CN103147537B - A kind of bending carrying girder steel - Google Patents

Abstract

The invention belongs to material structure research field, be specifically related to a kind of novel bearing girder steel combined by girder steel and prestress rope.The bending carrying girder steel of the present invention, the tensile region of girder steel is that two ends are fixed on the steel wire at web two ends by steel wire pre-tightening apparatus, and steel wire is in steel deflection of beam neutral surface.The tensile region of girder steel is used instead steel wire and is replaced by the present invention.Before structure bears external load, in advance the steel wire under its outer load effect is applied according to actual condition compressive stress, or the quantity of increase steel wire, to improve the mechanical property of girder steel, and plays the purpose of loss of weight.

Description

A kind of bending carrying girder steel

Technical field

The invention belongs to material structure research field, be specifically related to a kind of novel bearing girder steel combined by girder steel and prestress rope.

Background technology

The target that lightweight, the high-strength structural engineer of being pursue for a long time.Lightweight, high-strength material of can saving undoubtedly, increase usable floor area, and reduction foundation load is returned construction and brought convenience.Reduce building materials consumption, certainly can facilitate energy-conservation, resource-saving, minimizing garbage and greenhouse gas emissions.Develop building materials high-strength, lightweight particularly significant.Building industry steel accounts for 53%, and the weight effectively reducing steel has highly important meaning to industries such as buildings.

Along with external lightweight steel construction slowly enters into Chinese market, people's huge change to the noegenesis of lightweight steel construction, its application is wider, gradually by work with to civilian house show.The feature of steel construction self be exactly lightweight, intensity is high, simple in construction.Such as I-steel, belonging to high-efficiency and economic and cut out face section bar, owing to cross sectional shape is reasonable, they can make steel higher play usefulness, improves and holds sanction ability.Steel I-beam has been widely used for the fields such as building, bridge；T-steel is the ideal material substituting double angle welding.Have that bending resistance is strong, it is simple, cost-effective to construct and the advantage such as lightweight construction.It is mainly used in machinery, fills the use of hardware shaped steel；U-shaped steel, it is stressed greatly, and supporting time is long, easily installs features such as being unlikely to deform.The purposes such as the support supporting being mainly used in mine laneway, mine laneway secondary supporting and mountain tunnel.

Steel wire rope is one of most widely used heavy material, has bearing capacity big, and intensity is high, the advantage of light weight.It it is preferable tensile materials.Compressor wire be use carbon steel wire rod process, be applied to prestressed reinforced concrete construction or a kind of steel wire of prestressed steel structure, the high intensity of this material is mainly manifested in axis direction, the most considerably lower.The cross section that the most same material is same, steel wire rope more can bear pulling force.

Before Engineering Structure Component bears external load, to the reinforcing bar in tension module or steel wire, apply compressive pre-stress, the rigidity of component can be improved, postpone the time that crack occurs, increase the durability of component.From the point of view of frame for movement, its implication is for make it produce stress in advance, and its benefit is to improve the rigidity of structure own, and minimizing vibration and elastic deformation do so can be obviously improved the elastic strength of tension module, makes resistance originally higher.

Summary of the invention

It is an object of the invention to provide a kind of reduction weight when reaching with tradition girder steel same bearer ability, reduce the novel bearing girder steel of cost.

The object of the present invention is achieved like this:

The bending carrying girder steel of the present invention, the tensile region of girder steel is that two ends are fixed on the steel wire at web two ends by steel wire pre-tightening apparatus, and steel wire is in steel deflection of beam neutral surface.

Girder steel is I-steel, and the quantity of steel wire used need to meet

${\mathrm{nF}}_{\max }^{\′}\≥F_{\max },n(h-t_2)F_{\max }^{\′}\≥M_{\max },$

Wherein n is the quantity of steel wire used,For the Ultimate Tensile power of steel wire rope, F_maxThe limit suffered by bending neutral surface the latter half is made a concerted effort, M_maxFor the limit resultant moment suffered by bending neutral surface the latter half, h is I-steel neutral surface position height.

Girder steel is T-steel, and the position of bending neutral surface is

$h_T=\frac{S_1\frac{h_1}{2}+S_2(h+\frac{t_1}{2})}{S_1+S_2}=\frac{S_1{h}_1+S_2(2h+t_1)}{2(S_1+S_2)},$

Wherein h₁For web height, t₁For web thickness, t₂For edge of a wing thickness, S₁Amass for web plate section, S₂Amass for flange section；On web, quantity and the position of steel wire used need to meet claimed below

${\mathrm{nF}}_{\max }^{\′}\≥F_{\max },\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i{F}_{\max }^{\′}\≥M_{\max },$

Wherein n is the quantity of steel wire used, y_iIt is the height coordinate of i-th steel wire rope,For the Ultimate Tensile power of steel wire rope, F_maxThe limit suffered by bending neutral surface the latter half is made a concerted effort, M_maxFor the limit resultant moment suffered by bending neutral surface the latter half.

Girder steel is that the position of U-shaped steel bending neutral surface is

$h_U=\frac{S_1\frac{h_1}{2}{S}_1\frac{h_1}{2}+S_2(h+\frac{t_1}{2})}{S_1+S_1+S_2}=\frac{{2S}_1{h}_1+S_2(2h+t_1)}{4S_1+2S_2},$

Wherein h₁For web height, t₁For web thickness, t₂For edge of a wing thickness, S₁Amass for web plate section, S₂Amass for flange section；On web, quantity and the position of steel wire used need to meet claimed below

${\mathrm{nF}}_{\max }^{\′}\≥F_{\max },\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i{F}_{\max }^{\′}\≥M_{\max },$

Wherein n is the quantity of steel wire used, y_iIt is the height coordinate of i-th steel wire rope,For the Ultimate Tensile power of steel wire rope, F_maxThe limit suffered by bending neutral surface the latter half is made a concerted effort, M_maxFor the limit resultant moment suffered by bending neutral surface the latter half.

The beneficial effects of the present invention is:

The tensile region of girder steel is used instead steel wire and is replaced by the present invention.Before structure bears external load, in advance the steel wire under its outer load effect is applied according to actual condition compressive stress, or the quantity of increase steel wire, to improve the mechanical property of girder steel, and plays the purpose of loss of weight.

Accompanying drawing explanation

Fig. 1 is the steel I-beam improved；

Fig. 2 is the T-steel beam improved；

Fig. 3 is the U-shaped girder steel improved；

Fig. 4 is the T-steel beam section figure improved；

Fig. 5 is the U-shaped girder steel sectional view improved；

Fig. 6 is the steel I-beam sectional view improved.

Detailed description of the invention

The present invention is further illustrated below in conjunction with the accompanying drawings.

The present invention relates to a kind of novel bearing material structure combined by girder steel and prestress rope.Its design is a kind of and tradition girder steel is when reaching same bearer ability, plays reduction weight, reduces the purpose novel bearing girder steel of cost, as shown in Figure 1, 2, 3.

The present invention is realized in.As a example by I-steel, material structure figure is shown in Fig. 1.In Fig. 1, each numbering specific name is as follows: 1 flange plate；2 webs；3 compressor wires；4 steel wire pre-tightening apparatus；5 steel wires are connected with girder steel.When bending due to steel I-beam carrying, upper strata flange plate compression chord, lower floor's flange plate tension stress.Because beam to bear certain shear stress when carrying, suitable for the tensile region of steel I-beam is removed, in order to do not affect the shear resistance of girder steel after improvement.And change the edge being connected web with upper strata flange plate into arch, to avoid stress to concentrate.Can use punching, add the methods such as pin, in web arch edge, connect both sides with steel wire, and with steel wire pre-tightening apparatus, steel wire is applied compressive stress.Make when girder steel carries, flange plate above to bear compressive stress, by following bearing steel wires tension stress.Because beam to bear certain shear stress when carrying, calculate the shear stress that girder steel is to be born, when cutting out the compressive region removing girder steel, be in the range of girder steel shearing resistance is permitted.If the girder steel after Gai Jining can not meet the shear resistance of industrial and mineral, can suitably thicken the thickness of upper strata flange plate, in order to do not affect the shear resistance of girder steel after improvement.Owing to steel wire has more preferable resistance to tension, and lighter weight.The novel beam being made up of girder steel and steel wire can use as lightweighting materials.

T-steel beam, U-shaped girder steel improved method just as, the tensile region of kind of girder steel when bending, is used instead steel wire and is replaced by the carrying of T-steel, U-shaped girder steel.Before structure bears external load, in advance the steel wire under its outer load effect is applied according to actual condition compressive stress, or the quantity of increase steel wire, to improve the mechanical property of girder steel, and plays the purpose of loss of weight.

As it is shown in figure 1, a kind of novel bearing girder steel.During girder steel carrying upper strata flange plate [1], bearing compressive stress, girder steel is the main member of shearing stress when carrying；Web [2], is primarily subjected to tension.Cut out when going to the compressive region of girder steel, meet in the range of shear resistance permitted at girder steel.Requirement according to carrying adjusts the height of web, and the tension of carrying is the biggest, can increase the height of web；Compressor wire [3], the main member of carrying tension, according to the size of carrying, different with the position of steel wire, adjust the size that steel wire is prestressed.The tension being subject to due to the bearing steel wires that position is the most downward is bigger, can be selected for thicker steel wire and sets bigger prestressing force.And the quantity of steel wire is increased according to practical situation；Steel wire pre-tightening apparatus [4], during Wire pulling, adjusts steel wire prestressing force, regulates the prestressed size of steel wire according to actual condition；Steel wire is connected [5] with girder steel, is wound around according to the optional punching of practical situation, or adds the prescriptive procedures such as pin, and fixation with steel wire is on girder steel.

Its operation principle is: when traditional girder steel carries, due to flecition, lower floor's flange plate is primarily subjected to tension.Bearing steel wires tension stress then used instead by novel carrying girder steel.Weight is reduced while ensureing bearing capacity.In order to preferably replace tradition girder steel, first find the neutral surface of steel deflection of beam, removed the height of part just for the height of neutral surface.Owing to the cross section of steel I-beam is symmetrical, so its bending neutral surface is in centre.And for tee girder and U-shaped Liangqi neutral surface in its centre of form, its size is as shown in Figure 4, Figure 5.The position judgment formula of its bending neutral surface is respectively as follows:

$h_T=\frac{S_1\frac{h_1}{2}+S_2(h+\frac{t_1}{2})}{S_1+S_2}=\frac{S_1{h}_1+S_2(2h+t_1)}{2(S_1+S_2)}$

$h_U=\frac{S_1\frac{h_1}{2}{S}_1\frac{h_1}{2}+S_2(h+\frac{t_1}{2})}{S_1+S_1+S_2}=\frac{{2S}_1{h}_1+S_2(2h+t_1)}{4S_1+2S_2}$

Wherein h₁For web height, t₁For web thickness, t₂For edge of a wing thickness, S₁Amass for web plate section, S₂Amass for flange section.

In order to realize equivalence replacement, the quantity of steel wire of institute's energy, diameter, prestressing force, position all there are certain requirements.For traditional T-shaped beam and U-shaped beam, its limit suffered by neutral surface the latter half is made a concerted effort and limit resultant moment is respectively

$F_{\max }=t_1{\∫}_0^{h_T}\frac{\left[\mathrm{\σ}\right]s}{h_T}\mathrm{ds}=\frac{t_1{h}_T}{2}\left[\mathrm{\σ}\right],M_{\max }=t_1{\∫}_0^{h_T}\frac{\left[\mathrm{\σ}\right]s}{h_T}\mathrm{sds}=\frac{t_1{h}_T^2}{3}\left[\mathrm{\σ}\right]$

$F_{\max }=t_1{\∫}_0^{h_U}\frac{\left[\mathrm{\σ}\right]s}{h_U}\mathrm{ds}=\frac{t_1{h}_U}{2}\left[\mathrm{\σ}\right],M_{\max }=t_1{\∫}_0^{h_U}\frac{\left[\mathrm{\σ}\right]s}{h_U}\mathrm{sds}=\frac{t_1{h}_U^2}{3}\left[\mathrm{\σ}\right]$

Wherein [σ] is the need stress of steel used by girder steel.The diameter D=0.6t of regulation steel wire rope₂.Then the Ultimate Tensile power of steel wire rope is

$F_{\max }^{\′}=\frac{{\mathrm{\πD}}^2}{4}\left[{\mathrm{\σ}}^{\′}\right]$

Wherein [σ '] is the need stress of steel wire rope.

For reaching intensity equivalence, then quantity and the position of steel wire used need to meet claimed below for T-shaped beam and U-shaped beam on each web

${\mathrm{nF}}_{\max }^{\′}\≥F_{\max },\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i{F}_{\max }^{\′}\≥M_{\max },$

Wherein n is the quantity of steel wire used, y_iIt it is the height coordinate of i-th steel wire rope.

For I-steel, its size is as shown in Figure 6

$F_{\max }=t_2{\∫}_0^{h-t_2}\frac{\left[\mathrm{\σ}\right]s}{h}\mathrm{ds}+l{\∫}_{h-t_2}^h\frac{\left[\mathrm{\σ}\right]s}{h}\mathrm{ds}=\frac{t_2\left[\mathrm{\σ}\right]{(h-t_2)}^2}{2h}+\frac{l\left[\mathrm{\σ}\right](2{\mathrm{ht}}_2-t_2^2)}{2h}$

$F_{\max }=t_2{\∫}_0^{h-t_2}\frac{\left[\mathrm{\σ}\right]s}{h}\mathrm{sds}+l{\∫}_{h-t_2}^h\frac{\left[\mathrm{\σ}\right]s}{h}\mathrm{sds}=\frac{t_2\left[\mathrm{\σ}\right]{(h-t_2)}^3}{3h}+\frac{l\left[\mathrm{\σ}\right][h^3-{(h-t_2)}^3]}{3h}$

For Novel I-shaped steel beam, steel wire is mainly fixed on lower floor's flange plate, and symmetrical.The quantity of steel wire used need to meet claimed below

$n{F}_{\max }^{\′}\≥F_{\max },n(h-t_2)F_{\max }^{\′}\≥M_{\max }$

In order to increase the stability of Novel I-shaped steel beam, web adds a steel wire again.

For the pretightning force of steel wire, should be with depending on according to concrete operating mode, carrying the biggest, the pretightning force of steel wire is the biggest.

Claims (1)

1. a bending carrying girder steel, it is characterized in that: suitable the removing in tensile region of girder steel, and change web edge into arch, steel wire is fixed on web two ends or web and two ends, lower flange Shi Hanzhang by steel wire pre-tightening apparatus so that girder steel tensile region is used steel wire instead and replaced, and girder steel is I-steel, T-steel or U-shaped steel；

When described girder steel is I-steel, the quantity of steel wire used need to meet

nF′_max≥F_max, n (h-t₂)F′_max≥M_max,

Wherein n is the quantity of steel wire used, F '_maxFor the Ultimate Tensile power of steel wire rope, F_maxThe limit suffered by bending neutral surface the latter half is made a concerted effort, M_maxFor the limit resultant moment suffered by bending neutral surface the latter half, h is I-steel neutral surface position height, t₂For I-steel lower flange thickness；

When described girder steel is T-steel, the position of bending neutral surface is

$h_T=\frac{S_1\frac{h_1}{2}+S_2(h+\frac{t_1}{2})}{S_1+S_2}=\frac{S_1{h}_1+S_2(2h+t_1)}{2(S_1+S_2)},$

$F_{max}=t_1{\∫}_0^{h_T}\frac{\[\mathrm{\σ}\]s}{h_T}ds=\frac{t_1{h}_T}{2}\[\mathrm{\σ}\],M_{max}=t_1{\∫}_0^{h_T}\frac{\[\mathrm{\σ}\]s}{h_T}sds=\frac{t_1{h}_T^2}{3}\[\mathrm{\σ}\]$

Wherein h₁For web height, t₁For web thickness, t₂For edge of a wing thickness, S₁Amass for web plate section, S₂Amass for flange section；On web, quantity and the position of steel wire used need to meet claimed below

${\mathrm{nF}}_{max}^{\′}\≥F_{max},\underset{i=1}{\overset{n}{\Σ}}{y}_i{F}_{max}^{\′}\≥M_{max},$

Wherein n is the quantity of steel wire used, y_iIt is the height coordinate of i-th steel wire rope, F '_maxFor the Ultimate Tensile power of steel wire rope, F_maxThe limit suffered by bending neutral surface the latter half is made a concerted effort, M_maxFor the limit resultant moment suffered by bending neutral surface the latter half；When described girder steel is U-shaped steel, the position of bending neutral surface is

$h_U=\frac{S_1\frac{h_1}{2}+S_1\frac{h_1}{2}+S_2(h+\frac{t_1}{2})}{S_1+S_1+S_2}=\frac{2S_1{h}_1+S_2(2h+t_1)}{4S_1+2S_2},$

$F_{max}=t_2{\∫}_0^{h-t_2}\frac{\[\mathrm{\σ}\]s}{h}sds+l{\∫}_{h-t_2}^h\frac{\[\mathrm{\σ}\]s}{h}sds=\frac{t_2\[\mathrm{\σ}\]{(h-t_2)}^3}{3h}+\frac{l\[\mathrm{\σ}\]\[h^3-{(h-t_2)}^3\]}{3h}$

Wherein h₁For web height, t₁For web thickness, t₂For edge of a wing thickness, S₁Amass for web plate section, S₂Amass for flange section；On web, quantity and the position of steel wire used need to meet claimed below

${\mathrm{nF}}_{max}^{\′}\≥F_{max},\underset{i=1}{\overset{n}{\Σ}}{y}_i{F}_{max}^{\′}\≥M_{max},$

Wherein n is the quantity of steel wire used, y_iIt is the height coordinate of i-th steel wire rope, F '_maxFor the Ultimate Tensile power of steel wire rope, F_maxThe limit suffered by bending neutral surface the latter half is made a concerted effort, M_maxFor the limit resultant moment suffered by bending neutral surface the latter half；A diameter of D of regulation steel wire rope, then the Ultimate Tensile power of steel wire rope is

$F_{max}^{\′}=\frac{{\mathrm{\πD}}^2}{4}\[{\mathrm{\σ}}^{\′}\]$

Wherein [σ '] is the need stress of steel wire rope.