Multi span greenhouse is one of the most important types of greenhouse in mechanized facility agricultural production. Due to the subsidies in previous years, a large number of multi span greenhouses have been built everywhere, but they will face many problems in use and management. Today, I'd like to share some notes on design and construction management.

1、 Consultation and decision-making of early construction

First, prior to the commencement of construction, preliminary consultation is essential, including feasibility study, investment evaluation and analysis, technology and practice, etc. The technical consultation of multi span greenhouse includes: cultivation or production mode, construction and operation scheme and design scheme. After technical consultation, the type, scale, structural form, equipment selection and design of heating, lighting, ventilation and cooling of the greenhouse will be determined. Some people will think that the intelligent multi span greenhouse is a widely applicable greenhouse. In fact, it is not. The greenhouse design varies greatly according to different planting needs, such as the environmental parameters required for planting orchids, seedlings or vegetables.

2、 Design of greenhouse

At present, there are no national mandatory specifications for the design of multi span greenhouse, only industrial specifications. Therefore, it is necessary to cooperate with the Design Institute for greenhouse design and development. If it is designed only by the Design Institute, some structural fitting specifications of the industry will be ignored. If it is designed only by the greenhouse company, some structural strength load specifications will be ignored.

Secondly, the construction unit should also understand some industry standards. For example, the greenhouse can maintain normal operation through the operation of supporting facilities under the outdoor temperature of - 15 ~ 40 ℃, and the average light transmittance of the greenhouse should reach more than 70%; All steel structures must be hot-dip galvanized for surface corrosion protection; The greenhouse maintenance structure shall meet the water tightness requirements; The service life of the main structure of the greenhouse shall not be less than 15 years.

3、 Design and construction of greenhouse Foundation

At the beginning of foundation, surveying and setting out is a key link. Because the superstructure components of the greenhouse are prefabricated parts, the accuracy of the plane position and elevation of the embedded parts on the foundation top will directly affect the quality of component installation. If it is not handled well, it will even cause rework. The greenhouse generally covers a large area, and the number and density of internal columns are much larger than those of other buildings. In order to improve the wind resistance of the greenhouse, an independent concrete foundation is adopted under the column, and the control of foundation top elevation is very important. Generally, it is required that all foundation top elevations should be measured and positioned continuously at one time, the supervisor's review should also be completed at one time, and detailed measurement records should be made at the same time. In this way, the error caused by instrument calibration and calculation can be avoided to the greatest extent.

4、 Main body installation precautions

1. Pay attention to on-site protection when materials enter the site to avoid semi-finished products from being damaged.

2. Strictly follow the construction sequence. The installation steps of superstructure are generally as follows: column (cable-stayed installation) - lattice frame - rain gutter - Roof Truss - purlin and ridge - internal and external sunshade transmission system - skylight - top PC board - facade PC board and side windows - curtain and power distribution system - greenhouse door - external sunshade Network - internal sunshade Network - wet curtain, fan - power distribution system - water heating system.

3. Avoid on-site welding as much as possible, because multi span greenhouses are industry standard parts, and the hot-dip galvanized finished products made by the factory have high anti-corrosion and anti rust ability.

5、 Acceptance of completion data

Because there are many materials and accessories in the multi span greenhouse, and the warranty period of different materials is different. Therefore, party a must keep all kinds of material certificates and quality assurance certificates. At the same time, the general construction projects of multi span greenhouses need government subsidies for acceptance.