Method for predicting bonding strength of steel strand under cracking and failures of rotation and protection layer

A technology of bond strength and prediction method, applied in the direction of instrumentation, geometric CAD, calculation, etc., can solve the problems that the mechanical model of bond strength has yet to be developed

Active Publication Date: 2018-11-16
CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, there is currently no bond strength model that can consider the influence of the rotating bond mechanism caused by its twisted stru...

Method used

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  • Method for predicting bonding strength of steel strand under cracking and failures of rotation and protection layer
  • Method for predicting bonding strength of steel strand under cracking and failures of rotation and protection layer
  • Method for predicting bonding strength of steel strand under cracking and failures of rotation and protection layer

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Embodiment 1

[0071] see Figure 1 to Figure 6 As shown, the main method of implementing the method in this embodiment includes: first, considering the twisted structure characteristics of the steel strand, establishing a force balance equation under the constraints of the steel strand and the surrounding concrete, and deriving the bond strength and bond failure of the steel strand Then, taking into account the splitting failure of concrete and the failure of steel strand pulling rotation, the calculation expressions of the radial stress of the contact surface under the two failure modes are given, and then the steel under the two failure modes is established. A theoretical calculation model for the ultimate bonding strength of stranded wires; finally, the accuracy and feasibility of the method of the present invention are verified through existing experimental data. Specific steps are as follows:

[0072] (1) Establish the relationship expression between the ultimate bond strength and the...

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Abstract

The invention discloses a method for predicting the bonding strength of a steel strand under cracking and failures of rotation and a protection layer. The method comprises the steps that a relationalexpression between the limit bonding strength and the radial stress of a bonding failure face is established, the radial stress of the bonding failure face when concrete split bonding fails is determined, the critical radial stress of the bonding failure face when a concrete split failure is turned to a drawing rotation failure is determined, and the minimum thickness of the concrete protection layer under the critical radial pressure stress is determined. Through existing drawing experiment data related to the steel strand, the method is compared and evaluated, and in combination with the twokinds of failure modes, the precision of the method is verified. By considering a twisting spiral structure and a rotation bonding mechanism of the steel strand, the limit bonding strength of the single prestress steel strand under the two kinds of failure modes including the concrete split failure and the drawing rotation failure can be effectively simulated and predicted, and the method has high precision; the defect of research related to a prestress steel strand and concrete theoretical bonding model is overcome.

Description

technical field [0001] The invention relates to the technical field of calculation methods for the ultimate bonding strength of steel strands, in particular to a method for predicting the bonding strength of steel strands based on rotation and cracking failure of a protective layer. Background technique [0002] As prestressed concrete structures are widely used in major projects, their safety issues are becoming more and more prominent. The bonding performance between prestressed tendons and concrete is an important factor affecting the safe use of structures. The bond between steel strand and concrete mainly depends on the shear force between the two contact surfaces. The force on the interface is complex, which is affected by the strength of concrete, the thickness of the protective layer, the diameter of the steel bar, and the surface characteristics of the steel strand. At present, there are few studies on the bond model between steel strand and concrete, and most of ...

Claims

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Application Information

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IPC IPC(8): G06F17/50
CPCG06F30/17
Inventor 王磊易驹吴兵辉袁平张建仁
Owner CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY
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