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Solution of Foundation, concrete, earthquake related queries are published here.
Frp Tanks: Built To Last
FRP Storage Tanks:
FRP Storage Tanks are built to last
FRP storage tanks offer reliability, corrosion resistance and advanced engineering designs for both aboveground and belowground storage tanks.
UL Listed single-wall and double-wall construction are available for many industries. Double-wall tanks can accommodate a wide array of high-tech electronic leak monitoring and stored product control equipment.
FRP Storage Tanks are built to last
FRP storage tanks offer reliability, corrosion resistance and advanced engineering designs for both aboveground and belowground storage tanks.
UL Listed single-wall and double-wall construction are available for many industries. Double-wall tanks can accommodate a wide array of high-tech electronic leak monitoring and stored product control equipment.
FRP aboveground tanks are ideal for:
- Acids
- Caustics
- Solvents and non-flammable corrosive fluids in petroleum production, chemical, pulp and paper, and other industrial applications
FRP Shop Fabricated Aboveground Tank sizes range from 40 to 60,000 gallons in capacity. Field erected sizes are larger.
It is
- Environmentally Safe
- Will Never Rust
- Durable Long Life
FRP Underground Tanks are ideal for:
- Gasoline
- Jet Fuel
- AV-Gas
- Motor Oil
- Kerosene
- Diesel Fuel
- Alcohol-Gasoline Blend Motor Fuels
- Ethanol-Blend Motor Fuels
- Methanol Blends
- Oxygenated Motor Fuels
- Water & Septic
- Any Gasoline/Ethanol Blend, including 100% Ethanol, Methanol or M85
FRP Underground Tank sizes range from 285 to 50,000 gallons in capacity, and from 4 to 12 feet in diameter and 6-1/2 to 73 feet in length.
Why use FRP?
The MAIN characteristics of thermo sets (literally 'setting under heat') is that they require
curing, when they undergo a molecular cross-linking process which is irreversible and renders them infusible. They thus offer high thermal stability, plus good rigidity and hardness and resistance to creep. It also means that, once cured, the resin and its laminate cannot be reprocessed, except by methods of chemical break-down, which are currently under active development. For practical purposes, therefore, cured thermosetting resins can be recycled most effectively if ground to fine particles, when they can be incorporated into new laminates, as cost-effective fillers.
Thermosetting resins have little use as pure resin, but require addition of other chemicals to render them process able. For reinforced plastics, the compounds usually comprise a resin system (with curing agents, hardeners, inhibitors, plasticizers) and fillers and or reinforcement. The resin system provides the 'binder', to a large extent dictating the cost, dimensional stability, heat, chemical resistance and basic flammability. The reinforcement can influence these (particularly heat-and dimensional-stability), but the man effect is on tensile strength and toughness. High-performance fibres, of course, have a fundamental influence on cost.
Special fillers and additives can influence mechanical properties, especially for improvement in dimensional stability, but they are mainly used to confer specific properties, such as flame retardancy, UV stability or electrical conductivity.
Thermosetting resins are normally used in the liquid state and solidify and harden on curing. With some resins it is possible to part-cure and then hold the resin in what is termed the B-stage, for the cure to be completed at later time.
FRP Properties
Epoxy
Excellent composite properties, very good chemical resistance, good thermal properties, and very good electrical properties, and low shrinkage on curing and can be B-staged.
Phenolic
Very good thermal properties, good fire resistance (self-extinguishing), B-stage possible, good electrical properties.
Polyester
Wide choice of resins, easy to use, cure at room temperature and elevated temperature, very good composite properties, good chemical resistance, and good electrical properties.
Polymide and polyamide-imide
Excellent thermal properties, good composite properties, good electrical properties, and good fire properties.
Polyurethane
Good composite properties, very good chemical resistance, very high toughness (impact) and good abrasion resistance.
Silicone
Very good thermal properties, excellent chemical resistance, very good electrical properties, resistant to hydrolysis, oxidation and, good fire properties (self-extinguishing)-Non-toxic.
Vinylester
Good fatigue resistance, excellent composite properties, very good chemical resistance, and good toughness
Polypropylene Fibers in Cement Mixes:tips for Right Use
The following info pertains to usual monofilament or fibrillated polypropylene fibers (not the structural ones).
Use polypropylene fibers….
1) For the reduction of plastic shrinkage cracks. This phenomenon evolves mainly during the first 6 hours after concrete or mortar casting.
2) For the reduction of plastic settlement cracks (evolving mainly the first 3 hours).
3) As a secondary, triaxial reinforcement to intercept early crack formation.
4) For the production of thin section building elements.
5) For better impact resistance and shattering behavior.
6) To increase abrasion resistance in concrete floors. Polypropylene fibers reduce bleeding and surface cracking. Much dusting is produced by crack edges’ fracturing.
7) In combination with air entraining agents to improve concrete’s behavior to freeze-thaw cycles. The synergistic effect of these materials is powerful!!
8) To give extra protection against carbonation and reinforcement corrosion.
9) For longer life and higher concrete durability.
10) To reduce explosive spalling in case of fire e.g. in tunnels.
11) To reduce rebound of sprayed concrete (increases cohesiveness).
12) To reduce cracking and water permeability in screeds and mortars.
Don't use polypropylene fibers...
(1) for less water permeable concrete. PP fibers could only marginally contribute to this. To reduce concrete water permeability it's much easier to use:
- a PCE superplasticizer to attain a water-to-cement ratio not more than 0,45
- some pore blockers as for example silica fume
- integral waterproofers based on esters of stearates. These products line concrete pores with hydrophobic substances and reduce intermolecular adhesion forces between pore walls and water.
-integral waterproofers based on proprietary,penetrating salts:crystallization process
(2) to replace any kind of structural steel and rebars. Use only fibrillated fibers of great length (25-40mm) at increased quantities (at least 1,5 Kg/m3) to replace traditional wire-mesh for slabs-on-grade.
Monofilament fibers? Just forget about it!!
(3) to control crack formation due to external stresses
(4) to increase compressive strength
(5) to reduce thickness of slabs-on-grade
(6) to avoid the obligation to abide by proper concrete practices.
Wall Ties -Making the cavity walls stable
Cavity wall is a load sharing system which use ties in specific patterns and provides extra resistance to weather conditions because of the cavity. The other main advantages of cavity walls include the thermal insulation, sound insulation, prevents moisture entering from outside and the structural stability. The material of construction or the structure of the cavity wall can vary, and the strength of these walls also depend upon the tying mechanism and tying product (wall tie) being used. Wall ties are the important member which significantly determines the stability of a cavity wall.
Builders use wall ties in cavity walls to hold the two walls together and stop them bulging or bowing. Horizontal cracking in brickwork, external rendering or building blocks can often be caused by the failure of cavity wall ties. In old properties it is common to find steel wall ties - these rust and corrode and have to be replaced. When the cavity wall ties corrode they expand to several times their original thickness, which causes the wall to crack at the mortar joints and often result in major damage and sometimes collapse of the wall.
The type and density of wall ties depends upon certain factors like the area of uncontrolled brickwork, the extent of exposure to wind, size of the cavity height of the building and the typical nature of the structure. If the wall ties used are not selected carefully, this can lead to damp penetration, the failure of the whole structure or even collapse.
If you are facing a wall tie failure, you should contact the specialist company. Their qualified surveyor will carry out a survey on the existing cavity wall ties using a metal detector, borescope and damp meter and by drilling into the wall at appropriate intervals he will view inside the cavity to check for cavity wall tie corrosion. He will also determine the extent of any external cracking and advice you of any appropriate repairs that are required or if the services of a structural engineer are needed. They will then issue a detailed report, our recommendations and estimate for all necessary cavity wall tie replacement and remedial work.
The several key elements of the wall survey includes location and approximate age of the property, width of cavity, detecting cracks and any signs of movement, cavity insulation, condition of ties, the pattern in which the ties are arranged, etc. The survey is carried by using specialist instruments like metal detectors and endoscopes, etc.
The detailed survey will help in identifying the exact problem and will provide a good starting point to combat wall ties failure problems by carefully selecting the appropriate repair strategy. The repair techniques that can be adopted may include the use of
• Structural wall ties and restraints
• Embedded wall stitching
• Strapping
• Structural Pinning
• Resin bonding or resin beam repairs – When the base material is not adequate or unable to take the stress of the mechanical member, then the resin helps in bonding the tie to the base material.
All the above mentioned repair strategies should always be carried out or supervised by a competent person as many of these require the old wall ties to be removed and replaced by new wall ties. Tapco HomeDry use a double expansion remedial cavity wall tie that is manufactured from corrosion resistant Austenitic 304 grade stainless steel tie bars with Neoprene sleeves. These cavity wall ties have a unique ‘tall-nut’ which when turned with a setting tool, rotates the whole tie bar, forcing the inner leaf sleeve to open and grip the masonry. At a factory set torque level, the end of the ‘tall nut’ shears away and the remaining nut is forced down the bar to expand the sleeve and grip the outer leaf.
Builders use wall ties in cavity walls to hold the two walls together and stop them bulging or bowing. Horizontal cracking in brickwork, external rendering or building blocks can often be caused by the failure of cavity wall ties. In old properties it is common to find steel wall ties - these rust and corrode and have to be replaced. When the cavity wall ties corrode they expand to several times their original thickness, which causes the wall to crack at the mortar joints and often result in major damage and sometimes collapse of the wall.
The type and density of wall ties depends upon certain factors like the area of uncontrolled brickwork, the extent of exposure to wind, size of the cavity height of the building and the typical nature of the structure. If the wall ties used are not selected carefully, this can lead to damp penetration, the failure of the whole structure or even collapse.
If you are facing a wall tie failure, you should contact the specialist company. Their qualified surveyor will carry out a survey on the existing cavity wall ties using a metal detector, borescope and damp meter and by drilling into the wall at appropriate intervals he will view inside the cavity to check for cavity wall tie corrosion. He will also determine the extent of any external cracking and advice you of any appropriate repairs that are required or if the services of a structural engineer are needed. They will then issue a detailed report, our recommendations and estimate for all necessary cavity wall tie replacement and remedial work.
The several key elements of the wall survey includes location and approximate age of the property, width of cavity, detecting cracks and any signs of movement, cavity insulation, condition of ties, the pattern in which the ties are arranged, etc. The survey is carried by using specialist instruments like metal detectors and endoscopes, etc.
The detailed survey will help in identifying the exact problem and will provide a good starting point to combat wall ties failure problems by carefully selecting the appropriate repair strategy. The repair techniques that can be adopted may include the use of
• Structural wall ties and restraints
• Embedded wall stitching
• Strapping
• Structural Pinning
• Resin bonding or resin beam repairs – When the base material is not adequate or unable to take the stress of the mechanical member, then the resin helps in bonding the tie to the base material.
All the above mentioned repair strategies should always be carried out or supervised by a competent person as many of these require the old wall ties to be removed and replaced by new wall ties. Tapco HomeDry use a double expansion remedial cavity wall tie that is manufactured from corrosion resistant Austenitic 304 grade stainless steel tie bars with Neoprene sleeves. These cavity wall ties have a unique ‘tall-nut’ which when turned with a setting tool, rotates the whole tie bar, forcing the inner leaf sleeve to open and grip the masonry. At a factory set torque level, the end of the ‘tall nut’ shears away and the remaining nut is forced down the bar to expand the sleeve and grip the outer leaf.
Steel Buildings May Resist Quakes
An engineer sets a model of a four-story building on his desk, adds two weights, and slides it slowly back and forth. The plywood-and-steel building sways smoothly. As he shortens and intensifies motions to mimic an earthquake, the model wriggles like molded jello, each floor moving differently from the one below it. Such complex motions challenge designers as they try to improve earthquake-resistant structures.
Yet engineers are no longer satisfied with buildings that avoid collapse during an earthquake - the basis of current 'life safety' earthquake steel building codes. They now want to design steel buildings that require only minor repairs and remain usable while repairs are made.
One of the more promising techniques, say some engineers, involves computerized machinery that adjusts a building's structure hundreds of times a second to offset the effects of ground vibrations - so-called active designs for earthquake resistance. Even if a building later had to be razed, the engineering was usually deemed successful if it held up long enough for people to escape unharmed.
Even in Japan, with its frequent strong temblors, 1971 building-code revisions only require that structures resist sudden collapse, according to Shizuo Hayashi, an engineering professor at the Tokyo Institute of Technology.
Two factors are prompting the shift toward 'performance based' designs
A similar estimate in 1988 put the probability at 60 percent by 2018, and only along the San Andreas and San Jacinto faults. Separate studies in last week's issue of Science magazine suggested that the region is long overdue for a series of quakes of Northridge-size magnitudes.
Designers have a variety of options for adding earthquake resistance to new or existing commercial steel buildings, much of it based on construction materials such as steel framing, steel-reinforced concrete, and properly braced and anchored wood framing for homes. While all of these techniques showed some flaws in the a few of the quakes of past years, they still can be effective when properly used, engineers say.
In addition, foundations can be mounted on shock absorbing 'base isolaters' made of springs or alternating layers of rubber and steel plate. The concept has been around for about 15 years, but it has caught on only within the last five years, as recent quakes have prompted planners to design and retrofit key steel buildings with isolaters.
Yet isolaters have shortcomings, engineers say. They are most effective on shorter steel buildings. Even then, buildings can slide off them under some circumstances. And their effectiveness on tall buildings is uncertain. They could actually tip over in a severe quake.
This is prompting researchers to look at active methods for earthquake resistance , particularly for tall buildings mostly made from steel. The principle is that they add energy to the building to counteract an earthquake's forces. This can be achieved in two ways. Adding steel braces to the sides of buildings that, through shock-absorbing hydraulics, can change the tension on a building's frame; and adding a movable multiton 'damper' to the top of a building that counteracts vibrations set up by an earthquake. The braces and dampers are controlled by a computer, which gathers information on the building's movements from strategically placed sensors.
Although the technique shows promise, it shouldn't be oversold, researchers say. First, it has not been tested by strong earthquakes -although a six-story experimental steel building in Tokyo performed well in three moderate earthquakes. Second, active measures rely on external power sources that can be vulnerable in a temblor. Moreover, cost remains a factor, although an active system would add only 3 to 5 percent to a commercial steel building.
Yet engineers are no longer satisfied with buildings that avoid collapse during an earthquake - the basis of current 'life safety' earthquake steel building codes. They now want to design steel buildings that require only minor repairs and remain usable while repairs are made.
One of the more promising techniques, say some engineers, involves computerized machinery that adjusts a building's structure hundreds of times a second to offset the effects of ground vibrations - so-called active designs for earthquake resistance. Even if a building later had to be razed, the engineering was usually deemed successful if it held up long enough for people to escape unharmed.
Even in Japan, with its frequent strong temblors, 1971 building-code revisions only require that structures resist sudden collapse, according to Shizuo Hayashi, an engineering professor at the Tokyo Institute of Technology.
Two factors are prompting the shift toward 'performance based' designs
A similar estimate in 1988 put the probability at 60 percent by 2018, and only along the San Andreas and San Jacinto faults. Separate studies in last week's issue of Science magazine suggested that the region is long overdue for a series of quakes of Northridge-size magnitudes.
Designers have a variety of options for adding earthquake resistance to new or existing commercial steel buildings, much of it based on construction materials such as steel framing, steel-reinforced concrete, and properly braced and anchored wood framing for homes. While all of these techniques showed some flaws in the a few of the quakes of past years, they still can be effective when properly used, engineers say.
In addition, foundations can be mounted on shock absorbing 'base isolaters' made of springs or alternating layers of rubber and steel plate. The concept has been around for about 15 years, but it has caught on only within the last five years, as recent quakes have prompted planners to design and retrofit key steel buildings with isolaters.
Yet isolaters have shortcomings, engineers say. They are most effective on shorter steel buildings. Even then, buildings can slide off them under some circumstances. And their effectiveness on tall buildings is uncertain. They could actually tip over in a severe quake.
This is prompting researchers to look at active methods for earthquake resistance , particularly for tall buildings mostly made from steel. The principle is that they add energy to the building to counteract an earthquake's forces. This can be achieved in two ways. Adding steel braces to the sides of buildings that, through shock-absorbing hydraulics, can change the tension on a building's frame; and adding a movable multiton 'damper' to the top of a building that counteracts vibrations set up by an earthquake. The braces and dampers are controlled by a computer, which gathers information on the building's movements from strategically placed sensors.
Although the technique shows promise, it shouldn't be oversold, researchers say. First, it has not been tested by strong earthquakes -although a six-story experimental steel building in Tokyo performed well in three moderate earthquakes. Second, active measures rely on external power sources that can be vulnerable in a temblor. Moreover, cost remains a factor, although an active system would add only 3 to 5 percent to a commercial steel building.