Adjustable steel support device for portal openings of cast-in-place box girders

Abstract

This application relates to the field of building construction technology and provides an adjustable steel support device for a cast-in-place box girder portal opening, including a supporting steel column, a supporting keel, a flange truss, and a cast-in-place box girder; the supporting keel includes a main keel, a longitudinal bridge keel, and a transverse bridge keel; an adjustable keel lateral resistance component is provided at the upper end of the main keel and on one side of the longitudinal bridge keel; the adjustable keel lateral resistance component includes: a slide rail, a clamp, a sliding sleeve, a locking element, a damping element, and a connecting seat; the slide rail is fixed to the upper end of the main keel by the clamp; the sliding sleeve is fitted onto the upper end of the slide rail and is movably engaged; the locking element restricts the movable engagement between the sliding sleeve and the slide rail; a damping element is connected to the end of the sliding sleeve near the longitudinal bridge keel, the damping element is connected to a connecting seat, and the connecting seat is connected to the longitudinal bridge keel. This invention ensures the stability of the longitudinal bridge keel and also improves the safety, stability, and forming quality of the cast-in-place crossbeam.

Description

Technical Field

[0001] This invention belongs to the field of building construction technology, specifically relating to an adjustable steel support device for the portal opening of a cast-in-place box girder. Background Technology

[0002] With the rapid development of municipal transportation, more and more elevated bridges are appearing, and it is common for elevated bridges to pass under existing roads and rivers. When cast-in-place box girders pass under structures, roads, or rivers, portal support devices need to be erected below the cast-in-place box girder. These portal support devices must not only meet the construction requirements of the cast-in-place box girder but also avoid impacting the existing roads, rivers, and structures below. Existing portal support devices include support columns, support joists (including crossbeams and longitudinal beams) set at the top of the support columns, flange trusses set on the support joists, and the casting formwork for the cast-in-place box girder. However, since the box girder is constructed in-place, during construction, in order to ensure the stability of the flange truss and prevent uneven stress on the flange truss from causing local bending of the formwork above it, which would affect the forming quality of the cast-in-place box girder, it is necessary to locally adjust the position of the support joists below the flange truss. However, this results in the support joists being designed as non-fixed, leading to poor stability. In addition, since the supporting keel under the flange truss is located in the edge area, its unfixed state poses certain safety hazards. Summary of the Invention

[0003] To address the problems in the prior art, this application proposes an adjustable steel support device for the portal opening of a cast-in-place box girder. By installing an adjustable keel anti-lateral component on the longitudinal bridge keel side of the supporting keel, the longitudinal bridge keel can be fixed and its position can be easily adjusted, thereby improving the safety and stability of the supporting keel and ensuring the forming quality of the cast-in-place box girder.

[0004] This invention proposes an adjustable steel support device for a portal opening of a cast-in-place box girder, comprising a supporting steel column, a supporting keel disposed on top of the supporting steel column, a flange truss disposed on the upper end of the supporting keel, and a cast-in-place box girder located on the upper end of the supporting keel and the flange truss; the supporting keel includes a main keel disposed on top of the supporting steel column, a longitudinal bridge keel disposed on the upper end of the main keel, and a transverse bridge keel disposed on the upper end of the longitudinal bridge keel; the upper end of the transverse bridge keel is connected to the flange truss; an adjustable keel anti-side component is disposed on the upper end of the main keel and on one side of the longitudinal bridge keel. The adjustable keel anti-side assembly includes: a slide rail, a clamp, a sliding sleeve, a locking element, a damping element, and a connecting seat; the slide rail is fixed to the upper end of the main keel by the clamp, and one end of the slide rail maintains a distance from the longitudinal bridge keel; the sliding sleeve is fitted onto the upper end of the slide rail, and the slide rail is movable along the length direction of the main keel; the locking element connects the sliding sleeve and the slide rail to restrict the movable engagement of the sliding sleeve and the slide rail; the end of the sliding sleeve near the longitudinal bridge keel is connected to the damping element, the damping element is connected to the connecting seat, and the connecting seat is connected to the longitudinal bridge keel.

[0005] Furthermore, the connecting seat includes a base plate, side panels, partitions, fixing nuts, and a third connecting bolt; the base plate is fixedly connected to the longitudinal bridge keel, and the side panels are connected to one end of the base plate opposite to the longitudinal bridge keel; the partitions are disposed within the space enclosed by the side panels to divide the space into several sub-cavities; the fixing nuts are located within the sub-cavities and are fixedly connected to the base plate; the third connecting bolt passes through the damping member and is connected to the fixing nuts.

[0006] By setting a fixing nut in the sub-cavity of the connecting seat, the connecting seat and the damping component are connected by the cooperation of the third connecting bolt and the fixing nut, which facilitates the disassembly and installation of the damping component on the connecting seat; at the same time, the partition is set on the base plate, and the base plate is fixedly connected to the longitudinal bridge keel, which improves the rigidity of the longitudinal bridge keel, ensures the connection effect between the longitudinal bridge keel and the adjustable keel anti-lateral component, and avoids the longitudinal bridge keel torsion and deformation.

[0007] Furthermore, the damping component includes a first connecting plate, a second connecting plate, and a plurality of damping columns disposed between the first connecting plate and the second connecting plate; the first connecting plate is connected to the third connecting bolt, and the second connecting plate is fixedly connected to the sliding sleeve.

[0008] Furthermore, the damping component also includes a first connecting bolt and a second connecting bolt; the damping column includes a rubber column and steel columns fixedly connected to both ends of the rubber column; one of the steel columns has a first threaded hole at its end that is connected to the first connecting bolt, and the first connecting bolt is also connected to the first connecting plate; the other steel column has a second threaded hole at its end that is connected to the second connecting bolt, and the second connecting bolt is also connected to the second connecting plate.

[0009] The damping columns are detachably connected via the first and second connecting bolts, allowing the number of damping columns to be increased or decreased according to actual needs. Steel columns are installed at both ends of the rubber columns, connecting to the first and second connecting plates respectively. This ensures a rigid connection between the damping components, the connecting seat, and the sliding sleeve. Simultaneously, the deformable energy-absorbing characteristics of the rubber columns allow the connecting seat and the sliding sleeve to maintain a certain deformation, thus absorbing energy and reducing vibration. This reduces the impact of ground vibration on the longitudinal bridge joists, ensuring the stability and safety of the support device.

[0010] Furthermore, the rubber column has recesses at both ends, and the steel column has a protrusion at one end. The protrusion is inserted into the recess and is interference-fitted with it.

[0011] Furthermore, a track plate is provided at the lower end of the slide rail, and the lower end of the track plate is in frictional engagement with the main keel. The clamp is clamped and fixed with the track plate and the main keel.

[0012] The frictional engagement between the track plate and the main keel enhances the stability of the connection between the slide rail and the main keel, preventing displacement of the slide rail. The track plate is held in place by clamps, facilitating adjustment of the clamps' position without obstructing the movement of the sliding sleeve.

[0013] Furthermore, there are multiple clamps, which are spaced apart along the length of the track plate.

[0014] Furthermore, the side wall of the slide rail is provided with horizontal scale lines, and the side wall of the sliding sleeve is provided with a pointer pointing to the scale lines.

[0015] The combination of pointers and scales makes it easy to intuitively understand the relative displacement between the sliding sleeve and the slide rail, which facilitates the adjustment of the longitudinal bridge keel displacement and improves the adjustment accuracy.

[0016] Furthermore, the locking element includes a positioning hole on the sliding sleeve, multiple pin holes on the slide rail, and a pin that passes through the positioning hole and any one of the pin holes; the multiple pin holes are spaced apart along the length of the slide rail.

[0017] Furthermore, a handle is provided at the upper end of the sliding sleeve.

[0018] The beneficial effects of this invention are as follows: By installing an adjustable keel anti-lateral component on one side of the longitudinal bridge keel and at the upper end of the main keel, the displacement of the longitudinal bridge keel is controlled by the displacement of its sliding sleeve. Simultaneously, it fixes and limits the longitudinal bridge keel, ensuring its stability, thereby improving the safety and stability of the supporting keel and the forming quality of the cast-in-place box girder. Furthermore, by connecting a damping element between the connecting seat and the sliding sleeve, the energy absorption and vibration reduction characteristics of the damping element can reduce the impact of ground vibration on the longitudinal bridge keel, further ensuring the stability and safety of the support device. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the transverse cross-sectional structure of the adjustable steel support device for the portal opening of a cast-in-place box girder according to the present invention.

[0020] Figure 2 This is a partial three-dimensional structural diagram of the adjustable steel support device for the portal opening of a cast-in-place box girder of the present invention, in which an adjustable keel anti-lateral component is installed on the support keel.

[0021] Figure 3 for Figure 2 A three-dimensional structural diagram of the adjustable keel anti-side component with the sliding sleeve and slide rail separated.

[0022] Figure 4 for Figure 3 Enlarged three-dimensional structural diagram of the connecting seat and damping component.

[0023] Figure 5 for Figure 4 A schematic diagram showing the structure where the connecting seat and damping component are separated.

[0024] Figure 6 for Figure 5 An exploded structural diagram of the connecting seat and damping component.

[0025] Figure 7 for Figure 6 A cross-sectional view of a damping column.

[0026] In the diagram, 1-supporting steel column; 2-supporting keel; 21-main keel; 22-longitudinal bridge keel; 23-transverse bridge keel; 3-flange truss; 4-cast-in-place box girder; 5-adjustable keel lateral resisting component; 51-slide rail; 511-track plate; 512-scale line; 52-clamp; 53-sliding sleeve; 531-handle; 532-pointer; 54-locking element; 541-positioning hole; 542-pin hole; 543-insert Pin; 55-Damping component; 551-First connecting plate; 552-Second connecting plate; 553-Damping column; 5531-Rubber column; 5532-Steel column; 554-First connecting bolt; 555-Second connecting bolt; 556-First threaded hole; 557-Second threaded hole; 56-Connecting seat; 561-Base plate; 562-Side plate; 563-Partition plate; 564-Fixing nut; 565-Third connecting bolt. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1 , Figure 2 The adjustable steel support device for the portal of the cast-in-place box girder shown includes a supporting steel column 1, a supporting keel 2 set on top of the supporting steel column 1, a flange plate truss 3 set on the upper end of the supporting keel 2, and a cast-in-place box girder 4 located on the upper end of the supporting keel 2 and the flange plate truss 3; the supporting keel 2 includes a main keel 21 set on top of the supporting steel column 1, a longitudinal bridge keel 22 set on the upper end of the main keel 21, and a transverse bridge keel 23 set on the upper end of the longitudinal bridge keel 22; the upper end of the transverse bridge keel 23 is connected to the flange plate truss 3; an adjustable keel anti-side component 5 is set on the upper end of the main keel 21 and on one side of the longitudinal bridge keel 22.

[0029] When the cast-in-place box girder 4 passes under an existing road or river, the transverse direction of the bridge is the length of the road or river. Two sets of supporting steel columns 1 are installed on both sides of the road and river, each set consisting of multiple supporting steel columns 1 spaced apart along the transverse direction of the bridge. Figure 1 The set of supporting steel columns 1 shown includes five supporting steel columns 1 and diagonal bracing members disposed between the five supporting steel columns 1.

[0030] like Figure 1As shown, the transverse direction is the width direction of the cast-in-place box girder 4, which is also the length direction of the main joists 21. The longitudinal direction is the length direction of the cast-in-place box girder 4, which is also the width direction of the main joists 21. Five supporting steel columns 1 in each group of supporting steel columns 1 are spaced apart along the transverse direction, and a horizontal main joist 21 is installed at the top of each group of supporting steel columns 1. Similarly, another horizontal main joist 21 is installed at the top of another group of supporting steel columns 1. Multiple longitudinal joists 22 are horizontally installed above these two main joists 21, spaced apart along the length direction of the main joists 21, with each longitudinal joist 22's length direction aligned with the length direction of the cast-in-place box girder 4. A transverse joist 23 is installed above the longitudinal joist 22, and the flange truss 3 is mounted on the transverse joist 23.

[0031] In some embodiments, an adjustable keel anti-side component 5 can be provided on one side of each longitudinal bridge keel 22. However, considering the number of longitudinal bridge keels 22, in this embodiment, it is preferable to provide adjustable keel anti-side components 5 on one side of several longitudinal bridge keels 22 below the flange truss 3. The position of the longitudinal bridge keel 22 on the main keel 21 is adjusted by using the adjustable keel anti-side components 5, so that it is translated a certain distance along the length direction of the main keel 21. This achieves the adjustment of the position and spacing of several longitudinal bridge keels 22 above the main keel 21, thereby ensuring the balanced stress on the flange truss 3 above it and the formwork above the flange truss 3, thus ensuring the forming quality of the cast-in-place box girder 4.

[0032] like Figure 2 , Figure 3 As shown, the adjustable keel anti-side assembly 5 includes: a slide rail 51, a clamp 52, a sliding sleeve 53, a locking member 54, a damping member 55, and a connecting seat 56; the slide rail 51 is fixed to the upper end of the main keel 21 by the clamp 52, and one end of the slide rail 51 maintains a distance from the longitudinal bridge keel 22; the sliding sleeve 53 is fitted onto the upper end of the slide rail 51, and the slide rail 51 moves along the length direction of the main keel 21; the locking member 54 connects the sliding sleeve 53 and the slide rail 51 to restrict the movement of the sliding sleeve 53 and the slide rail 51; the end of the sliding sleeve 53 near the longitudinal bridge keel 22 is connected to the damping member 55, the damping member 55 is connected to the connecting seat 56, and the connecting seat 56 is connected to the longitudinal bridge keel 22.

[0033] A track plate 511 is provided at the lower end of the slide rail 51. The lower end of the track plate 511 is in frictional engagement with the main keel 21. The clamp 52 clamps and fixes the track plate 511 and the main keel 21. The width of the track plate 511 is greater than the width of the slide rail 51, and the length of the track plate 511 is greater than the length of the slide rail 51, so that the clamp 52 can clamp the track plate 511. At the same time, compared with the slide rail 51 directly contacting the main keel 21, the contact between the track plate 511 and the main keel 21 can increase the friction area and prevent the slide rail 51 from shifting.

[0034] Multiple clamps 52 are spaced apart along the length of the track plate 511 to further enhance the fixing effect of the clamps 52 on the track plate 511. The clamps 52 can be commonly used vises. The main keel 21 includes a web plate, an upper flange plate, and a lower flange plate. The clamps 52 have two clamps located at opposite ends of the upper flange plate and the track plate 511, respectively, thereby clamping and fixing the track plate 511 to the upper flange plate. Because the clamps 52 are flexible and detachable, it also facilitates the adjustment of the position of the slide rail 51 on the main keel 21.

[0035] The slide rail 51 has a horizontal scale line 512 on its side wall, and the slide sleeve 53 has a pointer 532 pointing to the scale line 512 on its side wall. By comparing the scale line 512 corresponding to the pointer 532 before and after the slide sleeve 53 moves on the slide rail 51, the length of the slide sleeve 53's translation can be determined, so as to intuitively determine the position of the longitudinal bridge keel 22 on the main keel 21, thereby improving the control accuracy of the longitudinal bridge keel 22's translation.

[0036] To facilitate the movement of the sliding sleeve 53, a handle 531 is provided at the upper end of the sliding sleeve 53. In some embodiments, a winch can be provided at the end of the sliding sleeve 53 facing away from the connecting seat 56, with a steel wire rope wound on the winch. The other end of the steel wire rope is connected to the main keel 21 via a hook. Of course, a hanging rod or bolt can be installed on the main keel 21. By rotating the winch, the taut steel wire rope is wound up, thereby realizing the translation of the sliding sleeve 53.

[0037] The locking element 54 includes a positioning hole 541 on the sliding sleeve 53, multiple pin holes 542 on the slide rail 51, and a pin 543 that passes through the positioning hole 541 and any one of the pin holes 542; the multiple pin holes 542 are spaced apart along the length of the slide rail 51. When the pin 543 is inserted into the positioning hole 541 and the pin hole 542, the relative displacement between the sliding sleeve 53 and the slide rail 51 is restricted, and the sliding sleeve 53 cannot move.

[0038] Of course, in this embodiment, the sliding sleeve 53 and the slide rail 51 are in a friction fit. Even without using the locking element 54 to lock and fix the sliding sleeve 53 and the slide rail 51, the sliding sleeve 53 is still difficult to move. In this embodiment, the sliding sleeve 53 is made of U-shaped channel steel, and the slide rail 51 is made of square steel. The opening of the U-shaped channel steel faces downward and covers the upper end and both sides of the square steel, so that it can move along the length of the square steel.

[0039] like Figure 4 , Figure 5As shown, the connecting seat 56 includes a base plate 561, a side plate 562, a partition plate 563, a fixing nut 564, and a third connecting bolt 565. The base plate 561 is fixedly connected to the longitudinal bridge keel 22. The side plate 562 is connected to one end of the base plate 561 that is opposite to the longitudinal bridge keel 22. The partition plate 563 is arranged in the space enclosed by the side plate 562 to divide the space into several sub-cavities. The fixing nut 564 is located in the sub-cavities and is fixedly connected to the base plate 561. The third connecting bolt 565 passes through the damping member 55 and is connected to the fixing nut 564.

[0040] In this embodiment, there are multiple partitions 563, which are arranged vertically and horizontally. The partitions 563 can be regarded as reinforcing ribs of the base plate 561, which can improve the strength of the base plate 561. The base plate 561 is welded and fixed to the longitudinal bridge keel 22, thereby improving the structural strength and rigidity of the longitudinal bridge keel 22.

[0041] like Figure 6 , Figure 7 As shown, the damping element 55 includes a first connecting plate 551, a second connecting plate 552, and a plurality of damping posts 553 disposed between the first connecting plate 551 and the second connecting plate 552. The first connecting plate 551 is connected to a third connecting bolt 565, and the second connecting plate 552 is fixedly connected to a sliding sleeve 53. The first connecting plate 551 also serves to seal the sub-cavity of the connecting seat 56. The third connecting bolt 565 is threaded to the first connecting plate 551 and then connected to a fixing nut 564 in the sub-cavity, thereby connecting the first connecting plate 551 to the connecting seat 56. The first connecting plate 551 and the second connecting plate 552 are connected through the damping posts 553, thus realizing the connection between the damping element 55 and the connecting seat 56.

[0042] The damping component 55 also includes a first connecting bolt 554 and a second connecting bolt 555; the damping column 553 includes a rubber column 5531 and steel columns 5532 fixedly connected to both ends of the rubber column 5531; one of the steel columns 5532 has a first threaded hole 556 at its end that is connected to the first connecting bolt 554, and the first connecting bolt 554 is also connected to the first connecting plate 551; the other steel column 5532 has a second threaded hole 557 at its end that is connected to the second connecting bolt 555, and the second connecting bolt 555 is also connected to the second connecting plate 552.

[0043] When installing the damping component 55, first connect the first connecting plate 551 to one end of the damping column 553 using the first connecting bolt 554, then install the first connecting plate 551 on the connecting seat 56 using the third connecting bolt 565, then connect the second connecting plate 552 to the other end of the damping column 553 using the second connecting bolt 555, and finally weld the end of the second connecting plate 552 to the end of the sliding sleeve 53. In some embodiments, to facilitate the disassembly and reuse of the damping component 55 and the sliding sleeve 53, the connection between the second connecting plate 552 and the sliding sleeve 53 can be made by screw connection. After the cast-in-place box girder 4 is completed, the screws connecting the sliding sleeve 53 and the second connecting plate 552 can be removed to separate the sliding sleeve 53 from the second connecting plate 552, and then the second connecting plate 552, the damping column 553, and the first connecting plate 551 can be removed in sequence, thereby realizing the reuse of the damping component 55. The connecting seat 56 can be permanently fixed to one side of the longitudinal bridge keel 22 and used in rotation with the longitudinal bridge keel 22.

[0044] like Figure 7 As shown, the rubber column 5531 has recesses at both ends, and the steel column 5532 has a protrusion at one end. The protrusion is inserted into the recess and is interference-fitted with it. The protrusion and recesses limit the radial deformation of the rubber column 5531, preventing the steel column 5532 from separating from the rubber column 5531.

[0045] An adjustable keel anti-lateral component 5 is installed on one side of the longitudinal bridge keel 22 and above the main keel 21. The displacement of the longitudinal bridge keel 22 is controlled by the displacement of its sliding sleeve 53. At the same time, it fixes and limits the longitudinal bridge keel 22, ensuring its stability. This also improves the safety and stability of the supporting keel 2 and the forming quality of the cast-in-place box girder. In addition, by connecting a damping element 55 between the connecting seat 56 and the sliding sleeve 53, the energy absorption and vibration reduction characteristics of the damping element 55 can reduce the impact of ground vibration on the longitudinal bridge keel 22, further ensuring the stability and safety of the support device.

[0046] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. An adjustable steel support device for a portal opening of a cast-in-place box girder, comprising a supporting steel column, a supporting keel disposed on top of the supporting steel column, a flange plate truss disposed at the upper end of the supporting keel, and a cast-in-place box girder located at the upper end of the supporting keel and the flange plate truss; characterized in that, The supporting keel includes a main keel located at the top of the supporting steel column, a longitudinal bridge keel located at the upper end of the main keel, and a transverse bridge keel located at the upper end of the longitudinal bridge keel; the upper end of the transverse bridge keel is connected to the flange plate truss; an adjustable keel anti-side assembly is provided at the upper end of the main keel and on one side of the longitudinal bridge keel; the adjustable keel anti-side assembly includes: a slide rail, a clamp, a sliding sleeve, a locking element, a damping element, and a connecting seat; the slide rail is fixed to the upper end of the main keel by the clamp, and one end of the slide rail maintains a distance from the longitudinal bridge keel; the sliding sleeve is fitted onto the upper end of the slide rail, and the slide rail is movable along the length direction of the main keel; the locking element connects the sliding sleeve and the slide rail to restrict the movable engagement of the sliding sleeve and the slide rail; the end of the sliding sleeve near the longitudinal bridge keel is connected to the damping element, the damping element is connected to the connecting seat, and the connecting seat is connected to the longitudinal bridge keel.

2. The adjustable steel support device for the portal opening of a cast-in-place box girder according to claim 1, characterized in that, The connecting seat includes a base plate, side panels, partitions, fixing nuts, and a third connecting bolt; the base plate is fixedly connected to the longitudinal bridge keel, and the side panels are connected to one end of the base plate opposite to the longitudinal bridge keel; the partitions are disposed within the space enclosed by the side panels to divide the space into several sub-cavities; the fixing nuts are located in the sub-cavities and are fixedly connected to the base plate; the third connecting bolt passes through the damping member and is connected to the fixing nuts.

3. The adjustable steel support device for the portal opening of a cast-in-place box girder according to claim 2, characterized in that, The damping component includes a first connecting plate, a second connecting plate, and a plurality of damping columns disposed between the first connecting plate and the second connecting plate; the first connecting plate is connected to the third connecting bolt, and the second connecting plate is fixedly connected to the sliding sleeve.

4. The adjustable steel support device for the portal opening of a cast-in-place box girder according to claim 3, characterized in that, The damping component further includes a first connecting bolt and a second connecting bolt; the damping column includes a rubber column and steel columns fixedly connected to both ends of the rubber column; one of the steel columns has a first threaded hole at its end that is connected to the first connecting bolt, and the first connecting bolt is also connected to the first connecting plate; the other steel column has a second threaded hole at its end that is connected to the second connecting bolt, and the second connecting bolt is also connected to the second connecting plate.

5. The adjustable steel support device for the portal opening of a cast-in-place box girder according to claim 4, characterized in that, The rubber column has recesses at both ends, and the steel column has a protrusion at one end. The protrusion is inserted into the recess and is interference-fitted with it.

6. The adjustable steel support device for the portal opening of a cast-in-place box girder according to claim 1, characterized in that, The lower end of the slide rail is provided with a track plate, the lower end of the track plate is in frictional engagement with the main keel, and the clamp is clamped and fixed with the track plate and the main keel.

7. The adjustable steel support device for the portal opening of a cast-in-place box girder according to claim 6, characterized in that, The clamps are multiple and spaced apart along the length of the track plate.

8. The adjustable steel support device for the portal opening of a cast-in-place box girder according to claim 1, characterized in that, The slide rail has horizontal scale lines on its side wall, and the slide sleeve has a pointer on its side wall that points to the scale lines.

9. The adjustable steel support device for the portal opening of a cast-in-place box girder according to claim 1, characterized in that, The locking element has a positioning hole on the sliding sleeve, multiple pin holes on the slide rail, and a pin that passes through the positioning hole and any one of the pin holes; the multiple pin holes are spaced apart along the length of the slide rail.

10. The adjustable steel support device for the portal opening of a cast-in-place box girder according to claim 1, characterized in that, A handle is provided at the upper end of the sliding sleeve.

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