Construction method for super-large-area seamless prestressed concrete terrace

Abstract

The invention discloses a construction method for an ultra-large-area seamless prestressed concrete terrace, which comprises the following steps of: S1, excavating a foundation layer to an original soil design elevation, and constructing a foundation layer cement macadam stable layer on the foundation layer; s2, a PE damp-proof film is laid on the base cement macadam stable layer; s3, a sand slippage layer is laid, and a PE damp-proof slippage film is laid on the sand slippage layer; s4, integral seamless concrete slab construction is carried out; and S5, finally, a flexible polyurethane carving-resistant section layer is constructed on the seamless concrete slab so as to provide surface protection and attractive effects. According to the construction method for the ultra-large-area seamless prestressed concrete terrace, the common problems of cracking, insufficient flatness, limited bearing capacity and the like in large-area terrace construction are effectively solved by introducing a prestress technology and a seamless design concept; and meanwhile, for floor construction of a shielding area, specific measures are taken to meet special insulation and grounding requirements.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, and in particular to a construction method for a super-large-area seamless prestressed concrete floor. Background Art

[0002] Flooring refers to the use of specific materials and processes to construct the original ground and present a certain decorative and functional ground. With the rapid advancement of urbanization and the continuous innovation of construction technology, the construction requirements of ultra-large-area floors are increasing, especially in industrial plants, transportation hubs and large public buildings that have extremely high requirements for flatness, bearing capacity and durability.

[0003] In the prior art, the floor length of some large factories is relatively long, and the thickness of the floor concrete is generally about 200-300mm. The floor structure is easily cracked under the shrinkage stress of the concrete itself and the external load during normal use, which greatly affects the service life of the floor. In order to alleviate this cracking phenomenon, the current method of laying the floor in sections and adding ordinary steel mesh is adopted, so that it is necessary to make cutting seams on the floor, which affects the use and appearance of the floor. In some special usage scenarios, such as special floor construction involving shielded areas, it is also necessary to add a shielding layer structure to the floor hierarchy. Therefore, how to better integrate the shielding layer construction into the existing floor construction is also one of the issues that technical personnel in this field need to consider. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a construction method for ultra-large area seamless prestressed concrete floors. By introducing prestressed technology and seamless design concepts, the common problems of cracking, insufficient flatness and limited bearing capacity in large-area floor construction are effectively solved; at the same time, for the floor construction in the shielded area, targeted measures are taken to meet special insulation and grounding requirements.

[0005] The invention provides a construction method for a large-area seamless prestressed concrete floor, which is characterized by comprising the following steps:

[0006] S1. Excavate the base layer to the original soil design elevation, and construct a cement gravel stabilization layer on the base layer;

[0007] S2. Lay PE moisture-proof membrane on the base cement gravel stabilization layer;

[0008] S3. Then the sand slip layer is laid, and a PE moisture-proof slip film is laid on the sand slip layer;

[0009] S4. Carry out the construction of integral seamless concrete slab;

[0010] S5. Finally, a flexible polyurethane anti-cutting surface layer is constructed on the seamless concrete slab to provide surface protection and aesthetic effect.

[0011] Further, in step S4, the construction of the integral seamless concrete slab includes the following steps: formwork production and installation → wall column foot protection construction, fixing anchors and explosion-proof steel bars → sequentially laying out steel strands, corrugated pipes and grounding system welding → corner structural steel bar construction → concrete pouring and its leveling and compaction and finishing maintenance → prestressing → grouting and anchor sealing.

[0012] Furthermore, it also includes the construction of a shielding layer structure arranged between step S2 and step S3, and includes the following steps: first constructing a concrete cushion layer on the PE moisture-proof membrane in step S2, then constructing a shielding layer on the concrete cushion layer, and finally arranging a concrete shielding protective layer on the shielding layer.

[0013] Furthermore, in step S3, the PE moisture-proof membrane laid on the sand sliding layer has a two-layer structure.

[0014] Furthermore, in step S4, post-tensioned bonded liquid-solid reinforcement and a floor double anchor free plate anchor system are used to ensure the stability of the structure.

[0015] Furthermore, in the construction of the integral seamless concrete slab, the prestressing is respectively initial tensioning and final tensioning, the initial tensioning is used to apply 25% of the prestress, and the concrete strength is greater than 30MPa during the final tensioning.

[0016] Furthermore, in the construction of the integral seamless concrete slab, when standard anchors cannot be arranged at both ends of the prestressed tendons, standard tensioning end anchors and steel bar structures arranged at the anchoring ends are used for tensioning coordination.

[0017] Furthermore, the steel bar structure of the anchor end includes a prestressed tendon and an anchor end steel strand bundle arranged at the end of the prestressed tendon located inside the concrete, the anchor end steel strand bundle is composed of a plurality of steel strands and forms the steel strand bundle into a broom-shaped overall structure, and the steel strand is provided with an anchoring portion at the end away from the prestressed tendon; and also includes stirrups sleeved on the outside of the anchor end steel strand bundle.

[0018] The present invention has the following beneficial effects:

[0019] (1) The present invention uses pre-embedded prestressed steel strands and grouting pipes before concrete pouring, and gradually applies prestress to the pre-embedded steel strands after concrete pouring to control cracks caused by early concrete shrinkage. After tensioning, grouting is performed to seal the entire process, thereby improving the strength of the concrete structure by means of prestressing and reducing the cost of later maintenance.

[0020] (2) The present invention organically combines prestressed technology and seamless design, so that the floor can still maintain excellent flatness and durability under heavy loads and complex environmental conditions; and in special areas with shielding requirements, customized stirrups, bellows and other materials are used, combined with grounding, shielding and other process measures to ensure that the floor meets special usage requirements, further improving the overall performance and safety of the floor system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0022] Figure 1 It is a construction flow chart of the ultra-large area seamless prestressed concrete floor in the present invention;

[0023] Figure 2 It is a structural layer diagram of the ultra-large area seamless prestressed concrete floor in the present invention;

[0024] Figure 3 It is a structural schematic diagram of the steel bar structure of the anchor end in the present invention;

[0025] Explanation of the reference numerals: 1-base layer; 2-cement gravel stabilization layer; 3-PE moisture-proof membrane; 4-concrete cushion layer; 5-shielding layer; 6-concrete shielding protection layer; 7-sand sliding layer; 8-PE moisture-proof sliding membrane; 9-integral seamless concrete slab; 10-flexible polyurethane anti-cutting surface layer; 11-concrete; 12-corrugated pipe; 13-steel strand; 14-anchoring part; 15-hoops; 16-connecting steel bars. DETAILED DESCRIPTION

[0026] As shown in the figure, the present invention provides a construction method for a large-area seamless prestressed concrete floor, comprising the following steps:

[0027] S1. Excavate the foundation 1 to the original soil design elevation, and construct the base cement gravel stabilization layer 2 on the foundation 1; the foundation 1 is processed with specific reference to the structural drawing to ensure the bearing capacity and stability of the foundation, and the base cement gravel stabilization layer 2 is set to 350mm thick, mainly based on the local slope of the floor deepening design drawing to enhance the stability of the foundation 1;

[0028] S2. Laying a PE moisture-proof membrane 3 on the cement gravel stabilization layer 2; wherein the PE moisture-proof membrane 3 is set to 0.5mm thick, only one layer is laid, mainly for moisture-proofing;

[0029] S3. Then, a sand sliding layer 7 is laid, and a PE moisture-proof sliding film 8 is laid on the sand sliding layer 7; wherein the thickness of the sand sliding layer 7 is 30 mm, and using the sand layer as the sliding layer helps to reduce interlayer friction and improve the flexibility of the overall structure; the PE moisture-proof sliding film 8 is set to be 0.3 mm thick, mainly used for moisture-proof and has a sliding function, and two layers are laid to enhance the effect;

[0030] S4. Construction of the integral seamless concrete slab 9; the integral seamless concrete slab 9 is 350mm thick and is specially made of C40 concrete. It adopts post-tensioned adhesive liquid-solid reinforcement and floor double anchor free slab anchor system to ensure the stability of the structure;

[0031] S5. Finally, a flexible polyurethane anti-cutting surface layer 10 is constructed on the seamless concrete slab 9 to provide surface protection and aesthetic effects; the flexible polyurethane anti-cutting surface layer 10 is set to be 5mm thick and is formed by polyurethane resin ground + glass fiber mesh cloth three cloths and four oils, mainly used to provide surface protection and aesthetic effects.

[0032] In this embodiment, in step S4, the construction of the integral seamless concrete slab 9 includes the following steps: formwork production and installation → wall column foot protection construction, fixing anchors and explosion-proof steel bars → sequentially laying out steel strands, corrugated pipes and grounding system welding → corner structural steel bar construction → concrete pouring and its leveling and compaction finishing maintenance → prestressing tensioning → grouting and anchor sealing; combined with Figure 1As shown, when laying the steel strand, the steel strand is rolled and placed in a steel strand pay-off drum, and the steel strand is manually dragged and dropped. After measuring the length of the material, the steel strand is cut with a grinding wheel cutter. After the laying of the steel strand and ordinary steel bars is completed, attention should be paid to fixing the steel strand to ensure that it will not be moved during concrete pouring; and when laying and installing the corrugated pipe 12, attention should be paid to the fact that the corrugated pipe 12 will not be damaged by the concrete vibrator; when fixing and installing the anchor seat and explosion-proof steel bars, the anchor seat must be firmly fixed and in the correct direction, and it must be ensured that the joints of the corrugated pipe 12 and the anchor plate are in the same straight line and must not be There are no inflection points; when grouting the pipeline and sealing the anchor, all prestressed tendons that have completed the tensioning process must be grouted as soon as possible, mainly injected from one end of the pipeline until the slurry in the pipeline is full and there are no bubbles remaining, and the cement slurry flows out from the slurry outlet end and the consistency is basically the same as that of the grouting end. When the grouting material solidifies, the excess grouting pipe is cut off and the anchor position is sealed with cement slurry until it is flush; for the compaction, leveling and finishing of the concrete slab, the slurry is mainly raised with a support-type trowel during the initial setting period; then a scraper is used for leveling; a driving trowel is used for finishing; and a scraper is used again for finishing. Use a ruler to level; use a driving trowel to repeat the above steps until finishing; and proper maintenance is the main process to reduce / eliminate surface cracking, mainly using multiple flexible maintenance. After finishing, first wet with water, then cover with a water-retaining film to ensure that the surface layer has enough moisture for hydration reaction, so that the surface layer will not sand, dust, or crack; when installing the floor edge formwork, set the formwork according to the design elevation, use a level to check the formwork elevation at any time, use a wedge-shaped wooden block to adjust the deviation, and set a triangular diagonal brace at a spacing of 1-1.5m on the outside of the formwork to make the formwork The slab is straight and stable. Before pouring concrete, the bottom gap is sealed with cement mortar to prevent concrete leakage. Finally, angle steel or force-transmitting steel bar pins are set at all expansion joints. The column foot, wall foot and embedded parts are treated to ensure that the wall panels, column foot, door opening edge, tunnel and pipe are separated from the floor with isolation blocks, compression materials (extruded boards) or isolation agents to prevent shrinkage and deformation. The columns and walls also need to be protected. The corners also need to be reinforced to strengthen the key parts of the floor structure and ensure the stability and safety of the overall structure.

[0033] In this embodiment, the shielding layer structure construction is also included between step S2 and step S3, and includes the following steps: first constructing a concrete cushion layer on the PE moisture-proof membrane in step S2, then constructing a shielding layer on the concrete cushion layer, and finally arranging a concrete shielding protective layer on the shielding layer; combining Figure 2 As shown, the concrete cushion layer 4 uses 100mm thick C20 fine stone concrete, which is leveled by laser with a flatness of ≤5mm / 2m and a slurry finish to ensure a smooth and beautiful surface; the shielding layer 5 uses a shielding layer constructed by a professional manufacturer; the concrete shielding protection layer uses an 80mm thick shielding layer composed of C25 concrete, which is mainly designed and constructed by a professional manufacturer to provide additional protection.

[0034] In this embodiment, during the construction of the integral seamless concrete slab 9, the prestressing is performed as initial tensioning and final tensioning respectively. The initial tensioning is used to apply 25% prestress, and the concrete strength is greater than 30MPa during the final tensioning. The initial tensioning is arranged after the concrete is poured, and the first tensioning is performed. About 15 hours after the concrete pouring is completed, the formwork is removed, the embedded plastic box is taken out, the anchor ring and the clip are installed, and 25% prestress is applied to control the shrinkage cracks of the early concrete. When the concrete strength reaches 30MPa, all the remaining prestress is tensioned as soon as possible. Each group of prestressed cables is composed of four groups of steel strands, and jacks are used to tension them one by one in sequence.

[0035] In this embodiment, during the construction of the integral seamless concrete slab 9, when standard anchors cannot be arranged at both ends of the prestressed tendons, standard tensioning end anchors and steel bar structures arranged at the anchoring ends are used for tensioning cooperation; the steel bar structure at the anchoring end includes prestressed tendons and anchoring end steel strand bundles arranged at the inner end of the prestressed tendons located at the concrete 1, the anchoring end steel strand bundle is composed of a plurality of steel strands 3 and forms the steel strand bundle into a broom-shaped integral structure, the steel strand 3 is provided with an anchoring portion 4 at the end away from the prestressed tendons; the prestressed tendons include a corrugated tube 2 and a middle section steel strand bundle arranged in the corrugated tube 2; one end of the steel strand 3 is connected to the prestressed tendons, and the other end is bent outward along the center line of the prestressed tendons; wherein the prestressed tendons The force reinforcement is composed of a steel strand bundle and a corrugated tube 2 sleeved on the outside of the steel strand bundle, and the steel strand bundle is composed of multiple steel strands 3, and the steel strand 3 is formed by multiple steel bars spirally wound together; the anchor end steel strand bundle is formed by the middle section of the steel strand bundle extending from the corrugated tube 2. In order to disperse the stress of the anchor end and fully integrate it with the concrete 1 of the anchor end to facilitate the tensioning of the tensioning end, the steel strands 3 in the anchor end steel strand bundle are bent outward to eventually form a broom-shaped overall structure; in order to strengthen the anchoring force of the anchor end, an anchoring portion 4 is also provided at the end of the steel strand 3 away from the prestressed tendon; by arranging stirrups 5 on the outside of the anchor end steel strand bundle, the concrete strength of the anchor end can be effectively strengthened and the concrete at the anchor end can be prevented from cracking.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A construction method for ultra-large area seamless prestressed concrete floor, characterized by: The following steps are involved: S1. Excavate the foundation to the original soil design elevation, and construct a base cement gravel stabilization layer on the foundation; S2. Lay PE moisture-proof membrane on the base cement gravel stabilization layer; S3. Then the sand slip layer is laid, and a PE moisture-proof slip film is laid on the sand slip layer; S4. Carry out the construction of integral seamless concrete slab; S5. Finally, a flexible polyurethane anti-cutting surface layer is constructed on the seamless concrete slab to provide surface protection and aesthetic effect.

2. The construction method for ultra-large area seamless prestressed concrete floor according to claim 1 is characterized in that: In step S4, the integral seamless concrete slab construction includes the following steps: Formwork production and installation → Construction of wall column foot protection, fixing anchors and explosion-proof steel bars → Laying out steel strands, corrugated pipes and grounding system welding in sequence → Construction of structural steel bars at corners → Concrete pouring and its leveling, compaction and finishing maintenance → Prestressing → Grouting and anchor sealing.

3. The construction method for ultra-large area seamless prestressed concrete floor according to claim 1 is characterized in that: It also includes the construction of a shielding layer structure arranged between step S2 and step S3, and includes the following steps: first constructing a concrete cushion layer on the PE moisture-proof membrane in step S2, then constructing a shielding layer on the concrete cushion layer, and finally arranging a concrete shielding protective layer on the shielding layer.

4. The construction method for ultra-large area seamless prestressed concrete floor according to claim 1 is characterized in that: In step S3, the PE moisture-proof membrane laid on the sand sliding layer has a two-layer structure.

5. The construction method for ultra-large area seamless prestressed concrete floor according to claim 2 is characterized in that: In step S4, post-tensioned bonded liquid-solid reinforcement and a double-anchor free plate anchor system for the floor are used to ensure the stability of the structure.

6. The construction method for ultra-large area seamless prestressed concrete floor according to claim 2 is characterized in that: In the construction of the integral seamless concrete slab, the prestressing is divided into initial tensioning and final tensioning. The initial tensioning is used to apply 25% of the prestress, and the concrete strength is greater than 30MPa during the final tensioning.

7. The construction method for ultra-large area seamless prestressed concrete floor according to claim 2 is characterized in that: In the construction of integral seamless concrete slabs, when standard anchors cannot be arranged at both ends of the prestressed tendons, standard tensioning end anchors and steel bar structures arranged at the anchoring ends are used for tensioning coordination.

8. The construction method for ultra-large area seamless prestressed concrete floor according to claim 7 is characterized in that: The steel bar structure of the anchor end includes a prestressed tendon and an anchor end steel strand bundle arranged at the end of the prestressed tendon located inside the concrete. The anchor end steel strand bundle is composed of a plurality of steel strands and forms a broom-shaped integral structure of the steel strand bundle. The steel strand is provided with an anchoring portion at the end away from the prestressed tendon; and also includes stirrups sleeved on the outside of the anchor end steel strand bundle.

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