Project Design and Steel Construction Features

According to soil structure, the foundation pits of 80-100 cm depths will be opened and column stirrups will have the 50×50 size and 50 cm thickness. Concrete will be poured on the foundation pit in the size of 25×25 cm and 60 cm height. Greenhouse surrounding columns will be connected with concrete beam 30 cm aboveground and the middle column foundations will be strengthened. The anchor profiles to be used are 70×70 in size.

Our columns are designed with 80×80 mm size and 2 mm wall thickness, in order to meet the compressive and tensile stresses, and designed with engineering approach against shear force originating from buckling, bending, plant and wind loads. The regions in which the wall thickness per section is increased is placed symmetrically on the midpoints of the lateral surfaces of the profile so as to continue along the profile. The profile corners are rounded; thus, it is 5 times more resistant to buckling and vertical loads than normal column profiles.

Loads were divided into 5 equal sections on the subheads and column tops and the loads were distributed evenly to the greenhouse columns by using 10 mesh materials. The cross ties  descending from the 2 points of each shear to the column distributes the loads which can be encountered not only in the press but also in the draft evenly.

Our shear profiles are specially designed in D form, thus increasing the resistance against vertical loads and providing minimum contact with the plastic cover. In this way, while the plastic cover is not damaged, a higher carrier and strength value is provided compared to similar profiles. Belt beam profiles are selected in D form with dimensions of 50 × 60 mm by means of compression and draw loads calculations and shading surface calculations.

When designing the shears, plant, fruit and vegetable loads are divided into 5 equal sections and all connections are locked to the load balance points for a balanced distribution of the loads. In this way, the entire greenhouse is in static communication with each other and the greenhouse is able to resist loads as a whole. Shear profiles were chosen as Ø32 mm according to load balance calculations and shading surface calculations.

The profile passing under the shears is made of round pipe profiles in other structures. This element creates difficulties in the installation and isolation of the curtain system. Our profile system under the shears is shaped in oval form; oval profiles in the horizontal plane are more static than round sections; have strength and deflection values. Oval section profile we use is 40×25 in size.

With its innovative engineering design, carrier side and purlin profiles are important carrier profiles that are directly exposed to loads and transfer these loads to the columns. In general, applications, the clip profiles are screwed or welded so that the plastic cover can be mounted on these profiles. In our system, the clips and bearings that can be mounted by attaching the carrier and plastic cover are shaped on the same profile and thus an important innovation and practicality has been achieved.

The lock bearing form has provided a significant installation speed and ease with a considerable economy of manufacturing and assembly labour. Clip bed infrastructure is prepared for fly tulle applications. This method combines all functions with a single profile. The sizes of Purlin profiles are 40 × 50, they are ribbed and pass around the greenhouse in 3 rows and are 2 times more resistant to distortion and buckling than their equivalents.

One of the most important issues in greenhouse is ventilation and proportional humidity. Relative humidity in greenhouses should be 60-70%. Higher relative humidity increases growth and stops root growth. Lower relative humidity is undesirable as it increases evaporation in the greenhouse. Greenhouse windows should have a 40% ventilation opening relative to the floor area for good temperature and humidity control. Therefore, large window sizes are needed. Window profiles must be resistant to wind loads and vibrations as carriers. As in the beam profile, the clamped profile, which is designed as half oval, provides minimum contact from the tangential point to the plastic cover, it is an ideal form with high moment of inertia values and high strength and carrying property. The opening and closing system is made automatically by the motors with reducer suitable for automation.

We have observed that the most important problem with greenhouse windows is distortions and axial shifts of the window handles. As a solution, the window handles were placed every 1.5 meters instead of being placed at 3 meters. The skewing, sliding and bending problems in the windows were solved by placing diagonals from the moment reset points. Half oval window profile is 30×40 in size and 2 m in length.

Wind tensioners are generally made of pipe profiles in conventional greenhouses. At horizontal and non-axial angles, oval profiles have higher tensile and compression values than round profiles. This ideal form allows us to achieve higher strength values. Columns and roof show different resistance to wind loads. In addition to our system, roof trusses are reinforced with roof tensioners against wind loads. Against different wind directions, static rigidity is ensured by strengthening the system with forehead corners, side and inner column tensioners and roof wind tensioners.

Our rain gutters are produced in multi-station roll-form machines to meet the gothic structure loads and make the rainwater discharge smoothly for many years. It is in a unique form that transmits the perspiration water in the greenhouse to the outside of the greenhouse and provides a disease-protected environment for controlled plant production with good humidity control. The opening of our gutters is 50 cm and its deep structure provides high water carrying capacity, its ribbed structure provides high static strength and minimum shade rate.

Polyethylene cover is fastened with special PVC continuous clips that are made of two parts with interlocking after the assembly of construction, special section galvanized clip profiles, self-clip groove, purlin ridge and window profiles manufactured by our company. In addition to ease of installation, these clips provide long cover life and ensure resistance against double wind effects as well as sealing.  Thanks to our clip system, it is possible to inflate the entire surface of the greenhouse with air and provide heat insulation. Our locked clip system provides high protection against wind. Our clip system is widely and safely used by sera manufacturer companies throughout the country.

As the surface area affected by the wind increases in long greenhouses, the polyethylene cover is subjected to very strong pressure and loads in strong winds and this situation causes tearing. The roof and window plastic covers are divided in two with double clips to reduce the pressure surface and protect against tearing. This application facilitates the installation, replacement and repair of plastic covers and minimizes damage.

For proper ventilation, a top ventilation opening is required to ensure that the indoor airflow rate of the greenhouse is emptied and replaced with fresh air within 1 minute. 2.00 m on the top and 2 pieces in width, 4 meters in total. There is a butterfly model ventilation system that provides 40% high ventilation rate. This model enables efficient ventilation and climate control. The friction and power losses are minimized thanks to the specially manufactured hinge system and the shaft bearings.

By means of computer-controlled bi-directional gearmotors with safety limit switches and motion-guided gear gears, the ventilation system is switched on and off by computer automation according to the measurements taken from humidity, heat, wind speed, wind direction and rain sensors.

Clamps connecting the elements in the greenhouse; are moulded in special form and design and this provides modular installation without welding. The connectors are multifunctional, providing several practical functions and speed of installation. The bolts and nuts used are galvanized and all nuts are used with fiber against loosening in vibrations. The bolt group used for connections is made of steel and complies with such bolt norms as DIN-931, DIN-933, DIN-985, DIN-125, DIN7504N and DIN-934. All of our clamps are made of 2 mm galvanized material and radius points have an engineering design that distribute the loads evenly over the connection area and has successfully passed static tests.

Doors we manufacture are Polycarbonate coated, have mortise lock, sealed with EPDM rubber cord, made of galvanized steel body, have stylish and elegant base; double rail slide system at the top and bottom, size: 3 m in width and 3 m in height.