A local steel bar truss prestressed concrete composite bottom plate and its manufacturing method

Abstract

The present invention discloses a local steel bar truss prestressed concrete composite base plate and a manufacturing method thereof, comprising a prestressed concrete composite base plate and a local steel bar truss. The prestressed concrete composite base plate comprises a concrete plate and prestressed tendons embedded in the concrete plate in the longitudinal direction; the lower part of the local steel bar truss is embedded in the concrete plate, the upper part of the local steel bar truss is located outside the concrete plate, and the local steel bar truss is arranged in the longitudinal direction at the temporary support for construction in the mid-span of the prestressed concrete composite base plate. Compared with the prior art, the present invention resists the reverse bending moment caused by the support through the local steel bar truss, is simple to manufacture, and is flexible in application. While meeting the requirements of the span of the engineering application, the goal of construction without support or with less support is achieved, and the problem of high cost of composite floors caused by construction support and full-length steel bar truss arrangement at this stage is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of assembled concrete structures, and in particular to a local steel bar truss prestressed concrete composite bottom plate and a manufacturing method thereof. Background Art

[0002] In recent years, with the continuous advancement of the process of building industrialization, prefabricated concrete structures have developed rapidly, and precast concrete composite slabs have been widely used in prefabricated buildings, among which steel truss composite slabs (including steel tube truss composite slabs) are the most widely used. This product can reduce the wet work steps, construction formwork, and scaffolding usage during the construction process, while also reducing labor consumption, reducing construction difficulty, and improving construction efficiency. However, as far as the current situation is concerned, the cost of existing products is still high compared to cast-in-place slabs. The reason is that most of the cost of existing products is directly related to the cost of steel trusses (or steel tube trusses), and the cost of steel tube trusses is even higher than that of steel trusses.

[0003] The existing steel truss composite plate (or steel tube truss composite plate) is a prefabricated steel truss (or steel tube truss) arranged along the length direction of the concrete composite plate. The steel truss (or steel tube truss) is composed of an upper chord, a web and a lower chord, wherein the upper chord of the steel truss is made of steel bars, and the upper chord of the steel tube truss is made of steel pipes. When the precast concrete composite plate bottom plate is cast, the lower chord and part of the web of the steel truss (or steel tube truss) are buried in the precast concrete bottom plate, so that a steel truss composite plate (or steel tube truss composite plate) is formed. This kind of steel truss (or steel tube truss) contributes very little to the rigidity of the precast concrete composite bottom plate. The rigidity of the composite bottom plate is increased by adding concrete ribs to the bottom plate or increasing the thickness of the bottom plate. In addition, the manufacturing difficulty is relatively large, the cost is high, and the precision is difficult to control.

[0004] In terms of current applications, in order to meet the span requirements of engineering applications, reinforced truss composite slabs (or steel tube truss composite slabs) are generally constructed with supports, and the existence of construction supports also greatly increases the engineering cost of composite slabs. According to research and analysis, the cost of using one-way close-fitting prestressed concrete composite slabs can be greatly reduced. However, since prestressed concrete composite slabs do not have upper reinforced trusses or other forms of trusses, it is difficult to achieve no support or less support during the construction phase. If no support is used, its application span is limited and cannot meet the needs of engineering applications. If support is used, in order to ensure that the upper part of the prestressed concrete composite bottom plate is not torn, a lot of supports need to be set up to meet the force requirements of the construction phase, which will increase the cost.

[0005] Therefore, how to achieve the goal of no or less support for prestressed concrete composite slabs in the construction stage while meeting the span requirements of engineering applications, and solve the cost increase problem caused by multiple support settings and full-length arrangement of steel trusses (or steel tube trusses) is an urgent problem to be solved by technical personnel in this field. Summary of the invention

[0006] The purpose of the present invention is to provide a local steel truss prestressed concrete composite base plate and a manufacturing method thereof. During the construction stage, according to the requirements of the application span and the thickness of the composite base plate, 1 to 3 temporary supports are set at the mid-span position, and local steel trusses are arranged within a certain range at the support position to resist the reverse bending moment caused by the support.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] The invention discloses a local steel bar truss prestressed concrete composite bottom plate, comprising:

[0009] A prestressed concrete composite base plate, the prestressed concrete composite base plate comprising a concrete plate and prestressed tendons embedded in the concrete plate in the longitudinal direction;

[0010] A local steel truss, wherein the lower portion of the local steel truss is embedded in the concrete slab, the upper portion of the local steel truss is located outside the concrete slab, the local steel truss is longitudinally arranged at a temporary support constructed in the middle of the span of the prestressed concrete composite base plate, the length of the local steel truss covers the range of the reverse bending moment generated at the temporary support, and the length of the local steel truss is less than the longitudinal length of the prestressed concrete composite base plate.

[0011] Preferably, the prestressed concrete composite base plate is a smooth prestressed concrete composite base plate, and the upper surface of the smooth prestressed concrete composite base plate is a natural rough surface.

[0012] Preferably, the prestressed concrete composite base plate is a ribbed prestressed concrete composite base plate, and the upper surface of the ribbed prestressed concrete composite base plate is a ribbed surface.

[0013] Preferably, the local steel truss includes an upper chord, two webs and two lower chords, the upper chord and the lower chord are arranged longitudinally, one upper chord is located in the middle position of the upper side of the two lower chords, the two webs are respectively located on both sides of the upper chord, the lower parts of the two webs are respectively welded to one lower chord, and the upper parts of the two webs are welded to the same upper chord.

[0014] Preferably, the prestressed concrete composite base plate further comprises transverse reinforcement bars, which are pre-embedded in the concrete plate in a transverse direction and are located under the prestressed bars.

[0015] Preferably, the diameter of the prestressed tendons is 4.8 mm-16 mm.

[0016] Preferably, the thickness of the prestressed concrete composite base plate is not less than 30 mm.

[0017] Preferably, the upper chord bars and the lower chord bars are both hot-rolled ribbed steel bars with a diameter of 8 mm or 10 mm, and the web bars are cold-rolled smooth round steel bars with a diameter of 6 mm.

[0018] The present invention also discloses a method for manufacturing the above-mentioned local steel bar truss prestressed concrete composite bottom plate, comprising the following steps:

[0019] S1. Placing a plurality of prestressed tendons side by side in the longitudinal direction in a concrete mold or a mold platform;

[0020] S2. Use a steel bar tensioning machine to apply tension to both ends of each prestressed tendon. The tension applied to each prestressed tendon is 0.4 to 0.8 times its own tensile strength.

[0021] S3, placing a local steel truss longitudinally at a determined position in the concrete mold or mold base, the local steel truss including an upper chord, webs on both sides and a lower chord, so that the lower chord and the lower part of the web are located in the concrete mold or mold base, and the upper part of the web and the upper chord of the truss are located outside the concrete mold or mold base;

[0022] S4. Place transverse reinforcement into the concrete mold or mold base, and the transverse reinforcement is located under the prestressed reinforcement;

[0023] S5, pouring concrete into the concrete mold or formwork and completing curing, so that the prestressed concrete composite bottom plate and the local steel truss are combined to form a whole;

[0024] S6, cutting off the prestressed tendons at both ends of the prestressed concrete composite bottom plate;

[0025] S7. Use a lifting device to lift the prestressed concrete composite base plate together with the local steel bar truss out of the concrete mold or mold base to obtain the local steel bar truss prestressed concrete composite base plate.

[0026] Compared with the prior art, the present invention has achieved the following technical effects:

[0027] 1. Since the steel truss is only set at a local position of the temporary support for construction, the production is simplified, the operation is flexible, the product quality is easier to control, the workers on the construction site are easier to understand the role of the steel truss, and the construction quality is easier to control;

[0028] 2. The local steel frame truss is suitable for both smooth prestressed concrete composite slabs and ribbed prestressed concrete composite slabs. It is not restricted in the selection of prestressed concrete slabs and is flexible in application.

[0029] 3. It meets the span requirements of engineering applications, and at the same time achieves the goal of less support during the construction phase, reduces engineering costs, improves construction efficiency, and strengthens the positive guidance of one-way close-jointed composite floor slabs in prefabricated building applications;

[0030] 4. Due to the local arrangement of the steel truss, compared with the current steel truss composite plate (or steel tube truss composite plate), the amount of steel truss is greatly reduced, the cost is sharply reduced, and the economy is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 It is a top view of the local steel bar truss prestressed concrete composite bottom plate of this embodiment when a smooth prestressed concrete composite bottom plate is used;

[0033] Figure 2 This is a cross-sectional view of the local steel bar truss prestressed concrete composite bottom plate of this embodiment when a smooth prestressed concrete composite bottom plate is used;

[0034] Figure 3 It is a longitudinal section view of the local steel bar truss prestressed concrete composite bottom plate of this embodiment when a smooth prestressed concrete composite bottom plate is used;

[0035] Figure 4 It is a top view of the local steel bar truss prestressed concrete composite bottom plate of this embodiment when using a ribbed prestressed concrete composite bottom plate;

[0036] Figure 5 It is a cross-sectional view of the local steel bar truss prestressed concrete composite bottom plate of this embodiment when using a ribbed prestressed concrete composite bottom plate;

[0037] Figure 6 It is a longitudinal section view of the local reinforced steel truss prestressed concrete composite bottom plate of this embodiment when using a ribbed prestressed concrete composite bottom plate;

[0038] Explanation of the reference numerals: 1- smooth prestressed concrete composite base plate; 2- ribbed prestressed concrete composite base plate; 3- local steel truss; 4- upper chord; 5- web reinforcement; 6- lower chord; 7- upper surface; 8- prestressed tendons; 9- transverse reinforcement. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] The purpose of the present invention is to provide a local steel truss prestressed concrete composite base plate and a manufacturing method thereof. During the construction stage, according to the requirements of the application span and the thickness of the composite base plate, 1 to 3 temporary supports are set at the mid-span position, and local steel trusses are arranged within a certain range at the support position to resist the reverse bending moment caused by the support.

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] like Figure 1-6 As shown, this embodiment provides a local steel bar truss prestressed concrete composite bottom plate, including a prestressed concrete composite bottom plate and a local steel bar truss 3.

[0043] The prestressed concrete composite base plate includes a concrete plate and prestressed tendons 8 embedded in the concrete plate in the longitudinal direction; the lower part of the local steel truss 3 is embedded in the concrete plate, and the upper part of the local steel truss 3 is located outside the concrete plate. The local steel truss 3 is arranged in the longitudinal direction at the temporary support for the mid-span construction of the prestressed concrete composite base plate, and the length of the local steel truss 3 covers the range of the reverse bending moment generated at the temporary support, and the length of the local steel truss 3 is less than the longitudinal length of the prestressed concrete composite base plate.

[0044] The existence of the local steel truss 3 can effectively resist the reverse bending moment at and around the construction support position, solving the problem of cracking of the upper part of the precast concrete floor when a small amount of temporary support is set during the construction phase. At the same time, due to the existence of the local steel truss 3, 1 to 3 temporary supports can be set horizontally in the middle of the floor span during the construction phase, solving the problem of limited span caused by the composite floor bearing capacity not meeting the requirements.

[0045] In this embodiment, the prestressed concrete composite base plate can be a smooth prestressed concrete composite base plate 1 (such as Figure 1-3As shown), the upper surface 7 of the smooth prestressed concrete composite bottom plate 1 is a naturally rough surface; the prestressed concrete composite bottom plate can also be a ribbed prestressed concrete composite bottom plate 2 (as shown Figure 4-6 As shown), the upper surface 7 of the ribbed prestressed concrete composite base plate 2 is a ribbed surface.

[0046] There are many specific forms of the local steel truss 3. In this embodiment, the local steel truss 3 includes an upper chord 4, two webs 5 and two lower chords 6. The upper chord 4 and the lower chord 6 are arranged longitudinally, and an upper chord 4 is located in the middle of the upper side of the two lower chords 6, and the two webs 5 are located on both sides of the upper chord 4. The lower parts of the two webs 5 are respectively welded to a lower chord 6, and the upper parts of the two webs 5 are welded to the same upper chord 4. Since the local steel truss 3 is supported in a triangular shape as a whole, the bearing capacity is relatively strong.

[0047] In order to further improve the bearing capacity, the prestressed concrete composite base plate of this embodiment also includes transverse steel bars 9, which are pre-buried in the concrete plate in the transverse direction and are located under the prestressed bars 8.

[0048] In this embodiment, the diameter of the prestressed tendon 8 is preferably 4.8mm-16mm; the thickness of the prestressed concrete composite base plate is preferably not less than 30mm; the upper chord tendons 4 and the lower chord tendons 6 are preferably hot-rolled ribbed steel bars with a diameter of 8mm or 10mm, and the web tendons 5 are preferably cold-rolled smooth round steel bars with a diameter of 6mm.

[0049] This embodiment also provides a method for manufacturing the above-mentioned local steel bar truss prestressed concrete composite bottom plate, comprising the following steps:

[0050] S1, placing a plurality of prestressed tendons 8 side by side in the longitudinal direction in a concrete mold or a mold base;

[0051] S2. Use a steel bar tensioning machine to apply tension to both ends of each prestressed tendon 8. The tension value applied to each prestressed tendon 8 is 0.4 to 0.8 times its own tensile strength;

[0052] S3, placing a local steel truss 3 longitudinally at a determined position in the concrete mold or the mold platform, the local steel truss 3 including an upper chord 4, webs 5 on both sides and a lower chord 6, so that the lower chord 6 and the lower part of the webs 5 are located in the concrete mold or the mold platform, and the upper part of the webs 5 and the upper chord 4 of the truss are located outside the concrete mold or the mold platform;

[0053] S4, placing transverse reinforcement 9 in the concrete mold or mold platform, the transverse reinforcement 9 is located under the prestressed reinforcement 8;

[0054] S5, pouring concrete into the concrete mold or mold base and completing the curing, so that the prestressed concrete composite bottom plate and the local steel truss 3 are combined to form a whole;

[0055] S6, cutting off the prestressed tendons 8 at both ends of the prestressed concrete composite bottom plate;

[0056] S7. Use a lifting device to lift the prestressed concrete composite bottom plate together with the local steel bar truss 3 out of the concrete mold or the mold base, so as to obtain the local steel bar truss prestressed concrete composite bottom plate.

[0057] The present specification uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A local steel truss prestressed concrete composite floor, It is characterized in that include: A prestressed concrete composite base plate, the prestressed concrete composite base plate comprising a concrete plate and prestressed tendons embedded in the concrete plate in the longitudinal direction; A local steel truss, wherein the lower part of the local steel truss is pre-buried in the concrete slab, the upper part of the local steel truss is located outside the concrete slab, the local steel truss is longitudinally arranged at a temporary support for mid-span construction of the prestressed concrete composite bottom slab, the length of the local steel truss covers the range of the reverse bending moment generated at the temporary support, and the length of the local steel truss is less than the longitudinal length of the prestressed concrete composite bottom slab; The local steel bar truss includes an upper chord, two web bars and two lower chords. The upper chord and the lower chord are arranged longitudinally. One upper chord is located in the middle position of the upper side of the two lower chords. The two web bars are respectively located on both sides of the upper chord. The lower parts of the two web bars are respectively welded to one lower chord, and the upper parts of the two web bars are welded to the same upper chord.

2. The local steel bar truss prestressed concrete composite floor according to claim 1, It is characterized in that The prestressed concrete composite base plate is a smooth prestressed concrete composite base plate, and the upper surface of the smooth prestressed concrete composite base plate is a natural rough surface.

3. The local steel bar truss prestressed concrete composite floor according to claim 1, It is characterized in that The prestressed concrete composite bottom plate is a ribbed prestressed concrete composite bottom plate, and the upper surface of the ribbed prestressed concrete composite bottom plate is a ribbed surface.

4. The local steel bar truss prestressed concrete composite floor according to claim 1, It is characterized in that The prestressed concrete composite bottom plate also includes transverse steel bars, which are pre-embedded in the concrete plate in a transverse direction and are located under the prestressed steel bars.

5. The local steel bar truss prestressed concrete composite floor according to claim 1, It is characterized in that The diameter of the prestressed tendons is 4.8 mm to 16 mm.

6. The local steel bar truss prestressed concrete composite floor according to claim 1, It is characterized in that The thickness of the prestressed concrete composite base plate is not less than 30 mm.

7. The local steel bar truss prestressed concrete composite floor according to claim 1, It is characterized in that The upper chord bars and the lower chord bars are both hot-rolled ribbed steel bars with a diameter of 8 mm or 10 mm, and the web bars are cold-rolled smooth round steel bars with a diameter of 6 mm.

8. A method for manufacturing a local steel bar truss prestressed concrete composite floor according to any one of claims 1 to 7, It is characterized in that The steps include: S1. Placing a plurality of prestressed tendons side by side in the longitudinal direction in a concrete mold or a mold base; S2. Use a steel bar tensioning machine to apply tension to both ends of each prestressed tendon. The tension applied to each prestressed tendon is 0.4 to 0.8 times its own tensile strength. S3. Place a local steel bar truss longitudinally at a determined position in the concrete mold or formwork. The local steel bar truss includes upper chord bars, web bars on both sides, and lower chord bars, such that the lower chord bars and the lower parts of the web bars are inside the concrete mold or formwork, and the upper parts of the web bars and the upper chord bars of the truss are outside the concrete mold or formwork; S4. Place transverse steel bars inside the concrete mold or formwork. The transverse steel bars are located below the prestressing tendons; S5. Pour concrete into the concrete mold or formwork and complete curing, so that the prestressed concrete composite floor slab and the local steel bar truss are combined into a whole; S6. Cut off the prestressing tendons at both ends of the prestressed concrete composite floor slab; S7. Use a lifting device to lift the prestressed concrete composite floor slab and the local steel bar truss together out of the concrete mold or formwork, thus obtaining a local steel bar truss prestressed concrete composite floor slab.

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