1. Project Overview

The Jinhua Peking University Science and Technology Park project is located in the first phase of the Jinhua Peking University Science and Technology Park in the east, Bada Road in the south, Jinhua Technician College in the west, and Xinda Forging in the north. The total construction area is 39,956.68 square meters, and the curtain wall area is 16,000 square meters. The fire resistance level is one, the fire resistance limit of the floor fire layer is 2 hours, and the seismic fortification is 7 degrees. The construction cost of the curtain wall of this project is 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 yuan, and 7,000,000 yuan (16,815,760.73 yuan). The owner is Zhejiang Peking University Science and Technology Park Co., Ltd., and Nantong Lanxing Decoration Engineering Co., Ltd. is responsible for the curtain wall construction. The curtain wall construction started on October 25, 2018, and the curtain wall was completed on June 15, 2019.

The construction scope of the curtain wall of the project is framed semi-hidden frame glass curtain wall (the large glass curtain wall on the second floor and above, the first floor and the first underground floor glass curtain wall), aluminum plate ceiling (roof cornice and ceiling on the first floor and the first floor, basement floor) , corridor), stone curtain wall (underground floor), glass railings (south side of the first floor of Block A, sunken courtyard opening, terrace and stairs), indoor door and window guardrail handrails, glass canopy (underground floor top), etc. Among them, the glass curtain wall is 13876.46 square meters; the aluminum plate curtain wall and ceiling is about 2475.09 square meters; the stone curtain wall is about 479.56 square meters; the glass railings are about 850.24 square meters.

The project consists of two office buildings, Block A and Block B, a multimedia center and a basement. Some scientific research exhibition centers are located on the street and on the first floor. Blocks A and B are both deep and shallow, with good lighting and ventilation. The frame-type semi-hidden frame glass curtain wall is used, and the connection method of aluminum alloy core + stainless steel pins is used to moderately optimize the size of the glass and the size of the opening fan, and reduce segmentation, not only The installation speed is improved, which is more conducive to the repair and maintenance of the curtain wall in the future of the project. The high-efficiency and energy-saving glass curtain wall system and the wide application of energy-saving equipment create a panoramic office experience, greatly improve the use quality and comfort of the office building, and save energy.

From the design source to the implementation of the construction layer by layer, the project focuses on the control of the junction of the curtain wall, the end of the curtain wall itself, and the settlement joint, and most of the assembly work is completed in the factory. Colleagues who reduce the workload of quality inspection on site, Ensure the installation quality and installation accuracy.

2. Overview of the project technology system

The engineering system mainly includes: vertical and horizontal glass curtain wall, stone curtain wall, aluminum plate curtain wall, aluminum plate ceiling, glass railing, point-type glass canopy, aluminum alloy external swing door, aluminum alloy shutter, etc.

1. Vertical and horizontal glass curtain wall system: It is mainly located on the large surface of the front façade. E+12A+6 tempered insulating glass, 8LOW-E+12A+8 tempered insulating glass is used locally, 6mm single-piece tempered glass is used between layers, and 12LOW-E+12A+12 tempered insulating glass is used for the first floor. The decorative buckle cover is made of 65mm wide aluminum alloy profile.

2. Stone curtain wall: It is mainly located on the façade of the first underground floor, and adopts aluminum alloy SE pendant short slot dry-hanging form; the stone column adopts 120x60x4mm steel square tube (Q235B), and the beam adopts L50*4 angle steel (Q235B); the panel adopts 28mm rough granite stone.

3. Aluminum sheet curtain wall and suspended ceiling: mainly located at the roof cornice and the ceiling plate on the first floor and basement floor, the column adopts 120*60*4 steel square tube (Q235B), the beam L50*5 angle (Q235B); the profile is hot-dip galvanized . The panel adopts 3.0mm aluminum veneer.

4. Glass railing: 12x100mm stainless steel column (316), 30x100x2mm concave stainless steel handrail (316), glass panel is 6+1.14PVB+6 laminated tempered glass.

5. Point glass canopy: The main keel is made of 12.6# I-beam (Q235B), the secondary keel is made of Φ50x4 steel round tube, the steel surface is treated with fluorocarbon paint at room temperature, and the glass panel is 6+1.14PVB+6 laminated tempered glass.

3. Key points, difficulties and targeted measures in construction

This project includes stone curtain wall, frame glass curtain wall, aluminum plate curtain wall, awning, glass railing and aluminum alloy 100-page, etc. There are many systems, the construction overlapping surfaces are complex, the front and rear relationships of key nodes are compact, and the rows are multi-system, multi-faceted, multi-layered. The mass building form of the block.

The main quality control points of the curtain wall: welding of steel components, riveting strength, structural safety and installation accuracy; in addition, stone and dry-hanging ceramic bricks need to be prevented from falling; the main control point of appearance effect is color difference control.

Before construction, make the sample first, and the sample must reflect its material, function and construction technology, and be approved by the designer, the contractor and the supervision engineer. The approved sample will be used as one of the standards for testing related projects and processes, and the sample The source must be the actual source of the engineering supply, showing its quality, model, finish, origin, tolerances and other required characteristics. Process inspection, data collection, model acceptance, organize operators to observe the model, and make on-site disclosures. The quality of the model is regarded as the minimum standard of project quality. In large-scale construction, the construction quality shall not be lower than the quality of the model.

Re-testing of materials shall be carried out first, and the use of unqualified products shall be resolutely eliminated. Raw materials shall be strictly in accordance with the specification requirements according to the material procurement plan, and the inspection of raw materials shall be strengthened, and the inspection and delivery of samples shall be organized to obtain raw material test information, and the quality responsibility caused by the use of unqualified materials shall be investigated by the acceptance personnel.

1. The exterior curtain wall project of this project has a large volume, many and complex systems, and material processing, transportation, storage yard and installation as a whole. The progress of the exterior decoration project is the key point of this project.

Small material stacking site Because the project is located in the center of Jinhua, and the building density is high, the site for our material stacking is small, and our glass curtain wall construction requires a large site for material stacking. Therefore, we need to organize the entry of materials in a very orderly manner. In addition, there are many uncertain factors on the construction site, which will be a major difficulty for our company's construction.

Our company regards this project as a key project. The ability of the processing and assembly plant can fully meet the needs of this project. Through reasonable arrangements for the number of vehicles, routes and local traffic control conditions of the special transport fleet, the installation components and plates can be fully guaranteed. supply. And in the structural design, it is optimized through design and calculation, and a specially designed transportation turnover frame is used to ensure that no damage will occur during material transportation.

2. Edge closing, closing and glue joints, and line follow-up are the key and difficult points of curtain wall construction.

Edge closing is the key point of construction for every curtain wall project. The quality of closing edge directly affects the quality of curtain wall construction. 30% to 40% of the workload of curtain wall construction is at the edge and the edge, and the edge of the edge is closed. If the closure is not handled properly, it is easy to cause water leakage. Therefore, the junctions of different types of curtain walls, the closing parts of the curtain walls themselves, settlement joints and other places are the key objects to be controlled in the construction. We are required to be meticulous, keep improving, strictly follow the construction technology and adopt scientific and effective methods for construction, and ensure the quality of installation. and installation accuracy. The level and straightness of the line is the key factor for the beauty of the curtain wall. From the design source to the construction implementation, it must be considered in advance, and it is impossible to think where it is.

Specific part cases:

2.1. The horizontal span of the main body is large, and the traffic circle of the horizontal seam is problematic;

2.2. How to ensure the beauty and straightness of the glue joints for different systems of glue joints, aluminum plate glue joints and glass curtain wall joints, and the hard closed parts of the structure; with aluminum materials, the aluminum materials can be hard closed and straight, but the civil structure is not straight;

2.3. Curtain wall undercover beam and ceiling beam and indoor closing;

2.4. Where is the exit of the curtain wall and the hydroelectric wind, the outlet of the pressurized air supply and the supplementary air and smoke exhaust;

2.5. The relative relationship between the door and the indoor and outdoor floor coverings and the elevation ensures that the door can be opened smoothly;

Fixing and looping of glass panels

3. There are many retreat layers and many transfer layers, and the construction of scaffolding leads to the inversion of the process.

Specific part cases:

3.1. At the grooves above the 5th floor, the construction is very difficult, whether scaffolding or hanging baskets;

3.2. The construction of the ceiling on the first floor is difficult, especially the system that is not considered by the scaffolding;

3.3. In the construction process, the upper part of all glass is pressed by aluminum plate, and the welding of aluminum plate is steel frame must be completed before the glass is installed; the fire must be closed in advance; the use of scaffolding construction leads to the inversion of the process; the aluminum plate must be collected first and then the glass;

3.4. For the construction of the transition layer of the setback, the treatment of the closing of the setback part, and the parts that are easily ignored, the design should focus on optimization;

4. The structure safety, the guarantee of the use function, the life-long quality guarantee of the curtain wall, and the quality of the century-old plan.

Specific part cases:

4.1 Fixing of the embedded adapter

1. The embedded parts take root on the structure, some parts have no structure or concrete structure, how to root the embedded parts;

2. How to ensure the effective weld length when the adapter takes root on the main body and on the steel structure;

4.2 Curtain Wall Construction Measurement

The measurement of the grid axis of the curtain wall should be coordinated with the measurement of the main structure. For the error of the main structure, corresponding adjustments should be made in time to ensure that the processing and production conform to the actual situation on site; Check the position of the curtain wall.

4.3 Curtain wall waterproofing

The reasonable design of the curtain wall profile is one of the important measures for waterproofing. The profile is designed as a pressure balance system. The system is based on the principle of rain curtain. A guide hole is preset on the curtain wall profile for external pressure to enter the interior, so that the difference between the internal and external pressures Adjust the balance to achieve the purpose that the external water is not easy to enter. At the same time, small drainage holes are opened on the outer edge and lower part of the profile to drain a small amount of seepage water entering the interior or dew condensation water in the room. The above waterproof and drainage measures together form a dry sealing system. On the one hand, it is not easy for water to enter the interior of the curtain wall, and on the other hand, even if there is water infiltration, it will be automatically eliminated. When presetting holes, there are 2 holes on each horizontal frame, the holes are about 100mm away from the corners, and the horizontal distance between the upper and lower holes is greater than 50mm to prevent air collusion.

4.4 Construction of sealant

The construction thickness should be greater than 3.5mm, the construction width should not be less than 2 times the construction thickness, and the bottom of the deep sealing groove should be filled with polyethylene foam; Knot.

4.5 Acceptance of concealed works of curtain wall installation and construction

Cooperate with the owner to carry out concealed engineering acceptance, such as: installation of connection nodes between components and main structure; installation of gap nodes between curtain wall and main structure; installation of curtain wall expansion joints, settlement joints, anti-vibration joints and wall corner joints, and curtain wall lightning protection Installation of grounding nodes.

4.6 Technical Guarantee Measures for Curtain Wall Fire Protection

The fire protection design of this project is guided by GBJ16 and GB50045, with a larger safety factor. The main fire protection technical measures are:

According to the overall design and requirements of the building's fire protection zone, fireproof materials (fireproof rock wool, fireproof board, fireproof glue, etc.) are used to set up fireproof isolation belts related to the curtain wall. Try to avoid a large piece of glass across the upper and lower fire compartments of the floor. If the beam and the floor structure are far apart due to the appearance of the grid, 1.5mm thick fire-resistant galvanized steel plate and fire-resistant rock wool should be used to connect the beam to form a fire partition;

The interlayer fire protection is located at the upper and lower edges of the building structure. Fireproof partitions made of 100mm thick fireproof rock wool and 1.5mm thick galvanized iron plates are used for continuous laying. The fireproof rock wool is installed on the galvanized steel plate, and the galvanized steel plate is fixed on the horizontal profile and structure on the edge. Interlayer diffusion of pyrotechnics can be prevented safely and reliably. The filling material of the fire line adopts non-combustible material;

Interval treatment of fire zones on the same floor, clear responsible parties, and use non-combustible materials to separate the two zones;

Use materials that meet the requirements of fire protection regulations to control the processing quality. The gap at the edge of the board should be less than 3mm, and the fireproof rock wool should be filled with dense, no gaps;

All anchor points of supporting curtain walls are protected by 2-hour refractory materials, specifically, a closed box with a height of 100mm made of 1.5mm thick galvanized steel plate, filled with solid fireproof rock wool, and the whole is fastened to the transfer system, and the It is fastened and sealed with the floor structure;

Appropriate fasteners should be selected for fixing around the pallet according to the different materials of the connected parts, and the distance between the two fixing points is 350~450mm;

Ensure that the selected materials meet the fire protection requirements stipulated by the state, and shall not use materials that are flammable or produce toxic gases in case of fire, etc.

Curtain wall fire protection technical advice:

Each floor is equipped with automatic fire alarm equipment and automatic fire extinguishing system;

Set smoke exhaust measures within a certain height;

4.7 Guarantee measures for curtain wall wind resistance technology

1. Technical requirements for anti-deformation of curtain wall

According to the relevant national and ministries and local regulations and regulations, the structural displacement design:

The wall should be able to adapt to the deflection, material deformation, inclination or sliding of the building and the curtain wall itself due to wind force, temperature change, earthquake force, etc.;

The plane deformation rate r of the curtain wall needs to be greater than the displacement rate of the main structure, which is taken as 1/300 < r < 1/200 according to the national standard, grade IV.

4.8 Technical measures for anti-deformation of curtain wall

Wind pressure deformation has two effects on the curtain wall, namely direct effect and indirect additional effect.

The direct effect means that the wind load directly acts on the curtain wall material to cause damage (such as the rupture of glass, the failure of the rod, etc.). The preventive measure is to meet the design strength, stiffness and allowable stress of various curtain wall materials through mechanical calculation.

The additional effect refers to the displacement of the main frame of the building and the main frame of the curtain wall caused by wind pressure, and the damage of the curtain wall caused by various internal stresses. This needs to be overcome from the specific structural design and conceptual design of the curtain wall, such as:

All points are suitable for large deformation requirements.

The curtain wall anti-seepage and drainage technology guarantee measures are all installed in a floating form, which is convenient for stress release and deformation requirements.

The vertical expansion joint is 20mm, which meets the requirements of plane deformation rate.

Satisfy the gap between the plates, the panel and the frame.

Flexible transfer between the curtain wall and the main structure.

Overall, the technical solution needs to be a flexible system that can be charged

The conditions and solutions for the leakage of the curtain wall:

The following three conditions are indispensable for curtain wall leakage: water; pressure difference; leakage path.

Among them, water cannot be eliminated. Only by trying to eliminate the remaining two factors can prevent the leakage of water. The frame system of this project uses the outer sealing strip and the inner sealing strip to form a double seal to solve the phenomenon of water seepage.

Measures to discharge a small amount of leakage water:

No matter how perfect the curtain wall system is, it is impossible to rule out a small amount of water seepage caused by man-made construction factors. The curtain wall system must take necessary external drainage measures:

Use caulking tape to block a large amount of rainwater on the outer surface of the canopy to prevent water from entering.

If a small amount of rainwater and dew condensation water enters the profile cavity of the curtain wall, the water will be led to the outside through the method of "water collecting tank, water guiding tank and external drainage hole", which can be clearly seen in our plan.

How can the canopy ensure smooth drainage and no dust accumulation?

4.9 Stone slotting

Stone grooving is an important key process. For this process, it is necessary to control the quality