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Tensioning method of internal prestressed laminated wood beam

A technology of prestressing and prestressing tendons, applied in the direction of joists, girders, truss beams, etc., can solve problems such as section failure, pull-off, and danger, and achieve the effect of improving bearing capacity

Active Publication Date: 2018-04-10
SOUTHEAST UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In vivo prestressed glulam beams need to stretch the reinforcement, but the existing technology cannot determine the specific tension. When the tension is too small, the strength of the prestressed reinforcement will be small, and the fiber strength utilization rate in the compressed area of ​​the wood will be lower. The prestressed glulam beam is not high, and the flexural bearing capacity of the prestressed glulam beam is not much improved compared with the ordinary glulam beam, and the damage is sudden and brittle; when the tension is too large, the prestressed tendons are prone to premature failure under the load. It is very dangerous to yield or even break, resulting in failure of the section, and injury to people due to the ejection of the anchor clip

Method used

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  • Tensioning method of internal prestressed laminated wood beam
  • Tensioning method of internal prestressed laminated wood beam
  • Tensioning method of internal prestressed laminated wood beam

Examples

Experimental program
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Effect test

Embodiment 1

[0061] The method for determining the upper and lower limits of the effective tension force will be further described in detail below in conjunction with the accompanying drawings.

[0062] figure 1 Schematic diagram of the cross-section of an internally prestressed glulam beam. Among them, b and h are the width and height of the prestressed glulam beam respectively; h at 、h ac , are respectively the distances from the resultant force point of tension and compression bars to the edges of timber tension and compression areas; A rc is the cross-sectional area of ​​the compression bar; A rt is the cross-sectional area of ​​the tensioned prestressed tendons.

[0063] The method for determining the upper and lower limits of the effective tension force proposed by the present invention comprises the following steps:

[0064] Step 1: Make basic assumptions about the calculation, including:

[0065] (1) The average strain of the cross-section of the member is linearly distribute...

Embodiment 2

[0117] The use of the upper and lower limit formulas of the effective tensile force will be further described in detail in the following combined with a calculation example.

[0118] A simply supported beam is a linear internally prestressed glulam beam with a span of 4m. The reinforcement is only arranged in the tension area. The cross-sectional size of the beam is b×h=100×240mm. Level φ s 15.24 Low-slack steel strands. The relevant parameters of the materials are as follows.

[0119] (1) Relevant data of glulam (Douglas fir) (along the grain):

[0120] Elastic modulus: E w =11410MPa,

[0121] The ratio of tangent modulus to elastic modulus in the descending section of the compression zone: m=-0.1,

[0122] Compressive strain at yield: ε wcy = 0.321%,

[0123] Ultimate tensile strain: ε wtu = α m ·ε wmu =1.3×0.298%=0.387%,

[0124] Ultimate compressive strain: ε wcu = 0.572%.

[0125] (2) Relevant data of prestressed tendon (1860 steel strand):

[0126] Elastic ...

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Abstract

The invention discloses a tensioning method of an internal prestressed laminated wood beam. The tensioning method comprises the following steps that 1, the structural parameters of the internal prestressed laminated wood beam are obtained; 2, according to the structural parameters obtained in the step 1, the upper limit value and the lower limit value of effective tensioning force of the prestressed laminated wood beam are determined, wherein the lower limit value is effective tensioning force corresponding to the critical states of tension failure and compression failure, and the upper limitvalue is effective tensioning force corresponding to the situation that prestressed tendons are exactly yielded under the extremity state; and 3, according to the determined upper limit value and lower limit value of the effective tensioning force, the laminated wood beam is tensioned. According to the tensioning method of the internal prestressed laminated wood beam, the upper and lower limit values of the tensioning force can be directly, conveniently and accurately, so that the reasonable and effective tensioning force is determined to tension laminated wood, and the bearing capacity of thelaminated wood is improved under the premise that safety is ensured.

Description

technical field [0001] The invention relates to a method and technology for determining the upper and lower limits of the effective tensile force of prestressed glued wood beams in the body, and belongs to the technical field of wood structure design. Background technique [0002] Glued wood is a composite wood made of logs as the main raw material, using high-performance environmentally friendly adhesives, and using modern wood processing technology. Due to the advantages of energy saving and environmental protection, excellent structural performance, and the size and shape are not limited by log diameters, as early as the 1940s and 1950s, the development of glulam structures has spread throughout Europe, America, Japan and other countries, and has been widely used in large-span, Space and bridge structure. The bending failure of traditional glulam beams is mostly tensile failure caused by tension edge defects, and the strength of wood, especially the compressive strength,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E04G21/12E04C3/18
CPCE04C3/18E04G21/12
Inventor 张晋沈浩王卫昌
Owner SOUTHEAST UNIV