In cast-in-place concrete construction, formwork fastening systems are the “backbone” to ensure the flatness, firmness and waterproof performance of the concrete structure. The quality of formwork fasteners directly affects the construction progress, project quality and even construction safety. Many contractors and purchasers often face confusion when selecting formwork fasteners: how to distinguish high-quality products from inferior ones? What accessories are included in a complete formwork fastening system to meet the needs of different construction scenarios? This article will give a detailed explanation to help you make rational choices and improve construction efficiency.
First of all, we need to clarify the core criteria for selecting high-quality formwork fasteners. For construction projects, “stability, durability, convenience and cost-effectiveness” are the four key points that cannot be ignored. Each criterion corresponds to specific selection details, which can help you avoid detours in procurement.
The first is material selection, which is the foundation of product quality. High-quality formwork fasteners are mostly made of high-strength steel such as Q235 and Q355. This kind of steel has excellent bearing capacity, toughness and wear resistance, which can withstand the lateral pressure generated during concrete pouring without deformation or fracture. When selecting, we can ask the supplier to provide relevant material inspection reports to confirm that the steel meets the national or industry standards. It should be noted that some inferior products will use low-quality ordinary steel to reduce costs, which is easy to bend, break or rust during use, leading to formwork loosening, grout leakage and other problems, and even requiring rework, which increases construction costs invisibly. In addition, for fasteners used in waterproof scenarios such as basements and pools, attention should also be paid to their anti-corrosion performance. Products treated with hot-dip galvanizing or color spraying have better anti-rust and anti-corrosion effects, can adapt to harsh construction environments, and extend the service life of the products, realizing reusable use and further reducing material waste.
The second is process quality, which determines the stability and service life of the product. High-quality formwork fasteners need to go through strict processing procedures such as precision forging, stamping, welding and surface treatment. For example, beam clamps and square column clamps need to be formed by integral forging or precise welding, ensuring that there is no welding slag, crack or looseness at the welding joint, and the structure is firm; water-stop tie rods need to be equipped with integral water-stop plates, and the connection between the water-stop plate and the screw rod is tight without gaps, so as to effectively block water seepage. When selecting, we can observe the appearance of the product: the surface of high-quality products is smooth, without burrs, unevenness and other defects; the size is accurate, which can be perfectly matched with other accessories such as tie rods and backers; the thread of the screw rod is clear and smooth, which is convenient for disassembly and assembly, and not easy to slip. On the contrary, inferior products have rough processing, inaccurate size, easy thread slipping and welding joint detachment, which cannot guarantee the clamping effect.
The third is adaptability and convenience. Different construction scenarios (such as high-rise buildings, basements, beams, columns, walls, etc.) have different requirements for formwork fasteners. High-quality fasteners usually have good adaptability and adjustability. For example, the adjustable range of beam clamps and square column clamps can cover different sizes of beams and columns, meeting the needs of various construction specifications; the three-stage water-stop tie rod adopts a detachable design, and the outer section can be reused after construction, which is not only convenient for disassembly and assembly, but also saves steel materials and reduces construction costs. In addition, the weight and operation convenience of the product should also be considered. Lightweight and easy-to-operate fasteners (such as formwork quick clamps) can reduce the labor intensity of workers, improve installation efficiency, and shorten the construction period.
The fourth is cost-effectiveness, which does not mean choosing the cheapest product, but pursuing the best “cost-performance ratio”. High-quality formwork fasteners may have a slightly higher initial procurement cost, but they have the advantages of long service life, reusability, stable performance and low failure rate, which can avoid the additional costs caused by product damage, rework and other problems. On the contrary, although the price of inferior products is low, they are easy to damage, have a short service life and high replacement frequency, and may even affect the project progress and quality, resulting in greater losses. Therefore, when selecting, we should comprehensively consider the procurement cost, service life, reuse rate and other factors, and choose products with stable quality and reasonable price.
After clarifying the selection criteria, we also need to understand what accessories are included in a complete formwork fastening system. A set of standardized formwork fastening system is not a single product, but a combination of multiple accessories, which cooperate with each other to achieve the effect of formwork fixing and waterproofing. According to the functional division, the system accessories mainly include the following categories:
The first category is core fastening components, which are the core of the entire system and responsible for the main clamping and fixing functions. Common products include water-stop tie rods (three-stage water-stop tie rods are the most widely used), beam clamps, square column clamps, butterfly clips, formwork U-clips, formwork quick clamps, etc. These products are directly connected with formwork, backers and other components to ensure the stability of the formwork during concrete pouring. For example, water-stop tie rods are used to fix the formwork of waterproof walls and prevent water seepage; square column clamps are used for the reinforcement of square column formwork, ensuring that the column body is straight and free of deformation; butterfly clips are used with tie rods and backers to disperse stress and avoid local bulging of the formwork.
The second category is supporting connecting accessories, which are used to connect the core fastening components with each other, ensuring the integrity and stability of the entire system. Common products include special connecting nuts, plastic plugs, wing nuts (mountain-type cards), (wall tie rods), adjusting screws, etc. These accessories play a “link” role. For example, wing nuts are used with water-stop tie rods and backers to lock the formwork and adjust the clamping force; plastic plugs are used to block the holes left after the disassembly of water-stop tie rods, ensuring the flatness and waterproof performance of the wall surface; connecting nuts are used to connect the sections of tie rods, extending the length of tie rods to adapt to different wall thicknesses.
The third category is waterproof and anti-seepage accessories, which are mainly used in waterproof construction scenarios such as basements, pools and underground projects to enhance the waterproof effect of the structure. Common products include water-stop gaskets, water-swellable water-stop strips, water-stop plates, etc. These accessories are used with water-stop tie rods and other products to form a “double protection” against water seepage. For example, water-swellable water-stop strips will expand when they encounter water, filling the gaps at the joints, effectively blocking the water seepage channel; water-stop gaskets are installed between the fasteners and the formwork to prevent grout leakage and water seepage.
The fourth category is auxiliary tools and consumables, which are used to assist the installation and disassembly of formwork fasteners, improving construction efficiency. Common products include tension wrenches, crowbars, scaffold couplers, test molds, sealing tape, etc. For example, tension wrenches are used to tighten butterfly clips and nuts, ensuring uniform clamping force; crowbars are used to adjust the position of the formwork, facilitating the installation and disassembly of fasteners; test molds are used to detect the strength of concrete, ensuring the project quality; scaffold couplers are used to fix the scaffold, cooperating with the formwork fastening system to ensure construction safety.
It should be noted that the matching of formwork fastening system accessories is very important. Different core fasteners need to be matched with corresponding connecting accessories and waterproof accessories to exert the best effect. For example, the three-stage water-stop tie rod should be matched with water-stop gaskets, plastic plugs and wing nuts; the square column clamp should be matched with square timber/steel pipe backers and step-by-step tight clamps; the formwork U-clip should be matched with sealing tape to enhance the tightness of the formwork joint. Therefore, when purchasing, it is recommended to choose a supplier that can provide one-stop supply services, so as to ensure the matching of products, avoid the problem of incompatible accessories, and simplify the procurement process.
In summary, selecting high-quality formwork fasteners requires comprehensive consideration of material, process, adaptability and cost-effectiveness, and avoiding the mistake of “only pursuing low price and ignoring quality”. A complete formwork fastening system is composed of core fastening components, supporting connecting accessories, waterproof and anti-seepage accessories, and auxiliary tools. Only by selecting suitable products and matching corresponding accessories according to the construction scenario can we ensure the project quality, improve construction efficiency and reduce comprehensive construction costs.
With the continuous upgrading of the construction industry, the formwork fastening system is also developing in the direction of modularization, standardization and intelligence. Choosing a professional and reliable supplier and a scientific and reasonable formwork fastening solution will become an important guarantee for the high-quality development of construction projects.
