Scaffolding – description of types and structures

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In this Article: How to Make Wooden Scaffoldings types and characteristics of metal scaffolding; requirements for the construction of scaffolding (GOST); scaffolding assembly procedure; how to assemble a tower tour; prices for scaffolding and scaffolding tours; how to choose scaffolding.

Scaffolding

A thousand or two years ago, when the need arose to build buildings with a height of more than two stories, full-fledged construction equipment was also required to lift builders to this height so that they could work relatively freely on it. It was too time-consuming and troublesome to pile an embankment around the structure being erected, like the builders of Ancient Egypt – a different solution was required. This is how the first scaffolding appeared, owing its name to the tree from which it was originally created..

Like a spider web, scaffolding envelops a new building or a building in need of restoration, and workers can work on them with minimal risk to their lives. Half a century ago, not a single large construction was done without human casualties, workers were afraid to climb the shaky forests, categorically refusing to work at high altitudes. Today, working on scaffolding has become much safer, largely thanks to specially developed rules for working on them. It is worthwhile to carefully understand all the details regarding the scaffolding – so let’s do it!

Wooden scaffolding

Wood is the oldest building material and it is quite possible to build good scaffolding from it, suitable for finishing work at a low height on the scale of a private house.

Wooden scaffolding

For the scaffold, you will need: half-meter trims of a board of 150×50 mm (fifty), pieces of a thinner board (for example, 25×100 mm), a board of the required length to form a horizontal flooring. For supports (sag), you need two fairly long boards, for example, the same “fifty”.

From scraps of “fifty” overlay we knock together the triangles of the supports for the scaffold, then we sheathe them with a board of a smaller section. What considerations should be taken when choosing the size of triangular supports – sufficient space for the person standing on them and the complete exclusion of the possibility of separation from the wall / support under its own weight and the weight of the builder. For these reasons, the length of the scaffold should be in the range from 400 to 500 mm – the feet of the person standing on them should in no case sag behind the scaffold!

A line of props – they will be attached to the poles at an acute angle, so be careful with their length. The upper end of the pillars is trimmed at an angle in order to insert them inside the triangular supports, the lower part is sharpened for firm anchoring in the ground.

After bringing the scaffolding to the required position, the vertical side of the triangular supports must be nailed to the wall, without driving in the nails to the very head – upon completion of the work, they will need to be removed. We attach a ladder, one by one we raise, install and nail to the fixed supports of the flooring board – here each nail should be driven all the way.

Before starting construction and finishing work, make sure the stability of the scaffolding. Scaffolding should not be removed from wood to a height of more than seven meters!

It should be noted that in addition to wood, scaffolding can be built from grass – bamboo. In Asian countries, where this plant grows in abundance, everything is built from it. However, you should not compare the strength of bamboo with the strength of wood – its strength characteristics are an order of magnitude higher.

Metal scaffolding

Scaffolding from steel or aluminum pipes is produced industrially in two basic versions – frame and modular. Frame scaffolding includes flag, pin scaffolding and scaffolding, modular – wedge, yoke, suspended (fastening to the supporting structures of buildings) and modular (system) scaffolding. The design of scaffolding, regardless of their type, must comply with GOST 27321-87, GOST 24258-88 and stored in accordance with GOST 15150-69.

Important:before proceeding to a detailed description of metal scaffolding, it should be noted at once – they all require anchoring to the wall of the building, along or around which they are exposed! The maximum height to which it is possible to bring scaffolding without attachment to the wall of the building should not exceed 4 m and only on condition that the site on which the scaffolding is built is ideally horizontal and rammed, rainwater drainage must be organized. Failure to comply with this rule will lead to overturning or collapse of the entire structure of the scaffolding..

Frame or flag scaffolding (standard load – 200 kg / m2)

Their kit includes:side frames (with and without a ladder), stands for diagonal and horizontal fastening of side frames to each other, shoes for ground support – all these elements are made of steel. The dimensions of the frames, the installation distance between them are slightly different for each manufacturer, the construction scheme is the same.

Frame or flag scaffolding

This type of scaffold is popular for two reasons – they are cheap and easy to assemble. Fasteners of frame scaffolds are inserted into the holes intended for them and fixed by turning the “flag”. Vertically, the scaffold elements are connected by inserting the higher frame into the nest located below, without additional fixation.

Frame scaffolding is intended for masonry and finishing work on straight facades of buildings, their assembly height should not exceed 50 m (for masonry – 20-25 m, for finishing – 40 m).

Before proceeding with the installation of frame scaffolding, you should consider the scheme for their construction and the location of tiers with stairs (it is better to draw), find out the types and number of necessary elements of the scaffolding structure.

Frame scaffolding is assembled in the following order:

  1. On the finished site, the segments between the frames are measured (as a rule, the step is 3 m) and the support boards are laid out, on top – steel shoes. Frames are inserted into them, forming the first tier of scaffolding. They are exposed strictly vertically – along a plumb line, connected with braces and ties;
  2. Second tier – connection of vertical frames with the lower tier, fixing them with diagonal / horizontal ties (level and plumb line are used). For the future laying of decking, horizontal ribs of the girders are exposed. From the first to the final (highest) tier, diagonal ties must be installed in a checkerboard pattern, i.e. their location should not be the same as vertically adjacent tier sections;
  3. Installation of ladder structures located at an angle (workers can also climb vertical ladders built into the frames, but this is not convenient and complicates the course of work). Inclined stairs are exposed as the tiers rise;
  4. Mandatory fastening of the erected scaffold structure to the building using hooks with bushings, plug anchors, securely connecting the scaffold frames to the wall (check!). Fastening the scaffolding with the wall in a checkerboard pattern, step – 4 m;
  5. Removing the scaffolding tiers to the required height, repeating the operations described above (starting from the 2nd tier);
  6. At the ends of the collected scaffolding, end ties-rods are set, along the entire length of the tiers, in those sections where there are no diagonal ties – establish longitudinal (horizontal) ties, acting as a fence.

Dismantling the scaffolding is carried out in the reverse order, from top to bottom..

Frame scaffolding widely presented on the construction market is offered at an average price of 170 rubles. per m2, their monthly rent will cost 60 rubles. per m2.

Pin scaffolding (standard load – 200 kg / m2)

In terms of their design and assembly technique, these scaffolds are as simple as frame ones – their horizontal elements are fastened by inserting pins into hollow eye tubes welded to the vertical posts. The lower supports of the frame struts are inserted into the shoes, each new level is assembled in stages, the diagonally installed braces give greater rigidity to the scaffolding.

Pin scaffolding

Pin scaffolds are built up to 40 meters in height, they are used mainly in masonry and rarely in finishing work. With all its simplicity and reliability, this type of scaffolding can be combined with yoke scaffolding, which makes it possible to build complex frame schemes.

The average market value of forests of this type is 550 rubles. per m2, rent – 100 rubles. per m2 per month. The reason for the higher cost in comparison with frame (flag) scaffolding is the ability to carry large loads, since in their design, steel pipes with a significant wall thickness are used (for example, LSh 100 – the diameter of the steel pipe is 57 mm, the wall is 3.5 mm).

Vishnev scaffolding (standard load – 200-250 kg / m2)

The frames of these scaffolds are not installed vertically, but horizontally during assembly. They connect the vertical posts just above the base shoes, and in each new tier they serve as a support for the deck. Strengthening the structure of Vishnev scaffolding does not require diagonal ties, this is the only type of scaffolding that does not need them.

Vishnev scaffolding

Vishnev scaffolding ladders are not built into the frame, they are an independent element installed at an angle inside the scaffold structure. Ladders and railing frames are equipped with pins, which are inserted into the lugs of the posts (similar to fastening ties at pin scaffolds).

Vishnev’s forests are intended for restoration and finishing works at a height of up to 40 m, both inside and outside buildings. Starting from the second tier, the racks of these scaffolds must be fixed on the wall, horizontally in 6 m increments, vertically – on each tier (anchors, crutches and steel wire, braces and brackets are used).

Their average cost is 300 rubles. per m2, monthly rental price – 80 rubles. per m2.

Tower-round (standard load – 200 kg / m2)

This design is a kind of compromise on the combination of “price” and “need”. Any building periodically requires repairs of various levels of complexity, both complete finishing and fragmentary “cosmetics”. And if up to a certain height, say, up to 5-8 meters, it is somehow possible to do with ladders, then a more stable and spacious working platform will be needed at a higher height. Scaffolding around the perimeter of a building is expensive. And collecting / dismantling forests again and again, moving to a new place each time is not easy and takes time. The optimal solution here is a tour tower.

Tower tour

The design of any tower-tours is the same – it is assembled from ready-made frames, equipped with a ladder. Wheels are attached to the base, they can be raised above the ground level by a few millimeters if the screw supports fixed on the lower frame are extended to the maximum, acting on the principle of a jack. When the tiers are brought to a height of more than 4 m, additional (standard) spacers are attached to the frames of the first tier. Depending on the model of the tower, when lifting the tiers to 2/3 of the maximum height, it is necessary to fasten it to the wall of the building with anchors or brackets. The tower is equipped with two or three horizontal platforms, the upper one is equipped with a hinged hatch for lifting / lowering.

Tower-tours can have a height of 4 to 21 meters, depending on the number of tiers, each of which is 2 m high (it would be difficult to lift frames of greater length). Its operation will require a firm and level platform that does not have any slopes..

The order of assembly of the tower-tour:

  1. A frame with wheels is placed on the platform, screw supports are extended, wooden supports are preliminarily placed under them;
  2. Connect the side frames to the base frame, fix them to horizontal braces and pull them with diagonal stiffeners, lay and fix the flooring, connect the side supports;
  3. Insert the frames of the next tier into the pins of the side frames, connect them with horizontal and vertical ties – each new tier is assembled according to this scheme. As you climb to the height, install the side struts, put a wooden stand under each of them;
  4. On the upper section, set up and fix the flooring, a safety fence, vertical and diagonal ties – the fence should be brought out to a height of at least one meter from the flooring.

Dismantling of the tower-round is carried out from the upper tier in the reverse order to the assembly stages.

The price of a tour tower depends on its model, material of execution (steel or aluminum pipe), the number of tiers. Steel towers cost an average of 12,000 rubles. (height 4.2 m), aluminum – 44,000 rubles. (height 4.9 m). It should be noted that it will not be possible to buy additional elements of new tiers for an already purchased tour tower – its design is designed for a certain lifting height, adding sections will increase the load on the base frame and reduce its strength.

Wedge scaffolding (standard load – 200-300 kg / m2)

These scaffolds are more complex than those described above – their constituent elements are fixed with steel wedges driven in / out with a hammer. This type of fastening greatly increases the reliability of the scaffolding, they are capable of carrying a greater load than frame or pin scaffolding.

Wedge scaffolding

The shape of the wedge, which connects the posts and girders of the wedge scaffolds, does not allow spontaneous wedging, and the flange locks on the posts are equipped with eight holes – for building scaffolding of the required spatial shape. When dismantling the scaffolding, the wedges removed from the joints are inserted into the special holes with which the racks are equipped.

The maximum height to which wedge scaffolding can be raised is 40 m. They are used both in construction and finishing works, including high-rise ones, and for temporary structures for public use – visual stands and concert scenes, stair descents. This type of scaffolding is popular with ship / aircraft manufacturers.

Price per m2 wedge scaffolding averages 200 rubles, rent of m2 will cost 80 rubles. per month.

Clamp scaffolding (standard load – 200-250 kg / m2)

One of the first types of scaffolding. All prefabricated elements of these scaffoldings are connected by clamps – rotary (repeated) and blind. They are difficult to assemble, but the height to which they are brought out is two times higher than the capabilities of other types of scaffolding – 80 m. Racks and crossbars are inserted into clamps, which are then tightened with threaded bolts.

Clamp scaffolding

This type of scaffolding gives access to any spatial structure, be it domes or complex architectural protrusions, which create “blind spots” around the perimeter for frame, pin or wedge scaffolding. The possibility of building tiers of any height, combining with any types of metal scaffolding – all this justifies their rather high price and complex assembly.

It should be noted that clamped scaffolding is produced in two versions, differing in profile diameter: “professional” – a steel pipe with a cross section of 57 mm is used; “Lightweight” – pipe diameter 48 mm. As a rule, when assembling clamp scaffolds, both standard sizes of racks are used – 2 m and 4 m, alternating during installation. Longitudinal ties are also of two sizes (3.6 and 5 m) and are also alternating.

Yoke scaffolding cost about 450 rubles. per m2, rental price – 75 rubles / m2/month.

Suspended scaffolding (standard load – 200 kg / m2)

The building itself (its floors) serves as a support for the scaffolding of this structure, i.e. their lower tier does not touch the ground. In cases where the partial or complete lack of space near the building does not allow the installation of any other version of scaffolding, suspended scaffolding is indispensable. Interference in the form of extensions, a significant height of the object, architectural elements of weak strength, the need to be surrounded by forests of the entire perimeter of the building, the simultaneous conduct of communication and landscape works (tight deadlines) – all these are tasks for suspended scaffolding. They are used for finishing and restoration work..

Suspended scaffolding

The outwardly protruding elements of the suspended scaffolding reliably hold the consoles (material – channel No. 10), fixed in the spacer between the floors, they are connected by cross-members and ties on clamps. In other words, with the exception of the support brackets, the suspended scaffolding is otherwise a variation of the clamped scaffolding (1.5 “cross members and braces, 2” posts, 2.5 mm steel pipe wall).

Each new tier is connected to the consoles on the floor of the building that coincides with it and to the lower tier, the vertical posts must be anchored to the walls (step 4 m).

Only part of the suspended scaffolding can be purchased ready-made – the one that forms the outer tiers, i.e. elements of clamp scaffolding. Spacers-brackets are calculated and manufactured for a specific object and cannot be unified due to structural differences between different buildings – they must be ordered additionally. Suspended scaffolding price is only negotiable.

Modular (system) scaffolding (standard load – 200 kg / m2)

They allow you to form a structure of almost any shape that can bypass any protrusions, repeat the rounded or angular outlines of an object, the facade repair of which is necessary. Their elements can be connected by wedge-disk (disc) or cup-lock (cup-lock).

Modular scaffolding

In the first case, the crossbars and scaffold ties, equipped with a fork-shaped lock, are inserted into the disk lock of the vertical support and locked in it with a wedge (the locking element of some ties is movable, i.e. it can be fixed at the required angle).

The scaffolding crossbars with cup-lock connection are attached as follows: their posts are equipped with steel cups welded at a certain height, T-shaped locks of the crossbars are placed in them, and the lock is fixed on top by a wedge nut.

Elements of modular (system) scaffolding are made of steel pipes (d – 48 mm, wall thickness – 3.5 mm) and coated with a zinc layer (hot-dip galvanized). Supports for them are of three options – ordinary (square base and a connecting pipe section in the center), screw (according to the jack principle) and wheeled. The maximum lifting height of the tiers is 60 m, starting from the 3rd tier it is necessary to fasten them to the wall with anchors.

Modular (system) scaffolding is used in high-rise work on objects of complex geometry, in formwork, in the creation of temporary spatial structures, such as concert and demonstration sites.

This type of forest is quite expensive – its elements are produced outside Russia, mainly in the EU countries. The average cost of modular scaffolding is 3,000 rubles. per m2 (depending on the manufacturer and execution), lease issues must be negotiated with the owners of this type of forest personally.

What type of scaffolding to choose

The solution to this issue is for the purpose of their application. It is necessary to analyze the scope of the upcoming work, their urgency, the presence / absence of sites for the placement of forests. Framed scaffolding, for example, is great for masonry and finishing work at low altitudes, they are cheap and unpretentious. For masonry at a higher height, yoke or pin scaffolds will be required – they have a higher carrying capacity. By the way, the normative carrying capacity given above for each type of scaffolding is the minimum, i.e. depending on the specific model of the scaffolding, their carrying capacity may be higher – this indicator, inter alia, depends on the thickness and diameter of the steel elements, the scaffolding scheme.

Clamp scaffolds are indispensable for high-altitude work and for objects of complex geometry, however, this type of scaffolding has a major flaw – over time, the tightening bolts on the clamps rust, losing strength and ability to fasten. Therefore, you only need to choose clamps with a galvanized layer – they will last longer and without interfering with work. When renting clamp scaffolds, in particular, pay attention to the wear of the clamp fasteners, the degree of deformation of the struts at the connection points (they are deformed by the clamps).

Having opted for wedge scaffolds, please note that they cannot be purchased by quadrature – first, prepare a draft of the necessary scaffolding design, coordinate it with the supervising government agencies. And only after that buy the necessary elements of wedge-shaped scaffolding according to the prepared list.

A high-quality calculation of their needs will help significantly save on scaffolding, in addition, you can combine different types of scaffolding, resulting in access to working surfaces (for example, combined scaffolding from frame and clamp).

The main thing when choosing scaffolding, in addition to cost and versatility, will be their safety for workers – reliable attachment points, comfortable ladders, the obligatory presence of safety sides. For each assembly, it is necessary to test the strength of the scaffolding, without relying on chance.

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