A curtain wall is the exterior wall enclosure of a building, which is a light wall with a decorative effect commonly used in modern buildings. As the “coat of architecture”, the curtain wall has increasingly become an important element of the urban environment, but it often costs “heavy money”, and may not be able to get an ideal appearance. It is the common aspiration of designers to have a clean and elegant building facade, visual enjoyment, and space experience. Under the same cost configuration standard, all skills are cost controlled.
Stone curtain wall technology
① Wet pasted stone curtain wall:
The traditional wet pasting is the old process of adding reinforcement mesh to the wall, fixing the plate with copper wire, and pouring cement mortar into layers. This process has many disadvantages when applied to the exterior wall, not only because of calcium bicarbonate precipitation (whitening frost) and water stains after the cement mortar is pasted on the board, which make the wall stone color change, form color difference and pollute the wall; Moreover, due to temperature change and other reasons, it is easy to cause wall hollowing, cracking, and even falling off. Therefore, it is gradually eliminated.
② Dry hanging stone curtain wall:
There are many kinds of dry pendants, and each kind of pendant has its own installation method. The dry hanging method is directly related to the structure, installation, comprehensive cost, and beauty of the curtain wall. Since it was introduced from abroad in the mid-1980s, the dry hanging method of stone curtain walls has become increasingly innovative, evolving from pin type, butterfly type, etc. to back hanging and seam hanging.
The development and progress of dry hanging technology have completely separated from the monopoly of foreign technology and have developed their own patented dry hanging technology, which has played a positive role in the reform and standardization of domestic dry hanging curtain wall decoration.
The dry hanging method of the exterior wall facing stone is to use high-strength corrosion-resistant metal pendants to fix the facing stone on the exterior surface of the building by means of a bracket, hanger, pin, and bolt. Reasonable pendant design and strict construction technology are the keys to ensuring the safety and beauty of exterior decoration stone.
Dry hanging construction replaces the traditional wet work construction by means of prefabrication and assembly, and its advantages are mainly reflected in:
a. It can avoid surface pollution and discoloration “anti-alkali”, and keep the color luster of the slate.
b. It can avoid wet operations, be less affected by climate change, and save the cost of winter construction and rain construction.
c. It can avoid stones from falling off and reduce maintenance costs.
d. Continuous operation can improve the construction speed.
e. The deadweight of the structure is reduced and thermal insulation space is reserved.
③ Inverted stone curtain wall:
Stainless steel T-shaped pendant shall be used for hanging upside down stone, and it is better to use a back bolt system pendant from the perspective of safety
The back bolt and long bolt shall be used for reliable mechanical fixation, and the back of the stone shall be pasted with protective cloth.
Stone curtain wall cost
① Comprehensive unit price analysis
Price composition of normal stone curtain wall project. It can be seen that the cost of main materials accounts for more than 60% of the price, and the labor cost is the price factor that accounts for the second most.
② Selection of stone curtain wall system
There are three ways to hang stone curtain walls, as follows:
(1) Aluminum alloy back bolt hanging piece: aluminum alloy hanging piece is a new type of back bolt stone dry hanging piece, which can be used to satisfy the construction of today’s city exterior wall dry hanging, and is a substitute for stainless steel hanging pieces. Aluminum alloy pendants are stone dry pendants made of aluminum alloy materials. Compared with other materials, aluminum alloy has the characteristics of lightweight and high strength. In addition, the greatest feature is that aluminum alloy does not rust. Aluminum alloy pendants are made of aluminum alloy materials, which are not easy to deform and are more solid after oxidation treatment.
(2) Aluminum alloy SE pendant: SE aluminum alloy pendant is a combined pendant, which has high strength, strong solidity, and improved seismic function. With angle steel as the secondary keel, its bearing load can be added, which can meet the requirements of increasing the plate size.
There is no connection between the upper and lower plates of such a dry pendant and plate, so there will be no uncertain stress concentration formed by the corresponding connection. The stress is concise and clear, and the bending strength of the plate can be fully utilized under the normal operation state. When the main structure has a large displacement or a large temperature difference, there will be no additional stress in the plate, so it is especially suitable for high-rise buildings and earthquake-resistant building curtain walls. It is a removable and movable stone curtain wall in the real sense.
(3) L-shaped stainless steel stone pendant: L-shaped pendant is a variation of a T-shaped pendant, which is also made of aluminum alloy and stainless steel. The plate pendant is independent and has good removability. It can be adjusted independently according to the processing accuracy of the plate. It has high installation accuracy and can withstand large interlayer deformation
The cost of stone curtain walls can be optimized through three aspects: stone material replacement, line optimization, and keel optimization.
(1) Material replacement:
Weathering sealant for stone, epoxy resin dry hanging adhesive, and marble adhesive, accounting for about 7.8%. The plate separation is increased, the amount of glue joints per square meter is correspondingly reduced, and the use ratio is also reduced
Replacement: replacing the secondary parts with real stone paint and the integrated board can effectively reduce the cost of the outer eaves
Thickness: The lower the thickness is, the more economical it is. The cost increases by 20% from 25 to 30 mm
Width: the cost of plates will increase by 3%~5% for every 100mm increase in width.
Surface treatment: matt surface, polished surface, low cost, easy to control the flatness of the senses
(2) Line optimization:
1. The flatness requirements of the construction process on the construction wall surface: the deviation of the 2m guiding rule against the wall surface shall be less than 5mm.
2. Other construction procedures such as wall installation, and window, and door openings have been completed and accepted.
3. Base course cleaning:
① Clean the remaining floating plaster, release agent oil stain and other sundries on the concrete wall, and the hollow part of the plastering.
② Remove the cracked concrete blocks, inclusions, hollows, etc. at the wall joints, and repair them again; The overhanging eaves of the window sill shall be sloped with cement mortar according to 2%, and various openings of the external wall shall be filled tightly.
③ It is required that the surface flatness deviation of the pasted polystyrene board shall not exceed 5 mm. If the deviation is out of tolerance, the protruding part of the wall shall be polished and the concave part shall be repaired.
(3) Keel optimization:
The most suitable materials for the main keel (steel frame, column) of the stone curtain walls are mainly channeled steel and rectangular steel pipe of carbon structure, followed by other alloy materials. According to the practicality and operability of the project, most of them are carbon steel. Among them, Q235 has moderate carbon content, and good comprehensive properties and its strength, plasticity, welding, and other properties are well-matched. It is the most widely used.
Detail optimization of stone curtain wall
The joint parts shall be optimized according to the details of the plan. The stone column and glass joint shall be connected at right angles to make the whole more beautiful, reduce construction errors, and save labor and later maintenance costs.