Production of stairways and platforms - exchange rate

Contents

Entry

1.Technical Requirements

2. Calculation of requirements for valves according to production system

3. Selection of main process equipment

4. Description of the production technology of rebar products

5.Control and quality assessment of reinforcement products

6. Conclusion

List of sources used

Introduction

Reinforced concrete structures consist of two equal materials - concrete and reinforcement. Concrete, as a rule, perceives compressive forces, and reinforcement, depending on the nature of power influences (price-tral compression, off-center compression and tension bending, etc.), perceives compressive or tensile forces. The joint work of reinforcement and concrete in a reinforced concrete element is made possible due to the adhesion of concrete with reinforcement and close values ​ ​ of the coefficient of linear thermal expansion of concrete and steel.

It is known that a concrete beam that does not have reinforcement in the stretched zone is torn at a load 10 times smaller than reinforced concrete of the same size, with the same grade of concrete, but reinforced in the stretched zone with steel reinforcement. The above example shows that the purpose of reinforcement in reinforced concrete structures is large. If the reinforcement is not laid correctly or is manufactured with a deviation from the working drawings during the manufacture of reinforcement elements, or technological errors are made: soaking or non-penetration of welded joints, use of low-quality electrodes for welding, tempering of reinforced steel, etc., then the manufactured reinforced concrete structures will not have the required load-bearing capacity, rigidity and crack resistance. Types of reinforcement steels:

All reinforcement steels used for reinforcement of reinforced concrete structures are classified according to the following features: according to the conditions of its use in structures, according to production conditions and mechanical properties.

According to the purpose, the valves are divided into working, distributing, mounting and clamps.

Selection of main process equipment

Reinforcement products should be manufactured with maximum factory readiness in specialized reinforcement workshops. At the plants of reinforced concrete products with centralized supply of mass products (grids, frames, embedded products, etc.), sections should be organized for the manufacture of small-scale reinforcement products and their pre-assembly.

Reinforcement works shall be carried out using complex-mechanized and automated lines and equipment for billet, welding, assembly and corrosion protection of elements of reinforcement products, as well as for their transportation and packaging with maximum reduction of manual labor, metal saving and power consumption.

Placement of equipment and in-line mechanized lines for rebar works shall be performed according to the types of works, maintaining the sequence of rebar products manufacturing according to groups of one purpose with the necessary in-house and lifting and transportation equipment.

Transportation of reinforcement steel and semi-finished products inside the reinforcement shop, as well as supply of finished reinforcement products to molding shops should be carried out in special containers, on self-propelled transfer trolleys, on suspended conveyors, etc.

Reinforcement workshops and sections, primarily at newly built and reconstructed enterprises, should be as close as possible to molding workshops. The warehouse of finished reinforcement products should be considered near the molding line mold preparation posts. When organizing work in rebar shops and areas, as a rule, oncoming and crossing process flows should be excluded. By-pass of finished reinforcement products in reinforcement and molding plants shall comply with ONTP 780. Reinforcement elements for various products should be manufactured in compliance with established technological rules and standards with accuracy corresponding to the requirements of GOST 1092275.

Billet of rods from reinforcement wire supplied in windings must be made on correct-cut machine tools SMZH357, GD 16201.

Rod and wire reinforcement should be cut on machines SMZH322A, SMZh-172A, and rolled stock should be cut on NB633. The SMZH322 machine is most efficient in operating conditions, it is equipped with a back pressure cutting mechanism, providing an even cut of the rod, perpendicular to its axis, without burrs and folding of the end.

Bending of mounting loops is carried out on bending machines SMZH146, and bending of grids on SMZH353, the peculiarity of which is that it is possible to bend grids of different lengths within the minimum and maximum size.

Types and structural elements of welded joints of reinforcement, as well as process modes of welding must be performed in accordance with GOST 1409868, RTM 39394 and design documentation for specific types of products.

Rebar meshes shall be fabricated on specialized installations by means of contact welding. For welding of upper mesh, KTS06 machine is used, for welding of reinforcement frames MT1928, for welding of embedded parts ADF2002. TEP2 ticks are used to assemble rebar frames.

The movement of reinforcement steel from the warehouse to the workshop is carried out on a rail trolley.

Transportation of reinforcement steel, reinforcement grids in the workshop is carried out by a bridge crane - KM - 10.

4. Description of technological production

Reinforcement steel is supplied to the warehouse. Reinforcement steel is placed in the warehouse and stored according to grades, profiles, diameters and batches. Transportation of reinforcement steel from the warehouse to the reinforcement workshop is carried out using a rail trolley, and transportation of reinforcement steel through the workshop is carried out using a bridge crane. A pro-wolf in the bays is stored at the beginning of the workshop on a specially prepared site. Unwinders - coils holders are installed at a distance of 11.5 m and SMZH357 correctly-cut machines are installed from them after 22.5 m. Receiving racks of reinforcement blanks along the line flow. Then there are installed machines for bending mounting loops SMZH146 and machines for bending grids SMZH353.

At the beginning of the workshop there are also machines for cutting SMZH322A reinforcement, NB633 presses are used for cutting rolled stock. Reinforcement steel is supplied to these machines through roller tables. And cut rods are folded on special platforms.

After cutting machine NB663, contact welding machine KTS06 and MT1928 is located. Near this machine there is a machine for welding under the flux ADF2002.

The movement of welded rods and grids is automated. Reinforcement steel is supplied to the machine by means of special feeding steel. Finished grids are stored on special sites.

At the very end of the workshop there are ticks for assembling rebar frames.

After all reinforcement parts have been made, they are moved by means of a bridge crane to the molding shop.

Quality control and evaluation of reinforcement products

Control of technological progress of manufacturing, reinforcement products includes: quality check of preparation of reinforcement, components of embedded parts for welding; verifying that the selected welding mode is correct quality control of welded joints of reinforcement and embedded parts during their manufacture and quality control of finished reinforcement products. The quality of welded metals (reinforcement, sheet and profile steel) should be considered satisfactory and they can be welded if the reinforcement class and steel grade correspond to those specified in the design; reinforcement diameters, thickness of sheets, strips, dimensions of profile rolled stock, established during measurements, do not differ from those specified in the design and do not exceed the limits of tolerances regulated by state standards or technical instructions: there are no permissible defects of reinforcement. Electrodes used for manual arc welding of embedded parts elements are accepted after checking compliance with the type, grade and diameter indicated in the accompanying certificate specified in the design and requirements of SNiP 3.03.0187. External inspection, technical characteristics and dimensions of electrodes shall comply with the requirements of GOST 946675 and GOST 946775. The certificate (certificate) accompanying each batch of electrodes indicates the name or trademark of the manufacturer, the symbol of the electrodes, the batch number and the date of manufacture, the mass (net) of the batch, kg; Electrode Rod Wire Tag: Standard or Specification Designation warranty shelf life. In the absence of data on the characteristics in the accompanying documents or in the presence of doubts about their correctness, tests are carried out in specialized laboratories in order to establish the welding, technological and mechanical properties of the electrodes. This rule applies to fluxes and welding wire.

Welded reinforcement products shall comply with the technical requirements of GOST 1092290. The quality of the products is established by selective inspection of a batch made by one welder.

The controlled batch shall consist of reinforcement articles of the same type-size (grade). If reinforcement products are used inside the manufacturer (moulding areas making prefabricated reinforced concrete), then one controlled batch can also include: windings in which the smaller of the two intersecting rods have the same cross-sectional area; frames, different, with transverse rods of reinforcement of the same class and diameters differing not more than:

more than two adjacent profile numbers;

rods connected by contact butt welding, with constant cross section along the length and diameters differing by at least two adjacent profile numbers.

The total volume of the controlled lot shall not exceed the number of items manufactured by one welder during one shift.

Compliance of reinforcement products with technical requirements of GOST 1092290 shall be checked by OTC during inspection and measurement of at least three products selected by uncontrolled batch at least twice per shift. In each rebar articles the following shall be checked:

- reinforcement classes and diameters according to these passports, and in their absence - according to the results of laboratory tests of steel;

- dimensions, distances between five pairs of rods, including extreme ones, at two points along the length of the rod;

- presence of reconciliation in the units;

- all welded joints made by arc welding with extended seams of at least five welded joints made by other welding methods.

Displacement of rod axes at their butt welding is measured with a rack and a ruler. In cross-shaped joints made by contact spot welding, the settlement of rods should be measured according to the procedure given in GOST 1409885 with an accuracy of 0.1 mm.

If during external inspection and measurement at least one of the three selected reinforcement articles of the batch does not meet the requirements of GOST 1092290, then double the number of articles should be re-checked. If the requirements of the standard do not meet at least one of the six selected products for re-inspection, all products of this batch are subject to individual acceptance and correction.

During the manufacture of temporary end anchors, it is necessary to ensure that the clips for pressure testing are made of steel of the St1 grade... STS, and their dimensions corresponded to the values ​ ​ specified in GOST 1092290.

When landing the heads in the hot state, it is necessary to check the distance between the outer faces of the fixed contact clamps with a template. Before placing the rods in the unit, check whether there are pre-prepared support washers at their ends. The diameter of the orifice of the washers shall not exceed the outer diameter of the rods by more than 2 mm.

Quality control of temporary end anchors and reinforcement elements billet with them consists in check of distance between support planes of end anchors and their strength. Control of standing is carried out selectively with a control template at least twice a shift.

The strength of temporary end anchors in the form of landed heads is controlled by testing them for breaking at least twice a shift, and in the case of the use of pressed washers, tests are carried out on

pulling rods out of anchors.

The tensile or pulling strength of the temporary end anchor shall be at least 90% of the standard resistance to the break of the original steel. All tests must be carried out in accordance with the requirements of GOST 1092290, and their results must be entered in the test log.

6. Conclusion

A rebar workshop was designed for the production of staircases. The production capacity is 50,000 m3/year. All necessary equipment is selected for straightening, cutting, bending, welding of reinforcement, depending on the type, shape, diameter of reinforcement. The storage area for reinforcement steel storage is also calculated, taking into account all the necessary requirements.

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