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A Prestressed Tendon Element with Inelastic Shrinkage

A prestressed tendon, inelastic technology, applied in the field of mechanics, can solve problems such as inability

Inactive Publication Date: 2017-01-11
CHONGQING JIAOTONG UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide a kind of prestressed tendon unit containing inelastic shrinkage, aiming at solving the problem that the current simulation method for prestressing can not be used to simulate the pretensioned prestressed tendon, considering the loss of prestressed force caused by the elastic compression of concrete, It can also be used to simulate post-tensioned prestressed tendons, and accurately simulate the effective prestress of prestressed tendons after various losses are included

Method used

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  • A Prestressed Tendon Element with Inelastic Shrinkage
  • A Prestressed Tendon Element with Inelastic Shrinkage
  • A Prestressed Tendon Element with Inelastic Shrinkage

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0109] Statically indeterminate truss:

[0110] for image 3 For the planar truss structure shown, the cross-sectional area of ​​each rod is A=0.002m 2 , elastic modulus E=200GPa, fixed hinge support at node 1, and movable hinge support with vertical constraints at node 2. Now it is desired to stretch a prestressed tendon with the same cross-sectional area and material as other rods between nodes 1 and 5, and between nodes 2 and 3 (such as Figure 4 ), and the tensile stress is 100MPa. After the prestress is applied, a vertical downward concentrated force of 1000kN is applied to nodes 3, 5, and 6.

[0111] Using two-node truss elements, different methods are used to simulate the mechanical state of the structure plus prestressed tendons after tension.

[0112] (1) Using the equivalent load method, the calculation model is image 3 , a relative tensile force equivalent to the prestress can be applied between nodes 1 and 5, and between nodes 2 and 3: F=Aσ=200kN. The calcula...

Embodiment 2

[0127] plane problem

[0128] Such as Figure 5 and Figure 6 The simply supported beam of the planar problem shown, the structural size is 1.2x0.2m, the thickness is 0.01m, and the modulus of elasticity of concrete is E c =2e10Pa, Poisson's ratio μ c =0.1667, now it is desired to stretch a prestressed tendon at a distance of 0.02m from the lower boundary, and the cross-sectional area of ​​the tendon is A=0.0001m 2 , the steel elastic modulus E s =2e11Pa, Poisson's ratio μ s =0.3, the thermal expansion coefficient of the material is α=1.0e-5 / ℃, the rib unit is divided into 6 equal parts, and the tensile stresses of each section from left to right are 200MPa, 210MPa, 220MPa, 20MPa, 240MPa, 250MPa, in the prestress After the application is completed, continue to apply a vertical downward concentrated force of 10kN on each node of the upper boundary. Three methods are used (four-node elements are used for planar elements) to simulate the mechanical state of the structure pl...

Embodiment 3

[0150] space problem

[0151] Such as Figure 7 and Figure 8 The simply supported beam shown in the plane problem has a structural size of 1.2x0.2m, a thickness of 0.01m, and a concrete modulus of elasticity E c =2e10Pa, Poisson's ratio μ c =0.1667, now it is desired to stretch a prestressed tendon at a distance of 0.02m from the lower boundary, and the cross-sectional area of ​​the tendon is A=0.0001m 2 , the steel elastic modulus E s =2e11Pa, Poisson's ratio μ s =0.3, the thermal expansion coefficient of the material is α=1.0e-5 / ℃, and the tensile stresses of the 01, 12, 23, 34, 45, and 56 sections are 200MPa, 210MPa, 220MPa, 20MPa, 240MPa, respectively. 250MPa; After the prestress tension is completed, a vertically downward concentrated load of 10kN is applied to each of the three nodes on the upper surface of the beam span that is equally divided along the thickness. The concrete adopts 20-node space unit, and the prestressed tendon is divided into 12 units equally ...

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Abstract

The invention discloses a pre-stress tendon unit with the inelasticity contraction amount. The pre-stress tendon unit with the inelasticity contraction amount is divided into a pre-stress tendon unit body under an axis coordinate system, a pre-stress tendon unit body under a plane coordinate system and a pre-stress tendon unit body under a space coordinate system. As for the pre-stress tensioning state, nodal displacement obtained by the pre-stress tendon unit is coincident with computed results of an equivalent load method, and the stress values of pre-stress tendons are coincident with anticipatory effective pre-stress values; when reloading is carried out, the nodal displacement increment and tendon unit stress increment obtained by the pre-stress tendon unit are coincident with results of a solid force tendon method; the pre-stress tendon unit can be used for simulating pre-tensioned pre-stress tendons, pre-stress losses caused by elastic compression of concrete are considered, the pre-stress tendon unit can also be used for simulating post-tensioned pre-stress tendons, and the effective pre-stress of the pre-stress tendons after the various losses are included and reloading can be accurately simulated.

Description

technical field [0001] The invention belongs to the field of mechanics, in particular to a prestressed tendon unit with inelastic shrinkage. Background technique [0002] Prestressed concrete structures are widely used in civil engineering, especially bridge engineering. It is of great significance to accurately reveal and simulate its real mechanical state through finite element numerical method for the safety of prestressed concrete structures. [0003] The key issue in the finite element method analysis of prestressed concrete structures is how to properly model the prestressed tendons. At present, there are mainly equivalent load method and solid force tendon method for the simulation of prestressed tendons. [0004] The equivalent load method is to remove the prestressed tendons from the structure, and replace the effect of the prestressed tendons on the concrete with a group of equivalent loads. The advantage of this method is that it can truly simulate the linear sh...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F19/00
Inventor 王家林何琳
Owner CHONGQING JIAOTONG UNIVERSITY