Background
The template is used as an important tool in the construction of a cast-in-place concrete structure, and the technical performance of the template directly influences the quality and the cost of construction engineering and the economic benefit of enterprises. According to statistics, in the construction of cast-in-place concrete structure, every 1m2The concrete engineering template has the use amount of 4-5 m2The construction cost accounts for 30-35% of the construction cost of the cast-in-place concrete structure, the labor consumption accounts for 40-50%, and the construction period accounts for about 50%. The template engineering occupies more expense cost and construction period, and is an important factor influencing the engineering construction progress, the construction cost and the engineering construction quality.
The steel-concrete composite beam is a new type of beam developed on the basis of steel structure and concrete structure, and its rib portion is made up by using steel beam, wing plate is made up by using concrete slab, and the two are connected into one body by using shear-resisting connecting piece or perforated steel plate. The two materials are combined together in the form of a composite beam, so that respective defects can be avoided, the advantages of the two materials are fully exerted, and a structural form with high strength, high rigidity and good ductility is formed. Compared with a concrete beam, the steel-concrete combined beam has the advantages of light weight, large bearing capacity, strong spanning capacity and the like; compared with steel plate beams, the steel-concrete composite beam saves steel by about 20-40%, and can reduce the manufacturing cost. However, the main defects of the common steel-concrete composite beam with the exposed section steel are that the steel is easily rusted and the fireproof performance is inferior to that of the reinforced concrete due to the exposed steel.
The fabric Reinforced Concrete (TRC) is a new composite material formed from high-performance fine aggregate Concrete and multiaxial alkali-resisting fibre net (such as carbon fibre, alkali-resisting glass fibre and basalt fibre), and possesses the advantages of good bearing capacity, crack-resisting capacity, thin wall, light weight, high strength, corrosion resistance and strong plasticity, etc., and can be used for light prefabricated component and structure reinforcement field.
Disclosure of Invention
The technical problem to be solved is as follows: the application provides a novel TRC permanent formwork steel-concrete composite beam and a preparation method thereof, aiming at reducing the engineering consumption of a formwork, improving the construction efficiency, overcoming the problems that a steel-concrete composite beam is easy to rust and poor in fireproof performance and improving the durability of the structure. The TRC thin plate is used as a U-shaped permanent template, a box-shaped steel beam is arranged on the lower half part of a U-shaped cavity of the U-shaped permanent template to form the U-shaped TRC combined permanent template, and the height of the box-shaped steel beam is half of that of the combined beam. And placing a steel reinforcement framework in a compression area in the U-shaped cavity at the upper half part of the U-shaped TRC combined permanent template, and pouring concrete to form the TRC combined permanent template steel-concrete combined beam.
The technical scheme is as follows:
a novel TRC permanent formwork steel-concrete composite beam is composed of high-performance fine aggregate concrete, a fabric net fixed by a stainless steel plate net lining, a box-shaped steel beam, a steel bar framework, cast-in-place concrete, side die cavities, upper die cavities, protruding ribs, outer side plates, inner side plates and inner transverse plates, wherein the inner side plates and the outer side plates are respectively provided with two blocks which are arranged in parallel, the two inner side plates are arranged between the two outer side plates, the bottoms of the two inner side plates are connected with the bottoms of the two outer side plates, the tops of the two inner side plates are connected through the inner transverse plates, the side die cavities are formed between the inner side plates and the outer side plates, the upper die cavities are formed between the inner transverse plates and the outer side plates, the protruding ribs are arranged on the side surfaces of the die cavities of the inner side plates, the box-shaped steel beam is arranged on the inner transverse plates, the fabric net fixed by the stainless steel plate net lining is arranged in the side die cavities and the, the high-performance fine aggregate concrete is poured into the side die cavity and the upper die cavity except the box-shaped steel beam, the steel bar framework is placed on the box-shaped steel beam, and the cast-in-place concrete is arranged in a U-shaped cavity formed by the high-performance fine aggregate concrete and the box-shaped steel beam.
In a preferred embodiment of the present invention, the height of the inner side plate of the side cavity is half of the designed beam height.
As a preferable technical scheme of the invention, the height of the box-shaped steel beam is half of the designed beam height.
As a preferable technical scheme of the invention, each side edge of the box-shaped steel beam exceeds the inner side plate by 1-2 cm.
In a preferred embodiment of the present invention, the outer surface of the box-shaped steel beam is provided with pattern-like protrusions.
As a preferable technical scheme of the invention, the fabric net fixed by the stainless steel plate net lining consists of a U-shaped stainless steel plate net and a fabric net.
A preparation method of a novel TRC permanent formwork steel-concrete composite beam comprises the following steps:
firstly, manufacturing a U-shaped TRC combined permanent template: manufacturing an inverted concave template for pouring the U-shaped TRC combined permanent template according to the beam design; inverting the concave template to form an inverted concave shape; the die cavity of the inverted concave die plate consists of two wing side die cavities and an upper die cavity, the two wing side die cavities correspond to TRC die plates on two sides of the U-shaped TRC combined permanent die plate, the upper die cavity corresponds to a bottom TRC transverse die plate and a box-shaped steel beam of the U-shaped TRC combined permanent die plate, each side die cavity consists of an inner side plate and an outer side plate, and the upper die cavity consists of an inner transverse plate and an outer side plate of the side die cavity; the height of the inner side plate of the side die cavity is half of the designed beam height, and the side surface of the die cavity of the inner side plate is provided with a raised fillet for forming inner grooves of the die plates on two sides of the U-shaped TRC combined permanent die plate;
the second step is that: placing the box-shaped steel beam on the center of the internal transverse plate, and clamping the box-shaped steel beam and the internal transverse plate at two ends of the steel beam by using a carpenter clamp; the height of the box-shaped steel beam is half of the designed beam height, and each side edge of the steel beam exceeds the inner side plate by 1-2 cm; the box-shaped steel beam is made by rolling or welding pattern steel plates, and pattern-like bulges are distributed on the outer surface of the box-shaped steel beam;
the third step: cutting a multi-axis alkali-resistant fabric net and a stainless steel plate net according to the design size of the beam, rolling the cut stainless steel plate net into a U-shaped net lining, and binding the fabric net on the surface of the stainless steel plate net lining by using fine iron wires to tightly fix the fabric net and the stainless steel plate net lining together; when binding the fabric net, straightening the fabric net simultaneously, and keeping the straightened state in the binding process to form the fabric net fixed by the stainless steel plate net lining;
the fourth step: placing the fabric net fixed by the stainless steel plate net lining into the two wing side die cavities and the upper die cavity of the inverted concave die plate;
the fifth step: pouring high-performance fine aggregate concrete from the opening at the upper part of the inverted concave template and vibrating;
and a sixth step: after the maintenance is finished, the inverted concave template is removed to form a U-shaped TRC combined permanent template; the common mixing proportion of the high-performance fine aggregate concrete in the TRC is as follows: cement (C), sand (S), water (W), an additional water reducing agent (JM-PCA (I)) =1:1.4:0.32: 0.015; the cement is 52.5 ordinary portland cement; the sand used for the test is medium sand with fineness modulus of 2.6 II and apparent density of 1.2g/cm3(ii) a The added water reducing agent is JM-PCA (I) type superplasticizer;
the seventh step: placing the bound reinforcement cage into a U-shaped cavity of a U-shaped TRC combined permanent template, placing the reinforcement cage on the box-shaped steel beam, and enabling the distance between the reinforcement cage and the TRC templates on two sides to be equal;
eighth step, pouring concrete in the U-shaped cavity in situ: and filling the mixed cast-in-place concrete into the U-shaped cavity of the whole TRC permanent formwork, then trowelling the surface of the concrete, and curing the concrete to a specified age to finish the preparation of the TRC permanent formwork steel-concrete composite beam.
Has the advantages that: compared with the prior art, the novel TRC permanent formwork steel-concrete composite beam and the preparation method thereof adopt the technical scheme, and have the following technical effects:
1. because the TRC has the advantages of light weight, high strength, crack resistance, corrosion resistance and the like, the TRC can be made to be very thin and is particularly suitable for being used as a permanent template;
2. on one hand, the TRC has light dead weight and is convenient for construction; on the other hand, the TRC can bear an external load during construction;
3. compared with the fabric net hardened by dipping, the stainless steel plate net is adopted for fixing, so that the method is simple and feasible, the rigidity and the anti-impact shearing capability of the TRC template can be improved, and overlarge deformation or damage in the transportation and construction processes can be avoided.
8. The lower half part of the U-shaped TRC combined permanent template is a hollow box-shaped steel beam, so that the weight of the beam can be obviously reduced, and the tensile force of a tensile area of the beam can be borne;
4. the tension area is mainly formed by steel beams, and the compression area is formed by steel-concrete combined beams of cast-in-place concrete at the upper part;
5. the TRC at the lower part not only plays a role of a template, but also can be used as a part of a structure to bear partial tension of a tension area and improve the bearing capacity of the composite beam;
6. the raised pattern on the outer surface of the steel beam needs to meet certain height requirements, so that the bonding and meshing effect of the steel beam, cast-in-place concrete and fine aggregate concrete is effectively increased. In addition, grooves are formed in the inner sides of the templates on the two sides of the TRC combined permanent template, so that cast-in-place concrete and fine aggregate concrete are better bonded together;
7. according to the TRC permanent formwork steel-concrete combined beam, the TRC formwork is used as a permanent formwork at the stage of upper concrete cast-in-place, and no additional formwork is needed, so that the construction process of formwork support and formwork removal of a cast-in-place reinforced concrete structure is simplified, the construction efficiency is improved, the engineering cost is reduced, and the construction time is shortened; the lower part of the steel-concrete combined beam is a hollow box-shaped steel beam, so that materials are saved, the weight of the beam is smaller, and the tensile property of steel and the compressive property of concrete can be fully utilized; the compact TRC template is arranged outside the box-shaped steel beam for protection, the chlorine ion permeation resistance and the water permeation resistance of the TRC template are far superior to those of common concrete, the corrosion of the steel beam can be effectively prevented, the fire resistance of the steel-concrete composite beam can be enhanced, and the durability of the structure is improved.
Detailed Description
Example 1:
a novel TRC permanent formwork steel-concrete composite beam is composed of high-performance fine aggregate concrete 1, a fabric net 2 fixed by a stainless steel plate net lining, a box-shaped steel beam 3, a steel bar framework 4, cast-in-place concrete 5, a side mold cavity 6, an upper mold cavity 7, protruding ribs 8, outer side plates 9, inner side plates 10 and inner transverse plates 11, wherein the inner side plates 10 and the outer side plates 9 are respectively provided with two blocks, the inner side plates 10 and the outer side plates 9 are arranged in parallel, the two inner side plates 10 are arranged between the two outer side plates 9, the bottoms of the two inner side plates 10 are connected with the bottoms of the two outer side plates 9, the tops of the two inner side plates 10 are connected through the inner transverse plates 11, the side mold cavity 6 is formed between the inner side plates 10 and the outer side plates 9, the upper mold cavity 7 is formed between the inner transverse plates 11 and the outer side plates 9, the side surfaces of the mold cavity of the inner side plates 10 are provided with the protruding ribs, the box-shaped steel beam 3 is arranged on an inner transverse plate 11, the fabric net 2 fixed by the stainless steel plate net lining is arranged in a side die cavity 6 and an upper die cavity 7, the high-performance fine aggregate concrete 1 is poured in the side die cavity 6 and the upper die cavity 7 except the box-shaped steel beam 3, the steel reinforcement framework 4 is placed on the box-shaped steel beam 3, and the cast-in-place concrete 5 is arranged in a U-shaped cavity formed by the high-performance fine aggregate concrete 1 and the box-shaped steel beam 3.
The preparation method of the novel TRC permanent formwork steel-concrete composite beam comprises the following steps:
firstly, manufacturing a U-shaped TRC combined permanent template: manufacturing an inverted concave template for pouring the U-shaped TRC combined permanent template according to the beam design; inverting the concave template to form an inverted concave shape; the die cavity of the inverted concave template consists of two-wing side die cavities 6 and an upper die cavity 7, the two-wing side die cavities 6 correspond to TRC templates on two sides of the U-shaped TRC combined permanent template, the upper die cavity 7 corresponds to a bottom TRC transverse template and a box-shaped steel beam 3 of the U-shaped TRC combined permanent template, each side die cavity 6 consists of an inner side plate 10 and an outer side plate 9, and the upper die cavity 7 consists of an inner transverse plate 11 and the outer side plates 9 of the side die cavities 6; the height of an inner side plate 10 of the side die cavity 6 is half of the designed beam height, and a raised fillet 8 is arranged on the side surface of the die cavity of the inner side plate 10 and used for forming inner grooves of the die plates on two sides of the U-shaped TRC combined permanent die plate;
the second step is that: placing the box-shaped steel beam 3 on the center of the inner transverse plate 11, and clamping the box-shaped steel beam and the inner transverse plate at two ends of the steel beam by using carpenter clamps; the height of the box-shaped steel beam 3 is half of the designed beam height, and each side edge of the steel beam exceeds the inner side plate by 1-2 cm; the box-shaped steel beam 3 is made by rolling or welding pattern steel plates, and pattern bulges are distributed on the outer surface of the box-shaped steel beam 3;
the third step: cutting a multi-axis alkali-resistant fabric net and a stainless steel plate net according to the design size of the beam, rolling the cut stainless steel plate net into a U-shaped net lining, and binding the fabric net on the surface of the stainless steel plate net lining by using fine iron wires to tightly fix the fabric net and the stainless steel plate net lining together; when binding the fabric net, straightening the fabric net simultaneously, and keeping the straightened state in the binding process to form the fabric net 2 fixed by the stainless steel plate net lining;
the fourth step: placing the fabric net 2 fixed by the stainless steel plate net lining into the two-wing side mold cavity 6 and the upper mold cavity 7 of the inverted concave mold plate;
the fifth step: pouring and vibrating high-performance fine aggregate concrete 1 from an opening at the upper part of the inverted concave template;
and a sixth step: after the maintenance is finished, the inverted concave template is removed to form a U-shaped TRC combined permanent template; the common mixing proportion of the high-performance fine aggregate concrete in the TRC is as follows: cement (C), sand (S), water (W), an additional water reducing agent (JM-PCA (I)) =1:1.4:0.32: 0.015; the cement is 52.5 ordinary portland cement; the sand used for the test is medium sand with fineness modulus of 2.6 II and apparent density of 1.2g/cm3(ii) a The added water reducing agent is JM-PCA (I) type superplasticizer;
the seventh step: placing the bound reinforcement cage 4 into a U-shaped cavity of the U-shaped TRC combined permanent template, and placing the reinforcement cage 4 on the box-shaped steel beam 3 with equal distance from TRC templates on two sides;
eighthly, casting concrete 5 in the U-shaped cavity in situ: and filling the mixed cast-in-place concrete 5 into the U-shaped cavity of the whole TRC permanent formwork, then trowelling the surface of the concrete, and curing the concrete to a specified age to finish the preparation of the TRC permanent formwork steel-concrete composite beam.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the present invention, and any modifications, equivalents, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.