Large-span beam arch combined bridge top pushing and guiding beam device and construction method

Abstract

The invention relates to a large-span beam-arch combined bridge top guide beam guiding device which comprises a beam-arch combined bridge and a rigidity-variable guide beam fixedly connected with the front end of the beam-arch combined bridge. The guide beam sequentially comprises a high-rigidity double-H-shaped truss section, a tie bar, a cross beam and an end cross beam from the root part to the end part; the cable-stayed device is arranged above the guide beam; the pull-down point is arranged at the lower edge of the front end of the guide beam; the cable-stayed device is connected with the pull-down point through a steel wire rope and used for lifting the end of the guide beam to the designed elevation of the pier top at a time in the pushing process. The self weight of the guide beam is reduced, smooth upsetting in the advancing direction of the bridge body is guaranteed, and the guide beam is prevented from generating large downwarping under the cantilever working condition. The construction precision is ensured, and the efficiency and safety of walking pushing advancing are improved.

Description

Technical Field

[0001] The present invention relates to the field of building construction, in particular to a top guide beam device for a large-span beam-arch combination bridge and a construction method. Background Art

[0002] With the acceleration of my country's urbanization process, the scale and complexity of urban bridge construction have increased significantly. Steel bridges, with their large spans, diverse shapes, short construction periods, and excellent mechanical properties, have become a dominant force in urban bridge construction. However, the complex and ever-changing environment of urban bridge construction requires both ensuring normal river navigation during construction and minimizing the impact on traffic under the bridge, placing higher demands on bridge construction technology. The jacking and dragging construction method has gradually become one of the mainstream technologies in contemporary bridge construction due to its advantages such as small site occupation, minimal interference with traffic under the bridge, simple equipment requirements, high construction safety, and significant cost-effectiveness.

[0003] Over the past decade, steel-concrete composite beams, corrugated steel web beams, and beam-arch systems have been widely used in urban river and line bridges. To minimize disruption to waterways and ground traffic, the push-and-pull method has become the preferred method. This method utilizes the limited length of the assembly site to assemble the main beams segment by segment. The entire span or span is then horizontally slid to the designed position using walking jacks or continuous jacks.

[0004] However, when the span exceeds 80 meters and the bridge width exceeds 20 meters, the guide beam length often needs to reach 0.55 to 0.65 times the main span to keep the construction negative bending moment within the allowable range of the main beam. This extremely long guide beam's maximum cantilever condition becomes the most unfavorable condition during the entire construction process. In large-span beam-arch composite bridges constructed by jacking (or dragging), the front end of the guide beam must remain in the "maximum cantilever" state for a long period of time. During this period, the guide beam's deadweight and the load on the front section of the bridge generate a significant negative bending moment at the guide beam's base, resulting in uncontrollable deflection at the front end (measured maximums of 1 / 250 to 1 / 200 of the span). Once this deflection exceeds the pier support top elevation, the bridge cannot be smoothly placed on the piers, necessitating construction halts and repeated jacking, beam removal, and slope adjustments at the pier tops, delaying construction and increasing the risk of working at height.

[0005] Current guide beam design method 2.1 Solid steel plate girder or steel box girder Advantages: simple production and high overall rigidity.

[0006] Disadvantages: The high web and thick flange result in a unit length mass of 6 to 10 kN / m, greatly increasing the thrust reaction force and the slideway pressure; In order to meet the transportation limits, secondary splicing is often required on site, which requires a lot of welding work; The cross-section is fixed, and the stiffness cannot be “distributed as needed” according to the bending moment envelope diagram, resulting in low material utilization.

[0007] 2.2 Uniform cross-section plane / space truss guide beam Advantages: Light weight (about 60% of a solid beam with the same stiffness).

[0008] Disadvantages: The bending moment of the front cantilever section is small, but the cross-section of the rod is the same as that of the root, resulting in "excessive redundancy"; The number of gusset plates and high-strength bolts is huge, and the installation period is long; The truss web is mainly under compression in the negative bending moment area, and the stability problem is prominent. Usually, a transverse connection system is required to further increase the deadweight.

[0009] 2.3 Multi-point support auxiliary pier During the continuous beam pushing process, temporary auxiliary piers or floating cranes are sometimes set up at the maximum cantilever end to "support" the bridge. However, due to the high navigation level of urban rivers, the placement of temporary piers and floating cranes is often rejected by maritime and waterway departments. If there is an existing railway or elevated road under the bridge span, they cannot be deployed at all.

[0010] 2.4 Prestressed bottom chord or external cable Some projects have attempted to tension temporary external cables on the lower chord of the guide beam to provide a counter-bending moment. However, the external cable anchorage must be located on the already-installed bridge structure, and since the bridge structure has not yet reached the piers, the cable force path cannot be established. If the anchorage is moved forward to the front of the guide beam, the cable force will generate additional axial compression within the guide beam, increasing the risk of buckling. Summary of the Invention

[0011] The present invention aims to overcome the defects of the prior art and provide a large-span beam-arch composite bridge top guide beam device and construction method, which solves the problems of the guide beam deflecting under the maximum cantilever working condition and guiding the bridge body to be smoothly erected.

[0012] In order to solve the above-mentioned technical problems, the present invention is achieved as follows: A long-span beam-arch composite bridge top derivation beam device, characterized in that it comprises: A beam-arch composite bridge and a variable stiffness guide beam fixed to its front end; The guide beam is composed of: high-rigidity double H-shaped truss section, tie rod, cross beam, and end cross beam from the root to the end; It also includes an oblique pulling device installed above the guide beam and a pull-down point located at the lower edge of the front end of the guide beam; The inclined-stayed device is connected to the lowering point via a steel wire rope and is used to lift the end of the guide beam to the designed elevation of the pier top at one time during the jacking process.

[0013] The described large-span beam-arch composite bridge top derivation beam device is characterized in that the high-rigidity double H-shaped truss segment is composed of two vertically arranged H-shaped steel chords and multiple H-shaped steel webs to form a hollow truss, and the two trusses are connected by a tie rod to form a whole.

[0014] The described large-span beam-arch composite bridge top derivation beam device is characterized in that the tie rod is a round tube, and its two ends are directly welded to the corresponding nodes of the two trusses after being cut through the intersection line, so as to eliminate the node plate and reduce the weight.

[0015] The described large-span beam-arch combined bridge top derivation beam device is characterized in that the crossbeam is a triangular tube truss composed of circular tubes, which is arranged at intervals along the longitudinal direction of the guide beam, and the left and right trusses are horizontally connected to form a closed space truss.

[0016] The described large-span beam-arch combined bridge top derivation beam device is characterized in that the end cross beam is a sheet-like tube truss composed of round tubes, which also serves as the installation base of the pull-down point.

[0017] The described large-span beam-arch combined bridge top guide beam device is characterized in that: the inclined-stayed device includes a fixed base, a counterweight block, a winch group, a fixed pulley, a movable pulley, and a steel wire rope; the fixed base is welded to the upper chord of the guide beam, the movable pulley and the fixed pulley form a 2-rate pulley group, one end of the steel wire rope is connected to the winch, and the other end is anchored at the pulley group after passing through the pulley group.

[0018] The device for pushing the guide beam at the top of a large-span beam-arch combined bridge is characterized in that the counterweight block and the winch are arranged together on a fixed base to balance the winch reaction force and simultaneously reduce the negative bending moment at the root of the guide beam.

[0019] The device for pushing the guide beam on the top of a large-span beam-arch combination bridge is characterized in that the guide beam and the beam-arch combination bridge are fixedly connected by a first-level full-penetration weld, and the weld length is not less than 1.5 times the height of the guide beam root.

[0020] The construction method of the long-span beam-arch composite bridge top derivation beam device is characterized in that it includes: S1 Assemble high-rigidity double H-shaped truss segments, tie rods, cross beams, and end cross beams into an integral guide beam at the assembly site and weld them together with the beam-arch combination bridge; S2 Install the inclined pull device to make the wire rope taut but with zero force; S3 starts the walking-type pushing device to move the combined bridge and the guide beam forward synchronously; S4 When the front end of the guide beam approaches the pier, the end of the guide beam is lifted to the designed elevation of the pier top at one time by retracting the rope with the winch; S5 Continue pushing until the beam-arch combination bridge is fully in place, and remove the guide beam and cable-stayed device for recycling.

[0021] The beneficial effects of the present application are: through the above technical scheme, the application provides a large-span beam-arch combined bridge pushing derivation beam device and construction method, the derivation beam is designed as a "variable rigidity, variable cross-section" structure of a root high-rigidity double-H truss section, a middle section circular tube transition truss section, a front section light sheet truss section and an end beam section, high-strength and high-moment of inertia H-shaped steel is only used in the area where the bending moment demand is large, and a circular tube light rod is used in the area where the bending moment rapidly decays. Compared with the traditional solid web steel plate beam or the equal cross-section truss derivation beam of the same span, the overall steel consumption can be reduced by about 40%. The self-weight reduction directly reduces the reaction force demand of the walking pushing jack, and also reduces the bearing requirement of the slide and the temporary pier foundation, thereby saving the steel, concrete and foundation treatment costs.

[0022] The fixed base, winch and pulley block of the cable-stayed device are all integrated on the top chord of the derivation beam, which is spatially separated from the walking jack and the slide system and does not interfere with each other; the counterweight serves as a counterbalance to eliminate the influence of the winch reaction force on the temporary structure. All components use bolted and welded hybrid joints, which can be installed at once in the assembly site, and only one operator is needed to remotely control the winch on the bridge deck platform during the pushing process, avoiding frequent operations of personnel on the pier top or in the waterway at high altitude, and the safety risk is significantly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0023] The present application will be further described in detail below in combination with the drawings and embodiments: Figure 1 is a front view of the beam-arch combined bridge and the derivation beam device; Figure 2 is a plan view of the derivation beam structure; Figure 3 is Figure 2 is a schematic view in the direction of A-A; Figure 4 is Figure 2 is a schematic view in the direction of B-B; Figure 5 is Figure 2 is a schematic view in the direction of C-C; Figure 6 is a structure diagram of the cable-stayed device. DETAILED DESCRIPTION

[0024] The technical solutions of the embodiments of the present application will be described clearly and completely below in combination with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application. As Figure 1-6As shown: A top guide beam device for a large-span beam-arch combination bridge, including a beam-arch combination bridge 1, a guide beam 2, a cable-stayed device 3, and a pull-down point 4.

[0025] 1. Beam-arch combination bridge: The beam-arch combination bridge is assembled non-in-situ at the assembly site, and after passing the acceptance inspection, it is connected to the guide beam through fully welded nodes to form a whole.

[0026] 2. Guide Beam: The guide beam is a variable-rigidity guide beam with a gradually decreasing cross-section from the root to the end. 2-1 is a double H-shaped truss structure, with both the chord and web members of the H-shaped steel truss structure being H-shaped steel. 2-2 is the tie rod between each set of sheet trusses, made from circular tubes cut at the intersection line at both ends and welded to the sheet trusses. 2-3 is a crossbeam, a triangular tube truss composed of circular tubes, serving as support between the two guide beams. 2-4 is an end crossbeam, a sheet tube truss composed of circular tubes, serving as support between the two guide beams.

[0027] 3. Inclined pulley: The inclined pulley is an important device to prevent the guide beam ends from sagging. It includes 3-1, a fixed base used to fix 3-2 and 3-3 above the guide beam; 3-2, a counterweight; 3-3, a winch assembly; 3-4, a fixed pulley; 3-5, a movable pulley, which alternates between fixed and movable. The wire rope is wound at a 2x rate to reduce the pulling force of the winch; 3-6, a wire rope. 4. Pull-down point: used to fix the wire rope hook; the lifting lug is made of steel plate.

[0028] 5. There are three key points for the installation and application of the guide beam device: First, the guide beam and the beam-arch combination bridge should be welded, with a weld grade of Class 1, full penetration. The guide beam is a variable-length truss-type guide beam. The installation process is as follows: welding the double H-shaped truss structure to the beam-arch combination bridge, installing tie rods to connect the double H-shaped truss structure, installing the crossbeam to connect the two guide beams, and then installing the cable-stayed device.

[0029] Second: The guide beam should be installed in a horizontal position, and the inclined-stayed device should be in a tensioned state but not under stress.

[0030] Third: Before the guide beam passes the pier, measure the elevation of the guide beam end and adjust the elevation of the guide beam end through the inclined pulling device to ensure that the guide beam can be smoothly put on the pier.

[0031] At maximum cantilever, the deflection at the ends of traditional uniform-section trusses or steel plate girders can easily contact the channel limit, or prevent the pier from being raised in one go. This solution utilizes high-rigidity double H-shaped truss segments at the base to provide sufficient bending stiffness. Furthermore, a diagonal-stayed device applies a reverse lifting force at the ends to further reduce deflection. This provides a dual guarantee of "structural stiffness + active lifting," completely eliminating the risk of repeated beam padding and beam drop.

[0032] The inclined pulling device adopts integrated design of winch-movable pulley block, and the steel wire is arranged during the assembly of the guide beam, and when the front end of the guide beam is only 0.5 m away from the top of the pier, the lifting of 75 mm can be completed by starting the winch for only 2 min, and the whole process does not need high-altitude welding, bolt disassembly, and additional equipment. Compared with the conventional method of repeatedly lifting 4-6 h by using a jack and wedge-shaped pads, the key process time is shortened by 95%, the day utilization rate of the pushing operation is increased by more than 15%, and the overall construction period is shortened.

[0033] The double-H type truss structure is composed of small-section H-shaped steel to form a truss system with large rigidity and large section, and the material utilization rate is high, which is suitable for the stress characteristics of the cantilever working condition, and about 40% of material is saved compared with the solid web beam. The inclined pulling device skillfully uses the fixed movable pulley block and the winch to complete the adjustment of the elevation of the end of the guide beam.

[0034] The device has compact and simple structure, light self-weight, material saving, high equipment utilization rate, fast and easy construction method, and can be applied to the construction of bridge pushing and sliding, and has obvious practical significance.

[0035] The present application avoids the repeated adjustment of the inclination angle and height of the traditional guide beam before the upper pier, the inclined pulling device of the present technology is installed before the pushing construction, and the front end of the guide beam can be lifted to the specified elevation once before the guide beam is erected on the upper pier. The process of repeatedly adjusting the elevation of the cushion beam during the beam erection construction is simplified, the construction efficiency is improved, and the present application has operability and safety.

[0036] The above is only an embodiment provided by the present application, and does not limit the present application, although the present application is described in detail with reference to the embodiment, and for those skilled in the art, the technical solutions recorded in the foregoing embodiment can be modified, or some technical features can be replaced, but any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A long-span beam-arch composite bridge top derivation beam device, characterized in that It includes: A beam-arch composite bridge and a variable stiffness guide beam fixed to the front end thereof; The guide beam is composed of: high-rigidity double H-shaped truss section, tie rod, cross beam, and end cross beam from the root to the end; It also includes an oblique pulling device installed above the guide beam and a pull-down point located at the lower edge of the front end of the guide beam; The inclined-stayed device is connected to the lowering point via a steel wire rope and is used to lift the end of the guide beam to the designed elevation of the pier top at one time during the jacking process.

2. The long-span beam-arch composite bridge top derivation beam device according to claim 1, characterized in that: The high-rigidity double H-shaped truss section is composed of two vertically arranged H-shaped steel chords and multiple H-shaped steel webs to form a hollow truss, and the two trusses are connected by tie rods to form a whole.

3. The long-span beam-arch composite bridge top derivation beam device according to claim 2, characterized in that: The tie rod is a round tube, and its two ends are cut through the intersection line and then directly welded to the corresponding nodes of the two trusses to eliminate the node plate and reduce the weight.

4. The long-span beam-arch composite bridge top derivation beam device according to claim 1, characterized in that: The crossbeam is a triangular tube truss composed of round tubes, which is arranged at intervals along the longitudinal direction of the guide beam, and the left and right trusses are horizontally connected to form a closed space truss.

5. The long-span beam-arch composite bridge top derivation beam device according to claim 1, characterized in that: The end cross beam is a sheet-like tube truss composed of round tubes, and also serves as a mounting base for the pull-down point.

6. The long-span beam-arch composite bridge top derivation beam device according to claim 1, characterized in that: The inclined-stayed device includes a fixed base, a counterweight, a winch group, a fixed pulley, a movable pulley, and a steel wire rope; the fixed base is welded to the upper chord of the guide beam, the movable pulley and the fixed pulley form a 2-rate pulley group, one end of the steel wire rope is connected to the winch, and the other end is anchored at the pulley group after passing through the pulley group.

7. The long-span beam-arch composite bridge top derivation beam device according to claim 6, characterized in that: The counterweight block and the winch are arranged together on a fixed base, and are used to balance the winch reaction force and simultaneously reduce the negative bending moment at the root of the guide beam.

8. The long-span beam-arch composite bridge top derivation beam device according to claim 1, characterized in that: The guide beam and the beam-arch combination bridge are fixedly connected by a first-level full penetration weld, and the weld length is not less than 1.5 times the height of the root of the guide beam.

9. The construction method of a long-span beam-arch composite bridge top derivation beam device according to claim 1 is characterized in that It includes: S1 Assemble high-rigidity double H-shaped truss segments, tie rods, cross beams, and end cross beams into an integral guide beam at the assembly site and weld them together with the beam-arch combination bridge; S2 Install the inclined pull device to make the wire rope taut but with zero force; S3 starts the walking-type pushing device to move the combined bridge and the guide beam forward synchronously; S4 When the front end of the guide beam approaches the pier, the end of the guide beam is lifted to the designed elevation of the pier top at one time by retracting the rope with the winch; S5 Continue pushing until the beam-arch combination bridge is fully in place, and remove the guide beam and cable-stayed device for recycling.

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