土方车作用下基坑栈桥等效均布活荷载分析

Analysis of Equivalent Uniform Live Load of Pit Trestle Under Dump Truck

土方车是基坑栈桥承受的主要活荷载,对栈桥的响应起控制作用。目前我国尚无土方车作用下栈桥桥面板与梁的等效均布活荷载的相关规定,多数工程以工程经验作为技术方法,指导性较差,严重影响了工程的造价和安全。为了研究土方车对栈桥的作用效应,结合实际工程,建立了有限元模型,并通过最不利荷载布置,对钢筋混凝土栈桥桥面板与主梁的等效均布活荷载进行了取值;对比分析了2种等效均布荷载的计算方法,并引入修正系数,进而提出了修正后栈桥桥面板等效均布面荷载的计算公式;基于最大内力准则和内力包络准则,综合分析了栈桥桥面板的不同宽度、厚度和长宽比对主梁等效均布活荷载取值的影响。该研究成果可为实际工程提供参考。

Being the main live load supported by the pit trestle,dump truck plays a controlling role in the response of the trestle.At present,there are no relevant provisions on the equivalent uniform live load of trestle bridge deck and beam under the action of dump truck in China.The engineering experience are taken as the technical method,which have poor guidance and seriously affect the cost and safety in most projects.Combined with the actual project,a finite element model is established in order to study the effect of dump truck on the treble bridge.The equivalent uniform live load of the bridge deck and the main beam of the reinforced concrete treble bridge is obtained by the most adverse load arrangement;Two calculation methods of equivalent uniform load are compared and analyzed.The modified coefficient is introduced.And then,the calculation formula of equivalent uniform load of trestle bridge deck after modification is put forward;Based on the maximum internal force criterion and the internal force envelope criterion,the effects of different widths,thicknesses and length-width ratios are comprehensively analyzed.The research can provide reference for practical engineering.