In recent years, due to the characteristics of steel structures, steel structure technology has developed rapidly. A large number of steel structures light steel plants, large-span plants, and high-rise buildings have been built around the world. In particular, the portal frame structure is the most widely used, and the reason is determined by the characteristics of the steel structure itself.
1. Positioning measurement
Based on the design information of the steel structure, the foundation's horizontal elevation, axis, and column spacing were re-tested. The cross lines of the vertical and horizontal axes are marked on the top surface of the foundation as the positioning reference for the installation columns.
In order to eliminate the influence of column length manufacturing errors on the column elevation, before lifting, measure 1m downward from the plane above the ox leg as the theoretical elevation section, and mark it clearly for use as a benchmark for adjusting the column elevation. On the upper surface of the base plate of the pillar, mark the cross line of the vertical and horizontal axis passing through the center of the pillar, and use it as a reference for the installation and positioning of the pillar. During installation, the column and the cross line on the foundation are overlapped. First, use a spirit level to correct the level of the column with the mark at the theoretical level of the column, and then use a pad to solidify and tighten the anchor screws. Then use two theodolites to correct the verticality of the column from the two axis directions, and use double nuts to tighten the bolts when the requirements are met. For a column with a single unstable structure, temporary protection measures can be taken with the help of a wind cable. For columns designed with inter-pillar support, the inter-pillar support can be installed to enhance structural stability.
3. Crane beam installation
Before the crane beam is installed, it should be inspected, and it can only be installed when the deformation does not exceed the limit. After the single piece of crane beam is hoisted in place, it should be bolted to the corbel in time, and the connecting plate between the upper edge of the beam and the column should be adjusted with a spirit level and a theodolite.
4. Roof beam installation
The roof beam should be inspected before the ground is assembled. When the deformation of the component does not exceed the limit, the high-strength bolt connection friction surface is free of debris and other debris, and the friction surface is confirmed to be flat and dry, it can be assembled on the ground. During assembly, oil-free sleepers are used to cushion the components, and both sides of the components are supported by wooden bars to enhance stability. The assembly of the roof beam of a steel structure house takes the space between two columns as a unit, and the unit is to be inspected after splicing:
① the straightness of the beam;
② The distance between bolt holes and other components (such as columns). After the adjustment and inspection meet the requirements, tighten the high-strength bolts.
The installation of roof purlins and wall purlins is performed simultaneously. Before installing the purlins, inspect the deformation of the components, and if there is any excess, treat the surface to remove the oil, sand, etc. on the surface of the components. Take several purlins as a group and hoist them together. After the span is installed, check the incline slope. It is required that the straightness of the purlin is controlled within the allowable deviation range, otherwise, it is adjusted by using connecting bolts (if necessary).