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Case Example

Comprehensive Construction Technology of Steel Structure and Roof Curtain Wall of Football Field

Fast Steel Factories Co., Ltd.-----Project Case

Comprehensive Construction Technology of Steel Structure and Roof Curtain Wall of Football Field

1.   Main steel structure construction technology

The main structure of this project is the grandstand system, which is also the support structure of the steel structure roof system. The steel structure frame plus buckling restraint support structure system and prefabricated fair-faced concrete prefabricated grandstand board are used, which also reflects the Fast Steel Factories Co. , Ltd.'s precision steel structure accessories, this is the first innovative application of steel structure prefabricated stand system in domestic stadiums. There are 2 floors of stands in this project. Except for the four corner areas on the lower floor and some stands below some VIP seats, cast-in-place concrete is used, and the rest are made of L-shaped prefabricated fair-faced concrete.

 

Structure drawing of steel grandstand and steel roof system

Both the steel structure and the prefabricated stand unit panels are hoisted with high precision by the integrated inter-node hoisting method of crawler cranes. The stand unit panel support connectors and the main steel components are processed as a whole in the factory to ensure quality and precision.

2. Flexible steel roof construction technology

structural system

The spoke-type tension structure system is widely used in the roof structure of top stadiums at home and abroad because of its light structure and high efficiency of space force structure. This structural system is generally composed of an outer pressure ring, a radial cable and an inner pull ring. The outer pressure ring is similar to the rim of a wheel, the radial cable is similar to the spokes of the wheel, and the inner pull ring is similar to the hub of the wheel. The three form self-balancing. For use in circular or oval-like stadiums.

According to the requirements of quasi-rectangular building shape, the structural design of the steel roof of this project is the first to create a tension structure system with a central pressure ring. This also shows the strength of Fast Steel Factories Co., Ltd. in the precision of steel. It is the sophistication of materials that makes engineering better down the line. The lower chord adopts a tension cable system, and the upper chord adopts a rigid structure system. The horizontal component force of the radial cable is transmitted to the middle pressure ring through the rigid upper chord radial beam to form a tension self-balancing system, and the rigid upper chord structure can reliably support the upright lock. side metal roof.

Schematic diagram of roof steel facade

A total of 46 radial cable trusses are installed in the roof steel structure, which are connected by the main pressure ring beam, the ring cable and the secondary ring beam. The whole system is supported by the steel column on the lower stand steel structure. The central pressure ring tension structure system is a kind of flexible structure, and the internal force is closely related to the configuration. Design requirements.

 

Structural analysis and detailed design

The central pressure ring tension structure system of the roof of this project is a rigid-flexible composite structure that needs to be formed by construction. size. The Shanghai team and Lugang Iron and Steel cooperated with each other based on the structural configuration and cable force distribution in the forming state of the structure, and obtained the zero stress state of the structure through construction simulation analysis, and based on this, a detailed design model and a detailed drawing of the initial state of the components were established. , so as to provide a reliable basis for the precise processing of components.

Deepening model of roof steel structure

 

manufacture

The central pressure ring bears the radial pressure of the 46 radial cable trusses in a balanced manner. The machining and installation accuracy of the pressure ring components will directly affect the mechanical form of the overall tensile structure system. The cross-sectional size of the overall pressure ring is 1.5m×1.5m, the total length is about 424m, and it is divided into 46 sections in total. The flanges are used for mechanical connection between the components, and the processing and manufacturing precision is extremely high. When manufactured in the factory, the 46-section pressure ring beams are all pre-assembled by information simulation and assembled in batches for double control to ensure the accuracy standard.

Middle pressure ring assembly in batches

 

Eight ring cables are connected to the radial cable truss through cable clips, which balance the radial tension of the 46 radial cable trusses. Different from the traditional all-cast steel cable clamps, a new type of cable clamp system of "upper and lower cast steel splints and intermediate key-shaped steel lugs" is adopted. The clamping system is mechanically fixed, and the safety and reliability are greatly improved. During the processing and production, professional quality control personnel are sent to the factory to strictly control the welding quality of components and the accuracy of finished products. Both radial cables and annular cables use Galfan closed cables, which improves the corrosion resistance of the cable system.

Cable clamp construction diagram

installation and tensioning

In view of the structural characteristics of the synchronous control of force and shape in this project, the project team developed a spoke-type cable net construction technology based on tension-compression control brackets. The tension-compression control bracket supports the middle-pressure ring before the radial cable is tensioned, and the middle-pressure ring can be pulled by the vertical control cables in the bracket after the radial cable is tensioned. During the whole tensioning process, the pressure ring is always at the design initial state elevation. After the construction of the secondary structure and part of the roof is completed, release the vertical control cable in the support to complete the overall unloading of the structure and achieve the dual control requirements of force and shape.

 

The roof steel structure construction is mainly divided into six stages. (1) Use the tension-compression control bracket to install 46 radial beams, V-braced outer limbs, pressure ring beams, and uprights under the outer ring beam. (2) The 16-segment loop cables are connected end-to-end to form 8 loop cables, which are fixed with cable clips. The installed roof structure is used to lift the cable clip and the loop cable connected to it. After the cable clip is in place, the cable clip and the installed V-bracing outer limb are fixed by pins. (3) One end of the radial cable is connected with the cable clip, and the other end is connected with the lug plate at the outer end of the radial beam through the tensioning tool. The radial cable is tensioned synchronously, and is fixed through the pin shaft after it is in place. (4) The secondary ring beam on the outer side of the missing compression ring beam forms a complete ring beam, and the roof support and the inter-column support are installed. (5) Install the V-braced inner legs, radial cantilever beams, ring beams on the inner side of the pressure ring beams, and roof support and other secondary structures, so far the roof steel structure is formed. (6) When part of the roof construction is completed, release the vertical control cable in the support to unload the structure as a whole.

                                 

 Central-mounted pressure cycloclone

 

 

  

The loop rope is lifted into position

 

 

 

 

Prepare the radial cable for tension

 

 

 

Steel structure roof and part of roof finished

3. Roof construction technology

The roofing project consists of two upper and lower layers, with a total area of more than 50,000 square meters. The upper layer is mainly composed of polycarbonate sunlight panel lighting belt, aluminum honeycomb panel double-layer metal roof system (step area), aluminum honeycomb panel double-layer roof system (curved area), middle gutter and outer gutter system; the lower layer is mainly composed of It is composed of aluminum composite panel inner and outer cornice system, membrane structure and annular decorative belt.

 

Roof profile diagram

 

The steel roof of this project is a flexible tension structure, which is more sensitive to the roof load. When designing the roof, fully consider the dynamic deformation during the construction of the roof steel structure, and design adjustable connection nodes that can match the deformation amplitude; during the roof construction, the symmetrical installation is adopted in different zones to balance the continuous roof load applied during the construction process. , to eliminate the adverse effect of roof load on the main steel structure.

Installation of roof decoration board

 

 

The lower membrane structure is a reverse hanging tensile membrane, which is the ceiling structure of the stadium roof. Considering factors such as construction safety and the protection of finished membrane materials, the construction of the membrane structure ceiling should be carried out after the metal roof is closed. Membrane structure ceiling adopts unit installation. The membrane material and the unit frame are assembled on the ground to form a membrane structure unit, which is sent to the installation position through a specially designed lifting device, and is connected with the main structure by bolts.

 

The facade curtain wall of this project covers an area of more than 40,000 square meters, mainly composed of curved unitary composite panels, texture panels and other systems. The overall effect of the façade is bowl-shaped, with its horizontal horizontal and vertical vertical cornice edges, so that the façade curtain wall panels present a staggered distribution of single and double curves. In order to ensure the architectural effect of the curved unit slab, the project team innovatively uses the information-based model simulation technology and the integrated construction technology of the steel structure curtain wall to digitally control the quality and accuracy of the construction life cycle at each stage of "deepening, processing and installation".

Steel structure grid

 

 

In the detailed design stage, parametric modeling and steel structure curtain wall clamping technology are used to analyze the spatial relationship and optimize the system layout. According to the architectural division of the outer skin of the curtain wall and the plate, the steel system skeleton, aluminum profile keel, and unit plate can be quickly made. And three-dimensional adjustable adapters, the Shanghai team automatically extracts the material specifications and quantities according to the algorithm, and places the order accurately. In the component processing and unit assembly stage, the information-based simulation pre-assembly technology is used to ensure the machining accuracy of the unit plate through the detection and control of the deviation between the theoretical and measured values of the unit plate control points. During the on-site installation stage, the three-dimensional control coordinates are extracted from the model to perform spatial measurement and positioning of each process from the inside to the outside. To ensure the construction quality of the unit plate.

 

Information model and field measurement and control linkage

In addition, Fast Steel Factories Co., Ltd., in order to ensure the appearance effect of the curved composite unit plate, follows the arc changes of the curved plate, and the column and beam keel system adopts the bending aluminum alloy profiles with the same curvature, which is improved by precise process control. engineering quality.

 

The design of the football field pioneered the central pressure ring and spoke tension structure system and the porcelain bowl-shaped facade curtain wall. In the face of engineering construction problems, the scientific and technological team of Shanghai Construction Machinery Group and Fast Steel Factories Co., Ltd. took advantage of two integrations. The scientific and technological team of Shanghai Construction Machinery Group innovatively developed a wheel-spoke type of Cable net construction complete set of construction technology, Fast Steel Factories Co., Ltd. provides precision steel structure configuration, and the combination of two and two realizes the lean construction of the steel structure roof and curtain wall project of Pudong Football Stadium.