Analysis of Installation Technology for Steel Supports-Frequently asked questions-Tianjin Zhiyi Metal Products Co., Ltd.

1. When installing the steel support, the measuring group sets out the support position, processes the steel purlin outside the site, and welds the support bracket steel pad with the dropout plate on the steel purlin. According to the width of the foundation pit, the group forms a subway steel support with one end fixed and one end movable. The length is temporarily determined based on the section width, and steel wedges are used for fine adjustment. Four reinforced plates are symmetrically welded on the grid column along the direction of the line, Weld on the lattice column according to the support position along the direction of the line, chisel the surface of the retaining pile structure within the support range as the support surface of the steel waist beam, and install the bracket.

Install steel purlins and support bracket steel pads, fill the gap between the steel waist beam and the retaining pile with C20 concrete, use a 25T crane or tower crane to lift the assembled steel support onto the steel bracket, so that the wider position of the movable end is supported on the steel pad, and pad a hardwood wedge below the steel support. Then, use a limit plate and a limit reinforcement to fix the steel support. Use two hydraulic jacks to symmetrically apply pre-stress along both sides of the support, The applied prestress is 0.6 times the design axial force, and after the pressure gauge significantly decays, steel wedges are used to lock the steel support.

2. The steel support construction unit can select the segmented length based on the feeding length and construction process requirements, and assemble it on site according to the width of the foundation pit. The deviation of the centerline after installation should not be greater than 1/1000 and less than 20mm, and the installation period of the steel support should not exceed 12H. The construction unit may adopt other forms of steel support movable and fixed ends based on existing equipment and processing experience, but they must meet the stress requirements. Install a pre compression jack on one side of the steel pipe (the construction unit designs and manufactures the jack according to the pre applied axial force design value and the selected jack) to pre apply axial force to its support. The specific pre applied axial force value is shown in the relevant drawings.

3. When constructing supports of the same height within the same wall section, all fixed ends must be arranged and installed at the same time. After the support installation is completed, the connection and resistance of the nodes should be checked in a timely manner. After meeting the requirements, a jack should be used to pre apply axial force to prevent damage to the wall section products due to uneven force on the same wall section. The pre-stressed steel purlins are loaded in two stages, each with a 50% pre-stressed force. Within 12 hours after applying pre-stressed force, the loss of pre applied axial force and the horizontal displacement of the wall are observed, and the pre applied axial force is re applied to the design value.

Analysis of Installation Technology for Steel Supports

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