Determination Method of Suspension Bridge Main Cable Sag and Tower Top Horizontal Displacement with Temperature

Abstract

The invention provides a method for determining the sag of a main cable of a suspension bridge and the horizontal displacement of a tower top as a function of temperature, and belongs to the technical field of bridge structure analysis and monitoring. In this method, the sag change and span change of the main cable at each span are taken as unknown quantities, and the horizontal tension of the main cable on both sides of the tower top is equal, the geometric relationship between the main cable shape and the length of the main cable, and the span of the main cable at each span. Based on the boundary conditions that the sum of the distances needs to meet, a linear equation system is constructed to solve the variation of the main cable sag and the horizontal displacement of the tower top with temperature at each span. When calculating the temperature deformation of the suspension bridge, this method takes into account the contribution of the main cable and the bridge tower, and takes into account the sag of the side-span main cable, which has high accuracy. This method can calculate the temperature deformation only based on the overall size of the suspension bridge, guide the layout of the measuring points of the suspension bridge monitoring system, and provide prior knowledge for the establishment of the temperature deformation benchmark model. The invention can be extended to the temperature deformation analysis of suspension cable structures such as power transmission lines and cable cars.

Description

technical field [0001] The invention relates to the technical field of bridge structure analysis and monitoring, in particular to a method for determining the sag of a main cable of a suspension bridge and the horizontal displacement of a tower top as the temperature changes. Background technique [0002] The shape change of the main cable is the focus of attention in the monitoring of the suspension bridge during the operation period, which can be characterized by the sag of the main cable and the horizontal displacement of the tower top. On-site monitoring found that the shape of the main cable of the suspension bridge will change significantly with the change of ambient temperature, thereby covering up the abnormal deformation of the structure caused by structural damage or degradation. If the normal temperature-related deformation can be eliminated from the measured total deformation, the abnormal deformation of the structure can be highlighted, and its health status can...

AI Technical Summary

Problems solved by technology

Regression analysis does not reflect the causal relationship between variables, and the obtained model is only for a specific bridge, which has poor versatility; finite element analysis requires detailed design information and necessary professional knowledge, and different bridges need to be modeled separately, which also has the disadvantage of poor model versatility; Although the physical mechanism formula is an approximate estimate, it has a clear concept, strong versatility, convenient parameter analysis and on-site calculation, and has advantages that the previous two methods do not have

However, the physical mechanism formulas for the temperature deformation of suspension bridges are few and incomplete

The calculation of the sag of the main cable of the mid-span either adopts the deformation formula of a single suspension cable, or ignores the sag effect of the main cable of the side-span, and the calculation formula of the horizontal displacement of the tower top is rarely reported.

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