External prestressed steel strand-concrete combined tread structure

Abstract

The utility model relates to an external prestressed steel strand-concrete combined step plate structure which comprises a flat-plate-shaped precast concrete step, pre-embedded steel bars are arranged at the two ends of the bottom face of the precast concrete step respectively, the top ends of the pre-embedded steel bars are embedded into the precast concrete step, and the bottom ends of the pre-embedded steel bars are exposed. Tensile rib plates are arranged at the upper ends and the lower ends of the embedded steel bars respectively, and the exposed ends of the embedded steel bars located at the two ends are connected through prestressed steel strands. The stair beam bearing steel parts are fixed on the stair beams and located at the two ends of the bottoms of the prefabricated concrete steps, and each stair beam bearing steel part comprises an L-shaped body, a grouting baffle and a stiffening rib, wherein the grouting baffle and the stiffening rib define a rectangular box body with an opening in the top; a reserved wire groove is formed in the top of the grouting baffle, the prestressed steel strand is embedded into the reserved wire groove, the bottom end of the embedded steel bar is located in a rectangular box defined by the grouting baffle, and concrete grouting materials are poured into the rectangular box. The utility model has the advantages of light weight, low installation precision requirement and high installation speed.

Description

Technical Field

[0001] The utility model relates to the technical field of prefabricated stairs, and particularly relates to an external prestressed steel strand-concrete composite tread plate structure. Background Technique

[0002] In the field of prefabricated buildings, the adoption of prefabricated stairs helps to improve the construction speed. In the prior art, the tread surface of prefabricated stairs usually adopts an L-shaped precast concrete tread surface. Bolts are pre-embedded at the bottom of the stair tread surface in advance, and the installation of the stair tread surface is completed by connecting the pre-embedded bolts with the steel plates protruding from the side surface of the stair beam. This stair installation structure requires high installation accuracy, and the installation accuracy is completely guaranteed by the accuracy of the pre-embedded bolts and the welding accuracy, without much installation adjustment amount, and the production and installation deviations cannot be digested. Moreover, two-way steel bars need to be arranged inside the precast concrete tread surface, so that the minimum thickness of the stair tread surface cannot be less than 80 mm, and the weight of a single stair tread surface exceeds 100 kg. It is very difficult for manpower to operate this structural design without installation machinery. Even if UHPC (ultra-high performance concrete) material is used to replace ordinary concrete to reduce the thickness of the tread surface structure, the cost is too high and it is not suitable for mass production applications. Content of the Utility Model

[0003] The utility model discloses an external prestressed steel strand-concrete composite tread plate structure, which uses a relatively thin flat plate as the stair tread, and forms a combined stress state with the prestressed steel strand by using the relatively thin flat plate to jointly bear the load, which can reduce the production difficulty of the tread, reduce the weight of the tread, and reduce the requirement for installation accuracy.

[0004] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0005] An external prestressed steel strand-concrete composite tread plate structure includes a precast concrete tread in the shape of a flat plate. Embedded steel bars are respectively arranged at both ends of the bottom surface of the precast concrete tread. The top ends of the embedded steel bars are embedded inside the precast concrete tread, and the bottom ends of the embedded steel bars are exposed. Tensile rib plates are respectively arranged at the upper and lower ends of the embedded steel bars, and the exposed ends of the embedded steel bars at both ends are connected by a prestressed steel strand.

[0006] Further, a mid-span embedded steel bar is arranged in the middle of the bottom surface of the precast concrete tread. The top end of the mid-span embedded steel bar is embedded inside the precast concrete tread, and the bottom end of the mid-span embedded steel bar is exposed. A tensile rib plate is arranged at the top end of the mid-span embedded steel bar, and the prestressed steel strand connecting the embedded steel bars at both ends is also connected to the mid-span embedded steel bar.

[0007] Further, the precast concrete tread is cast with high-strength concrete above C60.

[0008] Furthermore, anti-slip grooves are provided on the top surface of the precast concrete step.

[0009] Furthermore, the composite tread plate structure further includes beam support steel members arranged at both ends of the bottom of the precast concrete step. The beam support steel members are used to be fixed on the ladder beam. The beam support steel members include a body with an L-shaped cross-section, grouting baffles arranged on the top surface of the horizontal plate of the body and enclosing a rectangular box with an open top, and stiffening ribs connecting the grouting baffles and the body; a reserved wire groove with an open top is formed at the top of the grouting baffle parallel to and away from the vertical plate of the body, and the prestressed steel strand is embedded in the reserved wire groove. The bottom end of the embedded steel bar is located in the rectangular box enclosed by the grouting baffle, and concrete grouting material is poured into the rectangular box.

[0010] Furthermore, adjusting screws, grouting holes and vibrating holes are respectively provided on the horizontal plate of the body corresponding to the inner cavity of the rectangular box. The adjusting screws are perpendicular to and penetrate the horizontal plate of the body. A one-way valve for grouting or a detachable grouting hole plug is installed at the grouting hole, and a vibrating hole cover plate is installed in the vibrating hole.

[0011] Furthermore, the vibrating hole cover plate includes a sleeve and a top plate. The top of the sleeve is fixedly connected to the bottom of the top plate. The sleeve is hollow and open at the bottom. The sleeve is inserted into the vibrating hole, and the top plate covers the vibrating hole and is limited by the horizontal plate of the body.

[0012] Furthermore, the one-way valve for grouting includes a cylindrical valve body with a hollow interior. The outer wall of the valve body is provided with threads, and the inner wall of the grouting hole is provided with threads. A limiting baffle is provided on the outer wall of the valve body. A stepped groove is provided in the upper part of the inner cavity of the valve body. The inner diameter of the stepped groove is larger than the inner diameter of the inner cavity of the valve body. A retaining ring is arranged in the stepped groove. A spring is arranged in the inner cavity of the valve body below the retaining ring, and a steel ball is arranged in the inner cavity of the valve body below the spring.

[0013] Furthermore, a wire groove plug is provided at the reserved wire groove.

[0014] Furthermore, the composite tread plate structure further includes a perforated baffle. The perforated baffle is perpendicular to the precast concrete step and is arranged outside the grouting baffle at the lower part of the precast concrete step. The perforated baffle is fixedly installed on the grouting baffle through baffle installation screws and limit nuts.

[0015] The utility model uses a relatively thin flat plate as the stair tread, and forms a combined stress state with the prestressed steel strand to jointly bear the load. The tread of the flat plate can reduce the production difficulty compared with the L-shaped tread. After the tread becomes thinner, the weight of a single precast concrete step can be reduced by more than 50%; the designed composite tread plate structure of the utility model can complete the installation of the stair section by the method of installing first and then grouting. This method has a larger adjustment space for installation deviation and faster installation speed, and the requirements for the construction surface and construction accuracy are lower than those of the existing installation methods. Description of the Drawings

[0016] Figure 1 It is the front view of the small-span external prestressed steel strand-concrete composite tread slab structure;

[0017] Figure 2 It is Figure 1 the top view of;

[0018] Figure 3 It is the front view of the large-span external prestressed steel strand-concrete composite tread slab structure;

[0019] Figure 4 It is Figure 1 the partial enlarged view of the right end in;

[0020] Figure 5 It is Figure 1 the left view of;

[0021] Figure 6 It is the structural schematic diagram of the one-way valve for grouting;

[0022] Figure 7 It is the schematic diagram of the combination of the treads of the flight of stairs.

[0023] Explanation of the reference numerals in the attached drawings:

[0024] 1. Prefabricated concrete tread; 2. Embedded steel bar; 3. Prestressed steel strand; 4. Steel member for supporting the ladder beam; 5. Concrete grouting material; 6. Grouting baffle; 7. Reserved wire groove; 8. Adjusting screw; 9. One-way valve for grouting; 91. Valve body; 92. Limit baffle; 93. Step groove; 94. Retaining ring; 95. Spring; 96. Steel ball; 10. Baffle installation screw and limit nut; 11. Perforated baffle; 12. Anti-slip groove; 13. Wire groove plug; 14. Vibration hole cover plate; 15. Embedded steel bar at the mid-span. Specific implementation manners

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention.

[0026] This embodiment discloses an external prestressed steel strand-concrete composite tread slab structure, as Figures 1 to 5 shown, mainly including a prefabricated concrete tread 1, an embedded steel bar 2, a prestressed steel strand 3, a steel member 4 for supporting the ladder beam, and a concrete grouting material 5. Among them, the prefabricated concrete tread 1 is in the shape of a flat plate and is cast with high-strength concrete above C60. When casting, the mold is provided with concave and convex parts so that anti-slip grooves 12 are formed on the top surface of the prefabricated concrete tread 1 formed after casting. At least at both ends, the embedded steel bars 2 are inserted into the mold, and one end of the embedded steel bar 2 is embedded inside the prefabricated concrete tread 1. Figure 1Taking the shown direction as a reference, for the precast concrete step 1 with a relatively small span, embedded steel bars 2 can be provided only at both ends of the bottom of the precast concrete step 1; however, for the precast concrete step 1 with a relatively large span, as shown in Figure 3 , embedded steel bars 1 are provided at both ends and in the middle of the bottom of the precast concrete step 1. The one in the middle is the mid-span embedded steel bar 15. In this embodiment, two rows of embedded steel bars 1 are arranged at intervals along the length direction of the precast concrete step 1, and the embedded steel bars 1 in each row are connected by prestressed steel strands 3. In the case where there is a mid-span embedded steel bar 15 in the middle, the prestressed steel strands 3 in each row need to connect the embedded steel bars 1 at both ends and the mid-span embedded steel bar 15 together at the same time. For the embedded steel bars 2 at both ends, tensile rib plates are provided at the upper and lower ends of the embedded steel bars 2. For the mid-span embedded steel bar 15, tensile rib plates can be provided only at the top end. Whether it is the embedded steel bar 2 at both ends or the mid-span embedded steel bar 15, its top end is embedded inside the precast concrete step 1, while the lower end is exposed, and the prestressed steel strand 3 is fixed on the exposed end.

[0027] The combination of the precast concrete step 1, the embedded steel bar 2, and the prestressed steel strand 3 formed after the above casting needs to be assembled and fixed in position with the beam support steel part 4 of the ladder beam, and then the connection part is grouted to connect the two parts into one. The beam support steel part 4 of the ladder beam is provided at both ends below the above combination, and the beam support steel part 4 of the ladder beam needs to be welded and fixed on the ladder beam in advance. The structure of the beam support steel part 4 of the ladder beam is as shown in Figure 4 and Figure 5 , and mainly includes a main body, a grouting baffle 6, and stiffening ribs. The main body is composed of a horizontal plate and a vertical plate to form an L-shaped structure. On the top surface of the horizontal plate, a rectangular box with an open top is enclosed by four grouting baffles 6. The two grouting baffles 6 parallel to the vertical plate of the main body are temporarily called the first grouting baffle and the second grouting baffle. The one farther from the vertical plate of the main body is the first grouting baffle. Stiffening ribs are provided between the side of the first grouting baffle and the top of the horizontal plate of the main body, and stiffening ribs are provided between the second grouting baffle and the vertical plate of the main body. Among them, a reserved wire groove 7 with an open and concave opening is provided at the top of the first grouting baffle. When the combination and the beam support steel part 4 of the ladder beam are assembled, the bottom end of the embedded steel bar 2 at the end is placed inside the rectangular box enclosed by the grouting baffle 6, and the prestressed steel strand 3 is embedded in the reserved wire groove 7. After their relative positions are adjusted, concrete grouting material 5 is poured into the rectangular box. During the pouring process, the height of the concrete pouring can be observed through the reserved wire groove 7. After the pouring reaches the height of the reserved wire groove 7, the reserved wire groove 7 can be temporarily blocked, and the grouting continues until it is flush with the top surface of the rectangular box. After the grouting is completed, the reserved wire groove 7 is blocked with a wire groove plug 13.

[0028] Further optimized design, in order to facilitate the adjustment of the relative position between the above-mentioned combination and the ladder beam supporting steel member 4, this embodiment also provides an adjustment screw 8 on the horizontal plate of the ladder beam supporting steel member 4 body, and the adjustment screw 8 is vertical and penetrates the horizontal plate of the body and is inserted into the inner cavity of the rectangular box. When the above-mentioned combination is placed on the ladder beam supporting steel member 4, the adjustment screw 8 is first turned to move its position downward to leave a height space for the embedded steel rod 2 to be embedded in the rectangular box. After the combination is moved so that the front, back, left, and right directions of the combination reach the theoretical position, the adjustment screw 8 is turned to move it upward, and the adjustment screw 8 is used to support the bottom of the embedded steel rod 2 to adjust the combination to the theoretical elevation to complete the leveling.

[0029] To further optimize the design and facilitate grouting and vibration in the rectangular box, in this embodiment, grouting holes and vibration holes are respectively provided on the horizontal plate of the main body corresponding to the inner cavity of the rectangular box. A one-way valve 9 for grouting can be installed at the grouting hole. The one-way valve 9 for grouting has the function of preventing backflow, and only allows concrete grouting material 5 to be poured from the outside to the inside of the rectangular box to prevent the grouting material from flowing back after grouting. You can also choose to install a grouting hole plugging cap in the grouting hole (with attached drawings omitted). First, insert the grouting pipe into the grouting hole, and then seal the grouting hole with a grouting hole plugging cap after the grouting is completed. This embodiment and the attached drawings are all illustrated by setting a one-way valve 9 for grouting in the grouting hole as an example. The structure of the one-way valve 9 for grouting is as follows: Figure 6 As shown, it mainly includes a cylindrical valve body 91 with a hollow interior. The outer wall of the valve body 91 is provided with threads, and the inner wall of the grouting hole is also provided with threads. The valve body 91 is connected to the grouting pipe through the threads of the outer wall, and the valve body 91 is also connected and fixed with the threads of the grouting hole through the threads of the outer wall. A hexagonal limit baffle 92 is provided on the circumference of the outer wall of the lower part of the valve body 91. The limit baffle 92 is used for wrench force and control of the depth of the valve body 91 in the grouting hole. A stepped groove 93 is provided on the upper part of the inner cavity of the valve body 91. The inner diameter of the stepped groove 93 is larger than the inner diameter of the inner cavity of the valve body 91, and a retaining ring 94 is provided in the stepped groove 93. A spring 95 is provided at the lower part of the retaining ring 94, and a steel ball 96 is provided at the lower part of the spring 95. The stepped groove 93 is used to clamp the retaining ring 94 and the steel ball 96, and the spring 95 presses the steel ball 96 to realize one-way fluid control.

[0030] A vibrating hole cover plate 14 is installed in the vibrating hole. The structure of the vibrating hole cover plate 14 is as follows: Figure 4 As shown, it includes a cylindrical sleeve and a top plate. The top of the sleeve is fixedly connected to the bottom of the top plate as a whole. The sleeve is hollow inside and open at the bottom. Before pouring grout, the sleeve is first inserted into the vibration hole. The top plate covers the vibration hole and is limited by the horizontal plate of the main body. After pouring concrete grouting material 5 into the rectangular box, the end of the external vibrating rod is inserted into the sleeve and vibrated close to the top plate to discharge the bubbles in the concrete grouting material 5.

[0031] The tread structure designed by the utility model is assembled into a staircase, such asFigure 7 As shown, a perforated baffle 11 can be provided at the front gap between the upper and lower adjacent tread plate structures for shielding, that is, the perforated baffle 11 is vertically provided on the lower side of each precast concrete tread 1 of each flight of stairs. Symmetrical holes are provided on the perforated baffle 11 and the adjacent grouting baffle 6, and the perforated baffle 11 is fixedly installed on the grouting baffle 6 with baffle installation screws and limit nuts 10.

[0032] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An external prestressed steel strand-concrete composite step slab structure, characterized in that: It includes precast concrete steps in a flat shape. At both ends of the bottom surface of the precast concrete steps, embedded steel bars are provided. The top ends of the embedded steel bars are embedded inside the precast concrete steps, and the bottom ends of the embedded steel bars are exposed. Tensile rib plates are provided at the upper and lower ends of the embedded steel bars respectively. The exposed ends of the embedded steel bars at both ends are connected by prestressed steel strands.

2. The external prestressed steel strand-concrete composite tread slab structure according to claim 1, characterized in that: A mid-span embedded steel bar is provided in the middle of the bottom surface of the precast concrete steps. The top end of the mid-span embedded steel bar is embedded inside the precast concrete steps, and the bottom end of the mid-span embedded steel bar is exposed. A tensile rib plate is provided at the top end of the mid-span embedded steel bar. The prestressed steel strands connecting the embedded steel bars at both ends are also connected to the mid-span embedded steel bar.

3. An external prestressed steel strand-concrete composite step slab structure according to claim 1, characterized in that: The precast concrete steps are cast with high-strength concrete above C60.

4. An external prestressed steel strand-concrete composite step slab structure according to claim 1, characterized in that: Anti-slip grooves are provided on the top surface of the precast concrete steps.

5. An external prestressed steel strand-concrete composite tread slab structure according to claim 1, characterized in that: The combined tread plate structure further includes beam support steel parts provided at both ends of the bottom of the precast concrete steps. The beam support steel parts are used to be fixed on the ladder beam. The beam support steel parts include a body with an L-shaped cross-section, a grouting baffle plate arranged on the top surface of the horizontal plate of the body and enclosing a rectangular box with an open top, and a stiffening rib connecting the grouting baffle plate and the body; a reserved wire groove with an open top is formed at the top of the grouting baffle plate parallel to and away from the vertical plate of the body. The prestressed steel strands are embedded in the reserved wire groove. The bottom ends of the embedded steel bars are located in the rectangular box enclosed by the grouting baffle plate, and concrete grouting material is poured into the rectangular box.

6. The external prestressed steel strand-concrete composite step slab structure according to claim 5, characterized in that: Adjusting screws, grouting holes and vibrating holes are respectively provided on the horizontal plate of the body corresponding to the inner cavity of the rectangular box. The adjusting screws are perpendicular to and penetrate the horizontal plate of the body. A one-way valve for grouting or a detachable grouting hole plug is installed at the grouting hole, and a vibrating hole cover plate is installed in the vibrating hole.

7. An external prestressed steel strand-concrete composite tread slab structure according to claim 6, characterized in that: The vibrating hole cover plate includes a sleeve and a top plate. The top of the sleeve is fixedly connected to the bottom of the top plate. The sleeve is hollow and has an open bottom. The sleeve is inserted into the vibrating hole, and the top plate covers the vibrating hole and is limited by the horizontal plate of the body.

8. The external prestressed steel strand-concrete composite step slab structure according to claim 6, characterized in that: The one-way valve for grouting includes a cylindrical valve body with a hollow interior. The outer wall of the valve body is provided with threads, and the inner wall of the grouting hole is provided with threads. A limiting baffle is provided on the outer wall of the valve body. A stepped groove is provided in the upper part of the inner cavity of the valve body. The inner diameter of the stepped groove is larger than the inner diameter of the inner cavity of the valve body. A retaining ring is arranged in the stepped groove. A spring is arranged in the inner cavity of the valve body below the retaining ring, and a steel ball is arranged in the inner cavity of the valve body below the spring.

9. The external prestressed steel strand-concrete composite step slab structure according to claim 5, characterized in that: A wire groove plug is provided at the reserved wire groove.

10. A structure of an external prestressed steel strand-concrete composite tread slab according to claim 5, characterized in that: The combined tread plate structure further includes a perforated baffle plate. The perforated baffle plate is perpendicular to the precast concrete steps and is arranged outside the grouting baffle plate at the lower part of the precast concrete steps. The perforated baffle plate is fixedly installed on the grouting baffle plate through baffle installation screws and limit nuts.

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