Post-tensioned prestressed small box girder lifting pedestal

Abstract

The utility model provides a post-tensioned prestressed small box girder lifting pedestal, which relates to the technical field of building construction, and comprises a plurality of lower supports, the lower supports are fixedly arranged on the ground, a plurality of embedded steel plate lower supports are arranged on the top surfaces of the lower supports, and support plates are arranged on the top surfaces of the embedded steel plate lower supports. The supporting plate is connected with an embedded steel plate supporting plate through a first lifting assembly, an embedded steel plate is arranged at the top of the embedded steel plate supporting plate, the lower support is connected with a movable end joint through a second lifting assembly, and the top of the movable end joint is connected with a box girder formwork bottom plate. The utility model has the beneficial effects that the tensioning tensile stress cracking of the bottom corner concrete at the beam end of the post-tensioned prestressed small box beam is avoided, the longitudinal and transverse gradient accuracy of the pre-embedded steel plate at the beam bottom is ensured, and the engineering quality of the upper structure of the bridge is further ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of building construction, especially to a post-tensioning prestressed small box girder lifting pedestal. BACKGROUND

[0002] In the tensioning process of the post-tensioning prefabricated prestressed small box girder, the beam body arches, the end of the beam body produces downward and inward displacement, the dead load of the beam body gradually transforms from the uniform load of the bottom plate to the concentrated stress at the beam end, and the redistribution of the stress at the beam end makes the beam end in a stress concentration state, which easily leads to the tensile stress cracking of the concrete at the bottom corner of the beam end.

[0003] The beam bottom embedded steel plate of the post-tensioning prefabricated prestressed small box girder is designed with different transverse and longitudinal slopes for each span beam plate, and whether the longitudinal and transverse slopes of the embedded steel plate can be accurately controlled is related to the installation elevation control accuracy of the beam plate, the stress state of the support installation, the connection quality of the transverse partition plate and the wet joint, and the construction process quality key control indicators such as the thickness of the bridge deck pavement.

[0004] The existing reinforced concrete frame pedestal is prone to cause the tensile stress cracking of the concrete at the bottom corner of the beam end due to the stress concentration at the beam end during the construction process of the post-tensioning prefabricated prestressed small box girder, and the longitudinal and transverse slopes of the embedded steel plate cannot be accurately controlled during the construction process of the beam bottom embedded steel plate, which brings many inconveniences to the quality control of subsequent construction.

[0005] The technical problem to be solved by the utility model is how to solve the above technical problems. CONTENT OF THE UTILITY MODEL

[0006] In order to solve the problems of the prior art, the utility model provides a post-tensioning prestressed small box girder lifting pedestal which can avoid the tensile stress cracking of the concrete at the bottom corner of the beam end, accurately control the longitudinal and transverse slopes of the embedded steel plate, and thus guarantee the engineering quality of the bridge superstructure.

[0007] The utility model adopts the technical scheme that: the utility model provides a post-tensioning prestressed small box girder lifting pedestal, which comprises a plurality of lower supports, the lower supports are fixedly arranged on the ground, a plurality of embedded steel plate lower supports are arranged on the top surface of the lower supports, and a support plate is arranged on the top surface of the embedded steel plate lower supports;

[0008] The support plate is connected with an embedded steel plate support plate through a first lifting assembly, and the embedded steel plate support plate is arranged on the top of the support plate;

[0009] The lower supports are connected with a movable end section through a second lifting assembly, and the movable end section is connected with a box girder formwork bottom plate on the top.

[0010] The lower support is an I-shaped steel structure, and each group of the end section lower support is provided with two symmetrical and parallel ones.

[0011] The embedded steel plate lower support is a " " shaped structure, is evenly arranged on the top surface of the end section lower support, and is arranged perpendicularly to the end section lower support.

[0012] The embedded steel plate lower support is located below the embedded hole opened on the bottom plate of the box girder formwork.

[0013] The movable end section reinforcing channel steel is arranged on both sides of the bottom plate of the box girder formwork and is connected to the movable end section.

[0014] The first lifting assembly and the second lifting assembly are the same in structure and each comprises an upper support at the top and a shell at the bottom.

[0015] The bottom of the shell is flat, and a vertical rod body is arranged above the shell, one side of the rod body is rotatably connected to a gear through a support, and a rack is slidably connected to the top of the gear.

[0016] A square hole is formed in one side of the rod body where the support is arranged, the square hole is in communication with the inside of the rod body, and one side of the rack where the teeth are arranged is engaged with the gear through the square hole.

[0017] The gear is coaxially and fixedly connected to a crank handle, and the crank handle is rotatably connected to the support.

[0018] A buckle is hingedly connected to the square hole of the shell through a hinge seat, the buckle is in a strip-shaped structure, a protrusion is arranged at the bottom of the outer end of the buckle, and the protrusion is clamped in the teeth of the gear.

[0019] A top bracket is fixedly connected to the top of the rack, the upper support is fixedly connected to the top of the top bracket, and an antiskid pad is arranged on the top surface of the upper support and the bottom surface of the shell.

[0020] A plurality of first lifting assemblies are evenly arranged, the upper support of the first lifting assembly is connected to the bottom of the embedded steel plate support plate, and the flat bottom of the shell is connected to the top of the support plate.

[0021] A plurality of second lifting assemblies are evenly arranged, the upper support of the second lifting assembly is connected to the bottom of the movable end section, and the flat bottom of the shell is connected to the top of the lower support.

[0022] The gear has a precision of 6-8 levels.

[0023] The utility model discloses a box girder formwork embedded steel plate lifting device, which can accurately control the position of the embedded steel plate at the beam end, avoid stress concentration when the beam end is tensioned, and reduce the risk of concrete tensile stress cracking.

[0024] The utility model discloses to the beam end tensioning stress concentration of existing box girder prefabrication pedestal causes the beam end bottom angle concrete cracking problem and the accurate control of beam bottom embedded steel plate are improved, avoid the tension tensile stress cracking of post-tensioned prestressed small box girder beam end bottom angle concrete, guarantee the longitudinal and transverse slope accuracy of beam bottom embedded steel plate, and further guarantee bridge superstructure engineering quality. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is the front view of the utility model.

[0026] Figure 2 It is the right view of the utility model.

[0027] Figure 3 It is the front view of the first lifting assembly of the utility model.

[0028] Figure 4 It is the right view of the first lifting assembly of the utility model.

[0029] Figure 5 It is the three-dimensional structure schematic view of the first lifting assembly of the utility model.

[0030] Among them, the sign is: 1, lower support;2, embedded steel plate lower support;3, support plate;4, first lifting assembly;5, embedded steel plate support plate;6, movable end section;7, second lifting assembly;8, non-slip mat;9, shell;10, crank handle;11, rack;12, top bracket;13, upper support;14, buckle;15, gear;16, box girder formwork bottom plate;18, movable end section reinforcing channel steel. DETAILED DESCRIPTION

[0031] In order to clearly show the technical features of the scheme, the following through specific implementation, the scheme is described.

[0032] Referring to Figures 1 to 5 The utility model discloses to the beam end tensioning stress concentration of existing box girder prefabrication pedestal causes the beam end bottom angle concrete cracking problem and the accurate control of beam bottom embedded steel plate are improved, avoid the tension tensile stress cracking of post-tensioned prestressed small box girder beam end bottom angle concrete, guarantee the longitudinal and transverse slope accuracy of beam bottom embedded steel plate, and further guarantee bridge superstructure engineering quality.

[0033] The support plate 3 is connected with the embedded steel plate support plate 5 through the first lifting assembly 4, the embedded steel plate support plate 5 is provided with an embedded steel plate at the top, and the lower support 1 is connected with the movable end section 6 through the second lifting assembly 7, and the movable end section 6 is connected with the box girder formwork bottom plate 16 at the top.

[0034] The first lifting assembly 4 and the second lifting assembly 7 are the same in structure and each include the upper support 13 at the top and the shell 9 at the bottom, the bottom of the shell 9 is flat, a vertical rod body is arranged at the top, a gear 15 is rotatably connected with the shell 9 through a support at one side of the rod body, a rack 11 is slidably connected with the shell 9 at the top, a square hole is formed in the side of the rod body, the square hole is communicated with the inside of the rod body, the rack 11 is engaged with the gear 15 through the square hole at the side of the gear 15, the gear 15 is coaxially fixedly connected with a crank 10, the crank 10 is rotatably connected with the support, the shell 9 is hingedly connected with a buckle 14 through a hinge seat above the square hole, the buckle 14 is in strip structure, a protrusion is arranged at the outer end of the bottom of the buckle 14, and the protrusion is clamped in the gear 15; the rack 11 is fixedly connected with a top bracket 12 at the top, the top bracket 12 is fixedly connected with the upper support 13 at the top, and the top surface of the upper support 13 and the bottom surface of the shell 9 are both pasted with anti-skid pads 8; the first lifting assembly 4 is uniformly arranged with a plurality of first lifting assemblies 4, the upper support 13 of the first lifting assembly 4 is connected with the bottom of the embedded steel plate support plate 5, the flat bottom of the shell 9 is connected with the top of the support plate 3, the second lifting assembly 7 is uniformly arranged with a plurality of second lifting assemblies 7, the upper support 13 of the second lifting assembly 7 is connected with the bottom of the movable end section 6, and the flat bottom of the shell 9 is connected with the top of the lower support 1; the precision of the gear 15 is 6-8.

[0035] When the height is adjusted, the high-precision gear 15 is rotated through the crank 10, the gear 15 is engaged with the rack 11, the rack 11 is driven to move up and down, when the gear 15 is rotated, the buckle 14 above the gear 15 is automatically lifted, when the rack 11 is lifted to the designed position, the gear 15 is clamped with the buckle 14, and when the rack 11 is slowly lowered, the buckle 14 is lifted.

[0036] When the post-tensioning method prefabricated prestressed small box girder is operated, the construction personnel measures the first lifting assembly 4 arranged on the support plate 3 through a slope ruler, a steel ruler and other measuring tools, so that the longitudinal slope and the transverse slope of the embedded steel plate at the beam end are precisely adjusted, after the adjustment is completed, the buckle 14 of the first lifting assembly 4 is clamped and fastened in place, the height, the transverse slope and the longitudinal slope of the embedded steel plate at the beam end are ensured to be not loosened and displaced during concrete pouring, and the longitudinal and transverse slope of the embedded steel plate at the beam end is precisely controlled.

[0037] Before the beam body is tensioned, the movable end section 6 is separately lowered by lowering the outer second lifting assembly 7 without moving the support plate 3 and the first lifting assembly 4, so that the bottom end of the beam body is not concentratedly stressed before tensioning, and the tensile stress cracking of the concrete at the bottom end of the beam body is avoided.

[0038] The technical features not described in the utility model can be realized by or using the prior art, and will not be described here again, of course, the above description is not a limitation of the utility model, and the utility model is not limited to the above examples, the changes, modifications, additions or replacements made by the ordinary skilled in the art within the essential scope of the utility model should also belong to the protection scope of the utility model.

Claims

1. A post-tensioned small box girder lifting platform, characterized in that, Including several lower supports (1), the lower support (1) is fixedly arranged on the ground, the top surface of the lower support (1) is provided with several embedded steel plate lower supports (2), and the top surface of the embedded steel plate lower support (2) is provided with a support plate (3); The support plate (3) is connected with the embedded steel plate support plate (5) through the first lifting assembly (4), and the top of the embedded steel plate support plate (5) is provided with an embedded steel plate; The lower support (1) is connected with the movable end section (6) through the second lifting assembly (7), and the top of the movable end section (6) is connected with the box girder formwork bottom plate (16).

2. The post-tensioned small box girder lifting platform according to claim 1, characterized in that, The lower support (1) is an I-shaped steel structure, and each group of the end section lower support (1) is provided with two symmetric and parallel ones.

3. The post-tensioned small box girder lifting platform according to claim 1, characterized in that, The embedded steel plate lower support (2) is a " " shaped structure, and is uniformly arranged on the top surface of the end section lower support (1) and arranged perpendicularly to the end section lower support (1); The embedded steel plate lower support (2) is located below the embedded hole of the box girder formwork bottom plate (16).

4. The post-tensioned small box girder lifting pad according to claim 1, characterized in that, The two sides of the box girder formwork bottom plate (16) are provided with movable end section reinforcing channel steels (18), and the inner sides of the movable end section reinforcing channel steels (18) are connected with the movable end section (6).

5. The post-tensioned small box girder lifting pad according to claim 1, characterized in that, The first lifting assembly (4) and the second lifting assembly (7) are the same in structure, and each comprises an upper support (13) at the top and a shell (9) at the bottom; The bottom of the shell (9) is flat, and a vertical rod body is arranged above the shell (9), one side of the rod body is rotatably connected with a gear (15) through a support, and a rack (11) is slidably connected to the top of the rod body; One side of the rod body, where the support is arranged, is provided with a square hole, and the square hole is in communication with the inside of the rod body; and the side, where the rack (11) is provided with teeth, is engaged with the gear (15) through the square hole. The gear (15) is coaxially and fixedly connected with a crank (10), and the crank is rotatably connected with the support.

6. The post-tensioned small box girder lifting bed as claimed in claim 5, characterized in that, The top of the shell (9) is hingedly connected with a buckle (14) through a hinge seat, the buckle (14) is in strip structure, and a protrusion is arranged at the bottom of the outer end of the buckle (14); and the protrusion is clamped in the teeth of the gear (15).

7. The post-tensioned small box girder lifting bed as claimed in claim 5, characterized in that, The top of the rack (11) is fixedly connected with a top bracket (12), the top bracket (12) is fixedly connected with the upper support (13), and the top surface of the upper support (13) and the flat bottom surface of the shell (9) are both pasted with anti-skid pads (8).

8. The post-tensioned small box girder lifting bed according to claim 7, characterized in that, The first lifting assembly (4) is uniformly arranged with a plurality of first lifting assemblies (4), the upper support (13) of the first lifting assembly (4) is connected with the bottom of the embedded steel plate support plate (5), and the flat bottom of the shell (9) is connected with the top of the support plate (3).

9. The post-tensioned small box girder lifting pad of claim 1, wherein, The second lifting assembly (7) is uniformly arranged with a plurality of second lifting assemblies (7), the upper support (13) of the second lifting assembly (7) is connected with the bottom of the movable end section (6), and the flat bottom of the shell (9) is connected with the top of the lower support (1).

10. The post-tensioned small box girder lifting bed as claimed in claim 5, wherein, The precision of the gear (15) is 6-8.

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