Bailey beam bearing strengthening method

Abstract

The invention provides a bailey beam bearing strengthening method which comprises the steps that supporting frames are arranged at the connecting positions of bailey beams, the supporting frames are symmetrically arranged according to the midspan, and the heights of the supporting frames are gradually reduced from the midspan to the two ends of the bailey beams; anchor seats are arranged at the two ends of the bailey beam; an inhaul cable is arranged along the free end of the supporting frame, and the two ends of the inhaul cable are introduced into anchor seats; pretension force is applied to the inhaul cables, the inhaul cables apply pressure to the supporting frames, then the pressure is transmitted to the bailey beams, and the bailey beams bear pre-bending. The Bailey beam structure has the beneficial effects that a self-balancing system can be formed through the Bailey beam, the inhaul cables and the supporting frames, internal force distribution is changed, the high tensile property of the high-strength cables can be fully exerted, and the stress performance of the whole structure of the Bailey beam is improved.

Description

Technical Field

[0001] The invention relates to the technical field of bridge engineering, and in particular to a Bailey beam load-bearing strengthening method. Background Art

[0002] Bailey beam is also called Bailey frame, Bailey plate or Bailey truss. In the 1960s, Bailey steel bridge was improved to 321 prefabricated highway steel bridge, also known as 321 Bailey beam, 321 Bailey frame, 321 Bailey plate or 321 Bailey truss. It has been widely used in engineering construction, flood control and rescue due to its convenient transportation and storage, simple installation and strong bearing capacity, playing an irreplaceable role.

[0003] In recent years, bridge construction has expanded to coastal areas, reservoir areas, lake areas, mountainous areas, and deep valleys. The bridge construction environment has become increasingly complex, and bridge construction facilities such as trestles, platforms, and brackets urgently need to have larger spans. In addition, bridge construction equipment has also undergone earth-shaking changes. The models of crawler cranes, rotary drilling rigs, and flatbed transporters are getting larger and larger, and their deadweight has increased from the conventional 50 to 80 tons to 100 to 200 tons. Therefore, the most common Bailey beam as a load-bearing beam has become increasingly limited in its bearing capacity.

[0004] At present, many research institutions have made certain improvements to Bailey beams. For example, China Railway Major Bridge Engineering Group Co., Ltd. has developed a "super Bailey beam", whose weight per linear meter has increased by 59%, bending bearing capacity has increased by 88%, and shear bearing capacity has increased by 113%. The main improvements include: 1. The height of the Bailey beam is adjusted from 1.5m of the 321 type to 2m. 2. The original 321 Bailey beam vertical and diagonal rod material I8 I-beam is adjusted to 80mm rectangular tube; the chord material double 10 channel steel is adjusted to double 14a channel steel. 3. The material is adjusted from 16Mn steel to Q345B.

[0005] CCCC Highway Planning and Design Institute has developed the "HD200 Bailey beam", which has a 33% increase in strength and a 2.3 times increase in stiffness. The main improvements include: 1. The height of the Bailey beam is adjusted from 1.5m of the 321 type to 2m. 2. The profile specifications of the vertical and diagonal bars of the original 321 Bailey beam are improved. 3. The material is adjusted from 16Mn steel to Q345B.

[0006] Xingtu Co., Ltd. developed the "XT300 truss" to further improve the bearing capacity of the Bailey beam. The improvements mainly include: 1. The height of the Bailey beam was adjusted from 1.5m of the 321 type to 3m. 2. The vertical and diagonal bars of the original 321 Bailey beam were adjusted to HM150*100, and the chord material was adjusted from double-jointed 10 channel steel to double-jointed 20b channel steel. 3. The material was adjusted from 16Mn steel to Q355B.

[0007] With the development of engineering technology, the current load-bearing capacity of 321 Bailey beams can no longer meet the needs of the current era. From the above three types of Bailey beam improvement methods, it can be seen that the current mainstream idea is to develop new products to replace 321 Bailey beams. However, after years of accumulation, the current inventory of 321 Bailey beams is huge. If new products are developed to replace them according to the current idea, it will inevitably cause a huge waste of resources. The price of the new Bailey beam is generally 3-5 times that of the 321 Bailey beam, and the cost investment is not cost-effective. Therefore, it is of great significance to provide a method for strengthening the load-bearing of Bailey beams. Summary of the invention

[0008] The purpose of the present invention is to solve at least one of the above-mentioned deficiencies in the prior art. For example, one of the purposes of the present invention is to provide a Bailey beam load-bearing strengthening method that can improve the Bailey beam load-bearing capacity by adding components.

[0009] In order to achieve the above-mentioned purpose, the present invention provides a method for strengthening the bearing capacity of a Bailey beam on one hand, which may include setting a support frame at the lower end of the Bailey beam, the support frame being symmetrically arranged at the mid-span, and the height of the support frame gradually decreasing from the mid-span to the two ends of the Bailey beam; setting anchor seats at both ends of the Bailey beam; setting cables along the free ends of the support frame, and transmitting the two ends of the cables to the anchor seats; applying pre-tension to the cables, the cables applying pressure to the support frame, and then transmitting the pressure to the Bailey beam, so that the Bailey beam can withstand pre-bending.

[0010] According to an exemplary embodiment of one aspect of the present invention, the method may further include providing a through-hole jack at an anchor position at one or both ends of the Bailey beam, and applying tension to the cable through the jack.

[0011] According to an exemplary embodiment of one aspect of the present invention, the method may further include anchoring the cable at anchor seats at both ends, providing a tightening device in the middle of the cable, and applying tension to the cable through the tightening device.

[0012] According to an exemplary embodiment of an aspect of the present invention, the tightening device may include a turnbuckle.

[0013] According to an exemplary embodiment of an aspect of the present invention, the support frame may include a support frame with adjustable height.

[0014] According to an exemplary embodiment of one aspect of the present invention, the method may further include anchoring both ends of the cable to anchor seats, and tightening the cable to be stressed by raising the height of the support frame.

[0015] According to an exemplary embodiment of an aspect of the present invention, a saddle may be provided on the free end of the support frame.

[0016] According to an exemplary embodiment of an aspect of the present invention, the Bailey beam may include a 321 Bailey beam.

[0017] According to an exemplary embodiment of an aspect of the present invention, the cable may include a prestressed steel strand.

[0018] According to an exemplary embodiment of an aspect of the present invention, the anchor seat and the Bailey beam may be connected by a steel pin.

[0019] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0020] (1) The Bailey beam load-bearing strengthening method proposed in the present invention can achieve the goal of improving the load-bearing capacity by adding simple components to the Bailey beam. The formed Bailey beam has a simple overall structure and clear mechanical principles.

[0021] (2) The Bailey beam load-bearing strengthening method proposed in the present invention can effectively solve the problem of insufficient bearing capacity of the current 321 Bailey beam, thereby expanding the application scenarios and working conditions of the 321 Bailey beam.

[0022] (3) The production cost of the Bailey beam load-bearing strengthening method proposed in the present invention is controllable, which expands the application scenarios and working conditions of the existing Bailey beams and can avoid the idle waste of the current huge inventory of 321 Bailey beams. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other objects and features of the present invention will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0024] Figure 1 A schematic diagram showing the structure of a Bailey beam in a Bailey beam load-bearing strengthening method of the present invention is shown;

[0025] Figure 2 A schematic diagram of the elevation structure of a Bailey beam in the Bailey beam load-bearing strengthening method of the present invention is shown;

[0026] Figure 3 A schematic diagram of the detailed structure of a support frame of a Bailey beam in the Bailey beam load-bearing strengthening method of the present invention is shown.

[0027] Description of main reference numerals:

[0028] 1- support frame, 2- anchor seat, 3- cable, 4- Bailey beam. DETAILED DESCRIPTION

[0029] Hereinafter, a Bailey beam load-bearing strengthening method of the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments.

[0030] In the description of the present application, it should be understood that the terms "middle", "upper", "lower", "left", "right", "top", "bottom", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present invention, unless otherwise specified, "several" and the like mean two or more. In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] Exemplary Embodiment 1

[0032] This exemplary embodiment provides a Bailey beam load-bearing strengthening method.

[0033] like Figure 1 to Figure 3 As shown in , the Bailey beam load-bearing strengthening method of this exemplary embodiment may include:

[0034] A plurality of support frames 1 are arranged at the lower end of the Bailey beam 4. The Bailey beam 4 includes a plurality of Bailey plates connected in sequence. The support frames 1 can be arranged at the connection positions of the Bailey plates. Here, it is not necessary to set the support frames at each Bailey plate connection position. The setting principle is to arrange them symmetrically in the mid-span. The height of the support frame 1 is set to gradually decrease from the mid-span to the two ends. The height of the support frame 1 in the middle of the Bailey beam 4 is the highest. The height of the support frame 1 from the middle to the left and right ends is smaller, and the support frames 1 on the left and right ends of the Bailey beam 4 are symmetrical. A saddle is set at the free end of the support frame 1. Anchor seats 2 are respectively set at the left and right ends of the Bailey beam 4. The cable 3 is passed through the anchor seat 2 and the cable saddle in the order from one end of the Bailey beam 4 to the other end, so that the cable is stretched at the anchor seat 2 at one end or both ends, and the cable 3 applies pressure to the cable saddle, thereby achieving the purpose of transmitting the pressure to the Bailey beam 4 and realizing that the Bailey beam 4 is subjected to pre-bending. The curve shape formed by the cable 3 can be adjusted to meet various load bearing requirements with a smaller cable force.

[0035] In this exemplary embodiment, the Bailey beam may include a 321 Bailey beam.

[0036] In this exemplary embodiment, the functions of the anchor seat may include: serving as a force bearing point for cable tensioning, being connected to the end of the Bailey beam to transmit the force of the cable to the Bailey beam; any component that achieves this function can be applied to both ends of the Bailey beam and is not limited to the anchor seat.

[0037] In this exemplary embodiment, the size of a single Bailey sheet can be 2 to 4 meters in length, such as 3 meters, and 1 to 2 meters in height, such as 1.5 meters. The end can be designed as a male and female head. When connecting, the male head is inserted into the female head, and then the steel pin is inserted horizontally to extend and assemble into a Bailey beam.

[0038] Furthermore, anchor seats are arranged at both ends of the Bailey beam, and the anchor seats can be connected to the female head / male head through steel pins.

[0039] In this exemplary embodiment, the arrangement position, spacing and height of the support frames are symmetrical about the mid-span of the Bailey beam. The spacing distance between them can be determined by finite element analysis according to the total length of the Bailey beam, cable specifications, etc., and is not specifically limited.

[0040] In this exemplary embodiment, the support frame may include a support frame with adjustable height, which is designed as a retractable structure and can be realized by hydraulic and mechanical means. The principle followed in setting the height of the support frame is to gradually reduce the length from the mid-span to both ends, and the height needs to be symmetrical about the mid-span. The specific height change will be affected by factors such as the span, and is determined by finite element analysis for specific projects.

[0041] Furthermore, an oil jack or a mechanical jack may be provided on the support frame to extend the support frame.

[0042] In this exemplary embodiment, if the pre-tension and graded loading can be appropriately applied in stages during the construction process, it will be possible to reduce the force of the supporting structure to a minimum. For example, method one: a through-hole jack is set at the anchor position at one or both ends, and the cable can use prestressed steel strands, and tension is applied through the jack. This method is the best method. Method two: The cable is anchored at the anchors at both ends, and a tightening device is set in the middle of the cable, and tension is applied by tightening. Generally, a basket bolt is set. Method three: The way to apply force to the cable body is to anchor the two ends of the cable to the anchor seats, and by raising the height of the support frame, the cable is tightened and stressed in disguise.

[0043] The method of the present invention is effective for all beams, and its core principle is mainly the "beam string" theory. Considering the current situation that the inventory of 321 Bailey beams is large, but the bearing capacity gradually cannot meet the requirements, alternative products such as HD200, XT300 and "super Bailey beams" have appeared. To realize the utilization of 321 Bailey beams, auxiliary measures need to be taken to strengthen them. The innovation points of the method of the present invention are mainly: 1. Setting a support frame at the connection position of the Bailey beam; 2. Setting anchor seats at both ends of the Bailey beam; 3. Setting cables along the top of the support frame and passing the cables into the anchor seats; 4. Applying cable force to the cables; Method 1: The cable body can be tensioned through the anchor seat position (corresponding to method 1: the conventional practice is to set a through-hole jack at one end or both ends of the anchor seat position, and the cable uses prestressed steel strands, and the tension is applied by the jack), Method 2: The support frame can be extended by oil top or mechanical top; 5. By adjusting the cable to form a curved shape, the optimal form of various loads can be met, and the bearing requirements can be met under a small cable force.

[0044] The principle of the method of the present invention may include: the stress mechanism of forming the overall structure is to apply pre-tension in the lower cable to make the Bailey beam produce deflection, so that the final deflection of the structure under load is reduced, and the support frame provides elastic support for the Bailey beam to improve the stress performance of the structure. The Bailey beam, the cable and the support frame form a self-balancing system, which changes the internal force distribution and can give full play to the strong tensile performance of the high-strength cable, thereby improving the stress performance of the overall structure, so that the Bailey beam and the cable complement each other and work together to achieve self-balance, giving full play to the role of each structure. If the pre-tension and loading are appropriately applied in stages during the construction process, it is possible to reduce the force of the supporting structure to a minimum.

[0045] Exemplary Embodiment 2

[0046] This exemplary embodiment provides a Bailey beam with enhanced load-bearing properties.

[0047] The load-bearing strengthened Bailey beam of this exemplary embodiment can be obtained by the Bailey beam load-bearing strengthening method described in the above exemplary embodiment 1.

[0048] The load-bearing strengthened Bailey beam may include a Bailey beam, a supporting frame, a cable and an anchor seat.

[0049] Among them, several support frames are arranged at the lower end of the Bailey beam. Here, in the length direction of the Bailey beam, the support frames are arranged symmetrically in the mid-span, and there is no need to set support frames at each connection position. The height of the support frame is set to gradually decrease from the mid-span to the two ends. A saddle is provided at the free end of the support frame (the end not connected to the Bailey beam). The height of the support frame is adjustable. Anchor seats are respectively provided at the two ends of the Bailey beam. The two ends of the cable are respectively passed into the anchor seats, and the cable body passes through the saddles on several support frames.

[0050] In this exemplary embodiment, an oil top or a mechanical top may be provided on the support frame.

[0051] In this exemplary embodiment, the Bailey beam may include a 321 Bailey beam.

[0052] In this exemplary embodiment, the Bailey sheet ends can be designed as male and female heads. When connecting the Bailey sheets, the male head can be inserted into the female head, and then the steel pin can be inserted horizontally to lengthen and assemble into a Bailey beam. The size of a single Bailey sheet can be 3m in length and 1.5m in height.

[0053] Furthermore, the anchor seat may be connected to the Bailey beam via a steel pin.

[0054] In summary, the beneficial effects include:

[0055] The present invention provides a Bailey beam load-bearing strengthening method, which is mainly used in the field of bridge engineering. The beneficial effects and advantages of the present invention are mainly reflected in five aspects: 1. By adding simple components to the 321 Bailey beam, the target of improving the load-bearing capacity can be achieved, the overall structure is simple, and the mechanical principle is clear; 2. The method of the present invention can effectively solve the current problem of insufficient load-bearing capacity of the 321 Bailey beam, so that the application scenarios and working conditions of the 321 Bailey beam are expanded, and the idle waste of the current huge inventory of 321 Bailey beams is avoided; 3. The method of the present invention has simple operation steps, low difficulty for construction workers to learn and master, and low cost for promotion and application; 4. The device (Bailey beam after load-bearing strengthening) formed by the present invention is concise, and the components and equipment are easy to obtain. Centralized intelligent control can be achieved through electrical systems, hydraulic systems, stress sensors, displacement sensors and information technology, which lays a good foundation for access to infrastructure digital engineering; 5. Under the existing industrial system, the conventional or production difficulty of each component is low, the production cost is controllable, and the promotion and application prospects are broad.

[0056] Although a Bailey beam load-bearing strengthening method of the present invention has been described above in conjunction with exemplary embodiments, it should be clear to those skilled in the art that various modifications and changes may be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined by the claims.

Claims

1. A Bailey beam load-bearing strengthening method, characterized in that: The method comprises: A support frame is set at the lower end of the Bailey beam. The support frame is symmetrically arranged at the mid-span, and the height of the support frame gradually decreases from the mid-span to the two ends of the Bailey beam. Anchors are provided at both ends of the Bailey beam; A cable is arranged along the free end of the support frame, and both ends of the cable are passed into the anchor seat; Pre-tension is applied to the cables, which apply pressure to the support frame, and then the pressure is transmitted to the Bailey beam, so that the Bailey beam can withstand pre-bending.

2. The Bailey beam load-bearing strengthening method according to claim 1, characterized in that: The method further comprises arranging a through-hole jack at the anchor seat position at one end or both ends of the Bailey beam, and applying tension to the cable through the jack.

3. The Bailey beam load-bearing strengthening method according to claim 1, characterized in that: The method also includes anchoring the cable at two end anchor seats, arranging a tightening device in the middle of the cable, and applying tension to the cable through the tightening device.

4. The Bailey beam load-bearing strengthening method according to claim 3, characterized in that: The tightening device includes a turnbuckle bolt.

5. The Bailey beam load-bearing strengthening method according to claim 1, characterized in that: The support frame comprises a support frame with adjustable height.

6. The Bailey beam load-bearing strengthening method according to claim 5, characterized in that: The method also includes anchoring both ends of the cable to anchor seats, and tightening the cable to bear stress by raising the height of the support frame.

7. The Bailey beam load-bearing strengthening method according to claim 1, characterized in that: A cable saddle is arranged on the free end of the support frame.

8. The Bailey beam load-bearing strengthening method according to claim 1, characterized in that: The Bailey beam includes a 321 Bailey beam.

9. The Bailey beam load-bearing strengthening method according to claim 1, characterized in that: The cables include prestressed steel strands.

10. The Bailey beam load-bearing strengthening method according to claim 1, characterized in that: The anchor seat is connected to the Bailey beam through a steel pin.

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