Analysis of the major difficulties in the construction of stone curtain wall, novice learning!

1. Different curtain wall joint treatment measures

The treatment of different curtain wall joints is also the focus of the construction of this project. The treatment measures at the joints of different curtain walls are based on the design drawings: the foam rods are filled in the gaps and then sealant. The rubber surface should be flat and smooth.

The interface between the stone and the window is a special part. Therefore, the part involves the contact between different materials of stone and aluminum, and waterproofing is particularly important here. Therefore, the contact part between the window and the stone is first filled with foam waterproof agent to ensure the waterproof performance of the interface, and the gap between the stone and the window is filled with silicone weather-resistant adhesive with excellent performance after the foam agent is dry, so as to ensure that the gap is impermeable for a long time and has good waterproof performance.

Second, stone slotting

Stone grooving is an important key process, for this process to control the quality of the first is to ensure that the equipment is in the best working condition, followed by the selection of serious and responsible, experienced operators to operate. In the end, by slot-by-groove testing, all those who do not meet the process requirements will be discarded to ensure that the stone curtain wall is foolproof in safety. When the steel keel installation is completed, a stone slotting machine is added for on-site emergency stone slab slotting.

Third, the construction of steel structure focus

The anti-corrosion of steel structure is the focus of construction. Stone curtain wall steel keel hot-dip galvanized treatment. The hardware fittings are made of stainless steel. When welding on site, the welding part must be treated with anti-corrosion, and the thickness of the galvanized coating shall not be less than 75um. Steel corner codes, connectors, etc. are hot-dip galvanized. During the construction of exposed steel frame coating, construction, rain and fog, it is not allowed to be constructed (especially the surface coating, construction is strictly prohibited). The environment should be clean, the surface must be dry, there should be no moisture, the temperature should not be lower than +15 °C, and the relative humidity should not be greater than 60%. During the construction process, attention should be paid to the change of climatic conditions, and when there is strong wind, rain and fog, construction should not be carried out (especially the surface coating, construction is strictly prohibited)

Fourth, curtain wall construction survey

The measurement of the grid axis of the curtain wall should be coordinated with the measurement of the main structure, and the error of the main structure should be adjusted accordingly in time to ensure that the processing and production conform to the actual situation of the site; the measurement should be carried out under the condition that the wind force is not greater than level 4, and the position of the curtain wall should be checked regularly every day.

5. Waterproof curtain wall

The reasonable design of the curtain wall profile is one of the important measures of waterproofing, and the profile is designed as a pressure balance system, which is based on the principle of rain curtain, and presets an external pressure on the curtain wall profile to enter the internal guide hole, so that the internal and external pressure difference is adjusted and balanced to achieve the purpose that the external water is not easy to enter. At the same time, there are drainage holes on the outer edge and lower part of the profile to drain a small amount of seepage water or condensation water in the room that enters the interior. Together, the above waterproofing and drainage measures form a dry sealing system, which on the one hand makes it difficult for water to enter the interior of the curtain wall, and on the other hand, it will automatically remove water even if it penetrates. When presetting holes, there are 2 holes on each frame, the holes are about 100mm away from the corner, and the horizontal distance between the upper and lower holes is greater than 50mm to prevent air collusion.

Sixth, the construction of sealant

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

7. Acceptance of concealed works for curtain wall installation and construction

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

8. Technical guarantee measures for curtain wall fire protection

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

1. According to the overall design and requirements of the building fireproof partition, the fireproof materials (fireproof rock wool, fireproof board, fireproof adhesive, etc.) are used to set up fireproof isolation belts related to the curtain wall. Try to avoid a large piece of glass across the floor above and below the two fireproof partitions, if the beam and the floor structure elevation need to be far away due to the appearance of the grid, should be used 1.5mm thick refractory galvanized steel plate and fireproof rock wool to connect with the beam to form a fireproof partition;

2. The inter-layer fireproof setting is located at the upper and lower edges of the building structure, each of which is made of 100mm thick fireproof rock wool and 1.5mm thick galvanized iron plate to make the fireproof partition through the long laying, and the fireproof rock wool is installed on the galvanized steel plate, and the galvanized steel plate is fixed on the transverse profile and the edge of the structure. The interlayer diffusion of pyrotechnics can be safely and reliably stopped. The filling material of the fire line is non-combustible material;

3. Interval treatment of fire prevention zones on the same floor, clarify the responsible party, and use non-combustible materials to separate the two partitions;

4. Use materials that meet the requirements of fire protection specifications to control the processing quality. The gap along the edge of the board should be less than 3mm, and the fireproof rock wool should be filled with dense and seamless gaps;

5. All anchor joints supporting the curtain wall 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, buckled on the transfer system as a whole, and fixed and sealed with the floor structure;

6. The surrounding of the supporting plate should be fixed firmly with appropriate fasteners according to the different materials of the connected parts, and the spacing between the two fixing points should be 350~450mm;

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

8. Technical suggestions for curtain wall fire protection:

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

(2) Set up smoke exhaust measures within a certain height;

9. Technical guarantee measures for curtain wall wind resistance

(1) Technical requirements for curtain wall anti-deformation

According to the relevant norms and regulations of the state, ministries and local governments, the design of structural displacement:

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

2. The plane deformation rate r of the curtain wall should be greater than the displacement rate of the main structure, and 1/300 "r〈1/200, grade IV" should be taken according to the national standard.

(2) Technical measures for anti-deformation of curtain wall

Wind pressure deformation has two effects on curtain walls, namely direct effects and indirect additive effects.

The direct effect refers to the direct effect of wind load on the curtain wall material to produce damage (such as the fracture of glass, the failure of members, etc.), and the prevention measures are to meet the design strength, stiffness, allowable stress and so on 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, as well as the destruction of the curtain wall due to various internal stresses. This should be overcome from the specific structural design and conceptual design of the curtain wall, such as:

1. All plates are installed in floating form, which is convenient for stress release and deformation requirements.

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

3. Meet the gap between the plates, the panel and the frame.

4. Flexible transfer between the curtain wall and the main structure.

5. On the whole, the technical solution needs to be a flexible system, which can fully adapt to the requirements of large deformation.

10. Curtain wall seepage prevention and drainage technical guarantee measures

1. Conditions and solutions for curtain wall leakage:

2. The following three conditions are indispensable for the leakage of the curtain wall: water, pressure difference, and leakage path.

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

4. Measures for the discharge of a small amount of leakage water:

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

(1) Use caulking strips to block a large amount of rainwater on the outer surface of the canopy to prevent water from entering.

(2) If a small amount of rainwater and condensation water enters the profile cavity of the curtain wall, the water is drawn to the outside through the method of "water collection tank, water guide tank, and external drainage hole", which can be clearly seen in our plan

Transferred from: Stone Research Society, supervision