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Friday, September 7, 2012

steps on How to do New floor screeding

for a new cement/sand floor screeding, its better for the floor if the mix ratio can be 1:4, 1 part cement to 4 parts sand.  if you are not planing to put over load goods or things there is no need for reinforcement, the thickness of the screeding slab can be 50mm or 2 inch thick.
Step 1; do floor blending with a good earth compactor.

Step 2; Using a tube level, bench mark every 2m or 6 feets so that the whole floor is even

Step 3; if your not using a pipe, use the mixed cement and make a trench with a ruler section

 now that there are two side with same height as the above pic, and center is with no cement mix.
Step 4; pour the cement mortar and spread it and using a trowel you can fine smooth it.

Source; www.yd-mv.com

Friday, August 17, 2012

How to put up a wood partition

25x15 feet Space to be divided into two rooms, rooms with 8 feet high timber partition with two panel doors to each room.


Step 1. Mark two point on both side of the rooms where you want the room to be divided, than draw a line on the floor, after you know your line, place solid timber of 2x1.5 inch on the line than screw to the floor, 3 feet apart, so that it securely anchors to the floor. 

Step 2. Erect timber each 2 feet apart to a height of 8 feet, than place the top timber so that the frame is now completed, add reinforcing timber in between each erected timber at a height of 4 feet.

 Step 3. Nail the 3mm ply wood with 1inch nail, hammer the nails 6inch apart on the sides, and for the center spaces, 1 feet part.



 Step 4. Fix the door frames the partition frames.





Step 5. Fix the panel door and insert lock.


Friday, August 10, 2012

Factors effects Divers while Underwater Concrete




1. Effect of tidal flow
The most important limiting factor which adversely affects a diver's work is the velocity of water flow. A flow of 1 knot has roughly the same effect on a diver as that of an 80 km/h wind acting on a man on land. The maximum tidal flow in which a diver can work effectively is, not surprisingly, about "1 knot. The ability to work in a strong tidal flow is dependent on the work task, the work location and adjacent physical support available to the diver.

2. Visual inspection

A diver looking, as he does, through layers of air, glass and water observes objects apparently larger and closer than they actually are. He is therefore liable to report incorrect dimen-sions if he relies solely on observation, and he should always use a sea-bed ruler. A spirit-level may be used to establish levels in shallow water.


3.Poor visibility
In rivers which run through highly populated or industrialized areas, visibility is often very poor. The converse usually applies in sparsely populated areas. Similarly, in coastal areas near river estuaries, the outflow of polluted rivers may adversely affect visibility many miles offshore although the prospect of good visibility improves further offshore. Apart from pollution caused by man, sand from the sea-bed brought into suspension by storms can reduce visibility to a few centimeters even well offshore. After a few days of good weather this can change to give a visibility in excess of 30m. In poor visibility, high- candlepower lights illuminate only the particles in suspension so the diver sees myriads of bright reflections from the particles. Special low-candlepower lights are available for close inspection in poor visibility. In areas of permanent low visibility, tactile measuring devices are invaluable and the diver's fingers become his eyes.

Underwater floodlights are likely to be useless in shallow water where daylight has not penetrated. The effective use of floodlights is primarily limited to night work or at intakes and other areas where natural light cannot penetrate.


4. The underwater season
In the summer months, weeds and other marine growth are at their most prolific, particularly in shallow coastal waters. Inspection of outfalls and other structures is therefore best carried out in the early spring.

5. Fatigue
Breathing underwater involves appreciable effort. The muscles of the rib cage which draw air into the lungs have to work harder to ventilate the lungs with the denser air. With the demand-valve systems, some effort is also required to activate the tilt valve. The effort required to swim underwater is heavy and trials have shown that a diver in standard diving apparatus uses approximately the same effort when walking as the under- water swimmer. Two hours is considered the maximum time a diver can work efficiently using a demand-valve breathing system. Provided that he is working in one area, 4 h duration is possible in helmet gear.


6.Sickness
Of necessity, divers are required to have a high degree of physical fitness and, generally, they are very rarely ill. However, working in cold water and experiencing temperature changes exposes them to the common cold. This can be serious since the presence of mucus in the Eustachian tubes can prevent 'clearing his ears'. He is then unable to balance the pressure across his ear drums and the drums are forced inwards. The forcing can cause damage or infection of the ear. Consequently, divers should not dive with a head cold.





Sunday, July 29, 2012

How to do toilet floor

Top of the slab
 Courtesy of YD Works
Toilet to be constructed on top of a slab with dimension 4 feet x 5 feet, so for this job, there is a 4inch dia UPVC Pipe drilled in to the slab, make sure you have the correct gap between the wall the pipe.

Bench marked for floor screeding
Courtesy of YD Works
Point "A" is the floor drain after drilling hole of 2inch with a pipe fitted, than find the top level of drain and find the top level of "B", make sure the levels differs by 12mm, so that it creates a slop. "C" is where WC is to be fitted.

Floor screeding completed
courtesy of YD Works
ones the floor screeding is completed, now that there is a slop of 12mm from one end to the drain, now that its ready for tiles work

floor tiles completed

Wall Tiles completed
after the tiles is completed, fill the gaps with white water resisting cement. after all the caps been filled, fit the WC on top of the pipe and secure the WC with sealant.

Wednesday, July 25, 2012

How to fabricate a steel door

First cut the pipes to the desired size. Then place the pipes on a flat surface, give each joint a tech weld while placing the pieces.
Once all the welds r completed, start butt welding it joint by joint. Apply red oxide paint once grinding is done. Then fix the wheels. And fit it on the frame.


Tuesday, July 24, 2012

How to prepare concrete staircase form work or shuttering work

The stair case which has 6 steps before landing, width of the stair case 850mm, step height 176mm, steps 200mm.  stair case step one start after floor height of 150mm

Drawing of sample stair case

leveling step one of form work

side view of staircase shuttering work

stair case bottom support of shuttering/form work

The most important thing to take note while preparing form work is that; 
1. The ply wood is secure and timber is enough to support concrete weight and vibration while pouring, so the last pic shows the bracing given to support the concrete. the pics were taken few hours before completing the whole form-work.
2. Making sure the first step is level, using a sprite level, so that it ensures the fact that next steps will be leveled. 
3. Take accurate measurements from the last end of the step one to the grid line, and top end of the step to the grid line, in this sample it measure 820mm at bottom and top against the grid line.
4. for easy construction of form work, use 2inch x 1.5inch straight timbers, and nail or screw them together. 


concrete poured to stair case form work and left for curing

setting up cantilever beam for landing



Wednesday, May 2, 2012

why two meters deep excavation is a failure for pile cap


Excavation of shallow foundation 2m
courtesy of yd-mv.com



Type of building work
This involves construction of a 4-storey flatted factory (with no basement) located between two existing single story terrace houses which were founded on small diameter bored piles.

What went wrong
Timber planks were used to support a 2m deep excavation to construct a pilecap adjacent to an existing single story house. The ground condition was poor, comprising of soft marine clay and the timber planks to support the excavation was shoddily done.

Shoddy timber planks to support

The timber planks were not effective in resisting the earth pressure and gave way, resulting in movement of the marine clay beneath the adjacent house. The ground movement cracked the small diameter bored pile supporting the adjacent house causing the entire front section of the adjacent house to collapse.


Learning points
a) Every construction project, whether big or small should be given due attention.
b) Properly designed temporary earth-retaining structures should be provided to protect the sides of the excavation, even for shallow excavation. The design should take into consideration the effects of inclement weather and presence of foundation of existing buildings.
c) Extra precautionary measures should be taken when working close to existing building.

Monday, April 30, 2012

How to install pile to foundation




The installation process and method of installations are equally important factors as of the design process of pile foundations. In this section we will discuss the two main types of pile installation methods; installation by pile hammer and boring by mechanical auger. 

In order to avoid damages to the piles, during design, installation Methods and installation equipment should be carefully selected. If installation is to be carried out using pile-hammer, then the following factors.

should be taken in to consideration: 
  • the size and the weight of the pile 
  • the driving resistance which has to be overcome to achieve the design penetration 
  • the available space and head room on the site 
  • the availability of cranes and 
  • the noise restrictions which may be in force in the locality. 

Pile driving methods (displacement piles)
Methods of pile driving can be categorised as follows:
  1. Dropping weight
  2. Explosion
  3. Vibration
  4. Jacking (restricted to micro-pilling)
  5. Jetting 


Drop hammers 
A hammer with approximately the weight of the pile is raised a suitable height in a guide and released to strike the pile head. This is a simple form of hammer used in conjunction with light frames and test piling, where it may be uneconomical to bring a steam boiler or compressor on to a site to drive very limited number of piles.
 
There are two main types of drop hammers:  
  1. Single-acting steam or compressed-air hammers; comprise a massive weight in the form of a cylinder. Steam or compressed air admitted to the cylinder raises it up the fixed piston rod. At the top of the stroke, or at a lesser height which can be controlled by the operator, the steam is cut off and the cylinder falls freely on the pile helmet. 
  2. Double-acting pile hammers; can be driven by steam or compressed air. A pilling frame is not required with this type of hammer which can be attached to the top of the pile by leg-guides, the pile being guided by a timber framework. When used with a pile frame, back guides are bolted to the hammer to engage with leaders, and only short leg-guides are used to prevent the hammer from moving relatively to the top of the pile. Double-acting hammers are used mainly for sheet pile driving. 





Diesel hammers 
Also classified as single and double-acting, in operation, the diesel hammer employs a ram which is raised by explosion at the base of a cylinder. Alternatively, in the case of double-acting diesel hammer, a vacuum is created in a separate annular chamber as the ram moves upward, and assists in the return of the ram, almost doubling the output of the hammer over the single-acting type. In favourable ground conditions, the diesel hammer provide an efficient pile driving capacity, but they are not effective for all types of ground. 

Pile driving by vibrating
Vibratory hammers are usually electrically powered or hydraulically powered and consists of contra-rotating eccentric masses within a housing attaching to the pile head. The amplitude of the vibration is sufficient to break down the skin friction on the sides of the pile. Vibratory methods are best suited to sandy or
gravelly soil.

Jetting: to aid the penetration of piles in to sand or sandy gravel, water jetting may be employed. However, the method has very limited effect in firm to stiff clays or any soil containing much coarse gravel, cobbles, or boulders.
complete vibration hammer kit, just need a heavy excavator to attach the hammer


Boring methods ( non-displacement piles) 

Continuous Flight Auger (CFA) 
An equipment comprises of a mobile base carrier fitted with a hollow-stemmed flight auger which is rotated into the ground to required depth of pilling. To form  the pile, concrete is placed through the flight auger as it is withdrawn from the ground. The auger is fitted with protective cap on the outlet at the base of the central tube and is rotated into the ground by the top mounted rotary hydraulic motor which runs on a carrier attached to the mast. On reaching the required depth, highly workable concrete is pumped through the hollow stem of the auger, and under the pressure of the concrete the protective cap is detached. While rotating the auger in the same direction as during the boring stage, the spoil is expelled vertically as the auger is withdrawn and the pile is formed by filling with concrete.In this process, it is important that rotation of the auger and flow of concrete is matched that collapse of sides of the hole above concrete on lower flight of auger is avoided. This may lead to voids in filled with soil in concrete. 

The method is especially effective on soft ground and enables to install a variety of bored piles of various diameters that are able to penetrate a multitude of soil conditions. Still, for successful operation of rotary auger the soil must be reasonably free of tree roots, cobbles, and boulders, and it must be self-supporting.

During operation little soil is brought upwards by the auger that lateral stresses is maintained in the soil and voiding or excessive loosening of the soil minimise. However, if the rotation of the auger and the advance of the auger is not matched, resulting in removal of soil during drilling-possibly leading to collapse of the side of the hole. 



Underreaming 
A special feature of auger bored piles which is sometimes used to enable to exploit the bearing capacity of suitable strata by providing an enlarged base. The soil has to be capable of standing open unsupported to employ this technique. Stiff and to hard clays, such as the London clay, are ideal. In its closed position, the underreaming tool is fitted inside the straight section of a pile shaft, and then expanded at the bottom of the pile to produce the underream Normally, after installation and before concrete is casted, a man carrying cage is lowered and the shaft and the underream of the pile is inspected. 


C.H.D.P 
Continuous helical displacement piles: a short, hollow tapered steel former complete with a larger diameter helical flange, the bullet head is fixed to a hallow drill pipe which is connected to a high torque rotary head running up and down the mast of a special rig. A hollow cylindrical steel shaft sealed at the 
lower end by a one-way valve and fitted with triangular steel fins is pressed into the ground by a hydraulic ram. There are no vibrations. Displaced soil is compacted in front and around the shaft. Once it reaches the a suitably resistant stratum the shaft is rotated. The triangular fins either side of its leading edge carve out a conical base cavity. At the same time concrete is pumped down the centre of the shat and through the one-way valve. Rotation of the fins is calculated so that as soil is pushed away from the pile base it is simultaneously replaced by in-flowing concrete. Rates of push, rotation and concrete injection are all controlled by an onboard computer. Torque on the shaft is also measured by the computer. When torque levels reach a constant low value the base in formed. The inventors claim that the system can install typical pile in 12 minute. A typical 6m long pile with an 800mm diameter base and 350mm shaft founded on moderately dense gravel beneath soft overlaying soils can achieve an ultimate capacity of over 200t. The pile is suitable for embankments, hard standing supports and floor slabs, where you have a soft silty layer over a gravel strata.



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Saturday, April 28, 2012

How to select the type of light reflector for home



Electric (Artificial) Lighting


Lamp types
(1) Incandescent lamps produce a warm light,are inexpensive and easy to use but have limited lumination per watt (20 to 40) and a short life. Normal voltage lamps produce a point source of light. Most common shapes are A, R, and PAR. Low voltage lamps pro- duce a very small point of intense brightness that can be focused into a precise beam of light (for merchandise or art).These are usually PAR shapes or designed to fit into a parabolic reflector. Sizes are designated in 1⁄8 inch of the widest part of lamp.Tungsten-Halogen (quartz) and low voltage are a special type of incandescent. Quartz is another type of incandescent that has high-intensity white light with slightly longer life.

(2) Gaseous discharge lamps produce light by passing electricity through a gas. These lamps require a ballast to get the lamp started and then to control the current.

  1. Fluorescent lamps produce a wide, linear, diffuse light source that is well-suited to spreading light downward to the working surfaces of desks or displays in a commercial environment with normal ceiling heights (8′ to 12′). Lamps are typically 17, 25, or 32 watts. The deluxe lamps have good color-rendering characteristics and can be chosen to favor the cool (blue) or the warm (red) end of the spectrum. Dimmers for fluorescent are expensive. Fluorescent lamps produce more light per watt of energy (70–85 lumens/watt) than incandescent; thus operating costs are low.The purchase price and length of life of fluorescent lamps are greater than for incandescent and less than for HID. Four-feet lamp lengths utilize 40 watts and are most common. Designations are F followed by wattage, shape, size, color, and a form factor.
  2. High-intensity discharge (HID) lamps can be focused into a fairly good beam of light. These lamps, matched with an appropriate fixture are well-suited to beaming light down to the working place from a high ceiling (12′ to 20′).Dimming HID lamps is difficult. The lamps are expensive but produce a lot of light and last a long time. If there is a power interruption, HID lamps will go out and cannot come on again for about 10 minutes while they cool down.Therefore,in an installation of HID lamps, a few incandescent or fluorescent lamps are needed to provide backup lighting. Since they operate at high temperatures, they would be a poor choice for low ceilings, wall sconces, or any other close proximity light source. They would also be a poor choice in assemblies and other occupancy where power outages could cause panic. Mercury vapor (MV; the bluish street lamps). Because they emit a blue-green light, they are excellent for highlighting foliage, green copper exteriors, and certain signage. Deluxe version is warmer. 35 to 65 lumens/watt. This is not much used anymore. Metal halide (MH) are often ice blue cool industrial-looking lamps. Deluxe color rendering bulbs are 50 to 400 watts, and almost as good as deluxe fluorescent for a warmer effect. Efficiency is 80 lumens/watt. High-pressure sodium (HPS) produces a warm golden yellow light often used for highways. Bulbs are 35 to 400 watts. Deluxe color rendering is almost as cool as deluxe fluorescent for a cooler effect. Efficiency is 100 lumens/watt. Low-pressure sodium (LPS) produces a yellow color which makes all colors appear in shades of grey. They are excellent for promoting plant growth indoors. Bulbs are typically 35 to 180 watts. Used for parking lots and roadways. Efficiency is 150 lumens/watt.
  3. Cold cathode (neon) has a color dependent on the gas and the color of the tube. Can be most any color. Does not give off enough light for detailed visual tasks, but does give off enough light for attracting attention, indoors or out.



Types of reflectors

Common types of reflectors


Lighting systems and fixture types

Note: Costs include lamps, fixture, and installation labor, but not general wiring. As a rule of thumb, fixtures are 20% to 30%, and distribution (not included in following costs) is 30% to 70%.

(1) General room lighting; A large proportion of commercial space requires even illumination on the workplace.This can be done a number of ways.

  1. Direct lighting is the most common form of general room lighting.
  2. Semidirect lighting; All systems other than direct ones necessarily imply that the lighting fixtures are in the space, whether pendant-mounted, surface-mounted, or portable. A semidirect system will provide good illumination on horizontal surfaces, with moderate general brightness.
  3. General diffuse lighting; A general diffuse system most typically consists of suspended fixtures, with predominantly translucent surfaces on all sides.Can be incandescent,fluorescent,or HID.
  4. Direct-indirect lighting; A direct-indirect will tend to equally emphasize the upper and lower horizontal planes in a space (i.e.,the ceiling and floor). Typical fixture:same as semidirect.
  5. Semi-indirect lighting; A semi-indirect system will place the emphasis on the ceiling, with some downward or outward-directed light.
  6. Indirect lighting; A fully indirect system will bounce all the light off the ceiling, resulting in a lowcontrast environment with little shadow. Typical fixture:Same as Direct-Indirect.
  7. Accent or specialty lighting; Used for special effects or spot lighting, such as lighting art objects or products on display.


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