Key points and precautions for glass curtain wall construction

Preparation of important documents

Before commencing the construction of glass curtain walls, it is imperative to ensure that all relevant documents are properly prepared, including construction drawings, technical specifications, and safety operation procedures. These documents serve as crucial guides during the construction process, enabling the smooth progress of the work.

Exploring the construction technology of glass curtain walls on the facades of building exteriors

Glass curtain walls play multiple roles in architecture. They not only bear the important responsibilities of load-bearing and seismic resistance, but also integrate various practical functions such as thermal insulation, wind resistance, waterproofing, and noise prevention. At the same time, they also serve as important decorative elements of the building's exterior, enhancing the aesthetics of the building. However, due to their complex structural characteristics, the construction technology requirements for glass curtain walls are quite high. This article aims to deeply analyze the key technical points of the construction technology for glass curtain walls on the facade of building exterior walls, to help us better understand and master this crucial technology.

I. Overview of glass curtain wall facades on building exteriors

Glass curtain walls, as decorative outer layers of mirror glass on the facades of building exteriors, require meticulous craftsmanship. By incorporating trace elements such as cobalt, iron, selenium, and nickel into float glass and undergoing tempering treatment, transparent plate-like glass emerges. This type of glass can effectively absorb infrared rays and reduce the amount of sunlight penetrating into the interior, thus achieving the effect of indoor cooling. During the construction process, glass curtain walls typically use aluminum alloy or other metals as the framework, with glass being enclosed and shaped to form a unique building envelope wall system.

Currently, the most common types of curtain wall structural systems are proportional curtain walls made of double-layer and single-layer glass materials. These curtain walls not only exhibit superior overall performance, bringing a novel and aesthetic experience to the exterior walls of building structural systems, but also meet indoor lighting requirements.

II. Technical Key Points for Glass Curtain Wall Construction

In the field of construction engineering, glass curtain walls are widely used on the facades of various buildings due to their unique decorative effects and functionality. However, due to the particularity of their material, glass curtain walls face a series of technical challenges during the construction process. Firstly, glass, as a fragile item, poses potential safety hazards during the breaking process that cannot be ignored. Therefore, selecting appropriate glass materials and ensuring construction safety become the primary tasks during the construction process. At the same time, as glass curtain walls are usually installed on the facades of buildings facing the street, they not only need to withstand the impact of natural factors such as wind loads and rainwater infiltration, but also need to cope with the challenges brought by changes in environmental temperature. Therefore, the construction technology of glass curtain walls not only affects the aesthetics and functionality of the building, but also directly impacts the safety and service life of the building.

In terms of construction, glass curtain walls must meet a series of stringent requirements. To ensure sealing and waterproof performance, flexible gaskets must be installed at the joints between mullions and transoms to eliminate friction noise caused by material deformation. Additionally, insulating gaskets should be installed at the contact points between different metal materials to prevent galvanic corrosion. The joint glue seams between curtain wall glasses and the gaps between the curtain wall surface and the interior and exterior decorations of the building all require flexible materials for caulking treatment to ensure the overall performance and aesthetics of the curtain wall. Simultaneously, the deformation joint structure of the unit panels must adapt to the requirements of the main building to ensure the stability and durability of the curtain wall under various environmental conditions.

In addition, the fireproofing and lightning protection design of glass curtain walls are crucial aspects that cannot be overlooked during the construction process. It is imperative to adhere to relevant building codes and standards to ensure that the glass curtain walls not only exhibit their decorative effects but also provide effective safety guarantees. The implementation of these technical measures can significantly enhance the quality and safety of glass curtain wall construction, thereby meeting the multifaceted demands of modern architecture for aesthetics, practicality, and safety.

In the fire protection design of glass curtain walls, key measures include establishing horizontal fire zones along each floor, and simultaneously filling the gaps between window walls, window sill walls, partition walls, and around window openings with non-combustible materials. To facilitate the installation of fireproof layers, the horizontal frames of the glass curtain wall should be positioned within the floor elevation range. Furthermore, when dividing the curtain wall, it is important to ensure that the same piece of glass does not span two floors to prevent the glass from shattering in a fire, thereby preventing the spread of flames from one fire zone to another.

In terms of lightning protection design, the glass curtain wall needs to be reliably connected to the main structure's lightning protection system. Specific connection methods may include connecting embedded parts to downlead reinforcement, connecting to the building's grading ring, or setting up a separate grounding downlead. It is important to note that the measured grounding resistance value should not exceed 10Ω.

In addition, the glass curtain wall must undergo rigorous verification to ensure its sufficient load-bearing capacity, stiffness, stability, and displacement capacity relative to the main structure. The verification content typically includes the calculation of the load that the glass curtain wall bears, the verification of the load-bearing capacity and deflection of structural components, the selection and verification of glass materials, the verification of the anchoring load-bearing capacity of connectors and the main structure, as well as the verification of the ultimate load-bearing capacity of structural adhesives.

III. Key points of construction technology for glass curtain walls on the facade of building exterior walls

During the construction of glass curtain walls on the facades of building exteriors, a series of key technical points should be adhered to ensure construction quality and safety. These points include:

(I) Technical points of surveying and setting out

The installation and measurement of the glass curtain wall must closely coordinate with the measurement of the main structure to determine the reference axis of the curtain wall. Key points should be identified on key layers, and a level gauge should be used for precise horizontal line setting-out. The setting-out measurement should comprehensively cover the elevation dimensions of each layer, the height of each floor, the total height, and the relevant dimensions of the external structure of the main body to ensure the accuracy of the curtain wall installation.

(II) Technical key points for embedded part processing

Embedded parts play a crucial role in the connection between the curtain wall structure and the main concrete structure. Therefore, iron parts need to be pre-embedded in each layer of cast-in-place concrete slabs or beams of the main structure. Angle steel connectors are fixed to the embedded parts through welding, and then connected to the vertical joists using bolts. At the same time, during the connection process between the "T" slot embedded parts and the angle steel connectors, attention should also be paid to the correct installation and calibration of fasteners.

(III) Technical key points of cladding installation

During the installation of joists, it is essential to ensure that all node connectors are securely connected, and that they are aligned horizontally and vertically in accordance with the design specifications. The main joist should be installed layer by layer from the bottom up, and securely connected to the floor slab through connecting fasteners. To prevent deformation of the joist due to temperature changes, expansion gaps of appropriate width should be reserved at the joints. After installation, a theodolite should be used for verticality correction, and all connecting bolts, nuts, and washers of the vertical joists should be tightened and welded securely.

(IV) Technical points of fire prevention and lightning protection

During the construction of glass curtain walls, special attention must be paid to safety measures for fire prevention and lightning protection. According to relevant specifications, strict fireproof layers should be installed, and it is essential to ensure that the glass curtain wall is reliably connected to the lightning protection system of the main structure, in order to safeguard the safety performance of the building.

During the construction of glass curtain walls, safety measures for fire prevention and lightning protection are crucial. To ensure the sealing between floors, we embed fireproof soundproof cotton on galvanized steel plates, cover the inside of the steel plates with rubber sealing strips, and firmly nail the steel plates to the concrete floor with expansion bolts. At the joints between the steel plates and the joists, we carefully apply asphalt sealing tape and lay it flat to ensure the sealing effect.

In terms of lightning protection, we have established a lightning protection system for the curtain wall itself, which is reliably connected to the main structure. For non-welding parts of the curtain wall, we conduct electrical connections according to design requirements to form a conductive path. To prevent electrochemical reaction corrosion of the frame materials, we use the method of adding transition shims to handle contact surfaces of different materials.

Next comes the installation of the glass panels. We pre-sort the glass and transport it to the designated location, cleaning the dirt inside the frame. We insert rubber positioning blocks into the lower frame and embed rubber strips on the inside to ensure that the glass is correctly inserted into the groove frame, with consistent depth all around. At the same time, we have also installed aluminum alloy top plates and taken waterproof measures to prevent rainwater from entering through the gap between the curtain wall and the parapet.

Lastly, we move on to the gluing process. We use a professional cleaning agent to wipe down the aluminum profiles and glass surfaces where the glue will be applied, ensuring they are clean and dry. We apply adhesive tape along the gluing area to prevent contamination of the glass surface. When using the gluing machine, we maintain a steady speed to avoid creating bubbles. Once the glue is applied, we use a professional scraping tool to press and smooth out the glue seam.

Glass curtain walls, as an important enclosure structure for the facades of buildings, not only support the functional use of the buildings but also constitute a gem of decorative art. Their design cleverly integrates practicality with aesthetic value, enhancing the functionality of the buildings while imparting a unique visual aesthetic.

With the rapid development of urbanization, the application of glass curtain walls has become increasingly widespread, and the architectural effects have become more outstanding. However, problems have gradually emerged during the construction process. To ensure the construction quality and building safety of glass curtain walls, construction companies must be proficient in mastering the correct construction techniques and standardized operating procedures.

Strictly follow the specifications

During the construction of glass curtain walls, it is imperative to strictly adhere to relevant construction specifications and technical standards. This encompasses meticulous control over the construction process, rigorous inspection of material quality, and comprehensive assurance of construction safety. Only by ensuring that every aspect meets the regulatory requirements can a safe and aesthetically pleasing glass curtain wall be constructed.

During the construction of glass curtain walls, adhering to specifications is crucial. This encompasses every detail, from material selection to construction procedures, ensuring that each aspect meets the dual standards of safety and aesthetics. Only in this way can we create high-quality, durable glass curtain walls that add a beautiful touch to buildings.