The integral reinforcing method of Through Concrete-filled Steel Tubular Arch Bridge
The present invention relates to the bridge technology of highway and urban road, especially relate to a kind of integral reinforcing method of Through Concrete-filled Steel Tubular Arch Bridge.
Data shows, and the Major Diseases form of the concrete-filled steel tubes arch bridge that highway and urban road are commonly used comprises arch rib steel pipe and node cracking, the corrosion of suspension rod and tie-rod, fatigue failure, the damage etc. of bridge deck component.A series of safety problems such as above-mentioned disease brings concrete-filled steel tubes arch bridge total bearing capacity and Stiffness, and Local Members is damaged.
Under normal circumstances, for the above-mentioned disease that concrete-filled steel tubes arch bridge occurs, the following traditional reinforcement means of many employings solves:
1) when main arch compressive strength, rigidity, stable deficiency, adopt outside steel pipe fill concrete, reinforced concrete enveloped or set up the Enlargement of Sections such as cover arch and reinforce, shortcoming is when utilizing the method to reinforce arch rib, can increase arch rib deadweight, affect the landscape effect of structure;
2), when binder tensile strength is not enough, adopts and paste fibrous composite reinforcing, although the method can limit crack progressing and to defective strengthening of welded seam, be only limitted to local stiffening or reinforcement;
3), during suspension system Lack of support, reinforce by changing suspension rod, the method can solve corrosion and the problem of fatigue damage of suspension rod, but in the process changing suspension rod, needs to suspend traffic, bring adverse effect to the normal use of road.
Meanwhile, above-mentioned traditional reinforcement means all can only improve the bearing capacity of component, solves the damaging problem of component, not obvious to the raising effect of arch bridge total bearing capacity and rigidity.And along with socioeconomic fast development, China's communication occurred heavy duty, at a high speed, the transport structure feature of large discharge, built concrete-filled steel tubes arch bridge total bearing capacity and the problem of insufficient rigidity bring huge problem will to the development of city and highway communication.
Summary of the invention
A kind of integral reinforcing method provided for Through Concrete-filled Steel Tubular Arch Bridge total bearing capacity and insufficient rigidity problem is provided.
For achieving the above object, the present invention can take following technical proposals:
The integral reinforcing method of Through Concrete-filled Steel Tubular Arch Bridge of the present invention, carry out according to following step: ensure that former arch bridge arch springing lengthwise position is constant, above former arch rib, new arch rib is installed, after new arch rib is shaping, in the old suspension rod both sides of former arch bridge, new suspension rod is installed, adopt the method for load application step by step, original suspender force is progressively transferred on new suspension rod; After completing all new and old suspension rod replacements successively, the arch ring blocking former arch rib makes it to become statically determinate structrue, then removes arch ring by vault to arch springing is progressively symmetrical, completes the reinforcement of overall arch bridge.
Described new arch rib is steel pipe concrete arch rib, steel box arch rib or steel concrete arch rib.
Reinforcement means of the present invention is compared with traditional reinforcement means, and its advantage is mainly reflected in following several aspect:
1) in reinforcing process, bridge way is without the need to line-break, and social benefit is good;
2) compared with old arch rib, new arch rib ratio of rise to span increases, and the axle power of each controlling sections of arch rib and moment of flexure reduce, and optimize the stress of overall arch bridge structure, bus capacity is significantly improved;
3) ratio of rise to span owing to reinforcing rear arch bridge increases, and under dead load, former binder axle pulling force reduces, and under vehicular load, the Fatigue Stress Amplitude of binder reduces, and the degree of safety of binder significantly improves, and the supporting capacity of arch bridge entirety significantly improves;
4) two suspension rod is arranged to after reinforcing in the suspension rod both sides of former arch bridge, be convenient to change suspension rod from now on, can be undertaken by root under uninterrupted traffic or of short duration close traffic, without the need to extra temporary measure, less to bridge influence on system operation, and two suspension rod system add for improving suspension rod anti-fatigue performance advantageously;
5) compared to traditional arch rib external wrapping concrete reinforcement means, reinforcement means of the present invention meets the needs of Bridge Landscape.
Accompanying drawing explanation
Fig. 1, Fig. 2, Fig. 4, Fig. 5, Fig. 6 are the construction schematic diagrames of the inventive method.
Fig. 3 is the sectional view of Fig. 2 hogging 1/4th across place.
Detailed description of the invention
Below in conjunction with accompanying drawing, reinforcement means of the present invention is further described in detail.
The first step, first according to actual requirement of engineering, select the construction method of satisfactory rib structure (steel pipe concrete arch rib, steel box arch rib or steel concrete arch rib) and correspondence thereof, as erection with cableway (being comparatively suitable for steel pipe concrete arch rib and steel box arch rib), cast-in-place cantilever method (being comparatively suitable for steel concrete arch rib), construction by swing (being suitable for all arch rib forms), stiff skeleton method (being comparatively suitable for steel concrete arch rib), the erection work of new arch rib 2 is completed, as shown in Figure 1 above former arch rib 1;
Second step, first the Suo Li of old suspension rod 3 and floor elevation are tested or measured, then install a pair new suspension rod 4 in the bilateral symmetry of old suspension rod 3, the bridge floor anchor system 5 of the new suspension rod 4 of same section should be symmetrical with binder 6 in former bridge, as shown in Figure 2 and Figure 3; Adopt the method for multistage loadings (release), Suo Li on old suspension rod 3 is progressively transferred on new suspension rod 4: for guaranteeing that therefore bridge floor can not occur large STRESS VARIATION, Suo Li design load is divided into multistage, be applied on new suspension rod 4 step by step, hocket by batch cutting of the stretch-draw and old suspension rod of cutting off the new suspension rod of old suspension rod 3(accordingly), as shown in Figure 4; In the overall process of Suo Li conversion, tracking and monitoring Suo Li should be noted and change the elevation situation of change at suspension rod place place and the STRESS VARIATION situation at crucial cross section (referring generally to eight branches, quartile and span centre point) place, observing bridge floor has free from flaw to produce, also should carry out the measurement of point of proximity floor elevation, to judge whether to need to adjust Suo Li simultaneously; Carry out the replacement of other suspension rods of arch rib more successively according to the replacement order designed in advance, form structure as shown in Figure 5;
3rd step, after old suspension rod 3 is replaced completely by new suspension rod 4, take safety measures at the vault of former arch rib 1, control the inner force and displacement of arch ring truncation surface, upper and lower, the left and right changing of the relative positions is produced instantaneously in order to avoid open at vault, or produce and collapse out suddenly or phenomenon even at the cost of one's life again, as by adjustment jack shore power, force value in the theory of crown section is made to be zero or close to zero, then the disposable full arch circle that blocks makes it to become statically determinate structrue, and then remove arch ring by vault to arch springing is progressively symmetrical, complete the replacement work of arch rib, the arch bridge after reinforcing is as shown in Figure 6.
Reinforce not becoming across footpath of rear arch bridge, rise increases, and ratio of rise to span increases, and for three hinged arch, supposes that arch rib across footpath is
, rise is
, arch rib bears evenly distributed load
, its impost horizontal thrust that is easy to get is
.1/6 is changed to from 1/5, the change of concrete analysis impost horizontal thrust: establish for major arch rib ratio of rise to span
=100m, works as ratio of rise to span
when being 1/6, its horizontal thrust
for 2250KN, work as ratio of rise to span
when being 1/5, its horizontal thrust
for 1875KN, the change procedure that impost horizontal thrust increases with ratio of rise to span sees the following form:
As can be seen from the table, when across footpath one timing, the horizontal thrust of arch springing increases along with ratio of rise to span and reduces, and corresponding, its axle pulling force of the binder of tied arch also significantly reduces thereupon.