Crack Resistance Methods for Steel-Concrete Composite Beam Ramp Bridges

Abstract

This invention discloses a crack-resistant method for a steel-concrete composite beam ramp bridge, comprising the following steps: S1, prefabricating steel beams in a factory according to design drawings and transporting them to the site, then installing the steel beams on the bridge piers; S2, dividing the bridge deck into a positive bending moment region, a negative bending moment region, and a region above the piers on both sides, laying formwork for the positive bending moment region and the region above the piers on the steel beams, pouring concrete, curing, and removing the formwork after the bridge deck strength meets the specifications; S3, laying formwork for the negative bending moment region on the steel beams, pouring concrete, curing, and removing the formwork after the bridge deck strength meets the specifications. This invention can effectively improve the crack resistance of the concrete bridge deck in the negative bending moment region of the steel-concrete composite beam, and subsequent operations are convenient after one construction is completed.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering technology. More specifically, this invention relates to a crack-resistant method for steel-concrete composite beam ramp bridges. Background Technology

[0002] Steel-concrete composite continuous beams are a new type of structural form that has been developed in recent years and has been applied to a certain extent both domestically and internationally. The use of steel and PC concrete composite continuous beam systems not only effectively reduces self-weight and enhances the spanning capacity of continuous beam bridges, but also significantly reduces construction time constraints when crossing highways and railway lines, minimizing the risk of accidents and improving production efficiency. While the steel-concrete composite beam structure system has many advantages, it also has disadvantages: because the middle pier is a negative bending moment zone, the concrete bridge deck is pushed upwards by the supports, causing the concrete bridge deck on both sides to bend downwards. This makes the concrete bridge deck in this area prone to cracking, and over time, it will cause corrosion of the internal steel reinforcement, affecting the service life of the steel-concrete composite beam. Summary of the Invention

[0003] The purpose of this invention is to provide a crack-resistant method for steel-concrete composite beam ramp bridges, which can effectively improve the crack resistance of the concrete bridge deck in the negative bending moment area of ​​the steel-concrete composite beam, and facilitates subsequent operations after one construction is completed.

[0004] The technical solution adopted by this invention to solve this technical problem is: a crack-resistant method for steel-concrete composite beam ramp bridges, comprising the following steps:

[0005] S1. According to the design drawings, prefabricate the steel beams in the factory and transport them to the site, then install the steel beams on the bridge piers;

[0006] S2. Divide the bridge deck into a positive bending moment area, a negative bending moment area, and an area above the piers on both sides. Lay the formwork for the positive bending moment area and the area above the piers on the steel beam, pour concrete, and cure it. After the bridge deck strength reaches the specification requirements, remove the formwork.

[0007] S3. Lay the negative bending moment area formwork on the steel beam, pour concrete, and cure it. After the bridge deck strength reaches the specification requirements, remove the formwork.

[0008] Preferably, in S1, a support is installed on the bridge pier, and the steel beam is hoisted and installed on the support.

[0009] Preferably, the positive bending moment region is the middle part between the two piers, and the negative bending moment region is the area above and on both sides of the middle pier.

[0010] Preferably, in step S2, shear studs are welded onto the steel beams in the positive bending moment region, and then the studs are cast into the concrete bridge deck in the positive bending moment region by concrete pouring.

[0011] Preferably, the bridge deck in the negative bending moment region in step S3 includes: a concrete structure, a reinforcing cage, and a tension assembly replacing the bottom reinforcing bars; the reinforcing cage is placed above the tension assembly and then cast into a whole by concrete pouring;

[0012] The tension assembly includes a main drive steel rod, several driven worm gears, a rubber sleeve, and a steel sleeve;

[0013] The main drive steel rod extends transversely along the bridge deck and is located at the bottom of the bridge deck in the negative bending moment region. Multiple gears are spaced apart on the active drive steel rod. Multiple worm gears mesh with the gears in a one-to-one correspondence. The worm gears extend longitudinally along the bridge deck. The steel sleeve includes an upper steel sleeve and a lower steel sleeve. Both ends of the worm gear are fixed to the lower steel sleeve via bearings and bearing seats. Steel wire ropes are spaced apart on the worm gear and wound around it. The upper steel sleeve covers and is fixed to the lower steel sleeve, isolating the main drive steel rod and driven worm gear from the concrete of the bridge deck. A through hole is formed on the upper steel sleeve, which is connected to the bottom reinforcing bars of the reinforcing cage via a rubber sleeve. The steel wire rope is fixed to the bottom of the reinforcing cage. The steel sleeve is located at one end of the main drive steel rod and on the bridge deck extending from the main drive steel rod into the negative bending moment region. The extended end of the active drive steel rod is driven to rotate by a drive device.

[0014] Preferably, a pressure sensor is installed on the pier support located in the middle part to monitor the force between the steel beam and the support. The pressure sensor and the driving device are both connected to the PLC controller.

[0015] The PLC controller is configured to control the drive device to rotate when the pressure value detected by the pressure sensor is greater than a set threshold, thereby tightening the wire rope to a set tension through the rotation of the driven worm gear.

[0016] The present invention has at least the following beneficial effects: the crack resistance method for steel-concrete composite beam ramp bridge can effectively improve the crack resistance performance of the concrete bridge deck in the negative bending moment area of ​​the steel-concrete composite beam, and subsequent operations are convenient after one construction is completed.

[0017] By monitoring the stress changes in the negative bending moment area in real time using pressure sensors, the stress on the concrete bridge deck can be adjusted in a timely manner. Tension components are pre-embedded in the concrete bridge deck in the negative bending moment area. When the pressure monitored by the pressure sensor exceeds the set threshold, the steel wire rope is wound through the drive device and transmission component. When the steel wire rope is wound on the driven worm, it causes the reinforcing cage to be subjected to downward force. The downward force of the reinforcing cage counteracts the force transmitted from the top of the support, reducing the stress on the concrete and thus achieving the purpose of crack resistance.

[0018] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0019] Figure 1 This is a structural schematic diagram of the steel-concrete composite beam of the present invention;

[0020] Figure 2 This is a schematic diagram of the bridge deck structure in the negative bending moment region of the present invention;

[0021] Figure 3 This is a top view of the tension component of the present invention.

[0022] Explanation of reference numerals in the attached drawings: 1 steel beam, 2 pier, 3 bearing, 4 bridge deck in the positive bending moment zone, 5 bridge deck in the negative bending moment zone, 6 reinforcing cage, 7 wire rope, 8 gear, 9 main drive steel rod, 10 driven worm gear, 11 rubber sleeve, 12 lower steel sleeve, 13 drive device, 14 bearing seat. Detailed Implementation

[0023] The present invention will now be described in detail and completely with reference to the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention with reference to the accompanying drawings, it should be particularly noted that the technical solutions and features provided in various parts of the present invention, including the following description, can be combined with each other without conflict.

[0024] Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific implementation process is as follows:

[0026] like Figures 1-3 As shown, the present invention provides a crack-resistant method for a steel-concrete composite beam ramp bridge, comprising the following steps:

[0027] S1. According to the design drawings, steel beam 1 is prefabricated in the factory and transported to the site, and steel beam 1 is installed on the bridge pier 2;

[0028] S2. Divide the bridge deck into a positive bending moment area bridge deck 4, a negative bending moment area bridge deck 5, and the area above the piers 2 on both sides. Lay the formwork for the positive bending moment area and the area above the piers 2 on the steel beam 1. The area above the piers 2 on both sides can be formwork erected together with the positive bending moment area on that side, and concrete is poured and cured. After the bridge deck strength reaches the specification requirements, the formwork is removed.

[0029] S3. Lay the negative bending moment area formwork on steel beam 1, pour concrete, and cure it. After the bridge deck strength reaches the specification requirements, remove the formwork.

[0030] This technical solution may also include the following technical details to better achieve the technical effect: a support 3 is installed on the pier 2 in S1, and the steel beam 1 is hoisted and installed on the support 3.

[0031] This technical solution may also include the following technical details to better achieve the technical effect: the positive bending moment region is the middle part between the two bridge piers 2, and the negative bending moment region is the area above and on both sides of the middle bridge pier 2.

[0032] This technical solution may also include the following technical details to better achieve the technical effect: In S2, shear studs are welded on the steel beam 1 in the positive bending moment region, and then cast into the concrete bridge deck in the positive bending moment region by concrete pouring.

[0033] This technical solution may also include the following technical details to better achieve the technical effect:

[0034] The bridge deck in the negative bending moment region in step S3 includes: a concrete structure, a steel cage 6, and a tension component that replaces the bottom steel reinforcement; the steel cage 6 is placed above the tension component and then cast into a whole by concrete pouring; the bottom of the steel cage 6 forms a concave groove during binding to accommodate the tension component.

[0035] The tension assembly includes a main drive steel rod 9, several driven worm gears 10, a rubber sleeve 11, and a steel sleeve;

[0036] The main drive steel rod 9 extends along the transverse direction of the bridge and is located at the bottom of the bridge deck in the negative bending moment region. Multiple gears 8 are spaced apart on the main drive steel rod. Multiple worm gears mesh with the multiple gears 8 in a one-to-one correspondence. The worm gears extend along the longitudinal direction of the bridge. The steel sleeve includes an upper steel sleeve and a lower steel sleeve 12. Both ends of the worm gear are fixed to the lower steel sleeve 12 by bearings and bearing seats 14. Steel wire ropes 7 are spaced apart on the worm gear and are wound around it. The upper steel sleeve covers and fixes itself to the lower steel sleeve 12. The main drive steel rod 9 is driven by the steel sleeve. The transmission steel rod 9 and the driven worm gear 10 are isolated from the concrete of the bridge deck. The upper steel sleeve has a through hole, which is connected to the bottom steel bar of the steel cage 6 through a rubber sleeve 11. The upper end of the rubber sleeve 11 is seamlessly connected to the steel cage 6, and the lower end of the rubber sleeve 11 is seamlessly connected to the through hole. The wire rope 7 is fixed to the bottom of the steel cage 6. The steel sleeve is located at one end of the main transmission steel rod 9 and the bridge deck where the main transmission steel rod 9 extends into the negative bending moment region. The extended end of the active transmission steel rod is driven to rotate by the drive device 13.

[0037] The construction method for the bridge deck in the negative bending moment region includes:

[0038] S31. Install the bottom mold;

[0039] S32. Install the lower steel sleeve 12 directly above each intermediate pier 2, then install the main drive steel rod 9 and several driven worm gears 10, and wind the wire rope 7 around the worm gear at the designed position; place the upper steel sleeve on the lower steel sleeve 12 and pass the wire rope 7 through the through hole. After alignment, weld the upper steel sleeve and the lower steel sleeve 12 into a whole. Then install the rubber sleeve 11 at the through hole, lower the reinforcing cage 6, fix the wire rope 7 to the bottom of the reinforcing cage 6, and fix the rubber sleeve 11 to the through hole and the reinforcing cage 6 with adhesive.

[0040] S32. Install the remaining templates and connect the main drive steel rod 9 to the drive device 13 and make it work. The steel wire rope 7 is kept in a taut state by the rotation of the driven worm gear 10. It is fine as long as it is not in a slack state.

[0041] S33. Pour concrete and cure it. After the bridge deck strength reaches the specification requirements, remove the formwork.

[0042] In the above technical solution, the stress change in the negative bending moment area is monitored in real time by a pressure sensor, and the stress on the concrete bridge deck is adjusted in a timely manner. Tension components are pre-embedded in the concrete bridge deck in the negative bending moment area. When the pressure monitored by the pressure sensor is greater than the set threshold, the wire rope 7 is wound by the drive device 13 and the transmission component. When the wire rope 7 is wound on the driven worm gear 10, the reinforcing cage 6 is subjected to downward force. The downward force of the reinforcing cage 6 offsets the force transmitted from the support 3, reducing the stress on the concrete and thus achieving the purpose of crack resistance.

[0043] This technical solution may also include the following technical details to better achieve the technical effect: a pressure sensor is installed on the support 3 of the pier 2 located in the middle part to monitor the force between the steel beam 1 and the support 3. The pressure sensor and the drive device 13 are both connected to the PLC controller.

[0044] The PLC controller is configured to control the drive device 13 to rotate when the pressure value detected by the pressure sensor exceeds a set threshold. This rotation of the driven worm gear 10 tightens the wire rope 7 to the set tension. The PLC controller enables automated adjustment, eliminating the need for manual adjustment, reducing the difficulty of adjustment, and allowing for dynamic real-time adjustment.

[0045] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A crack-resistant method for a steel-concrete composite beam ramp bridge, characterized in that, Includes the following steps: S1. According to the design drawings, prefabricate the steel beams in the factory and transport them to the site. Install the steel beams on the bridge piers. The bridge piers are equipped with supports. Hoist the steel beams onto the supports. S2. Divide the bridge deck into a positive bending moment region, a negative bending moment region, and a region above the piers on both sides. The positive bending moment region is the middle part between the two piers, and the negative bending moment region is the region above the middle pier and the regions on both sides. Weld shear studs to the steel beams in the positive bending moment region, and pour concrete into the concrete bridge deck in the positive bending moment region. Lay the formwork for the positive bending moment region and the region above the piers on the steel beams, pour concrete, and cure. After the bridge deck strength reaches the specification requirements, remove the formwork. S3. Lay the negative bending moment area formwork on the steel beam, pour concrete, and cure it. After the bridge deck strength reaches the specification requirements, remove the formwork. The bridge deck in the negative bending moment region includes a concrete structure, a steel cage, and a tension assembly that replaces the bottom steel reinforcement. The steel cage is positioned above the tension assembly and is then cast into a single unit by concrete pouring. The tension assembly includes a main drive steel rod, several driven worm gears, a rubber sleeve, and a steel sleeve; The main drive steel rod extends transversely along the bridge deck and is located at the bottom of the bridge deck in the negative bending moment region. Multiple gears are spaced apart on the main drive steel rod. Multiple worm gears mesh with the gears in a one-to-one correspondence. The worm gears extend longitudinally along the bridge deck. The steel sleeve includes an upper steel sleeve and a lower steel sleeve. Both ends of the worm gear are fixed to the lower steel sleeve via bearings and bearing seats. Steel wire ropes are spaced apart on the worm gear and wound around it. The upper steel sleeve covers and is fixed to the lower steel sleeve, isolating the main drive steel rod and driven worm gear from the concrete of the bridge deck. A through hole is provided on the upper steel sleeve, which is connected to the bottom reinforcing bars of the reinforcing cage via a rubber sleeve. The steel wire ropes are fixed to the bottom of the reinforcing cage. The steel sleeve is located at one end of the main drive steel rod and on the bridge deck where the main drive steel rod extends into the negative bending moment region. The extended end of the main drive steel rod is driven to rotate by a driving device. Meanwhile, a pressure sensor is installed on the pier support in the middle section to monitor the force between the steel beam and the support. The pressure sensor and the drive device are both connected to the PLC controller. The PLC controller is set to control the drive device to rotate when the pressure value detected by the pressure sensor is greater than a set threshold, thereby tightening the wire rope to the set tension through the rotation of the driven worm gear.

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