①Hinged truss: A structure before the emergence of the portal frame. Due to the shortage of steel at the time, concrete columns were used, and only truss steel structures were used on the roof. Moreover, it was a truss-type lattice structure, which reduced the amount of steel. The construction was definitely more troublesome than the solid-belly type, but labor costs were also lower at the time. Now they have been basically eliminated, and those that are still used are some severely corrosive factory buildings that use concrete and solid-web roof trusses.
Advantages: simple calculation, clear stress, strong adaptability to pile foundation settlement, and easy installation.
Disadvantages: The bending moment of the lower column is large, and the lateral stiffness of the factory building is poor.
② Rigid frame frame: suitable for single-span factory buildings with small pile foundation settlement differences and high lateral stiffness requirements.
Advantages: It is beneficial to reduce the bending moment of the lower column and enhance the lateral stiffness of the factory building. The stiffness is large, the cross section of the lower column can also be made smaller, and the utilization rate of the factory building area is also high.
Disadvantages: The stress on the roof trusses is complicated, the connection structure is cumbersome, and it is sensitive to pile foundation settlement. Compared with hinged racks, construction is inconvenient. The steel structures are all prefabricated. If one side settles a little during construction, it will not be easy to connect, which can easily cause assembly stress (load caused by support settlement).
③Upper rigid frame and lower cantilever frame: used less.
