A method for erecting a steel truss arch bridge capable of actively adjusting the internal force and displacement of the entire bridge

Abstract

The present invention belongs to the technical field of steel truss arch bridge erection, and specifically relates to a method for erecting a steel truss arch bridge that can actively adjust the internal force and displacement of the entire bridge. Steel trusses are respectively erected on two main piers, so that one end of the steel truss is erected along the center of the two main piers and forms an arch rib cantilever; cable towers are respectively erected on the two main piers, and the steel trusses are continuously erected along the arch rib cantilever, so that a number of cables on the cable towers are respectively connected to a number of steel trusses as the steel trusses are erected; a pressure sensor is set between every two adjacent steel trusses, and the pressure data of the corresponding steel trusses when they are connected is detected by the pressure sensor and uploaded to a control device; by adjusting the cable force of the cable on the cable tower, the cantilevers on both sides are lifted upward and the connection opening is expanded to be greater than or equal to the width of the steel truss, and at the same time, a number of cables adjust the cable force according to the pressure sensor data at different positions, so that the force between the steel trusses at different positions is uniform; it can make the steel trusses on the arch rib cantilever be uniformly stressed.

Description

Technical Field

[0001] The invention belongs to the technical field of steel truss arch bridge erection, and in particular relates to a steel truss arch bridge erection method capable of actively adjusting the internal force and displacement of the entire bridge. Background Art

[0002] The steel truss arch bridge is a special bridge structure that combines the advantages of steel trusses and arch bridges. It has the characteristics of reasonable force, material saving, light weight, and large spanning capacity. In the steel truss arch bridge, the steel truss as the upper structure of the bridge bears the load of the bridge deck and transfers it to the arch foot. The arch bridge disperses the load to the piers through its special curved shape, and generates horizontal thrust at the same time, making the bridge more stable when subjected to force. The steel truss arch bridge is suitable for the construction of bridges with poor foundations and large spans. Since the steel truss has a light weight and small pressure on the foundation, it is suitable for areas with poor foundation conditions. At the same time, the steel truss arch bridge has a large spanning capacity and can meet the needs of large-span bridges.

[0003] During the construction of the steel truss arch bridge, the steel truss is erected based on the main pier as the fulcrum. The structure composed of the steel truss erected from the main pier on either side to the temporary pier on that side is the side span steel beam, and the structure composed of the two main piers is the main span steel beam. When constructing the main span steel beam, the main pier is used as the starting section of the main span steel beam for construction, and it is simultaneously erected towards the middle based on the main pier, so that the main span steel beam is gradually connected. The parts on both sides suspended above the water before the connection are the arch rib cantilevers. When the arch rib cantilevers on both sides are gradually erected to the joint position, only the last section of the steel truss is left to be installed. Since the arch rib cantilevers on both sides have a certain dead weight, if only one end has a fulcrum, the side without the fulcrum will tilt and move closer to the center under gravity. When the arch rib cantilevers on both sides move closer to the middle at the same time, the space at the joint will not be enough to install the last section of the steel truss originally designed. Therefore, in general, a sling tower is erected on the two main piers, and then a sling is passed through the sling tower, so that one end of the sling is connected to the arch rib cantilever, and the other end is connected to the side span steel beam. Then, the sling force is adjusted to lift the inclined arch rib cantilever and expand the space of the middle joint to facilitate the installation of the last section of the steel truss. The sling force is generally adjusted by adjusting the length of the sling, or by adjusting the tension of the sling by counterweighting the sling.

[0004] However, in the prior art, the adjustment of the arch rib cantilever is generally performed directly by stretching the cables, and there are multiple cables connected to the steel trusses of the arch rib cantilever. When the cable tension of multiple cables is adjusted synchronously at the same time, although the arch rib cantilever can be lifted, due to the arc-shaped arch rib cantilever, when the cable tension of the cables connected to different steel trusses on the arch rib cantilever is adjusted at the same time, it will cause uneven force on different parts of the lifted arch rib cantilever, that is, on the contact surface of two adjacent steel trusses, the contact points at the top will be squeezed against each other due to the horizontal component of the inclined upward pulling force of the cables, while the contact points at the bottom tend to separate from each other due to the upward lifting of the arch rib cantilever. Therefore, the contact points at the bottom are less stressed than those at the top, and the forces at the two places form an unbalanced state. When the force at the upper contact point approaches or exceeds the limit value, it is easy to cause deformation of the steel truss.

[0005] Based on this, a method for erecting a steel truss arch bridge that can actively adjust the internal force and displacement of the entire bridge is proposed. Summary of the invention

[0006] In order to solve the problem in the prior art that directly adjusting the arch rib cantilever by slings to lift the arch rib cantilever will cause uneven force on different positions of the steel truss on the arch rib cantilever, the present invention provides a steel truss arch bridge erection method that can actively adjust the internal force and displacement of the entire bridge.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A method for erecting a steel truss arch bridge capable of actively adjusting the internal force and displacement of the entire bridge of the present invention comprises the following steps:

[0009] Step 1: Erect steel trusses on the two main piers respectively, so that one end of the steel trusses is erected along the direction of the temporary pier to form a side span joint, and the other end is erected along the center of the two main piers to form an arch rib cantilever;

[0010] Step 2: erecting cable towers on the two main piers respectively, and continuing to erect steel trusses along the arch rib cantilever, so that a number of cables on the cable towers on the corresponding side are respectively connected to a number of steel trusses as the steel trusses are erected;

[0011] Step 3: a pressure sensor is arranged between every two adjacent steel trusses, the pressure data of the corresponding steel trusses when they are connected is detected by the pressure sensor, and the pressure data is uploaded to the control device;

[0012] Step 4: By adjusting the cable force of the sling tower crane, the cantilevers on both sides are lifted upward and the joint mouth is expanded to be greater than or equal to the width of the steel truss. At the same time, several slings adjust the cable force according to the pressure sensor data at different positions to make the force between the steel trusses at different positions uniform;

[0013] Step 5: Install the last section of steel truss at the joint position to complete the joint.

[0014] Furthermore, the pressure sensors are arranged at the upper and lower ends of the contact position of two adjacent steel trusses.

[0015] Furthermore, a plurality of slings at adjacent connection positions form a tension group, and the plurality of tension groups adjust the cable forces in sequence from bottom to top according to the connection positions.

[0016] Furthermore, a plurality of tension groups implement a cycle of cable force adjustment from bottom to top, which is an adjustment period. The adjustment range of each cable force adjustment is controlled by a control device. The control device has a preset number of adjustment cycles. After the number of adjustment cycles is reached, the plurality of tension groups stop adjusting the cable force.

[0017] Furthermore, distance sensors are respectively arranged on the steel trusses on both sides of the closure position, and the distance sensors are electrically connected to the control device. The distance sensors are used to detect the size of the closure. The control device is preset with a target distance. A plurality of tension groups implement a cycle of cable force adjustment from bottom to top, which is an adjustment cycle. When the cable force is adjusted cyclically for a number of adjustment cycles until the width of the closure reaches the target distance, the cycle is stopped.

[0018] Furthermore, the cable force adjustment amount is gradually reduced according to the superposition of the adjustment cycle number until it is adjusted to reach the adjustment cycle number or the target distance.

[0019] Furthermore, the tie beam is connected to the bottom of the arch rib cantilever through a hanger, and a position sensor is provided on the arch rib cantilever. The position sensor is electrically connected to the control device, and the detection area of ​​the position sensor is located on the tie beam and perpendicular to the bottom of the position sensor. Several tension groups correct the cable force adjustment range according to the position sensor data during the cyclic adjustment to keep the hanger in a relatively vertical state.

[0020] Furthermore, after the last section of the steel truss is installed on one side of the arch rib cantilever, the control device controls the plurality of tension groups to reversely execute the adjustment cycle, so that the arch rib cantilevers on both sides are connected to the last section of the steel truss.

[0021] Furthermore, when the adjustment cycle is executed in reverse, the cycle is stopped when the pressure sensor data no longer changes.

[0022] The beneficial effects of the present invention are as follows: by arranging a pressure sensor between every two adjacent steel trusses, the data of the pressure sensor is transmitted to the control device in real time, and the control device is electrically connected to the adjusting device of the suspension cable at the same time, and each suspension cable is connected to the corresponding steel truss one by one, and when adjusting the cable force, the cable force of the corresponding connection position is adjusted in real time according to the data of each pressure sensor, so that when the arch rib cantilever is lifted upward, the force difference at different positions of the steel truss is small, and each steel truss can be evenly stressed, avoiding the phenomenon of stress concentration, and improving the strength of the steel truss arch bridge during installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0024] Figure 1 It is a structural schematic diagram of the steel truss arch bridge of the present invention;

[0025] Figure 2 It is a schematic diagram of the synchronous construction of the arch beams of the steel truss arch bridge of the present invention;

[0026] Figure 3 It is a structural schematic diagram of adjusting the cable force of the sling of the steel truss arch bridge of the present invention;

[0027] Figure 4 It is a schematic diagram of the internal top view of the cable force regulating device of the present invention;

[0028] Figure 5 It is a schematic diagram of the internal side view structure of the cable force adjustment device of the present invention in which the fixed gear and the connecting gear are meshed;

[0029] Figure 6 It is a schematic diagram of the internal side view of the cable force adjustment device of the present invention, in which the transmission gear and the connecting gear are meshed;

[0030] Explanation of the accompanying reference numerals: 1. steel truss; 2. main pier; 3. tower; 4. sling; 5. crane; 6. boom; 7. box; 8. motor; 9. transmission shaft; 10. transmission gear; 11. winch; 12. connecting gear; 13. rotating shaft; 14. fixed gear; 15. bracket. DETAILED DESCRIPTION

[0031] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0032] like Figure 1-3 As shown, the method for erecting a steel truss arch bridge of the present invention can actively adjust the internal force and displacement of the entire bridge. It includes the following steps:

[0033] Step 1: erect steel trusses 1 on the two main piers 2 respectively, so that one end of the steel trusses 1 is erected along the direction of the temporary pier to form a side span joint, and the other end is erected along the center of the two main piers 2 to form an arch rib cantilever;

[0034] Step 2: erecting the slings 4 towers 3 on the two main piers 2 respectively, and continuing to erect the steel trusses 1 along the arch rib cantilever, so that one end of the slings 4 on the slings 4 towers 3 on the corresponding side is connected to the steel trusses 1 respectively as the steel trusses 1 are erected, and at the same time, the other end of the slings 4 passes through the towers 3 and is connected to the side span steel beam;

[0035] Step 3: a pressure sensor is arranged between every two adjacent steel trusses 1, and the pressure data of the corresponding steel trusses 1 when they are connected is detected by the pressure sensor, and the pressure data is uploaded to the control device;

[0036] Step 4: By adjusting the cable force of the cable 4 on the tower crane, the cantilevers on both sides are lifted upward and the joint mouth is expanded to be greater than or equal to the width of the steel truss 1. At the same time, several cables 4 adjust the cable force according to the pressure sensor data at different positions to make the force between the steel trusses 1 at different positions uniform;

[0037] Step 5: Install the last steel truss 1 at the joint opening position by crane 5 to complete the joint.

[0038] During the construction of the steel truss arch bridge, the steel truss beam 1 is erected based on the main pier 2 as a fulcrum. The structure composed of the steel truss beam 1 erected from the main pier 2 on any side to the temporary pier on that side is the side span steel beam, and the structure composed of the two main piers 2 is the main span steel beam. When constructing the main span steel beam, the main pier 2 is used as the starting section of the main span steel beam for construction, and it is simultaneously erected and moved closer to the middle based on the main pier 2, so that the main span steel beam is gradually connected. The parts on both sides suspended above the water before the connection are arch rib cantilevers. When the arch rib cantilevers on both sides are gradually erected to the joint mouth position, only the last section of the steel truss beam 1 is left to be installed. Since the arch rib cantilevers on both sides have a certain dead weight, if only one end has a fulcrum, the side without the fulcrum will tilt and move closer to the center under gravity. When the arch rib cantilevers on both sides move closer to the middle at the same time, the space at the joint mouth will be insufficient to install the last section of the steel truss beam 1 originally designed. Therefore, in general, the sling 4 tower 3 is set up on the two main piers 2, and then the sling 4 is passed through the sling 4 tower 3, so that one end of the sling 4 is connected to the arch rib cantilever, and the other end is connected to the cable force adjustment device on the side span steel beam, and then the inclined arch rib cantilever is lifted by adjusting the cable force of the sling 4 to expand the space of the middle joint, so as to facilitate the installation of the last section of the steel truss 1. The way to adjust the cable force of the sling 4 is generally to adjust the length of the sling 4 through the cable force adjustment device, or to adjust the tension of the sling 4 by counterweighting. When one end of the arch rib cantilever is lifted, from a microscopic perspective, the deformation and displacement between adjacent steel trusses 1 are relatively small, while from a macroscopic perspective of the entire arch rib cantilever, the matching gap and deformation between each steel truss 1 will form a larger adjustment range of the arch rib cantilever after the superposition.

[0039] However, in the prior art, the adjustment of the arch rib cantilever is generally performed directly by stretching the sling 4, and a plurality of slings 4 are connected to the arch rib cantilever. When the cable tension of the plurality of slings 4 is adjusted synchronously at the same time, although the arch rib cantilever can be lifted, due to the arch rib cantilever being in an arc shape, when the cable tension of the slings 4 connected to different positions on the arch rib cantilever is adjusted simultaneously, it will cause uneven force on different parts of the lifted arch rib cantilever, that is, on the contact surface of two adjacent steel trusses 1, the contact points at the top will be squeezed against each other due to the horizontal component force of the inclined upward pulling force of the slings 4, while the contact points at the bottom will tend to separate from each other due to the upward lifting of the arch rib cantilever. Therefore, the contact points at the bottom are less stressed than the contact points at the top, and the forces at the two places are uneven. When the force at the upper contact point approaches or reaches the limit value, , it is easy to cause the steel truss 1 to deform or the connection point of the steel truss 1 to break. Therefore, in order to avoid this risk, a pressure sensor is set between every two adjacent steel trusses 1, so that the data of the pressure sensor is transmitted to the control device in real time, and the control device is electrically connected to the adjustment device of the sling 4 at the same time, through each sling 4 and the corresponding steel truss 1 are connected one by one, and when adjusting the cable force of the sling 4, the cable force of the sling 4 at the corresponding connection position is adjusted in real time according to the data of each pressure sensor, so that when the arch rib cantilever is lifted upward, the upper and lower parts of each steel truss 1 can be evenly stressed, or the force difference at the upper and lower ends is kept within a small difference range, ensuring that the pressure sensor data difference at the upper and lower ends of the steel truss 1 is less than half of the preset limit value, avoiding stress concentration and improving the strength of the steel truss arch bridge.

[0040] like Figure 4-6Since each sling 4 needs to be adjusted separately according to the pressure sensor data on all steel trusses 1, each sling 4 needs to be connected to a cable force adjustment device separately. The cable force adjustment device is arranged on the side span steel beam. The cable force adjustment device includes a box body 7, a transmission shaft 9, a plurality of winches 11 and a transmission gear 10. Each winch 11 is concentrically connected with a connecting gear 12. The transmission shaft 9 passes through the box body 7 and is connected to the motor 8 for transmission. The axial surface of the transmission shaft 9 is provided with teeth. The rotating shaft 13 of the transmission gear 10 can be lifted and lowered, and the position in the horizontal direction can be adjusted. The lifting and lowering can be achieved by a cylinder, and the horizontal movement can be achieved by connecting a screw rod assembly to the connecting piece of the rotating shaft 13. The transmission gear 10 adjusts the height and the horizontal position to achieve transmission connection with the transmission shaft 9, and with one of the winches 11. The connecting gear 12 is used for transmission connection to realize the transmission of the motor to the winch 11. When each sling 4 is adjusted, the transmission gear 10 is meshed with the corresponding connecting gear 12 to realize transmission, and the adjustment of the rope force of the sling 4 is realized by adjusting the torque output by the motor 8. At the same time, a fixed gear 14 is provided above each winch 11, and the fixed gear 14 is rotatably connected to the inside of the box body 7 through a connecting rod. When the transmission gear 10 is not meshed with the connecting gear 12 on the winch 11, the corresponding fixed gear 14 is meshed with the connecting gear 12 to fix the winch 11 and prevent the sling 4 on the winch 11 from retracting. When the transmission gear 10 moves upward to mesh with the connecting gear 12, the bracket 15 on the shaft sleeve outside the rotating shaft 13 will lift the fixed gear 14 to disengage the fixed gear 14 from the connecting gear 12.

[0041] Since the upper and lower ends of some steel trusses 1 will be subjected to extrusion pressure respectively when the arch rib cantilever is adjusted to different positions by the sling 4, in order to prevent the upper and lower ends of the steel trusses 1 from being subjected to extrusion pressure exceeding the design standard value, two pressure sensors are respectively arranged on the upper and lower ends of the contact position of two adjacent steel trusses 1, so that the arch rib cantilever can be evenly stressed during the lifting process.

[0042] Since the main parts of the arch rib cantilever arms on both sides are arc-shaped with openings downward, the parts used to connect with the last steel truss beam 1 are located on the side, and the stretching of the arch rib cantilever arms by the sling 4 in the prior art will cause the two arch rib cantilever arms to form an upward tilted angle on one side used to connect with the last steel truss beam 1, resulting in the need for continuous fine-tuning during installation, or the need for adjustment with the aid of other auxiliary tools, so that the butt joints of the two arch rib cantilever arms can be aligned with the butt joints of the last steel truss beam 1 and connected and installed, resulting in inconvenience in installation and a waste of more manpower;

[0043] In the present embodiment, in step four, specifically, several cables 4 at adjacent connection positions are formed into a tension group, and the tension of the several tension groups is adjusted in sequence from bottom to top according to the connection positions, and each time the tension is adjusted, the pressure difference of the pressure sensors at the upper and lower ends of the contact surface of each steel truss 1 is kept smaller than the limit value preset in the control device; in order to ensure that the docking part of the arch rib cantilever located on the side can always maintain a parallel state with the docking surface of the last section of the steel truss 1. The sling 4 is connected on the arch rib cantilever along the installation direction of the steel truss 1 of the arch rib cantilever, and the arch rib cantilever is an arc from low to high from the side close to the sling 4 to the side away from the sling 4. Therefore, when the arch rib cantilever is lifted, the cable force is gradually adjusted from low to high, that is, the steel truss 1 at the lower position is first subjected to force and lifts the entire arch rib cantilever and changes the inclination angle, and then the steel truss 1 from bottom to top is gradually subjected to force under the action of the sling 4 and moves to the side close to the sling 4. In this process, since the docking surface is on the side away from the sling 4, the sling 4 on the steel truss 1 at this position is the last to be adjusted. Since there are a large number of slings 4 connected to the arch rib cantilever, in order to improve construction efficiency, multiple adjacent slings 4 can be made into a tension group, which are adjusted synchronously when adjusting the cable force. After the arch rib cantilever is adjusted by several slings 4, the space of the joint formed between the arch rib cantilever on both sides is sufficient for installing the last section of steel truss 1. At the same time, since the steel truss 1 on the side away from the slings 4 is adjusted last, the slings 4 below it can be adjusted according to the inclination angle of its connecting surface. When the space of the joint after the adjustment of the slings 4 in the lower connecting position is sufficient for installing the last section of steel truss 1, there is no need to continue to adjust upwards, thus saving construction time.

[0044] Since the above-mentioned embodiment adjusts the cable force of the arch rib cantilever from bottom to top, it will appear that the steel truss 1 at the bottom is adjusted to its design limit by the cable 4 in its tension group before the tension group at the top is adjusted. In this case, the steel truss 1 that has not yet been adjusted to the upper part of the arch rib cantilever will have enough space for construction at the joint, but it is easy to cause damage to the connection part of the steel truss 1 at the bottom. Each time the steel truss 1 at the bottom is stretched to its limit position by the cable 4, the adjacent steel truss 1 at this position will be greatly displaced, and it is not easy to reset after the installation is completed, resulting in a reduction in the service life of the steel truss 1. In order to ensure that the arch rib cantilever is adjusted to a uniform force and to increase the service life of the steel truss 1, when adjusting the cable force of the cable 4 on several tension groups, several tension groups implement a cycle of cable force adjustment from bottom to top as one adjustment cycle. The adjustment range of each cable force adjustment is controlled by a control device. The control device is preset with the number of adjustment cycles. After the number of adjustment cycles is reached, several tension groups stop adjusting the cable force.

[0045] That is, the original method of adjusting the cable force of the sling 4 so that some steel trusses 1 on the arch rib cantilever reach their adjustment limit, while some steel trusses 1 are not adjusted, is changed to adjusting all steel trusses 1 by adjusting the cable force of the sling 4. At the same time, due to the increase in the number of slings 4 and steel trusses 1 involved in the adjustment, the amount of adjustment required for each sling 4 and steel truss 1 that needs to be adjusted is greatly reduced. In order to improve the adjustment accuracy during the cable force adjustment process of the sling 4, all the slings 4 connected to the arch rib cantilever are adjusted once for one cycle. The adjustment amount of each sling 4 in each cycle is small, and each sling in each cycle has a smaller adjustment amount. The 4 cable force adjustment amount can be the minimum adjustment amount allowed during construction, which can not only ensure that the single steel truss 1 is not subjected to excessive force during the adjustment process, but also improve the adjustment accuracy of the cable force of the sling 4 on the position of the steel truss 1. The number of adjustment cycles is preset in the control device, and the number of adjustment cycles is the number of cycles required to complete the joint space adjustment of the arch rib cantilever. The number of adjustment cycles can be set according to the actual situation on site. After the adjustment is completed through the preset number of adjustment cycles, if the joint space is still not enough to install the last section of the steel truss 1, the number of adjustment cycles can be input again through the control device to continue the adjustment until the joint space is sufficient.

[0046] In addition to being able to realize adjustment by presetting the number of adjustment cycles as in the above-mentioned embodiment, since the widths of the steel trusses 1 on different arch rib cantilevers are different, the required installation spaces are also different, so it is necessary to set different space sizes according to the widths of different steel trusses 1. Therefore, unlike the above-mentioned embodiment, in this embodiment, distance sensors are respectively set on the steel trusses 1 on both sides of the joint mouth position, and the distance sensors are electrically connected to the control device. The distance sensors are used to detect the size of the joint mouth. The control device is preset with a target distance. A plurality of tension groups realize a cycle of cable force adjustment from bottom to top, which is an adjustment cycle. When the cable force is adjusted cyclically by the number of adjustment cycles until the width of the joint mouth reaches the target distance, the cycle is stopped;

[0047] The distance sensor is used to detect the width of the joint. The width of the joint is monitored in real time and adjusted in conjunction with each adjustment cycle. The side connection surface of the arch rib cantilever is always kept parallel to the connection surface of the last section of the steel truss 1 by adjusting the arch rib cantilever from bottom to top. At the same time, since each adjustment is the minimum adjustment amount, when stress concentration occurs in some positions, it can also be adjusted in time to avoid damage to some steel trusses 1 or connecting parts between steel trusses 1. The same effect can be achieved through this embodiment, and operation time and manpower can be further saved. Compared with the above embodiment, there is no need for manual observation or detection of the size of the joint, which improves work efficiency.

[0048] Although the arch rib cantilever is cyclically adjusted through the adjustment cycle in the above embodiment, and the amount of each cable force adjustment of the sling 4 is the minimum adjustment amount that can be achieved, so as to ensure that each steel truss 1 can be in a state of uniform force and not easily damaged during the adjustment process, the small amount of cable force adjustment of the sling 4 each time will lead to low adjustment efficiency, and more cyclic adjustment cycles are required. Therefore, in order to improve the construction efficiency and the adjustment efficiency of the arch rib cantilever position, in one embodiment, the cable force adjustment amount is gradually reduced according to the superposition of the number of adjustment cycles until it is adjusted to reach the number of adjustment cycles or the target distance;

[0049] That is, when adjusting the cable tension of the suspension cable 4 connected to different positions on the arch rib cantilever, since the adjustment space is large, the adjustment amount in the initial stage of the adjustment cycle is large to improve the adjustment efficiency in the initial stage. When the adjustment is gradually adjusted to the point where the preset number of adjustment cycles is about to be reached or the joint space between the two arch rib cantilevers is about to reach the target distance, the adjustment amount in the adjustment cycle in the final stage is smaller. In order to gradually improve the adjustment accuracy during the entire adjustment process, the adjustment amount is gradually reduced according to the superposition of the number of adjustment cycles. The scheme in this embodiment can not only ensure construction efficiency, but also ensure the balance of the stress state of the steel truss 1 on the arch rib cantilever and avoid stress concentration.

[0050] Since the adjustment of the arch rib cantilever in the above embodiment is performed from bottom to top, and the connection surface on the arch rib cantilever is made parallel to the connection surface of the last steel truss beam 1 as much as possible, there is still a certain probability that the connection surface will not be parallel due to the adjustment accuracy or matching error. In order to avoid this problem as much as possible and to improve the installation efficiency of the last steel truss beam 1 after the adjustment of the arch rib cantilever is completed, in one embodiment, the tie beam is connected to the bottom of the arch rib cantilever through the hanger 6, and a position sensor is provided on the arch rib cantilever. The position sensor is electrically connected to the control device, and the detection area of ​​the position sensor is located on the tie beam and perpendicular to the bottom of the position sensor. In the cyclic adjustment, several tension groups correct the cable force adjustment range according to the position sensor data to keep the hanger 6 in a relatively vertical state;

[0051] Since the steel truss arch bridge has not only an arch rib cantilever but also a tie beam below the arch rib cantilever, the tie beam is the bridge deck below the arch rib cantilever, and the tie beam is connected to the bottom of the arch rib cantilever by the hanger 6 to ensure its vertical force. After the position of the arch rib cantilever is adjusted through the above embodiment, it is easy to cause the tie beam below to tilt up, resulting in the joint of the tie beam being insufficient to install the last section of the steel truss 1 on the tie beam. Therefore, it is also necessary to adjust the joint of the tie beam. Since the hanger 6 is vertically connected to the bottom of the arch rib cantilever, the tie beam is connected to the bottom of the arch rib cantilever by the hanger 6 to ensure its vertical force. , used to connect the steel truss 1 on the arch rib cantilever and the steel truss 1 on the tie beam. Therefore, when adjusting the cable force of the sling 4 from bottom to top, it is necessary to maintain linkage with the position sensor. When the boom tilts beyond the preset value during adjustment of any sling 4, the sling 4 stops adjusting, and then the adjustments of other slings 4 are performed in sequence to ensure the vertical state of the boom 6 so that the steel truss 1 on the tie beam and the steel truss 1 on the arch rib cantilever can move synchronously. In order to ensure the verticality of the boom 6, detection is performed through a position sensor.

[0052] In one embodiment, after the last section of the steel truss 1 is installed on the arch rib cantilever on one side, the control device controls several tension groups to reversely execute the adjustment cycle, so that the arch rib cantilever on both sides is connected to the last section of the steel truss 1. Since the control device stores the adjustment amount data of each sling 4 in each adjustment cycle, the sling 4 can be gradually relaxed by reversing the adjustment cycle, so that the arch rib cantilever is put back. Since the last section of the steel truss 1 at the joint has been installed, a complete stable structure of the main span steel beam will be formed after the arch rib cantilever is gradually reset.

[0053] Because when the adjustment cycle is executed in reverse, after the arch rib cantilevers on both sides are completely against the force of the last steel truss 1, even if the sling 4 continues to release the cable force, the arch rib cantilever cannot be restored to the unadjusted state. Therefore, in order to improve the working rate, in one embodiment, when the adjustment cycle is executed in reverse, the cycle is stopped when the pressure sensor data no longer changes. When the pressure sensor data no longer changes, it can be said that the arch rib cantilevers on both sides have been fully installed in place.

[0054] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for erecting a steel truss arch bridge capable of actively adjusting the internal force and displacement of the entire bridge, characterized in that: The following steps are involved: Step 1: Erect steel trusses on the two main piers respectively, so that one end of the steel trusses is erected along the direction of the temporary pier to form a side span joint, and the other end is erected along the center of the two main piers to form an arch rib cantilever; Step 2: erect cable towers on the two main piers respectively, and continue to erect steel trusses along the arch rib cantilever, so that one end of a number of cables on the cable tower on the corresponding side is connected to a number of steel trusses as the steel trusses are erected, and the other end of the cable passes through the tower and is connected to the side span steel beam; Step 3: a pressure sensor is arranged between every two adjacent steel trusses, and the pressure sensor is arranged at the upper and lower ends of the contact position of the two adjacent steel trusses, and the pressure data of the corresponding steel trusses when they are connected is detected by the pressure sensor, and the pressure data is uploaded to the control device; Step 4: By adjusting the cable force of the sling tower crane, the cantilevers on both sides are lifted upward and the joint is expanded to be greater than or equal to the installation width of the last steel truss. At the same time, several slings adjust the cable force according to the pressure sensor data at different positions to make the force at different positions of the steel truss uniform; Step 5: Install the last steel truss beam at the joint opening to complete the joint; In the step 4, a plurality of slings at adjacent connection positions form a tension group, and the tension of the plurality of tension groups is adjusted in sequence from bottom to top according to the connection positions, and each tension adjustment is performed to keep the pressure difference of the pressure sensors at the upper and lower ends of the contact surface of each steel truss less than half of the limit value preset in the control device; A plurality of tension groups realize a cycle of cable force adjustment from bottom to top, which is called an adjustment cycle. The adjustment range of each cable force adjustment is controlled by a control device. The control device is preset with the number of adjustment cycles. After the number of adjustment cycles is reached, the plurality of tension groups stop adjusting the cable force. Distance sensors are respectively arranged on the steel trusses on both sides of the closure position, and the distance sensors are electrically connected to the control device. The distance sensors are used to detect the size of the closure. The control device is preset with a target distance. A plurality of tension groups implement a cycle of cable force adjustment from bottom to top, which is an adjustment cycle. When the cable force is adjusted cyclically for a number of adjustment cycles until the width of the closure reaches the target distance, the cycle is stopped.

2. A method for erecting a steel truss arch bridge capable of actively adjusting the internal force and displacement of the entire bridge according to claim 1, characterized in that: The cable force adjustment amount is gradually reduced according to the superposition of the adjustment cycle number until it is adjusted to reach the adjustment cycle number or the target distance.

3. The method for erecting a steel truss arch bridge capable of actively adjusting the internal force and displacement of the entire bridge according to claim 2 is characterized in that: The tie beam is connected to the bottom of the arch rib cantilever through a hanger. A position sensor is arranged on the arch rib cantilever. The position sensor is electrically connected to the control device. The detection area of ​​the position sensor is located on the tie beam and perpendicular to the bottom of the position sensor. Several tension groups correct the cable force adjustment range according to the position sensor data during the cyclic adjustment to keep the hanger in a relatively vertical state.

4. The method for erecting a steel truss arch bridge capable of actively adjusting the internal force and displacement of the entire bridge according to claim 2, characterized in that: After the last section of the steel truss is installed on the arch rib cantilever on one side, the control device controls the plurality of tension groups to reversely execute the adjustment cycle, so that the arch rib cantilever on both sides is connected with the last section of the steel truss.

5. The method for erecting a steel truss arch bridge capable of actively adjusting the internal force and displacement of the entire bridge according to claim 4, characterized in that: When the adjustment cycle is executed in reverse, the loop is stopped when the pressure sensor data no longer changes.

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