Roof mounting of photovoltaic racking

When installing photovoltaic racks on flat roofs, it is necessary to make the foundation pre-embedded parts firmly welded or connected to the steel bars of the main roof structure. If welding and connection cannot be carried out due to structural limitations, a concrete block counterweight foundation should be adopted to increase the adhesion between the foundation and the roof, and it can be further fixed by using the wire tensioning method or the bracket extension and fixing method introduced earlier. Especially in the southeast coastal typhoon prone areas, the counterweight foundation is directly related to the safety of the photovoltaic power generation system, affecting the photovoltaic square array of typhoon resistance, there is a security risk of being overturned by the gale, so the design and construction of the counterweight block foundation should be further increased load bearing, and further reinforcement. In addition, the counterweight foundation with insufficient load bearing has the risk of being locally moved, which may lead to deformation of the bracket and damage to the components.

When installing a PV square array on a colour steel roof, the PV modules can be laid and installed parallel to the slope of the roof surface, or they can be designed to be arranged at a certain inclination. The module bracket can be connected to the roof load-bearing structure through different connectors and fasteners. At present, the colour steel plate roof is mostly in the form of slope, the common slope is 5% and 10%, the roof plate is pressure steel plate or pressure sandwich panel, the lower part is sandalwood, sandalwood is built on the support structure such as portal triangular steel frame. The main forms of common colour steel plate roof are upright lock edge type, angle chi type, bayonet type, open nail type and so on.
When installing photovoltaic module square array on the roof of colour steel plate, its installation method has a direct relationship with the steel frame structure supporting the roof of colour steel plate, the roof rack structure, the strength and quantity of sandalwood strips and the form of the roof panel, etc. For the different load-bearing structure of the roof of colour steel plate, different installation methods will be adopted.
(1) The load-bearing strength of steel frame, roof frame, sandalwood strip and rigid strength of roof plate can meet the installation requirements.
This situation is the most reasonable installation conditions, and the PV bracket and square array can be installed directly. Use connectors to connect the PV bracket to the roof plate, as close as possible to the position of the sandalwood bar for fixing.
(2) The load-bearing strength of the steel frame, roof bracket and sandalwood bar can meet the installation requirements, but the rigid strength of the roof plate is small and the deformation is large.
This type of colour steel roof is mainly used in simple workshop, carport, public marquee, farm and some other less demanding places. The photovoltaic bracket can be directly connected with the roof plate at the sandalwood bar directly by using the connectors, or the connectors can be connected with the sandalwood bar by penetrating the roof plate.
(3) Only the steel frame and the roof support can meet the installation requirements, and the carrying capacity of the sandals and the roof plate is small.
In this case, only the connector can be directly connected to the steel frame or roof support, the specific connection and installation method is also used to connect the connector through the roof plate. Another way is to cut the roof plate at the location of the fixed bracket and weld it to the steel frame or roof bracket by using angles and channels as struts.
Among the several ways mentioned above, any connection involving penetration of the roof must come with a waterproof gasket or be treated with a sealing structural adhesive to ensure waterproof capability. If the strength of the steel frame, roof bracket, sandalwood strip and roof panel cannot meet the installation requirements, it is not possible to carry out PV square array installation. If it has to be installed, the whole steel structure of the colour steel roof needs to be re-strengthened first.
In the construction process of photovoltaic square array foundation and bracket, it is necessary to eliminate the phenomenon that the bracket foundation is not aligned, the front and rear columns of the bracket are not on a line as well as the cross beams of the component square array are not on a horizontal line, and the phenomenon of arc shape or wave shape appears. Damage to relevant buildings and ancillary facilities should also be avoided as much as possible, and if local damage is caused by necessity due to construction needs, it should be repaired in a timely manner after the construction is completed.