Method for determining elastic modulus and flexural rigidity of reinforced concrete beam with crack

Abstract

The invention discloses a method for determining the elastic modulus and flexural rigidity of a reinforced concrete beam with a crack, relating to a tension Young's elastic modulus of a reinforced concrete beam with a crack in working, a measuring method of the tension Young's elastic modulus and a determining method of the flexural rigidity. A reinforced concrete beam with a rectangular cross section is manufactured as a test piece to be detected, and the length, width and height of the reinforced concrete beam are shown in the specification; the two ends of the test piece are supported by hinged supports; loads are intensively and symmetrically applied on the positions some distance away from at two points of the supports; the deflection value of the middle part of the test piece span and the strain value of the lowest end of the middle part of the test piece span are detected; a sum computed expression is deduced according to the analytic solution which is given by at theory of different tension-compression modulus under the condition that loading is performed on two points of a simple beam with a rectangular section intensively and symmetrically; and the sum can be accurately calculated by the load value, the defection value and the strain value. The sum determined by the invention contains a crack factor of the reinforced concrete beam within the given load range, and can be used for structural mechanic accurate analysis.

Description

technical field [0001] The present invention relates to Young's modulus of elasticity in tension for reinforced concrete beams working with cracks and Young's modulus of elasticity under compression The measurement method and the bending stiffness method of determination. Background technique [0002] The prefabricated reinforced concrete beams are used for loading tests to measure Young's modulus of elasticity and flexural stiffness, which has guiding significance for the design theory of reinforced concrete structures. At present, the measurement of the elastic modulus and the determination of the flexural stiffness of reinforced concrete beams are mostly based on the classic theory of equal modulus elasticity, that is, under the same absolute value of tensile and compressive stress, the material will produce the same absolute value of tensile and compressive strain. A large number of tests and studies have shown that under the same absolute value of tensile stress o...

AI Technical Summary

Problems solved by technology

Therefore, still using the classic equal modulus elasticity theory to determine the flexural stiffness of cracked reinforced concrete beams will inevitably cause excessive calculation errors, which is not conducive to the rational design of engineering structures

Images