CN105569265A - Technology for reduction of beam section height by use of unbonded steel strand prestress - Google Patents
Technology for reduction of beam section height by use of unbonded steel strand prestress Download PDFInfo
- Publication number
- CN105569265A CN105569265A CN201510981989.3A CN201510981989A CN105569265A CN 105569265 A CN105569265 A CN 105569265A CN 201510981989 A CN201510981989 A CN 201510981989A CN 105569265 A CN105569265 A CN 105569265A
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- bending
- prestressing
- steel cable
- steel
- section height
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C3/00—Structural elongated elements designed for load-supporting
- E04C3/02—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces
- E04C3/20—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of concrete or other stone-like material, e.g. with reinforcements or tensioning members
- E04C3/26—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of concrete or other stone-like material, e.g. with reinforcements or tensioning members prestressed
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
- E04C5/08—Members specially adapted to be used in prestressed constructions
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- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Reinforcement Elements For Buildings (AREA)
Abstract
The present invention discloses a method for reduction of beam section height by use of unbonded steel strand prestress, the method comprises reduction of the beam section height by use of external prestress and reduction of the beam section height by use of internal prestress, when the number of desired steel strands is not more than 6, or the number of desired steel strands is more than 6, but anchoring of both ends can be treated, an external prestress method is used; and when the number of the desired steel strands is greater, and anchoring of ends of the steel strands cannot be treated, an internal prestress method is used. The method is simple in construction, uninstall and additional arrangement of a temporary support are not needed, construction period is short, cost is low, an upper structure is not affected, and the method has the advantages that service life is synchronous with that of an original structure.
Description
Technical field
The present invention relates to construction work transformation field, specifically non-bending steel cable prestressing force reduces the technology of beam section height, and point external prestressing reduces beam section height technology and prestressing with bond reduces beam section height technology.
Background technology
Steel bar concrete crossbeam is the component bearing floor plate load.When needing the depth of section reducing beam, the positive reinforcement of beam must remove, and only leaves negative reinforcing bar.The supporting capacity of beam is inevitable not enough, and the rigidity of beam is also by wretched insufficiency.In this case reinforcing and processing method is current or blank.
Summary of the invention
The object of the present invention is to provide the technology that can reduce beam section height, and the depth of section of beam reduces can not affect superstructure later.
For achieving the above object, the invention provides following technical scheme:
When required steel strand quantity no more than 6, or more than 6 but two ends anchoring can process time adopt external prestressing technique.Adopt the non-bending steel cable of tri linear shape, base is held the steel being located at soffit of girder portion and is hung rod, produces the moment of flexure that reverse bending moment balances external load, then the lower section of beam removed after prestressed stretch-draw;
When the steel strand quantity needed is more, prestressing with bond technology is adopted when steel strand end anchorage cannot process, respectively arrange a non-bending steel cable prestressing with bond crossbeam in former crossbeam both sides, height is identical with the beam reduced after beam section height, by stirrup and connecting lacing wire, three is linked to be entirety.Steel strand are shape parabolically.After prestressed stretch-draw, produce the moment of flexure that reverse bending moment balances the generation of whole standard dead load, then the lower section of former crossbeam is removed;
As the further scheme of the present invention: when adopting non-bending steel cable external prestressing to reduce beam section height, on the pillar that two ends round buss three intermediate plate of steel strand or two clip type single hole anchor devices are anchored at end or on the reinforced concrete beam vertical with pillar, or anchor is on steel pin rod.Steel strand adopt ultimate strength to be 1860N/mm
2u Φ
j15.2 underrelaxation non-bending steel cable.Span centre steel hangs rod and adopts Φ 50 thick walled steel tube, interior filling fine-stone concrete.Steel hangs 50mm at the bottom of rod to the beam reduced behind cross section, and when there being number row steel strand, the distance up and down that steel hangs rod is not less than 30mm, can pass through side by side to make steel strand.The reverse bending moment figure that the horizontal range that steel hangs rod should make prestressing force produce as far as possible is consistent with the load moment of flexure figure of beam.
As the further scheme of the present invention: when described non-bending steel cable external prestressing reduces beam section height, produce excessive antiarch in order to avoid reducing beam section height, prestressing force only needs tension metrics load later.Supporting capacity insufficient section can be born by negative reinforcing bar, also can consider beam section compressive stress that prestressing force produces disappear pressure time required moment of flexure.
As the further scheme of the present invention: when described non-bending steel cable external prestressing reduces beam section height, when removing the lower section of beam, the stirrup of former crossbeam being retained a part, is welded to each other after bending, then template is set, pour into grouting material; Steel strand overcoat white flame-proof PVC pipe, steel hangs rod and end anchorage C30 fine-stone concrete parcel, and the application life making beam reduce depth of section later is synchronous with original structure.
As the further scheme of the present invention: when described non-bending steel cable prestressing with bond reduces beam section height, after the non-bending steel cable prestressing with bond crossbeam established to configure the un-bonded prestressed steel strand of parabolically shape and the non-prestressed plain bars of linearly shape simultaneously.The moment of flexure that whole standard dead load produces only born by prestress wire, and supporting capacity insufficient section is by non-prestressed positive reinforcement and negative reinforcing bar, and the negative reinforcing bar of original crossbeam is supplied, and can avoid like this producing excessive antiarch.
As the further scheme of the present invention: when described non-bending steel cable prestressing with bond reduces beam section height, be linked to be entirety by stirrup and connecting lacing wire between the non-bending steel cable prestressing with bond crossbeam newly established and former crossbeam.After former crossbeam lower section is removed, leave a part of stirrup, be welded to each other after bending, plaster closed by 1: 2 cement mortar.End anchorage wraps up with C30 fine-stone concrete after stretch-draw.
As the further scheme of the present invention: when described non-bending steel cable prestressing with bond reduces beam section height, the width of the non-bending steel cable prestressing with bond crossbeam newly established will be determined according to the layout of steel strand.When two row arranged by every side steel strand of beam, the width of every curb girder is not less than 150mm, 200mm is not less than when layout three arranges, often increase by a row minimum widith increase and be not less than 50mm, to meet the requirement that termination ground tackle is arranged, when the less concrete of width of beam is not easy jolt ramming, or in order to the reduction of erection time, grouting material can be adopted to pour into.
As the further scheme of the present invention: when described non-bending steel cable prestressing with bond reduces beam section height, in order to meet the requirement of beam section height, the non-bending steel cable prestressing with bond crossbeam newly established should withstand building panel and arrange, injected hole established by floor, and concrete or grouting material pour into from injected hole.
Current China there is no the renovation technique reducing beam section height, and the technology that non-bending steel cable prestressing force reduces beam section height has filled up this blank.This technology tool has the following advantages:
1, the technology of non-bending steel cable external prestressing reduction beam section height has construction simply, does not need unloading, the advantages such as do not need separately to establish temporary support, the duration is short, and expense is low, and superstructure is unaffected, and application life is synchronous with original structure; Be applicable to no more than 6 of required steel strand quantity, or more than 6 but the manageable situation of end anchorage;
2, the technology of non-bending steel cable prestressing with bond reduction beam section height has construction safety simply, does not need unloading, the advantages such as do not need separately to establish temporary support, expense is low, does not affect superstructure, and application life is synchronous with original structure; Be applicable to the situation of required steel strand quantity more than 6 and the bad process of end anchorage.
Accompanying drawing explanation
Fig. 1 is the reinforcing schematic diagram that non-bending steel cable external prestressing reduces beam section height technology;
Fig. 2 is the A-A sectional view of Fig. 1;
Fig. 3 is the B-B sectional view of Fig. 1;
Fig. 4 is the reinforcing schematic diagram that non-bending steel cable prestressing with bond reduces beam section height technology;
Fig. 5 is the C-C sectional view of Fig. 4;
Fig. 6 is the D-D sectional view of Fig. 4;
Fig. 7 is that external prestressing reduces the later sectional view of the depth of section of beam;
Fig. 8 is that prestressing with bond reduces the later sectional view of the depth of section of beam.
In figure: 1-prestress wire; 2-will reduce the beam of depth of section; 3-steel hangs rod; 4-billet; 5-ground tackle; The beam section that 6-will remove; The stirrup that 7-retains; 8-grouting material pours into; The non-prestressed positive reinforcement of 9-; The non-prestressed negative reinforcing bar of 10-; The non-prestressed handling reinforcement of 11-; 12-stirrup; The non-prestressed distributing bar of 13-; 14-connecting lacing wire; 15-injected hole; 16-1: 2 cement sand plaster.
Detailed description of the invention
Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.
Refer to Fig. 1 ~ 8, in the embodiment of the present invention, non-bending steel cable prestressing force reduces the technology of beam section height, comprises non-bending steel cable external prestressing and reduces beam section height technology and non-bending steel cable prestressing with bond reduction beam section height technology.
Non-bending steel cable external prestressing reduces beam section height technology, according to the quantity of steel strand, arranges a row or number row steel hangs rod at the belly of beam, and most next row steel hangs rod from reduction height to be not less than 50mm at the bottom of the back rest, and the distance up and down between row is not less than 30m; By tri linear shape steel strand overcoat white flame-proof PVC pipe, bottom is held steel and is hung rod; The end of steel strand adopts round buss three clip type or two clip type single hole anchor devices, and anchor is on the pillar of end or on the beam vertical with pillar, or anchor is on pin rod; The reverse bending moment produced after prestressed stretch-draw balances the moment of flexure that whole proof load produces, and then the lower section of beam is removed; After lower section is removed, retain certain length stirrup, link with electric welding after bending; At the bottom of beam, arrange template again, with grouting material perfusion, steel hangs rod and termination ground tackle C30 fine-stone concrete parcel.
Non-bending steel cable prestressing with bond reduces beam section height technology, respectively arranges a non-bending steel cable prestressing with bond crossbeam in former crossbeam both sides, and highly later with reducing depth of section beam is identical, three is unified by stirrup and connecting lacing wire.The un-bonded prestressed steel strand of parabolically shape and the nonprestressed reinforcement of linearly shape is configured in beam.Born the moment of flexure of whole standard dead load generation by prestress wire, supporting capacity insufficient section is by non-prestressed positive reinforcement and negative reinforcing bar, and the negative reinforcing bar of former crossbeam is born.
Arrange injected hole on plate top, concrete or grouting material inject from injected hole.Treat that concrete strength carries out prestressed stretch-draw after reaching designing requirement intensity.The lower section of beam removed after prestressed stretch-draw, stirrup is retained a part, after bending, welding mutually, then uses 1: 2 cement mortar to plaster closed.End anchorage wraps up with C30 fine-stone concrete after stretch-draw.
To those skilled in the art, obviously the invention is not restricted to the details of above-mentioned one exemplary embodiment, and when not deviating from spirit of the present invention or essential characteristic, the present invention can be realized in other specific forms.Therefore, no matter from which point, all should embodiment be regarded as exemplary, and be nonrestrictive, scope of the present invention is limited by claims instead of above-mentioned explanation, and all changes be therefore intended in the implication of the equivalency by dropping on claim and scope are included in the present invention.Any Reference numeral in claim should be considered as the claim involved by limiting.
Claims (8)
1. non-bending steel cable external prestressing reduces the technology of beam section height, it is characterized in that, with the non-bending steel cable in tri linear shape, bottom is held the steel being located at soffit of girder portion and is hung on rod, steel strand two ends with round buss three clip type or two clip type single hole anchor device anchors on the pillar of end, or on the reinforced concrete beam vertical with pillar, or anchor is on steel pin rod.The reverse bending moment that prestressed stretch-draw produces later, balances the moment of flexure that top proof load produces, then the lower section of beam is removed.Supporting capacity insufficient section is supplied by bearing reinforcing bar.
2. non-bending steel cable prestressing with bond reduces the technology of beam section height, it is characterized in that, respectively arrange a non-bending steel cable prestressing with bond crossbeam in former crossbeam both sides, height is identical with requiring the beam section height after reducing, and by stirrup and connecting lacing wire, three is formed entirety.Steel strand are shape parabolically, and nonprestressed reinforcement is linear.After prestressed stretch-draw, produce the moment of flexure that reverse bending moment balances the whole standard dead load generation in top, then the lower section of beam is removed.Supporting capacity insufficient section is supplied by nonprestressed reinforcement.
3. reduce the technology of beam section height according to claim 1 and non-bending steel cable prestressing force according to claim 2, it is characterized in that, non-bending steel cable adopts ultimate strength to be 1860N/mm
2u Φ
j15.2 underrelaxation non-bending steel cables, two ends ground tackle adopts round buss three clip type or two clip type single hole anchors.The stretching force of every root steel strand is not more than 180KN.
4. non-bending steel cable external prestressing according to claim 1 reduces the technology of beam section height, it is characterized in that, steel hangs rod and adopts φ 50 thick walled steel tube, interior filling C30 fine-stone concrete, is located at and reduces 50mm place at the bottom of the back rest from cross section; When there being number row steel strand, the distance up and down that steel hangs rod is not less than 30mm, and steel strand can be passed through side by side.The reverse bending moment figure that the horizontal direction position that steel hangs rod should make prestressing force produce as far as possible is consistent with the load moment of flexure figure of beam.
5. non-bending steel cable external prestressing according to claim 1 reduces the technology of beam section height, it is characterized in that, when removing the lower section of beam, the stirrup of former crossbeam is retained a part, is welded to each other after bending, then template is set, perfusion grouting material, steel strand overcoat white flame-proof PVC pipe, steel hangs rod and end anchorage C30 fine-stone concrete parcel, and the application life making beam reduce depth of section later is synchronous with original structure.
6. non-bending steel cable prestressing with bond according to claim 2 reduces the technology of beam section height, it is characterized in that, newly-installed non-bending steel cable prestressing with bond crossbeam will configure the un-bonded prestressed steel strand of parabolically shape and the non-prestressed plain bars of linearly shape simultaneously.Born the moment of flexure of whole standard dead load generation by prestress wire, by non-prestressed positive reinforcement and negative reinforcing bar, and supporting capacity supplied by the negative reinforcing bar of original crossbeam.Can avoid like this producing excessive antiarch.
7. non-bending steel cable prestressing with bond according to claim 2 reduces the technology of beam section height, and it is characterized in that, the width of newly-installed non-bending steel cable prestressing with bond crossbeam will be determined according to the layout of steel strand.When two row arranged by the side steel strand of beam, the width of this curb girder is not less than 150mm, is not less than 200mm when layout three arranges, and often increases by a row minimum widith increase and is not less than 50mm, to meet the requirement that termination ground tackle is arranged.When the less concrete of width of beam is not easy jolt ramming, or in order to the reduction of erection time, grouting material can be adopted to pour into.
8. non-bending steel cable prestressing with bond according to claim 2 reduces the technology of beam section height, it is characterized in that, in order to meet the requirement of beam section height, the non-bending steel cable prestressing with bond crossbeam of crossbeam both sides should withstand building panel and arrange, injected hole established by floor, and concrete or grouting material pour into from injected hole.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510981989.3A CN105569265A (en) | 2015-12-25 | 2015-12-25 | Technology for reduction of beam section height by use of unbonded steel strand prestress |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510981989.3A CN105569265A (en) | 2015-12-25 | 2015-12-25 | Technology for reduction of beam section height by use of unbonded steel strand prestress |
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| CN105569265A true CN105569265A (en) | 2016-05-11 |
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| CN201510981989.3A Pending CN105569265A (en) | 2015-12-25 | 2015-12-25 | Technology for reduction of beam section height by use of unbonded steel strand prestress |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106437192A (en) * | 2016-10-21 | 2017-02-22 | 江苏东南特种技术工程有限公司 | Method for carrying out reinforcing through prestress pulling cables on board |
| CN108729541A (en) * | 2018-05-29 | 2018-11-02 | 湖北沛函建设有限公司 | Connect beam type Building block construction method |
| CN113482212A (en) * | 2021-06-21 | 2021-10-08 | 五冶集团上海有限公司 | Construction method for improving structural slab surface flatness of prestressed precast beam |
| CN114737594A (en) * | 2022-05-06 | 2022-07-12 | 江苏海洋大学 | Large-span unbonded prestressed tendon's fish belly formula foundation beam |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3638371A (en) * | 1968-11-06 | 1972-02-01 | Viadimir D Liska | Precast panel building structure and method of erecting the same |
| CN104929381A (en) * | 2015-06-02 | 2015-09-23 | 项剑锋 | Steel-support non-cohesive steel strand lower support type prestress floor reinforcing method |
| CN105155868A (en) * | 2015-09-16 | 2015-12-16 | 项剑锋 | Method for pulling pillar through prestress using non-binding steel strands |
| CN105178624A (en) * | 2015-06-30 | 2015-12-23 | 项剑锋 | Prestress wall removing technology implemented by aid of non-binding steel strands |
-
2015
- 2015-12-25 CN CN201510981989.3A patent/CN105569265A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3638371A (en) * | 1968-11-06 | 1972-02-01 | Viadimir D Liska | Precast panel building structure and method of erecting the same |
| CN104929381A (en) * | 2015-06-02 | 2015-09-23 | 项剑锋 | Steel-support non-cohesive steel strand lower support type prestress floor reinforcing method |
| CN105178624A (en) * | 2015-06-30 | 2015-12-23 | 项剑锋 | Prestress wall removing technology implemented by aid of non-binding steel strands |
| CN105155868A (en) * | 2015-09-16 | 2015-12-16 | 项剑锋 | Method for pulling pillar through prestress using non-binding steel strands |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106437192A (en) * | 2016-10-21 | 2017-02-22 | 江苏东南特种技术工程有限公司 | Method for carrying out reinforcing through prestress pulling cables on board |
| CN106437192B (en) * | 2016-10-21 | 2018-10-16 | 江苏东南特种技术工程有限公司 | A method of it is reinforced using prestressed cable in plate face |
| CN108729541A (en) * | 2018-05-29 | 2018-11-02 | 湖北沛函建设有限公司 | Connect beam type Building block construction method |
| CN113482212A (en) * | 2021-06-21 | 2021-10-08 | 五冶集团上海有限公司 | Construction method for improving structural slab surface flatness of prestressed precast beam |
| CN114737594A (en) * | 2022-05-06 | 2022-07-12 | 江苏海洋大学 | Large-span unbonded prestressed tendon's fish belly formula foundation beam |
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