CN104060542B - Compound beam cable stayed bridge direction across bridge prestress application device and applying method thereof - Google Patents

Abstract

The invention discloses a composite girder cable-stayed bridge cross-bridge direction prestress applying device and an applying method thereof, which belong to the field of bridge construction. For the arch truss, two anchor points are formed on the transverse diaphragm of the steel beam and the two middle webs. Jacks are set on the main girder on the top surface of the reverse arch truss at the above two anchor points to form two lifting points. Applying method: lift the tension rod by jack to apply counterforce until the anti-arch application is completed; after the wet joint concrete strength reaches more than 90% of the design strength, the jack returns to the oil, and after releasing the upward lifting force of the anti-arch truss, the steel girder cross bridge Shrink to rebound and squeeze the concrete structure, thus generating transverse compressive stress on the bridge deck. The invention is a safe, effective and practical application device and application method for the transverse preload of steel-concrete composite beams.

Description

Composite girder cable-stayed bridge cross-bridge direction prestressing device and its applying method

technical field

The invention belongs to the field of bridge construction, in particular to bridge superstructure construction.

Background technique

(1) Traditional construction:

Corner guide devices are installed at each corner of the steel beam side bottom plate, and hanging legs for installing anchors are installed at the top positions of the side webs on both sides. The prestressed steel strands are arranged along the steel beam side bottom plate. Anchored at the hanging leg at the top of the web on the side of the steel beam. Install a 100t jack on the simple support (made of angle steel) at the midpoint of the steel beam bottom plate, and use the jack to vertically lift and tension the prestressed steel strand to achieve the purpose of applying horizontal anti-arching force to the steel beam. Specifically as shown in Figure 1 of the accompanying drawings.

(2) Limitations of traditional construction:

①The anti-hogging force is applied by tensioning steel strands. Because it needs to cross 4 corners, the maximum corner is close to 90°, and the prestress loss is very large.

②The temporary fulcrum of the steel beam is located in the range of the diaphragm, and the prestressed steel beam also needs to be applied along the diaphragm, and there is a conflict between the two positions.

③ When the prestressed steel beam passes through the four corners of the steel beam, it is necessary to set up guide devices on the outside of the corners of the steel beam, and reinforcement measures must be taken on the inside to meet the force requirements. Except for the girder sections with wet joints, guides must be provided for the whole bridge, and the amount of reinforcement and cutting work is too large.

④ If the connection between the outer guide device and the inner reinforcing plate and the steel beam is connected by welding, there will be more damage to the anti-corrosion coating of the steel beam, and the amount of repainting in the later stage will be larger; if the bolted connection is used In the later stage, high-strength bolts are used to fill holes in the side webs and bottom plates of steel beams, which requires a large amount of work and the anti-corrosion of bolts is difficult.

⑤ It is difficult to relax after the anti-arching is completed, and it needs to be stretched beyond the anti-arching force, and the load can only be unloaded by withdrawing from the clip, which may cause concrete cracking.

⑥After the steel strand is tensioned, according to the requirements of the specification, the tensioning operators should be on both sides of the tensioning end, and the operators need to work between the tensioning ends for a long time, posing safety hazards.

⑦After the prestressed steel tendon is stretched in the open air, it can only be removed after the strength of the cast-in-place wet joint concrete reaches the design requirements. Electric welding and gas cutting have great potential safety hazards.

Contents of the invention

The object of the present invention is to find a safe, effective and practical application device and application method for the transverse preload of steel-concrete composite beams in view of many disadvantages and deficiencies of the prior art.

The object of the invention is achieved through the following technical solutions:

A composite girder cable-stayed bridge transverse bridge direction prestressing device, comprising a steel girder, and an inverted arch truss detachably installed on the top of the steel beam diaphragm, on the steel beam diaphragm and two middle webs Form the anchor point of the bolted structure of the two lugs, the outside of the reverse arch truss is connected and fixed to the outside of the web on both sides of the steel beam through the corbel to form two support points, and the top surface of the reverse arch truss at the two anchor points A jack is arranged on the main girder, and a tension rod connecting the jack and the anchor point is arranged through the reverse arch truss to form two lifting points.

In the above scheme, the prestressing device of the steel-concrete composite beam transverse bridge is optimized from the traditional way of applying prestress at the bottom of the beam section to the way of applying anti-arching force at the top of the beam section: Improves the turnover speed of the reverse arch truss between the beam sections, thus speeding up the on-site production schedule; The safety in the process of applying compressive stress to the transverse bridge is greatly improved. The tension rod of the anti-arch truss and the lifting lug at the position of the middle web are connected by pin shafts, which greatly reduces the operational difficulty and workload of the operators during the installation and disassembly of the anti-arch truss. The jack is arranged on the main girder on the top surface of the reverse arch truss mainly to facilitate the rapid installation and disassembly of the jack by using the existing lifting equipment.

As an option, one piece of the reverse arch truss is installed on each diaphragm of each steel beam, and three pieces of the reverse arch truss are arranged on a single beam section.

In the above scheme, by laying out the anti-arch truss on each diaphragm of each steel girder, after applying the anti-arch force, the transverse deformation value of each section of the steel girder can be consistent, so that the cross-bridge deformation of each section of the steel girder The same compressive stress is obtained.

As an option, the reverse arch truss is a trapezoidal body with a trapezoidal facade. The upper and lower chords are connected to the oblique rods and vertical rods of the upper and lower chords on the same side, and the upper and lower chords connected to the different sides. The connecting rod is connected and fixed.

In the above scheme, the anti-arch frame adopts the scheme of upper and lower chords, inclined bars, vertical bars, and connecting bars, and the overall design is a trapezoidal steel truss structure, which not only ensures that the stiffness of the truss can meet the structural The need for deformation reduces the overall weight of the anti-arch truss itself.

As an option, the reverse arch truss is composed of two pieces connected by bolts.

A method for applying the prestressing device to the transverse bridge of the aforementioned composite girder cable-stayed bridge. After each steel girder deck is installed in place and before the wet joints are poured, the reverse arch truss is installed in place, and the main girder of the reverse arch truss is installed. The jack on the top lifts the tension rod to apply the reaction force, forming the deflection of the web on both sides of the steel beam, and the convex anti-arch effect on the middle web until the application of the anti-arch is completed; after the strength of the wet joint concrete reaches more than 90% of the design strength, After the oil is returned from the jack and the upward lifting force of the reverse arch truss is released, the steel girders will rebound and shrink in the transverse direction, squeezing the concrete structure, thereby generating transverse compressive stress on the bridge deck.

In the above scheme, the bridge deck is installed before the reverse arch truss to facilitate the rapid installation and precise positioning of the bridge deck, as well as the binding of steel bars at wet joints and the connection of various pipes. After the concrete strength reaches more than 90% of the design strength, the upward lifting force of the inverted arch truss is released so that the transverse compressive stress on the concrete can be more effectively transmitted to the concrete when the steel beam deforms and rebounds.

The above-mentioned main scheme of the present invention and its further options can be combined freely to form multiple schemes, all of which are applicable and claimed schemes of the present invention: as in the present invention, each selection can be combined with other selections arbitrarily, and those skilled in the art After understanding the solution of the present invention, according to the prior art and common knowledge, it can be understood that there are various combinations, all of which are technical solutions to be protected by the present invention, and are not exhaustive here.

Beneficial effects of the present invention: from the measurement and implementation effects of the main girder section under various working conditions such as the installation of the anti-arch truss, application of anti-arch force, maintenance and removal, a piece of The anti-arch force applied by the anti-arch truss can not only meet the transverse compressive stress reserve required by the steel-concrete composite beam, but also improve the safety and operability of on-site construction, and at the same time speed up the production progress.

Description of drawings

Fig. 1 is the structural representation of prior art;

Fig. 2 is the elevation structure schematic diagram of the embodiment of the present invention;

Fig. 3 is a side structural schematic view of an embodiment of the present invention;

Fig. 4 is a schematic plan view of an embodiment of the present invention;

Among them, 1 is the steel beam, 2 is the diaphragm, 3 is the middle web, 4 is the anchor point, 5 is the corbel, 6 is the side web, 7 is the main beam on the top surface of the reverse arch truss, 8 is the jack, and 9 is the tension Pull rod, 10 is the upper chord, 11 is the lower chord, 12 is the oblique rod, 13 is the vertical rod, 14 is the connecting rod, 15 is the jack shelving bracket, 16 is the steel strand, 17 is the corner, 18 is the anchorage, 19 is hanging legs.

Detailed ways

The following non-limiting examples illustrate the invention.

As shown in Figure 2-4, a composite girder cable-stayed bridge cross-bridge prestressing device, including a steel beam 1, and a reverse arch truss detachably installed on the top of the steel beam 1 transverse diaphragm 2, each piece of steel Three anti-arch trusses are installed on the three transverse partitions of beam 1, and three anti-arch trusses are arranged on a single beam section. The anchor point 4 of the bolted structure with two lugs is formed on the transverse diaphragm 2 of the steel beam 1 and the two middle webs 3, and the outer side of the reverse arch truss is connected and fixed with the outer sides of the webs 6 on both sides of the steel beam 1 through the corbel 5 to form two support points , and a jack 8 is set on the main beam 7 of the reverse arch truss top surface of the two anchor points 4, and a tension rod 9 connecting the jack 8 and the anchor point 4 is set through the reverse arch truss to form two lifting points. As an option, the inverted arch truss is a trapezoidal body with a trapezoidal facade, which is composed of two pieces connected by bolts (the left and right sections are connected as shown in the figure), and the whole is composed of upper and lower chords 10, 11 connected on the same side Upper and lower chords 10, 11 oblique bars 12, vertical bars 13, and connection rods 14 connecting the upper and lower chords 10, 11 on different sides are connected and fixed, and [40 channel steel can be used to make the upper and lower chords and [14 grooves Steel is used as oblique rods, vertical rods and connecting rods.

A method for applying the prestressing device to the transverse bridge of the aforementioned composite girder cable-stayed bridge. After each steel girder deck is installed in place and before the wet joints are poured, the reverse arch truss is installed in place, and the main girder of the reverse arch truss is installed. The jack on the top lifts the tension rod to apply the reaction force, forming the deflection of the web on both sides of the steel beam, and the convex anti-arch effect on the middle web until the application of the anti-arch is completed; after the strength of the wet joint concrete reaches more than 90% of the design strength, After the oil is returned from the jack and the upward lifting force of the reverse arch truss is released, the steel girders will rebound and shrink in the transverse direction, squeezing the concrete structure, thereby generating transverse compressive stress on the bridge deck.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (4)

1. A method for applying the prestressing device to the cross bridge of a composite girder cable-stayed bridge, the device for applying the prestressing force to the cross bridge of a composite girder cable-stayed bridge comprises a steel girder, and a reflector that is detachably mounted on the top of the steel girder diaphragm For the arch truss, an anchor point of the bolted structure of two lugs is formed on the top surface of the connection between the steel beam diaphragm and the two middle webs, and the outer side of the reverse arch truss is connected to the outer sides of the webs on both sides of the steel beam through corbels Two supporting points are fixed, and jacks are installed on the top main beam of the reverse arch truss at the two anchor points, and tension rods connecting the jacks and anchor points are installed through the reverse arch truss to form two lifting points. It is: after each piece of steel girder bridge deck is installed in place and before the wet joints are poured, the reverse arch truss is installed in place, and the jack on the top main girder of the reverse arch truss is used to lift the tension rods to apply the reaction force to form the webs on both sides of the steel girder. The slab is deflected downward, and the anti-arching effect on the mid-web is completed until the anti-arching application is completed; after the concrete strength of the wet joint reaches more than 90% of the design strength, the jack returns to the oil, and after releasing the upward lifting force of the anti-arching truss, the steel beam cross The bridge rebounds and shrinks, squeezing the concrete structure, thereby generating transverse compressive stress on the bridge deck. 2. The method for applying the prestressing device to the cross bridge of the composite girder cable-stayed bridge as claimed in claim 1, characterized in that: a piece of said reverse arch is installed on each diaphragm of each piece of said steel girder For the truss, three anti-arch trusses are arranged on a single beam segment. 3. composite girder cable-stayed bridge transverse bridge as claimed in claim 1 is characterized in that: described anti-arch truss is a trapezoidal trapezoidal body in a facade, by upper and lower chords, The oblique rods and vertical rods connecting the upper and lower chords on the same side, and the connecting rods connecting the upper and lower chords on the different sides are connected and fixed. 4. The method for applying the prestressing device to the transverse bridge of the composite girder cable-stayed bridge according to claim 1, characterized in that: the reverse arch truss is composed of two pieces connected by bolts.