CN103758352A - Tensioning method for pre-stress steel strand - Google Patents

Abstract

The invention discloses a tensioning method for pre-stress steel strands. The tensioning method for the pre-stress steel strands includes: 1) selecting a matched anchorage device according to the strand number of each beam, mounting a clamping piece, and making the steel strands pass through the center of a jack; 2) transversely tensioning in double directions without tensioning completely, wherein the initial tensioning stress is controlled at 13% sigma con; 3) lasting for 4 minutes, and continuing to tension to arrive at 26% of the designed stress value (double initial stress); 4) lasting for 4 minutes, and continuing to tension to arrive at the designed stress value; 5) lengthwise tensioning in double directions to arrive at the initial stress 13%; 6) lasting for 4 minutes, and continuing to tension to arrive at 26% of the designed stress; 7) lasting for 4 minutes, and continuing to tension to arrive at 50% of the designed tonnage; 8) measuring the elongation and recording when the jack is tensioned to 50% from 0 again, tensioning to arrive at 100% stress, measuring and recording the final elongation value. The tensioning method for the pre-stress steel strands enables the quality of the steel strands to be improved.

Description

Prestress wire method for stretching

Technical field

The invention discloses a kind of prestress wire method for stretching.

Background technology

Prestress wire is the stranded steel cable consisting of 2,3,7 or 19 high-tensile steel wires, and through the processing (stabilization processes) that eliminates stress, is applicable to prestressed concrete or similar applications.

At present, in Bridges in Our Country construction, generally adopt prestressing techniques, but its technique more complicated, technical difficulty are larger., there is qualitatively very large problem in for example stretch-draw of prestress wire.

Summary of the invention

Technical problem to be solved by this invention is to provide a kind of prestress wire method for stretching, and the method is that the quality of steel strand is controlled.

In order to solve above-mentioned technical problem, technical scheme of the present invention is: a kind of prestress wire method for stretching, and it comprises the following steps:

1) first supporting with corresponding ground tackle by every bundle radical, be with intermediate plate, steel strand are passed from jack center;

2) laterally two directions tension does not need down top, and stretch-draw initial stress is controlled at 14% σ _con, fuel cut-off when initial stress is arrived in stretch-draw, after checking that intermediate plate situation is intact, the elongation that the dry jin of record pushes up;

3) hold lotus 4min, continuing stretch-draw is double initial stress to 26% of design stress value, measures stretch value;

4) hold lotus 4min, continue to be stretched to design stress value, measure the final stretch value of steel strand, after fastening intermediate plate, unload top;

5) when longitudinally two directions tension stretch value surpasses oil pump stroke, need to push up, during initial stress 13%, surveying record stretch value;

6) hold lotus 4min, continue stretch-draw to design stress 26% time, measure stretch value;

7) hold lotus 4min, then continue to be stretched to 50% of builder's tonnage, then measure elongation, oil return, fall top, while pushing up, note work anchor is again fastening, after work clip sheet retightens, can again carry out stretch-draw;

8) when dry jin top again measures elongation and makes a record when stretch-draw is to 50% stress again from 0, be finally stretched to again 100% stress, the final stretch value of surveying record.

The inventive method has improved the quality of steel strand, and the construction quality of whole use steel strand is also got a promotion.

The specific embodiment

First supporting with corresponding ground tackle by every bundle radical, be with intermediate plate, steel strand are passed from jack center.Laterally two directions tension does not need down top, and stretch-draw initial stress is controlled at 13% σ _con, fuel cut-off when initial stress is arrived in stretch-draw, after checking that intermediate plate situation is intact, the elongation that the dry jin of record pushes up.

Hold lotus 4min, continuing stretch-draw is double initial stress to 26% of design stress value, measures stretch value, holds lotus 4min, continues to be stretched to design stress value, measures the final stretch value of steel strand, after fastening intermediate plate, unloads top.

When longitudinally two directions tension stretch value surpasses oil pump stroke, need to push up, during initial stress 13%, surveying record stretch value, holds lotus 4min, continue stretch-draw to design stress 26% time, measure stretch value, hold lotus 4min,

Then continue to be stretched to 50% of builder's tonnage, then measure elongation, oil return, fall top, while pushing up, note work anchor is again fastening, after work clip sheet retightens, can again carry out stretch-draw.

When dry jin top again measures elongation and makes a record when stretch-draw is to 50% stress again from 0, be finally stretched to again 100% stress, the final stretch value of surveying record.

Above-described embodiment does not limit the present invention in any way, and every employing is equal to replaces or technical scheme that the mode of equivalent transformation obtains all drops in protection scope of the present invention.

Claims (1)

1. a prestress wire method for stretching, is characterized in that comprising the following steps:

1) first supporting with corresponding ground tackle by every bundle radical, be with intermediate plate, steel strand are passed from jack center;

2) laterally two directions tension does not need down top, and stretch-draw initial stress is controlled at 13% σ _con, fuel cut-off when initial stress is arrived in stretch-draw, after checking that intermediate plate situation is intact, the elongation that the dry jin of record pushes up;

3) hold lotus 4min, continuing stretch-draw is double initial stress to 26% of design stress value, measures stretch value;

4) hold lotus 4min, continue to be stretched to design stress value, measure the final stretch value of steel strand, after fastening intermediate plate, unload top;

5) when longitudinally two directions tension stretch value surpasses oil pump stroke, need to push up, during initial stress 13%, surveying record stretch value;

6) hold lotus 4min, continue stretch-draw to design stress 26% time, measure stretch value;

7) hold lotus 4min, then continue to be stretched to 50% of builder's tonnage, then measure elongation, oil return, fall top, while pushing up, note work anchor is again fastening, after work clip sheet retightens, can again carry out stretch-draw;

8) when dry jin top again measures elongation and makes a record when stretch-draw is to 50% stress again from 0, be finally stretched to again 100% stress, the final stretch value of surveying record.