The purpose of grouting is to provide permanent protection to the post-tensioned steel against corrosion and to develop bond between the Prestressing cables and the surrounding structural concrete.Grouting shall be carried out as early as possible, but generally not later than two weeks of stressing.Whenever this stipulation cannot be completed with for unavoidable reasons adequate temporary protection of the cables against corrosion by methods or products, which will not impair the ultimate adherence of the injected grout shall be ensured till grouting.
Material
1. Water : Only Clean potable water free from impurities shall be used.
2. Cement : Ordinary port land cement 43Grade shall be used. It should be as fresh as possible and free from any lumps.
3. Admixture : Non-shrink powder compound.
Equipments
1. Grout Mixer Mechanical type
2. Grout Pump J-600
3. Grout Screen
4. Connection and air vents
5. Generator
6. Thermometer, Stopwatch etc.
Procedure of the Grout
1)After measuring the slip of 24hrs, the extended cables shall be cut off
50mm away from bearing plates.
2) Cement mortar of 1:1 ratio is applied over the Bearing Plates on both ends of girders to prevent the leakage of Grout. Grouting operation shall be commenced after two days of sealing the ends.
3) Water cement ratio should be as low as possible consistent with workability. This ratio is 0.42 (not more than 0.45 as per MOST,P-677) proportions of material shall be based on field trials made on the Grout before commencement of grouting. As per specifications, the temperature of the Grout maintained at 250C by adding ice into water if necessary.
4) Water shall be poured in to the mixer with Port land cement and admixture is added into it. Mixing shall be continued for duration to obtain uniform and thoroughly blended Grout. Grout shall be continuously agitated and then pour into another tank after passing through the screen.
5) Ducts shall be flushed with water for cleaning as well as for wetting the surface of the duct walls.
6) The water in the duct shall be blown out with compress air.
Injection Of Grout:-
1) After mixing of Grout, all connections from tank to pump and pump to inlet shall be checked.
2) The grout shall be allowed to flow freely from the other end until the consistency of the grout at this end is the same as that of the Grout at the injection end.
3) When the Grout flows at the other end, it shall be closed off and grouting is continued so that pressure commenced, full injection pressure at about 5 kg/cm2 shall be maintained for at least one minute before closing the injection pipes.
4) If there is leakage observed at any of ends the grouting operation shall be discontinued and the entire duct flushed with high-pressure water. Grout not used within 30minutes of mixing shall be rejected.
6) Check the Compressive strength of the cubes for the grout in 10 cm cubes for 7 days, which should not be less than 17 Mpa.
7) Grouting record for each cable shall be maintained as per Perform in MOST.
Tuesday, December 1, 2009
Low cost in construction
Low Cost building is a new concept which deals with effective budgeting and following of techniques which help in reducing the cost construction through the use of locally available materials along with improved skills and technology without sacrificing the strength, performance and life of the structure.There is huge misconception that low cost housing is suitable for only sub standard works and they are constructed by utilizing cheap building materials of low quality.The fact is that Low cost housing is done by proper management of resources.Economy is also achieved by postponing finishing works or implementing them in phases.
Building Cost
The building construction cost can be divided into two parts namely:
Building material cost : 65 to 70 %
Labour cost : 65 to 70 %
Now in low cost housing, building material cost is less because we make use of the locally available materials and also the labour cost can be reduced by properly making the time schedule of our work. Cost of reduction is achieved by selection of more efficient material or by an improved design.
Areas from where cost can be reduced are:-
1) Reduce plinth area by using thinner wall concept.Ex.15 cms thick solid concrete block wall.
2) Use locally available material in an innovative form like soil cement blocks in place of burnt brick.
3) Use energy efficiency materials which consumes less energy like concrete block in place of burnt brick.
4) Use environmentally friendly materials which are substitute for conventional building components like use R.C.C. Door and window frames in place of wooden frames.
5) Preplan every component of a house and rationalize the design procedure for reducing the size of the component in the building.
6) By planning each and every component of a house the wastage of materials due to demolition of the unplanned component of the house can be avoided.
7) Each component of the house shall be checked whether if it’s necessary, if it is not necessary, then that component should not be used.
Cost reduction through adhoc methods
Foundation
Normally the foundation cost comes to about 10 to 15% of the total building and usually foundation depth of 3 to 4 ft. is adopted for single or double store building and also the concrete bed of 6″(15 Cms.) is used for the foundation which could be avoided.
It is recommended to adopt a foundation depth of 2 ft.(0.6m) for normal soil like gravely soil, red soils etc., and use the uncoursed rubble masonry with the bond stones and good packing. Similarly the foundation width is rationalized to 2 ft.(0.6m).To avoid cracks formation in foundation the masonry shall be thoroughly packed with cement mortar of 1:8 boulders and bond stones at regular intervals.
It is further suggested adopt arch foundation in ordinary soil for effecting reduction in construction cost up to 40%.This kind of foundation will help in bridging the loose pockets of soil which occurs along the foundation.
In the case black cotton and other soft soils it is recommend to use under ream pile foundation which saves about 20 to 25% in cost over the conventional method of construction.
Plinth
It is suggested to adopt 1 ft. height above ground level for the plinth and may be constructed with a cement mortar of 1:6. The plinth slab of 4 to 6″ which is normally adopted can be avoided and in its place brick on edge can be used for reducing the cost. By adopting this procedure the cost of plinth foundation can be reduced by about 35 to 50%.It is necessary to take precaution of providing impervious blanket like concrete slabs or stone slabs all round the building for enabling to reduce erosion of soil and thereby avoiding exposure of foundation surface and crack formation.
Walling
Wall thickness of 6 to 9″ is recommended for adoption in the construction of walls all-round the building and 41/2 ” for inside walls. It is suggested to use burnt bricks which are immersed in water for 24 hours and then shall be used for the walls
Rat – trap bond wall
It is a cavity wall construction with added advantage of thermal comfort and reduction in the quantity of bricks required for masonry work. By adopting this method of bonding of brick masonry compared to traditional English or Flemish bond masonry, it is possible to reduce in the material cost of bricks by 25% and about 10to 15% in the masonry cost. By adopting rat-trap bond method one can create aesthetically pleasing wall surface and plastering can be avoided.
Concrete block walling
In view of high energy consumption by burnt brick it is suggested to use concrete block (block hollow and solid) which consumes about only 1/3 of the energy of the burnt bricks in its production. By using concrete block masonry the wall thickness can be reduced from 20 cms to 15 Cms. Concrete block masonry saves mortar consumption, speedy construction of wall resulting in higher output of labour, plastering can be avoided thereby an overall saving of 10 to 25% can be achieved.
Soil cement block technology
It is an alternative method of construction of walls using soil cement blocks in place of burnt bricks masonry. It is an energy efficient method of construction where soil mixed with 5% and above cement and pressed in hand operated machine and cured well and then used in the masonry. This masonry doesn’t require plastering on both sides of the wall. The overall economy that could be achieved with the soil cement technology is about 15 to 20% compared to conventional method of construction.
Doors and windows
It is suggested not to use wood for doors and windows and in its place concrete or steel section frames shall be used for achieving saving in cost up to 30 to 40%.Similiarly for shutters commercially available block boards, fibre or wooden practical boards etc., shall be used for reducing the cost by about 25%.By adopting brick jelly work and precast components effective ventilation could be provided to the building and also the construction cost could be saved up to 50% over the window components.
Lintals and Chajjas
The traditional R.C.C. lintels which are costly can be replaced by brick arches for small spans and save construction cost up to 30 to 40% over the traditional method of construction. By adopting arches of different shapes a good architectural pleasing appearance can be given to the external wall surfaces of the brick masonry.
Roofing
Normally 5″(12.5 cms) thick R.C.C. slabs is used for roofing of residential buildings. By adopting rationally designed insitu construction practices like filler slab and precast elements the construction cost of roofing can be reduced by about 20 to 25%.
Filler slabs
They are normal RCC slabs where bottom half (tension) concrete portions are replaced by filler materials such as bricks, tiles, cellular concrete blocks, etc.These filler materials are so placed as not to compromise structural strength, result in replacing unwanted and nonfunctional tension concrete, thus resulting in economy. These are safe, sound and provide aesthetically pleasing pattern ceilings and also need no plaster.
For more on filler materials check Filler Materials Used in Concrete
Jack arch roof/floor
They are easy to construct, save on cement and steel, are more appropriate in hot climates. These can be constructed using compressed earth blocks also as alternative to bricks for further economy.
Ferrocement channel/shell unit
Provide an economic solution to RCC slab by providing 30 to 40% cost reduction on floor/roof unit over RCC slabs without compromising the strength. These being precast, construction is speedy, economical due to avoidance of shuttering and facilitate quality control.
Finishing Work
The cost of finishing items like sanitary, electricity, painting etc., varies depending upon the type and quality of products used in the building and its cost reduction is left to the individual choice and liking.
Building Cost
The building construction cost can be divided into two parts namely:
Building material cost : 65 to 70 %
Labour cost : 65 to 70 %
Now in low cost housing, building material cost is less because we make use of the locally available materials and also the labour cost can be reduced by properly making the time schedule of our work. Cost of reduction is achieved by selection of more efficient material or by an improved design.
Areas from where cost can be reduced are:-
1) Reduce plinth area by using thinner wall concept.Ex.15 cms thick solid concrete block wall.
2) Use locally available material in an innovative form like soil cement blocks in place of burnt brick.
3) Use energy efficiency materials which consumes less energy like concrete block in place of burnt brick.
4) Use environmentally friendly materials which are substitute for conventional building components like use R.C.C. Door and window frames in place of wooden frames.
5) Preplan every component of a house and rationalize the design procedure for reducing the size of the component in the building.
6) By planning each and every component of a house the wastage of materials due to demolition of the unplanned component of the house can be avoided.
7) Each component of the house shall be checked whether if it’s necessary, if it is not necessary, then that component should not be used.
Cost reduction through adhoc methods
Foundation
Normally the foundation cost comes to about 10 to 15% of the total building and usually foundation depth of 3 to 4 ft. is adopted for single or double store building and also the concrete bed of 6″(15 Cms.) is used for the foundation which could be avoided.
It is recommended to adopt a foundation depth of 2 ft.(0.6m) for normal soil like gravely soil, red soils etc., and use the uncoursed rubble masonry with the bond stones and good packing. Similarly the foundation width is rationalized to 2 ft.(0.6m).To avoid cracks formation in foundation the masonry shall be thoroughly packed with cement mortar of 1:8 boulders and bond stones at regular intervals.
It is further suggested adopt arch foundation in ordinary soil for effecting reduction in construction cost up to 40%.This kind of foundation will help in bridging the loose pockets of soil which occurs along the foundation.
In the case black cotton and other soft soils it is recommend to use under ream pile foundation which saves about 20 to 25% in cost over the conventional method of construction.
Plinth
It is suggested to adopt 1 ft. height above ground level for the plinth and may be constructed with a cement mortar of 1:6. The plinth slab of 4 to 6″ which is normally adopted can be avoided and in its place brick on edge can be used for reducing the cost. By adopting this procedure the cost of plinth foundation can be reduced by about 35 to 50%.It is necessary to take precaution of providing impervious blanket like concrete slabs or stone slabs all round the building for enabling to reduce erosion of soil and thereby avoiding exposure of foundation surface and crack formation.
Walling
Wall thickness of 6 to 9″ is recommended for adoption in the construction of walls all-round the building and 41/2 ” for inside walls. It is suggested to use burnt bricks which are immersed in water for 24 hours and then shall be used for the walls
Rat – trap bond wall
It is a cavity wall construction with added advantage of thermal comfort and reduction in the quantity of bricks required for masonry work. By adopting this method of bonding of brick masonry compared to traditional English or Flemish bond masonry, it is possible to reduce in the material cost of bricks by 25% and about 10to 15% in the masonry cost. By adopting rat-trap bond method one can create aesthetically pleasing wall surface and plastering can be avoided.
Concrete block walling
In view of high energy consumption by burnt brick it is suggested to use concrete block (block hollow and solid) which consumes about only 1/3 of the energy of the burnt bricks in its production. By using concrete block masonry the wall thickness can be reduced from 20 cms to 15 Cms. Concrete block masonry saves mortar consumption, speedy construction of wall resulting in higher output of labour, plastering can be avoided thereby an overall saving of 10 to 25% can be achieved.
Soil cement block technology
It is an alternative method of construction of walls using soil cement blocks in place of burnt bricks masonry. It is an energy efficient method of construction where soil mixed with 5% and above cement and pressed in hand operated machine and cured well and then used in the masonry. This masonry doesn’t require plastering on both sides of the wall. The overall economy that could be achieved with the soil cement technology is about 15 to 20% compared to conventional method of construction.
Doors and windows
It is suggested not to use wood for doors and windows and in its place concrete or steel section frames shall be used for achieving saving in cost up to 30 to 40%.Similiarly for shutters commercially available block boards, fibre or wooden practical boards etc., shall be used for reducing the cost by about 25%.By adopting brick jelly work and precast components effective ventilation could be provided to the building and also the construction cost could be saved up to 50% over the window components.
Lintals and Chajjas
The traditional R.C.C. lintels which are costly can be replaced by brick arches for small spans and save construction cost up to 30 to 40% over the traditional method of construction. By adopting arches of different shapes a good architectural pleasing appearance can be given to the external wall surfaces of the brick masonry.
Roofing
Normally 5″(12.5 cms) thick R.C.C. slabs is used for roofing of residential buildings. By adopting rationally designed insitu construction practices like filler slab and precast elements the construction cost of roofing can be reduced by about 20 to 25%.
Filler slabs
They are normal RCC slabs where bottom half (tension) concrete portions are replaced by filler materials such as bricks, tiles, cellular concrete blocks, etc.These filler materials are so placed as not to compromise structural strength, result in replacing unwanted and nonfunctional tension concrete, thus resulting in economy. These are safe, sound and provide aesthetically pleasing pattern ceilings and also need no plaster.
For more on filler materials check Filler Materials Used in Concrete
Jack arch roof/floor
They are easy to construct, save on cement and steel, are more appropriate in hot climates. These can be constructed using compressed earth blocks also as alternative to bricks for further economy.
Ferrocement channel/shell unit
Provide an economic solution to RCC slab by providing 30 to 40% cost reduction on floor/roof unit over RCC slabs without compromising the strength. These being precast, construction is speedy, economical due to avoidance of shuttering and facilitate quality control.
Finishing Work
The cost of finishing items like sanitary, electricity, painting etc., varies depending upon the type and quality of products used in the building and its cost reduction is left to the individual choice and liking.
Friday, November 20, 2009
Bridge construction types
Beams:Cross-section beams used in buildings may vary in size. Some are solid or hollow. Below are three different size beams. The first one box beam section, the second one beam section and the third one I have L section beam. Solid bars are hollow with huge smiles. As you strength and hardness of a special section bars below. He beams as strong as large, but too many can be lighter. We a good power / weight ratio as described in can.
Reinforced concrete beams
Solid doors and windows on buildings used as pieces support horizontal beams. These are called lintels. Engaged in concrete reinforced with steel rods These lintels are. Steel bars are usually placed under the neutral axis. More than one material is a combination of reinforced concrete composite materials. When under stress increased the strength of steel concrete increases.
Concrete is very strong in compression but weak in tension. One of the qualities of concrete as we describe it.
Task
1. Card and glue used three times. Test structural strength and load resistance (compression and tension in tension) for the separate beams. Between two desks or chairs we achieve this can keep time. If weight or suspended beams, we finally witness must be able to change the size of beams is kept on the top. He gives a sign of weakness. They fold or bend, depending on how much weight is hanging from them, maybe.
2. Test rapidly with heavy weight one tree. Although weight loss and weight recorded episodes of both structural size hanging if time. Place in a spreadsheet or change these results describe a graph with notes and record your results.
You watch episodes of one Newton meters or may consider using line test.
3. Once you finish your experiment illustrated folding beam or by any means the longest length of time without crumpling on was heavy weights.
4. Why was once the other two types of structurally stronger explain?
5. Such architectural structure which is used once to send?
6. With efforts to increase the power of additional beam map? Remember many additional cards, the time surcharge. The weight ratio with low power will be over.
Wednesday, November 18, 2009
Types of construction materials
"Sticky, glue and gelatin
"Air conditioning and Refrigeration Equipment & Supplies
"Aluminum and its products
"Balcony railings
"Swimming in the system, panels, Bathtubs bath
"Equipment and bathroom items
Bristles are brushes, brooms, and related products
"Cast iron ornamental railings
Binder
Cement "& Tools
"Clay Bricks
»Compoundwall railing
Construction "
"Dies, castings and forgings
"Entrance banister
"Escalators, lifts, chair lifts and removal tool
"Fire Front Products
"Garden Furniture
"General Construction Equipment Operators
"Granite, marble and slate
"Registration Tool
Products "Iron, hardware and related
"Laterna railing
"Loading and off equipment
"Merchant Merchant
Nuts "and bolts, nails, screws and needles
"Other Miscellaneous Building & Construction
"Paints, varnishes, and powder
"Pipes, pipe fittings and flanges
"Plastic, PVC and Pu Products
"Process Control Equipment
"Security Locks
Plumbing "
"Security systems
"Spiral staircase railings
"Staircase railing
"Steel, stainless steel and related products
"Test Equipment and Machinery
"Wall and floor tiles
"Wood flooring, sawn timber, veneer and laminate
"Zinc Tool
"Air conditioning and Refrigeration Equipment & Supplies
"Aluminum and its products
"Balcony railings
"Swimming in the system, panels, Bathtubs bath
"Equipment and bathroom items
Bristles are brushes, brooms, and related products
"Cast iron ornamental railings
Binder
Cement "& Tools
"Clay Bricks
»Compoundwall railing
Construction "
"Dies, castings and forgings
"Entrance banister
"Escalators, lifts, chair lifts and removal tool
"Fire Front Products
"Garden Furniture
"General Construction Equipment Operators
"Granite, marble and slate
"Registration Tool
Products "Iron, hardware and related
"Laterna railing
"Loading and off equipment
"Merchant Merchant
Nuts "and bolts, nails, screws and needles
"Other Miscellaneous Building & Construction
"Paints, varnishes, and powder
"Pipes, pipe fittings and flanges
"Plastic, PVC and Pu Products
"Process Control Equipment
"Security Locks
Plumbing "
"Security systems
"Spiral staircase railings
"Staircase railing
"Steel, stainless steel and related products
"Test Equipment and Machinery
"Wall and floor tiles
"Wood flooring, sawn timber, veneer and laminate
"Zinc Tool
Tuesday, November 17, 2009
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