ATTEN: Manager Liu
ADD: Longhua Development Zone, Jing County, Hengshui City, Hebei Province
2.3 The support system portal frame structure system belongs to the plane structure system. In the transverse direction (i.e. the direction of the pitch), the plane main rigid frame can bear both vertical and transverse loads. In the longitudinal direction, the vertical horizontal force is borne by the support, which makes the whole rigid frame into a building with spatial stiffness. Supporting system generally uses 0.5-15Kg/m2 steel, which only accounts for a small part of the whole structure, but its role is very important, so we must pay attention to it in design. When supporting and utilizing the garden steel, it is generally required to set one piece between 30 and 40 meters, and the maximum is more than 60 meters. The position of support between pillars should be the same as that between pillars of roof support, so that two rigid frames can directly form a stable space system, which can make the route of vertical wind load to the foundation more direct, and also make the classification of frame according to whether there are supporting holes and connecting plates easier, and facilitate the manufacture and installation. When the span is large or the wind load is large, there are several more supporting systems. The steel consumption of this part is very small, but it is very beneficial to the whole structure.
In addition, in multi-span structures, the support between columns is propagated to share part of the vertical and horizontal loads transmitted to the foundation, so that the truss system composed of roof support has the effect of intermediate support, which greatly reduces the traditional chess mode of calculating the support of support rods, regardless of how many supports the whole building has, all of them are assumed according to the first support system on the windward side. Wind load on windward side. Although the calculation of the longitudinal tie rod between supports is simplified and avoided, the algorithm is obviously too conservative. According to the wind load and support system transmission mode in reference , the longitudinal tie bar must transmit the force, because the internal force of the support system is calculated according to the traditional simplified calculation mode than that of the portal frame lightweight building. The second simplified calculation method is to add the wind loads on the two ends of the gables and divide them by the number of supporting paths to obtain the loads on each reclamation surface truss horizontal support and pillar support. According to the accurate calculation and analysis of this method in document 3, the calculation of the cable-stayed rod is accurate, and the calculation of the internal force of the straight-pressed rod is too small. The more the number of supporting passages, the greater the error.
In order to ensure the safety of the whole supporting system, it is suggested that the internal force of the straight compression bar should be designed according to the accurate calculation. In the light steel structure support design, usually the cross bar is made of tensioned round steel, and the diameter of round steel should not exceed 30 mm, because the pre-tension force is too large after 30 mm, the angle steel support should be considered at this time. In the traditional steel structure, the long longitudinal tie bar in the roof system is made of special national steel pipe or double angle steel beautifully, and the amount of steel used is large. In light steel structures, brown bars can be fully utilized as vertical tie bars and straight bars in horizontal support of measuring plane. If the force is large, double purlin can be considered. Compared with the traditional design, this method can greatly save 3.1 steel brown strips and wall beams, mainly using Z-type or C-type cold-formed thin-walled steel. In general, in addition to the window frame and door frame, the use of C-type wall beams is preferred in other cases. By comparing these two types of components, the following conclusions can be drawn. On the eccentricity between the center of radius and the center of shape of 3.11C type component, while the shear center of B type component coincides with the center of shape (as shown in Fig. a), the summer tilting moment of B type component under gravity load is larger than that of C type component.