CN102296751B

CN102296751B - Prestressing anti-fatigue girder

Info

Publication number: CN102296751B
Application number: CN 201110145481
Authority: CN
Inventors: 马人乐
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-06-01
Filing date: 2011-06-01
Publication date: 2013-03-20
Anticipated expiration: 2031-06-01
Also published as: CN102296751A

Abstract

The invention belongs to the technical field of civil engineering, and specifically relates to a prestressing anti-fatigue girder. The prestressing anti-fatigue girder comprises a top flange, a bottom flange, a web, a bearer stiffening plate and prestressing anchor slab, anchor holes, a high-strength prestressing steel strand, an anchoring stiffening plate, an anchor head, an arc plate, a bearer steel bracket and lateral movement proof cushion block. The prestressing steel strand is penetrated into anchor holes which are near to a tensile flange and are symmetrical on two sides of the web, and is anchored by the anchor head after stretch-draw, so as to generate a precompression on a girder tensile area. After prestressing relaxation, the prestressing steel strand has a pressure stress larger than amplitude of a self-weight stress and a fatigue tensile stress; and the girder bottom flange will not be subjected to tension under compound effects of deadweight and fatigue load. Therefore, a fatigue problem id solved. According to the invention, a design fatigue stress amplitude of the bottom flange is increased from a former one limited in an allowed fatigue stress amplitude to one approaching a design strength f, so as o substantially increase anti-fatigue capability and change a fatigue brittle failure to a ductility strength problem. An ultimate strength of the bottom flange is increased by one time, so as to substantially increase material utilization rate of high-strength steel.

Description

The prestressing force anti-fatigue girder

Technical field

The invention belongs to technical field of civil engineering, be specifically related to a kind of prestressing force anti-fatigue girder.

Background technology

The permission Fatigue Stress Amplitude of anti-fatigue girder (such as heavy duty crane beam, driving girder, bridge etc.) is all lower at present, and high strength steel aspect antifatigue without any advantage, allow Fatigue Stress Amplitude and intensity ratio to be significantly less than the ratio of fatigue effect and volume effects.For main anti-fatigue girder, except connecting, Q235 steel, 2 classes can bring into play simultaneously the strength of materials and the anti-fatigue ability, and material is controlled by antifatigue in all the other situations, and strength of materials utilization rate is not enough.The strength of materials is higher, the connection classification is poorer, the fatigue loading number of repetition is more, and then strength of materials utilization rate is lower.In addition, structural fatigue destroys and is brittle fracture at present, and incident is unexpected, can cause major accident.For this reason, require to have a kind of method to make fatigue problem not become the controlled factor that the restriction Materials with High Strength is used, avoid high-strength girder steel generation brittle failure to destroy, thereby take full advantage of the strength of materials, saving steel, the safety that improves structure under the fatigue effect.

Summary of the invention

The object of the present invention is to provide a kind of prestressing force anti-fatigue girder.

The prestressing force anti-fatigue girder that the present invention proposes, formed by top flange 1, bottom flange 2, web 3, anchor slab 4, anchor hole 5, high-strength prestress steel strand 6, anchoring stiffening plate 7, anchor head 8, arc 9 and bearing steel corbel 10, top flange 1, web 3 and bottom flange 2 are welded to form the H section steel beam successively, described H section steel beam two ends are fixed on the bearing steel corbel 10, web 3 both sides that are positioned at bearing steel corbel 10 tops are welded with anchor slab 4, and described anchor slab 4 plays the girder steel bearing stiffener prestressing force anchor slab of holding concurrently; The anchor slab 4 that is positioned at H section steel beam two ends is respectively equipped with anchor hole 5 near 2 places, bottom flange about the both sides of web 3 symmetries, anchor hole 5 all is welded with up and down anchorage zone stiffener 7, anchor slab 4 is provided with an arc 9 to H section steel beam one end distolateral, projection is pressed on the anchor slab 4 corresponding with web 3 center lines in the middle of the arc 9, prestress wire 6 one ends pass the anchor hole 5 on

arc

9,2 anchor slabs 4 successively, after the stretch-draw, prestress wire 6 two ends are by anchor head 8 anchorings.

Among the present invention, described prestress wire 6 radicals are 2, apply that the tensile region by

anchor head

8 and 4 pairs of girder steel bottom flanges 2 of anchor slab and web 3 produces compressive stress behind the pretension.

Among the present invention, girder steel and steel strand are all used high strength steel.

Among the present invention, prestress wire 6 has an end to be fixed on the arc 9, so if just in case side steel strand are disrumpent feelings, opposite side steel strand simultaneously pulling force disappear, and can not produce the side direction moment of flexure to beam.

Among the present invention, the H section steel beam is made first prestressed stretch-draw and is installed on the bearing steel corbel 10 again.

Among the present invention, closely accompany anti-sidesway cushion block 11 between web 3 middle parts and prestress wire 6 middle parts, when the web of H section steel beam had sidesway trend, prestress wire namely applied reverse restoring force to web, to keep the lateral stability of lower flange of girder edge 2.

The principle of the invention is as follows: with high strength steel strand girder steel bottom flange and the larger zone of adjacent web tension stress are applied precompression.Compressive stress adds tired tensile stress amplitude greater than the lower tensile stress of deadweight after making it consider Relaxation of prestressing.Then the bottom flange of beam can not enter tension yet under deadweight and fatigue loading compound action, thereby has solved fatigue problem.

Advantage of the present invention is:

Bottom flange design Fatigue Stress Amplitude is confined to allow Fatigue Stress Amplitude can bring up near design strength f from former, and anti-fatigue ability significantly improves.

The brittle fracture of fatigue is become strength problem, and (this kind situation is general first by a side steel strand generation fatigue rupture, and the effect opposite side steel strand owing to the arc cushion block after side steel strand are disrumpent feelings also lose pretension to be ductility.Girder steel becomes without the common girder steel of prestressing force.But girder steel is through designing the Static behavior of resisting fatigue characteristic value of load own.So can not causing structure, the steel strand fatigue failure do not decay, so as long as brittle fracture has been avoided in maintenance).

Steel strand and anti-sidesway cushion block interact can improve the beam lateral stability.

Significantly improve the stock utilization of high strength steel.

Description of drawings

Fig. 1 is the elevation of prestressing force anti-fatigue girder.

Fig. 2 is the A-A sectional drawing of Fig. 1.

Fig. 3 is the B-B sectional drawing of Fig. 1.

Fig. 4 is the C-C sectional drawing of Fig. 1.

Fig. 5 is the D-D sectional drawing of Fig. 1.

Fig. 6 is the cross-sectional view of prestressing force antifatigue steel beam with box shape.

Number in the figure: 1 is the top flange, and 2 is the bottom flange, and 3 is web, and 4 is anchor slab, and 5 is anchor hole, and 6 is the prestressed high strength steel strand, and 7 is anchoring stiffening plate, and 8 is anchor head, and 9 is arc, and 10 is the bearing steel corbel, and 11 are anti-sidesway cushion block.

The specific embodiment

The invention will be further described below in conjunction with accompanying drawing and example.

Embodiment 1: such as Fig. 1-shown in Figure 6, this device is comprised of hold concurrently prestressing force anchor slab 4, anchor hole 5, high-strength prestress steel strand 6, anchoring stiffening plate 7, anchor head 8, arc 9, bearing steel corbel 10 and anti-sidesway cushion block 11 of top flange 1, bottom flange 2, web 3, bearing stiffener.Top flange 1, bottom flange 2 and web 3 form the welded H section steel beam.H section steel beam two ends are fixed on the bearing steel corbel 10, are welded with anchor slab 4 corresponding to web 3 both sides of bearing steel corbel 10 tops.This anchor slab 4 is both as the girder steel bearing stiffener also double prestressing force anchor slab of doing.H section steel beam one end (right-hand member) is located respectively to be provided with anchor hole 5 about the both sides of web 3 symmetries near the bottom flange at anchor slab 4, and anchor hole 5 is welded with up and down anchorage zone stiffener 7.The beam other end (left end) is drilled with anchor hole 5 equally at anchor slab 4 and right-hand member opposite position, and anchor slab is established an arc 9 to the beam-ends side, and arc 9 also is drilled with same anchor hole.Projection is pressed on the anchor slab 4 corresponding with web 3 center lines in the middle of the arc 9.Penetrate prestress wire 6 in the anchor hole 5 about web 3 symmetries, use anchor head 8 anchorings after the stretch-draw.Prestress wire 6 applies that the tensile region by

anchor head

8 and 4 pairs of girder steel bottom flanges 2 of anchor slab and web 3 produces compressive stress behind the pretension.Girder steel and prestress wire 6 are all used high strength steel.Prestress wire 6 has an end to be fixed on the arc 9, so if just in case side steel strand are disrumpent feelings, opposite side steel strand simultaneously pulling force disappear, and can not produce the side direction moment of flexure to beam.Anti-sidesway cushion block 11 closely is clipped in web 3 and prestress wire 6 central authorities, and when the web of beam had sidesway trend, steel strand namely applied reverse restoring force to web, to keep the lateral stability of lower flange of girder edge 2.

Said apparatus is used for heavy-duty worker shaped steel crane girder, calculates bottom flange 2 because of the tensile stress sigma of conducting oneself with dignity and the fatigue loading standard value causes _p, in web 3 both sides near bottom flange 2 prestress wire 6 is set, and it is applied pretension.After the deduction loss of prestress, 2 compressive stress that produce equal σ to pretension in the bottom flange _p, girder steel tension not under fatigue effect then, antifatigue satisfies naturally.

Embodiment 2: embodiment 1 described device is used for the traversing crane steel beam with box shape, and near web 3 both sides the traversing crane steel beam with box shape tension edge of a wing arrange prestress wire 6, and it is applied pretension.Similarly, after the deduction loss of prestress, pretension produces compressive stress on the tension edge of a wing.Girder steel tension not under fatigue effect, antifatigue satisfies.Because having adopted high-strength material, and improve stock utilization, so case beam weight can significantly reduce, be conducive to the reduction of the long-term energy consumption of traversing crane.

Claims

1. prestressing force anti-fatigue girder, comprise top flange (1), bottom flange (2), web (3), anchor slab (4), anchor hole (5), prestress wire (6), anchorage zone stiffener (7), anchor head (8), arc (9) and bearing steel corbel (10), it is characterized in that top flange (1), web (3) and bottom flange (2) are welded to form the H section steel beam successively, described H section steel beam two ends are fixed on the bearing steel corbel (10), web (3) both sides that are positioned at bearing steel corbel (10) top are welded with anchor slab (4), and described anchor slab (4) plays the girder steel bearing stiffener prestressing force anchor slab of holding concurrently; The anchor slab (4) that is positioned at H section steel beam two ends is located to be respectively equipped with anchor hole (5) about the symmetrical both sides of web (3) near bottom flange (2), anchor hole (5) all is welded with up and down anchorage zone stiffener (7), anchor slab (4) is towards the distolateral arc (9) that is provided with of H section steel beam one end, projection is pressed on the anchor slab (4) corresponding with web (3) center line in the middle of the arc (9), prestress wire (6) one ends pass arc (9) successively, anchor hole (5) on 2 anchor slabs (4), after the stretch-draw, prestress wire (6) two ends are by anchor head (8) anchoring.

2. prestressing force anti-fatigue girder according to claim 1 is characterized in that described prestress wire (6) radical is 2.

3. prestressing force anti-fatigue girder according to claim 1 is characterized in that closely accompanying anti-sidesway cushion block (11) between web (3) middle part and prestress wire (6) middle part.