occlusion state is judged according to the position and solar incident angle of the bridge component surface.Then,the radiation energy applied on the component surface is calculated based on heat transfer theory.Through applying the solar radiation and the convective heat transfer,the spatial temperature field of long-span suspension bridge is calculated.Finally,taking a long-span suspension bridge as an example,the material parameters for thermal analysis are obtained through multi-scale analysis and the spatial temperature distributions are calculated based on those parameters.It is shown that the spatial temperature distributions of the main cable in natural environment are not symmetrical about the mid-span.The highest temperature appears in the main cable segment near the mid-span and irradiated by the sun.The maximum temperature difference between the solar radiation surface and the shaded surface of the main tower is up to 7,℃.The temperature difference between the shaded area and adjacent non-shadow area is as high as 15,℃.Based on this method,accurate separation of temperature effects in structural responses of long-span suspension bridge health monitoring system can be realized.