Grapevines on land the pipes are foremost laid out, an operation called ‘stringing ‘ along the path. The pipes should manage with slings of canvas or other non-abrasive stuff to forestall harm to the pipes, which should non be dropped, dragged or rolled. Pipes necessitating welding or other signifiers of jointing before being lifted into the trench are placed on lumber skids. Long pipes should be cleaned out anterior to alignment and jointing.
Trenching is carried out by particular impinging machines or hydraulic backacters. Depending on the length and location, the articulations in the grapevine may be completed before raising into the trench, takes topographic point utilizing side-boom tractors or similar works ( Figure 1 ) . Alternatively, the pipe may be lowered into place foremost and so jointed ( Figure 2 ) . All grapevines should be sealed with dark caps and the terminal of a twenty-four hours ‘s work to forestall immersion of little animate beings and other objects.
The readying of the trench for pipes will depend on the type of stuff used for the grapevine and will run from a bed of farinaceous stuff to carefully molded sand beds ( Figure 3 ) . On no history should hard packing stuffs used to raise or pack up the pipes be left in place. Heavy pipes may be lifted by pneumatic lifts to take the initial wadding before being dead on sand bags or farinaceous stuff.
The trench should be 300 mm wider so outside diameter of the pipe, extra room being necessary at each joint to supply sufficient room for articulations to be made and inspected. In difficult or bouldery land the trench should be taken deeper than the needed deepness and brought to degrees or gradient with farinaceous stuff. Backfilling should be completed every bit shortly as the subdivision of pipe has been tested, this will forestall the pipes drifting in instance of a storm. Testing should be preceded by cleansing, this is achieved by agencies of a ‘foam-pig ‘ ( a cylinder of stuff, such as expanded polystyrene, driven through the pipe ) . Pipelines traversing roads, railroad lines or rivers should be sleeved, the sleeved being placed by the unfastened trench method, power driven auger or thrust-boring. The diameter of the arm should be a lower limit of 100 millimeters greater than the outer diameter of the grapevine.
Figure 1
Hoisting and puting 900 millimeter welded steel gas line
Figure 2- Hoisting and puting a 600 mm Figure 3- Fixing the sand base for a
Ductile Fe H2O pipe 1.83 m Defense Intelligence Agency steel grapevine
The grounds of different bedding type for glassy clay ( stiff ) pipes and ABS ( flexible ) pipes are:
1.Trench width- one of the first things to see is the trench breadth.
Vitrified clay pipes- this “ stiff ” stuff does non depend on sidefill stiffness, so the trench can be every bit narrow as the installer needs to do joint connexions.
ABS pipes- as a “ flexible ” stuff it is dependent on side fill stiffness to restrict warps. Width of the trench should be increased because to let compression equipment to run in the infinites between the trench walls and the pipe. The extra compression is required to heighten the flexible stuffs sidewall stiffness.
2.Trench bottom- the underside of excavated trench must be steadfast, even, and stable
Vitrified clay pipes- the trench underside must be level with hub or matching holes provided so that the pipe is uniformly supported. No particular bedclothes is necessary, unless the pipe is installed in stone. ( In stone diggings, a six Iraqi National Congress bed of sand or selected backfill is suggested to protect the pipe from crisp projections ) .
ABS pipes- the trench underside must be provided with a lower limit of 4 inches of bedding unless otherwise specified. The bedclothes stuffs varies by dirt type. In stone diggings, a minimal shock absorber of six inches is required below the underside of the pipe.
3.Compaction of backfill- the pipe one time installed and inspected must be backfilled.
Vitrified clay pipes- particular compression of the backfill is non necessary except for run intoing the demands of normal compression of the excavated country. Since dramatis personae Fe is “ stiff ” , it does non depend on sidefill support.
ABS pipes- the “ flexible ” pipe design is dependent on sidefill support to derive “ stiffness ” to command warps within acceptable bounds. Compaction in six inch maximal beds is required to the springline of the pipe. Compaction around the pipe must be by manus.
4.Deflection- warp in all piping stuffs must be controlled in order to forestall obstructor to flux and guarantee that the articulations remain unafraid.
Vitrified clay pipes- because it is stiff, warp of the pipe wall is about non-existent.
ABS pipes- a flexible pipe is dependent on sidefill support to derive “ stiffness ” and some warp of the pipe wall is both normal and expected. This warp must be controlled within pre-determined bound to guarantee clearance for review, cleansing, meeting flow demands and unity of joint seals. The sum of allowed warp must be determined before installing with a upper limit of 5 % warp.
List down with account the contractor undertaking in landscaping contract
A good contractor is the best option for keeping community landscapes, and a services contract ensures that proper and timely attention is given to all workss, including sod and woody cosmetic such as bushs, trees and thenars. A realistic budget and specially-trained professionals are important elements of landscape protection. A contractor maintains landscape for works wellness and length of service. Other than that, the contractor have expertise in gardening, including rating and intervention of works jobs ( insect, disease, weeds, nutritionally ) , proper chemical use, mowing, sniping and inching methods, and other elaborate demands. A contractor with specially-trained staff, such as a certified tree surgeon or pest control operator, is even more effectual but may be more expensive at first. However, the extra cost in contracted care fees is little monetary value to pay compared to the cost of replacing sod and landscape workss damaged by disease and insects. Lawn mowers, inching equipment, spreaders, sprayers, and specialised manus tools are needed to decently keep deep-rooted beds and turf countries. A contractor besides needs to understand the capablenesss of the equipment to guarantee optimal public presentation.
The specification should sketch the services the contractor will execute, while the care agendas should include a clip frame for the assorted public presentation demands contained in the specification. It should include at least, cut downing and inching, sniping bushs, thenars, and trees, fertilisation of lawn and landscape beds, insect and disease control, weed control and care of the irrigation system. The care agenda covers the full contract period, saying in item when the contractor is expected to execute the assorted undertakings. The agenda can be used as direction tool to supervise the contractor ‘s public presentation. Contractors are normally expected to execute specific undertakings, under normal clime conditions within a two to three hebdomad period. Therefore, the clip frame stated in the care agenda should be in monthly increases. This clip period provide flexibleness for the contractor.
The public presentation standards should sketch the contractor ‘s specific activities in the countries of sod direction, bush, tree, thenar, and bed care, litter remotion, and killing. The public presentation standards should cite all stuffs and merchandises to be used and provided by the contractor. Detailss sing types of fertiliser, pesticides ( insect powders, antifungals, weedkillers ) , and mulch should be included here with some commissariats for tantamount options.
Insurance demand must be clearly defined in the contract, including public presentation rating, legal construction and linguistic communication. It is of import that the contractor ‘s and the association ‘s insurance on their ain General Liability policy. Although the bounds will be upon to the board of managers, the policy at the really least should be on a “ comprehensive ” signifier and an “ happening ” footing. The policy should include premises and product/completed operations coverage.
Second, the contractor policy should include the same signifier, footing, and coverage as the association. In add-on, the policy every bit good as certifications provided should include the undermentioned coverage or indorsement, aggregative applies per undertaking, XCU ( detonation, prostration, and belowground jeopardies ) exclusion deleted, the association, its members, invitees, and agents named as extra insured, contractual liability, and a clasp harmless understanding in favor of the association for bodily hurt, personal hurt and belongings harm. Limits should be equal for the extent of the services provided. The insured subcontractor selected by the contractor must be licensed to make concern in the association ‘s legal power. The association should necessitate the contractor to transport Workers Compensation insurance with employers liability and a release of subrogation for the work or occupation performed. Certificates should be sent to the association ‘s insurance agent for reappraisal. The contractor ‘s insurance demands can be placed in the legal organic structure, in the specifications under the header of general demands, or in an insurance subdivision.
The contractor ‘s cardinal employee should be an cosmetic plantsman, whose cognition and preparation is critical to landscape problem-solving. The plantsman specializes in flowers, bushs, thenars and trees. The agronomist specializes in dirt and turf direction and may be good for an association with big countries of sod. The size of the house has little to make with the competence or capableness to execute, and it is best non to put excessively much accent on size. Contractors should supply mentions, sooner from associations of similar size and landscape.
Harmonizing to general criterions, contractor shall demo cognition of location ( specific site conditions ) , indicate out preexistent conditions and program for disciplinary actions, have a certification of insurance with required coverage ( including Worker ‘s Compensation ) , provide written studies ( monthly, due day of the month, content, service tickets ) , provide all stuffs, tools, equipment, and labour, perform at highest criterions, have a Green Industries Best Management Practises ( BMPs ) certification of completion offered by University of Florida IFAS Extension Service, execute harmonizing to state, province and federal ordinances ( including any related to fertilisers and pesticides ) . The contractor shall complete all labour, supervising, equipment and stuffs as necessary to supply complete care and irrigation of all bushs, trees, thenars, land screens, one-year and perennial workss and lawns, and shall supply such other work as may be required by these specifications to keep the landscape in an attractive status throughout the twelvemonth.
Turf attention, cut downing and inching, all grass must be maintained at the recommented tallness, utilizing mulching, rotary type, mowers. Mowing must be directed off from H2O organic structures and imperviable surfaces. Turfgrass cuttings are a beginning of slow release N. Leaving the cuttings, instead than taking and bagging them, reduces both fertilization demands and the sum of works stuff that must be disposed. For fertilisation, do non fertilise when heavy rain is expected. Leave a ring of duty around or along H2O organic structures. The usage of deflector shields on fertilizer spreaders is recommended around or along H2O organic structures and imperviable surfaces such as pavements and roadways.
degree Celsius ) Briefly explain three ( 3 ) influencing factors for route design
First of the act uponing factor of route design is type of subgrade. For appraisal of the design wet content under impermeable asphalt come uping are classified into three classs.
In class one the H2O tabular array is sufficiently near to the land surface to command the subgrade wet content. The type of subgrade dirt governs the deepness below the route surface at which a H2O tabular array has a dominant influence. For non-plastic dirts, flaxen clays and heavy clays the H2O tabular array will rule the subgrade wet content when the distance from the route surface is less than 1 m, 3 m, and 7 m severally. The best and easiest method of measuring the design wet content is to take measuring below similar, bing pavings during the moisture season. If there is no bing route in the locality, the design wet content can be estimated from measurings of the deepness of the H2O tabular array and finding of the relation between suction and wet for the subgrade dirt.
In class 2, the H2O tabular array is deep but the rainfall is sufficient to bring forth important seasonal alterations in the wet conditions under the route. This state of affairs occurs when rainfall exceeds evapotranspiration for at least two months of the twelvemonth. The rainfall in such countries is normally greater than 250 millimeters per twelvemonth and is frequently seasonal. In this instance the subgrade wet status will depend on the balance between the H2O come ining the subgrade through the shoulders and the wet go forthing the land by evapotranspiration when the conditions is dry. The design wet content should be taken as the optimium wet content.
In class 3, the lasting H2O tabular array is deep, and the clime is waterless throughout the twelvemonth. Such countries have an one-year rainfall of less than 250 millimeter. The wet content of the subgrade is improbable to transcend the optimium wet content given by the standard compression trial and the wet content should be used for design intents.
Second factor that influence route design is skidding opposition. The skidding opposition of a route is a step of the clash generated between the route surface and a Sur in wet status. In any peculiar location, the clash depends on belongingss of both the route and the Sur, with clime factors besides holding an influence. The cardinal belongings of the route surface in bring forthing skidding opposition is the microtexture of the stuff in the surfacing which is in contact with vehicle Surs. In asphalt and exposed-aggregate concrete surfacing, the microtexture is determined by the all right construction of the surface of the aggregative atoms. When a route is trafficked, its skidding opposition is reduced as a consequence of the smoothing action of Surs on the microtexture. Accelerated smoothing machine to measure the belongingss of different sum was designed. In this trial, samples of sum are set in rosin to organize specimens which are mounted on the perimeter of a wheel. This is so roated for a period of clip while a gum elastic Sur is loaded onto the aggregative surface and a polishing medium trickled into the interface. At the terminal of the shining procedure, the skidding opposition of the specimens is measured and compared with the consequences from specimens made with a control rock. Some sums perform better than expected whilst others appear to smooth more and hence give lower skidding. In order to give a satisfactory public presentation in footings of skidding opposition criterions, the stuff should be provide peculiarly, it was necessary to reexamine the demands in the visible radiation of experience.
Third factor is initial cost. The cost of geting new right of manner is a important factor in the planning of any interchange. The cost of upon land for an interchange can change from as a small as per square pes to every bit much as per square pes in a extremely travelled and populated urban country. If edifices or other belongingss are in the possible right-of-way country, the cost per square pes may be much higher than per square pes and can transcend per square pes in particular instances where major edifice are taken. Clearly, cost of right of manner can be the commanding factor in the general economic feasibleness of the proposed undertaking. The larger the separation the more right-of-way country required and, therefore, a possible addition in cost for geting the land. Pavement costs for the major route, and the entryway and issue inclines represent a 2nd important cost constituent. At the conceptual estimation degree, pavement cost includes the readying of subbase, the paving stuff itself, i.e. , asphalt or concrete, and medians.
Pavement costs are estimated as a map of the entire square pess of route surface country and the unit cost per square pes of surface country. The square pes of pavement country is determined by the breadth of the route, less kerbs, and the length. The unit cost would cover subbase and all paving building. Unit of measurement cost are likely to change depending on the thickness of the paving, the type of pavement, i.e. , jointed concrete pavement, handiness of stuffs and volume of current building. Two primary cost constituents are earthwork and retaining constructions associated with the major route. These two constituents can consist between 10 and 20 per centum of the entire cost of building. Earthfill is used to fix the slope incline for the major roadway from where the major route deviates from bing class to the beginning of the span construction on either side of the span. If the major route base on ballss under the cross route, earthwork consist of digging bing dirt and taking it from the site. Variations in cost besides are due to the type and handiness of stuffs, dirt features, draw distance, location of fill and volume of dirt required. The major route is frequently bordered by a concrete retaining construction unless sufficient right-of-way is available to utilize aslant.
vitamin D ) Briefly explain four ( 4 ) demands of articulations for cladding system.
The demands of articulations for cladding system are exclude air current, rain and snow, let for structural, thermic and moisture motion, good lastingness, and easy maintained and maintain the thermal and sound insularity belongingss of the environing facing. These demands can briefly explicate under two headers of suited articulations.
Filled articulations are by and large satisfactory if the facing faculty is little since if incorporated in big faculty panels filled articulations can check and let H2O to perforate. This failure is due either to the filling stuffs being incapable of suiting motion or a dislocation of adhesion between the make fulling stuff and the panel. Filled articulations are non easy to build and trust chiefly upon howitzers, sealers, mastics or preformed gaskets to supply the barrier against the infiltration of air current and rain. They are limited in their public presentation by the sum that the sealing stuffs can suit motion and certain extent their weathering belongingss such as opposition to ultra-violet beams.
Drained articulations have been designed and developed to get the better of the disadvantages of the filled articulation by planing the joint to hold a drainage zone and providing and airtight seal at the rear of the joint. Drained articulations have two constituents which must be considered, viz. the perpendicular articulation and the horizontal articulation.
Vertical articulations consist fundamentally of a deep narrow spread between next panels where the rear of the joint is adequately sealed to forestall the transition of air and wet. The breadth of the articulation does non significantly affect the sum of H2O making the rear seal since most of the H2O come ining the joint ( about 80 % ) will make so by following over the face of the panel, the reminder ( about 20 % ) will come in the joint straight and most of this H2O come ining the articulation will run out down within the first 50 millimeter of the joint deepness. Normally the make up one’s minding factor for finding the joint breadth is the type of mastic or sealant being used and its ability to suit motion. Checks on the sum of H2O come ining the drainage zone such as ribs to joint borders, exposed aggregative external surfaces and the usage of baffles.
Baffles are loose strips of stuff such as neoprene, butyl gum elastic or plasticised PVC which are unaffected by direct sunshine and act as first line of defense mechanism to H2O incursion. The baffles are inserted, after the panels have been positioned and fixed, either by drawing them through prepared channels or by direct interpolation into the turn uping channels from the face or dorsum of panel harmonizing to the joint design. Care must be taken when infixing baffles by the pulling method since they constantly stretch during interpolation and they must let to return to their original length before paring off the excess to guarantee equal screen at the intersection of the perpendicular and the horizontal articulation.
The equal waterproofing at the dorsum of the articulations is of extreme importance since some H2O will normally perforate past the unfastened drainage zone or the baffle, and any air motion through the joint seal will besides help the transition of H2O or wet. Drained articulations which have merely a dorsum of seal or a baffle and seal can hold a cold span consequence on the internal face giving rise to local condensation, therefore consideration must be given to keeping the continuity of the thermic insularity value of the facing.
Horizontal articulations are normally in the signifier of vitamin E rebated lap joint, the upper panel being lapped over the top border of the lower panel. As with the perpendicular articulations, the proviso of an equal back seal to forestall air motion through the articulations is of paramount importance. The seal must besides execute the map of a compaction articulation, therefore the waterproofing strip is of a compressible stuff such as bituminised foamed polyurethane or a performed cellular gum elastic strip.
The profile of the joint is such that any H2O come ining the spread by fluxing from the panel face or by being blown in by the air current is encouraged to run out back on to the face of the lower panel. The deepness of joint convergences is normally determined by the grade of exposure ranges from 50 millimeters for normal exposure to 100 millimeter for terrible exposure. It must be noted that the effectual convergence of a horizontal articulation is measured from the bottom border of the baffle in the perpendicular articulation to the seal and non from the rebated border of the lower panel.
Intersection of articulations is an of import characteristic of drained joint design and item since it is necessary to cast any H2O run outing down the perpendicular and horizontal articulations intersect because the articulations are designed to provide merely for the entry of H2O from any one panel connexion at a clip. The usual method is to utilize a flashing get downing at the dorsum of the panel, dressed over and lodge to the upper border of the lower panel. The pick of stuff for the flashing must be carefully considered since it must accept the burden of the upper panel and any motions made whilst the panel is positioned and secured. Besides it should be a stuff which is lasting but will non give rise to staining of the panel surface. Experience has shown that suited stuffs are bitumen coated woven glasscloth and man-made gum elastic sheet.
Typical filled and drain articulations – – Typical horizontal articulations –
REFRENCES
Construction Technology, 2nd edition by R Chudley.
Advanced Construction Technology, 4th edition by Roy Chudley and Roger Greeno.
hypertext transfer protocol: //books.google.com.my/books? id=mKm0
