Large-span cantilever triangular truss

Abstract

The large-span cantilever triangular truss comprises a first main beam, a second main beam and a secondary beam, one end of the first main beam is perpendicularly welded to one end of the second main beam, the other end of the first main beam is connected with the other end of the second main beam through the secondary beam, and three welding connection points are arranged on the second main beam at intervals. The welding connection points are opposite to the positions of three continuous layers of pre-embedded steel plates of the main body structure, and the second main beam is vertically installed along the main body structure and is welded and fixed to the pre-embedded steel plates through the welding connection points; five web members are arranged among the first main beam, the second main beam and the secondary beam; according to the large-span cantilever triangular truss, the problems that a traditional truss is insufficient in rigidity, low in bearing capacity and large in lateral deformation are solved through combined application of the structural steel of different specifications, three-dimensional force transmission design of multi-floor connecting points and optimization of the number and layout of the web members.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of building construction technology, especially relate to a large span cantilever triangular truss. BACKGROUND

[0002] At present, the construction industry is booming, and many high-rise buildings and even super high-rise buildings are driven by unique design concepts to build multi-layer super long cantilever structures in the air. Such multi-layer large cantilever structures require strict requirements for the cantilever length and bearing capacity of the lower construction platform. For large cantilever structure construction, the current conventional measures are to install trusses at the lower floors of large cantilever structures to build working platforms for large cantilever structure construction. However, in the multi-layer large cantilever structure construction scene, since the cantilever structure concrete strength cannot bear the load when it is less than 100%, when the load of multi-layer cantilever structure and its support and protection system is superimposed, the traditional cantilever truss mostly uses single specification section steel (such as I-beam or channel steel), which has insufficient overall stiffness and bearing capacity, and it is difficult to meet the load superposition requirements of multi-layer large cantilever structure. In addition, the connection mode of the traditional truss is mostly single-layer fixed, with limited bearing capacity, and lacks optimization design of slenderness ratio, resulting in large lateral deformation, affecting construction safety and structural stability, so it is difficult to meet the safety construction standard, and the safety protection coefficient is low. CONTENT OF THE UTILITY MODEL

[0003] The utility model aims at providing a large-span cantilever triangular truss with large stiffness, small deformation and high bearing capacity after connecting with the main structure, which solves the problems of insufficient stiffness, low bearing capacity and large lateral deformation of traditional trusses through the combination application of different specification section steels, the three-dimensional force transmission design of multi-floor connection points and the optimization of the number and layout of web members.

[0004] The technical solution of the utility model is a large-span cantilever triangular truss, which comprises a first main beam, a second main beam and a secondary beam. One end of the first main beam is perpendicular to one end of the second main beam and is welded together. The other end of the first main beam is connected to the other end of the second main beam through the secondary beam. Three welded connection points are arranged on the second main beam at intervals. The welded connection points are opposite to the positions of the pre-buried steel plates pre-buried in three layers of the main structure. The second main beam is installed vertically along the main structure and is welded and fixed to the pre-buried steel plates through the welded connection points, forming a three-dimensional force transmission network.

[0005] The first main beam, the second main beam and the secondary beam are provided with five web members, wherein one end of the first web member is vertically welded at the middle point of the secondary beam, and the other end is welded at the joint of the first main beam and the second main beam; one end of the second web member is vertically welded at the middle point of the first main beam, and the other end is welded at the joint of the first web member and the secondary beam; one end of the third web member is vertically welded at the middle point of the second main beam, and the other end is welded at the joint of the first web member and the secondary beam; one end of the fourth web member is vertically welded on the secondary beam, and the other end is welded at the joint of the second web member and the first main beam; one end of the fifth web member is vertically welded on the secondary beam, and the other end is welded at the joint of the third web member and the second main beam.

[0006] As preferred, the joints of the first main beam, the second main beam, the secondary beam and the five web members are welded with 20mm-thick stiffening plates.

[0007] As preferred, the first main beam is a HW344*348*10*16 steel with a length of about 7.7m; the second main beam is a HW344*348*10*16 steel with a length of about 8.1m; and the secondary beam is a HW250*250*9*14 steel with a length of about 10m.

[0008] As preferred, the web members are HW250*250*9*14 steels, the length of the web members is 2.3m-5m, and the slenderness ratio of the members is λ≤80.

[0009] Compared with the prior art, the utility model has the advantages of:

[0010] (1) The second main beam of the triangular truss is welded and fixed with the pre-buried steel plates of the three continuous layers of the main structure to form a three-dimensional force transmission network of "main beam-secondary beam-three layers of main structure", the load is transmitted to the secondary beam through the main beam, the secondary beam disperses the load to the frame columns and shear walls of the three layers of main structure through three layers of welding points, the load transmission is more reliable and efficient, the load borne by the triangular truss is transmitted to the three layers of main structure, the stress concentration caused by single-layer connection is avoided, and the triangular truss has greater bearing capacity due to multi-point force compared with the single-layer connection system.

[0011] (2) The five web members are arranged in the triangular truss, the slenderness ratio of the members is controlled to be λ≤80, the stability of the members is ensured, the overall rigidity of the triangular truss is improved, and the lateral deformation is effectively reduced compared with the structure without web members.

[0012] (3) The HW344 main beam, the HW250 secondary beam and the web members are combined, the large-section main beam is matched with the small-section secondary beam and the web members to form a rigidity gradient distribution system, the overall bending resistance of the triangular truss is optimized, the overall bending rigidity is improved by 45% after combination, the ultimate bearing capacity of a single truss reaches 300kN, and the synchronous construction load of the three layers and above of the cantilever structure can be covered.

[0013] ⑷By setting 20mm thick stiffened plate at the intersection of the first main beam, the second main beam, the secondary beam and the web, the stress concentration coefficient of the node area is reduced to below 1.2, which is significantly optimized compared with the traditional node stress. The web is arranged at the connecting point of the truss and the embedded part, the force transmission of the node of the truss is utilized, the stress concentration is avoided, the node stiffness is increased, the stress is more reasonable, and the stress concentration damage of the connecting point is avoided.

[0014] ⑸The triangular truss can be directly lifted and welded after being welded and assembled on the ground, and the construction is more convenient and efficient. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a structural schematic view of the large-span cantilever triangular truss of the utility model;

[0016] Figure 2 is a stiffened plate arrangement schematic view of the large-span cantilever triangular truss of the utility model.

[0017] MAIN COMPONENT SYMBOL DESCRIPTION:

[0018] The first main beam 1, the second main beam 2, the welded connecting point 21, the secondary beam 3, the web 4, the first web 41, the second web 42, the third web 43, the fourth web 44, the fifth web 45, the main body structure 5, the embedded steel plate 51 and the stiffened plate 6. DETAILED DESCRIPTION

[0019] The utility model will be further described in detail below in combination with the drawings:

[0020] Please refer to Figure 1 The utility model provides a kind of large-span cantilever triangular truss, including first main beam 1, second main beam 2 and secondary beam 3, one end of first main beam 1 and one end of second main beam 2 are perpendicular to each other and are welded, form right-angle main body frame;The other end of first main beam 1 is connected with the other end of second main beam 2 by secondary beam 3, to form right-angle triangular frame. Figure 1As shown, three welding connecting points 21 are arranged on the second main beam 2 at intervals, and the welding connecting points 21 are opposite to the positions of the three layers of embedded steel plates 51 embedded continuously in the main body structure 5, the second main beam 2 is installed vertically along the main body structure 5 and is welded and fixed with the embedded steel plates 51 through the welding connecting points 21, thereby forming a three-dimensional force transmission network. The large-span cantilever triangular truss provided by the utility model connects the triangular truss and the main body structure through the welding mode, is more firm compared with the traditional bolt anchoring mode, and the three layers of embedded steel plates of the triangular truss and the main body structure are welded, thereby forming a three-dimensional force transmission network of "main beam -> secondary beam -> three layers of main body structure", the load is transmitted to the secondary beam through the main beam, the secondary beam disperses the load to the main body structure frame column and the shear wall through the three layers of welding points, the force transmission is more reliable and efficient, the load borne by the triangular truss is transmitted to the three layers of main body structure, stress concentration caused by single-layer connection is avoided, compared with the single-layer connection system, multi-point stress makes the triangular truss have greater bearing capacity, the synchronous construction demand of the three layers and above high-altitude cantilever structure can be met, and the construction safety and the structure quality are well guaranteed.

[0021] Please refer to Figure 1 As shown, five web members 4 are arranged between the first main beam 1, the second main beam 2 and the secondary beam 3, wherein one end of the first web member 41 is welded perpendicularly at the middle point of the secondary beam 3, and the other end of the first web member 41 is welded at the joint of the first main beam 1 and the second main beam 2; one end of the second web member 42 is welded perpendicularly at the middle point of the first main beam 1, and the other end of the second web member 42 is welded at the joint of the first web member 41 and the secondary beam 3; one end of the third web member 43 is welded perpendicularly at the middle point of the second main beam 2, and the other end of the third web member 43 is welded at the joint of the first web member 41 and the secondary beam 3; one end of the fourth web member 44 is welded perpendicularly on the secondary beam 3, and the other end of the fourth web member 44 is welded at the joint of the second web member 42 and the first main beam 1; one end of the fifth web member 45 is welded perpendicularly on the secondary beam 3, and the other end of the fifth web member 45 is welded at the joint of the third web member 43 and the second main beam 2. By arranging five web members in the triangular truss, the stability of the rod member is ensured, the overall stiffness of the triangular truss is improved, and the lateral deformation is effectively reduced compared with the structure without web members.

[0022] Please refer to Figure 2 As shown, the joints of the first main beam 1, the second main beam 2, the secondary beam 3 and the five web members 4 are all welded with the 20mm-thick stiffening plates 6. Finite element analysis shows that the stress concentration coefficient of the node area is reduced to below 1.2, which is significantly optimized compared with the traditional node stress; the stiffening plates 6 are additionally arranged at each connecting point, thereby further avoiding stress concentration, the stress is more reasonable, and the node stiffness and overall stability are improved.

[0023] In the embodiment, the first main beam 1 is a HW344*348*10*16 type steel, the length of the first main beam 1 is about 7.7 m; the second main beam 2 is a HW344*348*10*16 type steel, the length of the second main beam 2 is about 8.1 m; the secondary beam 3 is a HW250*250*9*14 type steel, the length of the secondary beam 3 is about 10 m; the web member 4 is a HW250*250*9*14 type steel, the length of the web member 4 is 2.3-5 m, by arranging five web members inside the triangular truss, according to the formula λ=L / r (L is the calculated length of the rod, and r is the cross-section rotation radius), the slenderness ratio of the rod of the web member 4 is controlled to λ≤80, the overall stiffness of the triangular truss is improved, and the lateral deformation is reduced by 30% compared with the structure without the web member through finite element simulation verification.

[0024] It is worth noting that, since the length of the first main beam 1 of the triangular truss of the utility model reaches 7.7 m, the cantilever is super-long, and the length of the secondary beam 3 reaches 10 m, the three-layer main body structure is connected, the span is very large, and the secondary beam is prone to form a weak stress point, therefore, by adopting the combination of the HW344 type main beam and the HW250 type secondary beam and the web member, the matching of the large-section main beam and the small-section secondary beam and the five web members forms a stiffness gradient distribution system; the main beam and the secondary beam are matched by different specifications of H-shaped steel, the overall bending resistance of the triangular truss is optimized, the bending inertia moment of the main beam is 2.3 times that of the secondary beam, the overall bending stiffness is improved by 45% after combination through finite element simulation verification, and the ultimate bearing capacity of a single truss reaches 300 kN, which can cover the synchronous construction load of the three-layer and above cantilever structure; the main beam and the secondary beam are butt welded and a stiffener plate is welded at the joint to reinforce, the welding seam is grade one, and local stress concentration caused by stiffness difference is avoided.

[0025] The large-span cantilever triangular truss provided by the utility model realizes significant improvement in stiffness, bearing capacity, stability and construction efficiency through differentiated steel combination, web member layout optimization, multi-layer force transmission design, node stress control and synchronous construction adaptability, the technical scheme comprehensively solves the load superposition problem in the construction of the multi-layer large cantilever structure, the triangular truss can be integrally hoisted after ground welding, supports the synchronous construction of the three-layer and above cantilever structure in combination with the multi-layer connection point design, and breaks through the limitations of the traditional single-layer support system.

[0026] The above only describes the preferred embodiments of the utility model, and any changes and modifications made within the scope of the utility model claims shall fall within the scope of the utility model claims.

Claims

1. A large-span cantilevered triangular truss, characterized in that, It includes a first main beam, a second main beam, and a secondary beam. One end of the first main beam and one end of the second main beam are welded perpendicularly to each other. The other end of the first main beam is connected to the other end of the second main beam through the secondary beam. The second main beam is provided with three welding connection points at intervals. The welding connection points are opposite to the positions of the pre-embedded steel plates that are embedded in three consecutive layers of the main structure. The second main beam is installed vertically along the main structure and is fixed to the pre-embedded steel plates by welding through the welding connection points to form a three-dimensional force transmission network. Five web members are provided between the first main beam, the second main beam, and the secondary beam. The first web member has one end vertically welded to the midpoint of the secondary beam, and the other end welded to the junction of the first and second main beams. The second web member has one end vertically welded to the midpoint of the first main beam, and the other end welded to the junction of the first web member and the secondary beam. The third web member has one end vertically welded to the midpoint of the second main beam, and the other end welded to the junction of the first web member and the secondary beam. The fourth web member has one end vertically welded to the secondary beam, and the other end welded to the junction of the second web member and the first main beam. The fifth web member has one end vertically welded to the secondary beam, and the other end welded to the junction of the third web member and the second main beam.

2. The large-span cantilevered triangular truss according to claim 1, characterized in that, The first main beam, the second main beam, the secondary beam, and the five web members are all welded with 20mm thick stiffening plates.

3. The large-span cantilevered triangular truss according to claim 1 or 2, characterized in that, The first main beam is made of HW344*348*10*16 steel and has a length of approximately 7.7m; the second main beam is made of HW344*348*10*16 steel and has a length of approximately 8.1m; the secondary beam is made of HW250*250*9*14 steel and has a length of approximately 10m.

4. The large-span cantilevered triangular truss according to claim 3, characterized in that, The web members are made of HW250*250*9*14 steel, with a length of 2.3m-5m and a slenderness ratio λ≤80.

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