CN104514202A - Single-column pier beam bridge anti-overturning reinforcing method - Google Patents

Abstract

The invention discloses a single-column pier beam bridge anti-overturning reinforcing method which includes the steps: (1) determining an anti-overturning side and an overturning side according to preset load conditions and setting an overturning load target value; (2) building a torque state equation of a critical overturning state according to the overturning load target value; (3) adjusting the sizes of bearings of a single-column pier beam bridge or adjusting the distance between anti-torsional bearings according to the torque state equation to reinforce the single-column pier beam bridge. The single-column pier beam bridge anti-overturning reinforcing method is simple and easy to implement, the single-column pier beam bridge can be reinforced by changing the sizes of the bearings, and the anti-overturning capacity of the single-column pier beam bridge is improved.

Description

A kind of Single column pier beam bridge overturning or slip resistance analysis reinforcement means

Technical field

The present invention relates to civil engineering technology, be specifically related to a kind of Single column pier beam bridge overturning or slip resistance analysis reinforcement means.

Background technology

The reason of bridge collapse accident comprises construction quality deficiency, it is unreasonable to design, overload of vehicle, shock and other collapsing of being caused by natural conditions.Particularly in succession the collapsing of Single column pier beam bridge in recent years, causes social extensive concern.

At present, domestic bridge design personnel compare attention to the bending resistance of superstructure, shear-carrying capacity and crack-resistant performance of concrete, when meeting code requirement, have larger redundancy.But with toppling to collapse, necessary attention is lacked to the lateral stability of bridge, even if consider overturn stability, also mostly whether end bearing being come to nothing as evaluating the sole indicator that topples of bridge, the impact of superstructure deadweight on overturning or slip resistance analysis cannot be considered, just bury potential safety hazard in the design stage.Single column pier beam bridge is to be subject to curved girder as the bridge of supporting member, and primarily of superstructure and substructure composition, its superstructure mainly comprises box type girder (i.e. case beam), bearing, deck paving, drainage system, guard rail; Substructure mainly comprises abutment, bridge pier, basis.Single column pier beam bridge two ends adopt twin shaft pier (comprising two bridge piers side by side), and twin shaft pier each pier is provided with an anti-torsional bearing, and middle employing Single column pier, each pier is provided with a bearing.Two anti-torsional bearing in usual title twin shaft pier are same as anti-torsional bearing.

For increasing the resistance to capsizing of Single column pier beam bridge, can insert twin shaft pier at Single column pier interval, namely except head and the tail two ends, mid portion is also distributed with twin shaft pier.

In the standard of highway bridge that China is existing, not yet clear stipulaties is made to bridge construction overturning stability.In " highway bridge and culvert design general specification " (JTGD60-2004), 3.5.8 bar and " highway reinforced concrete and prestressed concrete bridge contain design specifications " (JTGD62-2004) middle 9.7.4 bar all only forbid the description that bridge pad comes to nothing.Under in the Ministry of Railways " railway bridges and culverts reinforced concrete and prestressed concrete structure design specifications " (TB10002.3-2005), 4.1.1 bar is defined in the most dangerous combination effect calculating load, the horizontal safety factor on toppling stability of bridge span structure should not be less than 1.3.Although and existing urban bridge design specification proposes the requirement ensureing integral bridge stability, do not provide clear and definite Method for Checking and respective standard.Transportation department of Zhejiang Province proposes in " about only columnar pier bridge stability sex chromosome mosaicism informal discussion meeting summary ", in Practical Calculation is analyzed except definition 1.3 times of lane loads, by bearing, whether further definition 1.2 times of vehicular loads, as the check load that topples, occur that negative reaction judges the overturning or slip resistance analysis performance of bridge construction.In railroad bridge, overload still not serious; But in highway bridge, along with the fast development of equipment manufacture, overload of vehicle 2-3 is doubly comparatively common.According to Reliability Theory, by partial safety factor to strength of materials reduction and to external load amplification, the actual bending resistance of structure or shear-carrying capacity can reach the 3-4 of design load doubly.Therefore, in the design of highway bridge, calculate superstructure overturn stability and only consider that overload 30% cannot adapt to the actual conditions of existing vehicle load; Structure is toppled and is only adopted bearing whether to occur negative reaction to judge also being worth discussion simultaneously; Finally, owing to lacking effective practical calculation method, engineering staff science cannot judge whether bridge topples fast.

Summary of the invention

For the deficiencies in the prior art, the invention provides a kind of Single column pier beam bridge overturning or slip resistance analysis reinforcement means.Comprise the steps:

(1) for the load situation determination overturning or slip resistance analysis side of presetting and side of toppling, the load desired value and setting is toppled;

(2) the moment state equation of critical condition of toppling is built according to described load desired value of toppling;

(3) regulate distance between the size of the bearing of Single column pier beam bridge or anti-torsional bearing to reinforce Single column pier beam bridge according to described moment state equation.The reinforcement means of Single column pier beam bridge of the present invention is simple, be easy to realize, and just completing reinforcing, improving the resistance to capsizing of Single column pier beam bridge by changing supporting stand size.

Regulate in the present invention the distance between anti-torsional bearing refer in particular to regulate same as the distance in anti-torsional bearing between two anti-torsional bearing.

For ensureing that Single column pier beam bridge does not topple, improve safety, the load of side of toppling under described load desired value of toppling is greater than default load situation, 1.3 ~ 2 times of the side load that topples under being generally default load situation.

During critical condition of toppling, the pivot center of the case beam of Single column pier beam bridge and the distance of bearing proximal edge (edge of nearest side, position) equal the thickness of bearing.

When in the present invention, Single column pier beam bridge reaches seat empty state, for round bearing, pivot center is positioned at from 1/4R place, bearing center, wherein R is the radius of bearing, pivot center for rectangle bearing (horizontal section is rectangle) is positioned at from 1/6B place, bearing center, and B is the wide of rectangle.

Carload produces vertical load and moment of torsion to beam bridge under uneven loading action:

When the stabilization sub stage, bridge pier counter-force is combined by two side ends bearing (anti-torsional bearing) and middle Single column pier to be provided; In use due to the load effect of case beam both sides, the pivot center of case beam departs from the geometric center of bearing gradually, and when side-play amount reaches certain degree, phenomenon of coming to nothing appears in overturning or slip resistance analysis side anti-torsional bearing, enters transitional stage.

When transitional stage, due to before critical condition, the bearing of overturning or slip resistance analysis side has been in seat empty state at (comprising the anti-torsional bearing of this side), and therefore the bearing of this side can not produce the moment of overturning or slip resistance analysis;

When toppling the stage, pivot center reaches capacity position, now the bearing of overturning or slip resistance analysis side comes to nothing, the overturning moment that lateral deviation of toppling carries generation equals superstructure (i.e. case beam) dead-load moment, overturning or slip resistance analysis side load moment and side anti-torsional bearing counter-force moment three sum of toppling, and the load of opposing vertical (i.e. vertical direction) combined by topple side anti-torsional bearing and middle Single column pier bearing.

In the present invention using topple moment as critical condition of toppling, using this critical condition Single column pier beam bridge overturning moment as Single column pier beam bridge overturning or slip resistance analysis carry moment.Method of the present invention, when practical application, first determines side of toppling, then using opposite side as overturning or slip resistance analysis side.

When Single column pier beam bridge reaches overturn stability critical condition, its pivot center is positioned at bearing feather edge 45 ° upwards toward diffusion position inside bearing.When bearing shape is different, under critical condition, the position of pivot center is also different.

When the bearing cross section of Single column pier beam bridge is circular, described pivot center equals the thickness of bearing to the distance at bearing (intermediate support, non-anti-torsional bearing) edge.When the bearing cross section of Single column pier beam bridge is rectangle, described pivot center equals the thickness of bearing to the distance at bearing (intermediate support, non-anti-torsional bearing) edge.

The moment state equation of described critical condition of toppling is as follows:

L _R＝L _O，

Wherein, L _rresistance to tipping moment under critical condition of toppling:

L _ofor overturning moment desired value, according to toppling, load desired value calculates.

Overturning moment L under described critical condition of toppling _raccording to formula:

$L_R=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{P}_A^i\×l_A^i+\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{P}_B^j\×l_B^j+q_G\×l_0\×l_q,$

Calculate, wherein, for i-th, overturning or slip resistance analysis side load, for load center, i-th, overturning or slip resistance analysis side under the load situation preset is to the distance of pivot center, m is the load number of overturning or slip resistance analysis side under default load situation;

for the counter-force of the side jth anti-torsional bearing that topples under default load situation, to topple the distance of a jth anti-torsional bearing center in side to pivot center under the load situation preset, n is the number of anti-torsional bearing of side of toppling under default load situation;

Q _gfor the line severe of case beam, l ₀for case beam across footpath, l _qfor case beam center line and described pivot center distance in the horizontal direction.

Single column pier beam bridge rotates under uneven loading action, and now overturning does not occur bridge, equals the axis that topples (i.e. pivot center) of the principle calculating Single column pier beam bridge of resistance to tipping moment according to overturning moment.

For beam bridge, load is generally automobile, for the gravity of i-th automobile of overturning or slip resistance analysis side, calculated by gravity formulat according to quality.

In the present invention when calculated line type Single column pier beam bridge, its topple critical condition time each anti-torsional bearing counter-force can calculate by continuous beam computational methods.

In the present invention, the value of m and n changes along with practical situations.

Middle Single column pier produces vertical counter-force and the skid resistance along case soffit to case beam, and it is made a concerted effort by pivot center, and moment is zero.Can obtain thus, along with the increasing of unbalance loading, pivot center moves toward load action side gradually, and overturning moment is by end bearing counter-force, and the deadweight of case beam and the load being positioned at overturning or slip resistance analysis side provide.

In actual use, the load of Single column pier beam bridge both sides can change, and fully takes into account the loads change of overturning or slip resistance analysis side in the present invention, the carrying moment of the overturning or slip resistance analysis side that can accurately determine in real time.

As preferably, described overturning moment desired value L _oaccording to formula:

$L_O=\underset{t=1}{\overset{T}{\mathrm{\Σ}}}{P}_O\×l_o^t$

Calculate, wherein P _ofor load desired value of toppling, for load center and the described pivot center distance in the horizontal direction of toppling, T is the number of load of side of toppling.

The size of the bearing of Single column pier beam bridge is regulated to comprise the thickness increasing bearing radius, reduce bearing in step described in the present invention (3).When reinforcing Single column pier beam bridge, prioritizing selection increases the radius of bearing, then reduces the thickness of bearing, finally considers that increase is same as the distance between anti-torsional bearing again.

In actual applications size adjustable range be bearing original depth 10 ~ 80% between, the adjustable range of radius is R ~ R _d, wherein R _dfor bridge pier radius.

Do not make specified otherwise, it is same as anti-torsional bearing for defining two anti-torsional bearing be positioned on same bridge pier in the present invention.

If become three variablees (comprise thickness and the radius of bearing, and the distance between anti-torsional bearing) in the present invention simultaneously, the load that can make to topple improves more, namely improves resistance to capsizing, can formulate Scheme of Strengthening flexibly according to concrete service condition.

Compared with prior art, the reinforcement means of Single column pier beam bridge of the present invention is simple, be easy to realize, and just completes reinforcing, improve the resistance to capsizing of Single column pier beam bridge only by change supporting stand size.

Accompanying drawing explanation

Fig. 1 is the generalized section that the Single column pier beam bridge of the present embodiment is in head end when toppling critical condition;

Fig. 2 is the generalized section that the Single column pier beam bridge of the present embodiment is in bridge pier place arbitrarily in the middle of when toppling critical condition;

Fig. 3 strengthens supporting stand size to the effect diagram of the load of bridge overturning or slip resistance analysis;

Fig. 4 reduces bearing thickness to the effect diagram of the load of bridge overturning or slip resistance analysis;

Fig. 5 is that the spacing of increase end anti-torsional bearing is to the effect diagram of the load of bridge overturning or slip resistance analysis.

Detailed description of the invention

Describe the present invention below in conjunction with the drawings and specific embodiments.

This Single column pier beam bridge overturning or slip resistance analysis carrying moment is calculated for Shangyu, Zhejiang light of spring ramp bridge in the present embodiment.

This beam bridge adopts unidirectional two-way traffic (track, one, each direction), the wide 8m in cross section, the concrete size of box section: bridge pier diameter 1.1m, top rake 3.5%, each bridge pier is established the bearing of diameter D=600mm, thickness h=150mm, wherein head and the tail two ends are anti-torsional bearing, same as the distance l=2.1m in anti-torsional bearing between two anti-torsional bearing, bridge pier distance case lower flange of girder rim edge 0.4m.

The reinforcement means of the Single column pier beam bridge of the present embodiment, comprises the steps:

(1) for the load situation determination overturning or slip resistance analysis side of presetting and side of toppling, the load desired value and setting is toppled;

The load situation preset in the present embodiment is as follows:

4 overload carload lots are respectively 28.52t, 124.44t, 125.6t and 110.73t, and light car is in inner side, and three loaded vehicle pass through with comparatively low velocity from the side in outside.

Determine in the present embodiment that, with side, light car place for overturning or slip resistance analysis side, side, three loaded vehicle places is side of toppling.

3 carloads of side of toppling are 1.46m apart from case beam centre distances, and 1 automobile distance Xiang Liang center of overturning or slip resistance analysis side is about 1.64m.Carload applies according to (JTG D60-2004 highway bridge and culvert design general specification).The load of each automobile of side of now toppling is 120 tons, and for ensureing not topple, the automotive dead weight desired value of corresponding setting is 165 tons, and namely topple load desired value P _o=1617KN.

Setting is toppled the position of critical condition and now pivot center: setting topple critical condition time the pivot center of case beam of Single column pier beam bridge and the distance at bearing center equal the thickness of bearing.

Fig. 1 and Fig. 2 is that in the present embodiment, Single column pier beam bridge is in view when toppling critical condition, and its center line A is the center line of critical condition case beam of toppling, and line B is pivot center, and in Fig. 2, great circle region is the enlarged drawing in roundlet region.

As shown in Figure 2, the pivot center of critical condition nowel beam of determining in the present embodiment to topple is to the distance a=h at bearing edge, and wherein h is bearing thickness (150mm).

(2) the moment state equation of critical condition of toppling is built according to load desired value of toppling;

L _R＝L _O，

Wherein, L _rresistance to tipping moment under critical condition of toppling:

$L_R=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{P}_A^i\×l_A^i+\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{P}_B^j\×l_B^j+q_G\×l_0\×l_q,$

Calculate, wherein, for the load of i-th load in overturning or slip resistance analysis side, as shown in Figure 1, for load center, i-th, overturning or slip resistance analysis side under the load situation preset is to the distance of pivot center, n is the load number of overturning or slip resistance analysis side under default load situation;

according to following formulae discovery:

$l_A^i=L_A^i+(\frac{D}{2}-h)$

Wherein, for the distance at the automobile distance Xiang Liang center of overturning or slip resistance analysis side, be 1.64m in the present embodiment.

for the counter-force of the side jth anti-torsional bearing that topples under default load situation, as shown in Figure 1, to topple the distance of a jth anti-torsional bearing center in side to pivot center under the load situation preset, m is the number of anti-torsional bearing of side of toppling under default load situation;

according to following formulae discovery:

$l_B^j=L_B^j-(\frac{D}{2}-h)$

Wherein, for the distance at the anti-torsional bearing centre distance Xiang Liang center of side of toppling, be 1.05m in the present embodiment.

Q _gfor the line severe of case beam, l ₀for case beam across footpath, as shown in Figure 1, l _qfor case beam center line and described pivot center distance in the horizontal direction.

L _qaccording to following formulae discovery:

$l_q=\frac{D}{2}-h.$

In the present embodiment, overturning or slip resistance analysis side automobile quantity is 1, i.e. n=1, and quality is 28.52t.

The present embodiment m=2, the counter-force of each anti-torsional bearing adopts continuous beam computational methods to obtain, specific as follows:

Arrange vehicular load according to the actual loading position that topples of light of spring bridge, obtain the load that topples, then adopt continuous beam computational methods to calculate the counter-force of each bearing (anti-torsional bearing) under this load action that topples.

L _ofor overturning moment desired value, following formulae discovery can be utilized to obtain:

$L_O=\underset{t=1}{\overset{T}{\mathrm{\Σ}}}{P}_O\×l_o^t$

Calculate, wherein P _ofor load desired value of toppling, for load center and the described pivot center distance in the horizontal direction of toppling, T is the number (in the present embodiment T=3) of load of side of toppling.

according to following formulae discovery:

$l_O^t=L_O^t-(\frac{D}{2}-h)$

Wherein, for the distance at the automobile distance Xiang Liang center of side of toppling, in the present embodiment, be about 1.46m.

(3) regulate distance between the size of the bearing of Single column pier beam bridge or anti-torsional bearing to reinforce Single column pier beam bridge according to moment state equation.

When Fig. 3 is for fixing anti-torsional bearing spacing and bearing thickness, strengthen bearing diameter to the effect diagram of the load (the maximum load that topples that can bear) of bridge overturning or slip resistance analysis; When Fig. 4 is for fixing anti-torsional bearing spacing and bearing diameter, reduce bearing thickness to the effect diagram of the load of bridge overturning or slip resistance analysis; Fig. 5 be fixed bearing thickness and diameter time, increase the spacing (i.e. vertical displacement) of end anti-torsional bearing to the effect diagram of the load of bridge overturning or slip resistance analysis.Can find out and strengthen bearing diameter, or reduce bearing thickness, or the spacing increasing end anti-torsional bearing can increase the anti-supporting capacity of toppling of bridge.

If the anti-torsional bearing spacing l of anchor portion (head and the tail two ends), and change supporting stand size, now calculated by mechanics and geometry:

$P_A^1=28.52\×9.8\mathrm{kN},$

$l_A^l=(1.64+\frac{D}{2}-h)m,$

$P_B^1=1038\mathrm{kN},P_B^2=1012\mathrm{kN},$

$l_B^1=l_B^2=[\frac{2.1}{2}-(\frac{D}{2}-h)]m,$

q _G＝130kN/m，

$l_q=(\frac{D}{2}-h)m;$

Then limit resistance to tipping moment (being namely in the resistance to tipping moment of critical condition of the toppling) L of now beam bridge _rfor:

$L_R=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{P}_A^i\×l_A^i+\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{P}_B^j\×l_B^j+q_G\×l_0\×l_q=2610.87+13829.50\×(\frac{D}{2}-h)\mathrm{kN}\·m$

Owing to toppling parking stall, three, side on same track, then all cars in side that topple are all equal to the distance of pivot center, calculated in the present embodiment by geometry:

$l_o^1=l_o^2=l_o^3=[1.46-(\frac{D}{2}-h)]m;$

Then calculate overturning moment desired value L _o:

$L_O=\underset{t=1}{\overset{T}{\mathrm{\Σ}}}{P}_O\×l_o^t=[7082.46-4851(\frac{D}{2}-h)]\mathrm{kN}\·m.$

To substitute in moment state equation and solve and obtain:

$\frac{D}{2}-h\≈0.24m$

As fixed bearing thickness h=0.15m, during distance l=2.1m between anti-torsional bearing, using bearing diameter D as unknown quantity, substitute into moment state equation, solve and obtain bearing diameter D=0.78m, when namely strengthening bearing diameter to 0.78m, bridge overturning or slip resistance analysis bearing capacity can be made to increase to 165 tons by original 120 tons (by the actual measurement that destorys the scene, average per car is 120 tons to practical limit load).

As fixed bearing diameter D=0.6m, during distance l=2.1m between anti-torsional bearing, using bearing thickness h as unknown quantity, substitute into moment state equation, solve and obtain bearing thickness h=0.06m, it can thus be appreciated that when reducing bearing thickness to 0.06m, bridge overturning or slip resistance analysis bearing capacity to 165 ton also can be improved.

If fixed bearing size, and change the anti-torsional bearing spacing l at end (head and the tail two ends), now calculated by mechanics and geometry:

$P_A^l=28.52\×9.8\mathrm{kN},$

$l_A^l=1.79m,$

q _G＝130kN/m，

l _q＝0.15m，

$P_B^1=1038\mathrm{kN},P_B^2=1012\mathrm{kN};$

Then limit resistance to tipping moment (being namely in the resistance to tipping moment of critical condition of the toppling) L of now beam bridge _rfor:

$L_R=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{P}_A^i\×l_A^i+\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{P}_B^j\×l_B^j+q_G\×l_0\×l_q=500.30+(1038+1012)\×l_B^j+2340.00\mathrm{kN}\·m$

Owing to toppling parking stall, three, side on same track, then all cars in side that topple are all equal to the distance of pivot center, calculated in the present embodiment by geometry, then calculate overturning moment desired value L _o:

$L_O=\underset{t=1}{\overset{T}{\mathrm{\Σ}}}{P}_O\×l_o^t=6354.81\mathrm{kN}\·m.$

Substitute in moment state equation and obtain:

$2840.30+2050\×l_B^j=6354.81;$

Solve further and obtain:

$l_B^j\≈1.71m,$

Then $l=2\×(l_B^j+R-h)=3.72m,$

Anti-torsional bearing spacing by two ends increases to 3.72m, and the load that topples of this Single column pier beam bridge can be made can be increased to 165 tons.

Above-described detailed description of the invention has been described in detail technical scheme of the present invention and beneficial effect; be understood that and the foregoing is only most preferred embodiment of the present invention; be not limited to the present invention; all make in spirit of the present invention any amendment, supplement and equivalent to replace, all should be included within protection scope of the present invention.

Claims (7)

1. a Single column pier beam bridge overturning or slip resistance analysis reinforcement means, is characterized in that, comprise the steps:

(1) for the load situation determination overturning or slip resistance analysis side of presetting and side of toppling, the load desired value and setting is toppled;

(2) the moment state equation of critical condition of toppling is built according to described load desired value of toppling;

(3) regulate distance between the size of the bearing of Single column pier beam bridge or anti-torsional bearing to reinforce Single column pier beam bridge according to described moment state equation.

2. Single column pier bridge reinforcement method as claimed in claim 1, is characterized in that, described load desired value of toppling is 1.3 ~ 2 times of side load of toppling under default load situation.

3. Single column pier bridge reinforcement method as claimed in claim 2, it is characterized in that, during critical condition of toppling, the pivot center of the case beam of Single column pier beam bridge and the distance at bearing center equal the thickness of bearing.

4., as the Single column pier bridge reinforcement method in claims 1 to 3 as described in any one, it is characterized in that, described in the topple moment state equation of critical condition as follows:

L _R＝L _O，

Wherein, L _rresistance to tipping moment under critical condition of toppling:

L _ofor overturning moment desired value, according to toppling, load desired value calculates.

5. Single column pier bridge reinforcement method as claimed in claim 4, is characterized in that, the resistance to tipping moment L under described critical condition of toppling _raccording to formula:

$L_R=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{P}_A^i\×l_A^i+\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{P}_B^j\×l_B^j+q_G\×l_0\×l_q,$

Calculate, wherein, for i-th load of overturning or slip resistance analysis side under default load situation, for load center, i-th, overturning or slip resistance analysis side under the load situation preset is to the distance of pivot center, n is the load number of overturning or slip resistance analysis side under default load situation;

for the counter-force of the side jth anti-torsional bearing that topples under default load situation, to topple the distance of a jth anti-torsional bearing center in side to pivot center under the load situation preset, m is the number of anti-torsional bearing of side of toppling under default load situation;

Q _gfor the line severe of case beam, l ₀for case beam across footpath, l _qfor case beam center line and described pivot center distance in the horizontal direction.

6. Single column pier bridge reinforcement method as claimed in claim 4, is characterized in that, described overturning moment desired value L _oaccording to formula:

$L_O=\underset{t=1}{\overset{T}{\mathrm{\Σ}}}{P}_O\×l_o^t$

Calculate, wherein P _ofor load desired value of toppling, for load center and the described pivot center distance in the horizontal direction of toppling, T is the number of load of side of toppling.

7. Single column pier bridge reinforcement method as claimed in claim 4, is characterized in that, regulates the size of the bearing of Single column pier beam bridge to comprise increase bearing radius, reduces the thickness of bearing in described step (3).