Abstract:

Large span cable-stayed bridges have small structural stiffness and large deformation. In order to ensure the naturally closure of each segment on the main girders, the plane position and vertical alignment must be quickly and accurately located. Distinguished from the traditional method of polar coordinates measuring the girder plane, we propose a free station method used to measure the plane of girder. At the same time, different from the traditional level measurement, the method of measuring the girder vertical line using the total station indirect height difference is proposed. The paper first introduces the measurement principle of two new methods, and finally demonstrates the feasibility and practicability of the new method through a engineering example,which can greatly improve the measurement efficiency. It can provide a reference for the monitoring of other large span girders.

Key words: large span cable-stayed bridge, main girder alignment survey, total station, free station survey, indirect height difference