The method of cyclic longitudinal sliding continuous concrete span bridge
The invention relates to the construction of pre-stressed concrete spans different sections and cross-sections, especially now when the need for construction of superstructures on existing buildings, structures, communications, deep ravines and other obstacles located on the axis of the bridge. The method of cyclic longitudinal sliding supports continuous concrete span bridge with the side walls or ribs and the top or bottom plate and reinforcement in the form of direct beams of the upper plate and the inner side of the side walls or ribs includes concreting formwork sections spans, their reinforcement and connection is first made of sections with awebcam, whose length is 50-65% of the length connected with it a section of the superstructure with subsequent sliding the pushing Jack with increase in the following sections. The casing is made of two with pillow slip parts: the first, lower, based on four hydraulic jacks and used for concreting the bottom plate, the second is used for concreting the side walls or edges and for concreting the top plate. The formwork sections are placed for talkhaus is possible through single strands, which pull odnorazovye jacks. The sliding produce at the rate of 7.5-12.5 m/h develop a pusher jacks horizontal force not exceeding half the magnitude of the vertical force generated is additionally used when sliding, lifting jacks. After all the sections of the superstructure in a project position in their side walls or ribs placed tense transit beams valve, the length of which is not less than the length of the three sections of the superstructure, and merges the valve all sections of the superstructure. The technical result consists in the reduction of construction time and special auxiliary systems in spans. 3 Il.
The proposed method relates to the construction of pre-stressed concrete spans different sections and cross-sections. Especially this method is effective when the need for construction of superstructures on existing buildings, structures, communications, deep ravines and other obstacles located on the axis of the bridge.
Known methods of construction of reinforced concrete superstructures by rzeczami, separate installation of the precast beams are then combined in nerazreznoy above the supports or near the supports, and the method concrete superstructure on a solid scaffolds may not be applied when passing highway bridge over the buildings, structures and other obstacles due to the limited construction height or inability to place scaffolding and crane mounting equipment on existing buildings.
From the closest known is the method of construction of the bridge, trestle, characterized in that it includes the erection of poles and at least one continuous along the length of the span of forming at least one cross-section of the branch concrete longitudinal beams that carry on the stocks of in-situ or precast-monolithic reinforced concrete by concrete in the removable casing section by section with reinforcement UN-tensioned and pre-tensioned reinforcement, followed produced using averbeke longitudinal cyclic sliding sections before placing each of them in a project position, thus pre-tensioned reinforcement is placed in the closed channels in the form of beams, including formed of wire strands (ropes), and/or stereodecoder or polymer filaments, moreover, some of the channels perform straightforward, as part of the channel is curved or polygonal configuration and location mainly in vertical section of convexity and concavity corresponding to or proportional to the plot of bending moments, a working valve, located in the straight channels, strain within each section before sliding, and moving from the building Board, and a valve located in a curved or polygonal channels, push or stretch in the channels after sliding the whole span or ndigenous its branches and strain after sliding all sections constituting the superstructure, or navigaia part, or branch, the ratio of the squares of the cross-section and/or carrying capacity of the valve, pre-tensioned by sections, and fittings, pre-tensioned after sliding in the design position all ndigenous part or branch of the superstructure, take the calculation. The stocks perform from the base, uprights, beam cells and resting on jacks formwork with concrete walls, which have the edges and the axis of the concrete section of the superstructure, and on top of the walls of the stack of steel plates, the joints of which the governmental silicone, on top of the steel sheets stacked sheets of plywood in length, the smaller the distance between the formwork and additional support near her, and a width greater than the width of the steel sheets. Before concreting sections produce placement of kanaloobrazuyuschego in the design position on the reinforcement pads, which have a distance from each other along kanaloobrazuyuschego, then set in the design position of the anchor, produce the formation of beams of high-strength strands in installed kanaloobrazuyuschego of securing the strands in the anchor devices, make the connection of kanaloobrazuyuschego with anchor devices to seal all joints in the upper and lower points of inflection of the valve in transit kanaloobrazuyuschego install additional drainage tube, and transit canadaontario fill the plastic tubing to impart greater rigidity to kanaloobrazuyuschego, cutting high-strength strands are produced by mechanical means, and after concrete section of the superstructure design strength produce high-strength tension beams, while injectiona tight valves produced before or directly after sliding the partition p is s for each partition individually in accordance with the perceived load. When performing a partition plate-ribbed or box concreting sections of the superstructure on the stocks produced in two stages, the first of which is concreted at the same time two ribs or ribs and the bottom plate of the box girder. When performing sections of the superstructure slab concreting sections are produced in one stage, for which the frame elements are mounted casing section. After concreting sections of the superstructure produce exothermic curing of the concrete. The sliding spans produce four jacks, which are mounted in front of the abutment with connectivity via four rebar with steel beams, mounted in a floating structure, and for sliding the first section spans two of the four rods attached to averbeke. The superstructure is based on free-standing reinforced concrete poles rectangular cross-section (RU # 2208084 C1, CL E 01 D 21/00, 2003).
The proposed solution does not require special auxiliary systems in bays where there are obstacles, and can be implemented with limited construction height of the concrete spans, which opredelaetsa the ton of the superstructure of the bridge with the side walls or ribs and the top or bottom plate and reinforcement in the form of direct beams of the upper plate and the inner side of the side walls or ribs includes concreting formwork sections spans, their reinforcement and connection is first made of sections with awebcam, whose length is 50-65% of the length connected with him sections of the superstructure with subsequent sliding the pushing Jack with increase in the following sections, while the formwork is made preferably of two with pillow slip parts: the first, lower, based on four hydraulic jacks and used for concreting the bottom plate, and the second is used for concreting the side walls or ribs and concrete top slabs and formwork sections are placed for pushing jacks on the length of one section of concrete and Amanbek attached to the front section of the superstructure by means of single strands, which pull odnorazovye jacks, sliding produce at the rate of 7.5-12.5 m/h develop a pusher jacks horizontal force not exceeding half the magnitude of the vertical force generated is additionally used when sliding, lifting jacks, and after all the sections of the superstructure in a project position in their side walls or ribs placed tense transit beams valve, the length of which is not less than the length of the three sections prole the Xia drawings, where:
in Fig.1 shows a diagram of the concreting of the first section and installation of averbeke,
in Fig.2 shows a diagram of the sliding spans using averbeke and concreting of the second section,
in Fig.3 shows a diagram of the sliding spans using averbeke and concreting of the third section.
Auxiliary arrangement with the proposed method works located outside Podmoskovya dimensions:
- slipway-polygon 1 formwork for concreting sections 2 spans;
- steel Amanbek 3, which is temporarily attached to section 2 reinforced concrete spans for a period of sliding in order to reduce bending moments and shear forces in the cross section of the superstructure when the sliding;
- pushing device 4 for the longitudinal sliding of the sections 2 of the span.
Concrete span structure in the same sections for longitudinal sliding feels different (including alternating) efforts. Therefore, a required element of each stage of sliding is installing or removing (sometimes both) temporary high-strength beams and installation of transit reinforcement prestress after sliding on supports which, the days of which raise the section of the superstructure, and the other pushing. A floating structure used canadaontario (for example, patent No. 2178046).
Above each pillar 5 establish special bearer, on which slides the superstructure.
The method of cyclic longitudinal sliding (CNS) is the concreting of the individual parts of the superstructure in place, and 1/3 or 1/2 of the span is located in the covered slipway-the ground directly behind one of the pillars. Each concrete section “hook” continuous spans Prajnaparamita before sliding. For sliding uses a special hydraulic equipment and the supporting part with a low coefficient of friction, on which the superstructure is moved over the intermediate supports. Technical advantages of this construction with concrete on site include the following:
- on the ground realized the advantages of prefabrication due to the repeatability of the business operations and the independence of the works from the weather conditions,
- excludes scaffolding, Assembly and disassembly are associated with time-consuming, and by the constraint of an existing movement,
eliminated frequent deformation or the UDA and the cost of formwork. The reduction in the value of these components can be obtained by:
- repetition of similar operations,
- reuse easily assembled and reassembled shapes and designs,
preliminary procurement of conventional and prestressed reinforcement,
- transportation of materials over short distances,
good quality control of concrete work,
- protection zone of the works from the weather conditions that guarantee the execution of the works on schedule,
- reusability scaffolding and equipment other works,
- reduce labor costs and ensure the highest control over the work due to the concentration of much of the work inside the indoor of the polygon.
In General, MTC method is applicable for the construction of bridges on both straight and curve of the same radius. The curve may be in the vertical plane. Based on this method bridges have a length of from 100 to 1200 m, But the minimum length of the bridge should be about 300 m to amortize the cost of formwork and equipment and to make this method competitive. It is not necessary that the bridge had the same spans. If one or two flights have a greater length than the other, can be carried spans should be within 75% of the medium spans. The value of Central prestress for sliding is very important, so you need to carefully select the cross-section designs in the design. The correct position of the concrete sections on the ground and ensuring accurate vertical position of the casing has a main importance for a successful launching. The casing is usually made of two parts ready: one for the bottom plate and the second for the side walls or ribs and the top plate. This separation ensures work week production cycle of one section of the superstructure and provides maximum performance, especially for large bridges. Can be used and a separate one-piece casing with a corresponding reduction in costs of landfill, but in this case, the duty cycle will be 8 days to care for a concrete inner surface within 24 hours prior to the concreting of the upper plate. The function of the Central voltage is the perceptual cross-section of the superstructure of all positive and negative points for any change in the position it over the supports. Direct the beams in the upper plate and the inner side of the side walls have a butt couplings-stars and beams in a relatively thin upper and lower plates require special anchoring. In some cases, when a relatively large spans of the bridge (over 50 m) power Central prestress is too great for the last stage of construction. To exit the position, establish temporary beams, which is removed after installation of the superstructure in its final position. Transit beams are installed when launching is completed and the superstructure took a design position. These beams, the length of which reaches 90-100 m depending on the spans of the bridge are located in the side walls of the superstructure with the location of the anchors with the inner side of the box section for aesthetic reasons.
There are two alternative methods cyclic longitudinal sliding.
And}. Pulling method
This method uses conventional jacks for prestress and praevia bundles that allow you to pull the superstructure by means of a frame attached to the rear end of the penultimate section.
B}. Method of pushing
This method uses a synchronized jacks underneath the superstructure that lift and then push the superstructure due to friction between the steel Jack and concrete.
Method of pushing has significant preenumerate, for example, to reverse. This may be necessary, for example, due to the extremely large friction on the bearings when starting in cold weather, causing large deformations of the supports. The ability to immediately change the direction of motion in this case is very important. It is necessary to take into account some of the issues associated with the location of the pushing jacks, and it is very important to determine the acceptable size of the area to install the push equipment: for anchoring jacks used to transfer horizontal forces, as well as a place to install the brake shoes, which are steel plates, on which rests the superstructure of all time, excluding the time of sliding. Formwork is usually placed for pushing jacks on the length of one section of the concrete. This increases the vertical reaction on the jacks and balances the torque from the console.
In the design of supports, it is important to limit the horizontal force that acts on the lower part of the supports. When this occurs the maximum allowable deflection of support as a result of exposure to the maximum horizontal force and the allowable friction. The electronic control system, smonte who avoids their maximum values. Important is the correct placement of the supporting parts, taking into account tolerances in the arrangement of the flat jacks for hoisting the superstructure and permanent placement of bearing parts in a design position. For large horizontal forces (which arise when the second set of equipment on the pole N1) Association of temporary support is a feasible solution for the perception of these forces.
Polygon-the frame consists of one or two sites in the matter is concreted whether the casting section, complete the superstructure in one formwork or two. The landfill served by cranes, has a concrete plant and the area for production of reinforcement cages and execution of preduprezheniyu design. From the back side of the casing there is a paved area to protect the beams from possible contact with the ground. The system of rollers allows the beams comfortably during sliding of the superstructure. Typically, the polygon is removed from the abutment 15-20 meters. Between ground and Foundation have a temporary support with a spacing of 6-7 meters and sliding devices on them. Under the terms of multiple turnover casing is made of metal, wood is not used. The lower part of the casing are special guides, combined with neoprene-Teflon support pillows, providing a low coefficient of friction.The opening of the side parts of the casing and the internal casing (in the case of box-section) is also carried out using hydraulic Jack.
The final number of prestressed beams in the case of application of the method of CNS 40% more road bridges (rail a little less) in comparison with the method of concreting of the superstructure in place. This is because in addition to the Central preduprezheniyu necessary to produce the stress of transit beams. The number of permanent beams can be reduced by the introduction of temporary beams, which can be removed and reused in construction. In any case, the increase in the value of the prestress in the method far CNS overlaps many other benefits and savings. Device prestress use bundles of 100 tons capacity for highway bridges, railway bridges 170 ton capacity. The beams are joined in 2-3 concreting zahvatki with couplings on patents of the Russian Federation No. 2094578, 2094577. The beams of the upper plate wound on the reel, so as not to interfere with the work preparing the following is his have a length of 90-100 m, to ease the task of free push them into the channels, and have the tension anchors at each end. The tension of these beams is performed after final installation of the superstructure in the design position. However, the beams can be dragged in advance if it becomes necessary, but in this case, the channels need to fill in aqueous solution antikorrozionnoe compound, which must be washed out of the channel before injection.
Hardware for sliding comprises, for example, two jacks, one of which raises the superstructure, freeing it from the brake pillows, and the other provides the pushing of the superstructure. Speed sliding about 10 m/h, so concreted area with a length of 15-20 m can be nadenut for 2 hours. Temporary basic parts consist of a concrete slab with stainless steel sheet attached to the top surface for limiting the sliding friction. After sliding these basic parts are replaced by a constant, usually one fully-mobile and one linearly movable. Designed glass support part, which can be used as temporary, and as permanent. These basic parts consist of standard glass bearing parts with specalities during sliding. After sliding these basic parts are working as permanent pre-combined with wedges.
The process of transformation of temporary support parts in fixed using for these purposes the flat jacks becomes an easy operation if you are using special reference part. The side guides are designed so that they can be installed at any time during the sliding. These guides are connected to the supports by means of the beams.
Manufacturer of box girder with two sets of formwork is conducted in the following sequence.
Morning. The lowering of the bottom and the outer casing. Tension high strength reinforcement and launching.
After lunch. Cleaning and lubrication of the formwork. Preparation of the beams.
Tuesday. Installation of reinforcement and kanaloobrazuyuschego in the bottom plate.
Continued work on the reinforcement of the bottom plate. Install the valve top plate and wall. Concreting of the bottom plate.
Continued installation of the valve top plate and walls, installation of embedded parts for prestress.
Concreting of the walls and top slab.
The curing concrete. In sloto a team of 14 people produces a plot of the span (15-20 m) per week.
The method of cyclic longitudinal sliding supports continuous concrete span bridge with the side walls or ribs and the top or bottom plate and reinforcement in the form of direct beams of the upper plate and the inner side of the side walls or ribs, characterized in that it includes concreting formwork sections spans, their reinforcement and connection is first made of sections with awebcam, whose length is 50-65% of the length connected with him sections of the superstructure with subsequent sliding the pushing Jack with increase in the following sections, while the formwork is made of two with pillow slip parts: the first, lower, based on, preferably four, hydraulic cylinder and used for concreting the bottom plate, and the second, which is used for concreting the side walls or ribs and concrete top slabs and formwork sections are placed for pushing jacks on the length of one section of concrete and Amanbek attached to the front section of the superstructure by means of single strands that pull odnorazovye jacks, sliding produce with the HN vertical efforts, created additionally used when sliding, lifting jacks, and after all the sections of the superstructure in a project position in their side walls or ribs placed tense transit beams valve, the length of which is not less than the length of the three sections of the superstructure, and merges the valve all sections of the superstructure.
FIELD: building, particularly to construct steel reinforced concrete span structures.
SUBSTANCE: method involves mounting blocks formed as reinforced concrete flooring panels by moving thereof in horizontal direction with the use of pushing means across bridge span, wherein before panels installation on support span parts panel is laid on sleds with the use of load-lifting means, sleds are installed on track, guiding tracks are placed on sleeper grid consisting of wooden studs and two transversal members, rollers are arranged between sleeper grids; installing supplementary columns and four jack posts in addition to main supports. Flooring panel movement is performed with the use of pushing means which displaces sleds up to span to be overlapped. After that flooring panel is lifted by means of jack posts, sleds are removed and displaced into their initial position. Then track is rolled, flooring panel is lowered on bridge piers with the use of hydraulic cylinders of jack posts; free jack posts are dismounted and mounted in the next bridge span simultaneously with supplementary columns installation. Track is placed on previously installed flooring panel with sleds on which next flooring panel is laid. All above operations are repeated.
EFFECT: reduced time of bridge assemblage in urban areas.