1. What Are Shoring Props?
Shoring Props, also known as props, steel shores, or adjustable shoring props, are key vertical load-bearing components in the formwork support system of construction projects. They are used to bear the vertical loads during concrete pouring and construction, transferring them to the ground or lower structures to ensure that concrete components such as beams, slabs, and columns do not deform or sink before their strength meets the design requirements. It is mainly composed of an outer tube, inner tube, adjusting nut, base, top plate, and locking device. The height adaptation is achieved by adjusting the expansion and contraction of the inner tube, meeting the construction needs of different floor heights and loads.
2. Core Functions and Application Significance
1). Bear Vertical Loads and Ensure Structural Safety
The core function of Shoring Props is to bear vertical loads such as concrete self-weight, formwork weight, construction personnel, and material equipment weight. Their bearing capacity directly determines the safety of the support system. The rated bearing capacity of ordinary carbon steel shoring props is ≥15kN, and heavy-duty props can reach 50-100kN, which can effectively resist the vertical pressure of different grades of concrete from C30 to C80. In the floor construction of a 32-story office building, spiral shoring props with a rated bearing capacity of 30kN were used with a spacing of 1.2m×1.2m. During concrete pouring, the shoring props had no settlement or deformation, and the floor flatness deviation was ≤3mm, meeting the requirements of Code for Acceptance of Construction Quality of Concrete Structures (GB 50204-2015), avoiding the risk of structural collapse caused by support failure.
2). Precise Height Adjustment to Adapt to Multi-Scenario Needs
Shoring Props achieve fine height adjustment through adjusting nuts or hydraulic devices. The adjustment range is usually 1.0-3.5m (special customization can reach 5.0m), and the adjustment accuracy is ≤5mm, which can accurately adapt to different floor heights (2.8m, 3.0m, 3.3m, etc.) and structural height deviations. In the construction of basement high-low span structures, the shoring props can keep the formwork support surface horizontal through height adjustment, ensuring the forming accuracy of concrete components; in bridge box girder pouring, the formwork elevation deviation can be corrected by fine-tuning the top plate height, ensuring the bridge alignment meets the design requirements. In the approach bridge construction of a cross-sea bridge, hydraulic shoring props were used, and through a synchronous adjustment system, the height deviation of 120 shoring props was controlled within 2mm, ensuring the quality of box girder pouring.
3). Improve Construction Efficiency and Shorten Construction Period
Shoring Props adopt a modular design with light single weight (20-30kg for carbon steel type, 12-18kg for aluminum alloy type). No large lifting equipment is required, and 2 workers can complete installation and disassembly with an installation speed of 30-40 pieces/hour, which is 4-6 times that of traditional wood props (5-8 pieces/hour). Taking 1000㎡ floor construction as an example, the installation of shoring props only takes 25-30 hours, saving 80-100 hours compared with wood props and shortening the construction period by 4-5 days. In addition, the shoring props can be folded and stacked after disassembly, facilitating transportation and storage, reducing the site occupation cost; the core components can be reused 150-200 times with low maintenance costs, further improving the construction cost-effectiveness.
4). Enhance Support System Stability and Reduce Safety Risks
The outer tube and inner tube of Shoring Props are made of seamless steel pipes or high-frequency welded pipes, combined with reinforcement rib design, which has excellent lateral bending resistance and instability resistance. The base plate is made of thickened steel plate (thickness ≥8mm), increasing the contact area with the ground, reducing the pressure per unit area (≤0.3MPa), and avoiding the shoring props sinking into the ground; the top plate is equipped with anti-slip rubber pads to enhance the friction with the formwork and prevent slipping. In the full-space support construction of a basement, heavy-duty shoring props with a spacing of 1.0m×1.0m were used, combined with horizontal tie rods to form an overall support system. After load testing, the maximum settlement was ≤2mm, with no shaking or instability, effectively reducing the safety risk of high-altitude operations.
3. Material and Process Standards
Carbon Steel Material: Outer tube and inner tube are made of Q235/Q355 low-carbon steel or 40Cr alloy steel, complying with GB/T 700-2006 standard, with tensile strength ≥370MPa and yield strength ≥235MPa;
Aluminum Alloy Material: 6061-T6 aluminum alloy is used, complying with GB/T 3190-2022 standard, with tensile strength ≥260MPa and yield strength ≥240MPa, and strong corrosion resistance;
Processing Technology: Steel pipes adopt seamless or high-frequency welding technology, with weld height ≥3mm, no pores or cracks, qualified by flaw detection; threads adopt rolling technology, with precision up to 6H grade, and smooth adjustment without jamming;
Anti-Corrosion Treatment: The surface of carbon steel shoring props is hot-dip galvanized (zinc layer thickness ≥85μm) or electrostatically sprayed, with salt spray corrosion resistance ≥500 hours; aluminum alloy shoring props adopt anodization treatment (oxide film ≥15μm) with excellent corrosion resistance;
Safety Devices: Equipped with dual locking devices (adjusting nut + locking pin) to prevent loosening during use; hydraulic shoring props are equipped with pressure overload protection valves to avoid overloading.