Curved surface truss roof steel structure construction method based on crotch column supporting system

Abstract

A curved surface truss roof steel structure construction method based on a crotch column supporting system is characterized in that crotch columns are formed through connection and fixation of a trunk, a first-stage branch and a second-stage branch, then curved surface trusses and flat splicing jig frames are assembled, and finally the curved surface trusses and the flat splicing jig frames are integrally hoisted to the crotch columns to form an integral steel structure. According to the method, the high-altitude problem of a traditional large-span curved surface roof is converted into the ground problem through the closed-loop process of ground integral forming, synchronous hoisting of columns and trusses and one-time connector locking, and the comprehensive target of high efficiency, economy and environment friendliness is achieved while structural safety and curved surface modeling are ensured.

Description

Technical Field

[0001] This invention relates to the field of steel structure construction, and in particular to a construction method for a curved truss roof steel structure based on a tree branch column support system. Background Technology

[0002] As the outermost barrier of a building, the steel roof structure isolates it from wind, rain, snow, ultraviolet radiation, and extreme temperatures, ensuring a stable internal environment and safely transferring loads to the supporting column system. It has become a core solution for modern architecture, balancing safety, functionality, and efficiency. Curved truss roof structures can precisely achieve complex shapes such as hyperbolic curves and twists, meeting the aesthetic requirements of landmark buildings. Combined with oblique grids or triangular trusses to form a spatial force-bearing system, it reduces steel consumption by 30% to 50% compared to planar trusses.

[0003] Existing curved truss applications typically involve on-site cutting of members, adding backing plates, and secondary welding, using planar polygonal lines to fit spatial curves. However, this type of curved truss suffers from accumulated deviations in the welding positions, leading to significant misalignment when the curved truss is closed.

[0004] However, when using conventional support columns, the top cannot be directly matched with the complex spatial nodes of the curved truss. Instead, they can only be arranged at the orthogonal column grid nodes. However, the orthogonal column grid nodes are often misaligned with the natural support positions of the curved surface, which requires the setting of a large transfer layer at the top of the column to forcibly pull dozens of nodes at the edge of the curved surface back to the top of the column. The assembly stress is high, which causes the curved surface to be flattened or wrinkled. On the one hand, this results in structural redundancy, increased steel consumption and construction waste. On the other hand, the continuity of the curved surface is destroyed, and the original streamlined appearance cannot be achieved. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a construction method for a curved truss roof steel structure based on a tree branch column support system.

[0006] The construction method is achieved through the following steps: 1) Construction of the tree branch support system: 1.1 Pre-embedded anchor bolts: Before the foundation is poured, high-strength anchor bolts are pre-embedded in one go using positioning brackets; 1.2 Prefabrication of column segments: The main trunk, primary and secondary branches are prefabricated in segments in the factory; using a cast steel node assembly device, all cast steel nodes are welded to the corresponding branch segments, and the primary branch segments are assembled with the main trunk to form a "Y"-shaped primary unit; the secondary branch segments are pre-assembled with the primary units to form a complete tree branch column; 1.3 Inter-column stabilization system: Rigid connecting beams are installed between the secondary branching sections of adjacent tree branches to form a spatial frame for the complete tree branches; 1.4 Tree branch column hoisting: The entire tree branch column is hoisted in one go, initially aligned after positioning, and secured with guy ropes; 2) Construction of curved trusses: 2.1 Ground segmented curved surface pre-assembly: The curved truss is divided into U-direction main truss and V-direction secondary truss according to the UV coordinates of the hyperbola. It is then laid out in three dimensions on the flat assembly jig to form truss units. 2.2 Flat assembly frame sliding and positioning: Assemble each truss unit into a whole closed curved truss on the ground. Use a laser tracker and a total station to measure and ensure that the misalignment of the closed end is ≤3 mm. Use slippers and winches to slide the curved truss and flat assembly frame as a whole to the hoisting station. 2.3 Overall hoisting: Two crawler cranes are used for hoisting, with the slings at an angle of ≥60° to the horizontal to ensure that the curved truss roof is in a slightly arched state in the air. The height of the slightly arched state is 1 / 300-1 / 500 of the overall span of the curved truss roof. The hoisting points are set at the corresponding positions of the top of the curved truss roof and the tree branch column. 3) Coordinating processes for column-truss assembly: 3.1 Direct Connection Node Setup: A curved multi-directional socket joint is installed at the top of the secondary branch of the tree branch column. The curved multi-directional socket joint is made of cast steel. The axis of the socket joint is consistent with the tangent direction of the edge of the curved roof surface. A wedge-shaped guide groove is provided on the inner wall of the socket joint. An annular damping cavity is reserved at the root of the socket joint. A high-damping rubber pad is pressed into the cavity to absorb the out-of-plane vibration of the curved truss and reduce fatigue stress. A cut wedge-shaped plug is provided at the bottom of the curved truss to achieve three-dimensional one-time alignment. 3.2 After adjustment and alignment, first drive in high-strength bolts to temporarily lock the column-truss joint. Use a total station to remeasure the overall coordinates of the curved truss and use a flat splicing jig to fine-tune the sag of the curved surface. After the remeasurement is qualified, use a combination of full penetration weld and torsion shear type high-strength bolts at the top node of the tree branch column to complete the rigid connection of the column-truss. 4) Support unloading: Using the umbrella-shaped spatial frame formed by the tree branch columns as the fulcrum, the hydraulic staged unloading of the flat assembly frame is used to finally form a column and truss self-balancing system.

[0007] Specifically, the cast steel node assembly device described in step 1.1 consists of a base plate, a frame, telescopic rods, and support rods. The base plate is located at the bottom of the frame. The frame consists of columns and beams; the beams at the bottom of the frame are arranged around the base plate, and the beams at the top of the frame are equipped with telescopic rods and support rods. The telescopic rods are connected to the beams at the top of the frame via universal clamps. The base plate is equipped with a leveling device to adjust the level. The cast steel node is placed on the base plate and is secured with locking blocks to prevent movement of the contact surface. Four support rods are located at the top of the frame to adjust the angle of the cast steel node in conjunction with the telescopic rods. Each of the four sides can slide back and forth horizontally to adjust the fulcrum and prevent instability.

[0008] This construction method transforms the traditional high-altitude challenges of large-span curved roofs into easy ground-level challenges through a closed-loop process of integral ground molding, simultaneous hoisting of columns and trusses, and one-time locking of interfaces. While ensuring structural safety and curved surface design, it achieves the goals of efficient, economical, and green construction. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the structure of the tree branch column and cast steel node assembly device.

[0010] Figure 2 This is a schematic diagram of a curved truss roof structure.

[0011] Figure 3 This is a structural schematic diagram of the joint between the column and the truss.

[0012] Among them, 1: base plate; 2: frame; 3: telescopic rod; 4: support rod; 5: column; 6: beam; 7: universal clamp; 8: support pad; 9: connecting rod; 10: socket joint; 11: wedge plug. Detailed Implementation

[0013] Example 1: The construction method of curved truss roof steel structure based on tree branch column support system is achieved through the following steps: 1) Construction of the tree branch column support system: Before the independent foundation concrete is poured, 16-M30 high-strength anchor bolts are embedded in one go using laser positioning brackets, with a center deviation ≤3 mm and a levelness ≤L / 1000; the column body is prefabricated in sections and assembled at nodes; the main trunk, primary, and secondary branch sections are all cut in the factory; the nodes and pipes are assembled on the ground using a cast steel node assembly device. The cast steel nodes are placed on the device base plate, and the connecting rods are finely adjusted within ±15° in three dimensions using telescopic rods and support pads to temporarily lock the branch pipes. Welders complete the horizontal welding on the movable platform, with a first-pass weld qualification rate ≥98%; the primary branch section is assembled with the main trunk to form a "Y"-shaped primary unit, and the secondary branch section is then pre-assembled with the primary unit to form a complete column; hard connecting beams are welded between the secondary branches of adjacent tree branch columns to form a spatial frame, which meets the overall lateral stiffness requirements during the subsequent hoisting stage; 150 The crawler crane can lift the entire unit (the heaviest single column is 11.1t). After positioning, the guy ropes and jacks are used for initial alignment, and the verticality is ≤H / 1000.

[0014] 2) Construction of curved trusses: Following the principle of "12m / segment for U-direction main trusses and 6m / segment for V-direction secondary trusses", three-dimensional layout is carried out on the flat assembly jig; a laser target is set on the top of the jig, and the curved surface sag error is ≤2mm; the truss units are horizontally assembled on the hardened ground, and the curved surface sag is adjusted in real time with an adjustment accuracy of 0.5mm; the assembled curved truss, together with the jig, is horizontally slid to the crawler crane position using a sliding shoe and a 20t winch, with a sliding speed ≤0.5m / min; a dual-machine 150t crawler crane is used to lift the truss, with the angle between the sling and the horizontal ≥60°, maintaining the truss "horizontal-slightly arched"; the lifting point corresponds to the ear plate at the top of the tree branch column, and the single-point lifting weight is ≤25t, and the truss is positioned in one go.

[0015] 3) Column-truss joint process: Install curved multi-directional socket nodes at the top of the secondary branch of the tree branch column to achieve three-dimensional one-time alignment of the column-truss; after adjusting the aligned curved truss, first drive in φ30 cylindrical pins to temporarily lock the column-truss joint, remeasure the overall coordinates of the curved truss with a total station, and use a flat splicing jig to fine-tune the curved surface sag; after the remeasurement is qualified, use 360° full penetration groove weld and M42 torsion shear type high-strength bolts to finally tighten the rigid node of the column-truss at the top node of the tree branch column to complete the rigid node of the column-truss. 4) Support unloading: Using the umbrella-shaped spatial frame formed by the tree branch columns as the fulcrum, the hydraulic staged unloading of the flat assembly frame is used to finally form a column and truss self-balancing system.

[0016] The beneficial effects of this construction method are mainly reflected in four dimensions: "precision, construction period, cost, and safety". First, improved precision: After the tree branch column completes multi-level branching and overall assembly of cast steel nodes on the ground, the truss unit completes three-dimensional coordinate locking on the flat assembly frame. The two are aligned in one go through guide pins, and the overall roof geometric error is controlled within 1 / 1000, reducing the number of re-measurements by 80% compared with traditional high-altitude bulk assembly.

[0017] II. Shortened construction period: The ground assembly and hoisting are completed in one go, reducing the amount of high-altitude work from 60% to 20% of the conventional plan; the construction period for a single span of the 46m curved roof is reduced from 50 days to 18 days, a reduction of about 64%.

[0018] III. Cost Reduction: Eliminating the large conversion layer saves 15-25% on steel usage; reduces machine shifts by 50% and reduces oxygen, acetylene, and welding material consumption by 30%; based on comprehensive calculations, the direct cost per 100 square meters of roof is reduced by approximately 20%.

[0019] IV. Reduced safety risks: After the high-altitude assembly was changed to ground flat assembly, the risk of falling and being struck by objects was reduced by 60%; the "column-truss" integral unit was adopted in the hoisting stage, the weight of a single hoisting was ≤25 t, the number of hoisting times was reduced by 70%, and the collision hazards of multi-machine hoisting were avoided.

Claims

1. A construction method for a curved truss roof steel structure based on a tree-branch column support system, characterized in that... This can be achieved through the following steps: 1) Construction of the tree branch support system: 1.1 Pre-embedded anchor bolts: Before the foundation is poured, high-strength anchor bolts are pre-embedded in one go using positioning brackets; 1.2 Prefabrication of column segments: The main trunk, primary and secondary branches are prefabricated in segments in the factory; using a cast steel node assembly device, all cast steel nodes are welded to the corresponding branch segments, and the primary branch segments are assembled with the main trunk to form a "Y"-shaped primary unit; the secondary branch segments are pre-assembled with the primary units to form a complete tree branch column; 1.3 Inter-column stabilization system: Rigid connecting beams are installed between the secondary branching sections of adjacent tree branches to form a spatial frame for the complete tree branches; 1.4 Tree branch column hoisting: The entire tree branch column is hoisted in one go, initially aligned after positioning, and secured with guy ropes; 2) Construction of curved trusses: 2.1 Ground segmented curved surface pre-assembly: The curved truss is divided into U-direction main truss and V-direction secondary truss according to the UV coordinates of the hyperbola. It is then laid out in three dimensions on the flat assembly jig to form truss units. 2.2 Flat assembly frame sliding and positioning: Assemble each truss unit into a whole closed curved truss on the ground. Use a laser tracker and a total station to measure and ensure that the misalignment of the closed end is ≤3 mm. Use slippers and winches to slide the curved truss and flat assembly frame as a whole to the hoisting station. 2.3 Overall hoisting: Two crawler cranes are used for hoisting, with the slings at an angle of ≥60° to the horizontal to ensure that the curved truss roof is in a slightly arched state in the air. The height of the slightly arched state is 1 / 300-1 / 500 of the overall span of the curved truss roof. The hoisting points are set at the corresponding positions of the top of the curved truss roof and the tree branch column. 3) Coordinating processes for column-truss connections: 3.1 Direct Connection Node Setup: A curved multi-directional socket joint is installed at the top of the secondary branch of the tree branch column. The curved multi-directional socket joint is made of cast steel. The axis of the socket joint is consistent with the tangent direction of the edge of the curved roof surface. A wedge-shaped guide groove is provided on the inner wall of the socket joint. An annular damping cavity is reserved at the top of the socket joint. A high-damping rubber pad is pressed into the cavity to absorb the out-of-plane vibration of the curved truss and reduce fatigue stress. A cut wedge-shaped plug is provided at the bottom of the curved truss to achieve three-dimensional one-time alignment. 3.2 After adjustment and alignment, first drive in high-strength bolts to temporarily lock the column-truss joint. Use a total station to remeasure the overall coordinates of the curved truss and use a flat splicing jig to fine-tune the sag of the curved surface. After the remeasurement is qualified, use a combination of full penetration weld and torsion shear type high-strength bolts at the top node of the tree branch column to complete the rigid connection of the column-truss. 4) Support unloading: Using the umbrella-shaped spatial frame formed by the tree branch columns as the fulcrum, the hydraulic staged unloading of the flat assembly frame is used to finally form a column and truss self-balancing system.

2. A construction method for a curved truss roof steel structure based on a tree-branch column support system, characterized in that... The cast steel node assembly device described in step 1.1 consists of a base plate, a frame, telescopic rods, and support rods. The base plate is located at the bottom of the frame. The frame consists of columns and beams. The beams at the bottom of the frame are arranged around the base plate, and the beams at the top of the frame are equipped with telescopic rods and support rods. The telescopic rods are connected to the beams at the top of the frame via universal clamps. The base plate is equipped with a leveling device to adjust the level. The cast steel node is set on the base plate and is equipped with locking blocks to prevent the contact surface from moving. Four support rods are set at the top of the frame to adjust the angle of the cast steel node in conjunction with the telescopic rods. The four sides can slide back and forth horizontally to adjust the fulcrum and prevent instability.

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