Complex repair of elevators

An elevator is a necessary and irreplaceable enterprise for food industry. It is a complex of buildings, intended for the protracted storage of large parties of grain and leading it to the standard state. Grain is kept in the silo corps provided with mechanisms for its loading and moving. 

Silo constructions are the basic component of an elevator. In the middle of the past century the classic monolithic silos made from concrete were widespread, and component constructions silo corps of type SCS at the end of the last century, with parts made from the reinforced concrete. High-strength concrete is needed for silos, because in a not enough durable concrete grain can collapse (be damaged with a concrete surface). In its turn, shell of grain is very hard too and can damage even metallic free-flow grain lines into holes. 

The protracted storage of grain-crops and quality processing of grain are possible only at stable terms. Reliability of elevator is extremely important therefore. It makes great requirements, both to building and assembling of elevator and to its exploitation. The rules of exploitation of elevator are written in its normative documentation. Alp-Prom Association gives to customers the rules of elevator exploitation at entering into contracts. They include the regular inspection of elevator buildings, diagnostics and evaluation of their technical state, and also skilled prophylactic and preventive-maintenance repair. 

 

Repair of the intersilo pouring 

The internal walls of silos are exposed to large loading. Tension from horizontal and compression from the vertical loading assists formation of cracks. Therefore these constructions need regular repair and strengthening. The Intersilo pourings are processed both-sides by cement-sandy solution. Thus from exteriority a smooth surface is formed, in order that grain flowed down easier and quicker, diminishing friction thereby.

For strengthening and reinforcement of silo corps on the whole a sleeving is also sometimes conducted, or a silos sleeving – it is setting monolithic reinforce-concrete holders in them.

Repair of the intersilo pouring the intersilo pouring after repair

Repair monolithic silos

Repair of combined silos

Cleaning of silo towers 

Mechanical cleaning of silo towers

Silo towers are designed for long-term storage and high-quality processing of large amounts of crops. This involves high demands on the reliability and serviceability of elevators. After all, even because of a minor damage that is not noticeable at the first glance, granary can leak due to atmospheric moistures, the humidity will make grain sticking to the silo towers walls, mold will form and insects infest under it - and the costly grain stocks lose in their quality and become worthless. To avoid this, regular checkups, preventive and preventative work are needed. One of the main and the most regular types of work is a mechanical cleaning of silo towers. It should be understood that the "weakest" points of silo towers, where grain adheres and accumulates, usually are the most difficult to approach. Besides, it is important to identify and treat injuries, because due to poor quality of surface repairs and more serious problems can appear in the future. That is why qualified professional is to be hired for maintenance work on elevators.

Despite the mentioned above, the mechanical cleaning of silo towers is often entrusted with elevator personnel. Such sort of cleaning has several objective disadvantages:
- adversely affects safety: elevator staff has no previous training and schooling, does not pass the medical examination for height work admission and work in exclusive spaces (and for such work a special certificate is required), doesn’t not have insurance and receipts);
- cleaning is not qualitative, as by means of using the standard Luther winches, that are commonly used, it is physically impossible to reach the opposite side of the silo tower and some tight places. This is true especially in silo towers with a circular cross section and a diameter of 6 m and in silo towers with a side hatch and in metal ones;
- usually just surface cleaning is handled, therefore only conical bottom gets cleaned;
- personnel can be totally unfit for the job because of the natural fear of heights.

It is also important to remember that when operating inside silo towers, it is forbidden to  shake thermal suspension and certainly to rely on it! Unfortunately, this is a common mistake for unskilled workers of silo towers. There are cases when the ragged thermal suspension inflicted serious injuries to workers.

"ALP-PROM" company employees are qualified and experienced personnel. Their obvious advantages are:
- training: qualification as well as medical, including all the necessary certificates;
- job technologies, including the complete and safe cleaning of walls and bottom of silo towers of dirt and residues left after construction (formwork, lifting devices, etc.);
- equipment, including not only the tools for the job, but also security tools: PPE, respiratory protection, and even autonomous unit for air supply required in the event of dusty conditions.

Reinforced concrete silos with a diameter of 6m BEFORE cleaning Reinforced concrete silos with a diameter of 6m AFTER cleaning
The silo of precast construction BEFORE cleaning The silo of precast construction AFTER cleaning
The area with sticking grain BEFORE cleaning The area with sticking grain AFTER cleaning
The silo of precast construction AFTER cleaning The storage basement AFTER cleaning the precast structures

Hydro cleaning 

Hydro cleaning of the internal parts of silo towers

Hydro cleaning of internal surfaces of the silo towers’ walls is applied when mechanical cleaning (with brushes and brooms) will not give a result desired. This happens because the walls of the silo towers may be polluted. Typically, water jetting is used when:
- adhesion of contaminants does not allow its deletion with hand tools;
- hardness of pollution does not allow its deletion with hand tools;
- mold pollution;
- pollution poisons the air in the silo tower and requires a high speed cleaning.

We use high (230 bar) and very high (500 bar) pressure for water jetting machines.

Advantages of hydro-cleaning of silo towers:
- provides top quality cleaning;
- does not damage the surface gloss of the building;
- strays slightly frozen sections of concrete and aggregate of seams;
- all the dirt particles are washed away with flood waters;
- is non-sparking in the duration of the process.

Difficulties for hydro cleaning of silo towers:
- the need of ensuring the water supply to the unit in the amount of pressure 0.9 m3/hr;
- the necessity of providing drainage to mud weights about 1.1 m3/hr;
- the need for personal protective equipment for the operator: wetsuits, masks, visor, helmet, gloves, shoes;
- high efficiency of the barrel gun and as a result, operator’s fatigue, especially when using ultra-high pressure apparatus;
- the need for continuous monitoring by 3 persons: for the state of the operator, for the water inlet and outlet;
- higher depreciation expense.

It is important to remember that performing works of hydro cleaning of silo towers by elevator staff on their own is:
- handled in violation of safety (no education and training, medical certificate with the admission to work at height-altitude works and works in exclusive spaces, insurance, receipts);
- of low quality as by using a winch, workers cannot reach the opposite wall of the silo tower, "hanging out" on one side (especially in silo towers with a circular cross-section with side hatch, and especially in metal silos);
- not performed because of the staff’s natural fear of heights.

BEFORE high-pressure water cleaning of the silo BEFORE high-pressure water cleaning of the silo
AFTER high-pressure water cleaning of the silo AFTER high-pressure water cleaning of the silo
High-pressure water cleaning of the silo High-pressure water cleaning of the silo High-pressure water cleaning of the silo
The water displacement device before high-pressure water cleaning of the silo

High-pressure water cleaning of silos from outside

Ultra-high pressure apparatus is successfully used for high-pressure water cleaning. Today it is indispensable for the preparation of steel and façade surfaces before painting and repairing of joints. It’s not a secret that good paint adhesion is impossible without proper surface cleaning. In fact, durability of the coating depends on adhesion. As a rule, high-pressure water cleaning is the only way to remove previous paint and sealant.

Dirtying of elevators is inevitable. Receiving and shipping of grain causes dust formation; therefore, the majority of constructions are always covered with a thin layer of dust. This dust helps to avoid adhesion of paintwork and sealing materials. Another common type of dirtying is moss and mildew growth, especially at the shadow side of grain storage section. That is why, silos require periodic cleaning.

The benefits of high-pressure water cleaning of the grain elevator’s walls with ultra-high pressure apparatus:
- It provides the high quality cleaning of concrete and metal surfaces;
- It does not damage gloss surface;
- It forces down weakly attached concrete and joint filler;
- It washes away all the dust particles by water flows;
- It prevents the spark formation;
- the speed is much higher in comparison with mechanical cleaning;
- It removes whitewash, sticking grain, mold, fungus growths, the remains of the previous paint with a weak adhesion and the upper layers of corrosion.

Moreover, the ultra-high pressure apparatus (500bar) gives the opportunity to remove complicated dirtying from the surface of the grain storage section:
- the previous sealant (butyl rubber, polyurethane, epoxy urethane);
- bitumen remaining after the roofing works;
- oil dirtying (runs of reduction gear);
- oxide of metal fastening elements and damaged armature;
- previous coat of color;
- plaster;
- corrosion of metal constructions (up to Sa 1 degree).

Some difficulties of high-pressure water cleaning:
- it requires the supply of water to the ultra-high pressure apparatus in the amount of 0.9 m3/hour;
- it requires an outfall with mud masses about 1.1 m3/hour
- it requires personal protective equipment for operators: suits, respirators, helmet, helmet, gloves, footwear;
- Fast physical weariness of the operator when using a high pressure apparatus due to its high recoil;
- It requires 2 people: to look after both the operator’s condition and water supply & drainage;
- high depreciation expenses;
- probability to wet the grain inside the grain storage section.

High-pressure water cleaning BEFORE and AFTER high-pressure water cleaning The area BEFORE high-pressure water cleaning
The area AFTER high-pressure water cleaning BEFORE and AFTER high-pressure water cleaning BEFORE and AFTER high-pressure water cleaning
Removal of the defective sealant and organosilicone paint with the use of ultra-high pressure apparatus (500bar) Preparation of metal facade surfaces for painting The butt-end of the silo BEFORE and AFTER high-pressure water cleaning
The butt-end of the silo BEFORE and AFTER high-pressure water cleaning

Pressurizing of guy-sutures 

Between wind and water of silos is joints and guy-sutures. In the process of grain supply they are exposed to difficult spatial ladening, so in course of time get shattered, violating not only durability of silos but also their moisture resistance. Small cracks in course of time appear, increase and begin to leak. The process of destruction is aggravated by weathering and changes of atmospheric temperature. 

When moisture penetrates into the elevator, the temperature can increase, which can cause even spontaneous combustion in a silo. And for the removal of enhanceable humidity drying of grain will be required, that needs big electric power consumption.

Even if an elevator is erected without defects related to the off-grade production of his making elements, their transporting or assembling, it however needs prophylaxis. Practice shows that it is the absence of preventive-maintenance repairs that mostly becomes a reason of large destructions even of monolithic silos and spoilage of the grain kept in them. 

For preventing the destruction of elevator and providing the proper terms of grain-crops storage a regular examination and corresponding repair of cracks, chips and falls, through holes, armature protection, verification of silos impermeability and other types of repair works are needed. To eliminate leakage in guy-sutures and joints or avoid it, pressurizing of guy-sutures, their sealing-off, putty, calking and hydro-isolation is conducted. The guy-sutures of elevator (internal and external) are exposed to the careful cleaning from dust, moisture and old cement layer, joints are made up again and processed by the special pressure-sealing materials. 

Outseams to repair Outseams after repair

 

Plastering of sutures

Pressurization of sutures

Replacement of windows 

Modern metal-plastic windows are an ideal variant for industrial buildings. Their advantages are obvious: impermeability, isolation from moisture, beauty and comfort. But it is important to remember that windows from metal-plastic, especially large ones, need ideally correct setting. For example, it is necessary to observe a gap between a window frame and opening in limits from 2 to 6 centimeters. This requirement is quite often violated during setting of large windows in frames that threatens not only with the disrepair of the window but also possible accidents.

In order to repose in the correct setting of metal-plastic windows in industrial building, this work is reasonable to entrust to the profile specialists. Alp-Prom Association has accumulated large experience in solving tasks on windows replacement of any sizes and configurations.

Over the past 30-35 years metal and wood fencing windows constructions got out of order on the old elevators. Therefore, entrepreneurs faced a serious and reasonable question: what to replace them with and how to maximize quality and cost?

Nowadays the most common option is plastic windows with double glazing system. Their price is quite democratic as well. We are talking about the windows made of polihlorfinil (PVC), reinforced with galvanized steel profiles. PVC – is a type of synthetic polymer, which for many years competed with other materials (wood, etc.) due to the pre-defined application properties.

The windows of industrial plants have to meet high requirements, due to the specifics of their work. Fire protection is incredibly important at grain enterprises. Therefore, the windows must meet the category of fire and explosion protection.

Metal windows are widely used as construction that can be easily discharged to reduce the force of the explosion. In the event of an explosion, they must be discharged (or collapsed), forming open apertures, thereby reducing the pressure of the explosion to the values ​​that provide the basic safety and protection for load-bearing structures of the building. In order to localize the explosion windows of easy dischargeable design are placed in the walls or inside surfaces of the building.  In the premises belonging to the category of fire and explosive ones, such windows are placed against outside walls or on the upper floors in multi-storey buildings.

Usually required area for easy discharged structures is at least 0.05 m2 per 1 m3 for premises of category A and not less than 0.03 m2 for premises of category B.

Metal windows have several advantages over wooden ones as they are:
- fire resistant as PVC is self-extinguishing material;
- moisture resistant (unlike wood, do not absorb moisture);
- easy to use (do not require periodic painting and lacquering);
- aesthetic and up-to-date;
- easy to clean (less than wooden ones, collect dirt, therefore wiping them is much easier);
- sealed (do not leak and are not blown through).
- ecofriendly (that is why can be widely used even in everyday life).

We handle turnkey construction projects for the windows replacement, unlike the majority of windows installers who do not restore assembly clearance and slopes, but just fill the gaps with foam.

From the variety of manufacturers and brands offered in the modern market these days we recommend Internova and WinTech windows.

Internova is a European profile system that is produced only in Slovakia at Nowacki chemical plant (www.nchz.sk) and nowhere else. It complies with all European quality standards (ISO 9001) and certifications. Internova is an environmentally friendly profile created using stabilizers Ca / Zn, instead of prohibited Pb / Cd.

Last modification for profiles of Internova is Frost Friendly is designed for countries with harsh climates. Even at -40 ˚ C, it has the same impact strength of kJ/m2 22-24 as well as normal profiles have at 0 ˚ C. The unique profile additives are used to prevent fading and UV degradation of PVC.

The combination of smooth contour lines of Soft Line, reveals and joint, location of fillet  in the same platitude with the frame (prevents dust and dirt from getting into the joints), in combination with the gray seal and a unique gloss gives the window a beautiful and elegant look.

WinTech are profile of PVC window systems that established themselves as reliable materials for affordable prices. Designs from WinTech withstand high static and wind burdens, therefore, allow working in a wide range of products dimensions, as well as according to the desires of the customer, not driving it within the constraints of market standards. Like in the Internova system a Ca/Zn stabilizer is used that meets European quality standards. WinTech system is very close to the analog of the European Union in its capabilities, thermal insulation and technical solutions.

Nowadays we believe that PVC windows are optimal for industrial buildings


Replacement of windows (view from outside)
Replacement of windows (view from inside)
Windows of the bin top floor before replacement Windows of the bin top floor before replacement Window replacement. The factory shop
Before window replacement at the feed mill After window replacement at the feed mill Before window replacement at the feed mill
Before window replacement at the feed mill    
After the internal installation of windows After the replacement of windows and doors; the slops has been restored from the inside Windows after installation and hermetic encapsulation from the outside

 

Painting of elevator buildings 

Painting of elevator buildings

Moisture harms not only grain-crops but also concrete. It is atmospheric moisture that is a principal reason of elevators destruction. The surface of concrete is porous and apt to the micro cracking. Getting into them, moisture strengthens destructions, especially as a result of carbonating and seasonal freezing and thawing. Thus, even insignificant micro cracks, appeared from dampness, can cause serious scaling up destructions.

Except physical influence through washing out of pores, a rain-water harms concrete chemically. In the atmosphere there are gaseous productive emissions that get into the rain-water and convert it into acid solution, destroying concrete.

Painting of elevators will help protect concrete from harmful influence of moisture. For the best effect it is needed to use the special crack-resistant paint, and also to conduct general hydro-isolation and hydro-phobization of the building.

During hydrophobization concrete is saturated with a water-repellent agent, strengthening the structure of building material. Hydrophobization promotes resistance of the building to corrosion and frost-resistance.

Painting of grain storage section with the crack resistant coating Grain storage sections before repairing and painting Grain storage sections after repairing and painting
Grain storage sections during hermetic encapsulation Grain storage sections after repairing and painting The headhouse after repairing and painting (2006)
The headhouse after repairing and painting 6 years later (2012) Grain storage sections before repairing and painting Grain storage sections after repairing and painting
The headhouse after repairing and before painting The headhouse after repairing and painting The elevator tower BEFOR cleaning
The elevator tower AFTER painting Elevator building before painting Elevator building after painting

Painting of elevator buildings

Painting of elevator buildings helps in the struggle against corrosion of metals. Lacquers and paint, materials that we use give the steady sheeting, and also improve original appearance of buildings.

The efficiency of painting of productive metal constructions in a large measure depends on the quality of their pre-cleaning. Well the method of the hydrodynamic cleaning showed itself through a high-pressure apparatus "KARCHER". After cleaning metal constructions are grounded and painted by enamel.

Before painting After painting

Whitewashing of technical floors and storages

The most widespread coverage of elevator walls is whitewashing. For industrial building this means is the most widespread: simple in application, inexpensive and, at the same time, effective. For the concrete surfaces of elevators, where practicality, rather than just aesthetic dignities, goes out into the first place, mixtures are used on the basis of lime or on liquid glass. Such silicate whitewashing perfectly lies down on ( covers) cement materials. At will of customer - it is possible to add disinfection substances in whitewashing solution.

Whitewashing of technical floor

Painting of norias and dryers

The special care is required for the mechanical devices of elevators - norias and dryers. Grain directly adjoins with their surface, the quality of coverage is very important therefore. Often for painting of these mechanisms the dough-like metal-backer compositions known as "Smolt" is used. Drying oil or varnish, aluminum powders, solvent are included in its composition. The main advantage of this means is low cost. However the cheapness of "Smolt" quite often affects on quality: the producers of solutions use unstandardized raw material that cannot give the even, steady, reliable layer of coverage. If to take compositions of reliable producer, the price becomes higher. In addition, for the homogeneous laying of "Smolt" the house-painters of high qualification are needed as the work requires experience and mastery.

Nowadays as an alternative to "Smolt", there appeared stock-produced compositions among which we can recommend agents for sopheisation. It is the zinc compositions on the basis of organic resins, intended for an underseal. Sopheisation not only gives an external corrosion protection of long duration but also removes all tracks of moisture from pores and microcracks, removing thus internal, so-called, subpellicle corrosion.

Dryer to painting Dryer after painting

 

Zinc-coated surfaces restoration 

Dozens of new grain elevators consisting of zinc-coated silos and galvanized metal constructions have been built in Ukraine over the last few years. However, in most cases the durability of zinc metal protection is significantly less than expected. Some constructions require restoration of zinc-coated surfaces in 2-3 years after the assembling, or even at the stage of installation.


1. Sofeisation

Sofeisation is the process of deposition of anti-corrosion coatings on the basis of organic resins. The durable coating (primer) is applied to the adjacent layers of rust and scale. It is more fluid than water; thus, it penetrates the pores of the oxide up to the metal unaffected by corrosion. This way, it removes the cause of internal corrosion: oxygen and moisture. Apart from that, sofeisation thoroughly cleans the metal surface, making it firm & durable and eliminates the possibility of underfilm corrosion after painting.

 

 

Polymerization with the use of sofeisation will reliably protect the steel, iron, aluminum and stainless steel constructions and components from corrosion. Moreover, it prolongs the durability of permanent coatings.


Material for sofeisation – agent R-101

This is a unique protective anti-rust agent on the basis of epoxy-phenolic-formaldehyde resin. The properties:
- high hydrophobicity, fluidity;
- high penetrating ability;
- nonporosity of duplex coating 99,99 %;
- underfilm corrosion prevention;
- resistance to atmospheric influence.

R-101 is suitable for surfaces made of ferrous and non-ferrous metals, wood and concrete. It can be used both inside and outside. Furthermore, this agent can be used as a decorative coating without painting.

Technical qualities:
- high corrosion resistance at temperatures -60 – +105С;
- heat resistance of pigmented aluminum paste – up to 300C;
- consumption: 15-18 m2/l;
- complete drying time: 2 hours.


2. Cold zinc plating

Today many corrosion-resistant zinc-containing coatings are presented by foreign manufacturers. In recent years, our manufacturers offer analogues far reaching products as well.  Each material has its benefits depending on the field of application. It is important to distinguish methods of cold galvanizing from corrosion-resistant paint coating.

Lots of manufacturers of zinc-containing coating tend to determine the application methods as «cold zinc plating» or «galvanization». However, they often forget about the important requirements for this kind of coatings according to the international standards. They are:
- the maximum size of the faction of zinc particles weighted in the polymeric binder;
- their percentage in ready for application mix and in dry polymerised coating;
- electroconductivity of hardened coating, i.e. its specific electric resistance;

Apart from that, keep in mind that the cost of materials mentioned in the overall estimate of expenditures is only about 30%. The remaining 70% – is the cost of works related to preparation of materials and surface, its application, etc. The key factors are – the permissible degree of a metal surface preparation and the number of applied coats in order to provide protection of the finished unit and prevent it from corrosion for a guaranteed period. Apart from that, the preparation of the material before the applying and its «survivability» after the preparation are very important. It should be noted that two-component epoxy or polyurethane materials are very toxic and difficult in preparation before the application. They have a short-term period of «survivability» (2-3 hours), whereas one-component material under condition of the container tightness can be reanimated at any time with the use of standard solvents.

The methods of corrosion protection of metals can be divided into:
- Active (galvanic). Coating material (zinc) and protected metal form a galvanic pair – where the protected metal is the cathode, whereas the attached coating is anode;
- Passive. Film (barrier) protective coating is formed and held on the surface of the protected metal due to adhesion. This coating isolates the metal from the adverse effects of aggressive environment.

Passive protection is provided by film-forming lacquer coating. The content of zinc is caused by the necessity of «packing» (seal) of the polymer binder porous structure due to the oxidation of zinc grains up to carbonates and their «swelling».

Peculiarities of cold zinc-coating:

1. Fraction of zinc particles is 3-5 micron.  They have the form of thin flakes in thickness from several tens to several hundreds of atomic layers. This size and shape of zinc particles provide good electrical contact between them and the rough surface of the protected metal. The coating acquires a positive charge due to the ejection («offering») of electrons into the iron; thus, it becomes electroconductive and forms a galvanic pair with iron.

 

← To the left — particles of zinc in zinc-containing paints.

 

 

 

 

To the right — particles of zinc in Zinga. →

 

2. The zinc content in the paste is not less than 81%, whereas in the dry layer – not less than 96%. The part of polymer and solvent are volatile substances; thus, they evaporate at drying.

3. The single component formulation provides long-term storage under condition of hermetic container and quality solvent.

4. In accordance with the ISO 12944 and ISO 9223, the reduction of zinc coating thickness in category C3 should not exceed 2.1 mm per year. Thus, the thickness of coating in 40-60 microns provides protection against corrosion for 15-20 years.

5. Surface preparation Sa 2.5 is required before coating deposition, instead of Sa 3 (as for zinc-containing paints). The sufficient roughness under the formulation for the zinc coating Zinga is 15-20 microns, whereas for equal degree of adhesion of the zinc-containing coat the roughness should be about 35-45 microns.

6. All two-component materials have limitation of temperature and drying time. They require applying to absolutely drysurface without any signs of rust. Zinga can be applied to the wet surface at environment temperature -15 C – +45 C. The layer of rust up to 70 microns is allowed so as it does not prevent the formation of a galvanic pair on the surface.

The material for the cold zinc-coating: Zinga

Zinga - is one-component ready to use formulation. 96% of atomized zinc with 99,995% of purity and particle size – 3-5 microns are included in this formation.

The uniqueness of this product is in the ability to give the barrier (similar to ordinary paints) and cathodic protection of steel (similar to the galvanic coatings). Apart from that, each particle of zinc has additional protection due to the neutral resins. The breakdown rate of Zinga is about three times slower in comparison with other materials. Before applying Zinga, the earlier zinced surface should be cleaned from dirt & oils and flushed with running water under the pressure of 100 – 200 atmospheres. Then, Zinga is applied as a usual paint with the use of brush, roller and spray gun or by dipping.

Zinga can re-dissolve; thus, through the time, you can apply a new layer, which will merge with the old one and restore cathodic protection of steel. You can apply the formulation in any weather, even if the surface is wet and a little rusty.

Mechanical characteristics:
- resistance to temperature from -50 C to +150 C and acid-alkaline range of 5-10 Ph.;
- color: light-gray, mat;
- drying time up to degree 3: 15-30 minutes at the temperature of 18-20 degrees C;
- adhesion: 1 degree;
- impact strength: 50 cm;
- pendulum hardness: 0,6;
- elasticity in bending: 1 mm.

Zinc-coating allows contact with water and has a zero degree of flame spread over the surface (class A1).

BEFORE using the corrosion preventing agent AFTER using the corrosion preventing agent
BEFORE using the corrosion preventing agent AFTER using the corrosion preventing agent
BEFORE using the corrosion preventing agent AFTER using the corrosion preventing agent
BEFORE using the corrosion preventing agent AFTER using the corrosion preventing agent
BEFORE using the corrosion preventing agent AFTER using the corrosion preventing agent
Surface preparation before using the corrosion preventing agent

Repair of soft and hard roof 

Industrial mountaineering, and more precisely its methods, is widely used for repair of soft and hard roof. It allows to simplify a working process substantially and reduce expenses on it, because setting of additional devices for industrial alpinists’ work is not required. 

A coverage of a building, intended for taking of rain and melted water, protecting from a sun and frost is called a roof. A roof executes a major task - it protects building from atmospheric fallouts, the main enemies of buildings. That is why it is important to keep a roof in good condition state: its any damage will entail further destruction of the construction. The missed out necessity to get a roof permanently repaired can become a reason for the necessity to perform a thorough repair of all the building.

As a roof is constantly exposed to direct influence of environment, it must be waterproof, moisture-resistant and frost-hardy, not liable to solar radiation and aggressive chemical substances soaring in the atmosphere. A roof material must not be warped, melt and ravel. In this connection, setting of roof is a responsible and labor intensive process, and its maintenance must be fulfilled carefully. A roof must be heat-insulated if necessary, and on the inside protected from a runback. General overhaul of a roof includes repair of gullies and storm collectors.

A roof consists of a bearing layer and a coverage. A bearing layer is laid on the load carrying structure of the roof that can be sloping or horizontal relative to the earth. The planes of a roof are called skates, places of their joints - ribs or skates, if they are located horizontally. Exactly this zone needs the most intent attention, the least cracks or damages here will entail deformation and destruction of all the roof. 

Another important element of a roof is cornices protecting the overhead part of walls of a building from fallouts. 

Modern roofing coverage consists of a few layers with different functions and properties : bearing, isolation, warming etc. It is important to choose their combination correctly. New technologies are widely used  at repair of old roofages, that substantially promotes its quality and prolongs the term of exploitation of the building on the whole.   

Depending on coverage roofs are divided into hard and soft. The choice of one or another  coverage depends mainly on the angle of slope. At a slope more than 15° assembling of hard roof is executed, at a less slope - soft. It is connected to the fact that at small inclination of skate the joints of hard roof are not enough impermeable. It is important to take into account this factor at assembling and repair of a roof, especially when setting a combined coverage. 

At present there is a great choice of materials for roofing coverages, both hard and soft roof: sheet steel and copper, ruberoid, prof.covering, metallic tiling, bituminous folias and tile, ceramic tile, tree, natural stone, asphaltic paper, tarred roofing paper, keratoplasty. The choice of material depends on architectural features and functional setting of buildings.

For coverage of industrial building a mainly soft roof is used, that it contingent by its practicality. Abat-jours and cornices of building can have hard coverage, depending on their configuration. 

 

Repair of subsilo abat-jours  

An abat-jour to repair An abat-jour after a plaster
An abat-jour after repair

 

Repair of peaks of ground technical floor 

An abat-jour to repair
Fixing of timbering An abat-jour repair
An abat-jour after repair

Repair of a soft roof  

A roof to repare
A roof is dismantling of mat
A roof – placing of curbs A roof - setting of brackets
A roof – mounting of timbering
A roof – timbering A roof – abat-jours A roof – a view from the ground
Roof - after setting of a squared beam A roof - piling a strainer
A roof – piling a strainer A roof – after piling a strainer
A roof – application of the 1 layer
A roof – placement of the 2 layer
A roof - repair process
Roof after repair
The soft roofing has been carefully completed under the aerial feeder equipment The soft roofing of three grain storage sections after repairing

 

Repair of abat-jour of the overhead technical floor  

An abat-jour before the repair
An abat-jour - application of timbering
An abat-jour - application of a solution An abat-jour - application of zinc coating
An abat-jour – bottom layer application An abat-jour - application of topping

Repair of transitional galleries 

Transitional galleries are a part of a building, requiring special attention to its state from considerations of safety. Nowadays it is recommended to substitute out-of-date slate of old elevators by the zincked and/or painted profiled sheet. We also offer slushing treatment of gallery framework, and at a necessity smoothing or replacement of its bearing elements.

Repair of galleries

 

Repair and renewal of reinforce-concrete columns 

A widespread defect of elevators, that can entail serious destructions, is cracks of columns or their overhead parts - caps. Especially often they arise up in subsilo apartments. Depending on the character of cracks and degree of destructions different repair works are conducted. We offer repair or strengthening of columns on a model project or on a worked out one for a special case. As a rule, cracks are processed and staved by metal bondage - by a corner and a channel bar, depending on the configuration of the defect place. More sound treatment is possible by means of building chemical facilities or composite materials. A colon can be fixed by the additional layer of repair mixture, for example, self-packing mixture SIKA.

Concrete columns are the essential load carrying part of grain elevators. However, heavy pressure, excessive load and internal pressure which exceeds the ultimate strength may cause cracks at the capitals of columns. This leads to the destruction of the whole structure.

If you notice cracks, cosmetic repair won't help you solve the problem. Firstly, the thorough technical analysis of cracks is highly important. You need to determine if they represent a danger to the structure. Such criteria as the target crack width, thickness and strength of the concrete layer at the place of cracks formation, short-term and long-term loads, temperature differential and dynamic force should be taken into account.

The following construction elements require special attention:
- construction joints;
- monolithic building elements;
- joints between light and heavy elements;
- transition angles and cracks at the cross-section;
- areas which can be under the effect of impact loads.

In case of cracks formation, packing of voids and adhesive bonding is defined as injection. This process is used to increase the carrying capacity of reinforced concrete structures. The epoxy two-component mixture is used for increasing the reinforced concrete elements, so as the strength and adhesion of this mixture is higher than concrete strength. Apart from that, cracked reinforced concrete bridges, chimneys, columns, walls, beams of industrial buildings can be also repaired with the help of this technology.

Special methods of thorough examination should be used before the operational period of damaged structures would be extended. The method of crack filling will depend on the construction material and character of damage.

Changing the width (Δw) is a key factor when choosing the suitable injection material for the fissure occupation. The formation of cracks can be caused by short term reasons (transport movement), everyday reasons (sun exposure) and lasting impact (seasonal changes). Moreover, not only can the formation of cracks be local, but also in conjunction with the shrinkage or other conditions.

Remember that injection materials which form a stiff system during the polymerization (e. g. epoxy, rigid polyurethanes) should only be used if the reasons of crack formation were defined and eliminated. Otherwise, new cracks may appear under the effect of slip.

The crack. Statement of problem Injection. The use of the packer Seminar SIKA on the Injection Methods
Seminar SIKA on the Injection Methods   Our specialist are performing the injection procedure

Reinforced concrete restoration 

The supporting structure and the framework of elevators are the foundation of integrity and security, which the strength and reliability of the entire structure depends on. Many elevators (especially large ones), which are operated these days, have a frame made of reinforced concrete. The known advantages of concrete are such as durability, strength, fire safety, etc. However, concrete is quite a brittle material and always has some cracks. Not all cracks are dangerous, but under the influence of the environment, they can cause serious defects.

 

A few examples:
1. The atmospheric moisture can get into cracks that exacerbate destruction during seasonal freezing and thawing.  In order to prevent the development of cracks, it is important to provide the ferroconcrete with the water flow. For example, you can extend and repair the crack, and after that cover the crack with some crack resistance paints.
2. Reinforced concrete is based on an armouring, which may be harmed by corrosion due to precipitation. Because of the metal corrosion, the armouring increases in its volume and located within the concrete destroys it from the inside. That is why spoiled fitting is to be replaced if necessary and its defective parts are to be repaired, the surface is to be painted.
3. The surface of the concrete is exposed to weathering. This process can be prevented by covering the concrete structure with crack resistance paints.
However, not only the environment destroys the concrete. The cause of its damage is often the improper use of the object.
For example:
- failure of silo’s circuit loading;
- lack of preventive maintenance;
- lack of blind area and drainage system in the enterprise, which can lead to subsidence of the building;
- the absence or failure of thermometry;
- a design flaw;
- inconsistent with the project organization of reconstruction and modernization. For example, changing the schema of shipment of grain out of the bin without a corresponding increase leads to the destruction of the walls of the silo tower and loosening fasteners.

 

Special attention is to be paid to the power cracks. It is important to distinguish them from the other (corrosive and plaster layer) cracks. Representatives of specialized institutions can only do this procedure. It is necessary not only to repair the power crack correctly, but also to establish the reason for their appearance.

Cracks in the column capitals of the floor under the silo towers are especially dangerous. Experts can distinguish and remove the reason of their formation by investigating the nature of the position and angles of the cracks. However, the enterprises’ employees often make superficial repairs - stick cracks and bleach them - and therefore exploring the building becomes very difficult.

Special project organization chooses the recovery circuit for concrete in each particular case, depending on several factors:
- the aggressiveness of the environment (climate, location of the building in relation to topography, the presence or absence of chemical production and chemical waste products);
- period of the year for the work to be done;
- a desirable exploit guarantee period;
- required characteristics of the concrete (strength, workability, curing speed, etc.).

Concrete restoration on the sea coast in accordance with Reomat technology Concrete restoration on the sea coast in accordance with Reomat technology The clearing of concrete according to the requirements of SIKA
The cleaning and partial replacement of armature according to the requirements of SIKA The cleaning and partial replacement of armature according to the requirements of SIKA Applying the adhesive layer to the repaired surface
The concrete geometry restoration with the use of small grained filler The concrete geometry restoration with the use of small grained filler The surface coating
The surface coating The bin bottom of the round silo BEFORE recovery The bin bottom of the round silo AFTER recovery
The restoration of backings in the silos The restoration of backings in the silos The covering restoration after the replacement of norias
The covering restoration after the replacement of norias Typical defects of reinforced concrete walls of grain elevators

The metal construction painting 

The main problem for metal is corrosion. The most common type of corrosion is atmospheric one. It appears because the majority of vehicles, machinery, steel structures and facilities are operated in the open air. Some moisture condenses on the metal surface that is an electrolyte containing various chemicals.

Coating materials that do not absorb moisture and protect the metal surface are used for the prevention and removal of corrosion. Paint and polish systems not only protect the metal mechanisms and structures from harmful environmental effects, but also aesthetically enhance their appearance.

The most common scheme used in manufacturing plants for the metal protection is priming and painting with enamel. The type of the enamel and the number of applied layers depend on the aggressiveness of the environment.

It is important to prepare the steel structure for painting in a proper way. Salt, oil and grease, dust, dirt, old coatings and mold build-up are to be removed from the surface.

For high quality and reliable metal cleaning before painting, which would be the key to its strength, we recommend applying a water jetting method, using a high pressure KARCHER instrument. The device provides a powerful jet, which deeply penetrates into the surface and erases any contamination, including previous coverage and scale.

Modern paint materials permanently extend the life of buildings and structures. It is just necessary to choose the right type of coverage and in the case of using several paints – to check their compatibility.

The blind area construction 

In order to protect elevators and grain buildings from the rain, an effective drainage system is necessary. It includes drains, blind areas and gulleys. It is recommended to inspect them annually during spring technical inspections.

A very important part of the drainage system is a blind area as it prevents the ingress of rainwater into the room and the silo towers. In order to prevent water from accumulating around the building, the area around it should be sloped from the walls. For diverting water around the entire perimeter of the building the blind area must be designed with the width of at least 1 m (depending on the type of soil, in the case of the loess soils - 2 m) and gutters for delivering water from the stores.

Blind area must be located in an obtuse angle to the building, and the gap between this area and the walls should be sealed with hot bitumen, cement or rosin. A blind area made of ​​asphalt is recommended around silo towers buildings. This material is durable and reliable, but is not used around residential buildings, as it is not environmentally friendly. It is necessary to prepare a trench around the building for the developments of the blind area. It is to be filled with compacted gravel layer of 15 cm and to be topped by a layer of asphalt 3-5 cm thick.

Blind areas not only protect the building from rain, but also serve or a decorative function, whereas it forms a path around the building. Developing of functional and aesthetic blind area is a complicated process that requires a high level of professionalism of performers and special equipments.

Waterproofing and sealing of silo buried tanks 

Our company has more than 10 years of experience in Ukrainian elevator repair service. It allows us to state with confidence that most of grain elevators require repair, waterproofing and sealing of buried tanks. First of all, it relates to bottom conveyors and conveyor galleries, elevator towers and grain tanks (auto and railway unloading). Moreover, this concerns both the elevators which were built in the Soviet Union and modern complexes.

Condition before waterproofing

The technical condition of the reinforced concrete grain elevator depends on the influence of mechanical forces and external factors.

Damages caused by external factors reduce strength and durability of reinforced concrete elements of grain elevators. If damaged areas would be left unrepaired and unprotected, they could lead to the destruction of individual structural parts of the elevator as well as the whole construction.

There are many reasons why atmospheric, technical or ground water penetrates inside the underground premises. It can be caused by features of soil (unfortunately, farmers often save on the geological studies of the soil where construction of the elevator is planned), errors in design, poor quality and care of concrete, procedural violations during construction works, especially when waterproofing and sealing.

As practice shows, lack of attention paid to sealing of expansion joints of bottom conveyor galleries. However, a significant amount of water penetrates into the gallery through these joints. Apart from that, keep in mind that expansion joints of bottom conveyor galleries help compensate pressure in case of uneven load.  High vibration endurance and large deformations (25-50%) are typical for these joints.

Expansion joints before waterproofing

Therefore, the sealing of expansion joints of underground silo galleries requires an integrated approach: careful selection of technologies, materials and qualified performance of works. Each expansion joint is unique and requires a responsible approach. Therefore, we use various technologies of seal, optimally corresponding with working conditions of the particular unit. Standard solutions and universal materials cannot be used in this case.

The process of sealing the joints should be performed outside as well as inside. However, the most time consuming process is joint preparation before sealing: concave joint, the dismantling of the boards and/or foam plastic at the depth of application of sealing material, weld cleaning; restoration of destroyed edges and stop of enforced flow, if necessary.

The results of examination and performance of work at elevators show that the most vulnerable places of underground elevator towers and bunkers of self-dumping are joints "floor-wall" and working joints of concrete. Apart from that, the capillary suction should be taken into account (i.e., penetration and movement of moisture in concrete, due to porous structure of concrete).

Concrete always has a lot of capillaries, voids and cracks, even if it is made «correctly». They cause water penetration which in conjunction with aggressive fluids destroys concrete.

It’s important to fix leaks; otherwise, water will penetrate into the concrete.  In case of temperature difference or repeated cycles of freezing and thawing the water inside the concrete will expand micro-cracks and destroy the construction. These destroying processes are especially noticeable in underground and semi-underground premises of elevators. Corrosion of concrete and armature is visible to the naked eye.

Condition before waterproofing Expansion joints before waterproofing

Our company offers a wide range of modern technologies and materials which are successfully used for restoration, structural repair and waterproofing of underground concrete structures from the inside.

A few words about silos foundations.

At the stage of project development all specifics of the place should be taken into account. It’s important to consider the quantity and frequency of moisture that will affect the foundation.

As previously mentioned, concrete can pass moisture. Reinforcement within the concrete tends to corrode, that leads to crack formation.

The foundation will be reliable only if the type of silo bedplate waterproofing is determined at the stage of project development before the installation of foundation. It is especially important for the areas where the level of ground waters is high.

Although lots of builders feel confident in installation, the waterproofing of silo foundation should be performed by professionals of particular specialization. Waterproofing of silo foundation have to be done correctly and reliably at once; otherwise, opening of waterproofing for repair will cost a lot of money. And certainly, this is not a place for experiments.

Despite the fact that many specialists can build perfectly, they do not know how to perform a comprehensive, durable and reliable waterproofing of buildings which will serve for dozens of years.

Another typical mistake is when a customer buys expensive certified materials, but the work has been performed by a team without experience and license. It leads to the violation of technology.

The consequences are easily predictable – the structure loses its strength and eventually becomes destroyed.

Truly reliable and cost-effective solutions require the proper analysis of situation, professional approach and right materials. Our company uses technologies that guarantee a reliable waterproofing and protection of silos concrete foundations from the water and weather impact.

  Condition after waterproofing

Amateurs’ incidents 

In recent years, the leaders of grain enterprises are increasingly faced with amateurs repair work at height. They are characterized by decisiveness in the negotiations, the promises of generosity and frequent changes in the organization names and phone numbers.

The number of these "professionals" is growing, and we decided to collect the works of amateurs found as a warning, because for all the services the customer pays his own money.

2 years after repair The sealant has been applied to the unprepared surface The installed clearance shouldn’t exceed 6cm
The sealant has been applied to the unprepared surface The installed clearance shouldn’t exceed 6cm Roofing sealant on the wall of the grain storage section
Roofing sealant on the wall of the grain storage section Cement-sand mixture is used instead of resilient sealant Sealing with the bubbles and emptiness
The sealant was applied at freezing temperature The sealant is flaking along with the rolling grout High-pressure water cleaning of the components with numerous interstices
Sealing of joints with assembly foam. Foam is not a sealant; however, it prevents the structure from the fast flowing water. The replacement of equipment Shaking out of bins
The window is not waterproof. Ice can damage the glass from the inside Incorrect direction of self-tapping screws, differing length of steel sheeting and lack of cover strip The incompatibility of paint and sealant
The incompatible sealant was applied before the removal of the previous bituminous sealant The nonfunctional and unaesthetic outflow In-swinging window
The lack of sealant on the cracks. Cracks, delamination and leakages are inevitable Cleaning was not carried out before painting The putty without sealant 1 year latter
The headhouse. 2 years after repair Joints are filled with sand grout