High-durability string truss structure

Abstract

The invention discloses a high-durability string truss structure. The high-durability string truss structure comprises an upright quadrangular pyramid truss; the invention discloses an external prestress basalt fiber reinforced composite inhaul cable. The supporting rod is shared by the orthogonal prestress inhaul cables, and the surface of the steel structure is coated with the high-toughness concrete. The periphery of the net rack is supported on the steel columns. The tops of the supporting rods are connected with the net rack through bolt balls, and the bottoms of the supporting rods are connected with the prestressed inhaul cables through cast steel cable clamps. And the end part of the inhaul cable is connected with the support through an anchorage device. And the outer surface of the steel skeleton is coated with a layer of high-toughness concrete of which the thickness is not more than 10mm. The structural form provided by the invention is simple and attractive, and meanwhile, the stability and the safety of the structure can be greatly improved; the structure allowable span is large, so that the number of stand columns and foundations is reduced, the construction cost is reduced, and the construction speed is increased; the steel framework and the prestressed basalt fiber reinforced composite inhaul cable are coated with the high-toughness concrete, so that the durability of the structure is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of structural engineering, and in particular to a highly durable string-tensioned grid structure. Background Art

[0002] Traditional photovoltaic brackets are usually made of steel, which has the characteristics of simple structure, convenient installation and high rigidity. However, in practical applications, traditional photovoltaic brackets face challenges such as large amount of structural steel, large number of foundations and difficult construction. Especially in extreme weather conditions, their stability is poor, which may cause damage to photovoltaic modules. These shortcomings limit the construction and development of photovoltaic brackets. In order to solve this problem, grid structures were introduced. This type of structural system has a high bearing capacity, large span, strong stability and easy construction. However, in the marine environment, high salinity and humid climate will accelerate the corrosion of steel structures. Therefore, the durability of grid structures has become an urgent problem to be solved in engineering.

[0003] In order to solve the above problems, anti-corrosion coatings such as epoxy resin, polyurethane coating or zinc coating are usually applied to the surface of steel structures; alloy steels with better corrosion resistance, such as stainless steel or weathering steel, can also be used to improve the corrosion resistance of the structure. However, the existing grid structure still faces some challenges: First, the frequent occurrence of extreme weather such as strong winds and typhoons in coastal environments has put forward higher requirements for the stability and safety of grid structures; second, the use of alloy steels with better corrosion resistance will significantly increase material costs, resulting in large initial investments; finally, in order to prevent or slow down corrosion, grid structures need to be regularly coated with anti-corrosion coatings, which makes the subsequent operation and maintenance costs higher. Summary of the invention

[0004] In order to cope with the challenges faced by traditional photovoltaic support structures, the present invention proposes a highly durable tensioned grid structure.

[0005] A highly durable tensioned grid structure, comprising:

[0006] Place the tetrahedral grid upright;

[0007] Pulling cables at both ends of the upright tetrahedral pyramid grid;

[0008] A support rod disposed between the upright tetrahedral pyramid grid and the cables;

[0009] High-toughness concrete poured on the upright tetrahedral pyramid grid and the support rods;

[0010] The cable is made of basalt fiber reinforced composite material;

[0011] The high-toughness concrete refers to a concrete with an ultimate tensile strain of 3%-8%, and a corresponding crack width of less than or equal to 0.1 mm when the ultimate tensile strain is reached.

[0012] In the present invention, the outer surface of the grid is coated with high-toughness concrete, which plays a role in protecting the structural steel skeleton. In the cable-stayed grid structure system proposed by the present invention, the high-toughness concrete can ensure that no or only small cracks are generated under load, thereby improving the durability of the structure; the prestressed basalt fiber reinforced composite cable outside the body uses the retraction of the cable to apply prestress to the structure, thereby achieving the purpose of limiting deformation, cracks and improving bearing capacity. Among them, the basalt fiber reinforced composite material has the advantages of good high temperature resistance, strong UV resistance, low moisture absorption rate, etc., thus greatly reducing the material cost and improving the durability of the structure.

[0013] The following is a preferred technical solution of the present invention:

[0014] The highly durable tensioned grid structure adopts an upright quadrangular pyramid grid and is supported on steel columns at the periphery.

[0015] The highly durable tensioned lattice structure is composed of an upper chord, a lower chord, a web, a strut and a prestressed cable.

[0016] The high-durability tensioned grid rods are all connected by bolt balls, and the orthogonal prestressed cables share a common support rod.

[0017] The top of the support rod and the grid are connected by a bolt ball, and the bottom of the support rod and the prestressed cable are connected by a cast steel cable clamp.

[0018] The upright tetrahedral grid is made by connecting round steel pipes with bolts and balls. The support rods are vertically fixed at the node positions of the upright tetrahedral grid.

[0019] The prestressed cable is made of basalt fiber reinforced composite material, and the end portion is connected to the support through an anchor.

[0020] The upper chord, lower chord, web and support rod are all round steel pipes.

[0021] In the highly durable tensioned grid structure, high-toughness concrete is coated on the steel frame of the tensioned grid; the thickness of the high-toughness concrete layer does not exceed 10 mm, which plays a role in protecting the steel frame.

[0022] The high-toughness concrete is wrapped around the round steel tube of the upright tetrahedral grid. The thickness of the high-toughness concrete wrapped around the round steel tube of the upright tetrahedral grid is 5 to 10 mm. The support rod is a round steel tube, and the high-toughness concrete is wrapped around the round steel tube. The thickness of the high-toughness concrete wrapped around the round steel tube of the support rod is 5 to 10 mm.

[0023] The basalt fiber reinforced composite material is made of basalt fiber and polyurethane through a pultrusion process, wherein the weight content of basalt fiber accounts for 75% to 85%, and the weight content of polyurethane accounts for 15% to 25%.

[0024] The highly durable string-type grid structure proposed by the present invention has the following advantages:

[0025] (1) The cable-stayed grid structure is simple and beautiful, and greatly improves the stability and safety of the structure.

[0026] (2) The cable-stayed grid structure allows for a large span, thereby reducing the number of columns and foundations, reducing construction costs and speeding up construction.

[0027] (3) The high-toughness concrete covering the steel skeleton does not produce or produces multiple densely distributed fine cracks under the action of tensile stress, which can effectively isolate the steel from the external environment and prevent the steel from rusting, thereby significantly improving the durability of the tensioned grid structure and greatly reducing the operation and maintenance costs.

[0028] (4) Prestressed cables are made of basalt fiber reinforced composite materials, which is a green inorganic fiber material with a material strength of more than 1300MPa. Prestressed basalt fiber reinforced composite cables have good high temperature resistance, strong UV resistance, low moisture absorption rate, good durability, and greatly reduce the subsequent operation and maintenance costs.

[0029] (5) Compared with the existing grid structure, the structural form proposed by the present invention is simple and beautiful, and can greatly improve the stability and safety of the structure; the structure allows a large span, thereby reducing the number of columns and foundations, reducing construction costs and speeding up construction; at the same time, by using high-toughness concrete to cover the steel frame and prestressed basalt fiber reinforced composite cables, the durability of the structure is effectively improved and the operation and maintenance costs are reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is an axonometric diagram of a string-grid structure;

[0031] Figure 2 It is a cross-section diagram of the string grid structure;

[0032] Figure 3 It is a cross-section diagram of the string grid structure;

[0033] Figure 4 It is a schematic diagram of the connection of the struts of the string grid structure;

[0034] Figure 5 Schematic diagram of the end connection of the prestressed cables of the tensioned grid structure. DETAILED DESCRIPTION

[0035] The following describes in detail the implementation of the highly durable string-type grid structure of the present invention in conjunction with the accompanying drawings.

[0036] like Figure 1 As shown in Figures 2 and 3, a highly durable tensioned grid structure comprises the following components: an upright tetrahedral grid 1, an externally prestressed basalt fiber reinforced composite cable 2, a strut 3, and a high-toughness concrete 4.

[0037] like Figure 2 As shown, the upright tetrahedral pyramid grid 1 is composed of an upper chord 1 - 1 , a lower chord 1 - 2 , and a web 1 - 3 , and the upright tetrahedral pyramid grid 1 is supported on peripheral steel columns 5 .

[0038] like Figure 1 As shown in FIG. 2 , by tensioning the prestressed basalt fiber reinforced composite cable 2 , the orthogonal tetrahedral pyramid grid 1 has sufficient rigidity and bearing capacity. The orthogonal prestressed basalt fiber reinforced composite cable 2 shares the support rod 3 .

[0039] like Figure 3 As shown, a layer of high-toughness concrete 4 with a thickness not exceeding 10 mm is coated outside the steel skeleton to block or slow down the corrosion of the steel skeleton and improve the durability of the structure.

[0040] like Figure 4 As shown, the top of the support rod 3 is connected to the upright tetrahedral grid 1 through a bolt ball 6, and the bottom of the support rod 3 is connected to the cast steel cable clamp 7 by welding, and the prestressed basalt fiber reinforced composite cable 2 passes through the cast steel cable clamp 7.

[0041] like Figure 5 As shown, the end of the prestressed basalt fiber reinforced composite cable 2 is connected to the grid support 9 through an anchor 8.

[0042] The basalt fiber reinforced composite material used in the present invention is made of basalt fiber and polyurethane through a pultrusion molding process. The elastic modulus of the basalt fiber is 95-115GPa, the tensile strength is 3300-4500MPa, and the ultimate elongation is 2.4-3.0%. The basalt fiber (manufacturer is Shanxi Jintou Basalt Development Co., Ltd., the specification is 13 microns of polyurethane system) content accounts for 80% in the basalt fiber reinforced composite material, and the polyurethane (manufacturer is Nanjing Jufa New Materials Co., Ltd., the specification is 2221P) content accounts for 20%. The performance test of the basalt fiber reinforced composite material obtained under this ratio shows that its tensile strength is 1200MPa, the elastic modulus is 50GPa, and the ultimate elongation is 2.2%.

[0043] The high-toughness concrete used in the present invention comprises cement, active mineral admixture, aggregate, fiber and water, wherein the active mineral admixture comprises fly ash, silica fume, granulated blast furnace slag and metakaolin, the maximum particle size of the aggregate does not exceed 0.5 mm, the fiber adopts one or a combination of polyvinyl alcohol fiber, polyethylene fiber and aromatic polyamide fiber, the fiber length is 5 mm to 25 mm, the diameter is 0.015 mm to 0.055 mm, the elastic modulus is 30 GPa to 150 GPa, the tensile strength is 1000 MPa to 3500 MPa, the ultimate elongation is 2% to 15%, and the weight ratio of each component of cement and active mineral admixture is:

[0044]

[0045] Performance tests on high-toughness concrete obtained under the above mix ratio show that its ultimate tensile strain can reach 3.2% (about 320 times that of ordinary concrete), and the corresponding crack width at the ultimate tensile strain is 0.049mm; the flexural strength is 12.8MPa (about twice that of ordinary concrete), the uniaxial compressive strength is 48MPa, and the compressive strain corresponding to the peak load is 0.55% (about twice that of ordinary concrete).

Claims

1. A highly durable string-type grid structure, characterized in that: include: Place the tetrahedral grid upright; Pulling cables at both ends of the upright tetrahedral pyramid grid; A support rod disposed between the upright tetrahedral pyramid grid and the cables; High-toughness concrete poured on the upright tetrahedral pyramid grid and the support rods; The cable is made of basalt fiber reinforced composite material; The high-toughness concrete refers to a concrete with an ultimate tensile strain of 3%-8%, and a corresponding crack width of less than or equal to 0.1 mm when the ultimate tensile strain is reached.

2. The highly durable tensioned grid structure according to claim 1, characterized in that: The support rods are vertically fixed at the node positions of the upright tetrahedral pyramid grid.

3. The highly durable tensioned grid structure according to claim 1, characterized in that: The upright tetrahedral grid is made by connecting round steel pipes with bolts and balls.

4. The highly durable tensioned grid structure according to claim 3, characterized in that: The high-toughness concrete is wrapped around the round steel pipe of the upright tetrahedral grid.

5. The highly durable tensioned grid structure according to claim 4, characterized in that: The thickness of the high-toughness concrete wrapped on the round steel pipe of the upright tetrahedral grid is 5 to 10 mm.

6. The highly durable tensioned grid structure according to claim 1, characterized in that: The support rod is a round steel pipe, and the high-toughness concrete is wrapped around the round steel pipe.

7. The highly durable tensioned grid structure according to claim 6, characterized in that: The thickness of the high-toughness concrete wrapped around the round steel pipe of the support rod is 5 to 10 mm.

8. The highly durable tensioned grid structure according to claim 1, characterized in that: The basalt fiber reinforced composite material is made of basalt fiber and polyurethane through a pultrusion process, wherein the weight content of basalt fiber accounts for 75% to 85%, and the weight content of polyurethane accounts for 15% to 25%.

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