Overhanging stair formwork system and construction method thereof

Abstract

This invention provides a cantilevered staircase formwork system and its construction method, solving the problem that the concrete surface bonding strength at the connection between the staircase and the cantilever slab after cantilevered staircase construction cannot achieve the same bonding strength as that obtained by integral casting, thus requiring further improvement. This invention includes multiple cantilevered staircase formwork units that can be spliced ​​together vertically. Each cantilevered staircase formwork unit includes a cantilever slab formwork and a staircase formwork inclined at the top of the cantilever slab formwork. Using this invention for cantilevered staircase construction not only avoids the hassle of repeatedly erecting and dismantling steel pipe scaffolding, but also allows for the integral casting of the staircase and cantilever slab across multiple floors, solving the problem of intermittent construction time in multi-story staircase construction. This not only saves construction time but also results in better bonding strength between the cast staircase and the cantilever slab.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to cantilever staircase formwork systems and their construction methods. Background Technology

[0002] In order to obtain more usable indoor space during the construction process, staircases are often cantilevered on the outside of the main building to reduce the shared area.

[0003] The current cantilever staircases have the following problems during construction: (1) When the cantilever staircase formwork is erected and dismantled on each floor, in order to reuse the materials, the support frame used to support the formwork needs to be re-installed and dismantled. These scaffolds are mostly made of many steel pipes, which are troublesome to dismantle and install; (2) When constructing the cantilever staircase, the bottom of the cantilever staircase is usually constructed first as a cantilever slab for support, and then the staircase is poured on the cantilever slab. Due to the interruption of the construction time, the concrete surface layer bonding strength at the connection between the staircase and the cantilever slab cannot achieve the bonding strength effect of the concrete surface layer that can be obtained by integral pouring, and still needs to be improved. Summary of the Invention

[0004] To address the issue in the prior art that the bonding strength of the concrete surface layer at the connection between the cantilever staircase and the cantilever slab cannot reach the bonding strength effect that can be obtained by integral casting of the concrete surface layer after the construction of the cantilever staircase, and that further improvement is still needed, this invention proposes a cantilever staircase formwork system and its construction method.

[0005] The technical solution of the present invention is: a cantilevered stair formwork system, comprising multiple cantilevered stair formwork units that can be spliced ​​together vertically, wherein the cantilevered stair formwork unit includes a cantilevered slab formwork and a stair formwork inclined at the top of the cantilevered slab formwork;

[0006] The cantilever slab template is a shell-like structure with an open left end and a hollow interior. The cantilever slab template includes a cantilever bottom template and a cantilever top template. The cantilever bottom template includes a first cantilever bottom plate. The front, right and rear sides of the first cantilever bottom plate are provided with a first cantilever side plate, a second cantilever side plate and a fourth cantilever side plate connected end to end. The cantilever top template is detachably fixed on the top of the first cantilever side plate, the second cantilever side plate and the fourth cantilever side plate.

[0007] The first cantilevered base plate has a first channel slot that is open from top to bottom. An isolation frame plate is provided around the first channel slot on the first cantilevered base plate. The top of the isolation frame plate abuts against the bottom of the cantilevered top template. The cantilevered top template has a second channel slot that is open from top to bottom. The second channel slot corresponds to the first channel slot vertically. Both the second channel slot and the first channel slot correspond to the stair template vertically.

[0008] The stair formwork includes a bottom formwork and a top formwork that are inclined from left to right and from bottom to top. The top formwork is a grooved plate structure with an opening at the bottom. The top formwork includes a step top plate, which is a step-shaped plate structure. A baffle plate structure is fixedly installed on the lower part of the periphery of the step top plate.

[0009] The first step at the left end of the staircase top formwork is detachably fixed on the cantilever top formwork. The cantilever top formwork has a first connecting slot that is open from top to bottom, and the first connecting slot corresponds to the lower opening of the first step.

[0010] The cantilevered top formwork is equipped with a support rod system to support the bottom formwork of the stairs. The bottom formwork of the stairs and the top formwork of the stairs are detachably and fixedly connected. The bottom formwork of the stairs rests against the bottom of the enclosure structure. The bottom formwork of the stairs is used to close the lower opening area of ​​the top formwork of the stairs, except for the area corresponding to the first step.

[0011] The top of the last step on the right side of the stepped top plate is provided with a second connecting slot that is open from top to bottom. The top of the last step on the right side of the stepped top plate is detachably and fixedly connected to the bottom of the first cantilevered base plate on the upper layer. The first cantilevered base plate is provided with a third connecting slot that is open from top to bottom, and the third connecting slot corresponds to the second connecting slot vertically.

[0012] Preferably, the first, second, and fourth cantilever side plates are all provided with rebar slots for the longitudinally and transversely arranged cantilever slab rebars to pass through.

[0013] Preferably, the bottom of the rebar slot is an open structure.

[0014] Preferably, a removable rebar connector is inserted into the rebar slot. The rebar connector is a plate-shaped structure with a rebar insertion hole for the rebar to pass through. Wing plates are fixed on the left and right sides of the rebar connector, and the wing plates have a second through hole that is open from front to back.

[0015] The first, second, and fourth cantilever side plates are all provided with fixing grooves corresponding to the front and rear of the wing plates. The fixing grooves are front-opening structures and are connected to the rebar slots.

[0016] The wing plate is inserted into the fixing groove, and a screw for fixing the wing plate into the fixing groove is inserted into the second through hole.

[0017] Preferably, the left end of the bottom formwork of the staircase is hinged to the top formwork of the cantilevered roof, so that the bottom formwork of the staircase can swing up and down.

[0018] The support rod system includes vertical hydraulic support rods spaced apart on the top of the cantilevered top formwork, with the top of the hydraulic support rods abutting against the bottom of the stair bottom formwork.

[0019] Preferably, the top of the hydraulic support rod is provided with a top block, the top surface of which is an inclined surface that slopes from left to right and from bottom to top, and the top surface of the top block is used to abut against the bottom surface of the bottom formwork of the staircase.

[0020] Preferably, the first step has multiple first vibration holes spaced apart front to back and open from top to bottom, which are used to install vibrating rods.

[0021] Preferably, multiple evenly distributed second vibration holes are provided on the cantilever top formwork. The second vibration holes have a vertically open structure, and the lower end of the second vibration hole is connected to the hollow space inside the cantilever bottom formwork.

[0022] The construction method of the cantilever staircase formwork system includes the following steps: S1~ Install hydraulic support rods in an array on the ground to build a bottom telescopic support frame;

[0023] S2~ The cantilevered bottom formwork is hoisted onto the top of the bottom telescopic support frame, and a steel plate is installed in the third connecting slot of the cantilevered bottom formwork of this layer for filling and sealing. The steel plate abuts against the telescopic support frame to reach the top.

[0024] S3~ Controls the hydraulic support rods of the bottom telescopic support frame to slowly lift the cantilever bottom formwork until the steel bars extending from the building floor slab are inserted into the cavity formed by the cantilever bottom formwork;

[0025] S4~Build a steel reinforcement mesh for the cantilever slab inside the cavity of the cantilever bottom formwork. The longitudinal and transverse bars of the steel reinforcement mesh for the cantilever slab are all passed through the first through hole of the steel connector, and the steel reinforcement mesh for the cantilever slab is fixedly connected to the steel bars extending from the building floor slab.

[0026] S5~ Hoist the cantilevered top formwork to the top of the cantilevered bottom formwork, and fix the cantilevered top formwork and the cantilevered bottom formwork with bolts;

[0027] S6~ Install the stair steel mesh on the bottom formwork of the staircase, hoist the top formwork of the staircase onto the cantilevered top formwork, fix the first step of the top formwork of the staircase to the cantilevered top formwork with bolts, control the hydraulic support rod to lift the bottom formwork of the staircase upwards so that the bottom formwork of the staircase closes the lower opening area of ​​the top formwork of the staircase except for the area corresponding to the first step, and the top formwork of the staircase closes the stair steel mesh in the cavity.

[0028] S7~ Install a vibrating rod in the first and second vibration holes, and seal the gap between the vibrating rod and the first or second vibration hole with an annular rubber gasket.

[0029] S8~ Hoist the upper cantilever bottom formwork to the upper building floor slab, and insert the steel bars extending from the building floor slab into the cavity formed by the cantilever bottom formwork. Detachably and fix the top of the last step on the right end of the stair top slab to the bottom of the first cantilever bottom slab of the upper layer, so that the third connecting slot corresponds to the second connecting slot and is connected. Repeat steps S4~S7 to complete the installation of the upper cantilever stair formwork unit.

[0030] S9~ Repeat step S8 to install the upper cantilever stair formwork units sequentially from bottom to top until all cantilever stair formwork units are installed.

[0031] S10~ Inject concrete grout into the second connecting slot of the uppermost cantilevered stair formwork unit, and simultaneously start all the vibrators. The concrete grout flows from top to bottom under the push of gravitational potential energy and the vibration of the vibrators, gradually filling all the cantilevered stair formwork units.

[0032] After the concrete of S11~with the cantilevered staircase has solidified, the staircase formwork units shall be removed step by step from top to bottom in the order of removal of the top formwork of the staircase, the top formwork of the cantilevered staircase, the steel reinforcement connectors, and the bottom formwork of the cantilevered staircase.

[0033] Advantages of this invention: When using this invention for cantilever staircase construction, it not only avoids the trouble of repeatedly building and dismantling steel pipe scaffolding, but also allows the stairs and cantilever slabs of multiple floors to be cast as a single unit during pouring. This solves the problem of interrupted construction time in the pouring of stairs in multi-story buildings, saving construction time, making the construction speed faster, and resulting in better bonding strength between the finished stairs and cantilever slabs. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the connection structure between the cantilevered staircase formwork unit and the main building of two adjacent floors in Example 1.

[0036] Figure 2 for Figure 1 A structural schematic diagram of the cantilevered staircase formwork unit;

[0037] Figure 3 for Figure 2A schematic diagram of the internal structure of the cantilevered bottom formwork;

[0038] Figure 4 for Figure 3 A structural schematic diagram of the steel reinforcement connectors in the diagram;

[0039] Figure 5 for Figure 2 A structural schematic diagram of the cantilevered top formwork and the bottom formwork of the stairs above it;

[0040] Figure 6 for Figure 2 A structural diagram of the staircase top formwork;

[0041] Figure 7 for Figure 2 A schematic diagram of the hydraulic support rod and its top block;

[0042] In the diagram, 1. Building exterior wall, 2. Building floor slab, 3. Cantilever bottom formwork, 301. First cantilever bottom slab, 302. First cantilever side slab, 303. Second cantilever side slab, 304. Third cantilever side slab, 305. First passageway slot, 4. Isolation frame plate, 5. Third connecting slot, 6. Rebar connector, 601. First through hole, 7. Wing plate, 701. Second through hole, 8. First connecting plate, 9. Cantilever top formwork, 10. Second passageway slot, 11. Second connecting plate, 12. Hydraulic support rod, 13. Staircase bottom formwork, 14. First connecting slot, 15. Fixing plate, 16. Staircase top formwork, 1601. Step top slab, 1602. Second connecting slot, 1603. First step, 1604. Third connecting plate, 17. Top block, 18. First vibrating hole, 19. Second vibrating hole. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Example 1: Cantilevered staircase formwork system, such as Figure 1 As shown, it includes multiple cantilevered stair formwork units that can be spliced ​​together vertically. Each cantilevered stair formwork unit includes a cantilever slab formwork and a stair formwork inclined on top of the cantilever slab formwork.

[0045] like Figure 2 As shown, the cantilever slab template is a shell-like structure with an opening at the left end and a hollow interior. The cantilever slab template includes a bottom cantilever template 3 and a top cantilever template 9.

[0046] like Figure 3 As shown, the cantilever bottom template 3 includes a first cantilever bottom plate 301. The front, right and rear sides of the first cantilever bottom plate 301 are provided with a first cantilever side plate 302, a second cantilever side plate 303 and a fourth cantilever side plate 304 connected end to end. The cantilever top template 9 is detachably fixed on the top of the first cantilever side plate 302, the second cantilever side plate 303 and the fourth cantilever side plate 304.

[0047] The first cantilevered base plate 301 is provided with a first channel slot 305 that is open at both the top and bottom. A partition frame plate 4 is provided around the first channel slot 305 on the first cantilevered base plate 301. The top of the partition frame plate 4 abuts against the bottom of the cantilevered top template 9. The cantilevered top template 9 is provided with a second channel slot 10 that is open at both the top and bottom. The second channel slot 10 corresponds vertically to the first channel slot 305. Both the second channel slot 10 and the first channel slot 305 correspond vertically to the stair template.

[0048] The function of the second channel slot 10, the isolation frame plate 4, and the first channel slot 305 is to automatically form a passage for people to pass through the stairs between the upper and lower floors after pouring.

[0049] To facilitate the construction of the steel reinforcement mesh for cantilever slabs, such as Figure 2 and Figure 3 As shown, the first cantilever side plate 302, the second cantilever side plate 303 and the fourth cantilever side plate 304 are all provided with steel bar slots for the longitudinal and transverse cantilever slab steel bars to pass through, and the bottom of the steel bar slots is an open structure.

[0050] A removable rebar connector 6 is inserted into the rebar slot. The rebar connector 6 is a plate-shaped structure with rebar insertion holes for the rebar to pass through. Wing plates 7 are fixed on the left and right sides of the rebar connector 6. The wing plates 7 have a second through hole 701 that is open at the front and back.

[0051] The first cantilever side plate 302, the second cantilever side plate 303 and the fourth cantilever side plate 304 are all provided with fixing grooves corresponding to the front and rear of the wing plate 7. The fixing grooves are front-opening structures and are connected to the steel bar slots.

[0052] The wing plate 7 is inserted into the fixing groove, and a screw for fixing the wing plate 7 into the fixing groove is inserted into the second through hole 701.

[0053] like Figure 2 As shown, the stair formwork includes a bottom formwork 13 and a top formwork 16 that are inclined from left to right and from bottom to top.

[0054] like Figure 6As shown, the stair top template 16 is a grooved plate structure with an opening at the bottom. The stair top template 16 includes a step top plate 1601, which is a step-shaped plate structure. A baffle plate structure is fixedly provided on the lower periphery of the step top plate 1601.

[0055] The first step 1603 at the left end of the stair top formwork 16 is detachably fixed on the cantilever top formwork 9. The cantilever top formwork 9 has a first connecting slot 14 that is open from top to bottom, and the first connecting slot 14 corresponds to the lower opening of the first step 1603.

[0056] like Figure 5 As shown, the left end of the bottom formwork 13 of the staircase is hinged to the cantilever top formwork 9 so that the bottom formwork 13 of the staircase can swing up and down, preventing the bottom formwork 13 of the staircase from shifting during use.

[0057] The cantilevered top formwork 9 is provided with a support rod system for supporting the bottom formwork 13 of the stairs. The support rod system includes hydraulic support rods 12 that are vertically spaced on the top of the cantilevered top formwork 9 and spaced on the left and right. The top of the hydraulic support rods 12 abuts against the bottom of the bottom formwork 13 of the stairs.

[0058] To increase the effective support area of ​​the top of the hydraulic support rod 12 on the bottom formwork of the staircase, such as Figure 7 As shown, the top of the hydraulic support rod 12 is provided with a top block 17. The top surface of the top block 17 is an inclined surface that slopes from left to right and from bottom to top. The top surface of the top block 17 is used to abut against the bottom surface of the stair bottom template 13.

[0059] The bottom formwork 13 and the top formwork 16 of the stairs are detachably and fixedly connected. The bottom formwork 13 of the stairs abuts against the bottom of the enclosure structure. The bottom formwork 13 of the stairs is used to close the lower opening area of ​​the top formwork 16 of the stairs, except for the area corresponding to the first step 1603.

[0060] The top of the last step on the right side of the stepped top plate 1601 is provided with a second connecting slot 1602 that is open from top to bottom. The top of the last step on the right side of the stepped top plate 1601 is detachably and fixedly connected to the bottom of the first cantilevered base plate 301 on the upper layer. The first cantilevered base plate 301 is provided with a third connecting slot 5 that is open from top to bottom. The third connecting slot 5 corresponds to the second connecting slot 1602 vertically.

[0061] To facilitate the flow of concrete grout between cantilevered staircase formwork units, such as Figure 1 , Figure 2As shown, the first step 1603 has multiple first vibration holes 18 spaced apart and open vertically, and the cantilevered top template 9 has multiple evenly distributed second vibration holes 19. The second vibration holes 19 are open vertically, and their lower ends are connected to the hollow space inside the cantilevered bottom template 3. Both the first vibration holes 18 and the second vibration holes 19 are used to install vibrating rods.

[0062] The construction method of the cantilever staircase formwork system includes the following steps: S1~ Install hydraulic support rods in an array on the ground to build a bottom telescopic support frame;

[0063] S2~ The cantilevered bottom formwork 3 is hoisted onto the top of the bottom telescopic support frame, and a steel plate is installed in the third connecting slot 5 of the cantilevered bottom formwork 3 of this layer for filling and sealing. The steel plate abuts against the telescopic support frame to reach the top.

[0064] S3~ Controls the hydraulic support rod of the bottom telescopic support frame to slowly lift the cantilever bottom formwork 3 until the steel bar extending from the building floor slab 2 is inserted into the cavity formed by the cantilever bottom formwork 3;

[0065] S4~Build a steel reinforcement mesh for the cantilever slab inside the cavity of the cantilever bottom formwork 3. The longitudinal and transverse bars of the steel reinforcement mesh of the cantilever slab are all passed through the first through hole 601 of the steel connector 6 to fix the steel reinforcement mesh of the cantilever slab to the steel bars extending from the building floor slab 2.

[0066] S5~ Hoist the cantilevered top formwork 9 to the top of the cantilevered bottom formwork 3, and fix the cantilevered top formwork 9 and the cantilevered bottom formwork 3 with bolts;

[0067] S6~ Install the stair steel mesh on the bottom formwork 13 of the staircase, hoist the top formwork 16 of the staircase onto the cantilevered top formwork 9, fix the first step 1603 of the top formwork 16 of the staircase to the cantilevered top formwork 9 with bolts, control the hydraulic support rod 12 to lift the bottom formwork 13 of the staircase upward, so that the bottom formwork 13 of the staircase closes the lower opening area of ​​the top formwork 16 of the staircase except for the area corresponding to the first step 1603, and the top formwork 16 of the staircase closes the stair steel mesh in the cavity;

[0068] S7~ Install a vibrating rod in the first vibrating hole 18 and the second vibrating hole 19, and seal the gap between the vibrating rod and the first vibrating hole 18 or the second vibrating hole 19 with an annular rubber pad.

[0069] S8~ Hoist the upper cantilever bottom formwork 3 to the upper building floor slab 2, and insert the steel bars extending from the building floor slab 2 into the cavity formed by the cantilever bottom formwork 3. Detachably and fix the top of the last step on the right end of the stair top plate 1601 to the bottom of the upper first cantilever bottom plate 301, so that the third connecting slot 5 corresponds to and connects with the second connecting slot 1602. Repeat steps S4~S7 to complete the installation of the upper cantilever stair formwork unit.

[0070] S9~ Repeat step S8 to install the upper cantilever stair formwork units sequentially from bottom to top until all cantilever stair formwork units are installed.

[0071] S10~ Inject concrete grout into the second connecting slot 1602 of the uppermost cantilevered stair formwork unit, and at the same time start all the vibrators. The concrete grout flows from top to bottom under the push of gravitational potential energy and the vibration of the vibrators, gradually filling all the cantilevered stair formwork units.

[0072] After the concrete of S11~with the cantilevered staircase has solidified, the staircase formwork units are gradually removed from top to bottom in the order of removing the top formwork 16 of the staircase, the cantilevered top formwork 9, the steel reinforcement connector 6, and the cantilevered bottom formwork.

[0073] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims and not by the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A cantilevered staircase formwork system, characterized in that: It includes multiple cantilevered stair formwork units that can be spliced ​​together vertically. Each cantilevered stair formwork unit includes a cantilever slab formwork and a stair formwork inclined on top of the cantilever slab formwork. The cantilever slab template is a shell-like structure with an open left end and a hollow interior. The cantilever slab template includes a cantilever bottom template (3) and a cantilever top template (9). The cantilever bottom template (3) includes a first cantilever bottom plate (301). The front, right and rear sides of the first cantilever bottom plate (301) are provided with a first cantilever side plate (302), a second cantilever side plate (303) and a fourth cantilever side plate (304) connected end to end. The cantilever top template (9) is detachably fixed on the top of the first cantilever side plate (302), the second cantilever side plate (303) and the fourth cantilever side plate (304). The first cantilever base plate (301) is provided with a first channel slot (305) that is open to the top and bottom. The first cantilever base plate (301) is provided with an isolation frame plate (4) surrounding the first channel slot (305). The top of the isolation frame plate (4) abuts against the bottom of the cantilever top template (9). The cantilever top template (9) is provided with a second channel slot (10) that is open to the top and bottom. The second channel slot (10) corresponds to the first channel slot (305) vertically. Both the second channel slot (10) and the first channel slot (305) correspond to the stair template vertically. The stair formwork includes a bottom formwork (13) and a top formwork (16) that are inclined from left to right and from bottom to top. The top formwork (16) is a grooved plate structure with an opening at the bottom. The top formwork (16) includes a step top plate (1601), which is a step-shaped plate structure. A baffle plate structure is fixedly provided on the lower part of the periphery of the step top plate (1601). The first step (1603) at the left end of the stair top template (16) can be detachably fixed on the cantilever top template (9). The cantilever top template (9) has a first connecting slot (14) that is open from top to bottom. The first connecting slot (14) corresponds to the lower opening of the first step (1603). The cantilever top formwork (9) is provided with a support rod system for supporting the bottom formwork (13) of the stairs. The bottom formwork (13) of the stairs and the top formwork (16) of the stairs are detachably and fixedly connected. The bottom formwork (13) of the stairs rests against the bottom of the enclosure structure. The bottom formwork (13) of the stairs is used to close the lower opening area of ​​the top formwork (16) of the stairs except for the area corresponding to the first step (1603). The top of the last step at the right end of the stepped top plate (1601) is provided with a second connecting slot (1602) that is open from top to bottom. The top of the last step at the right end of the stepped top plate (1601) is detachably and fixedly connected to the bottom of the first cantilevered base plate (301) of the upper layer. The first cantilevered base plate (301) is provided with a third connecting slot (5) that is open from top to bottom. The third connecting slot (5) corresponds to the second connecting slot (1602) vertically. The first cantilever side plate (302), the second cantilever side plate (303) and the fourth cantilever side plate (304) are all provided with steel bar slots for the longitudinal and transverse cantilever slab steel bars to pass through. A removable rebar connector (6) is inserted into the rebar slot. The rebar connector (6) is a plate-shaped structure. The rebar connector (6) has a first through hole (601) for the rebar to pass through. Wing plates (7) are fixed on the left and right sides of the rebar connector (6). The wing plates (7) have a second through hole (701) that is open from front to back. The first cantilever side plate (302), the second cantilever side plate (303) and the fourth cantilever side plate (304) are all provided with fixing grooves corresponding to the front and rear of the wing plate (7). The fixing grooves are front-opening structures and are connected to the steel bar slots. The wing plate (7) is inserted into the fixing groove, and a screw for fixing the wing plate (7) into the fixing groove is inserted through the second through hole (701); The first step (1603) has multiple first vibration holes (18) that are spaced apart front and back and open from top to bottom. The first vibration holes (18) are used to install vibration rods. Multiple evenly distributed second vibration holes (19) are provided on the cantilever top template (9). The second vibration holes (19) are open from top to bottom, and the lower end of the second vibration holes (19) is connected to the hollow space inside the cantilever bottom template (3).

2. The cantilevered staircase formwork system as described in claim 1, characterized in that: The bottom of the rebar slot is open.

3. The cantilevered staircase formwork system as described in claim 1, characterized in that: The left end of the bottom formwork (13) of the stairs is hinged to the cantilever top formwork (9) so that the bottom formwork (13) of the stairs can swing up and down. The support rod system includes vertical hydraulic support rods (12) spaced apart on the top of the cantilever top formwork (9), with the top of the hydraulic support rods (12) abutting against the bottom of the stair bottom formwork (13).

4. The cantilevered staircase formwork system as described in claim 3, characterized in that: The top of the hydraulic support rod (12) is provided with a top block (17). The top surface of the top block (17) is an inclined surface that slopes from left to right and from bottom to top. The top surface of the top block (17) is used to abut against the bottom surface of the bottom template (13) of the stairs.

5. The construction method of the cantilever staircase formwork system as described in any one of claims 1-4, characterized in that, Includes the following steps: S1~ Hydraulic support rods are installed in an array on the ground to build a retractable support frame at the bottom; S2~ The cantilever bottom template (3) is hoisted to the top of the bottom telescopic support frame, and a steel plate is installed in the third connecting slot (5) of the cantilever bottom template (3) of this layer for filling and sealing. The steel plate abuts against the top of the telescopic support frame. S3~ controls the hydraulic support rod of the bottom telescopic support frame to slowly lift the cantilever bottom formwork (3) until the steel bar extending from the building floor slab (2) is inserted into the cavity formed by the cantilever bottom formwork (3); S4~Build a steel reinforcement mesh for the cantilever slab in the cavity of the cantilever bottom formwork (3). The longitudinal and transverse bars of the steel reinforcement mesh of the cantilever slab are all inserted into the first through hole (601) of the steel reinforcement connector (6) to fix the steel reinforcement mesh of the cantilever slab to the steel bars extending from the building floor slab (2). S5~ Hoist the cantilever top formwork (9) to the top of the cantilever bottom formwork (3), and fix the cantilever top formwork (9) and the cantilever bottom formwork (3) with bolts; S6~ Install the stair steel mesh on the bottom formwork (13), hoist the top formwork (16) onto the cantilever top formwork (9), fix the first step (1603) of the top formwork (16) to the cantilever top formwork (9) with bolts, control the hydraulic support rod (12) to lift the bottom formwork (13) upward, so that the bottom formwork (13) closes the lower opening area of ​​the top formwork (16) except for the area corresponding to the first step (1603), and the top formwork (16) closes the stair steel mesh in the cavity; S7~ Install a vibrating rod in the first vibrating hole (18) and the second vibrating hole (19), and seal the gap between the vibrating rod and the first vibrating hole (18) or the second vibrating hole (19) with an annular rubber pad; S8~ Hoist the upper cantilever bottom formwork (3) to the upper building floor slab (2), and insert the steel bars extending from the building floor slab (2) into the cavity formed by the cantilever bottom formwork (3). Detachably fix the top of the last step at the right end of the stair top plate (1601) to the bottom of the first cantilever bottom plate (301) of the upper layer, so that the third connecting slot (5) corresponds to and connects with the second connecting slot (1602) vertically. Repeat steps S4~S7 to complete the installation of the upper cantilever stair formwork unit. S9~ Repeat step S8 to install the upper cantilever stair formwork units sequentially from bottom to top until all cantilever stair formwork units are installed. S10~ Inject concrete grout into the second connecting slot (1602) of the uppermost cantilevered stair formwork unit, and simultaneously start all the vibrators. The concrete grout flows from top to bottom under the push of gravitational potential energy and the vibration of the vibrators, gradually filling all the cantilevered stair formwork units. S11~After the concrete of the cantilever staircase has solidified, the staircase formwork units are gradually removed from top to bottom in the order of removal of the top formwork (16) of the staircase, the cantilever top formwork (9), the steel reinforcement connectors (6), and the cantilever bottom formwork.

Images