BASIC PRINCIPLES OF BUILDING STRUCTURE INSTALLATION TECHNOLOGY 4. Ways and means of transporting structures

Delivery of structures to the construction site can be carried out by all modes of transport, namely, land - by road, rail, tractor; water and air.

The main factors influencing the choice of construction transport:

■ location of construction;

■ existing near transport communications;

■ location of factories completing the construction of prefabricated structures;

■ time and weather conditions;

■ weight, dimensions of structures, distance of their transportation.
The main type of transport for the transportation of precast concrete is automotive with a transportation distance of up to 200 km.

The release of prefabricated structures is made when the concrete reaches 100% strength in winter and 70% strength in summer, provided that the manufacturer guarantees that the concrete will gain brand strength by 28 days old.

Elements with a length of up to 6 m are transported by on-board cars. Longer elements - on road trains with trailers and on flatbed semitrailers with a mass of elements more than 14 tons; on trailer trailers - up to 40 tons; on the panel-, farm-, blokovoz - up to 35 tons.

When transporting lengthy structures on farm trucks and similar vehicles, lateral forces from passing waiting curve road sections are perceived frame cars. The speed of movement of transport is prescribed for reasons of safety of delivered structures.

Laying of precast elements on vehicles produced with the following requirements:

■ items must be in a position close to the design, with the exception of columns that are transported in a horizontal position;

■ it is necessary that the elements rest on wooden inventory pads and linings located in the places indicated in the working drawings for the manufacture of these elements. The thickness of the gaskets and linings must be at least 25 mm and not less than the height of the loops and other protruding parts of the elements. The use of intermediate gaskets is not allowed;

■ in case of multi-tiered loading, the lining and gasket should be placed exactly one vertical;

■ elements must be carefully strengthened in order to prevent tipping, longitudinal and lateral displacement, as well as impacts against each other;

■ The textured surfaces of the elements must be protected from damage.

Horizontally transport elements laid in a structure and working in a horizontal position: beams, bolts, girders, slabs and floor panels, balcony and roofing slabs, high (more than 1.5 m) wall blocks; and also length prefabricated structures - columns and piles.

Vertically and obliquely transport trusses and trusses, wall panels, partition panels.

Volumetric elements - block rooms, block apartments, sanitary cabins transported in the design position.

Transportation by rail is allowed only over particularly long distances. Long products are transported on two platforms with articulated support, excluding the occurrence of bending forces in the transported structures on curved sections of the railway track.

Metal structures are often delivered by rail over long distances in the form of separate composite nodes, while small metal elements are transported in packages.

Wooden structures, because of their low rigidity, are rarely transported in finished form, mainly in packaged form, disassembled.

When transporting by road and rail, the size of the goods must fit into the dimensions of the rolling stock. Any deviations from these dimensions in height, width, length require special coordination and controlled transportation conditions.

The required stock of structures in the warehouse is established by the project of work, taking into account the calendar schedule of installation and the areas that can be set aside for the layout of structures in the crane area. The unloading of prefabricated structures delivered to the construction site is usually carried out by a special unloading self-propelled crane and, less commonly, by the main assembly mechanism. More economical and less time consuming is “mounting from the wheels”.