Organization of warehousing

Warehousing is organized in order to create the conditions for the timely maintenance of construction projects with building materials in the required quantity and in full nomenclature.

Warehousing should provide acceptance of materials with the definition of their quality and quantity; rational placement and laying of materials, mechanization of loading and unloading operations; improvement of storage techniques for materials, structures and products; the smallest loss of materials during storage; the organization of the issue of materials; accounting of material values.

The cost of building materials is 55-60% of the total cost of construction, so the proper organization of warehousing is of great importance in reducing the cost of construction.

According to its operational purpose, warehouses are divided into the following types:

- Reloading warehouses for temporary storage of materials and products when reloading them from one mode of transport to another. Such warehouses are created in the conditions of a large dispersal of construction and considerable transportation distances. Cargoes are delivered by rail or by water in relatively large batches after a certain period of time; these materials and parts are delivered to the construction site more evenly and in small batches.

- Basic (central) warehouses are designed to service a number of facilities built by a single construction organization. Such a warehouse, mainly closed storage (nails, hardware, hardware, glass, paint, clothing, etc.) is located on the territory of the largest construction site or outside it, but at the access roads. Materials, products and equipment that require sorting and picking are also delivered to the base warehouse. Transshipment and basic warehouses cause an increase in the cost of construction, therefore it is necessary to strive to ensure that materials, parts and structures are supplied to the object under construction, bypassing these intermediate warehouses.

- Precinct warehouses are used to store materials, products and equipment coming from suppliers or from basic and transshipment warehouses, they are intended for objects of a separate section.

- On-site warehouses - are arranged in close proximity to objects under construction (work areas). In most cases, these are open areas for the temporary layout of precast concrete products, wall materials, window and door blocks, brick containers, etc. For the storage of tools, clothing, finishing, electrical and other materials are arranged small mobile or collapsible storerooms.

- Warehouses of raw materials and finished products of subsidiary industrial enterprises and workshops for picking sites are located directly in the locations of enterprises, workshops and mobile units.

By design and storage method, warehouses are divided into the following types:

- Open - for storage of materials and products that are not exposed to damage from atmospheric and temperature effects (sand, gravel, slag, prefabricated railways, bricks, etc.).

- semi-closed (sheds) - for storage of materials exposed to damage from direct exposure to precipitation and sunlight, but not changing under the influence of temperature, humidity and wind (roll materials, carpentry, plaster products, etc.) :

- closed insulated and non-insulated - for the storage of valuable materials and materials that are subject to deterioration during open storage (cement, lime, dyes, hardware, glass, appliances, electrical equipment, tools, etc.)

- Special - for storage of fuel and LV. liquids, explosives, chemical materials, etc.

Methods and rules for storage of materials and parts in warehouses

In open warehouses, as well as over canopies and in enclosed spaces, a stack method for storing materials and parts is used. The bottom row of products in stacks is laid on wooden linings, and the subsequent rows are placed on gaskets from bars with a cross section of 6 * 6 and 8 * 8 cm (for concrete products) or from boards with a cross section of 4 * 12 and 5 * 12 (for concrete blocks)

Prefabricated structures and parts are stacked in piles separately by types and sizes of products. Stacks should be labeled or tagged with the number and type of parts laid. The layout of prefabricated structures should comply with the accepted scheme of assembly works and provide the best working conditions for installation cranes and scaffold gear.

Blocks of basement walls, as well as columns, are stacked in piles in several rows (up to four) with a total height of not more than 2.25 m. Piles are placed in one or two rows. Crossbars are stacked in stacks in rows (two or three) on the edge with linings and gaskets at a distance of 1.2 m from the ends of the product.

Floor slabs (hollow cores) are stacked in piles in rows (up to 10-12), but not more than 2.5 m in height. Lining and gaskets are located at a distance of 0.6 m from the edges of the plate. Wall panels are stored in a vertical or inclined position (within 10-12 degrees) in special metal cassette devices. Concrete wall blocks with a height of 1.25 m and more are installed in a warehouse in one row, and the rest are in 2-3 rows, but the total height of the stack should not exceed 2.5 m. The linings and gaskets from the bars should be indented from the block faces not less than 5 cm and no more than ¼ of the length of the elements.

For storage, storage, transportation of T-section beams, special cassettes are used to hold the products in the “edge” position.

Reinforced concrete trusses are stored in the working position with a slight slope so that the outermost truss is located on support posts that are installed against the upper nodes. Lining should be laid under trusses in supporting parts.

The brick is stored in grades and brands, and the front brick - the color of the front surface. The brick is delivered to the construction site, usually laid on pallets "in the Christmas tree" in 10 rows with a brick tilted at an angle of 45 degrees to the middle of the pallet. Such a package when loading and lifting (with the help of grabs) is not destroyed.

Bags from cars are removed with cranes and fall directly on the workplace of bricklayers, or on an on-site warehouse with stacking in continuous tape piles in 1 or 2 rows.

Rubble stone is stored in an open area in rectangular piles with a volume of up to 200 m3 and a height of up to 1 m with manual and up to 3 m with mechanical loading.

Non-ore materials (sand, crushed stone, gravel) are placed in fractions, in open areas, as well as in mechanized bunker-type warehouses.

Steel, steel structures and pipes are piled up in open areas or on racks under sheds. Materials should be divided by type, grade, brand, profile and size.

Round and sawn wood is stored on construction sites only in special cases. Round wood and lengthy sawn materials are stacked in piles, located on open dry areas with a small slope for water flow. The height of the stack is determined by the type of material being stored and the method of laying. Under construction conditions, it usually does not exceed 1.5–2.5 m. In large timber warehouses, if there are special loading mechanisms (auto-loading forks, stackers, etc.), the stack height can reach 10–12 m.

Depending on the type of materials stored and climatic conditions, semi-closed warehouses (sheds) can be open on three sides or upholstered boards or other materials on two or three sides. Sheds should be collapsible from the universal type sections. Roofing roll materials, sorted by brand under canopies in a vertical position, laid on the “butt”, no more than two rows in height.

Joinery is stored in piles by type, size and class, stacked on pads, protected from contamination, moisture and icing, as well as in special containers for storage, transportation and supply to the workplace.

Closed warehouses should:

1. Have the necessary fire-fighting devices, heating and ventilation (in the required cases);
2. Be quite capacious. Internal layout and equipment to meet the nature of the operations for the receipt and release of materials;
3. Have reliable protection against penetration of precipitation, groundwater and surface water.

There are standard designs of heated and unheated closed warehouses of wagon, collapsible and stationary types.

Cement, lime, gypsum and other materials exposed to moisture are stored in closed warehouses of a concealed, bunker or silo type, by make and “age”.

Determining the stock of materials, storage areas and loading fronts.

The total area of ​​the warehouse consists of useful, directly occupied by materials, parts, structures and auxiliary, occupied by aisles, driveways, service premises. To calculate the size of the warehouse is pre-set the number of materials, parts and structures to be stored.

- the amount of material, parts, structures required to perform a given amount of construction and installation work for the planned period,

n - the rate of inventory of materials in stock (days);

–The coefficient of uneven receipt of materials to the warehouse, which is approximately 1.1 - 1.2 for railway and water transport, and 1.3 - 1.5 for automobile transport;

- the coefficient of uneven consumption of materials is 1.3 - 1.5;

T - the duration of the work on the schedule (days).

The estimated stock of materials, depending on the local conditions of supply, the type of transport that delivers the materials and the organization of its work, as well as the distance of transportation and the time of year, should be minimal on the construction site, but at the same time guaranteeing uninterrupted construction and installation work.
Approximate daily norms of the stock of materials and products.

When storing materials in bulk, in piles or bins, the warehouse area is determined by:

- the number of materials stored in the warehouse,

P is the storage rate on the useful area of ​​the warehouse.

The rules of styling P.

When storing materials on racks, the useful area of ​​the warehouse will be equal to:

, m2

- the required number of racks;

l is the length in meters;

b - rack width in meters.

- the amount of material stored in the warehouse;

- rack capacity in tons.

The capacity of the rack is determined by the formula:

l is the length of the rack in meters;

b - rack width in meters;

n is the height of the rack in meters;

- bulk weight of the material;

- the filling ratio of the rack for the directory 0,6 - 0,8.

The total area of ​​the warehouse (i.e., the area including passages, passages, etc.) in all considered cases will be equal to:

, m2

k is a coefficient taking into account the dimensions of passages, aisles, office space, etc., taken to be:

• for open warehouses for bulk storage - 1.15 - 1, 25;
• for closed and bunker storage - 1.3-1.4;
• universal - 1.5 - 1.7 ;
• when stored in stacks - 1.2 - 1.3.

After determining the area of ​​the warehouse set its dimensions in terms of - length and width. The smallest size of the unloading front is determined taking into account the provision of the necessary front loading and unloading operations, the technical capabilities of the machines and mechanisms used and the characteristics of the materials in form.

m is the number of simultaneously unloaded vehicles;

l is the length of the transport unit, m;

- the interval between transport units when installing them for unloading, m

Upon delivery of materials to the warehouse by truck, the number of units of simultaneously unloaded vehicles m can be calculated by the formula:

;

- the amount of cargo arrived at the warehouse in the shift ( T );

- car load capacity, (t);

- the duration of unloading one car (min.);

t - the duration of the shift (min.);

k - the coefficient of non-uniformity of the arrival of cars is 1.5 - 1.2.

When transporting materials to the warehouse by railway transport, the largest number of cars that will be under unloading is determined by:

- number of materials arrived by rail per day, tons;

- the duration of unloading of cars and platforms, served for one supply to the warehouse, hours .;

k - coefficient of uneven receipt of materials, equal to 1.5 - 2;

- carrying capacity of cars, tons;

n is the number of innings per day;

- the duration of the unloading of cars according to the norms established by the Ministry of Railways (h).

The width of open warehouses depends on the range of cranes and machines used for unloading and loading. It should be borne in mind that increasing the width of the open warehouse complicates the internal warehouse transport.