HarbinSingle story warehouse with closed windows

Tall bungalow warehouses have the characteristics of being sealed, moisture-proof, insulated, heat-insulating, and airtight. They are the most commonly built and used type of warehouse in grain storage enterprises. Due to factors such as large warehouse capacity, high grain storage capacity, long storage time, and different regional environments, the performance of the warehouse will continuously decrease with the extension of its service life. Harbin Grain Reserve Warehouse, based on the performance requirements of warehouse use and local environmental conditions, has conducted advanced analysis and planning from the aspects of warehouse design and construction, warehouse use and maintenance, strictly grasped engineering quality and daily management of warehouses, and explored ways to extend the service life of warehouses and improve their efficiency.

1、 The main factors affecting the performance of warehouse use

All warehouses are designed according to grain storage technology and can meet various operational requirements for grain. The factors affecting the performance of warehouse use are analyzed as follows:

（1） The impact of climate and environment. The city has a northern temperate monsoon continental climate with distinct four seasons. In summer, the temperature is high, humidity is high, precipitation is concentrated, and sometimes it is affected by combined winds; The temperature drops sharply in autumn, the rainfall decreases sharply, and the autumn is cool and crisp; In winter, rain and snow are rare, and it is cold and dry. The annual average temperature is 12.5 ℃, the annual average air pressure is 1015.9 hectopascals, the annual average precipitation is 613.6 millimeters (mostly concentrated in summer, accounting for 65% of the annual precipitation, with large interannual variations and prone to drought and flood disasters), the annual average evaporation is 1926.0 millimeters, the annual average wind speed is 3.3 meters per second, the annual average ground temperature is 14.6 ℃, and the annual maximum frozen soil depth is 600 millimeters. Due to the humid climate, rainy summers, and large temperature differences, it is necessary to ensure moisture and leak prevention, as well as sealed insulation during warehouse construction.

（2） The impact of geological environment.

（3） The impact of the surrounding environment.

（4） The connection between warehouse supporting facilities and modern grain storage technology. The storage period of reserve grain in tall bungalow warehouses is long, and the volume of grain piles is large. Sufficient modern grain storage facilities such as grain condition detection, mechanical ventilation, circulation fumigation system, etc. must be equipped to serve the monitoring, control, and processing of grain conditions in the safe grain storage process. While extending the service life of the warehouse main body, attention should also be paid to the use and maintenance of supporting facilities.

2、 Strictly carry out warehouse design and construction to ensure project quality

Starting from the performance that a grain warehouse should possess and taking into account local environmental conditions, the following measures have been taken in the design and construction process to improve the usability of the warehouse.

（1） Main structure. The wall structure, roof truss beams, etc. comply with seismic requirements and meet the lateral pressure requirements of grain piles.

（2） Warehouse foundation and walls. Based on the impact of saline alkali environment, technical operations such as trenching and excavation were carried out. During the construction of the warehouse, all exterior wall base layers were treated with oxalic acid and then coated with two coats of putty and two coats of oil-based exterior wall latex paint to prevent corrosion and penetration of the walls caused by rainwater and other factors.

（3） Moisture proof and leak proof. One is the roof structure, with roof panels, perlite, and warehouse roof waterproofing all using high polymer modified asphalt SBS waterproofing rolls. High polymer modified asphalt additional layers are added at the roof partition joints, internal gutters, parapets, and wall corners. Secondly, the inner wall is equipped with a 300 gram/square meter thick polyethylene polypropylene moisture-proof layer below the grain storage line. Thirdly, the floor inside the warehouse should ensure thickness, compression resistance, and not damage the moisture-proof layer. The floor is equipped with a 500 gram/square meter thick polyethylene polypropylene moisture-proof layer.

（4） Thermal insulation. Ensure proper installation of doors and windows, relevant insulation measures, and airtightness testing of the warehouse.

（5） Process improvement. In the engineering construction, the stainless steel circulation fumigation pipeline in the original design scheme was changed to a PVC pipeline of the same diameter and installed inside the warehouse, which solved the disadvantages of stainless steel pipelines being easily corroded by the environment outside the warehouse, prone to condensation inside, and dew flowing back into the ventilation opening. In the second, third, fifth, and sixth phases of construction, combined with grain storage practice, the shortcomings of the first phase of the project were continuously improved and perfected, such as changing the mechanical ventilation openings and ladders to the north side of the warehouse, which solved the disadvantages of unfavorable temperature insulation at the ventilation openings in summer and easy condensation during winter ventilation.

3、 Seriously carry out warehouse use work and build a solid management foundation

（1） Newly built warehouse for the first time. One is to do a good job of drying inspection for the newly built warehouse. After the new warehouse is built, the walls and floors are very damp, requiring a drying process that takes about six months. Only when the warehouse is completely dry can it be stored. If the construction process of "inside first, then outside" plastering is adopted during construction, the drying period of the warehouse can be shortened to three months. Before entering the warehouse, it is necessary to conduct a drying inspection. The method is to stick a new plastic cloth on the wall and floor in a dead angle of ventilation. The plastic cloth should be firmly adhered with wide transparent tape around it. After 24 hours, check whether there are water droplets or moisture inside the plastic cloth. When there are no water droplets or moisture present, it indicates that the walls and floors have dried and reached the conditions for storage and grain loading. The second is to reasonably compress the warehouse. After the construction of the new warehouse, there is a natural settlement process. By preloading the newly built warehouse, the foundation of the new warehouse is uniformly settled and gradually compacted to prevent the warehouse from being subjected to large loads before settlement, resulting in uneven settlement of the foundation and damage to the warehouse structure. The initial warehousing should be carried out in two stages, with each stage containing 60% and 40% of the warehouse capacity, respectively. Before the initial storage, during the storage process, and during the compression period, the displacement of the scaffolding columns and walls should be observed; Careful observation should be made on all parts of the bungalow warehouse for any abnormal conditions, especially on the edges of the door and window openings, the corners of the warehouse, the middle of the partition wall, and the connection with the eaves wall for any cracks or deformations. When abnormal phenomena are discovered, drawings and written records should be made, and relevant design units should be contacted in a timely manner to jointly study and handle them. The third is to do a good job in observing the settlement of the warehouse, setting up benchmarks and observation points at designated locations. The warehouse is equipped with permanent leveling points, and the settlement observation points on the warehouse wall are fixed on the outside of the warehouse wall with expansion bolts. The settlement observation system on the mainland is set up by vertically fixing expansion bolts within the floor surface layer, with the top of the steel bar head parallel to the ground surface. Fourthly, during the initial storage, attention should be paid to balancing and slowing down the loading, avoiding prolonged overloading, measuring settlement on time, and keeping records. When a warehouse has several compartments, each compartment should be stored in equal quantities at the same time to ensure even settlement of the floor and safety of the partition walls.

（2） Rotating warehouse inbound and outbound. One is to conduct settlement observation in a timely manner after rotating the warehouse out of the warehouse, record various data in detail and compare them with the previous observation data, conduct detailed inspections of the walls, floors, and other parts of the warehouse, and promptly deal with any problems found. After the completion of storage, timely inspection, observation, and comparison should also be carried out. The second is to arrange the entry and exit time and sequence of each warehouse reasonably. For a single story warehouse consisting of two or more compartments, adjacent compartments should be arranged for simultaneous entry and exit or the loading time of one compartment should be shortened as much as possible. It is also not allowed to only install one compartment and leave the other compartments vacant. The third is to maintain a balanced inventory of the entire warehouse building, avoid uneven settlement, and strictly prohibit excessive storage.

4、 Solidly maintain the warehouse and optimize its performance

Proper daily inspection and maintenance of the warehouse is an important way to maintain and restore its original quality and function, ensure safe and normal use, and extend its service life.

（1） The main direction of warehouse maintenance. Taking maintenance and minor repairs as the main method, implementing a combination of repair and prevention, division of labor and responsibility, striving to maintain the warehouse well, delaying the aging speed of various parts and components of the warehouse, taking turns to carry out comprehensive maintenance in a step-by-step manner, in order to improve the quality and integrity of the warehouse, reduce investment in warehouse construction, and maximize the service life and function of the warehouse.

（2） The method of warehouse maintenance. One is to establish a comprehensive system for the daily maintenance of the warehouse, including detailed workflow from use, cleaning, inspection, maintenance to repair, clarifying responsibilities, and implementing seamless management. The second is to conduct a detailed inspection of all warehouse exterior walls before the rainy season each year, and if cracks or ruptures are found in the latex paint on the exterior walls due to aging. Clean the cracks in a timely manner and apply putty and oil-based exterior wall latex paint according to the construction requirements. The third is to conduct frequent inspections of the warehouse roof, keep detailed records, and promptly address any issues found. When the SBS waterproofing membrane cracks due to aging, the surface protection should be scraped off clean, and then sealed with sealant. Two coats of base treatment agent compatible with the membrane material should be applied, and a SBS modified asphalt waterproofing membrane larger than the crack (with a 200mm overlap around the perimeter) should be cut and laid on the crack. The fourth is the inspection and maintenance of warehouse walls. The wall is another important component of the warehouse, which is prone to cracks or damage caused by collisions with mechanical equipment. When cracks are discovered, the old mortar at the crack should be removed and moistened with an appropriate amount of water after the crack has stopped developing and is in a stable state. Then, high-grade mortar should be used to fill the gap and restore the bonding strength at the crack. If there are fine cracks, apply three coats of "acrylic" waterproof coating directly at the crack according to the construction requirements. Damage caused by collisions with mechanical equipment should be promptly addressed by dismantling, repairing, or reinforcing according to the degree of damage. When the moisture-proof layer on the wall breaks, it needs to be repaired first before repairing the wall. The fifth is the inspection and maintenance of the floor. With long-term use of the warehouse or poor treatment of the original site, cracks, pits, and defects in the floor may occur, causing partial or complete loss of moisture resistance. When the moisture-proof layer is damaged, it is necessary to repair the moisture-proof layer first and then repair the ground. When repairing cracks in the cement floor, the cracks should be appropriately chiseled wide, and the newly chiseled joints should be cleaned with clean water, brushed with interface agent or cement slurry, and then repaired with high-grade cement concrete. During the repair, care should be taken not to damage the moisture-proof layer. The sixth is the inspection and maintenance of warehouse iron parts. Iron components such as doors, windows, ventilation openings, steel supports, and distribution boxes that are used for a long time and exposed to wind and rain, as well as the influence of saline alkali climate, can cause paint peeling, rusting, and other phenomena. If not treated in a timely manner, they can cause corrosion and damage. Therefore, for peeled paint surfaces, repaint them, thoroughly remove rust, and then apply anti rust paint and topcoat. Regularly lubricate the shafts and lock blocks of doors and windows to ensure that all iron parts are rust free and extend their service life. Seventh, establish and improve maintenance records. Before each maintenance and construction, it is necessary to carefully review the archives and materials of previous inspections and repairs, conduct scientific analysis, and make maintenance plans based on this, in order to achieve correct material selection and meticulous construction. Through the records of each inspection, maintenance, and repair, the true quality information and improvement suggestions of each warehouse can be reflected.