Shrinkage creep and prestress loss computation method of concrete bridge

Abstract

The invention provides a shrinkage creep and prestress loss computation method of a concrete bridge. According to the invention, the shrinkage creep and prestress loss computation method of the concrete bridge, in which the time variation and the uncertainty are simultaneously considered, is obtained by analyzing the time variation of concrete through utilizing an age-adjusted effective modulus method (AEMM) and analyzing the uncertainty of the concrete through utilizing an accurate and rapidly-sampled Latin hypercube sampling (LHS) method; a prestress loss computation formula in which the time variation and the uncertainty of shrinkage creep and the interaction between the shrinkage creep and reinforcement stress relaxation are simultaneously considered is deduced according to a prestressed reinforcing steel and concrete stress balance equation and deformation coordination conditions and on the basis of the AEEM method and the LHS method; and a prestress loss computation method of the concrete bridge, in which the shrinkage creep and the stress relaxation are considered, is formed. In the structural internal force value field interval computed according to the shrinkage creep and prestress loss computation method disclosed by the invention, the unfavorable stress state of the bridge structure can be considered from multiple aspects in the designing process, so that the reliability of structure computation result is higher and the structure safety is better.

Description

technical field [0001] The invention relates to the field of bridge and culvert engineering in the transportation industry, in particular to a calculation method for shrinkage, creep and prestress loss of concrete bridges considering time variation and uncertainty. Background technique [0002] Prestressed concrete bridges have broad engineering application prospects in the field of bridge engineering due to their unique advantages such as strong spanning ability, mature construction technology, comfortable driving, low construction cost and simple maintenance. According to incomplete statistics, among the bridges built in the world, concrete bridges account for the largest proportion of all bridge types: among them, concrete bridges in Europe and the United States account for more than 70% of the bridges built; Accounted for more than 90%. With the continuous maturity of concrete bridge design and construction technology, and the continuous improvement of high-performance ...

AI Technical Summary

Problems solved by technology

The shrinkage and creep mechanism of high-strength concrete is not fully understood. The various shrinkage and creep calculation methods of bridge structures currently have a difference of more than 30% in the mid-span deflection value, and there is a significant difference between the theoretical calculation and the actual stress state of the bridge.

②The long-term prestress loss of long-span concrete bridge structure is large

These technologies have slowed down the mid-span deflection and box girder cracking to a certain extent, but these technologies are not solutions to the main causes of concrete bridge shrinkage, creep and prestress loss, so they cannot be solved fundamentally. Concrete bridge disease problem, further perfecting and improving shrinkage creep, prestress loss analysis theory and calculation method is an urgent problem to be solved at present

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