Recently, nanjing snow, rooftop photovoltaic system is collapsing the video circulated widely, video, though only a few seconds, but can see the scene. Photovoltaic power station, together with the factory, by blizzard collapse, abnormal scenes. The roof load problem, again to the attention of the people! Distributed photovoltaic project roof load problem, especially easy to form a larger scale of project of steel structure caigang WaWu surface load problem, become one of the most important concerns in the project development.
That how to anticipation, the bearing capacity of photovoltaic roof in largely determine whether meet the requirements of the photovoltaic project? 1 photovoltaic roof classification according to the time of the load categories: permanent load ( The constant load) And variable load ( Live load) , accidental loading ( Special load or accidental) 。 Photovoltaic (pv) power plant belongs to the new system with constant load. According to the plane of action size classification: uniform load and concentrated load and linear load. According to the direction classification: vertical load and horizontal load. 2 roof load of distributed photovoltaic project involves 1) Weight of roof structure weight of reinforced concrete floor and roof color steel purlin steel weight, weight of roof insulation waterproof materials and roof of every component and equipment (the original Constant load) 。
2) Photovoltaic modules of photovoltaic (pv) power system load, bracket, foundation, cable, and junction box, etc. ( New constant load) 。
3) Wind, rain, snow load for building photovoltaic power station, and lead to the increase of the wind, rain, snow load.
4) The construction load ( The late operational load) During construction, equipment, material of lifting, transportation, construction personnel, construction equipment such as the role of the effect, belongs to the live load. Earthquake does not belong to load, is a kind of role, provisions on earthquake action and checking calculation, see GB50011 - 2010 'code for seismic design of buildings. 3 load forecasting 1) Drawings of simulation through the structure drawings, using software ( Such as MTStool, Richard toolkit is structure, etc. ) The main stress components ( Such as purlin, floor, etc. ) Preliminary calculation. 2) Field actual buildings compared with design drawings, found outside of new design load or late for reconstruction of load change. Outdoor investigation between roof additional equipment, elevator, air conditioning or antenna equipment foundation, fire or ventilation pipes, etc. Indoor survey and large leakage, beam plate column with and without cracking, corrosion and damage, new ceiling artifacts, roof hanging equipment inside, roof open hole, new indoor track cranes, etc. If you want to get reliable load data, should be after on-site investigation, combined with the actual load conditions, structural modeling system of accounting.
Four concrete roof load forecasting 1) The bearing capacity of the reinforced concrete roof of new photovoltaic hair system checking calculation pass rate more than 80%. Suitable to install photovoltaic power generation system structure. Focusing on the problems to build the construction of buildings, old old buildings, there are corners of tofu engineering, reconstruction and secretly situation affects the safety of the original building structure, communication with the owner in the future if there is a roof structure reconstruction plan. 2) Concrete precast slab roof, prestressed double T plate roofing, saddle plate by selecting the appropriate type of installation, such as decrease the installation Angle, avoid the sensitive area, array with guide plate, reduce weight piece of height and weight, etc. , also are installing photovoltaic power station system.
Concrete roof photovoltaic system according to the best Angle of single component installation, the consideration on the concrete weight, about 0. 45 kn /㎡。 5 metal roof load forecasting the bearing capacity of the metal roof of new photovoltaic system checking calculation pass rate is less than 50%. The structure bearing capacity shortage situation is more, need to check carefully before use. Focusing on the problems of formal design unit design, can get the original design drawings, whether to build, ever construction to replace the steel grade, secretly situation affects the safety of the original building structure, the reconstruction and communication with the owners if there is a roof structure reconstruction plan in the future. Caigang watts roof solar photovoltaic system according to the component along the slope roof tile installation, support purline using the fixture on the corrugated metal roofing, about 0. 15 kn /㎡。 Metal roof load fast forecasting method of method one: non-formal, informal construction unit construction design institute of design, no drawings or borrow figure to build factories, basically do not use. Because the structure security is not controllable, brutal hidden danger, the material more shoddy construction. Such as Q235 material substitution Q345 material used. Method 2: about 6 meters span purlin, purlin model is less than 180, purlin accounting easily overrun; Around 8 m span purlin, purlin model is less than 220, purlin accounting easily overrun; Brace between purlin span is greater than 6 m, purlin is only 1 way, purlin accounting lateral instability. Above mainly aimed at the common C or Z purline door type steel structure workshop, the above cases, there are usually increase the photovoltaic power station after load, stress ratio overrun or deflection overrun. The above method is only for your reference during development and in the actual design of the photovoltaic power generation project, the design institute shall on the roof, especially caigang watts roof load calibration, ensure project safety.
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