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Minimum formwork turnover in cycles. Plywood formwork: types, manufacturing methods and advantages Temporary or partial non-use

FORMWORK REVERSIBILITY number of cycles of repeated use of formwork without losing it performance qualities

(Bulgarian language; Български) - appealability for cofrage

(Czech language; Čeština) - opakované použití bednění

(German; Deutsch) - Wiederverwendbarkeit der Schalung

(Hungarian; Magyar) - zsalufordulo

(Mongolian) - hashmalyn ergelt

(Polish language; Polska) - rotacja deskowania

(Romanian language; Român) - reutilizare a cofrajelor

(Serbo-Croatian language; Srpski jezik; Hrvatski jezik) -obrt opiate

(Spanish; Español) - Indice de reutilización del encofrado

(English language; English) - formwork reusing

(French; Français) - réutilisation du coffrage

Construction dictionary.

See what "FORMWORK RURVERABILITY" is in other dictionaries:

formwork turnover- The number of cycles of repeated, repeated use of formwork without loss of its performance [Terminological dictionary of construction in 12 languages ​​(VNIIIS Gosstroy USSR)] Topics of construction. machines, equipment, other tools EN... ...

Formwork turnover- – the number of cycles of repeated, repeated use of formwork without loss of its performance qualities. [Terminological dictionary of construction in 12 languages ​​(VNIIIS Gosstroy USSR)] Term heading: Formwork Encyclopedia headings: ... ...

turnover- The amount of use of formwork (concreting cycle), determined based on experience using statistical data or a calculation method. Turnover before wear, before repair, turnover within a month, a year, etc. [GOST R 52086... ... Technical Translator's Guide

Turnover- – the amount of use of formwork (concreting cyclops), determined on the basis of experience using statistical data or a calculation method. Turnover before wear, before repair, turnover within a month, year, etc. [GOST... ... Encyclopedia of terms, definitions and explanations of building materials

turnover- 172 turnover The amount of formwork used (concreting cyclops), determined on the basis of experience using statistical data or a calculation method. Turnover before wear, before repair, turnover within a month, a year and... ...

Formwork- – design, which is a form for laying and curing concrete mixture. It consists of form-building, load-bearing, supporting, connecting, technological and other elements and provides the design characteristics of monolithic... ... Encyclopedia of terms, definitions and explanations of building materials

GOST R 52086-2003: Formwork. Terms and Definitions- Terminology GOST R 52086 2003: Formwork. Terms and definitions original document: 164 adhesion to concrete Adhesion, adhesion of the deck to concrete and concrete mixture Definitions of the term from various documents: adhesion to concrete 70 aluminum formwork... ... Dictionary-reference book of terms of normative and technical documentation

Components of formwork and formwork systems.

The basis of the effectiveness of any formwork system lies the possibility of its rapid modification in accordance with the requirements of the construction site. The lightness of the panels and the ease of assembly of the formwork make it possible to significantly increase the production rate of the entire complex concrete works, reduce the construction period. The manufactured formwork must guarantee optimal sizes panels, their high strength and rigidity, the quality of the concrete surface in contact with the formwork.

The individual elements of the formwork system are as follows: formwork - a form for the manufacture of monolithic concrete structure; shield – formative element

formwork, consisting of a frame and deck; shield frame (frame) – Basic structure formwork panel made of metal or wooden profile, manufactured in a jig that guarantees the accuracy of the external dimensions of the manufactured structure; shield deck - the surface in direct contact with concrete; formwork panel – large element formwork with a flat or curved surface, assembled from several panels connected to each other using special units and fasteners and designed to create required surface in specified sizes; formwork block - a spatial, closed or open formwork element consisting of several panels, intended for formwork of corner sections of a concrete structure, made entirely and consisting of flat and corner panels or shields; formwork system - a concept that includes formwork

and elements that ensure its rigidity and stability - fastening elements, scaffolding, supporting scaffolding; fastening elements - locks used to connect and securely fasten adjacent formwork panels to each other; ties that connect opposing panels in the formwork and other devices that combine the formwork elements into a single, unchangeable structure;

supporting elements - struts, racks, frames, struts, supports, scaffolding, floor beams and other supporting devices used when installing and securing the formwork of walls and ceilings, fixing the formwork in the design position and bearing loads during concreting.

Auxiliary elements formwork systems:

hanging scaffolds - special scaffolds hung on the walls from the facades using brackets fixed in the holes left when concreting the walls;

roll-out scaffolding – designed for rolling out tunnel formwork or floor formwork along it when dismantling it; opening formers - special formwork designed for forming in monolithic structures window, door and other openings;

Turnover is the repeated use of formwork, which is usually achieved by making it inventory, standardized and collapsible;

Main types of formwork

Formwork is classified according to its functional purpose depending on the type of structures being concreted and, in general view, subdivided:

For vertical surfaces, including walls;

For horizontal and inclined surfaces, including floors;

For simultaneous concreting of walls and ceilings;

For curved surfaces (mainly pneumatic formwork is used).

As a result practical use in domestic and foreign mass industrial and civil construction, they have been created and are successfully used depending on the characteristics of the structures being built, the formwork material, the conditions and methods of work whole line structurally different formworks, the most widespread of which are the following:

1. Collapsible small panel formwork from small panels with an area of ​​up to 2 m and a weight of up to 50 kg, from which it is possible to assemble formwork for concreting any structures, both horizontal and vertical, including massifs, foundations, walls, partitions, columns, beams, floor slabs and coverings.

2. Large panel formwork from large-sized panels with an area of ​​up to 20 m, equipped with load-bearing or supporting elements, struts, adjusting and installation jacks, scaffolding for concreting. It is designed for the construction of large-sized and massive structures, including extended or repeating walls, floors of buildings and structures for various purposes.

3. Block formwork, which can consist of individual formwork panels, combined into spatial structures using fasteners, or specially manufactured spatial formwork blocks for specific structures to be concreted. Formwork can be used for formwork internal surfaces stairwells, elevator shafts, closed cells of walls of residential buildings, as well as external surfaces columnar foundations, grillages, arrays, etc.

4. Climbing formwork, consisting of panels, supporting, load-bearing and fastening elements, working flooring and devices for lifting the formwork system. Constructive solution formwork allows you to separate the panels from the concrete structure before moving it to the next tier. Formwork is used for the construction of high-height structures of constant and changing geometry cross section- pipes, cooling towers, bridge supports, etc.

5. Volumetric adjustable formwork, used for the simultaneous construction of walls and ceilings of buildings. The formwork consists of L- and U-shaped block sections; the design allows the sections to move inward. Sections of formwork are connected to each other along their length, forming several parallel rows at once with distances between blocks equal to the thickness of the walls. This allows, after installing the formwork and laying the reinforcement cages, to simultaneously carry out concreting of the walls and adjacent sections of the floors.

6. Sliding formwork, used in the construction of vertical structures of buildings and structures of great height. The formwork is a system consisting of panels, a working floor, scaffolding, jacks, jacking rods fixed to jacking frames, and a control station for lifting the formwork system. Formwork is used for the construction of external and interior walls residential buildings, stiffening cores, as well as chimneys, silos, cooling towers and other structures with a height of more than 40 m and a wall thickness of at least 25 cm.

7. Horizontally movable formwork, the purpose of which is the construction of linearly extended structures with a length of 3 m, solved both in the form separate wall (retaining wall), two parallel walls (open collector), and a closed structure consisting of walls and a covering of the required specified length. The formwork is a rigid frame on trolleys with attached

to it with formwork panels, working flooring with fencing and mechanism

moving the formwork both vertically and horizontally. Formwork is used for continuous concreting of a structure along its length, including tiered in height, and for concreting in separate sections of a structure along the length of the assembled formwork. Formwork is used for the construction of canals, collectors, tanks, tunnels, aeration tanks and other structures constructed in the open.

8. Vertically movable formwork, intended for the construction of structures (tower, cooling tower, residential building) or parts thereof (elevator shaft of a residential building) and individual parts of buildings and structures one floor high (section elevator shaft, a spatial closed cell of 4 walls of the building).

9. Tunnel formwork, consisting of sections closed along the perimeter of the tunnel with supporting and forming elements. The formwork is designed for the construction of a closed loop of tunnels constructed in a closed way. Currently, tunnel formwork has found wide application for simultaneous concreting of buildings of a corridor system (hospitals, sanatoriums, rest homes, etc.), when using two sets of formwork, continuous construction of external and internal walls and ceilings is carried out immediately across the entire width of the floor of the building being constructed.

10. Permanent formwork, used in the construction of structures without stripping, with the installation of simultaneously waterproofing, cladding, insulation, etc. during the work. The specificity of the formwork is that after laying the concrete mixture into it, the formwork remains in the body of the structure, forming one whole with it (Fig. 1.5). Currently, permanent formwork is used not only for concreting individual structures, but also for constructing entire buildings. This became possible when used as formwork polystyrene foam boards thickness 50... 150 mm and density 20...25 kg/m 3, with high moisture resistance. Permanent formwork consists of factory-made formwork elements of walls and ceilings, which simultaneously perform the functions of formwork, insulation and sound insulation, as well as a base for applying finishing (textured) coatings. For permanent formwork woven can be used metal grid, reinforced concrete, reinforced concrete and asbestos concrete slabs, foam plastic slabs, glass cement, etc. This type formwork can be used in cramped working conditions and when economic feasibility its use.

11. Special formworks do not fall into the nomenclature of the main types, although they often allow the construction of similar structures. This pneumatic formwork, consisting of inflated rubberized fabric, which creates the formwork of the future spatial structure, supporting and load-bearing elements. In the working position, pneumatic formwork is supported by excess air pressure and is used for concreting thin-walled structures and curved structures.

It can also be noted non-negotiable(stationary) formwork, the purpose of which is in concreting individual places, areas and even structures for the formwork of which the use of industrial formwork is uneconomical

or technically irrational. This is disposable formwork, collected from production waste.

For concreting the walls, formwork is made the following types– small-panel, large-panel, block-shaped, block and sliding.

For concreting floors, small-panel formwork with supporting elements and large-panel formwork are used, in which the formwork surfaces and supporting elements form a single formwork block, which can be completely rearranged by a crane.

For simultaneous concreting of walls and ceilings or parts of a building, volumetric adjustable formwork is used. For the same purposes, horizontally movable formwork, including rolling formwork, is used, which can be used for concreting separately vertical, horizontal and inclined surfaces.

Combined structures are rational, in which the load-bearing

and supporting elements are made of metal, and those in contact with concrete are made of lumber, waterproof plywood, particle boards, and plastic.

7.6 According to calendar plan production of work brickwork buildings must be carried out in winter time. List the activities carried out when preparing a building for thawing (the walls of the building are laid using the freezing method)

With decreasing temperature, the hardening process of the solution slows down at t=+5°C 3-4 times; at 0°C the solution practically does not harden; with early freezing of the masonry, the final strength that it acquires at “+” temperatures does not reach the original strength and does not exceed 50% of the required strength.

When laying in winter on solutions no higher than 20°C, the following methods are used: 1)

use antifreeze additives; 2) use quick-hardening solutions;

3) electric heating of the masonry; 4) masonry reinforcement; 5) masonry in greenhouses. Features of masonry in winter: 1) reducing the opening of the plot, increasing the number of masons for the rapid construction of masonry on the entire plot at once; 2) for multi-row masonry, ligation of seams through 3 rows; 3) a supply of mortar at the workplace is allowed for 20-30 minutes of work, the mortar boxes are insulated and equipped with heating; 4) it is not allowed to lay wet and icy bricks in the structure; 5) it is not allowed to leave the solution on during breaks in work top layer masonry Activity. After the masonry freezes in the spring, it thaws, which can result in settlement of individual parts or sides of the building. After finishing the laying of each floor, it is necessary to install control slats and monitor the settlement in winter and spring periods. The most dangerous areas are equipped with temporary racks, and the floors are also unloaded from debris and snow. Free-standing pillars and piers with a height exceeding their thickness > 6 times are unfastened. Observation of masonry

carried out within 7-10 days after the onset of round-the-clock prolonged temperatures.

The standard density of laminated film is 120 g/sq.m., plywood is also produced with films of 220 and very rarely 440 g/sq.m. Number of cycles of using the same sheet laminated plywood called turnover. Remember - no manufacturer ever guarantees the turnover of the plywood it produces. Plywood takes the longest to wrap in a panel room, secured in an aluminum or steel panel, where it is additionally sealed with sealant in the seams between the profile and the plywood. Accordingly, the material used in floor formwork will have significantly lower turnover rates.

Manufacturers who claim plywood turnover, as a rule, indirectly mislead buyers. For example, SVEZA, which launched DEK-350 plywood into production, claims the high wear resistance of the film, which “ resistant to interaction with concrete", A " the ends of SVEZA Deck 350 are painted with a special water-acrylic composition" In fact, almost all manufacturers process the ends of plywood acrylic paints, because if you get carried away with the waterproofness of the ends, the sheet will begin to react in the plane, showing defects in unnecessary directions, since wood with 5-10% moisture content tends to equilibrium moisture content (at the exhibition stands of formwork manufacturers we can often observe the usual “wave”). As for abrasion, below the same advertisement on the website under DEK-350 we see the footnote “* Abrasion 350 revolutions according to the Taber test.” We suggest you figure out what it is.

The Taber test is one of the first tests that determines the quality of a coating. First, in the initial phase (IP), the number of revolutions is regulated, after which the first traces of abrasion appear, then they are regulated in the final phase (FP), when wear is 95%, and then the arithmetic average (AT) is calculated from these data. By the way, on the same Sveza website only one value is indicated without letter designation(IP, FP or AT), therefore it is not known whether it is the arithmetic mean value (AT) or whether these are the results of FP, which in turn again adds ambiguity and deprives us of the opportunity to determine the essence of the declared data.

Let's continue to figure it out. Film 120 g/m2 is 400 revolutions according to Taber test (EN 438-2), and 220 g/m2 is 750 revolutions. In principle, 120 g/m2 could consist of 40 grams of paper plus 80 grams of resin, or vice versa, or in a completely different proportion, hence the Taber results will be even more different. But based on these figures, we can conclude that the widely advertised formwork plywood with wear-resistant film DEK-350 is actually made with a film of 108 g/m2? At least a strange advantage, don’t you think? Admittedly, the plywood looks impressive, and the marking grid simplifies the cutting of plywood (for those who need it at all), but the client, making his choice in favor of this or that product, needs to understand what he is paying for, and in this case it is possible marketing fee.
11/20/2014 Press service "Stroydiscount"

Turnover is a classification indicator by which formwork is divided into single-use and inventory types. One-time formwork includes permanent structures that remain as part of the foundation or wall after the concrete has hardened. Inventory formwork is a special design designed for repeated pouring typical elements monolithic building. It is used as construction equipment and is subject to inventory accounting. How large quantity The number of fills such a structure can withstand without changing its specified characteristics, the greater the turnover of the formwork.

According to the provisions of GOST R 52085-2003, all manufactured inventory formwork, depending on the precision indicators of its production (class), must meet the following turnover requirements (see table):

Obviously, the turnover rate of the formwork will depend on the material, workmanship and operating conditions. Shields composed of wooden boards, are considered the most short-lived formworks, as they absorb moisture from concrete mortar and are severely deformed. For panel formwork, pine, spruce, birch, alder and larch boards with a thickness of 20-32 mm and a humidity of up to 25% are used. In order to obtain a high turnover rate of 8-10 cycles, lumber of grades 1 and 2 should be used for the manufacture of formwork elements. The deck side of the shield in contact with the concrete must be planed and treated with lubricant to reduce adhesion. In this case, the width of the boards on it should not exceed 150 mm.

The price of formwork boards in Russia depends on the type of wood and the processing method. Below are offers from individual lumber distributors in the country:

Turnover of laminated plywood formwork

Laminated plywood makes it possible to obtain more durable and reversible formwork structures. The main advantages of laminated plywood:

• high strength;
• gives smooth surface concrete;
• requires less supports;
• light weight;
• waste sheets can be used on the subfloor;
• The turnover rate of laminated plywood formwork can reach 50-100 cycles.

The formwork uses 18 or 21 mm sheets. Typical sheet sizes are 122x244 cm and 150x300 cm. The laminating coating can be made of melamine, phenol or PVC. It provides moisture resistance, increased density and wear resistance of the sheet surface, and resistance to adhesion.

To ensure durability and greater turnover of laminated plywood, special operating rules must be followed:

• fasten it to supports and beams with self-tapping screws on both sides;
• maintain a gap between spacers of no more than 1 m;
• When handling, be careful not to damage the laminate;
• After each dismantling, clean the surface from concrete and apply a water-repellent lubricant.

Prices for plywood depend on its brand, thickness, grade, size and manufacturer. Approximate prices for ney in Moscow are given below: