A ladder beam structure with inclined bottom steps for large-span stairs and a method of using the structure

Abstract

The present invention discloses a sloping step beam structure for a large-span staircase and a method of using the structure, comprising a sloping step surface steel bar skeleton and a cement coating attached to the sloping step surface steel bar skeleton; the sloping step surface steel bar skeleton comprises a sloping step surface steel bar skeleton frame, a longitudinal steel bar group arranged on the sloping step surface steel bar skeleton frame, and stirrups tied to the sloping step surface steel bar skeleton frame; the sloping step surface steel bar skeleton has a trapezoidal sloping step surface steel bar cage in cross section, the bottom end of the cross section is an inclined surface, and the horizontal angle of the inclined surface is β; the cement coating is cast as a whole with the sloping step surface steel bar skeleton to form a sloping step beam structure of an upper step surface and a lower step surface. The calculated span of the stair slab is reduced, and the problem that the slab of a large-span cast-in-place concrete slab staircase is too thick and affects the net height is solved. The load of the large-span cast-in-place concrete slab staircase can be dispersed and transmitted, and the problem that the slab of a large-span cast-in-place concrete slab staircase is too thick and affects the net height is solved.

Description

Technical Field

[0001] The invention relates to a slanted-bottom step beam structure for large-span stairs and a use method thereof, and is particularly suitable for the slanted-bottom step beam structure of a large-span cast-in-place concrete slab-type scissors staircase structure of a slab-type staircase structure in a small-story building. Background Art

[0002] At present, most of the slab-type stairs in large-span commercial buildings adopt thick plate structures or add rectangular ladder beams and intermediate ladder columns in the middle of the stair section. These practices can meet the requirements for the net height when the span is small and the floor height is high. However, when the span is large and the floor height is small, such as when the span is greater than 7.5 meters and the floor height is less than 5.1 meters, the net height of the stairs cannot meet the requirements due to the thick thickness and deflection of the stair section plate or the high height of the rectangular ladder beam in the middle of the stair section plate. For example, when using traditional rectangular beams, the beam width is one step width, but the height needs to reach 300~400mm. When the floor height is small, the net height under the beam cannot meet the design requirements, affecting the use of the building function. Summary of the invention

[0003] Technical problem: The purpose of the present invention is to overcome the shortcomings of the prior art and to provide a large-span staircase with a slanted bottom tread beam structure and a method of use which has a simple structure, light weight, small deflection, and is material-saving and can adapt to large-span cast-in-place concrete scissor stairs with large spans and small floor heights.

[0004] Technical solution: The present invention discloses a sloping ladder beam structure for a large-span staircase, comprising a sloping ladder surface steel bar skeleton and a cement coating attached to the sloping ladder surface steel bar skeleton; the sloping ladder surface steel bar skeleton comprises a sloping ladder surface steel bar skeleton frame, a longitudinal steel bar group arranged on the sloping ladder surface steel bar skeleton frame, and stirrups tied to the sloping ladder surface steel bar skeleton frame; the sloping ladder surface steel bar skeleton has a trapezoidal sloping ladder surface steel bar cage in cross section, the bottom end of the cross section is an inclined surface, and the horizontal angle of the inclined surface is β The cement sheathing body is cast together with the steel frame of the inclined bottom step surface to form the inclined bottom step beam structure of the upper step surface and the lower step surface.

[0005] The longitudinal steel bar group includes three parts: stress-bearing steel bars, erection steel bars, and connecting anchoring ends; the stress-bearing steel bars are composed of 4 steel bars, which are respectively arranged at the vertical projection positions of the erection steel bars at the inclined bottom; the erection steel bars are composed of 6 steel bars, of which four steel bars are arranged at intervals at the corner positions of the upper end surface of the inclined bottom step steel bar skeleton, and the other two erection steel bars are respectively added at the middle position of the lower step step surface and the middle section of the vertical surface on the lower step side of the inclined bottom step steel bar skeleton frame; the connecting anchoring ends are arranged at both ends of the cement sheathing body, and are composed of reserved steel bar sections of the longitudinal steel bar group.

[0006] The stirrups are formed by binding vertical stirrups, transverse stirrups and reinforcing bars. The length of the upper step surface of the stirrups is equal to 0.5 times the length of the lower step surface, and the length of the lower step surface is 270-280mm; the reinforcing bars are arranged perpendicular to the lower step surface, the upper end of the reinforcing bars is connected to the eighth steel bar in the erecting steel bars, and the lower end of the reinforcing bars is connected to the third steel bar in the load-bearing steel bars.

[0007] The stirrups tied to the inclined bottom ladder steel frame are arranged at a spacing of 100 mm in the longitudinal direction.

[0008] The reserved steel bar length of the longitudinal steel bar group is 200 mm.

[0009] The horizontal angle of the inclined surface at the bottom of the cross section of the inclined bottom ladder steel bar skeleton is β It is 28~30°.

[0010] The method of using the above-mentioned inclined bottom step ladder beam structure for large-span stairs is as follows:

[0011] The longitudinal steel bar group and stirrups are connected by binding to form a steel bar skeleton with an inclined bottom and a steel bar cage with a trapezoidal upper section, thus forming the skeleton of the inclined bottom tread ladder beam structure of the large-span staircase;

[0012] The inclined bottom tread steel reinforcement frame is placed in the template of the staircase flight, so that the inclined bottom tread steel reinforcement frame is located in the middle position of the staircase structure; then the top and bottom steel bars of the staircase flight slab are passed through the inclined bottom step ladder beam steel reinforcement cage frame, and the steel bars of the staircase flight slab are tied at the intersections of steel bars ①, ②, ③, and ④ in the inclined bottom step ladder beam, and the steel bars of the staircase flight slab and the inclined bottom tread steel reinforcement cage frame are connected by tying each steel bar to form a whole; after the steel bars of the staircase flight and the inclined bottom tread steel reinforcement frame are tied, they are poured together with concrete to wrap and form a concrete sheathing body of the entire staircase flight, and the staircase flight slab steel bars, the inclined bottom tread steel reinforcement frame and the concrete sheathing body are adhered together by concrete to form a staircase flight structure with an additional inclined bottom step ladder beam structure;

[0013] The connecting anchor ends at both ends of the inclined bottom tread steel frame are tied and connected with the steel bars inside the columns of the slab-type staircase structure, and then poured together with concrete to wrap them to form an overall rigid connection; when the staircase structure is loaded, the stair treads transfer the load to the inclined bottom step beam structure, and the inclined bottom step beam structure transfers the load to the columns of the slab-type staircase structure through the inclined bottom tread steel frame and the cement sheathing, and finally to the frame structure of the building.

[0014] Beneficial effects: The inclined bottom step ladder beam structure of the present invention divides the slab staircase into upper and lower sections, and the respective loads are transmitted to the column through the inclined bottom step ladder beam structure, reducing the calculated span of the stair section plate, solving the problem that the slab of a large-span cast-in-place concrete slab staircase is too thick and affects the net height, greatly saving the space at the bottom of the stair section, and meeting the net height requirements of stairs with smaller floor heights; and because there is no beam protruding in the middle of the stair section plate, the problem of affecting the net height due to the excessively high cross-section of the ladder beam when adding a ladder beam in the middle of the stair section is solved, thereby improving the appearance of the stairs. The main advantages compared with the existing technology are:

[0015] (1) It can solve the problem of heavy deadweight, large deflection or traditional beam-column influence on the net height of large-span, low-rise commercial building slab stairs. The inclined bottom step ladder beam structure arranged in the middle of the large-span staircase is used to disperse and transfer the load of the large-span cast-in-place concrete slab staircase, reducing the calculated span of the stair slab, thereby solving the problem of the large-span cast-in-place concrete slab staircase slab being too thick and affecting the net height, and solving the problem of the net height being affected by the excessively high cross-section of the ladder beam when adding a ladder beam in the middle of the stair segment.

[0016] (2) The stair tread beam adopts a step-shaped beam structure. The beam height does not exceed the step height, which greatly saves the space at the bottom of the stair section and can meet the clear height requirements of the stairs under the condition of smaller floor height. In addition, since there is no beam protruding in the middle of the stair section, the staircase looks better. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the side section structure of the present invention;

[0018] Figure 2 It is a front view structural schematic diagram of the present invention;

[0019] Figure 3 It is a schematic diagram of the positions of the erection steel bars and the stress steel bars of the present invention;

[0020] Figure 4 It is a schematic diagram of the stirrup structure of the present invention.

[0021] In the figure: 1 inclined bottom step surface reinforcement skeleton; 1-1 longitudinal reinforcement group; 1-1-1 stress-bearing reinforcement; 1-1-2 vertical reinforcement; 1-1-3 connecting anchor end; 1-2 stirrups; 1-2-1 vertical stirrups; 1-2-2 transverse stirrups; 1-2-3 reinforcing bars; 1-3 bottom inclined surface; 1-4 upper step surface; 1-5 lower step surface. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to the embodiments in the accompanying drawings:

[0023] The present invention discloses a sloping tread beam structure for a large-span staircase, which is mainly composed of a sloping tread surface steel bar skeleton 1 and a cement sheathing body 2. The cement sheathing body 2 is attached to the sloping tread surface steel bar skeleton 1; that is, the cement sheathing body 2 and the sloping tread surface steel bar skeleton 1 are cast as a whole, and the two are adhered together by cement to form the sloping tread beam structure.

[0024] The inclined bottom ladder surface steel bar skeleton 1 comprises an inclined bottom ladder surface steel bar skeleton frame, a longitudinal steel bar group 1-1 arranged on the inclined bottom ladder surface steel bar skeleton frame, and stirrups 1-2 tied to the inclined bottom ladder surface steel bar skeleton frame. The inclined bottom ladder surface steel bar skeleton 1 has a trapezoidal inclined bottom ladder surface steel bar cage in cross section, and the bottom end of the cross section is an inclined surface, and the horizontal angle of the inclined surface is β The horizontal angle of the inclined surface at the bottom of the cross section of the inclined bottom ladder steel frame 1 is β The cement coating 2 is cast as a whole with the inclined bottom step steel frame 1 to form the inclined bottom step ladder beam structure of the upper step ladder surface 1-4 and the lower step ladder surface 1-5. The stirrups 1-2 tied to the inclined bottom step steel frame frame are arranged at a spacing of 100mm in the longitudinal direction.

[0025] The longitudinal steel bar group 1-1 includes three parts: a stress-bearing steel bar 1-1-1, a frame steel bar 1-1-2, and a connecting anchor end 1-1-3; the stress-bearing steel bar 1-1-1 is composed of four steel bars of model HRB400, such as Figure 3 The numbers shown in the figure are steel bars ①, ②, ③, and ④, respectively, which are arranged at the vertical projection positions of the erection steel bars 1-1-2 at the inclined bottom; the erection steel bars 1-1-2 are composed of 6 steel bars of model HRB400, such as Figure 3 The numbers shown in the figure are steel bars ⑤, ⑥, ⑦, ⑧, ⑨, and ⑩, wherein the four steel bars ⑤, ⑥, ⑦, and ⑨ are arranged at intervals at the corners of the upper end surface of the inclined bottom step steel bar skeleton 1, the erection steel bars of the steel bar ⑧ are located between the steel bars ⑦ and ⑨, and the main function of the steel bar ⑧ is to strengthen the bearing capacity of the lower step step 1-5, and the erection steel bars of the steel bar ⑩ are arranged at the middle section of the vertical surface on the lower step side of the inclined bottom step steel bar skeleton frame, and the main function of the steel bar ⑩ is to strengthen the vertical force bearing capacity on the lower step side; the connecting anchor end 1-1-3 is arranged at both ends of the cement sheath 2, and is composed of the reserved steel bar section of the longitudinal steel bar group 1-1. The length of each side of the steel bar group 1-1 extending out of the cement sheath 2 is 20d in the horizontal section and 15d in the bending section, and d is the steel bar diameter of the longitudinal steel bar 1-1.

[0026] The stress-bearing steel bars 1-1-1 are composed of 4 steel bars, which are respectively arranged at the vertical projection positions of the erection steel bars 1-1-2 at the inclined bottom; the erection steel bars 1-1-2 are composed of 6 steel bars, of which four steel bars are arranged at intervals at the corner positions of the upper end surface of the inclined bottom step surface steel bar skeleton 1, and the other two erection steel bars 1-1-2 are respectively added at the middle position of the lower step step surface 1-5 and the middle position of the vertical surface of the lower step side of the inclined bottom step surface steel bar skeleton frame; the connection anchor end 1-1-3 is arranged at both ends of the cement sheath 2, and is composed of the reserved steel bar section of the longitudinal steel bar group 1-1. The reserved steel bar length of the longitudinal steel bar group 1-1 is 200mm.

[0027] The stirrups 1-2 are formed by binding vertical stirrups 1-2-1, transverse stirrups 1-2-2 and reinforcing bars 1-2-3, and the stirrups are made of HRB400 steel bars. The length of the upper step surface 1-4 of the stirrups 1-2 is equal to 0.5 times the length of the lower step surface 1-5, and the length of the lower step surface 1-5 is 270-280mm; the reinforcing bars 1-2-3 are arranged perpendicular to the lower step surface 1-5, the upper end of the reinforcing bars 1-2-3 is connected to the eighth steel bar in the erection steel bars 1-1-2, and the lower end of the reinforcing bars 1-2-3 is connected to the third steel bar in the force-bearing steel bars 1-1-1.

[0028] The reinforcing tie bar 1-2-3 is arranged perpendicular to the lower step surface 1-5, and its upper end is tied and connected to the erection steel bar 1-1-2 in the middle of the lower step surface 1-5, and its lower end is tied and connected to a erection steel bar 1-1-2 whose upper end connection point is at the projection position of the bottom inclined surface 1-3. The upper end of the reinforcing tie bar 1-2-3 is tied and connected to the eighth steel bar in the erection steel bar 1-1-2, and the lower end of the reinforcing tie bar 1-2-3 is tied and connected to the third steel bar in the force-bearing steel bar 1-1-1.

[0029] The present invention is used for the use of the inclined bottom step ladder beam structure of a large-span staircase:

[0030] The longitudinal steel bar group 1-1 and the stirrups 1-2 are connected by binding to form a sloping bottom step steel bar skeleton 1 with a sloping bottom section and a trapezoidal sloping bottom step steel bar cage with a trapezoidal top section, forming a skeleton of the sloping bottom step ladder beam structure of the large-span staircase;

[0031] The inclined bottom tread steel reinforcement frame 1 is placed in the template of the staircase flight, so that the inclined bottom tread steel reinforcement frame 1 is located in the middle position of the staircase structure; then the top and bottom steel bars of the staircase flight slab are passed through the inclined bottom step ladder beam steel cage frame 1, and the steel bars of the staircase flight slab are tied with the steel bars ①, ②, ③, and ④ in the inclined bottom step ladder beam at the intersection, and the steel bars of the staircase flight slab and the inclined bottom tread steel reinforcement cage frame are connected by tying each steel bar to form a whole; after the steel bars of the staircase flight and the inclined bottom tread steel reinforcement frame 1 are tied, they are poured together with concrete to wrap and form a concrete sheathing body of the entire staircase flight, and the staircase flight slab steel bars, the inclined bottom tread steel reinforcement frame 1 and the concrete sheathing body are adhered together by concrete to form a staircase flight structure with an inclined bottom step ladder beam structure added;

[0032] The connecting anchor ends 1-1-3 at both ends of the inclined bottom stair surface steel frame 1 are tied and connected with the steel bars inside the column of the slab-type staircase structure, and then poured together with concrete to wrap them to form an integral rigid connection; when the staircase structure is loaded, the stair tread transfers the load to the inclined bottom step ladder beam structure, and the inclined bottom step ladder beam structure transfers the load to the ladder column of the slab-type staircase structure through the inclined bottom stair surface steel frame 1 and the cement sheathing 2, and finally to the frame structure of the building.

Claims

1. A ladder beam structure with inclined bottom steps for a large-span staircase, characterized in that: It comprises a sloping bottom ladder surface steel bar skeleton (1) and a cement coating (2) attached to the sloping bottom ladder surface steel bar skeleton (1); the sloping bottom ladder surface steel bar skeleton (1) comprises a sloping bottom ladder surface steel bar skeleton frame, a longitudinal steel bar group (1-1) arranged on the sloping bottom ladder surface steel bar skeleton frame, and stirrups (1-2) tied to the sloping bottom ladder surface steel bar skeleton frame; the cross section of the sloping bottom ladder surface steel bar skeleton (1) is a trapezoidal sloping bottom ladder surface steel bar cage, the bottom end of the cross section is an inclined surface, and the horizontal angle of the inclined surface is β The cement coating (2) and the steel bar skeleton (1) of the inclined bottom step are cast as one body, forming the inclined bottom step ladder beam structure of the upper step ladder surface (1-4) and the lower step ladder surface (1-5); the longitudinal steel bar group (1-1) includes three parts: a stress-bearing steel bar (1-1-1), a frame steel bar (1-1-2), and a connecting anchor end (1-1-3); the stress-bearing steel bar (1-1-1) is composed of four steel bars of model HRB400, which are numbered as steel bars ①, ②, ③, and ④, respectively, and are arranged at the vertical projection position of the frame steel bar (1-1-2) at the inclined bottom; the frame steel bar (1-1-2) is composed of six steel bars of model HRB400. The steel bars are respectively numbered as steel bars ⑤, ⑥, ⑦, ⑧, ⑨, and ⑩, wherein the four steel bars ⑤, ⑥, ⑦, and ⑩ are arranged at intervals at the corner positions of the upper end surface of the inclined bottom step steel bar frame (1), the erection steel bars of the steel bar ⑧ are located between the steel bars ⑦ and ⑨, and the main function of the steel bar ⑧ is to strengthen the bearing capacity of the lower step step surface (1-5), and the erection steel bars of the steel bar ⑩ are arranged at the middle section of the vertical surface on the lower step side of the inclined bottom step steel bar frame, and the main function of the steel bar ⑩ is to strengthen the load-bearing capacity of the vertical surface on the lower step side; the connecting anchor ends (1-1-3) are arranged at both ends of the cement sheath (2), and are composed of the reserved steel bar sections of the longitudinal steel bar group (1-1).

2. The inclined bottom step beam structure for a large-span staircase according to claim 1, characterized in that: The stirrups (1-2) are formed by binding vertical stirrups (1-2-1), transverse stirrups (1-2-2) and reinforcing bars (1-2-3); the length of the upper step surface (1-4) of the stirrups (1-2) is equal to 0.5 times the length of the lower step surface (1-5); the length of the lower step surface (1-5) is 270-280 mm; the reinforcing bars (1-2-3) are arranged perpendicular to the lower step surface (1-5); the upper end of the reinforcing bars (1-2-3) is connected to the eighth steel bar in the erecting steel bars (1-1-2); and the lower end of the reinforcing bars (1-2-3) is connected to the third steel bar in the force-bearing steel bars (1-1-1).

3. The inclined bottom tread ladder beam structure for a large-span staircase according to claim 1, characterized in that: The stirrups (1-2) tied to the inclined bottom step steel frame are arranged at a spacing of 100 mm in the longitudinal direction.

4. The inclined bottom tread ladder beam structure for a large-span staircase according to claim 2, characterized in that: The reserved steel bar length of the longitudinal steel bar group (1-1) is 200 mm.

5. The inclined bottom tread ladder beam structure for a large-span staircase according to claim 1, characterized in that: The horizontal angle of the inclined surface at the bottom of the cross section of the inclined bottom stepped steel bar skeleton (1) is β It is 28~30°.

6. The method for using the inclined bottom tread ladder beam structure for a large-span staircase according to claim 1, characterized in that: The longitudinal steel bar group (1-1) and the stirrups (1-2) are connected by binding to form a sloping bottom step steel bar skeleton (1) with a sloping bottom cross section and a sloping bottom step steel bar cage with a trapezoidal top cross section, thereby forming a skeleton of the sloping bottom step ladder beam structure of the large-span staircase; The inclined bottom tread steel reinforcement frame (1) is placed in the template of the staircase, so that the inclined bottom tread steel reinforcement frame (1) is located in the middle of the staircase structure; then the top and bottom steel bars of the staircase slab are passed through the inclined bottom tread ladder beam steel reinforcement cage frame (1), and the steel bars of the staircase slab are tied to the intersections of the steel bars ①, ②, ③, and ④ in the inclined bottom tread ladder beam, and the steel bars of the staircase slab and the inclined bottom tread steel reinforcement cage frame are connected by tying each steel bar to form a whole; after the steel bars of the staircase and the inclined bottom tread steel reinforcement frame (1) are tied, they are poured together with concrete to form a concrete sheathing body of the entire staircase, and the staircase slab steel bars, the inclined bottom tread steel reinforcement frame (1) and the concrete sheathing body are adhered together by concrete to form a staircase structure with an additional inclined bottom tread ladder beam structure; The connecting anchor ends (1-1-3) at both ends of the inclined bottom tread steel bar skeleton (1) are tied and connected to the steel bars in the column of the slab-type staircase structure, and then poured together with concrete to wrap them to form an integral rigid connection; when the staircase structure is loaded, the stair tread transmits the load to the inclined bottom step ladder beam structure, and the inclined bottom step ladder beam structure transmits the load to the slab-type staircase structure column through the inclined bottom tread steel bar skeleton (1) and the cement sheathing body (2), and finally transmits the load to the frame structure of the building.

Images