A cast-in-situ concrete spiral stair formwork method and formwork system

Abstract

The application discloses a cast-in-situ concrete spiral stair formwork supporting method and a formwork system, and comprises the following steps: S1, taking a step front edge line as a reference line for spiral stair wire positioning, first positioning the positions of step front edge lines of each step of the spiral stair, and completing wire positioning of the step front edge lines; S2, secondly, positioning a bottom plate generatrix position of the spiral stair and supporting inner circumferential vertical poles, outer circumferential vertical poles and radial horizontal poles; S3, connecting stabilizing poles between the inner circumferential vertical poles and the outer circumferential vertical poles respectively; and S4, finally, laying stair formworks on the radial horizontal poles. Through the application, a precise, reliable, simple and easy wire positioning and formwork supporting method and a formwork system with simple and clear stress, safe and reliable structure are provided, and the construction quality of the cast-in-situ concrete spiral stair is improved, the construction difficulty is reduced, and the construction period is shortened.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building spiral stair construction, more particularly to a cast-in-place concrete spiral stair formwork supporting method and a formwork system. BACKGROUND

[0002] Compared with ordinary straight stairs, spiral stairs have the advantages of small floor area, beautiful appearance, light structure and flexible arrangement. Compared with steel and wood spiral stairs, cast-in-place concrete spiral stairs have the advantages of large bearing capacity, good integrity, comfortable use, corrosion resistance and good fire resistance, and are the first choice for spiral stairs in public buildings.

[0003] However, compared with ordinary straight stairs, cast-in-place concrete spiral stairs also have the disadvantages of large construction difficulty, complex construction process and difficult construction quality guarantee. In particular, the layout positioning and formwork processing and supporting of the spatial curved surface are involved, and the layout positioning and formwork supporting of the cast-in-place concrete spiral stairs are the most difficult part of the spiral stair construction and the key to guarantee the construction quality of the cast-in-place concrete spiral stairs.

[0004] Currently, there is no unified and standard construction method for the layout positioning and formwork supporting of cast-in-place concrete spiral stairs. Through literature search, most of the current related patents, such as: open cast-in-place concrete folded plate spiral stairs (application publication number: CN104947866 A), cast-in-place cantilever spiral stairs and construction method thereof (application publication number: CN110258987 A) and the like have poor referenceability and operability for the layout positioning and formwork supporting method of cast-in-place concrete spiral stairs.

[0005] Currently, cast-in-place concrete spiral stairs are mostly supported by formwork workers according to experience. The common formwork supporting method is to stand a steel pipe as a center stand in the center of the spiral stairs, stand a number of steel pipes as outer peripheral stands around the spiral stairs, and set horizontal steel pipes as radial rods between the center stand and the outer peripheral stands, so as to form a formwork support to support the spiral stair formwork. The connection and fixing mode of the spiral stair formwork and the formwork support is mostly iron wire binding. The disadvantages of this formwork supporting method are: 1) one end of all radial rods is supported on a center stand, causing the vertical load of the center stand to be too large. 2) Since the radial rods are fixed on the side of the center stand, the axis of the radial rods does not intersect with the center stand, so the radial rods do not pass through the center of the spiral stairs, and the radial rods do not coincide with the front edge line of the spiral stair steps, which leads to complex layout positioning, difficult formwork supporting and large error of the spiral stairs. 3) The formwork and the support are fixed by iron wire binding, which is prone to displacement and deformation of the formwork during construction, affecting the finished product quality of the spiral stairs.

[0006] In summary, there are some shortcomings in the construction of cast-in-place concrete spiral staircases, such as difficult line laying, large error, inaccurate template positioning and size, unstable template setting and easy deformation, which can easily cause engineering quality accidents and engineering safety accidents. SUMMARY

[0007] The present application aims to disclose a cast-in-place concrete spiral staircase formwork setting method and a formwork system, to provide an accurate, reliable, simple and easy line laying positioning and formwork setting method, and a formwork system with simple and clear stress, safe and reliable structure, so as to improve the construction quality of cast-in-place concrete spiral staircases, reduce the construction difficulty and shorten the construction period.

[0008] To achieve the above-mentioned purpose, the present application provides a cast-in-place concrete spiral staircase formwork setting method, comprising the following steps:

[0009] S1. Taking the step front edge line as the reference line for spiral staircase line laying positioning, first positioning the positions of the step front edge lines of the spiral staircase, and completing the line laying positioning of the step front edge lines;

[0010] S11. Determining the position of the center point of the spiral staircase on the ground of the starting floor, taking the center point of the spiral staircase as the center, and drawing the inner and outer circular arcs of the spiral staircase;

[0011] S12. According to the position of the starting step front edge line of the spiral staircase and the rotation angle of each step, drawing the horizontal projection lines of the step front edge lines on the ground of the starting floor;

[0012] S13. Drawing the horizontal projection lines of the step front edge lines of the spiral staircase upward to the height of the step to the floor, and the spatial position of the step front edge line can be obtained;

[0013] S2. Secondly, positioning the position of the bottom plate generatrix of the spiral staircase and setting the inner and outer circumferential vertical poles and the radial horizontal poles;

[0014] S21. Vertically translating the step front edge line of the spiral staircase to the starting floor by one step height to obtain the spatial position of the step rear edge line, and then vertically translating by one vertical thickness of the stair plate to obtain the spatial position of the bottom plate generatrix;

[0015] S22. Setting the inner and outer circumferential vertical poles on the extension lines of the horizontal projection lines of the step front edge lines and offsetting the same side of the step front edge line, and using the inner and outer circumferential vertical poles to calibrate the height and support the radial horizontal poles, so that each radial horizontal pole is located below the corresponding bottom plate generatrix and the center line passes through the center point of the spiral staircase, and the radial horizontal poles, the inner and outer circumferential vertical poles form a portal frame to support the staircase formwork;

[0016] S3, connecting the stabilizing rods between the inner vertical rods and the outer vertical rods, respectively;

[0017] S4, finally, laying the stair formwork on the radial horizontal rods.

[0018] The application also provides a formwork system for cast-in-situ concrete spiral stairs, comprising:

[0019] The radial horizontal rods have a plurality of horizontal arrangements corresponding to the bottom plate generatrixes, the center line of the radial horizontal rods is vertically aligned with the tread front edge line, and the two ends of the radial horizontal rods are longer than the tread front edge line;

[0020] The inner vertical rods are located on the inner side of the inner circular arc of the spiral stairs, have a plurality of vertical arrangements corresponding to the radial horizontal rods of the spiral stairs, and the horizontal projection of each inner vertical rod deviates from the horizontal projection of the center line of the corresponding radial horizontal rod in the clockwise or counterclockwise direction of the inner circular arc;

[0021] The outer vertical rods are located on the outer side of the outer circular arc of the spiral stairs, have a plurality of vertical arrangements corresponding to the inner vertical rods on the same side of the radial horizontal rods;

[0022] The inner vertical rods and the outer vertical rods are vertically fixed on the ground of the starting floor of the spiral stairs, the top part exceeds the corresponding tread by a certain height, the horizontal projection is circumferentially arranged in a spaced manner, and the inner vertical rod positioning circular arc line and the outer vertical rod positioning circular arc line concentrically changing in diameter are formed with the inner circular arc and the outer circular arc, the inner vertical rods and the outer vertical rods are used for height calibration of the tread front edge line, the tread rear edge line, the bottom plate generatrix, and the radial horizontal rods and support connection of the radial horizontal rods, so that each radial horizontal rod is located below the corresponding bottom plate generatrix and the center line passes through the center point of the spiral stairs;

[0023] Each radial horizontal rod, inner vertical rod, and outer vertical rod forms a door-shaped support for supporting the stair bottom formwork;

[0024] The height difference between the center line of the radial horizontal rod and the bottom plate generatrix = the radial horizontal rod radius + the radial keel height + the vertical thickness of the stair bottom formwork;

[0025] Stabilizing rods are arranged between adjacent inner vertical rods and adjacent outer vertical rods to ensure the stability of the spiral stair formwork system.

[0026] As a further improvement of the application, a radial keel is further arranged on the radial horizontal rod, the top part of the radial keel has a slope inclined surface for laying and fixing the stair bottom formwork.

[0027] As a further improvement of the application, it further comprises:

[0028] The stair bottom formwork is in the shape of a sector, has a plurality of stair bottom formworks, each step of the spiral stair is arranged with a stair bottom formwork, the stair bottom formwork is fixed on the radial keel of the radial horizontal rod, is arranged obliquely, and the horizontal projection is the same as the tread shape of the spiral stair step;

[0029] The inner side formwork and the outer side formwork are both in the shape of a circular arc, the radii of the curved surfaces of the inner side formwork and the outer side formwork are the same as the inner arc radius and the outer arc radius of the spiral stair respectively, the bottoms of the inner side formwork and the outer side formwork are supported on the radial keel, and the outer sides of the inner side formwork and the outer side formwork are fixed to the outer side of the bottom formwork;

[0030] The inner side formwork, the outer side formwork and the bottom formwork jointly enclose a cavity for pouring concrete;

[0031] The step vertical formwork is arranged vertically on the outer side of the step front edge line, and the two ends are fixedly connected with the inner side formwork and the outer side formwork respectively;

[0032] The first auxiliary assembly is arranged on the back side of the inner side formwork opposite to the outer side formwork, and provides horizontal support for the inner side formwork and the outer side formwork; the first auxiliary assembly comprises vertical square wood and inclined support square wood;

[0033] The second auxiliary assembly is arranged on the outer side top and the outer side bottom of the step vertical formwork, and the two ends are fixedly connected with the inner side formwork and the outer side formwork respectively, and is used for providing horizontal support for the step vertical formwork.

[0034] As a further improvement of the present application, the stabilizing rods comprise sweeping rods, connecting rods and inclined support rods;

[0035] The sweeping rods are connected at the bottom ends of adjacent inner circumferential vertical rods, the bottom ends of adjacent outer circumferential vertical rods and the bottom ends of the inner circumferential vertical rods and the outer circumferential vertical rods connected by the same radial horizontal rod;

[0036] The connecting rods are connected at the top ends of adjacent inner circumferential vertical rods and the top ends of adjacent outer circumferential vertical rods;

[0037] The inclined support rods are cross-connected between adjacent inner circumferential vertical rods, between adjacent outer circumferential vertical rods and between the inner circumferential vertical rods and the outer circumferential vertical rods connected by the same horizontal radial rod.

[0038] As a further improvement of the present application, the length of the straight line edge of the stair bottom formwork in the shape of a sector is equal to the width of the stair board, the length of the inner side arc of the stair bottom formwork is equal to the length of the horizontal projection of the inner arc / Cosθ, and the length of the outer side arc of the stair bottom formwork is equal to the length of the horizontal projection of the outer arc / Cosθ; wherein θ is the stair board inclination angle at the inner arc and the outer arc of the spiral stair, and is calculated and determined according to the step height and the lengths of the inner arc and the outer arc.

[0039] As a further improvement of the present application, the inner side template and the outer side template are both made of multi-layer plywood and are processed by bending, and the inner recessed surface of the inner side template and the outer side template is provided with a plurality of grooves along the vertical direction.

[0040] As a further improvement of the present application, the radial keel and the radial horizontal rod are fixedly connected through a connecting assembly.

[0041] Compared with the prior art, the present application has the following beneficial effects:

[0042] (1) The cast-in-place concrete spiral stair formwork method and template system provide an accurate, reliable, simple and efficient line positioning and formwork method for cast-in-place concrete spiral stair construction, which can improve the construction quality of the cast-in-place concrete spiral stair, reduce the construction difficulty and shorten the construction period.

[0043] (2) The present application uses the front edge line of the spiral stair step as the reference line for line positioning, converts the spatial curved surface line positioning of the spiral stair into the line positioning of multiple straight line segments, and simultaneously decomposes the spatial line positioning of the step front edge line into two steps of horizontal plane line positioning and height line positioning, thereby reducing the difficulty of line positioning of the spiral stair and improving the accuracy of line positioning.

[0044] (2) The template system proposed by the present application has simple and clear stress, safe and reliable structure. The radial horizontal rod position of the main bearing rod is vertically aligned with the step front edge line, which is beneficial to improve the formwork setting accuracy and reduce the line positioning and formwork setting error. The formwork support setting and line positioning are cooperated synchronously, and the line positioning work is simple and easy to operate.

[0045] (4) The multiple fan-shaped plane templates are used to replace the stair bottom curved surface template, and the template processing and manufacturing are convenient and easy to install. Since the radial keel is the stair bottom bus, after the fan-shaped bottom template is fixed with the radial keel, the stair bottom curved surface shape can be automatically fitted. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 It is a name diagram of each part of the spiral stair;

[0047] Figure 2 It is an elevation view of the spiral stair;

[0048] Figure 3 It is a plan view of the spiral stair;

[0049] Figure 4 It is a plan view of the formwork support in the cast-in-place concrete spiral stair formwork method and template system of the present application;

[0050] Figure 5 It is a radial section view of the formwork support and the template in the cast-in-place concrete spiral stair formwork method and template system of the present application;

[0051] Figure 6 This is a partial plan view of the formwork and formwork support in a formwork system for cast-in-place concrete spiral staircases according to the present invention.

[0052] Figure 7 This is an unfolded view of the outer elevation of the formwork and formwork support in a formwork system for cast-in-place concrete spiral staircases according to the present invention.

[0053] Figure 8 This is a development view of the outer formwork elevation of a cast-in-place concrete spiral staircase formwork system according to the present invention.

[0054] Figure 9 This is a horizontal cross-sectional view of the outer formwork in a cast-in-place concrete spiral staircase formwork system according to the present invention.

[0055] Figure 10 This is a cross-sectional view of the connection between the radial horizontal bar and the radial keel in a formwork system for a cast-in-place concrete spiral staircase according to the present invention.

[0056] In the diagram: 1. Step; 2. Stair tread; 3. Staircase bottom surface; 4. Tread surface; 5. Riser surface; 6. Leading edge line of step; 7. Rear edge line of step; 8. Base plate generatrix; 9. Step height; 10. Vertical thickness of stair tread; 11. Starting floor; 12. Arrival floor; 13. Inner side of the staircase; 14. Outer side of the staircase; 15. Center point of the spiral staircase; 16. Inner arc; 17. Outer arc; 18. Inner circumferential upright positioning arc; 19. Outer circumferential upright positioning arc; 20. Inner circumferential upright; 21. 21. Outer perimeter uprights; 22. Radial horizontal bars; 23. Inner perimeter upright connecting bars; 24. Outer perimeter upright connecting bars; 25. Inner perimeter circumferential sweeping bars; 26. Outer perimeter circumferential sweeping bars; 27. Radial sweeping bars; 28. Diagonal bracing bars; 29. ​​Radial keel; 30. Bottom formwork; 31. Inner side formwork; 32. Outer side formwork; 33. Vertical square timber; 34. Diagonal bracing square timber; 35. Step upright formwork; 36. Horizontal square timber; 37. Groove; 40. Upper clamp; 41. Lower clamp; 42. Connecting bolts. Detailed Implementation

[0057] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. However, it should be noted that these embodiments are not intended to limit the present invention. Equivalent changes or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0058] It should be understood that, in this application, the horizontal plane of step 1 in the staircase is called the tread 4, and the vertical plane of step 1 is called the riser 5. The intersection line of each step 1's tread 4 and riser 5 is called the leading edge line 6, and the intersection line of each step 1's tread 4 and the riser 5 of the adjacent step 1 is called the trailing edge line 7. The intersection line of the plane containing the riser 5 and the bottom surface 3 of the staircase is called the base plate generatrix 8. The distance between the trailing edge line 7 and the base plate generatrix 8 is called the vertical thickness 10 of the stair slab. The names of the various parts of the staircase are as follows: Figure 1 As shown. The spiral staircase has a curved shape that ascends in a spiral. The projection of the spiral staircase onto the horizontal plane is an arc, the center of which is called the center point of the spiral staircase 15, the inner arc is called the inner arc 16, and the outer arc is called the outer arc 17. The elevation and plan of the spiral staircase are shown in the figures. Figure 2 , Figure 3 , Figure 2 The image shows the starting floor 11 and the ending floor 12 of the spiral staircase.

[0059] Please refer to Figures 4 to 10 The present invention illustrates a specific embodiment of a cast-in-place concrete spiral staircase formwork method and formwork system.

[0060] A method for formwork support of a cast-in-place concrete spiral staircase includes the following steps: S1, using the leading edge line 6 of the steps as the reference line for laying out and positioning the spiral staircase, firstly, locate the position of the leading edge line 6 of each step of the spiral staircase, and complete the laying out and positioning of the leading edge line 6 of each step; S11, determine the position of the center point 15 of the spiral staircase on the ground of the starting floor 11 and mark it, and draw the inner arc 16 and outer arc 17 of the spiral staircase based on the inner side 13 and outer side 14 of the staircase with the center point 15 of the spiral staircase as the center; S12, according to the position of the leading edge line 6 of the starting step of the spiral staircase and the rotation angle of each step 1, draw the horizontal projection line of the leading edge line 6 of each step on the ground of the starting floor 11; S13, extend the horizontal projection line of the leading edge line 6 of each step of the spiral staircase upward to the height of the step 1 from the floor, and the spatial position of the leading edge line 6 of the step can be obtained.

[0061] S2, Next, locate the position of the base plate generatrix 8 of the spiral staircase and support the inner circumferential uprights 20, outer circumferential uprights 21, and radial horizontal bars 22; S21, Vertically shift the leading edge line 6 of the spiral staircase steps one step height 9 towards the ground of the starting floor 11 to obtain the spatial position of the trailing edge line 7 of the steps, and then vertically shift it by one vertical thickness 10 of the stair slab to obtain the spatial position of the base plate generatrix 8; The vertical thickness 10 of the stair slab is the vertical distance from the trailing edge line 7 of the steps to the bottom surface 3 of the staircase; It should be noted that the positioning in steps S13 and S21 can both utilize the inner circumferential uprights 20 and outer circumferential uprights 21; S22, on the leading edge line 6 of the steps Inner circumferential uprights 20 and outer circumferential uprights 21 are respectively installed on the extended lines at both ends of the horizontal projection line and on the same side away from the leading edge line 6 of the step. The inner circumferential uprights 20 and outer circumferential uprights 21 are used to set the elevation and support the connecting radial horizontal bars 22, so that each radial horizontal bar 22 is located below the corresponding base plate generatrix 8 and its center line passes through the center point 15 of the spiral staircase. The radial horizontal bars 22, inner circumferential uprights 20 and outer circumferential uprights 21 together form a gate-shaped bracket to support the staircase template; S3, stabilizer bars are connected between the inner circumferential uprights 20 and between the outer circumferential uprights 21 respectively; S4, finally, the staircase template is laid on the radial horizontal bars 22.

[0062] The present invention also provides a formwork system for a cast-in-place concrete spiral staircase, comprising: a radial horizontal bar 22, having multiple bars, arranged horizontally below the base plate generatrix 8 of each level, the center line of the radial horizontal bar 22 being vertically aligned with the front edge line 6 of the step, and both ends of the radial horizontal bar 22 being longer than the front edge line 6 of the step.

[0063] The inner circumferential uprights 20 are located inside the inner arc 16 of the spiral staircase. Multiple uprights are arranged vertically, each corresponding to one of the radial horizontal bars 22 of the spiral staircase. The horizontal projection of each inner circumferential upright 20 deviates from the horizontal projection of the corresponding radial horizontal bar 22's centerline in a clockwise or counterclockwise direction along the inner arc 16. The distance by which the center of the inner circumferential upright 20 deviates from the corresponding step's leading edge line 6 is equal to the radius of the inner circumferential upright 20 plus the radius of the radial horizontal bar 22. The outer circumferential uprights 21 are located outside the outer arc 17 of the spiral staircase. Multiple outer circumferential uprights are arranged vertically on the same side of the radial horizontal bars 22, each corresponding to one of the inner circumferential uprights 20. The distance by which the center of the outer circumferential upright 21 deviates from the corresponding step's leading edge line 6 is equal to the radius of the outer circumferential upright 21 plus the radius of the radial horizontal bar 22. Both the inner circumferential uprights 20 and the outer circumferential uprights 21 are vertically fixed on the ground of the starting floor 11 of the spiral staircase. Their tops exceed the corresponding steps 1 by a certain height. Their horizontal projections are arranged in a circumferential pattern, forming positioning arc lines 18 and 19 of the inner circumferential uprights 20 and the outer circumferential uprights 21, respectively, which are concentric with the inner arc 16 and the outer arc 17. The inner circumferential uprights 20 and the outer circumferential uprights 21 are used to mark the height of the front edge line 6 of the step, the rear edge line 7 of the step, the base plate generatrix 8 and the radial horizontal bar 22, and to support and connect the radial horizontal bar 22, so that each radial horizontal bar 22 is located below the corresponding base plate generatrix 8 and its center line passes through the center point of the spiral staircase.

[0064] It is important to understand that each radial horizontal bar 22, inner circumferential vertical bar 20, and outer circumferential vertical bar 21 together form a portal frame to support the stair bottom formwork 30. The height difference between the centerline of the radial horizontal bar 22 and the base plate generatrix 8 equals the radius of the radial horizontal bar 22 + the height of the radial joists 29 + the vertical thickness of the stair bottom formwork 30. Stabilizing bars are provided between adjacent inner circumferential vertical bars 20 and adjacent outer circumferential vertical bars 21 to ensure the stability of the spiral stair formwork system. Radial joists 29 are also provided on the radial horizontal bar 22. The top of the radial joists 29 has a sloping surface to match the inclined bottom formwork 30, used for laying and fixing the stair bottom formwork 30.

[0065] It also includes: a staircase bottom template 30, which is fan-shaped and consists of multiple pieces. Each step 1 of the spiral staircase corresponds to one staircase bottom template 30, which is fixed to the radial keel 29 of the radial horizontal bar 22, placed at an angle, and its horizontal projection has the same shape as the tread surface 4 of the spiral staircase step 1; the inner template 31 and the outer template 32 are both arc-shaped curved surface structures. The radius of the curved surface of the inner template 31 and the outer template 32 is the same as the radius of the inner arc 16 and the radius of the outer arc 17, respectively. The bottom of the inner template 31 and the outer template 32 are both supported on the radial keel 29 and fixed to the outside of the bottom template 30 in opposite directions; the vertical height of the inner and outer templates 32 is: the vertical thickness of the bottom template 30 + the vertical thickness of the stair tread 10 + the step height 9 + the excess height. The bottom of the inner template 31 and the outer template 32 are supported on the radial keel 29 and fixed to the bottom template 30 with steel nails. The inner formwork 31, outer formwork 32, and bottom formwork 30 together enclose the cavity for pouring concrete; the step formwork 35 is vertically arranged outside the front edge line 6 of the step, and its two ends are fixedly connected to the inner formwork 31 and outer formwork 32 respectively; it is rectangular in shape, with a height equal to the step height 9 and a length equal to the width of the stair tread 2. The top of the step formwork 35 is flush with the tread surface 4 of the step 1, and the bottom is suspended.

[0066] Specifically, the first auxiliary component includes vertical square timber 33 and diagonal bracing square timber 34, arranged on the opposite sides of the inner template 31 and the outer template 32, providing horizontal support for the inner template 31 and the outer template 32; the bottom of the vertical square timber 33 is fixed to the radial keel 29, and the sides are fixed to the inner and outer templates 32. The bottom of the diagonal bracing square timber 34 is fixed to the radial keel 29, and the top is fixed to the vertical square timber 33. The second auxiliary component is horizontal square timber 36, arranged at the top and bottom of the outer side of the step template 35, and its two ends are fixedly connected to the inner template 31 and the outer template 32 respectively, for providing horizontal support for the step template 35.

[0067] It should be understood that the stabilizer bar includes a ground sweeping bar, a connecting bar, and a diagonal brace 28; the ground sweeping bar is connected to the bottom end of the adjacent inner circumferential upright bar 20, the bottom end of the adjacent outer circumferential upright bar 21, and the bottom end of the inner circumferential upright bar 20 and the outer circumferential upright bar 21 connected by the same radial horizontal bar 22; it includes an inner circumferential ground sweeping bar 25, an outer circumferential ground sweeping bar 26, and a radial ground sweeping bar 27; the connecting bar is connected to the top end of the adjacent inner circumferential upright bar 20 and the top end of the adjacent outer circumferential upright bar 21; it includes an inner circumferential upright bar connecting bar 23 and an outer circumferential upright bar connecting bar 24; the diagonal brace 28 is cross-connected between adjacent inner circumferential upright bars 20, between adjacent outer circumferential upright bars 21, and between the inner circumferential upright bars 20 and the outer circumferential upright bars 21 connected by the same horizontal radial bar.

[0068] It is important to understand that the length of the straight side of the fan-shaped section of the stair bottom template 30 is equal to the width of the stair tread 2. The width of the stair tread 2 is the length of the leading edge line 6 of the step. The lengths of the inner and outer arcs of the stair bottom template 30 are respectively equal to: the horizontal projection length of the inner and outer arcs / Cosθ; where θ is the inclination angle of the stair tread 2 at the inner and outer arcs 17 of the spiral staircase, which is calculated and determined based on the step height 9 and the lengths of the inner and outer arcs. Both the inner template 31 and the outer template 32 are made of multi-layer plywood through bending processing, and the concave surfaces of the inner template 31 and the outer template 32 are provided with several grooves 37 spaced vertically along the inner side to allow the inner template 31 and the outer template 32 to be bent and shaped, eliminating the stress formed during the bending process.

[0069] In this embodiment, the radial keel 29 and the radial horizontal bar 22 are fixedly connected by a connecting assembly. Steel clamps are used to fix the radial keel 29 to the radial horizontal bar 22. The connecting assembly includes an upper clamp 40, a lower clamp 41, and a connecting bolt 42. The upper clamp 40 has a cavity for fixing the radial keel 29, and the lower clamp 41 has a recess that fits tightly against the outer surface of the radial horizontal bar 22. The connecting bolt 42 is used to fix the upper clamp 40 and the lower clamp 41 together, so that the radial keel 29 can be fixedly clamped onto the radial horizontal bar 22 by the upper clamp 40 and the lower clamp 41.

[0070] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for formwork support of a cast-in-place concrete spiral staircase, characterized in that, Includes the following steps: S1, using the leading edge line of the step as the reference line for the layout and positioning of the spiral staircase, first locate the position of the leading edge line of each step of the spiral staircase, and complete the layout and positioning of the leading edge line of each step. S11. Determine the location of the center point of the spiral staircase on the ground of the starting floor. Using the center point of the spiral staircase as the center, draw the inner and outer arcs of the spiral staircase. S12. Based on the position of the leading edge line of the starting step of the spiral staircase and the rotation angle of each step, draw the horizontal projection line of the leading edge line of each step on the ground floor of the starting floor. S13, the horizontal projection line of the leading edge line of each step of the spiral staircase is drawn upward to the height of the step from the floor, thus obtaining the spatial position of the leading edge line of the step. S2, Next, locate the position of the base plate of the spiral staircase and support the inner circumferential uprights, outer circumferential uprights and radial horizontal bars; S21. Vertically shift the front edge line of the spiral staircase step towards the ground of the starting floor by one step height to obtain the spatial position of the rear edge line of the step. Then vertically shift it by one vertical thickness of the stair slab to obtain the spatial position of the base plate generatrix. S22, inner and outer circumferential uprights are respectively supported on the two ends of the horizontal projection line of the front edge of the step and on the same side away from the front edge of the step. The inner and outer circumferential uprights are used to mark the height and support the connecting radial horizontal bars, so that each radial horizontal bar is located below the corresponding base plate generatrix and the center line passes through the center point of the spiral staircase. The radial horizontal bars, inner and outer circumferential uprights together form a gate-shaped support to support the staircase template. S3, connecting stabilizing bars between the inner and outer circumferential uprights respectively; S4. Finally, lay the stair formwork on the radial horizontal bar.

2. A formwork system for a cast-in-place concrete spiral staircase, based on the formwork support method for a cast-in-place concrete spiral staircase as described in claim 1, characterized in that, include: A radial horizontal bar, consisting of multiple bars, is arranged horizontally below the base plate generatrix of each level. The center line of the radial horizontal bar is vertically aligned with the leading edge line of the step, and both ends of the radial horizontal bar are longer than the leading edge line of the step. The inner circumferential uprights are located on the inner side of the inner arc of the spiral staircase. There are multiple uprights, which are arranged vertically in a one-to-one correspondence with the radial horizontal bars of the spiral staircase. The horizontal projection of each inner circumferential upright is offset from the horizontal projection of the center line of the corresponding radial horizontal bar in a clockwise or counterclockwise direction along the inner arc. The outer circumferential uprights are located on the outer side of the outer arc of the spiral staircase. There are multiple uprights, and they are arranged vertically on the same side of the radial horizontal bar, corresponding one to one with the inner circumferential uprights. Both the inner and outer circumferential uprights are vertically fixed on the ground of the starting floor of the spiral staircase, with their tops extending beyond the tops of the corresponding steps. Their horizontal projections are arranged in a circumferential, spaced pattern. They are used to mark the height of the front edge line of the step, the rear edge line of the step, the base plate generatrix, and the radial horizontal bar, and to support and connect the radial horizontal bar, so that each radial horizontal bar is located below the corresponding base plate generatrix and its centerline passes through the center point of the spiral staircase. Each of the radial horizontal bars, inner circumferential vertical bars, and outer circumferential vertical bars together forms a portal-shaped support for supporting the bottom formwork of the stairs; The height difference between the centerline of the radial horizontal bar and the base plate generatrix = radial horizontal bar radius + radial keel height + vertical thickness of the stair bottom formwork; Stabilizing bars are installed between adjacent inner circumferential uprights and between adjacent outer circumferential uprights to ensure the stability of the spiral staircase formwork system.

3. The formwork system for a cast-in-place concrete spiral staircase according to claim 2, characterized in that, The radial horizontal bar is also provided with radial keel, and the top of the radial keel has a sloping surface for laying and fixing the bottom template of the stairs.

4. The formwork system for a cast-in-place concrete spiral staircase according to claim 2, characterized in that, Also includes: The bottom template of the staircase is fan-shaped and consists of multiple pieces. Each step of the spiral staircase is provided with a bottom template, which is fixed on the radial keel of the radial horizontal bar, placed at an angle, and its horizontal projection is the same as the tread shape of the spiral staircase step. Both the inner and outer templates are arc-shaped curved surface structures. The arc radius of the inner and outer templates is the same as the inner and outer arc radius of the spiral staircase, respectively. The bottom of both the inner and outer templates is supported on the radial keel and fixed to the outside of the bottom template. The inner template, outer template, and bottom template together enclose the cavity for pouring concrete; The step template is vertically arranged outside the front edge of the step, and its two ends are fixedly connected to the inner template and the outer template, respectively. A first auxiliary component is arranged on the opposite side of the inner template and the outer template to provide horizontal support for the inner template and the outer template; the first auxiliary component includes vertical square timber and diagonal bracing square timber; The second auxiliary component is arranged at the top and bottom of the outer side of the step template, and its two ends are fixedly connected to the inner template and the outer template respectively, for providing horizontal support for the step template.

5. The formwork system for a cast-in-place concrete spiral staircase according to claim 2, characterized in that, The stabilizer bar includes a ground sweeping bar, a connecting bar, and a diagonal brace; The sweeping rod is connected to the bottom end of the adjacent inner circumferential upright, the bottom end of the adjacent outer circumferential upright, and the bottom ends of the inner and outer circumferential uprights connected by the same radial horizontal rod. The connecting rod is connected to the top of the adjacent inner circumferential upright and the top of the adjacent outer circumferential upright; The diagonal bracing is cross-connected between adjacent inner circumferential uprights, between adjacent outer circumferential uprights, and between inner and outer circumferential uprights connected by the same radial horizontal bar.

6. The formwork system for a cast-in-place concrete spiral staircase according to claim 2, characterized in that, The length of the straight side of the fan-shaped section of the bottom formwork of the staircase is equal to the width of the stair slab, which is the length of the front edge of the step. The lengths of the inner and outer arcs of the bottom formwork of the staircase are equal to: the horizontal projection length of the inner and outer arcs / Cosθ; where θ is the inclination angle of the stair slab at the inner and outer arcs of the spiral staircase, which is calculated and determined based on the step height and the lengths of the inner and outer arcs.

7. The formwork system for a cast-in-place concrete spiral staircase according to claim 2, characterized in that, Both the inner and outer templates are made of multi-layer plywood through bending and shaping, and the concave surfaces of the inner and outer templates are provided with several grooves spaced vertically.

8. The formwork system for a cast-in-place concrete spiral staircase according to claim 3, characterized in that, The radial keel and the radial horizontal bar are fixedly connected by a connecting assembly.

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