Disclosure of Invention
The invention provides a bridge precast slab with reduced weight and firm internal steel bar structure, which can improve the bearing capacity and firmness of a bridge and a construction method of the bridge precast slab, and aims to solve the technical problems that the existing bridge precast slab is complex in manufacturing process and simple in internal steel bar structure, so that the bearing capacity of a bridge deck is low and the bridge structure is unstable in bearing.
The following technical scheme is provided for achieving the purpose: a bridge precast panel comprising: the bearing body and pour the reinforcement cage in the middle of the bearing body, its characterized in that, it consolidates the cage including first reinforcement cage and second to consolidate the cage, first reinforcement cage and second are consolidated the cage structure and are the same to be formed by the extension of supporting part and perpendicular to supporting part, the second is consolidated the cage and is arranged in first reinforcement cage inside, consolidate the cage and evenly lay in the bearing body inside, be equipped with the lifting hook on the bearing body, the bearing body both sides are equipped with the connecting portion of outside extension. The first reinforcing cage and/or the second reinforcing cage are formed by bending a reinforcing bar into a rectangular shape, fixing structures at two ends of the reinforcing bar by welding and reinforcing bar structures welded (or bound by steel wires) at four corners of the rectangular shape, and the corners of the rectangular shape are correspondingly welded together by the reinforcing bar between the first reinforcing cage and the second reinforcing cage. The lifting hook is welded on the supporting part.
Further, the connecting parts are respectively arranged on the upper side and the lower side of the bearing plate, and the connecting parts and the bearing plate are of an integrated structure.
Furthermore, a third reinforcing steel bar is transversely distributed in the connecting part.
Furthermore, the sum of the thicknesses of the connecting parts is 1-1.5cm smaller than that of the bearing plate.
Furthermore, the length of the connecting parts at the two sides of the bearing body is the same and is 2-3 cm.
Furthermore, at least 3 reinforcing cages are arranged in the bearing body.
The construction method of the municipal bridge precast slab provided by the invention comprises the following steps:
firstly, cutting a first steel bar into three sections according to a certain length, wherein the three sections are respectively a first section of steel bar, a second section of steel bar and a third section of steel bar, and the lengths of the first section of steel bar, the second section of steel bar and the third section of steel bar are sequentially reduced; step two, bending the first section of reinforcing steel bars and the second section of reinforcing steel bars into a first rectangle and a second rectangle to serve as supporting parts, placing the second rectangle in the first rectangle in parallel, staggering the openings of the first rectangle and the second rectangle, and connecting the first rectangle with the second rectangle through the third section of reinforcing steel bars; step three, fixedly connecting second reinforcing steel bars at four corners perpendicular to the first rectangle and the second rectangle to be used as extension parts, uniformly distributing supporting parts in the length direction of the second reinforcing steel bars, vertically distributing lifting hooks and a plurality of lifting hooks along the supporting parts, and vertically fixing the lifting hooks on the supporting parts through steel wire binding or welding connection; step four, firstly, paving a layer of diaphragm at the bottom of the mould, then placing hollow air bags in a reinforcing cage, uniformly and transversely arranging a plurality of reinforcing cages with the hollow air bags in the mould, then adding mortar for pouring, vibrating by using a vibrating rod during pouring to compact the mortar, vibrating for 3-5min, and then compacting and strickling the surface of the mortar by using a material scraper to form a bearing body; cushion blocks are arranged at two ends of the hollow air bag, so that the reinforcing cage is positioned in the middle of the thickness direction of the die; taking the bearing bodies out of the mold after 20-30 hours, simultaneously taking out the hollow air bags, sequentially stacking the bearing bodies, separating the middle of each bearing body by using a wood block, and intensively watering for maintenance, wherein the maintenance time is 5-6 days; and sixthly, placing the bearing bodies on the bridge piers, wherein the joint of each bearing body is positioned on the bridge piers, and pouring and sealing the joints of the ends of the bearing bodies by using mortar. Before installation, the bearing body with cracks on the surface is picked out, and the bearing body is used after the cracks are repaired.
Further, the method for manufacturing the connecting parts on the two sides of the load bearing body further comprises the following steps:
firstly, when the middle of a bearing body is poured, mortar is flatly laid on two sides of a mould and vibrated by a vibrating rod, so that the mortar is compacted; uniformly placing a plurality of third reinforcing steel bars on the mortar with the two sides being compact; thirdly, paving mortar on the third reinforcing steel bar, vibrating by using a vibrating rod to compact the mortar, compacting and strickling the surface of the mortar by using a scraper after vibrating for 3-5min, and finishing the pouring of the connecting part; and step four, attaching the connecting parts on the two sides of the bearing plate to each other during installation.
The invention has the beneficial effects that: the bridge precast slab is internally poured by the reinforcement cages which have the same two-layer structure and are connected by welding, and at least three reinforcement cages are arranged side by side at the same time, so that the weight of the precast slab can be reduced by the hollow interior of the reinforcement cage while the firmness and the bearing of the bridge precast slab are increased. In addition, the connecting parts at two sides of the bridge precast slabs can realize seamless tight connection between the precast slabs, and the phenomena that the bridge floor is sunk to crack and the like due to low stress at the connecting part after being used for a long time can be avoided.
The construction method of the bridge precast slab can shorten the construction period of the bridge, improve the bearing capacity of the bridge and realize seamless tight connection between the bridges, and the invention further reduces the manufacturing cost of the bridge because the manufactured precast slab is hollow.
Detailed Description
The invention is further described below with reference to the accompanying drawings.
The invention provides a construction method of a municipal bridge precast slab and a bridge precast slab manufactured by using the method.
As shown in fig. 1, the structure of the bridge prefabricated slab comprises: the bearing body 1 and pour reinforcement cage 2 in the middle of the bearing body, it reinforces the cage 22 including first reinforcement cage 21 and second to consolidate the cage 2, first reinforcement cage and second are consolidated the cage structure and are the same to be formed by extension 24 of supporting part 23 and perpendicular to supporting part, second reinforcement cage 22 is consolidated inside cage 21 is arranged in first reinforcement cage, consolidate cage 2 and evenly lay in the bearing body 1 inside, consolidate the number of cage and set up 3 at least. The bearing body 1 is provided with a lifting hook 3, and two sides of the bearing body are provided with connecting parts 11 extending outwards. Connecting portion 11 sets up respectively at bearing plate upside and downside, connecting portion and bearing plate integral type structure transversely lay the third reinforcing bar in the connecting portion. The sum of the thicknesses of the connecting parts is 1-1.5cm smaller than that of the bearing plate, so that the connecting parts can be embedded in the bearing plate during assembly, and a certain space is reserved for expansion with heat and contraction with cold of the bearing body during use. The length of the connecting parts 11 at the two sides of the bearing body is the same and is 2-3 cm. Meanwhile, a through hole is formed in the precast slab, and a lead bar or a hollow air bag is filled in the second reinforcement cage during pouring to form the through hole structure.
Wherein: the first reinforcement cage and/or the second reinforcement cage are mainly composed of a second reinforcement bar bent into a rectangular shape and welded or tied with steel wires at four corners of the rectangular shape, wherein the rectangular reinforcement bar is a support portion, the second reinforcement bar welded at four corners of the rectangular shape is an extension portion, the second reinforcement cage is disposed inside the first reinforcement cage, and the four corners of the second reinforcement cage and the support portion of the first reinforcement cage are correspondingly welded and connected by a third section of reinforcement bar, as shown in fig. 2. The interior of the reinforcement cage is of a hollow framework structure, and the reinforcement cage is poured in the precast slab. By adopting the prefabricated slab with the structure, on one hand, the reinforcing cage is welded and connected by two layers of steel reinforcement framework structures and then poured in the prefabricated slab, so that the prefabricated slab has strong bearing capacity; meanwhile, the weight of the precast slab can be reduced by the precast slab with a hollow inner part, and when the weather is hot in summer, a space is reserved for physical expansion such as expansion with heat and contraction with cold of concrete in the precast slab by the hollow part, so that the bridge deck cannot deform in the using process, and the bridge deck is still flat after the service life reaches a certain degree.
The invention provides a construction method of a municipal bridge precast slab, which comprises the following steps:
the method comprises the following steps: and cutting the first steel bar into three sections according to a certain length, wherein the three sections are respectively the first section of steel bar, the second section of steel bar and the third section of steel bar 25, and the lengths of the first section of steel bar, the second section of steel bar and the third section of steel bar 25 are sequentially decreased progressively.
Step two: the first and second lengths of steel bar are bent into first and second rectangles as the support portions 23. The second rectangle is parallel to the first rectangle inside the opening part of the two ends of the first rectangle and the second rectangle is welded, the welding opening part of the first rectangle and the welding opening part of the second rectangle are staggered and placed, the first rectangle and the second rectangle are prevented from falling off when the welding of the rectangular opening part is not firm, and the first rectangle and the second rectangle are welded and connected through the third section of reinforcing steel bars 25.
Step three: the second reinforcing bar is fixedly connected as an extension 24 at the four corners perpendicular to the first and second rectangles, for example, by welding the second reinforcing bar to the four corners of the first and second rectangles. And supporting parts 23 are uniformly distributed in the length direction of the second reinforcing steel bars, the lifting hooks 3 are vertically fixed on the supporting parts 23, the lifting hooks are welded on the supporting parts, a plurality of lifting hooks can be arranged according to the requirement of actually moving the prefabricated plate, and the lifting hooks are arranged on the supporting parts of the middle reinforcing cages.
Step four: and a layer of diaphragm is paved at the bottom of the mould so that the mould is separated from the precast slab when the precast slab is taken out later. The hollow air bags are placed in the reinforcement cages, a plurality of reinforcement cages with the hollow air bags are uniformly and transversely arranged in the mold, and the number of the reinforcement cages can be properly increased according to the width of the bridge required by actual construction so as to increase the width of the precast slab. And then adding mortar for pouring, vibrating by using a vibrating rod during pouring to compact the mortar, vibrating for 3-5min, and compacting and striking off the surface of the mortar by using a scraper to form a bearing body. In the construction process, the two ends of the hollow air bag are provided with cushion blocks, so that the reinforcing cage is positioned in the middle of the mold in the thickness direction.
Step five: and after 20-30h, taking the load-bearing bodies out of the mold, simultaneously taking out the hollow air bags, sequentially stacking the load-bearing bodies, separating the middle of each load-bearing body by using wood blocks, and intensively watering for maintenance, wherein the maintenance time is 5-6 days.
Step six: checking whether the surface of the bearing body has a crack or is damaged, picking out the bearing body with cracks on the surface, and repairing the crack for use.
Step seven: the bearing bodies are placed on the bridge piers, the connection position of each bearing body is positioned on the bridge piers, and mortar is used for pouring and sealing the connection position of the end parts of the bearing bodies. When the bearing bodies are placed, the connecting parts on the two sides of the bearing bodies are mutually meshed and connected, so that seamless connection between the bearing bodies is realized.
The invention also comprises the following steps for manufacturing the connecting part of the invention:
the method comprises the following steps: when the middle of the bearing body is poured, mortar is tiled on two sides of the mold and vibrated by the vibrating rod, so that the mortar is compact. The purpose of this step is that the mortar of connecting portion is laid to convenient next step lays the reinforcing bar in connecting portion inside, can guarantee to place the third reinforcing bar above being located the centre of connecting portion after the bedding of a layer of mortar, and the reinforcing bar is located the intermediate position when connecting portion atress, makes connecting portion even atress be difficult to appear damaging.
Step two: uniformly placing a plurality of third reinforcing steel bars on the dense mortar on the two sides; and putting a third reinforcing steel bar to enhance the stress of the connecting part.
Step three: and (3) paving mortar on the third reinforcing bar, vibrating by using a vibrating rod to compact the mortar, compacting and strickling the surface of the mortar by using a scraper after vibrating for 3-5min, and finishing the pouring of the connecting part. A layer of mortar is densely paved on the third reinforcing steel bar, so that the thickness of the connecting part is ensured, and meanwhile, the third reinforcing steel bar can be firmly poured into the connecting part, and the bearing capacity of the connecting part is ensured.
Step four: during installation, the connecting parts on the two sides of the bearing plate are mutually attached and installed. The connecting portions on the two sides are respectively positioned at the upper end and the lower end, the height after the attachment is equivalent to the thickness of the bearing body, and the bearing bodies are guaranteed to be connected smoothly and seamlessly.
The diameter of the second reinforcing steel bar is 2-3 times of the diameter of the first reinforcing steel bar during construction. When the thickness of the bearing plate is higher than 50cm, the two layers of reinforcing cages can be overlapped, and the distance between the reinforcing cages in the vertical direction is more than 10 cm.
The prefabricated slab provided by the invention has the following three outstanding beneficial effects: 1. the reinforcing cage is designed into a rectangular structure, and the four corners of the reinforcing cage are uniformly stressed and are not easy to deform during operation of reinforcing steel bars, so that the bearing capacity of the bearing plate is guaranteed. Furthermore, the reinforcing cage in the bearing plate is formed by welding two layers of steel bars to increase the bearing capacity of the reinforcing cage, the inner diameter of the reinforcing cage can be selected, mortar can be filled between the first reinforcing cage and the second reinforcing cage when the hollow part in the reinforcing cage is poured, and the firmness degree between the steel bars and the mortar is greatly enhanced. 2. The reinforcing cage is hollow inside, and a hollow air bag is filled in the second reinforcing cage during pouring, so that the manufactured bearing body contains a through hole, the weight of the bearing body is reduced, and the production cost is saved. 3. The connecting parts at the two sides of the bearing body can ensure that each bearing plate is tightly and seamlessly connected, the steel bars are poured in the connecting parts, meanwhile, the bearing capacity of the connecting parts is equivalent to that of other parts of the bearing plates, the bridge prefabricated plates are seamlessly connected, and the whole bridge prefabricated plate is uniformly stressed after being installed. 4. The through holes in the bearing bodies and the reserved height between the connecting parts enable the prefabricated plates to provide expansion deformation space when the natural gas inflammation heat materials are expanded in the use process after the prefabricated plates are installed, the prefabricated plates are prevented from deforming, and the bridge deck is guaranteed to be flat and not prone to deformation.
The above embodiments are only for illustrating the invention and are not to be construed as limiting the invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention, therefore, all equivalent technical solutions also belong to the scope of the invention, and the scope of the invention is defined by the claims.