Accurate fabrication size of steel structure is the basis and premise to ensure accurate overall structural size and smooth installation of steel structure workshop. Therefore, it is necessary to accurately grasp the straightness and twist of steel columns, the distance between columns and beam connecting holes and column bottom plates, the machining accuracy of connecting holes themselves, the straightness of roof beams and the machining accuracy of column and beam connecting plates, the position dimensions of tie bars or supporting connecting plates on beams and columns relative to beams and columns, and the position dimensions of purlin plates.

At present, the central column of steel structure workshop is assembled by purchased H-beam or plate. If it is made of ready-made H-beam, the manufacturing accuracy of the column is easy to control. If it is assembled from plates, attention should be paid to the shaping of steel columns after assembly and welding to ensure the straightness of steel columns and prevent deformation. Roof beams are mostly herringbone structures, which are often assembled by 2 or 4 beams. Roof beams are generally assembled by manufacturers with plates, and the webs of beams are often irregular quadrangles. Manufacturers with strong technical ability can accurately grasp the layout and blanking of web plates, while manufacturers with weak technical ability sometimes have deviations in the layout size of web plates. Because the shape and size of the roof beam are related to the tightness of the connection between the beam and the column, the size of the web directly affects the shape and size of the beam, so it is particularly important. In the design of general steel structure factory buildings, there is often a certain requirement for arching the roof beam, the purpose of which is to offset the downward deflection of the beam due to the load of itself and the roof after the whole installation, so as to achieve the installation size. The height of the arch is determined by the design.

In order to ensure the camber, it is necessary to adjust the shape and size of the top beam. From this point of view, it is much more difficult to make beams than columns. When we check on site, we will focus on the external dimensions of the beam and the connecting plate at the beam end, in order to ensure the overall effect after installation and the tightness between the beam and the column. We found that after installation, there was a wedge gap between the beam and the column. At this point, the large hexagon-head bolt has lost the most important function proposed in the original design, only plays a supporting role, and there is no friction between the beam and the column at all. In order to eliminate this hidden danger, we later added shear keys to each column near the lower side of the beam connecting plate to improve the supporting capacity of the roof system, which proved to be very effective in practice.

In order to avoid and reduce the deformation of columns, beams, tie rods and other connectors during transportation, transportation companies are required to add more support points in the whole length range when binding components, and the components should be padded as much as possible, and the peripheral binding should be firm to minimize the deformation of components caused by vibration or heavy pressure during transportation; Two-point crane should be used for loading and unloading. If the component is too long, you can use poles and increase the lifting points appropriately. When the components are stacked at the installation site, the number of stacked layers should be reduced as far as possible, generally no more than 3 layers, and at the same time, the support points should be appropriately increased to prevent the components from being deformed by compression.

Steel structure

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Hai Ruo steel structure

Second, the control of steel structure installation

Before the installation of steel structure workshop, we should do all the preliminary work well. For example, before hoisting, the installer should retest the component, and hoisting can only be carried out on the premise that the component is not deformed and the installation size is correct. In addition, on the premise of confirming that the strength of foundation concrete meets the specification requirements, the installer should also test the embedded bolts or cups of steel column foundation. If the position and elevation dimension of the foundation are deviated, it is necessary to record this part so as to adjust the position of the steel column.

In order to improve the installation accuracy of the whole steel structure, it is best to choose the workshop part with inter-column support, tie rod and roof support for installation. After this part of the steel column is hoisted, the axis and elevation of the steel column should be re-measured. After correction, the steel column is temporarily stabilized with cable wind rope, and then the inter-column support, top beam and tie rod between beams are installed. This is the so-called rough loading. Before the top beam is installed, it should be assembled on the ground first, and then hoisted after the measurement is qualified.

High strength bolts should be tightened first. During the tightening process, the axis of the steel column should be dynamically tracked. If the axis changes beyond the allowable value, it should be adjusted immediately. The whole tightening process should be carried out from the beam-column joint to the bearing and tie rod joint, and both ends of the same part should be carried out symmetrically at the same time to reduce the accumulated error on one side. Only in this way can the steel column be installed correctly. In this process, if it is found that the installed part does not match the installed part, the installed part cannot be adjusted, but the installed part can be adjusted or other remedial measures can be taken. For example, the steel beam and the steel column do not match, and the steel column cannot be adjusted, so the steel beam can only be adjusted. In the whole installation process of bent frame, the correct installation of steel column is a necessary condition for all other correct installation.

During the installation of steel structure workshop, each independent bending part should form a stable structure as soon as possible. Through the above method, several other parts can be installed separately in turn, so that the whole factory building has a stable interval bent structure, so that the accumulated errors generated in the installation process of the whole factory building can be dispersed to all parts, and the deformation, falling off or even overturning of the installed steel members due to natural conditions can also be avoided.

All temporary fixing bolt holes that need to be welded on site should be designed as long holes, which is convenient for installation and adjustment and more conducive to ensuring the overall installation accuracy. Single-side connecting holes of sub-components such as purlins should also be designed as long holes, and of course, relevant gaskets should be increased accordingly. What needs special attention is that the purlin is installed at high altitude and the board wall is thin. If the purlin is cut and sprayed at high altitude because of the deviation of the installation hole, it will really bring a lot of inconvenience and danger, and it will also affect the appearance. Therefore, it may be more reasonable to design the connecting holes between the two ends of purlins and steel beams and columns into long shapes, or at least to design them unilaterally.

When installing roof steel frame system, sometimes there is a contradiction between roof support and roof purlin installation. If the roof support is installed first, the roof purlin cannot be hoisted; If the roof purlin is installed first, the roof support is not convenient for hoisting. Our usual practice is to hang roof purlins on roof beams in batches and fix them. Purlins in the same span can be divided into three or four batches and must be fixed after stacking. It is very important to let the crane boom extend out of the roof from the gap between each batch of purlins, and then unfold the roof purlins after lifting and fixing the roof support. Considering that the installation of enclosure and main structure is often not the same construction unit, it must be commanded and coordinated by experienced managers. Doing so can not only avoid mutual interference between construction units, but also improve the safety of aerial work.

Finally, talk about the installation of color plates. Before the installation of the color plate, the standard dimensions of the length and width of the color plate should be determined by measurement. The purpose is to ensure that the upper edge of the color plate can be placed on the side of the purlin, and at the same time ensure that the overlapping length of the upper and lower color plates is not less than 1.20mm to avoid water seepage when it rains. Be sure to straighten the purlin before installing the wall color plate. In this way, the self-tapping nails for installing color plates can be neat, straight and beautiful. It is much easier to install roof color plates and straighten purlins than to install walls. It should be emphasized that the buckle must be firm. If self-tapping screws are used, the sealing ring must be brought, so I won't go into details here.

There are many installation methods of steel structure workshop. As a manager, we should constantly summarize them and pay attention to the accumulation of work experience. In this way, when we continue to install steel structure workshops in the future, we can not only improve the installation accuracy and reduce the amount of rework, but also improve the safety of aerial work.