A precast beam middle diaphragm reserved structure

Abstract

The utility model discloses a kind of middle diaphragm reserved structures in precast beam, including precast beam side mould assembly, the precast beam side mould assembly including the adjustable exchange formwork unit being equipped in the middle part of the precast beam side mould, the cross section of the adjustable exchange formwork unit is the trapezoidal structure of upper wide lower narrow, its outside end width is 200mm, inside end width is 230mm, forming the gradual change section along the precast beam web direction, the inside edge top of the adjustable exchange formwork unit is equipped with stripping slope, and the slope range is 1 / 30-1 / 35, bottom is equipped with circular arc chamfer, radius is 25mm, the adjustable exchange formwork unit is fixedly connected with precast beam web, and the middle diaphragm precast part is formed by pouring through the adjustable exchange formwork unit, and the utility model can be recycled and be applicable to different angle precast beam by adjustable exchange formwork unit, formwork consumption reduces, and single set of formwork annual turnover times improves, and stripping time is shortened, and single piece middle diaphragm construction cycle is shortened, significantly speeds up precast beam production progress.

Description

Technical fields:

[0001] This utility model relates to the technical field of transverse diaphragms in precast beams, specifically to a pre-reserved structure for transverse diaphragms in precast beams. Background technology:

[0002] In the construction of precast beams, the mid-span transverse diaphragm is divided into precast and cast-in-place parts. The precast transverse diaphragm is the same width as the top slab of the precast beam. When the angle of the precast beam changes, the template of the transverse diaphragm with different angles needs to be changed to adapt to it. In the widening section of the bridge deck, the angle of each precast beam is different, and each precast beam requires a custom-made template, resulting in a large amount of template required for construction. After the precast beam is installed, because the transverse diaphragm is the same width as the precast beam and the extended part of the transverse diaphragm is relatively long, if the position of the precast beam is not precise enough during hoisting, the transverse diaphragms in the same span cannot be completely aligned, and the cast-in-place part in the same span will have a broken line problem, which will affect the appearance quality. Utility model content:

[0003] Therefore, this utility model provides a pre-reserved transverse diaphragm structure in a precast beam to overcome the problems of the prior art.

[0004] This utility model is implemented by the following technical solution:

[0005] A precast transverse diaphragm pre-reserved structure in a precast beam includes a precast beam side mold assembly. The precast beam side mold assembly includes an adjustable template unit in the middle of the precast beam side mold. The adjustable template unit has a trapezoidal cross-section that is wider at the top and narrower at the bottom. Its outer end width is 200mm and its inner end width is 230mm, forming a gradually changing cross-section along the web direction of the precast beam. The top of the inner edge of the adjustable template unit has a demolding slope with a slope range of 1 / 30–1 / 35, and the bottom has a rounded chamfer with a radius of 25mm. The adjustable template unit is fixedly connected to the web of the precast beam. The precast portion of the transverse diaphragm is cast and formed through the adjustable template unit, and it extends 50mm outward along the web direction of the precast beam.

[0006] Preferably, the replaceable template unit is replaced simultaneously on both sides during the prefabrication of the middle beam and adjusted on one side during the prefabrication of the side beam.

[0007] Preferably, the upper width of the adjustable template unit increases by 30mm to 260mm from the outer end (200mm) towards the inner side, while the lower part maintains a width of 200mm.

[0008] The advantages of this utility model are: the interchangeable template unit can be used for precast beams at different angles, the amount of template used is reduced, the annual turnover of a single template is increased, the demolding time is shortened, the construction cycle of a single transverse diaphragm is shortened, and the production progress of precast beams is significantly accelerated. Attached image description:

[0009] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic diagram of the structure described in this utility model;

[0011] Figure 2 This is a schematic diagram of the main structure of the present invention;

[0012] Figure 3 This is a top sectional view of the structure described in this utility model.

[0013] In the diagram: 1. Precast beam side formwork; 2. Adjustable template unit; 3. Precast beam web; 4. Draft angle; 5. Rounded chamfer. Detailed implementation method:

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0015] like Figure 1 , Figure 2 , Figure 3 As shown, a precast beam with a pre-reserved transverse diaphragm structure includes:

[0016] Installation of precast beam side formwork assembly

[0017] Adjustable template unit 2: Made of high-strength steel template, its cross-section is designed as a trapezoidal structure with a wider outer end and a narrower inner end, with a width of 200mm and a width of 230mm respectively. An installation groove matching the adjustable template unit 2 is opened in the middle of the precast beam side formwork 1. The adjustable template unit 2 is fixedly connected to the precast beam side formwork 1 with M20 high-strength bolts to ensure that the gap at the template splice is less than 2mm.

[0018] Precast beam web 3: During the production of precast beams, the interchangeable template unit 2 is installed flush with the outer side of the precast beam web 3, so that the precast part 3 of the middle transverse diaphragm extends outward by 50mm along the web direction, forming a gradually changing cross-section structure.

[0019] A 1 / 30 draft angle 4 is set at the top of the inner edge of the adjustable template unit 2 to ensure that the draft angle error does not exceed ±0.5°.

[0020] At the junction of the bottom of the replaceable template unit 2 and the precast beam web 311, a rounded chamfer 5 with a radius of 25mm is set. It is manufactured using an integrated mold forming process to avoid stress concentration that could lead to concrete cracking.

[0021] Forming of prefabricated part 3 of the middle transverse diaphragm

[0022] The reinforcing steel skeleton of the middle diaphragm is pre-tied within the replaceable formwork unit 2. The main reinforcement uses HRB400 grade steel bars with a diameter of 16mm and a spacing of 150mm. The outward-extending steel bars 12 extend 50mm beyond the formwork and lap with the subsequent cast-in-place reinforcement.

[0023] C50 high-performance concrete is used, with a slump controlled at 160-180mm. Layered vibration compaction is employed to ensure concrete density. After pouring, the concrete is cured to at least 80% of its design strength before formwork removal.

[0024] Precast beam construction

[0025] During the prefabrication of the central beam, the adjustable template units 2 on both sides are simultaneously installed to the middle of the prefabricated beam side formwork 1 and secured with bolts. At this point, the trapezoidal sections of the templates on both sides are arranged opposite each other, forming a complete prefabrication space for the central transverse diaphragm.

[0026] Concrete is poured, vibrated, and cured according to the conventional precast beam construction process. After the concrete reaches the demolding strength, the tie bolts are removed first, and then the replaceable formwork unit 2 is slowly pushed out along the demolding slope 4 using a jack. The bottom rounded chamfer 5 is used to reduce the frictional resistance between the formwork and the concrete, so as to achieve rapid demolding.

[0027] Precast edge beam construction

[0028] When prefabricating the side beams, the replaceable template unit 2 on one side is adjusted according to the cross slope of the bridge deck. For example, for the inner side beam, only the inner replaceable template unit 2 is replaced, while the outer template remains unchanged; for the outer side beam, the outer template is replaced. After adjustment, the trapezoidal section of the template matches the inclination angle of the side beam.

[0029] By adjusting the installation angle of the adjustable template unit 2, the upper side is widened by 30mm to 260mm, while the lower side remains 200mm wide, forming a gradual cross-section consistent with the cross slope of the side beam, ensuring that the central diaphragm is coordinated with the bridge deck line.

[0030] Precast beam installation and alignment

[0031] The prefabricated middle beams and side beams are hoisted to the bridge site for installation. Measurement and positioning are used to ensure that the reserved portions of the middle transverse diaphragms of adjacent prefabricated beams are precisely aligned, and the spacing error of the extended steel bars 12 is controlled within ±5mm.

[0032] Cast-in-place formwork erection

[0033] 15mm thick high-strength bamboo plywood is used, and it is supported on the outside of the extended section of the prefabricated part 3 of the middle transverse diaphragm. The height of the template is consistent with the design height of the middle transverse diaphragm.

[0034] Using M16 tie bolts spaced 500mm apart, pass them through the pre-drilled bolt holes on the web 3 of the precast beam to secure the bamboo plywood template to both sides of the extended section of the middle transverse diaphragm, ensuring that the template rigidity meets the requirements for concrete pouring.

[0035] Reinforcement connection and concrete pouring

[0036] The extended reinforcing bars of adjacent transverse diaphragms are connected by double-sided lap welding, and the weld length is not less than 5dd, which is the diameter of the reinforcing bar.

[0037] The diaphragm section was cast using C50 micro-expansion concrete. During casting, the process was carried out from one end to the other, and an immersion vibrator was used to compact the concrete to ensure a good bond between the new and old concrete.

[0038] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A precast beam diaphragm reserved structure, characterized in that, The precast beam side formwork assembly includes a precast beam side formwork (1) with an adjustable template unit (2) in the middle. The adjustable template unit (2) is fixed to the precast beam side formwork (1) by a detachable connection. The adjustable template unit (2) has a trapezoidal structure with a wider top and a narrower bottom. Its outer end width is 200mm and its inner end width is 230mm, forming a gradually changing cross section along the direction of the precast beam web (3). The top of the inner edge of the adjustable template unit (2) is provided with a demolding slope (4) with a slope range of 1 / 30–1 / 35. The bottom is provided with a rounded chamfer (5) with a radius of 25mm. The adjustable template unit (2) is fixedly connected to the precast beam web (3). The precast part of the middle transverse diaphragm is cast and formed by the adjustable template unit (2), and it extends outward by 50mm along the direction of the precast beam web (3).

2. The precast diaphragm reserved structure in a precast beam according to claim 1, characterized in that: The adjustable template unit (2) is replaced simultaneously on both sides when prefabricating the middle beam, and adjusted on one side when prefabricating the side beam.

3. The precast beam transverse diaphragm reserved structure according to claim 1, characterized in that, The detachable connection method uses high-strength bolts, and the performance grade of the high-strength bolts is 8.8 or above.

4. The precast beam transverse diaphragm reserved structure according to claim 1, characterized in that: The upper width of the adjustable template unit (2) increases by 30mm to 260mm from the outer end 200mm to the inner side, while the lower part maintains a width of 200mm.

Images