Cable-stayed bridge deck crane for hoisting large-tonnage cable-stayed bridge steel beam and construction method

Abstract

The invention provides a cable-stayed bridge deck crane for hoisting a large-tonnage cable-stayed bridge steel beam and a construction method, two cable-stayed devices are respectively arranged on two sides of the front end of each main truss of the cable-stayed bridge deck crane, each cable-stayed device comprises two lug plates, an anchoring plate and a tensioning jack, the two lug plates are respectively welded on the top of the main truss, and the anchoring plate is welded on the top of the main truss. The anchor pulling plate comprises two side plates, the front ends of the two side plates are hinged to the two lug plates respectively, a counter-force plate is fixedly connected between the rear ends of the two side plates, the tensioning jack is arranged between the two side plates and supported on the inner side of the counter-force plate, a temporary inhaul cable is connected between each cable pulling device and a cable tower of the cable-stayed bridge, one end of the temporary inhaul cable is anchored to the top of the cable tower of the cable-stayed bridge, and the other end of the temporary inhaul cable is anchored to the top of the cable tower of the cable-stayed bridge. The other end of the tensioning rod penetrates through the counter-force plate and is connected with the tensioning jack; when the bridge deck crane hoists the steel beam of the cable-stayed bridge, the tensioning jack provides reverse tension for the front end of the bridge deck crane by tensioning the temporary inhaul cable. The rated hoisting weight of the bridge deck crane can be increased, the construction safety is guaranteed, and the construction efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge construction, relates to the hoisting construction of cable-stayed bridge steel beams, and specifically relates to a cable-stayed bridge deck crane and a construction method for hoisting large-tonnage cable-stayed bridge steel beams. Background Art

[0002] Cable-stayed bridge steel beams are often hoisted using bridge deck cranes. Figure 1 The figure shows a commonly used bridge crane and a schematic diagram of its construction status, the bridge crane includes a diamond-shaped main truss 1, a rear anchor point is set at the rear end of the lower chord of the main truss, and the rear anchor point is temporarily anchored on the installed beam segment 100 through the anchor screw 2, the front end of the lower chord of the main truss is supported on the top of the front end of the beam segment through the front support 3, and a lifting jack 4 is set at the front end of the top of the upper chord of the main truss. The lifting jack 4 is connected to the lifting device 6 through the steel strand 5, and the lifting device 6 is connected to the beam segment 101 to be installed. The beam segment to be installed is lifted to the installation position by the lifting jack and docked with the installed beam segment, and the inclined cable 200 is installed to complete the lifting of one beam segment, then the anchoring of the rear anchor point is released, the bridge crane is moved forward by the distance of one beam segment, and after re-anchoring with the installed beam segment, the next beam segment is lifted, and the construction is circulated in this way.

[0003] It can be seen from the above existing bridge crane structure and construction method that the lifting capacity of the bridge crane mainly depends on the anchor strength of the rear anchor point and the structural strength of the main truss itself. Its rated lifting capacity is limited. When lifting large-tonnage cable-stayed bridge steel beams, the following problems exist:

[0004] 1. With the increase of steel beam lifting weight, in order to improve the lifting capacity of bridge cranes, it is often necessary to develop special bridge cranes and strengthen the main truss structure. For example, a thousand-ton double-main-truss bridge crane is large in size, high in cost, and heavy in weight, which has an adverse effect on the bridge line shape and is limited in application and promotion;

[0005] 2. For the hoisting of large-tonnage steel beams, if the anchoring force at the rear anchor point is insufficient, there is a risk of the bridge crane overturning. It is necessary to add a large amount of counterweight at the rear anchor point, and the construction guarantee measures are complicated;

[0006] 3. For the erection of steel-concrete composite beams, the weight of a single beam section is large. In order to control the lifting weight, batch lifting is generally selected, that is, the steel beam is lifted first and then the bridge deck is installed. Compared with the overall lifting, one construction process is added. In addition, since the bridge crane occupies the installation position of the bridge deck, the bridge deck can only be installed from the back after the bridge crane moves forward, which reduces the construction efficiency;

[0007] 4. The front fulcrum of the bridge crane is supported at the front end of the steel beam segment, which can easily cause the steel beam to sag and deform at the front fulcrum. In actual construction, the front fulcrum needs to be specially reinforced, or the deformation of the joint needs to be dealt with before the beam segment is spliced, which affects construction efficiency. Summary of the invention

[0008] The purpose of the present invention is to provide a cable-stayed bridge crane and a construction method for lifting steel beams of a large-tonnage cable-stayed bridge, so as to solve the above problems.

[0009] The present invention provides a cable-type bridge crane for lifting steel beams of a large-tonnage cable-stayed bridge, comprising two main trusses, which are respectively arranged on both sides of the top surface of the installed steel beam section of the cable-stayed bridge, and the two main trusses are connected by an upper crossbeam, and a rear anchor point is arranged at the bottom rear end of each main truss, and the rear anchor point is temporarily anchored to the installed beam section of the cable-stayed bridge through an anchoring screw, and a front fulcrum is arranged at the bottom front end of each main truss, and the front fulcrum is supported on the top surface of the front end of the installed beam section of the cable-stayed bridge, and a lifting jack is arranged in the middle of the top front end of each main truss, which is characterized in that: a set of cable devices is respectively arranged on both sides of the front end of each main truss Each set of cable-pulling device includes two ear plates, an anchor plate and a tensioning jack. The two ear plates are respectively welded to the top of the main truss. The anchor plate is a U-shaped structure, including two side plates. The front ends of the two side plates are respectively hinged to the two ear plates, and a reaction plate is fixedly connected between the rear ends of the two side plates. The tensioning jack is arranged between the two side plates of the U-shaped anchor plate, and the base of the tensioning jack is supported on the inner side of the reaction plate. A temporary cable is connected between each set of cable-pulling device and the cable tower of the cable-stayed bridge. One end of the temporary cable is anchored at the top of the cable tower of the cable-stayed bridge, and the other end passes through the reaction plate and is connected to the tensioning jack.

[0010] The present invention provides a construction method for hoisting steel beams of a large-tonnage cable-stayed bridge, which adopts the above-mentioned guy-cable bridge crane and is characterized in that it comprises the following steps:

[0011] (1) After the steel beam segments of the tower area of ​​the cable-stayed bridge are installed, a cable-stayed bridge crane is installed on the tower area beam segment; the rear anchor point of the bridge crane is temporarily anchored to the steel beam through anchor screws, and a temporary cable is connected between each set of cable-stayed devices on the bridge crane and the cable tower. One end of the temporary cable is anchored to the top of the cable tower, and the other end passes through the reaction plate of the cable-stayed device and is connected to the tensioning jack;

[0012] (2) The two lifting jacks on the bridge crane are connected to the lifting fixtures through steel strands, and the lifting fixtures are connected to the beam section to be installed;

[0013] (3) Synchronously start the two lifting jacks to apply vertical lifting force to the steel beam to be installed, and at the same time start each tensioning jack to apply a certain tensioning force to the temporary cable. After the beam section to be installed is empty, lock the tensioning jacks, and use the lifting jacks to continue lifting the beam section to be installed to the installation position;

[0014] (4) The beam segment to be installed is connected with the installed beam segment, and then the permanent cable stays of the cable-stayed bridge are installed and tensioned to complete the lifting of one beam segment;

[0015] (5) Release the anchorage between the rear anchor point of the bridge crane and the steel beam, and release or loosen the connection between the temporary cable and the tensioning jack; push the bridge crane forward the distance of a beam section, re-anchor the rear anchor point, reconnect the temporary cable and the tensioning jack, and hoist the next beam section according to the method of steps (2) to (4) above, and repeat the construction until all beam sections are hoisted.

[0016] According to a specific embodiment of the present invention, in step (3) of the above-mentioned construction method, the lifting jack applies vertical lifting force to the steel beam to be installed in stages. After each level of vertical lifting force is applied, the main truss structure of the bridge crane is detected and confirmed to be safe, and then the next level of vertical lifting force is applied; the tensioning jack synchronously applies a certain tensioning force to the temporary cable according to the lifting force of each level of the lifting jack, and the tensioning jack is locked after the beam section to be installed is vacated.

[0017] Furthermore, the lifting jack applies vertical lifting force to the steel beam to be installed in 5 levels, and each level of vertical lifting force is 20% of the weight of the beam section to be installed.

[0018] According to a specific embodiment of the present invention, in the above construction method, the tensioning force applied by the tensioning jack to the temporary cable is set in the following manner:

[0019] Assume that the total vertical lifting force of the two lifting jacks is F1, the angle between the temporary cable and the horizontal plane is θ, the total tensioning force applied by each tensioning jack to the temporary cable is T, and the total vertical component of the tensioning force T is T1; T1 = Tsinθ;

[0020] According to the principle of force balance and structural safety of the main truss of the bridge crane, set F1 / 4≤T1≤F1, then:

[0021] (F1 / 4) / sinθ≤T≤F1 / sinθ;

[0022] The cable-stayed bridge crane is equipped with 4 sets of cable-stayed devices and 4 tensioning jacks in total, that is, the tensioning force applied by each tensioning jack to the temporary cable is T / 4.

[0023] The present invention utilizes the structural characteristics of the cable-stayed bridge and innovatively sets a guying device between the front end of the main truss of the bridge deck crane and the main tower of the cable-stayed bridge. Compared with the prior art, it has the following advantages:

[0024] 1. The guy wire device shares part of the vertical force of the lifting load, which increases the rated lifting weight of the bridge crane without increasing the structural weight of the bridge crane. It has outstanding advantages in lifting large-tonnage steel beams and is significantly economical and practical.

[0025] 2. It can reduce the requirements for the anchoring force of the rear anchor point and the supporting force of the front support point of the bridge crane, greatly improve the stress on the bridge deck, and reduce the cost of anchoring and reinforcement;

[0026] 3. The guy cable device transforms the front end area of ​​the traditional bridge crane from a cantilever force-bearing system to a simply supported force-bearing system. The structure is safer, more stable and reliable, and can avoid the risk of overturning of the bridge crane.

[0027] 4. Due to the improved lifting capacity, the steel main beam and bridge deck of the steel-concrete composite beam can be hoisted as a whole, which is conducive to improving construction efficiency and saving construction time. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a side view of the existing bridge crane structure and construction method;

[0029] Figure 2 It is a side view of the structure and construction status of the cable-type bridge deck crane of the present invention;

[0030] Figure 3 It is a front view structural schematic diagram of the cable-type bridge deck crane of the present invention on half of the bridge, and the structure on the other half of the bridge is the same;

[0031] Figure 4 yes Figure 3 Enlarged view of point A in the middle;

[0032] Figure 5 yes Figure 3 II-direction cross-section diagram;

[0033] Figure 6 yes Figure 5 Enlarged view of point B in the middle;

[0034] Figure 7 It is a schematic diagram of the force principle of the cable-type bridge crane of the present invention. DETAILED DESCRIPTION

[0035] like Figures 2 to 6As shown, the present invention provides a cable-type bridge crane for lifting steel beams of a large-tonnage cable-stayed bridge, comprising two main trusses 1, the two main trusses are respectively arranged on both sides of the top surface of the installed steel beam section 100 of the cable-stayed bridge, the two main trusses are connected by an upper crossbeam, a rear anchor point is arranged at the bottom rear end of each main truss, the rear anchor point is temporarily anchored to the installed beam section 100 of the cable-stayed bridge through an anchoring screw 2, a front fulcrum 3 is arranged at the bottom front end of each main truss, the front fulcrum 3 is supported on the top surface of the front end of the installed beam section 100 of the cable-stayed bridge, a lifting jack 4 is arranged in the middle of the top front end of each main truss 1, a set of cable devices 7 are respectively arranged on both sides of the front end of each main truss, and each set of cable devices 7 includes two ear plates, an anchor plate and a tensioning jack. The two ear plates 71 are respectively welded to the top of the main truss 1. The anchor plate is a U-shaped structure, including two side plates 72. The front ends of the two side plates 72 are respectively hinged to the two ear plates 71. A reaction plate 73 is fixedly connected between the rear ends of the two side plates 72. The tensioning jack 74 is arranged between the two side plates 72 of the U-shaped anchor plate. The base of the tensioning jack 74 is supported on the inner side of the reaction plate 73. A temporary cable 8 is connected between each set of cable-stayed bridge towers. One end of the temporary cable 8 is anchored at the top of the tower of the cable-stayed bridge, and the other end passes through the reaction plate 73 and is connected to the tensioning jack 74.

[0036] In the above structure, the tensioning jack 74 can apply a pulling force diagonally upward to the front end of the main truss 1 of the bridge crane by tensioning the temporary cable 8, so as to share part of the vertical load force borne by the front end of the main truss when the bridge crane is hoisted. Since the two side plates 72 of the anchor plate are hinged with the ear plates 71 on the main truss, the anchor plate can automatically adapt to the change of the angle between the temporary cable and the horizontal plane, so that the tensioning direction of the tensioning jack is always consistent with the axial direction of the temporary cable, avoiding cable force loss.

[0037] The force principle of the above-mentioned cable-type bridge crane is as follows: Figure 7 As shown in the figure, the diagonal cable tension provided by the temporary cable is T, and the cable tension T can be decomposed into vertical component T1 and horizontal component T2. The front support point is the balance support point O. The rear anchor point provides vertical tension F2 and horizontal tension F3, and the steel beam lifting weight is F1.

[0038] According to the principle of moment balance, the moment balance formula at the front support O is as follows:

[0039] T 1 *L 1 +F 2 *L 2 =F 1 *L 1

[0040] According to the formula, when the lifting weight F1 is constant, the existence of the cable tension T can reduce the magnitude of the anchoring force F2 of the rear anchor point; when the anchoring force F2 of the rear anchor point remains unchanged, the existence of the cable tension T can increase the lifting weight F1 of the steel beam. In addition, due to the existence of the cable tension T, the reaction force at the front support point will be reduced, thereby reducing the concave deformation at the support point of the steel beam. Therefore, the cable-type bridge crane can effectively improve the stress performance of the steel beam and the main truss structure, and improve the anti-overturning safety factor of the main truss.

[0041] The construction method for hoisting a large-tonnage cable-stayed bridge steel beam using the above-mentioned cable-stayed bridge crane comprises the following steps:

[0042] (1) Figures 2 to 6 As shown, a car crane is first used to hoist the beam section of the cable-stayed bridge tower area onto the lower cross beam of the tower. After the steel beam section of the cable-stayed bridge tower area is installed, a cable-stayed bridge crane is set on the installed beam section; the rear anchor point and the front support point 3 of the main truss 1 of the bridge crane are positioned, and the rear anchor point and the installed steel beam 100 are temporarily anchored by the anchor screw 2. A temporary cable 8 is connected between each set of cable-stayed device 7 on the bridge crane and the tower. One end of the temporary cable is anchored at the top of the tower, and the other end passes through the reaction plate 73 of the cable-stayed device and is connected to the tensioning jack 74;

[0043] (2) transporting the beam section to be installed to the bottom of the bridge; connecting the two lifting jacks 4 on the bridge crane to the lifting device 6 through the steel strands 5, and connecting the lifting device 6 to the beam section 101 to be installed;

[0044] (3) Synchronously start the two lifting jacks 4 to apply a vertical lifting force to the beam section 101 to be installed, and simultaneously start the tensioning jacks 74 to apply a certain tensioning force to the temporary cable 8. After the beam section 101 to be installed is free, lock the tensioning jacks, and continue to lift the beam section to be installed to the installation position with the lifting jacks;

[0045] (4) The beam segment to be installed is connected to the installed beam segment, and then the permanent cable stay cables 200 of the cable-stayed bridge are installed and tensioned to complete the hoisting of one beam segment;

[0046] (5) Release the anchorage between the rear anchor point of the bridge crane and the steel beam, and release or loosen the connection between the temporary cable and the tensioning jack; push the bridge crane forward the distance of a beam section, re-anchor the rear anchor point, reconnect the temporary cable and the tensioning jack, and hoist the next beam section according to the method of steps (2) to (4) above, and repeat the construction until all beam sections are hoisted.

[0047] When the present invention is implemented, in order to ensure construction safety, in step (3) of the above-mentioned construction method, the lifting jack can apply vertical lifting force to the steel beam to be installed in stages. After each level of vertical lifting force is applied, the main truss structure of the bridge crane is detected and confirmed to be safe, and then the next level of vertical lifting force is applied; the tensioning jack synchronously applies a certain tensioning force to the temporary cable according to the lifting force of each level of the lifting jack, and the tensioning jack is locked after the beam section to be installed is vacated.

[0048] When the present invention is implemented, the lifting jack can apply vertical lifting force to the steel beam to be installed in 5 levels, and each level of vertical lifting force is 20% of the weight of the beam section to be installed.

[0049] The tensioning force applied by the tensioning jack to the temporary cable is set in the following manner:

[0050] Assume that the total vertical lifting force of the two lifting jacks is F1, the angle between the temporary cable and the horizontal plane is θ, the total tensioning force applied by each tensioning jack to the temporary cable is T, the total vertical component of the tensioning force T is T1, and the total horizontal component is T2; T1 = Tsinθ, T2 = Tcosθ;

[0051] According to the principle of force balance and structural safety of the main truss of the bridge crane, the value range of T1 can be pre-set by comprehensively considering the total lifting weight of the bridge crane and the angle θ between the temporary cable and the horizontal plane. If the value range of T1 is set to F1 / 4≤T1≤F1, the value range of the total tensioning force T of the tensioning jack can be calculated as:

[0052] (F1 / 4) / sinθ≤T≤F1 / sinθ.

[0053] During specific construction, a certain value can be selected within the value range of T1 according to the on-site working conditions, and then a certain value of T can be calculated and evenly distributed to each tensioning jack. In a specific embodiment of the present invention, the cable-stayed bridge crane is provided with 4 sets of cable-stayed devices and 4 tensioning jacks in total, so the tensioning force applied by each tensioning jack to the temporary cable should be T / 4.

Claims

1. A cable-stayed bridge crane for lifting steel beams of a large-tonnage cable-stayed bridge, comprising two main trusses, which are respectively arranged on both sides of the top surface of the installed steel beam section of the cable-stayed bridge, and the two main trusses are connected by an upper crossbeam, and a rear anchor point is arranged at the bottom rear end of each main truss, and the rear anchor point is temporarily anchored to the installed beam section of the cable-stayed bridge through an anchoring screw, and a front support point is arranged at the bottom front end of each main truss, and the front support point is supported on the top surface of the front end of the installed beam section of the cable-stayed bridge, and a lifting jack is arranged in the middle of the top front end of each main truss, characterized in that: A set of cable pulling devices are respectively provided on both sides of the front end of each main truss, and each set of cable pulling devices includes two ear plates, an anchor plate and a tensioning jack. The two ear plates are respectively welded to the top of the main truss. The anchor plate is a U-shaped structure, including two side plates. The front ends of the two side plates are respectively hinged to the two ear plates, and a reaction plate is fixedly connected between the rear ends of the two side plates. The tensioning jack is arranged between the two side plates of the U-shaped anchor plate, and the base of the tensioning jack is supported on the inner side of the reaction plate. A temporary cable is connected between each set of cable pulling devices and the cable tower of the cable-stayed bridge. One end of the temporary cable is anchored at the top of the cable tower of the cable-stayed bridge, and the other end passes through the reaction plate and is connected to the tensioning jack.

2. A construction method for hoisting steel beams of a large-tonnage cable-stayed bridge, using the guyed bridge crane according to claim 1, characterized in that: The following steps are involved: (1) After the steel beam segments of the tower area of ​​the cable-stayed bridge are installed, a cable-stayed bridge crane is installed on the tower area beam segment; the rear anchor point of the bridge crane is temporarily anchored to the steel beam through anchor screws, and a temporary cable is connected between each set of cable-stayed devices on the bridge crane and the cable tower. One end of the temporary cable is anchored to the top of the cable tower, and the other end passes through the reaction plate of the cable-stayed device and is connected to the tensioning jack; (2) The two lifting jacks on the bridge crane are connected to the lifting fixtures through steel strands, and the lifting fixtures are connected to the beam section to be installed; (3) Synchronously start the two lifting jacks to apply vertical lifting force to the steel beam to be installed, and at the same time start each tensioning jack to apply a certain tensioning force to the temporary cable. After the beam section to be installed is empty, lock the tensioning jacks, and use the lifting jacks to continue lifting the beam section to be installed to the installation position; (4) The beam segment to be installed is connected with the installed beam segment, and then the permanent cable stays of the cable-stayed bridge are installed and tensioned to complete the lifting of one beam segment; (5) Release the anchorage between the rear anchor point of the bridge crane and the steel beam, and release or loosen the connection between the temporary cable and the tensioning jack; push the bridge crane forward the distance of a beam section, re-anchor the rear anchor point, reconnect the temporary cable and the tensioning jack, and hoist the next beam section according to the method of steps (2) to (4) above, and repeat the construction until all beam sections are hoisted.

3. The construction method for hoisting steel beams of a large-tonnage cable-stayed bridge according to claim 2 is characterized in that: In the step (3), the lifting jack applies vertical lifting force to the steel beam to be installed in stages. After each level of vertical lifting force is applied, the main truss structure of the bridge crane is tested and confirmed to be safe before the next level of vertical lifting force is applied. The tensioning jack applies a certain tensioning force to the temporary cable synchronously according to the lifting force of each level of the lifting jack, and the tensioning jack is locked after the beam section to be installed is empty.

4. The construction method for hoisting steel beams of a large-tonnage cable-stayed bridge according to claim 3 is characterized in that: The lifting jack applies vertical lifting force to the steel beam to be installed in 5 levels, and each level of vertical lifting force is 20% of the weight of the beam section to be installed.

5. The construction method for hoisting steel beams of a large-tonnage cable-stayed bridge according to claims 2 to 4 is characterized in that: The tensioning force applied by the tensioning jack to the temporary cable is set in the following manner: Assume that the total vertical lifting force of the two lifting jacks is F1, the angle between the temporary cable and the horizontal plane is θ, the total tensioning force applied by each tensioning jack to the temporary cable is T, and the total vertical component of the tensioning force T is T1; T1 = Tsinθ; According to the principle of force balance and structural safety of the main truss of the bridge crane, set F1 / 4≤T1≤F1, then: (F1 / 4) / sinθ≤T≤F1 / sinθ; The cable-stayed bridge crane is equipped with 4 sets of cable-stayed devices and 4 tensioning jacks in total, that is, the tensioning force applied by each tensioning jack to the temporary cable is T / 4.

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