Cladding can be defined as a protective or insulating layer fixed to the exterior of the edifice or any other construction. The aims of cladding system to be built are:
To supply enclosure.
The facing was made to supply enclosure to the edifice which will give the necessary protection against the conditions and external alterations.
Speed of dry building.
The use of off-site prefabrication for the facing can supply a desiccant and faster building.
It imposes minimum extra dead burden.
The facing is normally made from a lightweight stuff and therefore the extra burden impose on the edifice is minimal.
It enhances architectural construct and affect the visual aspect of the edifice.
The facing is made from a different type of stuffs. So, each of the stuff used may squeeze out the visual aspect of the edifice harmonizing to the construct and map of the edifice that the designer wants to plan.
It can command internal environment.
The facing system can command the internal environment of the edifice such as commanding light perforating into the edifice, commanding the radiation and conductivity of heat from the Sun, and many others.
To accomplish the aims, the facing system should obey some of the functional demands. The primary maps of cladding system is to divide the indoor environment of a edifice from the out-of-doorss in such a manner that the out-of-doorss environment will non impacting the indoors and the indoor environment can be maintained at degrees suited for the intended usage. The other functional demands of the facing system are as follows:
The facing system should hold a good strength and stableness.
The facing system must hold equal strength to back up its ain weight between the points of support or ingredients to the structural frame whereas the sufficient stableness is needed to against the sidelong air current force per unit area exposed to the edifice. Both of these characteristics are required in the facing system to let the differential motion between itself ; in footings of stuff enlargement and contraction, between the structural frame or the differential motion in other next edifice component.
The facing system should hold exclusion of air current and rain.
To carry through these standards, a common pattern is to build a solid facing system with an outer foliage as a rain screen and interior foliage as dielectric. Therefore, the stuffs used to seal articulations are required to be resilient plenty to suit motion and resist conditions impairment. To prolong the force per unit area and suctions by the air current, the facing must be adequately strong and stiff. The air current waies and speeds are greater at the upper ranges of edifice.
The facing system must hold lastingness and freedom of care.
The minimal frequence and extent of work is necessary to keep the minimal functional demands and acceptable visual aspect of the facing. As an case, the glass facing requires frequent cleansing and reclamation of seal to keep its public presentation whereas the sheet metal cladding demand to be observed and carefully take attention of it as it is easy undergo oxidization procedure and faded.
The facing system has the control of internal temperatures.
This is due to the solar addition through the glass panels. The internal temperature can be controlled by three ways. First is by utilizing a deep recessed window in concurrence with external perpendicular fives. Second, by utilizing non-transparent external louvres and thirdly is by utilizing a particular solar control glass.
The facing system has a great opposition towards fire.
The system must carry through the edifice ordinances by the local authorization. The stuffs used as a liner for insularity must be made from a non-combustible stuff.
The facing system should include thermic belongingss by commanding the radiation and conductivity of heat.
The liner of the cladding stuff demand to supply extra insularity to command the heat. To radiate the flow of heat from the Sun, the interior surfaces of the cladding demand to be at the temperature that will non do radiant uncomfortableness which is neither excessively hot nor excessively cold. To command the conductivity of heat, the facing must be made from a low conduction of heat stuff to avoid localized condensation on interior surfaces, thermic Bridgess and stabilised the needed grade of the conductivity of heat into and out of the edifice.
The facing system should be equipped with sound insularity.
The facing system should insulate the noise outside the edifice from the inside of the edifice or the inside of the edifice from the external noise. The isolation of noise is best achieved by walls that posses the characteristics of airtight, monolithic and resilient. The used of resilient tablet to forestall sound arising within the construction to be transferred vertically through the cladding members. The airborne sound can be prevented by using dual glazing panel to windows country.
The cladding systems must supply sufficient gaps for the entree of natural daytime and airing.
The entree of the sunshine into the edifice must be controlled as the sunshine has ultraviolet beam which is harmful towards human tegument and must be kept off from inferior stuff that easy disintegrate or fade. The seeable visible radiation of sunshine is utile for light but it can besides be bothersome because it causes blaze.
Question 2 ( B )
A client requires a route that requires small care with sensible non-skid belongingss. With the assistance of diagram, suggest a type of route and the building methodological analysis for the proposed route.
The type of route that requires small care and sensible non-skid belongingss is a stiff paving or besides known as concrete route. A stiff paving consists of a concrete slab resting on a thin farinaceous base. The paving may be Unreinforced Concrete ( URC ) , Jointed Reinforced Concrete ( JRC ) or Continuously Reinforced Concrete ( CRCP ) . The concrete slab should be Pavement Quality Concrete ( PQC ) , manufactured, laid and cured harmonizing to the specification required.
Figure 1: Cross-section of Pavement Structure
The basic stiff paving construction consists of subgrade ( bing dirt ) , sub-base class, base class and surface class ( concrete ) . The sub-base class and base class are optional depending on the location of the route to be made. Sub-base bed consists of a thin concrete base and a bed of cement-bound farinaceous base or dirt cement base. The entire thickness of sub-base and concrete slab should be a lower limit of 450mm. The map of sub-base is helping the drainage, protecting the subgrade against hoar, and, in the instance of powdered dirts is to forestall pumping where the expulsion of H2O and silt through articulations or clefts occurs due to the downwards motion of the slab caused by heavy wheel tonss.
The stuffs used as a farinaceous sub-base are crushed stone, crushed scoria, crushed concrete, natural sand, crushed rocks or well-burnt non-plastic shale.
After the arrangement of sub-base bed, an anti-friction membrane is placed over and usually polythene sheeting that performs excess map of forestalling grout loss from freshly laid concrete.
The concrete slab is usually placed by a concreting train that runs on a heavy responsibility route signifier to forestall warp and is bedded in place at least 24 hours before concreting tthe slab. A hopper unit is normally included in the concrete train to feed the concrete on the base through a conveyer belt. This operation may be carry out instead by utilizing a screw-type spreader. Then, the concrete is laid onto the fabric support, followed by the placing of the cloth, a 2nd spreader and compactor unit to finish the slab. Next, a surcharge is placed on the top bed of concrete to derive maximal compression.
An alternate method to put the slab is by utilizing a slip-form paver. This works requires no side signifiers and mounted on sycophant paths. It is capable of laping paving at 2m per minute.
The general method of stiff paving costruction consists of arrangement, consolidation, coating, bring arounding and jointing.
This procedure involves equipments and processs use to put the pre-cast concrete on a coveted thickness of surface. The concrete can be pour and spread by utilizing truck or truck fond regards. For a more accurate and even arrangement, a placementmachine can be use alternatively. The concrete will go less homogeneous or tend to segregate after it has been unloaded from the truck. Therefore, the screeding procedure is carried out instantly after the concrete arrangement. The extra part of approximately pre-cast concrete are cut off to the needed degree of slab lift. This can be done by dragging a straightedge at the needed lift across the slab.
Figure 2: Placement Over Dowel Bars in an Intersection
Figure 3: Placement in Front of a
This procedure is use to extinguish unwanted nothingnesss in any ways possible. This procedure removes unwanted air nothingnesss and doing it to travel around reenforcing steel or other possible obstructor and therefore, makes the newly placed pre-cast concrete more unvarying and compact mass. The procedure of consolidation is completed by utilizing a vibrator that can be characterised as a long and slight quiver rods. The vibrator works by traveling back and Forth to revolve an bizarre weight which causes the atoms in the pre-cast concrete mass to excite to travel near together for a better flow around obstructor. However, the vibrator demand to be controlled carefully as the exccess or excessively small quiver can do the harsh sum atoms to be non-uniformly distributed.
Completing procedure involves all the stairss and equipment used to make the concluding surface coating and texture of fresh pre-cast concrete. This procedure can be divided into two parts ; drifting and texturing.
Floating. This procedure involves different tools and may utilize multiple base on ballss over the same surface. This is done by running a level surface across the concrete to take high and low musca volitanss, extinguish the imperfectnesss, and pack the howitzer at the surface for texturing.
Texturing. The concrete is rather smooth after the natation. So, texturing procedure is carried out to make a faux pas opposition surface for traffic. The form is done by dragging a rough-texture point across the surface. There are two types of texturing ; microtexture and macrotexture.
Microtexture. The texturing is done by dragging a subdivision of unreal sod or gunny behind the paver. This can heighten frictional force between the tyres of vehicles and the surface of paving and therefore additions safety at lower velocities.
Macrotexture. The texturing is done by tining the paving surface. This type of texturing allows the H2O to get away from between the Surs of vehicles and the paving and therefore increases the safety at high velocities.
Figure 4: Microtexture Figure 5: Macrotexture
The hardening procedure is the care of needed temperature and satisfactory wet in pre-cast concrete as it hardens to develop coveted belongingss such as strength, lastingness and denseness. These belongingss related to the extent of hydration of concrete which depend on the wet and temperature of the site. The flawlessness of the hydration can consequences in the better concrete ‘s belongingss.
This procedure involves the actions to infix purposeful discontinuities in the paving and seal them suitably. Joints are formed in slab for leting and commanding the motions such as enlargement, contraction and warping. There are two types of stuffs used in articulations, a sealant that separates the slab and a waterproofing compound that fills the top of articulation. The stuff used as a joint fillings are cork, gum elastic or sheet bitumen.
On completion, the surface of the slab may be textured by brushing with a wire broom at right angles to the centre line of the carriageway to gives a better skidding opposition and unvarying visual aspect. The slab should be cured instantly after coppice intervention by spraying with a bring arounding compound.
Question 2 ( degree Celsius ) :
Describe the public presentation and stipulate the stuff that can be used to make full the nothingness of obsolete constructions, e.g. – culverts, excess cloacas, basements, and cellars and besides for dirt structural stabilization, e.g. – span abutments, tunnel stabilization, and embankments.
The stuff that can be used to make full the nothingnesss of obsolete construction is foamed concrete. Specifically, it is called Highly Air-entrained Mortar ( HAM ) or besides known as aerated concrete. Ready-mix froth concrete is extremely feasible and incorporate up to 50 per centum air-entrained which lead to a low denseness stuff. This type of concrete can self-levelling, self-compacting and can be pumped with the hazard of colony snap and plastic shrinking is lower than a normal concrete.
The public presentations of the foamed concrete can be divided into three classs which are fictile province advantages, working betterments and concluding concrete public presentation.
At fictile phase advantages, the foam concrete can be implemented to a assortment undertaking demands and operational conditions as it is more practical than any other stuffs. The characteristics of concrete that satisfy at this phase are as follows:
The concrete can be produced on site or off site. This characteristic allows an immediate arrangement on bringing and therefore, no infinite is needed for storage. This will besides take to nice workability keeping.
The concrete has broad scope of possible mixes of stuffs harmonizing to its use. The proportion of mixture is adjustable to carry through needed public presentation. This may consequences in controlled denseness and strength of the concrete.
The concrete has a stable chemical construction. So, no dirt analysis and wet cheques between beds are required. This is due to its compatibility with about all edifice merchandises and stuffs.
The concrete has a cellular fill. This may do the external taint face troubles to perforate into the concrete.
At the working betterments class, the free-flowing belongingss of these concrete contribute to the undermentioned characteristics and benefits:
The concrete is easy to put and complete. It uses merely a individual procedure of installing where the concrete is pour and so levelled. This lead to a decrease in cost for labor and supervising. Besides, the specialist machinery such as compactors or vibrators is non needed.
The froth concrete is pumpable. They can be pumped at a important distance by utilizing a simple conventional concrete pump.
The concrete is self-compacting and self-levelling. This characteristic makes it ideal for an unaccessible trench where the compression is hard to transport out. It allows the concrete to dispatch into narrow infinite and to the full fills the nothingness.
At concluding concrete public presentation class, the plastic province qualities have eventually translated into important concluding public presentations. The public presentations are as follows:
The concrete has high entrained air content. This characteristic makes the concrete becomes more opposition towards stop deading or thaw harm. The entrained air content besides acts as a good thermal and acoustic insularity.
The froth concrete has a good coherence. The coherence makes the concrete as a stable froth construction that reduces colonies. The coherence besides helps in the decrease of hemorrhage and segregation of concrete
The denseness and strength of the foam concrete can be controlled. The scope of densenesss and strengths is available for each type of foam concrete. The lower strength concrete allows remotion of subsequent entree to services
The froth concrete has a stable construction which makes it can be surfaced after 24 hours.
Question 2 ( vitamin D ) :
Briefly describe the activities involved in external plants at the start of the contract.
External plants can be by and large defined as the building works done externally from the chief edifice. The external plants can be divided into two ; at contract beginning and at the terminal of contract. The activities involved in external plants at the start of the contract are drainage, impermanent entree and edifices, and public public-service corporations whereas the activities involved at the terminal of contract consists of route and paving, fence, landscaping and minor external plants.
Drain can be divided into two types ; underground/subsurface drainage and surface drainage.
Subsurface drainage was made to roll up the H2O from where it is non wanted to some other topographic point such as taking and disposing of excess groundwater from gardens and other secret plans of unfastened land. The system normally deals with disgusting H2O from kitchen, lavatories and any industrial procedure or uniting disgusting H2O with surface H2O. The subsurface drainage system consists of belowground pipe line, manhole/inspection chamber and culvert.
The belowground pipe line pipes and sewer pipes can be made of glassy clay, uPVC, concrete, high denseness polythene ( HDPE ) and many others. The jointing of field ended pipes is made by agencies of a yoke where the socketed pipe that has distinguishable ‘male ‘ and ‘female ‘ terminals must be laid with ‘female ‘ terminal indicating upstream.
To build belowground pipe line, the pipes should be laid in consecutive line from point to indicate with a autumn to a steady gradient. The type of bedclothes is depending on the pipes stuff to protect the pipes from ruptures or breakage. The adjustments and entree points must be installed at caput of tally, crook or alteration of way, alteration in pipe diameter and at junction, unless all tallies connected to junction can be rodded from another entree point.
The 2nd portion of subsurface drainage system is manhole, entree point and review chamber. The entree Chamberss are intended to supply simple entree for casual review and entree for drain rods or other care equipment. The review Chamberss ( IC ) are larger than entree Chamberss. It provides entree for care equipment, but tends to hold more subdivisions feeding into them. The manholes ( MH ) are the largest Chamberss supplying entree to sewer or run out for care equipment. The manholes can be made from brick ( brick manhole ) or pre-cast concrete manhole. The brick manhole typically have 215mm thick brickwork with a mass concrete as benching whereas the pre-cast concrete manhole merely 50-60mm midst, although those built beneath vehicular trafficked countries should hold been haunches with mass concrete at least 150mm midst.
Figure 6: The Cross-section of Pre-cast Concrete Manhole
The 3rd portion of subsurface drainage system is culvert. Culvert is a construction which provides a waterway or other opening under a route. The type of pipe culvert should be category Z spun reinforced concrete with spun concrete neckbands or taps and socket type.
Figure 7: The Culvert
The 2nd type of drainage is surface drainage system. The system collects H2O from the roof and the pavement, frequently dispatching this comparatively clean H2O into a local watercourse to cut down demand on the wastewater intervention works. The surface H2O systems are gulley and entree point, uninterrupted grating over pre-cast concrete channels and combined curb and drainage systems.
The gulley and entree point can be classed into single trapped gulley and route gullies. The person trapped gully normally used with rainwater downspouts for run outing big country of pavement. The route gullies are fundamentally much larger and used within carriageways.
The uninterrupted grate over pre-cast channels can be made from broad scope stuffs such as HDPE, polymer concrete and chromium steel steel.
The combined curb and drainage systems act as route isolator and discharge point of gathered surface H2O.
Figure 8: The Kerb
Second external works done at start of the contract is the building of impermanent entree, storage country, auto parking and site installations. These are the major constituents to be built before any building of edifice can take topographic points in proviso of hard entree to all parts of the site, troubles in storage of stuffs and for the site installations and auto parking.
For the building of impermanent entree, the contractor will put the basal class of lasting route to understate the cost. The site impermanent route can be kept dry by puting the drainage system every bit shortly as possible.
The 3rd external plants at the beginning of contract is the public utilities services. The services that involves are H2O system, electricity and telegraphing for telephone. The public public-service corporations need to be planned in front before any major constructions are built. Any buildings of service brinies and canals should get down at the same time with foundation building phase so that it will non impede the building activities.