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SDS tunnel fan pull-out bearing capacity testing

Tunnel fans are usually hung on the top or both sides of the tunnel to replace the exhaust gas of vehicles in the tunnel. The tunnel fan is very heavy and installed at the top of the tunnel, so there is a certain safety hazard. It must undergo a pull-out test and pass it before it can be used.
The fan pull-out test is conducted by applying different self weight pressures to test the load-bearing capacity of various components supporting the fan. During the testing process, third-party inspectors conducted detailed tests on the self weight pressure of the fan according to the testing standards. Firstly, a jack was placed in the center position at the bottom of the fan bracket, which was reinforced with steel plates. A steel plate capable of bearing the test pressure was manually placed above the jack to apply the load. The vertical tensile force borne by the embedded parts and bracket was the reading on the pull-out instrument display screen. The set inspection load was divided into 10 levels, and each level was held for 1 minute until it reached the inspection load, and held for 2 minutes. During the holding period, the fan hanger was checked for permanent deformation, weld cracking, loosening of the embedded steel plate, and cracking of the surrounding concrete.
The supporting structure of a jet fan is generally composed of a fan base and embedded parts embedded in the secondary lining. According to the requirements of JTGT D70-2-02-2014 "Design Rules for Ventilation of Highway Tunnels", the jet fan should be installed 15cm~20cm outside the building limit, and the fan axis should be parallel to the tunnel axis. The setting method should be fixed or suspended, and the structural bearing capacity of the supporting fan should not be less than 15 times the actual static load of the fan. Before installing the fan, a load test of the supporting structure should be conducted.

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