ctb assignment

8/8/2019 CTB Assignment

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Construction Technology -B 2010

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Project (A)

A two storey commercial building is proposed for super market and the building is decided to

construct in the heart of the city Kandy, which a steel structural frame work and precast

concrete panels.

Task- 01

1.1, 1.2

Steel has become a universal building product due to its strength, versatility, durability andeconomic value. Among its most popular uses today are standing seam metal roofs.

Standing seam metal roofs are fast becoming the material of choice f or countless structures. Infact, according to the American Iron and Steel Institute, the roofing system has been used innearly 50% of all low-rise commercial, industrial and institutional buildings erected in the lastseveral years. Standing seam metal r oofing can now be seen on virtually every type of building,from shopping centers and schools to churches and libraries. The system currently accounts

for well over one billion square feet.

This acceptance has carried over to the re-roofing market where standing seam roofs have

been used successfully as replacements for built -up and single ply systems.

In retrofit projects where costly tear -offs want to be avoided, a sub -framing system is attachedto the existing roof surface to provide a minimum ¼:12 pitc h for the new metal roof.

Steel Provides Aesthetic Appeal, Long Service Life

The use of metal roofing is growing rapidly because steel offers a variety of benefits. One is its

aesthetic appeal. The standing seam roof is one of the most attractive roofing systems for almost any building. It is available in a wide range of finishes, color and profiles, providing

building owners and architects with extensive design flexibility.

Another of metal roofing¶s benefits is its long service life. As a result of the zinc, aluminum, or aluminum-zinc alloy metallic coating applied to the base st eel, today¶s metal roof panels resistcorrosion and provide a service life of 20 years or more of trouble -free performance,considerably longer than the standard protection for built -up and single ply systems.




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Steel Roof Is Cost Effective, Energy E fficient

Metal roofs are also very cost effective. Standing seam steel roofs pay for themselves from theday they are installed. Their life expectancy is long, they require little or no maintenance, andtheir life cycle costs are low, especially compared to non-metal alternatives in low slopeapplications.

Metal roofs are also energy efficient, especially when used in ³cool roof´ applications. Coolmetal roofs feature heat-deflecting coatings that decrease unwanted heat build -up inside abuilding, thereby reducing cooling loads. Based on research on cool metal roofing, thereflectivity and emissivity of steel roofs have been proven to provide significant savings in

energy consumption.

Environmental Benefits of Steel Are Many

While building owners and archi tects have long recognized steel for its strength, durability andfunctionality, they are now increasingly recognizing another of steel¶s important attributes ± its

environmental benefits.

The recycled content for steel used in metal roofs and walls, for e xample, is at least 25%. Thislevel of recycled content reduces both the cost and environmental impact of making new steel,as it conserves energy and other natural raw materials.

The fact that the recycled content of steel is at least 25% by weight helps earn points in theU.S. Green Building Council¶s Leadership in Environmental and Energy Desgin (LEED)program. Steel¶s recycled content is especially important when it is compared to other materialssuch as concrete, which has a recycled content of only 3 % (fly ash) and even less when theweight of the recycled material is factored in.

Steel Is 100% Recyclable at End of Useful Life

Steel is also 100% recyclable at the end of its long, useful life. In fact, of the metals used inroofs and walls, steel is the most recycled. Easily separated from other materials via magnetic,

steel is reclaimed through a vast collection and processing n etwork.

Every ton of steel recycled saves over 4,000 pounds of raw materials, including 2,500 poundsof iron ore, 1,400 pounds of coal and 120 pounds of limestone. And, according to the EPA,new steel made with recycled material uses as little as 26% of t he amount of energy that wouldbe required to make steel from iron and other materials extracted from nature. In addition, the




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original embodied energy of steel products is amortized as steel is recycled again and againinto new steel products.

Main frame

The frame includes the following components: Inner frames, End walls, Anchor bolts Wind

members on roof and in walls; Generally, the inner frame is a rigid frame made of weldedmembers and columns jointed by means of high -strength bolts (10.9 Class).The joints between

column base plates and foundations are pinned. Joint may be fixed, Extra painting is optional.

Structures are treated using shot -blasting (SA 2.5 degree) and painted with a primer (of grey or

red color).

Secondary frame

The frame is used for supporting wall cladding and roof systems. The secondary frame

comprises a system of grits, purling & eave struts Z- or C-shaped hot deep galvanized cold

formed structural sections and secured to the main frame by bolts (4.6 Class).Th is system

increases frame capability when using together with flange braces. The steel used is of 390

MPa yield strength.

Roofing

The roof system is composed of: Outer steel sheet with Super polyester protective coating.

Waterproofing lay. Insulation of thickness required. Barrier against vapor penetration. Inner

steel sheet - as required. Set of self -tapping screws with heads of the panel -matching color

and all insulating and sealing elements required.

PVC Membrane

PVC membrane is used for covering roof of 15% slope. The PVC membrane comprises a

solid welded homogenous coating made of material strips secured to the base and

overlapped. The PVC membrane is vapor -proof: it lets vapor out but holds water. The PVC

membrane roof consists of: The base coated with vapor insulant. Insulant. Geotextile (when

polystyrene is used in the insulant layer). PVC membrane.

Wall cladding systems

The standard wall cladding system is structurally similar to the SRR 1 roofing system: Outer

steel sheet with super polyester protective coating. Waterproofing lay. Insulation of

thickness required. Barrier against vapor penetration. Inner steel sheet - as required. Set of

self-tapping screws with heads of the panel -matching color and all insulating and sealing

elements required. Sandwich Panels




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Securing system makes it possible to fix panels in two manners: Standard fixing using self -

tapping screws. Concealed fixing which does not require outer layer through drilling.

Accessories and additional elements

STEELAR system contains a complete set of accessories and extra elements:

Roof skylights

Translucent roof and facade panels

Gutters

Smoke exhaust holes

Windows

Doors

Gates

Walkways

Routes for laying inner utilities

If required, the main frame may have built -in tracks for overhead traveling cranes and

mezzanines.

Rigid frame with or without inner columns

Gable roof

Application:Standard projects: warehouses, process shops with ordinary column grids.

Building rigid frame with a multi gabled roof

Application:

Sports facilities, hypermarkets and etc.

Rigid frame for securing on reinforced concrete columns

Application:

It is the optimum for erection of buildings in summer period when use of reinforced concrete

columns is economically effective.

Extensions and buildings wit h a multi gabled roof

Application:

Buildings with specific purpose.

shops, stores and etc.

Buildings with longer spacing between frames of up to 18 m




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In the types above the frame spacing is in -between 4-12 m

Application:

Buildings with specific column spacing

Multi-storeybuiding Application:

Multi-tier parking facilities and shopping centers.

y Precast Concrete work in the construction

Precast concrete consists of concrete (a mixture of cement, water, aggregates and admixtures)

that is cast into a specific shape at a location other than its in-service position. The concrete is

placed into a form, typically wood or steel, andcured before being stripped from the form,

usually the following day. These components are then transported to the construction site for

erection into place.

Precast concrete components are reinforced with either conventional reinforcing bars, strands

with high tensile strength, or a combination of both. The strands are pre-tensioned in the form

before the concrete is poured. Once the concrete has cured to a specific strength, the strandsare cut (de-tensioned). As the strands, having bonded to the concrete, attempt to regain their

original un-tensioned length, they bond to the concrete and apply a compressive force. This

³pre-compression´ increases load-carrying capacity to the components and helps control

cracking to specified limits allowed by building codes.

Precast components are used in various applications and projects of all types.

y Beams

Beams are typically considered structural components and are made in one of three key

shapes:

1. Rectangular

2. Inverted Tee Beams

3. L Beams

Beams are horizontal components that su pport deck members like double tees, hollow-core,

and solid slabs, and sometimes other beams. They can be reinforced with either pre -stressing

strand or conventional reinforcing bars. This will depend on the spans, loading conditions, and

the producer¶s preferred production methods.

Columns

Columns are typically used to support beams and spandrels in applications such as parking

structures and total-precast concrete structural systems of all types. They typically are

designed as multilevel components rangin g from a single story to six levels or more.




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Mullions

Mullions are thin, often -decorative pieces that fill open space in a building facade. They are

often isolated elements forming a long vertical line, requiring them to be cast perfectly straight

to avoid any visual deformities. To some degree, these variations can be handled by precast

concrete connections with adjustability.

Piles

Precast, pre-stressed concrete pilings are often the preferred choice for permanent , durable,

and economical foundations, espec ially in marine or bridge environments, due to their excellent

adaptability and resistance to corrosion.

Piles can be spliced together to create longer piles. They are used primarily where longer piles

are required but transportation needs make the longer lengths more difficult or costly to handle

due to escort needs and the need for specialized rigs.

Shear Walls

Shear walls act as vertical cantilever beams, transferring lateral forces acting parallel to the

face of the wall from the superstructure to the f oundation. Typically, there are two shear walls

oriented to resist lateral loads along each principal axis of the building. They should be

designed as load bearing panels.

Solid Slabs

Solid slabs are used as structural deck components similar to hollow -core slabs. They can be

made in a long-line pre-tensioning facility and reinforced with pre -stressing strand or cast in

individual forms with either pre -stressing strand or conventional reinforcing bars.

They are typically cast in the same position as used i n the structure.

y Raker Beams-Raker beams are angled, notched beams that support stadium riser

units. They are used universally in outdoor stadiums and arenas and in many indoor

arenas and performing -arts theaters.

y Stadium Risers -Stadium risers are used to support seating in stadiums, arenas,

theaters, and other types of grandstands.

Typically, they are made as single, double, or triple risers with heights cast to satisfy site lines

in the venue. Specifying single, double, or triple risers will depend on the layout and may be

dictated by weights and crane access during construction

y

Stairs-Precast concrete stairs are used in any application where a stair tower or individualsteps are required. These modules c an provide fast erection and durable access in buildings

or parking structures.

Wall Panels - Wall panels can be strictly architectural, strictly structural, or a combination of

both. They can be placed in either a horizontal position, as in a multifamily housing application

or in a vertical position, as in the exterior of a warehouse. Wall panels can be load bearing and

support floor and roof components or they can be no load bearing to complete a façade.




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Precast Concrete Systems

The design of precast, pre-stressed concrete structures depends on the integration of the

structural system as a whole, the connections, and the individual components. Each aspect

must consider the others as well as the functional requirements imposed by the building use. It

is essential that design loads follow a load path from their point of origin to the final support or

foundation.

Although not always required by code, it is desirable to design the members and their

connections to achieve a ductile, rather than a brittle, fail ure mode. In addition to resisting

gravity loads, a principal consideration in building design is the lateral force -resisting system.

There are a variety of precast concrete designs that can be used to achieve these goals

economically and effectively.

Structural-Steel Framing Supporting Architectural

Precast CONCRETE Cladding

Precast concrete panels should follow the steel frame as erected, because the allowable

tolerances for steel-frame structures make it impractical to maintain precast concrete panels i n

a true vertical plane in tall structures. The adjustments that would be required to make the

connections practical are not economically feasible.

elevator-column erection tolerances for steel columns used in the building façade that will

receive the precast concrete panels A structural-steel-frame building presents different erection

and connection considerations from a concrete -frame building.

For example, structural -steel beams, being relatively weak in torsion when compared to

concrete, generally requ ire the load to be applied directly over the web or that the connection

be capable of supporting the induced torsion. This in turn places a greater structural

requirement on the connection and creates difficulties during erection if any rolling behavior

occurs in the steel beam.

Earthquake Resistance

Precast concrete can be designed to resist seismic events.

Earthquakes generate horizontal and vertical ground movement.

When the seismic waves pass beneath a structure, the foundation tends to move with

the ground, while the superstructure remains in position.

The lag between foundation and superstructure movement causes distortions and

develops forces in the structure.

As the ground moves, distortions and forces are produced throughout the height of the

structure, varying with the ground acceleration and the resonance of the building.

The key reason designers have gravitated toward precast concrete components is because

they can span long distances between attachments to the main structure. Design methods and

details have been developed to accommodate these applications in seismic areas.




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1.3

BUILDING AND SITE DESIGN

The faster the fire service can respond, enter ,locate the incident, and safety operate in a

building, the sooner they can mitigate an incident in a safe manner for themselves as well as

occupants.

Fire Apparatus access.

Properly fire Apparatus can be critical at a fire scene. In particular, placing aerial Apparatus is

critical for positioning of the aerial ladder or elevating platform, which is mounted on top of

these vehicles. Pumper Apparatus also need to get close enou gh to the building to facilitate

hose line use. The location of other specialized Apparatus, or small vehicles, such as chief¶s

cars or ambulances, should only be of particular concern to the designer of unusual facilities.

For instance, a sports arena may need to be designed for entry of ambulances but not fire

Apparatus.

There are many considerations for both public roads and fire lanes: clear width, clear height,length, turn radius, arrangement, distance from the building, and paving materials.

Extent of Access

Minimum building access for fire Apparatus is a function of the access road reaching to within a

certain distance of all portions of the building¶s first floor exterior walls.

Perimeter Access

The options available for attacking a fire increase as more of a building¶s perimeter becomes

accessible to fire Apparatus.

Clear width

The basic clear width requirement for Apparatus access in the IFC and NFPA 1 is 20feet.

NFPA 1141 calls for one way fire lanes that are 16 feet wide; however, this applies t o roads

that do not about buildings. A clear width of 20ft will allow most aerial Apparatus to extend the

outriggers necessary to support the aerial ladder or elevating platform while in operation.

However, some recently manufactured aerial apparatus require 24 ft of clear width for outrigger

extension.

Lanes wide enough for apparatus to pass one another will facilitative developing and

expanding operations. NFPA 1141contains a 24 ±foot clear width requirement for two -way fire

lanes. Appendix D of the IBC calls for a 26 ±foot clear width at fire hydrant locations, extending

for distance of 20ft in both directions. As well as a 26- foot width in the vicinity of buildings that

are 30feet or more in height (for aerial operations.)Rolled or rounded curbs adjacent to properly

designed sidewalks can effectively increase access width. These allow apparatus to easily

negotiate curbs.




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Building proximity

In areas with aerial apparatus that may respond to an emergency, the road or fire lane should

be positioned at a distance from the building that will accommodate aerial ladder operation.

Access too close or too far from the building will limit aerial ladder use. Where a fire lane is

parallel to a building that is more than 30ft high.

Loads ± All access roads or lanes should be built to withstand the loads presented by modern,

heavy fire apparatus as well as potential weather conditions. Paved surface, bridges, and other

elevated surfaces (such as piers or boardwalks) should be designed to handle the weight of a ll

apparatus that may use them. The IFC Appendix D has a load design requirements of 75000

pounds.

Materials ± All weather paved access s the best surface some jurisdictions permit the use of

paved blocks or subsurface construction for fire lanes. These permit an area to be partially or

fully landscaped, while being strong enough to allow fire apparatus to negotiate the area.

Manual gates cause inherent delays because personnel must dismount to unlock them or cut

through chains. However, they can also hel p keep the fire access lane clear by preventing

vehicle parking.

Fire Hydrants

Optimal positioning, spacing, location, and marking of fire hydrants can aid the fire service

during emergency operations. Public fire hydrants are often under the purview of a local water

authority, standards for fire flow and other criteria.

Spacing ± Maximum distance between hydrants differs greatly, depending on various local

standards.

Location ± Pumpers may utilize hydrants in different ways. If the fire is close enough, apumper can be positioned at a hydrant and use a large diameter suction hose.

Marking ± A number of methods are used to enable firefighters to rapidly identify hydrant

locations. The color used for hydrants should contrast as much as possible with the

predominating surroundings. Some localities place reflective tape around the hydrant body .

Other jurisdictions mount reflectors (usually blue) in the roadway in front of each hydrant:

however, in cold weather climates these refle ctors are often obstructed by snow. The best way

to identify hydrants in areas subject to snowy weather is a locator pole which is visible above

the highest expected snowfall. These are reflective or contrasting in color, and some have a

flag, sign, or reflector mounted on top.

Firefighter Access

Once firefighter have arrived and positioned their apparatus, they must go to work. Some

factors affecting their efficiency include: the distance and terrain between the apparatus access

and the building: how easily they can enter the building: the buildin g¶s interior layout and

vertical access (stairs / elevators/ roof access): and, how quickly firefighters can locate fire

protection features and utilities.




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Steel is an alloy consisting mostly of iron, with a carbon content between 0.2% and 2.1% by

weight, depending on the grade. Carbon is the most cost -effective alloying material for iron, but

various other alloying elements are used such as manganese, chromium, vanadium, and

tungsten and etc.

Compressive stress

Compressive stress is the stress that, when applied, acts towards the center of that material.

When a material is subjected to compressive stress, then this material is under compression.

Usually, compressive stress applied to bars, columns, etc. leads to shortening.

Rebar

A rebar, or reinforcing bar, is a common steel bar, and is commonly used in reinforced concrete

and reinforced masonry structures. It is usually formed from carbon steel, and is given ridges

for better mechanical anchoring into the concrete.

Reinforced concrete

Reinforced concrete is concrete in which steel reinforcement bars , plates or fibers have been

incorporated to strengthen a material that would otherwise be brittle.

Pre-stressing can be accomplished in three ways:

1. Pre-tensioned concrete ,

2. Bonded post-tensioned concrete.

3. Unbounded post-tensioned concrete .

Pre-tensioned concrete

Pre-tensioned concrete is cast around already tensioned tendons. This method produces a

good bond between the ten don and concrete, which both protects the tendon from corrosion

and allows for direct transfer of tension. The cured concrete adheres and bonds to the bars and

when the tension is released it is transferred to the concrete as compression by static friction .

However, it requires stout anchoring points between which the tendon is to be stretched and

the tendons are usually in a straight line. Thus, most pre -tensioned concrete elements are

prefabricated in a factory and must be transported to the construction site, which limits their

size. Pre-tensioned elements lintels, floor slabs, beams or foundation piles.

Friction - Friction is the force resisting the relative lateral motion of solid surfaces, fluid layers,

or material elements in contact.

Prefabrication

Prefabrication is the practice of assembling components of a structure in a factory or other

manufacturing site, and transporting complete assemblies or sub -assemblies to the

construction site where the structure is to be located.

Bonded Flat Slab System - Supply of flat slab post -tensioning system using both 12.9mm

and 15.7mm strand Installation of f lat slab post-tensioning system.




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Bonded post-tensioned concrete

Bonded post-tensioned concrete is the descriptive term for a method of applying compression

after pouring concrete and the curing process (in situ). The concrete is cast around plastic,

steel or aluminum curved duct, to follow the area where otherwise tens ion would occur in the

concrete element. A set of tendons are fished through the duct and the concrete is poured.

Once the concrete has hardened, the tendons are tensioned by hydraulic jacks that react

against the concrete member itself. When the tendons have stretched sufficiently, according to

the design specifications (Hooke s law), they are wedged in position and maintain tension after

the jacks are removed, transferring pressure to the concrete. The duct is then grouted to

protect the tendons from corrosion.

This method is commonly used to create monolithic slabs for house construction in locations

where expansive soils (such as adobe clay) create problems for the typical perimeter

foundation. All stresses from seasonal expansion and contraction of the underlying soil are

taken into the entire tensioned slab, which supports the building without significant flexure.

Post-tensioning is also used in the construction of various bridges, both after concrete is cured

after support by false work and by the assembly of prefabricated sections, as in the segmental

bridge .The advantages of this system over unbounded post-tensioning are: Large reduction in

traditional reinforcement requirements as tendons cannot distress in accidents.

Tendons can be easily weaved allowing a more efficient design approach. Higher ultimate

strength due to bond generated between the strand and concrete. No long term issues with

maintaining the integrity of the anchor/dead end.

Hooke's law

In mechanics, and physics, Hookes law of elasticity is an approximation that states that the

extension of a spring is in direct proportion with the load added to it as long as this load does

not exceed the elastic limit.

Wedge (mechanics)

A wedge is a triangular shaped tool, a compound and porta ble inclined plane, and one of the

six classical simple machines. It can be used to separate two objects or portions of an object,

lift an object, or hold an object in place. It functions by converting a force applied to its blunt

end into...

Grout

Grout is a construction material used to embed rebars in masonry walls, connect sections of pre-cast concrete, fill voids, and seal joints. Grout is generally composed of a mixture of water,

cement, sand and sometimes fine gravel.

Corrosion

Corrosion is the dis integration of a material into its constituent atoms due to chemical reactions

with its surroundings. In the most common use of the word, this means a loss of electrons of

metals reacting with water and oxygen. Weakening of iron due to oxidation of the iron.




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False work

False-work consists of temporary structures used in construction to support spanning or arched

structures in order to hold the component in place until its construction is sufficiently advanced

to support itself.

Segmental bridge

As its name implies, a segmental bridge is a bridge built in short sections , i.e., one piece at a

time, as opposed to traditional methods that build a bridge in very large sections. Un -bonded

flat slab construction , Un-bonded anchors in banded layout

Un-bonded Mono-strand System

Supply of mono strand system using 15.7mm and 15.2mm Dyform/Compact strand Installation

of mono strand post tensioning system Un -bonded live anchors installed Sloping un -bonded

post-tensioned on slab edge form -work, roof awaiting concrete pour

Un-bonded post-tensioned concrete

Un-bonded post-tensioned concrete differs from bonded post -tensioning by providing each

individual cable permanent freedom of movement relative to the concrete. To achieve this,

each individual tendon is coat ed with a grease (generally lithium based) and covered by a

plastic sheathing formed in an extrusion process. The transfer of tension to the concrete is

achieved by the steel cable acting against steel anchors embedded in the perimeter of the

slab.

The main disadvantage over bonded post -tensioning is the fact that a cable can destress itself

and burst out of the slab if damaged (such as during repair on the slab). The advantages of this

system over bonded post-tensioning are: The ability to individually ad just cables based on poor

field conditions (For example: shifting a group of 4 cables around an opening by placing 2 toeither side). The procedure of post -stress grouting is eliminated. The ability to de -stress the

tendons before attempting repair work.

Extrusion - Extrusion is a process used to create objects of a fixed cross -sectional profile. A

material is pushed or drawn through a die of the desired cross -section.

Lithium - Lithium is a soft, silver -white metal that belongs to the alkali metal group of

chemical elements. It is represented by the symbol Li, and it has the atomic number three.

Under standard conditions it is the lightest metal and the least dense solid element.

Applications

Pre-stressed concrete is the predominating material for floors in high-rise buildings and

concrete chambers in nuclear reactors.Un -bonded post -tensioning tendons are commonly used

in parking garages as barrier cable. Also, due to its ability to be stressed and then de -stressed,

it can be used to temporarily repair a damaged building by holding up a damaged wall or floor

until permanent repairs can be made.




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Project (B)

Task -02

2.1)

Water is the most important factor for survival of man and animals. A person can do withoutfood for five weeks or more, but without water he can survive for only a few days.

y Your water and your health gives a listing of the ten basic kinds of water,

1. Hard water. 6. Soft water.

2. Boiled water. 7. Filtered water.

3. Raw water. 8. Reverse osmosis.

4. Rain water. 9. De- ionized water.

5. Snow water. 10. Distilled water.

First I would like to explain bit of think about water such as,

y Per capital demand as per IS ± 1172- 1963

Purpose Requirements in litters per head per day

Domestic 185

Public use 15

Firefighting 15

Industrial use 50

Wastage & Losses 50

Total 270Lits/H/D

Water supply in buildings

Many administrative authorities controlling water supply have their own set of bye - laws, rule

and regulation. While Laying pipe lines or plumbing systems these bye-laws should be strictly

confirmed. For intermittent supplies a minimum storage of half days supply is needed for

overhead tanks. IS-2065-1072 deals with water supply of building and covers general

requirements and regulations for water supply, Plumbing, connected to public water supply,

inspection and maintained water fittings and appliances.




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The Boiler

Boiler with the correct rating must be selected from manufacturer catalogues where boiler

rating = A + B

Where A- Heating capacity of calorifier

B- Safety margin (Normally 10 ± 20 % )

Design Pipe scheme and size pipe

The maximum volume flow through connection pipe to fittings and other equipment is

determined by the maximum demand of each consumer of fitting. The maximum volume flow

through main pipes is determined by the maximum demands of the fi tting and statistic demand

based on the number and types of fittings and equipment supplied. A domestic hot-water

system supplies the taps in a house ort a building with hot water.




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2.2). Drainage

Proper drainage is important to ensure a high quality long lived pavement; moisture

accumulation in any pavement structural layer can cause problems. Moisture in the sub-grade

and aggregate base layer can weaken these materials by increasing pore pressure and

reducing the materials resistance to shear. Additionally, some soils expand when moist,

causing differential heaving. Moisture in the HM A layers can cause stripping because it,

instead of the asphalt binder, will adhere to aggregate particles.

Storm Drain Pipe Awaits Installation in a Road Reconstruction Project

Moisture sources are typically rainwater, runoff and high groundwater. Hese sources are

prevented from entering the pavement structure or accumulating in the sub -grade through

surface drainage and subsurface drainage. Usually, it is more cost effective and less risky to

prevent moisture entry and accumulation using surface drainage than to effect moisture

removal using subsurface drainage.

Surface Drainage

Surface drainage is concerned wi th removing all water that is present on the pavement surface,

shoulder surface or any other surface from which it may flow onto the pavement. If not

systematically removed, this water can accumulate underneath and weaken the pavement

structure. There are three primary means used to prevent water infiltration and accumulation:

Impermeable HM A.

HM A tends to be impermeable below about 8 percent air voids, therefore proper compaction

practices should be followed to ensure an impermeable pavement. Also, minor cracks in the

HM A should be promptly sealed.

Slope.

The pavement section should be sloped to allow rainwater to sheet flow quickly to the edge

where it is typically collected in a curb and gutter system or a roadside ditch. A generally

accepted standard is a 2 percent cross slope.

Grade.

The curb and gutter or roadside ditch must be properly graded to allow flow to central collection

points such as catch basins or detention ponds. A generally accepted standard is a grade of

0.5 percent or more although lesser grades have been used effectively.

Subsurface Drainage

Subsurface drainage is concerned with removing water that percolates through or is contained

in the underlying sub-grade. This water, typically the result of a high water table or

exceptionally wet weather, can accumulate under the pavement structure by two chief means:




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LIGHT SWITCHES

Most room lights are controlled by wall mounted toggle switches (although alternatively touch

sensitive or rotary light dimmers can be fitted), The cable normally runs down the wall within

conduit within the plaster. A flush fitting wall box is sunk into the wall to take the switch, or

alternatively a surface mounted box is fitted. Multi - switch units enable more than one light to

be controlled from one position.

In bathrooms and shower rooms, the switch must be a pull string type. These switches can

also be used when new lights are being installed - they can easily be screwed under a ceiling




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joist with minimal disturbance to the decorations. There is a tendency to feel that pull switches

are only suitable for bathrooms etc, however this limits the opp ortunities and should be

avoided. When a new light is to be positioned over a work surface or even an external light

fitted, there is no reason why a pull switch should not be mounted in any convenient position.

2 WIRING METHODS

There are 2 basic wiring methods of wiring lights- by ceiling rose and by junction box. Systems

using the ceiling roses make all the connections at the ceiling rose. While this removes the

need for one junction box per lamp, it is often more awkward for the average diy¶er.

RING CIRCUIT

The ordinary wall sockets around the house are normally connected to a ring circuit (also

referred to as a ring main). The ring circuit of a domestic property supplies the socket outlets

and fixed appliances in the premises.

The µring¶ is formed by the cable going from the consumer unit to the first socket, than on to the

second socket and than the next socket etc. Unit the cable returns to the consumer unit. Thismeans (in simple terms) that every socket on the ring circuit consist of a red (live) wire, a block

( neutral) wire and a bars copper earth wire, all three being enclosed by an outer PVC

sheathing. The cable used in domestic ring circuits is either 2.5 sq mm or 4.0sq mm twis core

and earth, these are rated (in free air) at 24am p or 32 amps respectively. Each ring circuit is

protected by a 32amp fuse or trip fitted in the consumer unit. Modern installations incorporate a

residual current device (RCD) before the consumer unit which trips the whole system off if a

fault is detected.

A ring circuit is considered to be rated at 30amps (7200 walls). A ring may serve up to 100m sq

of floor area and, in theory, may have any number of sockets outlets or fused connection units

connected to it. Wire each socket outlet is normally rated at 1 3 amps, as a µrule of thumb¶ they

are limited to under twenty outlet; it is unlikely that the variety of domestic appliances being

used at any one time will exceed 30amps. The length of cable used in a ring circuit is limited to

50 m for circuits protected by an MCB. The sockets are normally mounted flush with the wall

although surface mounted boxes are often easier to fit when sockets are added to the circuit. It

is advisable to have two ring circuits in all premises, in multi floor houses, one for each fl oor.

RING CIRCUIT FUSED OUTLET UNIS

Where connection to a fixed appliance is required, a fused outlet unit may be fitted to the wall

(rather then a plug socket) and connected into the ring main. These u\outlets require the

correct fuse rating for the appliance and are connected to the appliance by a cable or flex. The

outlet may be switched or unswitched and may be fitted with an indicator light to show whenthe supply is connected. Where a flex is taken to heater of any sort (e.g. night store heater) the

flex must be of a special µhigh temperature¶ type suitable for the elevated temperatures

encountered.




25

HIGH POWER CIRCUITS

Within domestic premises, there may be a number of high wattage applia nces, the most

common being an electric cooker, immersion heater and electric shower. Each of these

appliances should be connected to the consumer unit using a dedicated fuse/trip and cable

run. The installation instructions for the appliance should detail the wattage of the appliance

(which will also normally be shown somewhere on the appliance), the amperage of the fuse/trip

and size of cable required. Any switches on these circuits must also be of a suitable current

rating.

POWER FOR OUT OF DOORS

When power is required for the shed, patio, garden pond or other out of doors purpose, a

separate from the consumer unit should be used. Where a residual current device (RCD) is not

already fitted before the consumer unit, one should be installed. The residual current device

will switch off the electricity almost instantaneously if a fault develops in the circuit.

Waterproof sockets must be used where an outside socket is required, an internal control

switch is also recommended so that the outside socket can be isolated if necessary. There are

a number of alternatives to using mains electricity in the garden lights and appliances are

available to reduce the risk of using electricity out of doors.

ELECTRIC POWER CABLES

The standard UK domestic electricity supply is 230 volts AC. Solid core cables should never be

reused ± although they can be bent into shape. They are not designed to be flexed and

repeated movement can weaken the cores causing then to become weak, overheat or fail.

Twin core and earth (general inte rnal power cables). Consists of two insulated solid cores with

a bare copper earth conductor between the inner cores and an overall PVC sheath. The colors

being;

Per march 200 Post march 200

Live Red BrownNeutral Block BlueEarth Green and yellow

Core size

mm

2

Current (A) Wattage (kW) at

240v

Typical applications

1.0 14 3.25 Lighting

1.5 18 4.25 Lighting2.5 24 5.75 Power circuit4.0 32 7.75 Power circuit shower

6.0 40 9.75 Shower , cooker 10 53 12.9 cooker




27

Building automation systems, which are present in more than half of all buildings i n the U.S.

larger than 100,000 square feet, save between 5 and 15 percent of overall building energy

consumption. Generally, BASs are most cost -effective in buildings that consume lots of energy,

such as data centers and hospitals. Older or poorly maintain ed buildings can also benefit

greatly from a BAS retrofit, sometimes yielding savings of over 30 percent.

In addition to saving energy, BASs can reduce overall building maintenance costs by

identifying operational problems early and often. For example, BAS s can collect data from

multiple zones around a building and display it on the system¶s front -end computer. This

enables the building operator to monitor and access the data to diagnose an operational

problem rather than deploying a maintenance crew to sea rch for it.

Unfortunately, many building automation systems save less energy than they could if set up

optimally. In one detailed study of 11 buildings in New England with BASs, five of the buildings

were found to be underachievers, producing less than 55 percent of expected savings. One

site produced no savings at all.

To improve the likelihood that your BAS will achieve the expected benefits, you should take

advantage of advanced control strategies that use the computer -processing power of a BAS

and adopt a comprehensive approach to quality control known as commissioning. This process

is now required for some buildings, such as public institutions and buildings certified by the

U.S. Green Building Council¶s LEED (Leadership in Energy and Environmental Desi gn)

program. Commissioning includes reviews and inspections throughout the design and

construction process as well as rigorous performance tests that move the system through its

sequences of operation before the building is occupied. Commissioning conclude s when the

building¶s systems are working as planned and the operations team is thoroughly trained in

using all of the system¶s features.

It¶s also important to ensure that a BAS continues to work properly over time.

Recommissioning²in which building operators use trending and energy consumption data to

periodically verify, document, and improve a building¶s operation ²can be conducted

throughout the life of the building.




29

Hazards to the Fire service

During a fire, any building may become inherently unsafe for occupants and fire service

personnel. However, some building construction features present unique or unexpected

hazards.

Lightweight Construction

Trusses are widely used in construction to span wide areas without the need for vertical

supports, reducing both material and construction costs. However, trusses often fail suddenly

and totally during fires. Both wood and metal trusses are made of interdependent members

who all fail if one member fails.

Shaft- Ways

Vertical shafts within buildings sometimes have exterior openings accessible to fire fighter. Any

such doors or windows should be marked ³SHAFTWAY´ on the exterior with at least 6 Inch

high lettering as required by the IFC and NFPA1.

Skylights

Without special precautions, roof - mounted skylights obscured by heavy smoke or snow may

collapse under the weight of a firefighter. Skylights should be designed to bear the same

weight loads as the roof. The same applies to covering over unused skylights. If this is not

practical, mount barriers around skylights to prevent firefighter from inadvertently stepping on

them.

Some fire security equipments

1. Fire Break Glass (BGA)

2. Fire Indicator Panel (F.I.P)3. Fire Doors

4. Smoke and Thermal Fire Detectors.

5. Portable Fire Extinguishers.

There are several type s of fire extinguishers.

1. Water.

2. Foam.

3. Carbon Dioxide.

4. Dry- Chemical.

5. Wet chemical.




30

P E )

3.1)

Def inition:

ine of communication travelled way) using a stabili ed base other than rails or air str ips open

to pub lic traffic, pr imar ily f or the use of road motor vehicles running on their own wheels.Context:

Included are br idges, tunnels, suppor ting structures, junctions, crossings and interchanges. oll

roads are also included. Excluded are dedicated cycle paths.

A road is an identifiable route, way or path between places. oads are typically smoothed,

paved, or otherwise prepared to allow easy travel; Road surface Br itish English) or pavement

Amer ican English) is the durable sur f ace mater ial laid down on an area intended to sustain traffic veh icular or f oot traffic). Such sur f aces are f requently marked to guide traffic. he most

common modern paving methods are asphalt and concrete. In the past, br ick was extensively

used, as was metalling. oday, permeable paving methods are beginning to be used more f or low-impact roadways and walkways.

The most common modern paving methods are asphalt and concrete.

Histor ically, pavements have been divided into two broad categor ies, r igidand flexible. hese

classical definitions, in some cases, are an over -simplification. However , the terms r igid and

flexible provide a good descr iption of ho w the pavements react to loads and the environment.

Sub-bases and Sub-grades

A reasonably unif orm sub-grade or sub-base, with no abrupt changes in suppor t, is ideal f or

an y concrete pavement. Most native soils are not too unif orm and thus require some

improvement or additiona l layers to compensate.A sub-base is a thin layer of mater ial placed

on top of the prepared sub-grade.Sub-bases provide unif orm suppor t to the pavement and a

stable platf orm f or construction equipment. Sub-ba ses also help prevent movement of sub-

grade soils at transverse pavement joints in roads sub ject to a large volume of truck traffic.

Sub-bases may be gravel, stone, cement-modified soil, asphalt, or econocrete low-strength

concrete). he sub-base and base courses may be constructed f rom more than one individual

layer of the specified mater ial, but f or our purposes, we will consider each layer as being a

single entity. Sometimes, , levels permitting, an existing bitmac or concrete sur f ace can be

over laid with a new sur f ace course. his is acceptable provided that the new sur f acing is

proper ly bonded to the old sur f ace.




31

Construction Method

Mark out the site. It is assumed that the sur f acing is to be flush i.e. level, with the existing

ground. It is a good idea to excavate wider than the planned width, allowing an extra -

450mm at the edges makes handling much easier , especially if Krebs are to be used. In most

cases, a well-laid tar macadam sur f ace is impermeable to water , and should be constructed in

such a manner that sur f ace water will be directed to ad jacent open ground, a gully or similar

drainage point. Bear in mind that pr ivate dr iveways are not permitted to drain onto a public

highway or directly into the sewer system.

Excavation

he sur f ace needs to be dug off to a depth of at lea st 5mm. he depth of dig can be roughly

calculated as.... sur f ace course binder course sub-base)Conditions may vary with

countr ies and local practice based on their exper ience. All weeds and othe r unwanted organic

matter , along with topsoil must be removed and any soft spots excavated and filled with

compacted sub-base mater ial. If the area is troubled with weeds, it should be treated the

excavated sub-grade with a general weed killer such as Sodium Chlorate, but it is unlikely any

weed will be able to penetrate the upper layers.

A eo-membrane can be used if deep-rooted, pernicious weeds are a problem, of if there is

an y concern regarding the competence of the sub-grade. o edging/kerb crumbling edges

Edgings or kerbs M S be used on f ree edges, i.e. those par ts of the per imeter of the sur f aced

area not bounded by walls or other solid structures that will act as a retainer f or the bitmac.

his is to prevent the bitmac crumbling at the edges, as shown in the photograph opposite.

Br ick edgings, plain or decorative edging Krebs, or sets laid lengthways are all suitable, and

should be constructed at this stage.

Sub-base

his is essential if the pavement is to last longer than a couple of years. o not emp loy any

con tractor who tells you that a sub-base is not required, unless there is a suitable existing sub-

base or base layer . he sub-base should be a minimum 00mm thick.




32

Binder course

This is a load-bearing, strengthening layer of the pavement and should be at least 40mm,

preferably 50mm thick.The material used as a binder course is chunkier than a wearing

course, usually comprising 20mm or 28mm aggregate in a bitumen binder, known as Dense

Bitumen Macadam (DBM). On public highways and other heavier -use projects, the binder

course may be underlain by a base layer. For binder course 50 -80mm thick, use 20mm

material (DBM). For binder course 70-150mm thick, use 28mm material (DBM)

Surface course

This is the top layer of the bitmac pavement, the layer that is seen and trafficked. It needs to be

fairly regular to provide a smooth ride for wheeled vehicles, although this is much more

important on higher speed pavements than on residential driveways. A macadam surface

course should consist of a small, hard aggregate, usually 6mm or 10mm, in a bitumen or

asphalt binder.

Alternatively, an asphalt may be used; this material is also known as a sand carpet or asphalt

carpet, and is prepared in a batch plan t to a specified recipe, consisting of selected sands and

grits mixed into an asphalt matrix, with coated chippings sprinkled over the surface and rolled

into the asphalt as part of the compaction process. Again, it may be machine or hand laid,

depending on area and access.

The wearing course should be at least 20 -25mm thick when rolled, and should not deviate from

the correct level by more than 6mm. There should be no roller marks in the finished surface.

Some road Construction Materials




33

Road Construction Equipments

Some Road Safety signals




34

3.2) Surface Drainage

Surface drainage is concerned with removing all water that is present on the pavement surface,

shoulder surface or any other surface from which it may flow onto the pavement. If not

systematically removed, this water can accumulate underneath and weaken the pavement

structure. There are three primary means used to prevent water infiltration and accumulation:

Impermeable HM A. HM A tends to be impermeable below about 8 percent air voids, therefore

proper compaction practices should be followed to ensure an impermeable pavement. Also,

minor cracks in the HM A should be promptly sealed.

Slope. The pavement section should be sloped to allow rainwater to sheet flow quickly to the

edge where it is typically collected in a curb and gutter system or a roadside ditch. A generally

accepted standard is a 2 percent cross slope.

Grade. The curb and gutter or roadside ditch must be properly graded to allow flow to central

collection points such as catch basins or detention ponds. A generally accepted standard is a

grade of 0.5 percent or more although lesser grades have been used effectively.

Subsurface Drainage

Subsurface drainage is concerned with removing water that percolates through or is contained

in the underlying subgrade. This water, typically the result of a hig h water table or

exceptionally wet weather, can accumulate under the pavement structure by two chief means:

Gravity flow . Water from surrounding areas can be absorbed by the soil then flow by gravity to

areas underneath the pavement structure. In pavement with high air voids (above 8 ± 9

percent), water can percolate down through the pavement structure itself.

Capillary rise. Capillary rise is the rise in a liquid above the level of zero pressure due to a net

upward force produced by the attraction of the water molecules to a solid surface (e.g., soil).

Capillary rise can be substantial, up to 20 ft. or more. In general, the smaller the soil grain size,

the greater the potential for capillary rise. Often, capillary rise is a problem in areas of high

groundwater tables.

Most pavements have performed adequately without considering these effects. However, HM A

pavements can fail because of subgrade support deterioration as a result of excessive

moisture or other water-related problems. These issues can be addressed in two manners:

1. Minimize water infiltration into the pavement structure . In most cases, the accumulated water

in the underlying subgrade that causes the damage comes from surface infiltration. Thisinfiltration can be minimized by providing proper roadside drainage and minimizing air voids

within the HM A.

2. Provide subsurface drainage . This needs to be done judiciously, because it may be somewhat

akin to treating the symptom rather than the problem. Subsurface drainage consists of three

basic elements A permeable base to provide for rapid removal of water which enters the

pavement structure. Based on recent research from California, permeable base layers ma y

strip and become clogged with fines thus weakening the overall pavement structure. A method

of conveying the removed water away from the pavement s tructure.




35

3.3)

What Retaining Walls Do?

Retaining walls provide lateral support to vertical slopes of soil. They retain soil which

would otherwise collapse into a more natural shape. The retained soil is sometimesreferred to as backfill.Retaining walls can be constructed of many different materials and

with a variety of

Various types of retaining walls

Gravity walls depend on the weight of their mass (stone, concrete or other heavy material)

to resist pressures from behind and will often have a slight batter setback, to improve

stability by leaning back into the retained soil. For short landscaping wal ls, they are often

made from mortarless stone or segmental concrete units (masonry units)

Dry-stacked gravity walls are somewhat flexible and do not require a rigid footing in frost

areas.Prior to the introduction of modern reinforced -soil gravity walls, cantilevered walls

were the most common type of taller retaining wall. Cantilevered walls are made from a

relatively thin stem of steel -reinforced, cast-in-place concrete or mortared masonry (often in

the shape of an inverted T).

These walls cantilever loads (like a beam ) to a large, structural footing, converting

horizontal pressures from behind the wall to vertical pressures on the ground below.

Sometimes cantilevered walls are butressed on the front, or include a counterfort on the

back, to improve their strength resisting high loads. Buttresses are short wing walls at rightangles to the main trend of the wall. These walls require rigid concrete footings below

seasonal frost depth. This type of wall uses much less material than a traditional gravity

wall.

ctb assignment

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