Construction is an area for which we work tirelessly chemical industry, creating new alloys and materials for the production of various products. One of the most important and promising achievements in this area for last years we can name the results associated with work on such a composite material as fiberglass. Many engineers and builders call it the material of the future, since it has managed to surpass in its qualities many metals and alloys, including alloy steel.
What is fiberglass? This is a composite that has two components: a reinforcing and a binding base. The first one is fiberglass, the second one is different in its own way. chemical composition resin. Variations in the amount of both allow you to make fiberglass resistant to the conditions of almost any environment. But it should be understood that there is no universal type of fiberglass; each of them is recommended for use in certain operating conditions.
Fiberglass is interesting to designers because finished products made from it appear simultaneously with the material itself. This feature gives a lot of scope for imagination, allowing you to produce a product with individual physical and mechanical characteristics according to the client’s specified parameters.
One of the most common building materials The grating is made from fiberglass. Unlike steel decking, it is produced by casting, which gives it such characteristics as low thermal conductivity, isotropy, and of course, like steel materials, strength and durability.
Stair steps are made from fiberglass grating, however, the entire structure is also made from fiberglass parts: racks, handrails, supports, channels.
Of course, such stairs are very durable, they are not afraid of corrosion and exposure to chemicals. They are easy to transport and install. Unlike metal structures, several people are enough to install them. An additional advantage is the ability to choose colors, which increases visual appeal object.
Gangways made of fiberglass have become very popular. Their reliability is due to the same unique characteristics the composite we are describing. Pedestrian areas equipped with fiberglass gangways do not require special maintenance; their operational capabilities are much higher than those of the same type of metal structures. It has been proven that the service life of fiberglass is much longer than the latter and amounts to more than 20 years.
Another highly effective offering is the fiberglass handrail system. All railing parts are very compact and easy to carry. hand assembled. In addition, the client has many variations of the finished design, as well as the opportunity to implement his own project.
Due to the dielectric properties of fiberglass, cable channels are made from it. The isotropy of this material increases the demand for products planned for use in facilities sensitive to electromagnetic vibrations.
In general, it can be noted that the range of fiberglass products is quite wide. Working with it, builders and designers can realize the most fantastic ideas. All designs offered by our company are reliable and durable. The quality of fiberglass determines its relatively high price, but at the same time it is the optimal ratio of the advantages of this material and the demand for it. And at the same time, it is important to understand that the costs of its purchase will pay off in the future due to the reduction in costs of its transportation, installation and subsequent maintenance.
Basic Concepts
Fiberglass - a system of glass threads knitted with thermosets (irreversible hardening resins).
Mechanisms of Strength—Adhesion between a Single Fiber and a Polymer (resin) adhesion depends on the degree of cleaning of the fiber surface from the sizing agent (polyethylene waxes, paraffin). The sizing is applied at the fiber or fabric manufacturing plant to prevent delamination during transport and technological operations.
Resins are polyester, characterized by low strength and significant shrinkage during hardening, this is their disadvantage. Plus - fast polymerization, unlike epoxides.
However, shrinkage and rapid polymerization cause strong elastic stresses in the product and over time the product warps, the warping is insignificant, but on thin products it gives unpleasant reflections of a curved surface - see any Soviet body kit for VAZs.
Epoxies hold their shape much more accurately, are much stronger, but are more expensive. The myth about the cheapness of epoxies is due to the fact that the cost of domestic epoxy resin is compared with the cost of imported polyester resin. Epoxies also benefit from heat resistance.
The strength of fiberglass - in any case, depends on the amount of glass by volume - the most durable with a glass content of 60 percent, however, this can only be obtained under pressure and temperature. IN "cold conditions" it is difficult to obtain durable fiberglass.
Preparation of glass materials before gluing.
Since the process consists of gluing fibers together with resins, the requirements for the fibers being glued are exactly the same as for gluing processes - thorough degreasing, removal of adsorbed water by annealing.
Degreasing, or removal of coupling agent, can be done in BR2 gasoline, xylene, toluene, and their mixtures. Acetone is not recommended due to the binding of water from the atmosphere and "getting wet» fiber surface. As a method of degreasing, you can also use annealing at a temperature of 300-400 degrees. In amateur conditions, this can be done like this: rolled fabric is placed in a workpiece from ventilation pipe or galvanized drainage and is cut into a spiral from an electric stove placed inside the roll; you can use a hair dryer to remove paint, etc.
After annealing, glass materials should not be exposed to air, since the surface of the fiberglass absorbs water.
Some words "craftsmen"The possibility of gluing without removing the sizing agent evokes a sad smile - no one would think of gluing glass over a layer of paraffin. Tales about how "resin dissolves paraffin” is even funnier. Spread the glass with paraffin, rub it, and now try to glue something to it. Draw your own conclusions))
Sticking.
The separating layer for the matrix is the best polyvinyl alcohol in water, applied by spray and dried. It gives a slippery and elastic film.
You can use special waxes or wax mastics silicone-based, but you should always make sure that the solvent in the resin does not dissolve the separating layer by first trying it on something small.
When gluing, lay layer upon layer, rolling with a rubber roller, squeezing out excess resin, remove air bubbles by piercing with a needle.
Be guided by the principle - excess resin is always harmful - resin only glues glass fibers, but is not a material for creating molds.
if a high-precision part, such as a hood cover, it is advisable to introduce a minimum of hardener into the resin and use heat sources for polymerization, for example, an infrared lamp or a household "reflector».
After hardening, without removing from the matrix, it is very desirable to heat the product evenly, especially at the stage "gelatinization» resin. This measure will relieve internal stress and the part will not warp over time. Regarding warping - I’m talking about the appearance of glare and not about changing sizes; sizes can change by only a fraction of a percent but still give strong glare. Pay attention to plastic body kits made in Russia - none of the manufacturers "is bothering“The result is summer, it stood in the sun, in winter there were a couple of frosts and... everything looked crooked... although the new one looked great.
In addition, with constant exposure to moisture, especially in places where there are chips, the fiberglass begins to come out, and gradually, being wetted with water, it simply fringes; sooner or later, water penetrating into the thickness of the material peels off the glass threads from the base (glass adsorbs moisture very strongly)
in a year.
The sight is more than sad, well, you see such products every day. What is made of steel and what is made of plastic is immediately obvious.
By the way, prepregs sometimes appear on the market - these are sheets of fiberglass already coated with resin; all you have to do is put them under pressure and heat them - they will stick together into beautiful plastic. But the technical process is more complicated, although I have heard that a layer of resin with a hardener is applied to prepregs and excellent results are obtained. I didn't do that myself.
These are the basic concepts about fiberglass, make the matrix in accordance with common sense from any suitable material.
I use dry plaster "rotband"It is processed perfectly, holds the size very accurately, after drying from water it is impregnated with a mixture of 40 percent epoxy resin with a hardener - the rest is xylene, after the resin has cured, such forms can be polished or. very durable and fit perfectly.
How to peel off a product from a matrix?
For many, this simple operation causes difficulties, even to the point of destruction of the form.
It’s easy to peel off - make a hole or several in the matrix before gluing, and seal it with thin tape. After making the product, blow compressed air into these holes one by one - the product will peel off and be removed very easily.
Again, I can say what I use.
Resin - ED20 or ED6
hardening agent - polyethylene polyamine, also known as PEPA.
Thixotropic additive - aerosil (at By adding it, the resin loses its fluidity and becomes jelly-like, very convenient) is added according to the desired result.
The plasticizer is dibutyl phthalate or castor oil, about a percent or a quarter of a percent.
Solvent - orthoxylene, xylene, ethyl cellosolve.
resin filler for surface layers - aluminum powder (hides fiberglass mesh)
fiberglass - asstt, or fiberglass mat.
Auxiliary materials - polyvinyl alcohol, silicone Vaseline KV
Thin polyethylene film is very useful as a separating layer.
It is useful to evacuate the resin after stirring to remove any bubbles.
I cut the fiberglass into the required pieces, then roll it up, place it in a pipe and calcinate the whole thing with a tubular heating element placed inside the roll, it calcinates overnight - it’s so convenient.
Yes, and here's another.
Do not mix epoxy resin with hardener in one container in an amount of more than 200 grams. It will heat up and boil in no time.
Express control of the results - on the test piece, when breaking, the glass threads should not stick out - the fracture of the plastic should be similar to the fracture of plywood.
break any plastic from which the body kit is made or pay attention to the broken one - solid rags. This is the result "no» bond between glass and polymer.
Well, little secrets.
It’s very convenient to correct devections such as scratches or sinkholes: apply a drop of epoxy resin to the sink, then stick tape on top as usual (ordinary, transparent), level the surface using the highlights using your fingers or applying something elastic; after hardening, the adhesive tape comes off easily and gives a mirror-like surface. No processing is required.
Solvent reduces the strength of the plastic and causes shrinkage in finished product.
Its use should be avoided if possible.
aluminum powder is added only to the surface layers - it reduces shrinkage very much, the mesh characteristic of plastics appears to me then nothing, the amount reaches the consistency of thick sour cream.
Epoxies are processed worse than polyesters and this is their disadvantage.
the color after adding aluminum powder is not silver but metallic grey.
ugly in general.
The metal fastener glued into the plastic must be made of aluminum alloys or titanium - because... A very thin layer of silicone sealant is applied to the embedded product, and fiberglass fabric, previously well annealed, is pressed against it. The fabric should stick but should NOT be soaked through. after 20 minutes, this fabric is moistened with resin WITHOUT SOLVENT and the remaining layers are glued to it. This "combat "technology As a silicone sealant, we used the Soviet KLT75 vibration-resistant compound, which is heat-resistant, frost-resistant, and resistant to salt water. Preparing the metal surface - wash the aluminum alloy in a clean solvent. pickle in a mixture of washing soda and washing powder, heating the solution to a boil; if possible, then in a weak alkali, for example a 5% solution of caustic potassium or soda, and dry with heat. warm up to 200-400 degrees. After cooling, glue in as quickly as possible.
The article talks about what properties fiberglass has and how applicable it is in construction and in everyday life. You will find out what components are needed to make this material and their cost. The article provides step by step videos and recommendations for the use of fiberglass.
Since the discovery of the effect of rapid petrification of epoxy resin under the action of an acid catalyst, fiberglass and its derivatives have been actively introduced into household products and machine parts. In practice, it replaces or supplements exhaustible natural resources - metal and wood.
The operating principle underlying the strength of fiberglass is similar to reinforced concrete, and in appearance and structure it is closest to the reinforced layers of modern “wet” facade finishing. Typically, the binder is composite, gypsum or cement mortar- tends to shrink and crack, not holding the load, and sometimes not even maintaining the integrity of the layer. To avoid this, a reinforcing component is introduced into the layer - rods, meshes or canvas.
The result is a balanced layer - the binder (in dried or polymerized form) works in compression, and the reinforcing component works in tension. From such layers based on fiberglass and epoxy resin, you can create three-dimensional products, or additional reinforcing and protective elements.
Reinforcing component*. For the manufacture of household and auxiliary building elements, three types of reinforcing material are usually used:
* The types of reinforcement described are also used for other work, but the product data sheet usually indicates their compatibility with epoxy resin.
Table. Prices for fiberglass (using the example of Intercomposite products)
Astringent. This is an epoxy solution - resin mixed with a hardener. Separately, the components can be stored for years, but when mixed, the composition hardens from 1 to 30 minutes, depending on the amount of hardener - the more of it, the faster the layer hardens.
Table. The most common grades of resin
Popular hardeners:
An additional chemical component is a lubricant, which is sometimes applied to protect surfaces from penetration of epoxy (for mold lubrication).
In most cases, the master studies and selects the balance of components independently.
In private, this material is most often used in three cases:
To do this, you will need a fiberglass sleeve and a high-strength resin grade (ED-20 or equivalent). The technical process is described in detail in this article. It is worth noting that carbon fiber is much stronger than fiberglass, which means that the latter is not suitable for repairs percussion instrument(hammers, axes, shovels). At the same time, it is quite possible to make a new handle or handle for equipment from fiberglass, for example, the wing of a walk-behind tractor.
Helpful advice. You can improve your tool with fiberglass. Wrap the handle of a working hammer, axe, screwdriver, saw with impregnated fiber and squeeze it in your hand after 15 minutes. The layer will ideally take the shape of your hand, which will significantly affect the ease of use.
The tightness and chemical resistance of fiberglass allows you to repair and seal the following plastic products:
Repair using fiberglass - step-by-step video
“Homemade” fiberglass has one irreplaceable property - it is accurately processed and holds rigidity well. This means that from canvas and resin you can restore a hopelessly damaged plastic part, or make a new one.
Fiberglass in liquid form has excellent adhesion to porous materials. In other words, it adheres well to concrete and wood. This effect can be realized by installing wooden lintels. A board on which liquid fiberglass is applied acquires an additional 60-70% strength, which means that a board twice as thin can be used for a lintel or crossbar. If strengthened with this material door frame, it will become more resistant to loads and distortions.
Another method of application is sealing stationary containers. Reservoirs, stone cisterns, swimming pools covered with fiberglass on the inside are becoming increasingly positive properties plastic dishes:
At the same time, the creation of such a coating will cost about 25 USD. e. for 1 sq. m. Real tests of products from one of the private mini-factories eloquently speak about the strength of the products.
Video: testing fiberglass
Of particular note is the possibility of repairing the roof. With a properly selected and applied epoxy compound, you can repair slate or tiles. With its help, you can model complex translucent structures made of plexiglass and polycarbonate - canopies, street lamps, benches, walls and much more.
As we found out, fiberglass is becoming a simple and understandable repair and construction material that is convenient to use in everyday life. With developed skill, you can create interesting products from it right in your own workshop.
Fiberglass profiles are visually known, standard profiles designed for various applications in construction and design, made of fiberglass.
Having the same external parameters as profiles from traditional materials, profiled fiberglass, has a number of unique characteristics.
Fiberglass profiles have one of the highest strength-to-weight ratios of any structural product, as well as excellent corrosion resistance. The products are highly resistant to ultraviolet radiation, a wide range of operating temperatures (-100°C to +180°C), as well as fire resistance, which allows the use of this material in various areas of construction, especially when operating in areas dangerous voltage, and in the chemical industry.
The profiles are manufactured using the pultrusion method, a feature of the technology that This consists of continuous drawing of roving made of filament threads, pre-impregnated with a multicomponent system based on binders of various resins, hardeners, thinners, fillers, and dyes.
The fiberglass is impregnated with resin and then passed through a heated die of the desired shape, in which the resin hardens. The result is a profile of a given shape. Fiberglass profiles are reinforced on the surface with a special non-woven fabric (mat), thanks to which the products acquire additional rigidity. The profile frame is covered with fleece impregnated with epoxy resin, which makes the product resistant to ultraviolet radiation.
A special feature of pultrusion technology is the production of straight products with a constant cross-section along the entire length.
The cross-section of the fiberglass profile can be any, and its length is determined in accordance with the wishes of the customer.
FRP structural profile comes in a wide range of shapes including I-beam, equal-flange, equal-flange, square pipe, a round pipe, as well as a corner for laying when concreting in a variety of sizes, which can be used instead of a traditional metal corner, which is subject to rapid destruction from rust.
Most often, a fiberglass profile is made of orthophthalic resin.
Depending on the operating conditions, it is possible to produce profiles from other types of resins:
- - vinylester resin: intended for use in conditions where high corrosion resistance is required from the material;
- epoxy resin: has special electrical properties, making products made from it optimal for use in hazardous voltage areas;
- acrylic resin: products made from it have low smoke emission in case of fire.
In our company you can purchase standard and non-standard fiberglass profiles of any size according to your wishes and requirements. The main list of fiberglass profiles is as follows:
Corner
The dimensions of this material may vary. They are used in almost all fiberglass structures. Structurally, they are used in fiberglass staircases, lighting installations, in the bases of bridges, and transitions made of fiberglass flooring.
Corner symbol:
a – width,
b – height,
c – thickness.C-profile (C-profile)
Due to their corrosion resistance, fiberglass C-profiles are used primarily in the chemical industry.
Symbol C-profile:
a – width,
b – height,
c – opening width,
d – thickness.Fiberglass beam
Can be used either as a part of an integrated solution, or as an independent structure (fiberglass railings).
Beam symbol:
a – width,
b – height.I-beams
Fiberglass I-beams are most often used as load-bearing structures that span large spans and are capable of carrying various loads. I-beams are optimal constructive solution as a base for fiberglass flooring, staircases, lighting installations, bridges, etc.
I-beam symbol:
a – width,
b – height,
c – thickness.Profile "Hat"
Used as an insulating profile mainly in the electronics industry.
Profile symbol:
a – width,
b – size of the upper part of the profile,
c – thickness.Rectangular pipes
The products are capable of bearing both vertical and horizontal loads.
Pipe designation:
a – width,
b – height,
c – wall thickness.Fiberglass rod is used as fiberglass antenna, sun umbrellas, profiles in model making, etc.
Bar symbols:
a – diameter.Taurus
They are used as additional structures in fiberglass walkways, stages, load-bearing surfaces, etc.
Brand symbols:
a – height,
b – width,
c – thickness.Round pipe
Such fiberglass pipes are not used in structures with internal pressure.
Pipe symbols:
a – outer diameter,
b – internal diameter.Intended for use as the basis of a structure, such as a staircase, staircase or work platform, gangway.
Channel symbols:
a – width,
b – height,
c/d – wall thickness.Z-profile (Z-profile)
Designed for use in gas cleaning facilities.
Profile legend:
a – width of the upper part of the profile,
b – height,
c – width of the lower part of the profile.
The dimensions of this material may vary. They are used in almost all fiberglass structures.
In foreign construction, the main application of all types of fiberglass is translucent fiberglass, which is successfully used in industrial buildings in the form of sheet elements with a corrugated profile (usually in combination with corrugated sheets of asbestos cement or metal), flat panels, domes, and spatial structures.
Translucent enclosing structures serve as a replacement for labor-intensive and low-cost window units and skylights in industrial, public and agricultural buildings.
Translucent fencing found wide application in walls and roofs, as well as in elements of auxiliary structures: canopies, kiosks, fences of parks and bridges, balconies, flights of stairs and etc.
In cold enclosures industrial buildings Corrugated sheets of fiberglass are combined with corrugated sheets of asbestos cement, aluminum and steel. This makes it possible to use fiberglass in the most rational way, using it in the form of separate inclusions in the roof and walls in quantities dictated by lighting considerations (20-30% of the total area), as well as fire resistance considerations. Fiberglass sheets are attached to the purlins and half-timbers with the same fasteners as sheets of other materials.
IN Lately In connection with the decline in prices for fiberglass and the production of self-extinguishing material, translucent fiberglass began to be used in the form of large or continuous areas in the enclosing structures of industrial and public buildings.
Standard sizes of corrugated sheets cover all (or almost all) possible combinations with profile sheets made of other materials: asbestos cement, clad steel, corrugated steel, aluminum, etc. For example, the English company Alan Blun produces up to 50 standard sizes of fiberglass, including profiles, adopted in the USA and Europe. The assortment is almost as large profile sheets made of vinyl plastic (Merly company) and plexiglass (ICI company).
Along with translucent sheets, consumers are also offered complete parts for their fastening.
Along with translucent fiberglass plastics, in recent years in a number of countries rigid translucent vinyl plastic, mainly in the form of corrugated sheets, has also become increasingly widespread. Although this material is more sensitive to temperature fluctuations than fiberglass, has a lower elastic modulus and, according to some data, is less durable, it nevertheless has certain prospects due to a wide raw material base and certain technological advantages.
Domes made of fiberglass and plexiglass are widely used abroad due to high lighting characteristics, low weight, relative ease of manufacture (especially plexiglass domes), etc. They are produced in spherical or pyramidal shapes with a round, square or rectangular outline in plan. In the USA and Western Europe Mostly single-layer domes are used, but in countries with colder climates (Sweden, Finland, etc.) - two-layer ones with an air gap and a special device for draining condensate, made in the form of a small gutter around the perimeter of the supporting part of the dome.
The area of application of translucent domes is industrial and public buildings. Dozens of companies in France, England, the USA, Sweden, Finland and other countries are engaged in their mass production. Fiberglass domes typically come in sizes from 600 to 5500 mm, And from plexiglass from 400 to 2800 mm. There are examples of the use of domes (composite) significantly large sizes(to 10 m and more).
There are also examples of the use of reinforced vinyl plastic domes (see Chapter 2).
Translucent fiberglass, which until recently was used only in the form of corrugated sheets, is now beginning to be widely used for the manufacture of large-sized structures, especially wall and roof panels of standard sizes that can compete with similar structures made from traditional materials. There is only one American company, Colwall, which produces three-layer translucent panels up to b m, has used them in several thousand buildings.
Of particular interest are the developed fundamentally new translucent panels of a capillary structure, which have increased thermal insulation ability and high translucency. These panels consist of a thermoplastic core with capillary channels (capillary plastic), covered on both sides with flat sheets of fiberglass or plexiglass. The core is essentially a translucent honeycomb with small cells (0.1-0.2 mm). It contains 90% solids and 10% air and is made mainly from polystyrene, less often plexiglass. It is also possible to use polocarbonate, a thermoplastic with increased fire resistance. The main advantage of this transparent design is its high thermal resistance, which provides significant savings on heating costs and prevents the formation of condensation even at high air humidity. An increased resistance to concentrated loads, including impact loads, should also be noted.
The standard dimensions of capillary structure panels are 3X1 m, but they can be manufactured up to 10 m long m and width up to 2 m. In Fig. Figure 1.14 shows the general view and details of an industrial building, where panels of a capillary structure measuring 4.2X1 are used as light barriers for the roof and walls m. The panels are laid along the long sides on V-shaped spacers and joined at the top using metal overlays with mastic.
In the USSR, fiberglass was found in building structures very limited use (for individual experimental structures) due to its insufficient quality and limited range
(see chapter 3). Basically, corrugated sheets with a small wave height (up to 54 mm), which are used mainly in the form of cold fencing for buildings of “small forms” - kiosks, canopies, light canopies.
Meanwhile, as feasibility studies have shown, the greatest effect can be achieved by using fiberglass in industrial construction as translucent fences for walls and roofs. This eliminates expensive and labor-intensive lantern add-ons. The use of translucent fencing in public construction is also effective.
Fences made entirely of translucent structures are recommended for temporary public and auxiliary buildings and structures in which the use of translucent plastic fencing is dictated by increased lighting or aesthetic requirements (for example, exhibition, sports buildings and structures). For other buildings and structures total area light openings filled with translucent structures are determined by lighting calculations.
TsNIIPromzdanii, together with TsNIISK, Kharkov Promstroyniproekt and the All-Russian Research Institute of Fiberglass and Fiberglass, has developed a number of effective structures for industrial construction. The simplest design is translucent sheets laid along the frame in combination with corrugated sheets of non-porous
transparent materials (asbestos cement, steel or aluminum). It is preferable to use shear wave fiberglass in rolls, which eliminates the need to join sheets widthwise. In case of longitudinal waves, it is advisable to use sheets of increased length (for two spans) to reduce the number of joints above the supports.
Covering slopes in the case of a combination of corrugated sheets made of translucent materials with corrugated sheets of asbestos cement, aluminum or steel should be assigned in accordance with the requirements,
Presented for coatings made of non-transparent corrugated sheets. When constructing coverings entirely of translucent wavy sheets, the slopes should be at least 10% in the case of joining sheets along the length of the slope, 5% in the absence of joints.
The overlap length of translucent corrugated sheets in the direction of the slope of the coating (Fig. 1.15) should be 20 cm with slopes from 10 to 25% and 15 cm with slopes greater than 25%. In wall fences, the overlap length should be 10 cm.
When applying such solutions, serious attention must be paid to the arrangement of fastenings of sheets to the frame, which largely determine the durability of structures. The corrugated sheets are fastened to the purlins with bolts (to steel and reinforced concrete purlins) or screws (to wooden purlins) installed along the crests of the waves (Fig. 1.15). Bolts and screws must be galvanized or cadmium plated.
For sheets with wave sizes 200/54, 167/50, 115/28 and 125/35, fastenings are placed on every second wave, for sheets with wave sizes 90/30 and 78/18 - on every third wave. All extreme wave crests of each corrugated sheet must be secured.
The diameter of bolts and screws is taken according to calculation, but not less than 6 mm. The diameter of the hole for bolts and screws should be 1-2 mm Larger than the diameter of the mounting bolt (screw). Metal washers for bolts (screws) must be bent along the curvature of the wave and equipped with elastic sealing pads. The diameter of the washer is taken by calculation. In places where corrugated sheets are attached, wooden or metal pads are installed to prevent the wave from settling on the support.
The joint across the direction of the slope can be made using bolted or adhesive joints. For bolted connections, the overlap length of corrugated sheets is taken to be no less than the length of one wave; bolt pitch 30 cm. Bolted joints of corrugated sheets should be sealed with tape gaskets (for example, elastic polyurethane foam impregnated with polyisobutylene) or mastics. For adhesive joints, the length of the overlap is calculated, and the length of one joint is no more than 3 m.
In accordance with the guidelines adopted in the USSR for capital construction The research focuses on large-sized panels. One of these structures consists of a metal frame, working for a span of 6 m, and corrugated sheets supported on it, working for a span of 1.2-2.4 m .
The preferred option is filling with double sheets, as it is relatively more economical. Panels of this design size 4.5X2.4 m were installed in an experimental pavilion built in Moscow.
The advantage of the described panel with a metal frame is the ease of manufacture and the use of materials currently produced by industry. However, three-layer panels with skins made of flat sheets, having increased rigidity, better thermal properties and requiring minimal metal consumption.
The low weight of such structures allows the use of elements of considerable size, however, their span, as well as corrugated sheets, is limited by maximum permissible deflections and some technological difficulties (the need for large-sized press equipment, joining sheets, etc.).
Depending on the manufacturing technology, fiberglass panels can be glued or integrally molded. Glued panels are made by glueing together flat skins with an element of the middle layer: ribs made of fiberglass, metal or antiseptic wood. For their manufacture, standard fiberglass materials produced by the continuous method can be widely used: flat and corrugated sheets, as well as various profile elements. Glued structures allow the height and pitch of the middle layer elements to be relatively widely varied, depending on the need. Their main disadvantage, however, is the greater number of technological operations compared to solid-molded panels, which makes their production more complex, as well as the connection of the skins with the ribs less reliable than in solid-molded panels.
Fully formed panels are obtained directly from the original components - glass fiber and a binder, from which a box-shaped element is formed by winding the fiber onto a rectangular mandrel (Fig. 1.16). Such elements, even before the binder hardens, are pressed into a panel by creating lateral and vertical pressure. The width of these panels is determined by the length of the box elements and, in relation to the industrial building module, is taken to be 3 m.
Rice. 1.16. Translucent, fully molded fiberglass panels
A - manufacturing diagram: 1 - winding fiberglass filler onto mandrels; 2 - lateral compression; 3-vertical pressure; 4-finished panel after removing the mandrels; b-general view panel fragment
The use of continuous rather than chopped fiberglass for solidly molded panels makes it possible to obtain a material in panels with increased values of elasticity modulus and strength. The most important advantage of solidly molded panels is also the single-stage process and increased reliability of connecting the thin ribs of the middle layer with the skins.
At present it is still difficult to give preference to one or the other technological scheme production of translucent fiberglass structures. This can be done only after their production has been established and data on the operation of various types of translucent structures have been obtained.
The middle layer of glued panels can be arranged in various ways. Panels with a wavy middle layer are relatively easy to manufacture and have good lighting properties. However, the height of such panels is limited maximum dimensions waves
(50-54mm), in connection with which A)250^250g250 such panels have ogre
Zero rigidity. More acceptable in this regard are panels with a ribbed middle layer.
When selecting the cross-sectional dimensions of translucent ribbed panels, a special place is occupied by the question of the width and height of the ribs and the frequency of their placement. The use of thin, low and sparsely spaced ribs provides greater light transmission of the panel (see below), but at the same time leads to a decrease in its load-bearing capacity and rigidity. When assigning the spacing of the ribs, one should also take into account the load-bearing capacity of the skin under conditions of its operation under local load and a span equal to the distance between the ribs.
The span of three-layer panels, due to their significantly greater rigidity than corrugated sheets, can be increased for roof slabs to 3 m, and for wall panels - up to 6 m.
Three-layer glued panels with a middle layer of wooden ribs are used, for example, for office premises of the Kiev branch of VNIINSM.
Of particular interest is the use of three-layer panels for the installation of skylights in the roof of industrial and public buildings. Development and research of translucent structures for industrial construction were carried out at TsNIIPromzdaniye together with TsNIISK. Based on comprehensive research
work row interesting solutions skylights made of fiberglass and plexiglass, as well as experimental objects were carried out.
Anti-aircraft lights made of fiberglass can be designed in the form of domes or panel construction (Fig. 1.17). In turn, the latter can be glued or solidly molded, flat or curved. Due to the reduced load-bearing capacity of fiberglass, the panels are supported along their long sides on adjacent blind panels, which must be reinforced for this purpose. It is also possible to install special support ribs.
Since the cross-section of a panel is, as a rule, determined by calculating its deflections, in some structures the possibility of reducing deflections is used by appropriately fastening the panel to supports. Depending on the design of such fastening and the rigidity of the panel itself, the deflection of the panel can be reduced both due to the development of the support moment and the appearance of “chain” forces that contribute to the development of additional tensile stresses in the panel. In the latter case, it is necessary to provide design measures that would exclude the possibility of the panel's supporting edges approaching each other (for example, by fastening the panel to a special frame or to adjacent rigid structures).
A significant reduction in deflections can also be achieved by giving the panel a spatial shape. A curved vaulted panel works better than a flat panel for static loads, and its contour facilitates better removal of dirt and water from outer surface. The design of this panel is similar to that adopted for the translucent covering of the swimming pool in the city of Pushkino (see below).
Rooflights in the form of domes, usually rectangular in shape, are arranged, as a rule, double, taking into account our relatively harsh climatic conditions. They can be installed separately
4 A. B. Gubenko
Domes or be interlocked on a covering slab. So far in the USSR, only domes made of organic glass have found practical use due to the lack of fiberglass of the required quality and size.
In the covering of the Moscow Palace of Pioneers (Fig. 1.18) above the lecture hall, the lecture hall is installed in increments of about 1.5 m 100 spherical domes with a diameter of 60 cm. These domes illuminate an area of about 300 m2. The design of the domes rises above the roof, which ensures better cleaning and discharge of rainwater.
In the same building, a different structure was used above the winter garden, which consists of triangular packages glued together from two flat sheets of organic glass laid on a spherical steel frame. The diameter of the dome formed by the spatial frame is about 3 m. Plexiglass bags were sealed in the frame with porous rubber and sealed with U 30 m mastic. Warm air, which accumulates in the under-dome space, prevents the formation of condensation on inner surface domes.
Observations of the plexiglass domes of the Moscow Palace of Pioneers showed that seamless translucent structures have undeniable advantages in front of the teams. This is explained by the fact that the operation spherical dome, consisting of triangular packages, is more difficult than seamless domes of small diameter. The flat surface of double-glazed windows, the frequent arrangement of frame elements and sealing mastic make it difficult for water to drain and dust to blow off, and in winter time contribute to the formation of snow drifts. These factors significantly reduce the light transmission of structures and lead to disruption of the seal between elements.
Lighting tests of these coatings gave good results. It was found that the illumination from natural light of the horizontal area at the floor level of the lecture hall is almost the same as with artificial lighting. The illumination is almost uniform (variation 2-2.5%). Determination of the influence of snow cover showed that with a thickness of 1-2 cm room illumination drops by 20%. At above-zero temperatures, fallen snow melts.
Anti-aircraft domes made of plexiglass have also found use in the construction of a number of industrial buildings: the Poltava Diamond Tools Plant (Fig. 1.19), the Smolensk Processing Plant, the laboratory building of the Noginsk Scientific Center of the USSR Academy of Sciences, etc. The designs of the domes in these objects are similar. Dimensions of domes along the length 1100 mm, width 650-800 mm. The domes are two-layer, the supporting glasses have inclined edges.
Rod and other load-bearing structures made of fiberglass are used relatively rarely, due to its insufficiently high mechanical properties (especially low rigidity). The scope of application of these structures is of a specific nature, associated mainly with special conditions operation, as, for example, when requiring increased corrosion resistance, radio transparency, high transportability, etc.
A relatively large effect is achieved by using fiberglass structures, exposed to various aggressive substances that quickly destroy ordinary materials. In 1960, only
in the USA, about $7.5 million was spent (the total cost of translucent fiberglass plastics produced in the USA in 1959 was approximately $40 million). Interest in corrosion-resistant fiberglass structures is explained, according to companies, primarily by their good economic performance indicators. Their weight
Rice. 1.19. Plexiglas domes on the roof of the Poltava Diamond Tools Plant
A - general view; b - design of the support unit: 1 - dome; 2 - condensate collection trough; 3 - frost-resistant sponge rubber;
4 - wooden frame;
5 - metal clamp; 6 - apron made of galvanized steel; 7 - waterproofing carpet; 8 - compacted slag wool; 9 - metal support cup; 10 -slab insulation; 11 - asphalt screed; 12 - granular filling
Slag
There are much fewer steel or wooden structures, they are much more durable than the latter, they are easy to erect, repair and clean, they can be made on the basis of self-extinguishing resins, and translucent containers do not require water meter glasses. Thus, a standard container for aggressive media with a height of 6 m and diameter 3 m weighs about 680 kg, while a similar steel container weighs about 4.5 T. Weight of exhaust pipe with diameter 3 m and height 14.3 mu intended for metallurgical production, is 77-Vio of the weight of a steel pipe with the same bearing capacity; although a fiberglass pipe was 1.5 times more expensive to manufacture, it is more economical than steel
noy, since, according to foreign companies, the service life of such structures made of steel is calculated in weeks, of stainless steel - in months, similar structures made of fiberglass are operated without damage for years. So, a pipe with a height of 60 mm and a diameter of 1.5 m has been in operation for seven years. Previously installed pipe made of stainless steel lasted only 8 months, and its manufacture and installation cost only half as much. Thus, the cost of a fiberglass pipe paid for itself within 16 months.
Fiberglass containers are also an example of durability in aggressive environments. Such a container with a diameter and height of 3 m, intended for various acids (including sulfuric), with a temperature of about 80 ° C, is operated without repair for 10 years, having served 6 times longer than the corresponding metal one; the repair costs alone for the latter over a five-year period are equal to the cost of a fiberglass container.
In England, Germany and the USA, containers in the form of warehouses and water tanks of considerable height are also widespread (Fig. 1.20).
Along with the indicated large-sized products, in a number of countries (USA, England), pipes, sections of air ducts and other similar elements intended for operation in aggressive environments are mass-produced from fiberglass.
