混凝土梁式桥立面线形的修正方法

Modification Method for Vertical Geometric Shape of Concrete Beam Bridge Deck

由于计算参数、计算理论、计算模型、计算方法与实际条件的差别及施工误差等原因,混凝土梁式桥施工完成后,实际的桥面线形与设计目标不一致,需通过适当调整调平层或铺装层厚度修正目标线形,保证立面线形匀顺。匀顺的立面线形为在设计的凸曲线范围内没有凹曲线,反之亦然。修正方法是测量多个离散点的高程,2个端点的铺装厚度按与接线设计高程一致计算,其余点的初始高程先按最小铺装层厚度计算,然后用逐点判别凹凸性来调整目标高程,再根据目标高程计算铺装层厚度,从而使全桥线形凹凸性一致,调整后的调平层和铺装层厚度在合理范围内。调平层和铺装层施工宜按厚度控制,避免铺装施工过程中高程变化对测量的影响。

Owing to the differences between the calculation parameters,theory,models and methods and the actual conditions and also owing to the construction errors,the actual vertical geometric shape of concrete beam bridge deck may not agree with that of the design target after the bridge is constructed.To ensure the smoothness of the vertical geometric shape of the deck,the target geometric shape needs to be modified by appropriately adjusting the leveling layer or deck surfacing thickness.The smoothness of the vertical geometric shape means that within the range of the designed convex curve,there should be no concave curve and vice visa.To be specific,the modification method is used to measure the elevation of a number of discretion points.The deck surfacing thickness at the two end points is calculated according to the agreement of the thickness with the designed elevation of route alignment.The initial elevation of the rest of the points is firstly calculated according to the minimum deck surfacing thickness,the target elevation is adjusted by identifying the convex and concave point by point,the deck surfacing thickness is then calculated according to the target elevation and consequently the convex and concave of the whole bridge are kept agreeable and the adjusted leveling layer or deck surfacing thickness is kept within the rational range.The construction of the leveling layer or deck surfacing thickness should be preferably carried out according to the thickness control and the influence of variation of elevation in the construction process on the measurement should be avoided.