Post-tensioning prestressed beam tensioning device and method

Abstract

The present invention relates to the field of building and municipal construction technology, and in particular to a post-tensioned prestressed beam tensioning device and method. The post-tensioned prestressed beam tensioning device is used to apply pre-tensioning stress to a steel strand extending along a first direction, and includes a telescopic member, on which a plurality of sleeves sliding along the first direction are provided, each sleeve being sleeved on a steel strand, and a first clamping piece being provided between each sleeve and the corresponding steel strand so as to keep the sleeve and the steel strand relatively stationary, and a first chamber and a plurality of second chambers with variable volumes are provided in the telescopic member, the first chamber being connected to the plurality of second chambers respectively, and the volume change of the second chamber can drive the sleeve to slide on the telescopic member. When hydraulic oil is filled into the first chamber, the hydraulic oil in the first chamber enters the plurality of second chambers, and the change in pressure in the second chamber can cause the sleeve to drive the corresponding steel strand to straighten, and when the pressure in each second chamber is consistent, the straightening degree of the plurality of steel strands is consistent, thereby achieving pre-tightening.

Description

Technical Field

[0001] The present invention relates to the technical field of building and municipal construction, and in particular to a post-tensioning prestressed beam tensioning device and method. Background Art

[0002] Prestressing involves applying tension to a component in advance, causing it to undergo compressive stress and, in turn, deform to cope with the loads it is subjected to, including the component's own weight, wind loads, snow loads, and earthquake loads. Prestressing typically involves steel strands, jacks, anchor plates, and clips.

[0003] Before the engineering structural components are subjected to external loads, pre-tension stress is applied to the steel strands in the tension module to improve the bending resistance and rigidity of the components, delay the time for cracks to appear, and increase the durability of the components. When specifically applied in the construction field, the stored pre-stress will first offset the pre-stress in the concrete in the tension zone when the component is subjected to tension generated by external loads, and then the concrete will be stretched as the load increases, which limits the elongation of the concrete and delays or prevents the appearance of cracks. In the prior art, during the tensioning operation of steel strands, jacks are used to tension multiple steel strands. Although this can improve the operating efficiency, it is impossible to perform one-to-one operations on each steel strand, and it is easy to cause the problem of insufficient force application due to differences in the position and angle of the steel strands. Summary of the Invention

[0004] Based on this, it is necessary to provide a post-tensioning prestressed beam tensioning device and method to address the problem that the current tensioning equipment easily applies inconsistent force to each steel strand.

[0005] The above purpose is achieved through the following technical solutions:

[0006] A post-tensioned prestressed beam tensioning device is used to apply pre-tensioning stress to multiple steel strands extending along a first direction on a box beam, including a pre-tensioning mechanism, a tensioning mechanism and a positioning mechanism. The pre-tensioning mechanism includes a telescopic member, the box beam and the telescopic member are arranged along the first direction, and a first chamber is provided in the telescopic member; multiple steel strands pass through the telescopic member along the first direction and are slidably connected to the telescopic member, each steel strand is respectively provided with a sleeve that slides along the first direction, the sleeve is slidably arranged on the telescopic member, and a second chamber with a variable volume is provided between each sleeve and the telescopic member, and the second chamber has a second chamber with a variable volume. The chamber is connected to the first chamber, and the first chamber and the second chamber are filled with hydraulic oil. When the hydraulic oil is filled into the second chamber through the first chamber, the hydraulic oil can push the casing away from the box beam; a first clamp is provided between each casing and the corresponding steel strand, which can make the casing and the steel strand relatively stationary in the first direction; the tensioning mechanism is arranged between the box beam and the telescopic member, which can control the volume of the first chamber to decrease when the casing and the corresponding steel strand are relatively stationary, and tension multiple steel strands; the positioning mechanism is used to clamp and position multiple tensioned steel strands.

[0007] Preferably, the tensioning mechanism includes a hydraulic cylinder, a mounting plate and a first power group. The hydraulic cylinder is arranged between the box girder and the telescopic member. The mounting plate is arranged on the hydraulic cylinder. The mounting plate is provided with a plurality of first through holes penetrating the mounting plate along a first direction. Each steel strand passes through the mounting plate and is located in one of the first through holes. A second clip and a first wedge block are provided in each first through hole. The second clip is slidingly arranged on the mounting plate along the radial direction of the corresponding steel strand, and the second clip slides and abuts against the steel strand. The first wedge block is movably arranged on the mounting plate for controlling the abutment force between the second clip and the steel strand. The first power group is used to provide power for the movement of the first wedge block.

[0008] Preferably, the first power group includes a first push cylinder, which is slidably arranged on the telescopic member along the first direction. The first push cylinder is located on the side of the first wedge block away from the box beam and is slidably connected to the first wedge block. A third chamber containing hydraulic oil and with a variable volume is provided between the first push cylinder and the telescopic member. The first push cylinder can change the volume of the third chamber by sliding on the telescopic member; the telescopic member telescopes along the first direction, and when the telescopic member is extended or shortened, the volume of the first chamber decreases or increases; a flow channel is provided in the telescopic member, which is connected to the first chamber and the third chamber respectively, and a pressure valve is provided in the flow channel.

[0009] Preferably, the positioning mechanism includes an anchor plate, an anchor cylinder, a second power group and a positioning assembly, the anchor plate is arranged on the box girder, the anchor cylinder is provided with a plurality of second through holes that pass through the anchor cylinder along a first direction, a plurality of steel strands pass through the anchor cylinder and are respectively located in a second through hole, a third clip and a second wedge are provided in each second through hole, the third clip is slidably arranged on the anchor cylinder along the radial direction of the corresponding steel strand, and the third clip slides and abuts against the steel strand, the second wedge is movably arranged on the anchor cylinder for controlling the abutment force between the third clip and the steel strand, the second power group provides power for the movement of the second wedge; the positioning assembly is used to limit the third clip abutting against the steel strand.

[0010] Preferably, a grouting port is provided on the anchor plate.

[0011] Preferably, each of the first clip, the second clip and the third clip includes a plurality of arc plates, and when the projections of the plurality of arc plates in the first direction are concentric, a distance is provided between two adjacent arc plates around the first direction.

[0012] Preferably, a side of the arc plate in the first clamp, the second clamp and the third clamp close to the corresponding steel strand is provided with a spiral groove having a rotation direction opposite to that of the steel strand.

[0013] Preferably, the number of positioning components is consistent with the number of second through holes, each positioning component is correspondingly arranged in one of the second through holes, each positioning component includes a clamping block, the number of arc plates in the clamping block and the third clip is consistent, multiple clamping blocks are arranged around the circumferential direction of the steel strand in the corresponding second through hole, the clamping blocks are slidably arranged on the anchor tube along the radial direction of the steel strand, and a spring is provided between each clamping block and the anchor tube for driving the clamping block to approach the steel strand, and the clamping block is clamped with the third clip in the first direction.

[0014] Preferably, the hydraulic cylinder is provided with a lifting lug.

[0015] An embodiment of the present invention further provides a post-tensioning prestressed beam tensioning method, comprising the following steps:

[0016] S1, place the steel strands into the prefabricated box girder and pass the steel strands through the sleeves on the telescopic members.

[0017] S2, use the first clamp to connect the casing and the steel strand together.

[0018] S3, filling the first chamber with hydraulic oil until the pressures in the plurality of second chambers are the same, thereby completing the pre-tightening of the steel strands.

[0019] S4, start the tensioning mechanism to tension the pre-tightened steel strands.

[0020] S5, start the positioning mechanism to position the tensioned steel strand.

[0021] The beneficial effects of the present invention are as follows: a first chamber and multiple second chambers are connected to each other on the telescopic member. When hydraulic oil is filled into the first chamber, the hydraulic oil in the first chamber flows into the multiple second chambers, thereby increasing the volume of the second chambers and causing the multiple sleeves to drive the corresponding steel strands to straighten along the first direction. If one steel strand is straightened first, the hydraulic oil in the first chamber will flow into the other second chambers, causing the other sleeves to continue to drive the corresponding steel strands to straighten until all steel strands in the same group are straightened. This achieves pre-tightening of the multiple steel strands in the same group, ensuring that the multiple steel strands in the same group are subjected to basically the same force during tensioning. At the same time, it reduces manual operation procedures, improves the degree of automation, and saves time and effort. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic structural diagram of a post-tensioning prestressed beam tensioning device provided by an embodiment of the present invention;

[0023] Figure 2 A front view of a post-tensioning prestressed beam tensioning device provided by an embodiment of the present invention;

[0024] Figure 3 for Figure 2 Cross-sectional view along the AA axis;

[0025] Figure 4 for Figure 3 Enlarged view of point B in the middle;

[0026] Figure 5 for Figure 4 Enlarged view of point C in the middle;

[0027] Figure 6 for Figure 3 Enlarged view of point D in the middle;

[0028] Figure 7 An exploded view of a positioning mechanism of a post-tensioned prestressed beam tensioning device provided in an embodiment of the present invention.

[0029] in:

[0030] 100, first chamber; 101, second chamber; 102, first clip; 103, sleeve; 104, slide; 105, pull cylinder; 106, cylinder; 107, guide cylinder; 108, piston rod; 109, mounting plate; 110, first through hole; 111, second clip; 112, first wedge; 113, first push cylinder; 114, third chamber; 115, second through hole; 116, The third clamp; 117, the second wedge block; 118, the fixing cylinder; 119, the second push cylinder; 120, the channel; 121, the anchor plate; 122, the anchor cylinder; 123, the fourth chamber; 124, the block; 125, the spring piece; 126, the receiving groove; 127, the groove; 128, the flow channel; 129, the pressure valve; 200, the box beam; 201, the grouting port; 202, the lifting lug; 203, the steel strand. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0032] The serial numbers assigned to components herein, such as "first," "second," etc., are used solely to distinguish the objects being described and do not convey any sequential or technical meaning. References to "connection" and "coupling" herein, unless otherwise specified, include both direct and indirect connections (couplings). In the description of the present invention, it should be understood that terms such as "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise" indicate positions or relationships based on those shown in the accompanying drawings. These terms are intended solely to facilitate the description of the present invention and simplify the description. They are not intended to indicate or imply that the device or component being referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0033] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0034] like Figures 1 to 7As shown, an embodiment of the present invention provides a post-tensioning prestressed beam tensioning device for applying prestress to a plurality of steel strands 203 extending along a first direction on a box beam 200, comprising a pre-tensioning mechanism, a tensioning mechanism, and a positioning mechanism. The pre-tensioning mechanism comprises a telescopic member, the box beam 200 and the telescopic member are arranged along the first direction, and a first chamber 100 is provided in the telescopic member. The plurality of steel strands 203 are divided into a plurality of groups, each group having a plurality of steel strands 203. The plurality of steel strands 203 in each group pass through the telescopic member along the first direction and are slidably connected to the telescopic member. Each steel strand 203 is sleeved with a sleeve 103 that slides along the first direction. The sleeve 103 is slidably arranged on the telescopic member, and a second chamber 101 with a variable volume is provided between each sleeve 103 and the telescopic member. The second chamber 101 is connected to the first chamber 100, and the first chamber 100 and the second chamber 101 are filled with hydraulic oil. When hydraulic oil is filled into the second chamber 101 through the first chamber 100, the hydraulic oil pushes the sleeves 103 away from the box girder 200. A first clamp 102 is provided between each sleeve 103 and the corresponding steel strand 203, enabling the sleeve 103 and the corresponding steel strand 203 to remain stationary relative to each other in a first direction. A tensioning mechanism is disposed between the box girder 200 and the telescopic member. This mechanism controls the volume of the first chamber 100 to decrease when the sleeves 103 and the corresponding steel strand 203 are stationary, thereby tensioning the multiple steel strands 203 in the same group. A positioning mechanism is used to clamp and position the multiple steel strands 203 in the same group after tensioning.

[0035] Specifically, there are multiple first clips 102 between each sleeve 103 and the corresponding steel strand 203. The multiple first clips 102 are located on the side of the sleeve 103 away from the box girder 200. The multiple first clips 102 can be combined to form an annular tube that encloses the steel strand 203. When the multiple first clips 102 are in contact with the steel strand 203, a gap is provided between adjacent first clips 102. An inclined surface is provided at one end of the sleeve 103 close to the first clamp 102, and the inclined surface gradually approaches the axis of the sleeve 103 from the end of the sleeve 103 to the direction close to the box beam 200. Each first clamp 102 is provided with an inclined surface adapted to the sleeve 103. After multiple first clamps 102 come into contact with the steel strand 203, they can enter the sleeve 103 and be slidably connected with the inclined surface on the sleeve 103. When the sleeve 103 gradually approaches the first clamp 102, a force in the radial direction of the sleeve 103 is applied to the first clamp 102 through the inclined surface, so that the friction between the multiple first clamps 102 and the steel strand 203 increases after squeezing the steel strand 203. At the same time, the friction between the first clamp 102 and the sleeve 103 will also gradually increase until the two no longer slide relative to each other.

[0036] A step is provided on the circumferential surface of the sleeve 103, which slides in the second chamber 101 and is located on the side of the second chamber 101 away from the box beam 200. When the hydraulic oil in the second chamber 101 increases, the hydraulic oil can push the sleeve 103 away from the box beam 200 in the first direction through the step.

[0037] A first chamber 100 and a plurality of second chambers 101 are connected to each other on the telescopic member. When hydraulic oil is filled into the first chamber 100, the hydraulic oil in the first chamber 100 flows into the plurality of second chambers 101, thereby increasing the volume of the second chamber 101 and causing the plurality of sleeves 103 to drive the corresponding steel strands 203 to straighten along the first direction. If one of the steel strands 203 is straightened first, the hydraulic oil in the first chamber 100 will flow into the other second chambers 101, causing the other sleeves 103 to continue to drive the corresponding steel strands 203 to straighten until all the steel strands 203 in the same group are straightened. This achieves pre-tightening of the plurality of steel strands 203 in the same group, ensuring that the plurality of steel strands 203 in the same group are subjected to substantially the same force during tensioning. This reduces manual operation procedures, improves the degree of automation, and saves time and effort.

[0038] In this embodiment, the tensioning mechanism includes a hydraulic cylinder, a mounting plate 109 and a first power group. The hydraulic cylinder is arranged between the box girder 200 and the telescopic member. The mounting plate 109 is arranged on the hydraulic cylinder. The mounting plate 109 is provided with a plurality of first through holes 110 that pass through the mounting plate 109 along the first direction. Each steel strand 203 of the same group passes through the mounting plate 109 and is located in one of the first through holes 110. A second clamp 111 and a first wedge block 112 are provided in each first through hole 110. The second clamp 111 is slidably arranged on the mounting plate 109 along the radial direction of the corresponding steel strand 203, and the second clamp 111 slides and abuts against the steel strand 203. The first wedge block 112 is movably arranged on the mounting plate 109 for controlling the abutment force between the second clamp 111 and the steel strand 203. The first power group is used to provide power for the movement of the first wedge block 112.

[0039] Specifically, the hydraulic cylinder includes a cylinder body 106, a guide cylinder 107, and a piston rod 108. The cylinder body 106 is disposed between the box beam 200 and the telescopic member. The guide cylinder 107 is disposed within the cylinder body 106 along a first direction, and one end of the guide cylinder 107 is connected to the cylinder body 106. One end of the piston rod 108 is disposed within the cylinder body 106 and sleeved on the guide cylinder 107. The piston rod 108 and the guide cylinder 107 are slidably connected. One end of the piston rod 108, located within the cylinder body 106, divides the cylinder body 106 into two mutually isolated oil chambers. The other end of the piston rod 108 passes through the cylinder body 106 and is connected to the telescopic member. By alternately supplying and withdrawing oil from the two oil chambers, the piston rod 108 slides relative to the cylinder body 106 in the first direction. The piston rod 108 sliding relative to the cylinder body 106 can drive the telescopic member to move or, when there is no relative movement between the sleeve 103 and the corresponding first clamp 102, push the telescopic member to retract.

[0040] The second clip 111 and the first wedge block 112 move away from the steel strand 203 in sequence along the radial direction of the steel strand 203, and the first wedge block 112 is slidably connected to the second clip 111 and the mounting plate 109 respectively. The contact surface of the first wedge block 112 and the second clip 111 is parallel to the first direction, and the first through hole 110 is a conical hole. The large end of the first through hole 110 is closer to the telescopic member than its small end. The side of the first wedge block 112 that slides in contact with the mounting plate 109 is adapted to the conical surface of the first through hole 110. The first power group controls the first wedge block 112 to approach the mounting plate 109, so that the first wedge block 112 can move along the first direction and the radial direction of the steel strand 203. The moving first wedge block 112 drives the second clip 111 to abut against the steel strand 203 along the radial direction of the steel strand 203, so that the second clip 111 fixes the steel strand 203.

[0041] After multiple sleeves 103 drive the corresponding first clamps 102 to pre-tighten the corresponding steel strands 203, the first power group can push the first wedge 112 to make the second clamp 111 abut against the corresponding steel strand 203. At this time, the steel strand 203 that needs to be tensioned is located on the side of the second clamp 111 away from the telescopic member. When the second clamp 111 clamps the steel strand 203, the second clamp 111 applies force to the steel strand 203 from the radial direction of the steel strand 203, and will not change the position of the steel strand 203 in the first direction, so that the length of the steel strand 203 that needs to be tensioned is consistent, that is, in the tensioning process, the problem of substandard force application caused by inconsistent elongation of multiple steel strands 203 in the same group is effectively avoided.

[0042] In this embodiment, the first power group includes a first push cylinder 113, which is slidably arranged on the telescopic member along the first direction. The first push cylinder 113 is located on the side of the first wedge block 112 away from the box beam 200 and is slidably connected to the first wedge block 112. A third chamber 114 containing hydraulic oil and with a variable volume is provided between the first push cylinder 113 and the telescopic member. The first push cylinder 113 slides on the telescopic member to change the volume of the third chamber 114; the telescopic member telescopes along the first direction, and when the telescopic member is extended or shortened, the volume of the first chamber 100 decreases or increases; a flow channel 128 is provided in the telescopic member, and the flow channel 128 is respectively connected to the first chamber 100 and the third chamber 114, and a pressure valve 129 is provided in the flow channel 128.

[0043] Specifically, the telescopic part includes a slide 104 and a pull cylinder 105. One end of the slide 104 is arranged on the end of the cylinder body 106 away from the box beam 200, and the other end of the slide 104 is slidably inserted into the pull cylinder 105. The first chamber 100 and the second chamber 101 are located on the pull cylinder 105, and the third chamber 114 is located on the slide 104. The flow channel 128 is arranged on the slide 104 and passes through the end of the slide 104 close to the pull cylinder 105.

[0044] The threshold value of the pressure valve 129 is greater than the oil pressure required to straighten multiple steel strands 203 in the same group. When the telescopic member contracts and the hydraulic oil in the first chamber 100 flows into the multiple second chambers 101, the volume of the second chamber 101 corresponding to the straightened steel strands 203 no longer changes, and the hydraulic oil in the first chamber 100 flows into the second chamber 101 corresponding to the unstraightened steel strands 203, so that all the steel strands 203 are straightened. At this time, the oil pressure in the first chamber 100 and the multiple second chambers 101 are equal. As the telescopic member continues to contract, the oil pressure in the first chamber 100 increases and exceeds the threshold value of the pressure valve 129. The oil pressure in the first chamber 100 will flow into the third chamber 114, so that the second clamp 111 clamps the corresponding steel strands 203. After the steel strand 203 is tightened and no obvious deformation occurs, the steel strand 203 is clamped and positioned so that the force and stretching amount of the steel strand 203 are as consistent as possible during the subsequent tensioning process, thereby reducing errors.

[0045] In this embodiment, the box girder 200 is provided with a plurality of channels 120 for installing the same group of steel strands 203, and the positioning mechanism includes an anchor plate 121, an anchor tube 122, a second power group and a positioning assembly. The anchor plate 121 is arranged on the box girder 200 and is located at the channel 120. The anchor tube 122 is provided with a plurality of second through holes 115 that pass through the anchor tube 122 along the first direction. The plurality of steel strands 203 in the same group pass through the anchor tube 122 and are respectively located in a second through hole 115. A third clip 116 and a second wedge block 117 are provided in each second through hole 115. The third clip 116 is slidably arranged on the anchor tube 122 along the radial direction of the corresponding steel strand 203, and is used to control the size of the abutment force between the third clip 116 and the steel strand 203. The second power group provides power for the movement of the second wedge block 117; the positioning assembly is used to limit the third clip 116 that abuts against the steel strand 203.

[0046] Specifically, the third clip 116 and the second wedge 117 successively move away from the steel strand 203 in the radial direction of the steel strand 203. The second wedge 117 is slidably connected to the third clip 116 and the anchor tube 122, respectively. The contact surface between the second wedge 117 and the third clip 116 extends along the first direction. The second through hole 115 is a tapered hole. The large end of the second through hole 115 is closer to the telescopic member than the small end. The surface of the second wedge 117 in sliding contact with the anchor tube 122 matches the tapered surface of the second through hole 115. After the steel strand 203 is tensioned, the second power unit controls the second wedge 117 to move along the first direction and the radial direction of the steel strand 203. The moving second wedge 117 drives the third clip 116 to abut against the steel strand 203, so that the third clip 116 fixes the tensioned steel strand 203.

[0047] The second power group includes a fixed cylinder 118 and a second push cylinder 119. The fixed cylinder 118 is arranged on the cylinder body 106 and extends along the first direction. Multiple steel strands 203 in the same group pass through the inside of the fixed cylinder 118 and are slidably connected to the fixed cylinder 118. The fixed cylinder 118 is arranged between the anchor cylinder 122 and the cylinder body 106. The fixed cylinder 118 is sleeved on the anchor cylinder 122, and the fixed cylinder 118 is slidably connected to the anchor cylinder 122 along the first direction and can abut in the first direction for positioning the cylinder body 106. The second push cylinder 119 is slidably arranged on the fixed cylinder 118 along the first direction, and the second push cylinder 119 can slide and abut against the third clamp 116. A fourth chamber 123 with a variable volume is provided between the second push cylinder 119 and the fixed cylinder 118. Hydraulic oil can also be added to the fourth chamber 123, and the hydraulic oil can control the volume of the fourth chamber 123. The fourth chamber 123 is located on the side of the fixed cylinder 118 away from the third clamp 116.

[0048] In this embodiment, a grouting port 201 is provided on the anchor plate 121. The anchor plate 121 and the anchor tube 122 can seal the channel 120 on the box beam 200, and grouting can be injected into the sealed channel 120 through the grouting port 201.

[0049] In this embodiment, each of the first clip 102 , the second clip 111 and the third clip 116 includes a plurality of arc plates. When the projections of the plurality of arc plates in the first direction are concentric, a distance is provided between two adjacent arc plates in the first direction.

[0050] Specifically, when the multiple arc plates in the first clamp 102, the second clamp 111 or the third clamp 116 are concentric, the multiple arc plates can also approach each other. After approaching each other, the multiple arc plates will no longer be concentric. When the multiple arc plates clamp the steel strand 203, the steel strand 203 is not easily squeezed into the gap between two adjacent arc plates.

[0051] In this embodiment, the arc plates in the first clip 102, the second clip 111 and the third clip 116 are each provided with a spiral groove having a rotation direction opposite to that of the steel strand 203 on one side thereof close to the corresponding steel strand 203. The provision of the spiral groove can increase the friction between the second clip 111 and the steel strand 203, making it less likely for relative sliding to occur between the second clip 111 and the steel strand 203.

[0052] In this embodiment, the number of positioning components is consistent with the number of second through holes 115, and each positioning component is correspondingly arranged in one of the second through holes 115. Each positioning component includes a block 124, and the number of arc plates in the block 124 and the third clamp 116 is consistent. Multiple blocks 124 are arranged around the circumferential direction of the steel strand 203 in the corresponding second through hole 115. The blocks 124 are slidably arranged on the anchor tube 122 along the radial direction of the steel strand 203. A spring 125 for driving the block 124 to approach the steel strand 203 is provided between each block 124 and the anchor tube 122, and the block 124 is clamped with the third clamp 116 in the first direction.

[0053] Specifically, multiple groups of receiving grooves 126 are provided on the anchor tube 122, and each group of receiving grooves 126 has multiple numbers. The multiple receiving grooves 126 in the same group are arranged along the circumferential direction of the steel strand 203, and each receiving groove 126 is connected to the corresponding second through hole 115. Each block 124 is slidably set in one of the receiving grooves 126, and the spring piece 125 is located in the receiving groove 126. A groove 127 is provided on the side of the second wedge block 117 away from the third clamp 116, and chamfers are provided on the block 124 and the second wedge block 117. When the second wedge block 117 approaches the block 124 and contacts the block 124, the second wedge block 117 will push the block 124 to slide in the accommodating groove 126 and away from the steel strand 203 through the cooperation between itself and the chamfer on the block 124. When the groove 127 on the second wedge block 117 moves to the middle of the block 124 and the steel strand 203, the block 124 will be inserted into the groove 127 under the action of the spring piece 125, thereby limiting the sliding of the second wedge block 117 in the first direction.

[0054] The side of the block 124 close to the box beam 200 is a slope, and the slope on the block 124 gradually approaches the box beam 200 from the side close to the steel strand 203 to the side away from the steel strand 203. The groove 127 is provided with a slope that is compatible with the slope on the block 124. When the block 124 and the groove 127 are matched, they will have a barb effect, which can increase the stability of the connection between the block 124 and the second wedge block 117.

[0055] In this embodiment, a lifting lug 202 is provided on the hydraulic cylinder, and the hydraulic cylinder can be lifted by the lifting lug 202, thereby reducing manual labor intensity and better maintaining the position of the hydraulic cylinder.

[0056] Specifically, an oil injection device is provided outside the cylinder body 106 , and the oil injection device can inject or extract oil into the first chamber 100 , the two oil chambers in the cylinder body 106 and the fourth chamber 123 .

[0057] The working principle of the post-tensioning prestressed beam tensioning device provided in the above embodiment is as follows:

[0058] First, pass the steel strand 203 through the box girder 200, then pass the anchor plate 121 through the steel strand 203 and install it on the box girder 200, then install the anchor cylinder 122 on the anchor plate 121, and then pass the steel strand 203 through the fixed cylinder 118, the guide cylinder 107, the piston rod 108, the sliding cylinder 104 and the casing 103 in the first direction in sequence.

[0059] Then push the cylinder body 106 toward the box beam 200. Before the cylinder body 106 drives the fixing cylinder 118 to move and contact the anchor cylinder 122, place the third clip 116 into the second through hole 115. Then push the cylinder body 106 so that the fixing cylinder 118 is sleeved on the anchor cylinder 122 and abuts against the anchor cylinder 122. At this time, the second push cylinder 119 abuts against the third clip 116, so that the position of the third clip 116 is relatively stable. Then the first clamp 102 is placed in the sleeve 103, and the second chamber 101 is in a smaller state. The sleeve 103 is connected to the steel strand 203 through the first clamp 102, and there is friction between them. Then oil is injected into the first chamber 100 through the oil injection device, and the first chamber 100 increases or the hydraulic oil in the first chamber 100 flows into the second chamber 101. The increase in the first chamber 100 will cause the pull cylinder 105 to move away from the slide cylinder 104, thereby driving the steel strand 203 to slide through the sleeve 103 and the first clamp 102, or the hydraulic oil entering the second chamber 101 will push the sleeve 103 away from the slide cylinder 104 along the first direction, and the sleeve 103 drives the steel strand 203 to slide through the first clamp 102. When one of the steel strands 203 is straightened, it means that the tension on the steel strand 203 is greater than the tension on the unstraightened steel strand 203. The hydraulic oil in the first chamber 100 will flow to the other second chamber 101, straightening the unstraightened steel strand 203.

[0060] After all the steel strands 203 are straightened, the pressure in each second chamber 101 is consistent. At this point, hydraulic oil continues to be injected into the first chamber 100, increasing the pressure in both the first and second chambers 100, 101. When the pressure in the first chamber 100 increases to exceed the threshold of the pressure valve 129, the pressure valve 129 opens, and the hydraulic oil in the first chamber 100 enters the flow channel 128 through the pressure valve 129, and then enters the third chamber 114. The hydraulic oil entering the third chamber 114 pushes the first push cylinder 113 toward the box girder 200. The first push cylinder 113 pushes the first wedge block 112 to move synchronously. At the same time, guided by the first through hole 110, the first wedge block 112 approaches the steel strand 203 in the radial direction. The first push cylinder 113 and the first wedge block 112 slide relative to each other, and the first wedge block 112, approaching the steel strand 203, pushes the second clamp 111 into contact with the steel strand 203. As the hydraulic oil in the first chamber 100 increases, the clamping force of the second clamping piece 111 on the steel strand 203 increases.

[0061] Then, the oil pressure in the first chamber 100 is maintained and oil is injected into one of the oil chambers in the cylinder body 106 through the oil injection device, so that the piston rod 108 moves away from the box beam 200 relative to the cylinder body 106. The piston rod 108 drives the telescopic member and the second clamp 111 to move, and the second clamp 111 clamps the steel strand 203 to move, and the steel strand 203 is stretched.

[0062] After the steel strand 203 is stretched, hydraulic oil is filled into the fourth chamber 123 through the oil injection device. The increase in hydraulic oil in the fourth chamber 123 causes the second push cylinder 119 to slide relative to the fixed cylinder 118 toward the box girder 200. The second push cylinder 119 pushes the second wedge block 117 to slide on the anchor cylinder 122. Guided by the conical surface of the second through hole 115, the second wedge block 117 pushes the third clamp 116 toward the steel strand 203. The third clamp 116 clamps the steel strand 203 in the radial direction of the steel strand 203. When the second wedge block 117 slides toward the box girder 200 along the first direction, the second wedge block 117 contacts the clamping block 124. At the same time, with the cooperation of the inclined surfaces of the second wedge block 117 and the clamping block 124, the second wedge block 117 pushes the clamping block 124 to move in the receiving groove 126 away from the steel strand 203. The clamping block 124 pushes the spring piece 125 to deform, and the spring piece 125 begins to accumulate force. When the groove 127 on the second wedge block 117 moves to the center between the clamping block 124 and the third clamping piece 116, the clamping block 124 extends out of the receiving slot 126 under the action of the spring piece 125 and slides into the groove 127. At this point, the second wedge block 117 no longer moves in the second direction, and the third clamping piece 116 also clamps the steel strand 203.

[0063] Next, the hydraulic oil in the first chamber 100 is extracted through the oil injection device. The hydraulic oil in the first chamber 100 decreases, and the volume of the first chamber 100 also decreases. The telescopic member contracts and drives the sleeve 103 to move relative to the steel strand 203. The sleeve 103 separates from the first clamp 102, and the hydraulic oil in the first chamber 100 continues to be extracted until the pressure valve 129 opens again. The hydraulic oil in the third chamber 114 flows into the first chamber 100 through the flow channel 128. The interior of the third chamber 114 presents a negative pressure. The first push cylinder 113 moves away from the second clamp 111 under the negative pressure environment. At the same time, the first push cylinder 113 drives the first wedge 112 to move synchronously, and the second clamp 111 no longer clamps the steel strand 203. The hydraulic cylinder is then removed from the steel strand 203, and the piston rod 108 and the second push cylinder 119 are reset through the oil injection device.

[0064] Finally, the excess steel strands 203 are cut off and grouting is injected into the channel 120 through the grouting port 201 .

[0065] An embodiment of the present invention further provides a post-tensioning prestressed beam tensioning method, comprising the following steps:

[0066] S1, place the steel strand 203 into the prefabricated box girder 200, and pass the steel strand 203 through the sleeve 103 on the telescopic member; the box girder 200 is provided with a plurality of channels 120 for the steel strand 203 to pass through, and each group of steel strands 203 passes through a corresponding channel 120, and the end of the steel strand 203 is located outside the channel 120 and the steel strand 203 passing through the channel 120 is inserted into the corresponding sleeve 103.

[0067] S2, use the first clamp 102 to connect the sleeve 103 and the steel strand 203 together; through the cooperation between the first clamp 102 and the sleeve 103, push the sleeve 103 to make it close to the first clamp 102, and the multiple arc plates in the first clamp 102 gradually approach each other under the guidance of the inclined surface of the sleeve 103. After approaching, the first clamp 102 will contact the steel strand 203. As the contact force between the first clamp 102 and the steel strand 203 increases, the friction between them will also increase, and the sleeve 103 and the steel strand 203 can move synchronously in the direction away from the box girder 200.

[0068] S3, fill the first chamber 100 with hydraulic oil until the pressure in multiple second chambers 101 is consistent, completing the pre-tightening of the steel strand 203; inject oil into the first chamber 100 through an external oil injection device, and the excess hydraulic oil in the first chamber 100 flows into the second chamber 101. The sleeve 103 in the second chamber 101 drives the steel strand 203 away from the box girder 200 under the action of the hydraulic oil, and the steel strand 203 is gradually tightened. The volume of the second chamber 101 corresponding to the tightened steel strand 203 will no longer increase before the steel strands 203 in other second chambers 101 are tightened.

[0069] S4, start the tensioning mechanism to tension the pre-tightened steel strands 203; after all the steel strands 203 are tightened, the lengths of the steel strands 203 in the channel 120 are consistent and the tension they bear is consistent. At this time, the steel strands 203 are fixed again by the second clips 111, and the distances between the multiple second clips 111 and the box beam 200 are consistent, ensuring that the tensions received by the steel strands 203 in the channel 120 during tensioning are basically consistent.

[0070] S5: The positioning mechanism is activated to position the tensioned steel strands 203. After tensioning, the steel strands 203 are secured using the third clamping piece 116. The third clamping piece 116 is located between the box girder 200 and the second clamping piece 111. When the third clamping piece 116 contacts the corresponding steel strand 203, it does not slide relative to the steel strand 203 in the first direction. After the tension on the steel strand 203 is removed, the steel strand 203 in the channel 120 does not shrink, and a good tensioning force is still maintained.

[0071] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0072] The above-described embodiments merely illustrate several embodiments of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A post-tensioning prestressed beam tensioning device for applying prestressing stress to a plurality of steel strands extending along a first direction on a box beam, characterized in that: include: A pre-tensioning mechanism, a tensioning mechanism and a positioning mechanism, wherein the pre-tensioning mechanism includes a telescopic member, the box beam and the telescopic member are arranged along a first direction, and a first chamber is provided in the telescopic member; A plurality of steel strands pass through the telescopic member along a first direction and are slidably connected to the telescopic member, each steel strand is respectively sleeved with a sleeve that slides along the first direction, the sleeve is slidably arranged on the telescopic member, and a second chamber with a variable volume is provided between each sleeve and the telescopic member, the second chamber is communicated with the first chamber, and the first chamber and the second chamber are filled with hydraulic oil, and when the hydraulic oil is filled into the second chamber through the first chamber, the hydraulic oil can push the sleeve away from the box beam; a first clamping piece is provided between each sleeve and the corresponding steel strand, which can make the sleeve and the steel strand relatively stationary in the first direction; a tensioning mechanism is provided between the box beam and the telescopic member, which can control the volume of the first chamber to decrease when the sleeve and the corresponding steel strand are relatively stationary, and tension the plurality of steel strands; the positioning mechanism is used to clamp and position the plurality of tensioned steel strands; The tensioning mechanism includes a hydraulic cylinder, a mounting plate and a first power group, the hydraulic cylinder is arranged between the box girder and the telescopic member, the mounting plate is arranged on the hydraulic cylinder, a plurality of first through holes are provided on the mounting plate that penetrate the mounting plate along a first direction, each steel strand penetrates the mounting plate and is located in one of the first through holes, a second clip and a first wedge are provided in each first through hole, the second clip is slidably arranged on the mounting plate along the radial direction of the corresponding steel strand, and the second clip slides and abuts against the steel strand, the first wedge is movably arranged on the mounting plate, and is used to control the abutment force between the second clip and the steel strand, and the first power group is used to provide power for the movement of the first wedge; The first power group includes a first push cylinder, which is slidingly arranged on the telescopic member along the first direction. The first push cylinder is located on the side of the first wedge block away from the box beam and is slidably connected to the first wedge block. A third chamber containing hydraulic oil and with a variable volume is provided between the first push cylinder and the telescopic member. The first push cylinder can change the volume of the third chamber by sliding on the telescopic member; the telescopic member is telescopic and retracts along the first direction, and when the telescopic member is extended or shortened, the volume of the first chamber decreases or increases; a flow channel is provided in the telescopic member, which is connected to the first chamber and the third chamber respectively, and a pressure valve is provided in the flow channel.

2. The post-tensioning prestressed beam tensioning equipment according to claim 1, characterized in that: The positioning mechanism includes an anchor plate, an anchor cylinder, a second power group and a positioning assembly. The anchor plate is arranged on the box girder. The anchor cylinder is provided with a plurality of second through holes that penetrate the anchor cylinder along a first direction. A plurality of steel strands penetrate the anchor cylinder and are respectively located in a second through hole. A third clip and a second wedge are provided in each second through hole. The third clip is slidably arranged on the anchor cylinder along the radial direction of the corresponding steel strand, and the third clip slides and abuts against the steel strand. The second wedge is movably arranged on the anchor cylinder for controlling the abutting force between the third clip and the steel strand. The second power group provides power for the movement of the second wedge; the positioning assembly is used to limit the third clip abutting against the steel strand.

3. The post-tensioning prestressed beam tensioning equipment according to claim 2, characterized in that: A grouting port is provided on the anchor plate.

4. The post-tensioning prestressed beam tensioning equipment according to claim 2, characterized in that: Each of the first clip, the second clip and the third clip includes a plurality of arc plates. When the projections of the plurality of arc plates in the first direction are concentric, a distance is provided between two adjacent arc plates along the first direction.

5. The post-tensioning prestressed beam tensioning equipment according to claim 4, characterized in that: A spiral groove having a rotation direction opposite to that of the steel strand is provided on one side of the arc plates in the first clamping piece, the second clamping piece and the third clamping piece, which is close to the corresponding steel strand.

6. The post-tensioning prestressed beam tensioning equipment according to claim 2, characterized in that: The number of positioning components is consistent with the number of second through holes, and each positioning component is correspondingly arranged in one of the second through holes. Each positioning component includes a card block, and the number of arc plates in the card block and the third clip is consistent. Multiple card blocks are arranged in the circumferential direction of the steel strand in the corresponding second through hole, and the card blocks are slid on the anchor tube along the radial direction of the steel strand. A spring is provided between each card block and the anchor tube for driving the card block to approach the steel strand, and the card block is clamped with the third clip in the first direction.

7. The post-tensioning prestressed beam tensioning equipment according to claim 1, characterized in that: The hydraulic cylinder is provided with lifting lugs.

8. A post-tensioning prestressed beam tensioning method, using the post-tensioning prestressed beam tensioning device according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, placing the steel strands into the prefabricated box girder and passing the steel strands through the sleeves on the telescopic members; S2, using the first clamp to connect the casing and the steel strand together; S3, filling the first chamber with hydraulic oil until the pressure in the plurality of second chambers is uniform, thereby completing the pre-tightening of the steel strands; S4, starting the tensioning mechanism to tension the pre-tightened steel strands; S5, start the positioning mechanism to position the tensioned steel strand.

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