Selection of Materials and Labour in Construction

Selection of Materials and Labour in Construction adapted selection of materials and labourInsitu rein extortr c every crop and geomorphologic gustbrand atomic sum 18 popular and dominates in the framing market of multi storey constructions. through with(predicate) the in a higher direct evaluation we found that the insitu rein personnel officement concrete mold ins materials and labour is pretty pr doic each(prenominal)y s exalteds then steel and precast concrete surround. and so, we recommend exploitation insitu rein pull backment concrete variety accession in this development. personifyCost is all toldness of the crucial f deedors take in to be considered in the selection of morphological framing options and this costs of puked structures support be collide withed by the market condition. Through our experience and market analysis, we found that the insitu reinforcement concrete frame is much cost efficiency compargond to the others fibre of structural frame. This is over pay adequate to steel is particularly volatile and ever so influence by the switch over governs due to international competitions. Adversely, cement price is much st commensurate and according to BCA (2007), the statistic claims that the UK average cement price is stable over the in conclusion 10 years and it is raised below the inflation rate. Cement is one of the main components in the concrete mixture and thus bewilder the concrete price generally result be cheaper. Therefore it is wisely no to propose steel frame as its price fluctuate much frequently in comparing with concrete.Speed of tourIn prescript, the insitu reinforcement concrete frame has a dis improvement in term of habitusula speed it is relatively slow due to the condemnation consumed for curing. However, lead meter for steel frame personationually is higher than insitu reinforcement concrete frame be hunting expedition one of the reasons is due to the steel frame need to pre-fa bricate in pulverization and it is requires a number of fabrication do byes.Lead m can be defined as the actual time counted from putting in an read (by the builder) until to the actual construction one billet of a particular fraction. jibe to the lead time figure published in the Chartered cadence Surveyor (1992), show that insitu reinforcement concrete frames lead times is 2-8 weeks and it is less than the steel frames lead times with 8-14 weeks. Hence, the insitu reinforcement frame constructions total construction time would be shorter if comp ard to steel frame. Although steel frame construction has an advantage in term of faster structural erection time provided in our opinion the shorter total construction time produced by insitu reinforcement frame construction is to a greater extent crucial. Therefore, the insitu reinforcement concrete frame construction is more suitable and is recommended in this forcing out.Ability to standardiseThe insitu reinforcement concrete frame is more flexible and tolerant in any trans actation during the construction process. Any subsequence alteration is straightforward and it would non much affect the following construction sequence, process, cost and importantly greater delay would non go past. But, both the steel and precast concrete frame has disadvantages in the powerfulness to standardise. This is due to both are factory prefabricated products and later only bring back to site for installation. Therefore any subsequence alteration in steel frame or precast concrete frame construction any in physique or construction sequence depart caseful an impact in the factory production cable television service as entertainably as to the subsequent following construction planning process. ardor foeThe insitu reinforcement concrete frame has underlying brush off resistance advantage compared to steel frame which fire resistance factor is not inbuilt. Therefore steel need playitional fire protection work and this today go forth involve additional construction time and cost.Size and genius of siteAs mentioned above both of the steel and precast concrete frame are prefabricated in the factory. Therefore, it has a disadvantage and limitation in producing huge structural frame during the prefabrication process and installation process at site. Similarly the delivery process of prefabricated huge frame exit withal tough and long and not practical. But, this does not happen to the insitu reinforcement concrete frame where the huge structural elements can be adjusted and produced on site by constructing it in small part each time with pop break affect by the factor of size and nature of site.Finally we would manage to propose that this 10 storey edifice to be constructed by exploitation insitu reinforcement concrete frame construction due to the above mentioned advantages. In addition, this insitu reinforcement concrete frame is more utiliseful in accomplishing jet process comp ared to steel frame. Adversely, we in addition do not negligence on the disadvantages points of the insitu reinforcement concrete frame such as timber restrict, massive construction process and etc. However, this insitu reinforcement concretes existent disadvantages factors can be subordinated to an acceptable take by adopting a straitlaced site management placement and well planned construction process.REFERENCESConstruction engineering 5, Heriot-Watt UniversityComparison Of Reinforced In-Situ Concrete And Structural Steel In Multi-Storey Building purgework Construction, RIAD QUADERY (ICE Membership Number 64405090)BCA (2007Chartered Quantity Surveyor (1992) unit of measurement 1 (c)In straddle to change swan the build height to 30 storeys, the previous proposed structure need to consider and cope efficiently to the sombreness onuss and resists substantial side(prenominal) turn ons or sway force name by wind, while at the corresponding time, not presenting undu e self weight freightages on the foundation system. Therefore, whatsoever alteration in term of frame pass on need to take into precondition for achieving the tall construct protrude safety factor.According to Chew, Y L M., Construction engineering for Tall Buildings (2nd Edition), the amount of materials needed in a tall building to resist gravity tons is almost bilinear with its height, however the amount of material needed to withstand lateral forces increases with the uncoiled of the wind speed. The bet 2.1 below is an illustration of the lateral forces enforce by wind increase exponentially with the building height.A) Introduction of pluck attach Shear fence StructureShear smothers unremarkably is reflected to the steep elements in the lateral force resisting system (LFRS). This prune beleaguer is very known contain in many structures. For stuffy concrete frame system, pluck wall is designed to function as a deep, thin upended cantilevered line of pro ducts outs members where it is robustly connected from the roof level onto the foundations level. While at the same time the insitu reinforcement concrete deck are designed in robust connection into the shear wall (vertical element) and performing the function as a horizontal diaphragms to enchant lateral loads to the vertical element and subsequently into the foundation. Please refer the below illustration of Diaphragm of Shear wall ( consider B), Shear Wall Action ( consider C), Diaphragm Action (Figure D) andFor this 10 storey office building, it is design with a symmetrical floor layout and this layout gain grounds it fitly to create few shear wall system. that this shear wall design and its implementation impart only involve near shaver ar trimment and structural design alteration, such asalter the type of foundation,convert the existing wall element become vertical reinforcement concrete wall,change the floor system in order it essential be robust adequacy and able t o transfer the lateral force to the shear wall inwardly the limit of design deflection.Similarly the design of the beam (underneath at feed quadruplet theater of operations) must be stiffly tied into the supporting shear walls make sure the lateral load can efficiently for transfer to the foundation.With the above alteration the whole shear wall bequeath be make (refer layout plan power grid line A-B/3-6 F-G/3-6) and this new created system not only carries vertical load but it floor system acting as a diaphragm to transfer the lateral loads to this shear wall and then transfer those load to the foundation efficiently. With this alternative design the building height pull up stakes able to achieve 30 storeys and maximum to achieve 35 storeys height. Besides, through this start the overall building concept will be remained unchanged.B) Introduction of Frame Using Vertical Trusses, Belt Trusses and /or Outrigger TrussesThis concept is development from the preceding shear w all. The purpose of this design is to provide a vertical hold fast call Outrigger Trusses where it is robustly connected to the perimeter mainstay/exterior mainstay with the purpose to form a much stiffer structure at impertinent column and enables it to resist greater wind forces or other form of lateral load, as well as the resistant of gravity load. In addition the Belt Trusses will be built and it is surgical operation in wrapping through the perimeter column at the same level as the outrigger corbeles to further stiffen of the structure.This design is suitable in maintain to amend this building height into 10 storey. The Figure E and Figure F below shown dickens diagrams to ornament the concept of this vertical trusses, tap trusses and outrigger trusses.In order to follow through this concept in this project, the perimeter building column (window dressing column) will be tied by using beam act as outrigger trusses and robustly connected to central core (also act as sh ear wall). Through this alternative frame solution the whole structure will act as a large system will enabling a structure approximately 25% stiffer than a original structure solely relying on a shear truss or shear wall system while without changing the floor plan arrangement. Figure F shown how the outrigger truss combine with shear wall to further enhance this whole building structure to resist lateral forces.C) Introduction of Tube System and Bundle Tube SystemThe organ pipe system has been the most efficient structural system go ford for tall building. This thermionic tube approach creates a 3 dimensional system (Refer Figure G). This system can be formed by using the conventional frame system where the outside(a) columns around the perimeter of the building are designed in much closer unitedly. Subsequently, these columns around the corners of the four building frontals are tied robustly with short beam and will form a continuity system around all four facades and in ef fect create a structure similar to a huge concussion section that cantilevers from the foundation to the top of the building. This structural system capable in resisting lateral forces in any direction as in article of belief a Box section has inherent strength.This tube system is suspend to adopt in order to increase this building height to 30 storeys. From this building existing layout design (in term of shape) it is suitably to form a Tube shape. Therefore, according to this tube system design criteria, the perimeter column (facade column) of this building will be placed much closer (Refer Figure H) and tied robustly by beam surrounded the four facades of the building and become more stiffened. This will enable the whole structure act as a whole system to resist the lateral force as well as functioning to transfer the gravity load to the foundation. The advantages of this tubes system is it is allow fewer intimate columns, and so create more usable floor topographic point.I n addition the above propose tube system can wisely interconnected or combine act as a whole with the existing tube frames, i.e. two number of lift core and the alternative proposed new shear walls (position at grid line A-B/3-6 F-G/3-6), to create and perform another approach call package tube system. Through this combination a stronger structure will be created and efficiently to resist the lateral forces and gravity loads. The Figure F illustrate the bundle tube system and through this integrate structural frame it is definitely will become more efficiently to resists lateral loads or sway force cause by wind.As a conclusion, with the above solution of alternative frame design (i.e shear walls, vertical trusses, belt trusses and Outrigger Trusses, tube system). This building will be able to increase to 30 storey height with any one of the above wiz alternative frame design. However it is advisable to combine those approaches by looking at at the advantages and permission of t his existing symmetrical building layout with the objective to resists significant lateral loads or sway force (cause by wind), as well as cope efficiently with the gravity loads (vertical load). Moreover theses combination will not cause many changes in terms of the original design and the building concept.ReferencesChew, Y L M., Construction applied science for Tall Buildings (2nd Edition),Construction Technology 5, Heriot-Watt UniversityBrick Industry Association, Technical Notes 24C-The Contemporary charge Wall, Introduction To Shear Wall Design, (Sept./Oct.1970)(Reissued May 1988) www.gobrick.comTall Building Structures analytic thinking And Design, By Bryan Stafford Smith, Alex Coull)IntroductionDouble trim facades is very popular apply in many European cities. This wall system is attractive due to its characteristic such as durability, ecology, greener technology, aesthetical assimilateing and etc. This ikon disrobe facade able to provide inwrought airing into a build ing put and also can reduce naught consumption. These mental image skin facades sometimes also referred to as a building in building.DefinitionsThis wall system can be define as a traditional single facade figure of speechd inside or outdoors by a second, essentially shining facade. Each of these two facades is commonly called a skin. Each of the facade skin can be constructed by various different combinations of materials, commonly by two skin of burnished. However, it is also popular to apply an outer layer of glass used together with a solid inner skin. The area amid the two skins can call ventilated cavity or ventilate position. It is purposely in such designed for vertical fashion circulation purposes. The ventilated cavity between the two skins can be in various largenesss, normally range from as narrow as several centimetres to as wide as several metres (in order to form accessible cavities). The cavity width will influence the way that the facade is maintained. This wrinkle circulation blank shell can be used in many different functions, but in the simplest analysis, the air will be drawn into the building by applying the circulation utilises stack effect, so that a natural ventilation effect will be created for the internecine space of the building. However, this cavity space in some other design can be consists of fan supported or machinelikely ventilated.A) earthy VentilationThe design of exterior part of the skin forming a preservative shield for the building and through the circulation utilises stack effect the natural air will be drawn into the internal space of the building, so that a natural ventilation effect will be created. Therefore, the interior comfort would not be affected even though the windows maintain open throughout the whole day.B) Promote Greener TechnologyThe natural ventilation for multistory conditions relatively will reduce air-conditioning loads and thus will minimise the CO2 output produced during the bu ilding operational phase. According to the research, carried out by Franklin Andrews, Professor Michael Wigginton of the University of Plymouth and Battle McCarthy, who represent the United Kingdom Department of Environment, communicate and Regions has shown that ternary skin buildings when compared to advanced single skin building are capable to reduce 50% of CO2 emissions within the cold equable climate prevalent in the United Kingdom.C) Better acoustic withdrawal-improve disagreement protectionBesides improved the noise protection, this double skin facade are capable to gain an excellent acoustic insulation magnitude even though under the windows open condition. The magnitude of the acoustic insulation is equal to that obtained in classical glass facade with the windows closed condition.D) reducing kindleing energy requirementThe air stored in the cavity between the two skins would be heated by the sun rays especially in winter time. Thus improving both the heat-insulating functions of the facade and its caloric cognitive operation and subsequently will reducing the heating costs.E) Reducing temperature reduction energy requirementDouble skin facade can allow for nigh-time cooling of the interior building with make the window in open during iniquity time and thereby lessening cooling loads of the buildings HVAC system. Thus especially, apply during summer time the night cooling can cut obliterate the building energy consumption particularly the costs of air-conditioning in the summer.F) Exploiting solar powerBoth energy consumption and costs are mathematical to reduce by utilize the suns energy particularly with the incorporation of photovoltaic glass. By this method, the air stored inside the cavity will be heat by the solar rays and reduce the energy consumption.G) Increased Natural DaylightingThe double skin facade will improves the access of natural light transmission system into the building space and thus will produce a demote indoor c omfort and give positive effect to occupants health and as well as increase the productivity of office personnel. Physically with this increase natural daylighting will cause a significant reduce in the amount of electrical lighting required because the graphic symbol of light from natural daylight is more preferential to electrical lighting.H) Fire EscapeFor some of the widest cavities (normally width range from 600mm to maximum 2m), located between the two skins will be able to provide a fire escape during fire occur. Therefore, with this back up emergency escape will enable the fire brigade to save more life during there is fire to the building. endThe above have indicated the benefit of double skin facade wall and make it gain a lot of popularity throughout the world.ReferencesConstruction Technology 5, Heriot-Watt UniversityFranklin Andrews, Professor Michael Wigginton of the University of Plymouth and Battle McCarthywww.glassinbuilding.com/double_skin_facadesCoursework Unit 6 (b)The technological challenges that would need to whelm to produce a double skin facade for this building are as below1) Overheating challengesThe overheating fuss may happen especially on fervent day where hot air will collects and emerge at the top air space and this may cause the top floor offices suffer due to this overheating issue cause by this accumulation of hot air in the cavity. Therefore, technically approach to overcome this problem is to design the air space. There are two type of air space, single(a) air space, anddivided air space.The undivided air space will has advantage from the stack effect. On warm days hot air collects at the top of the air space and with the appropriate openings at the top of the cavity, thus will siphon out warm air and at the same time the second-stringer of storage tank air is draw in from the outside.The benefit of divided air space design is it can reduce over-heating particularly on upper floors. It is also can reduce noise, fire and smoke transmission within the division. Moreover, this floor-by-floor divisions add construction simplicity of a repeating unit and in turn can produce scotch savings.From the above, indicate that both air space using the natural physics principals (hot air rises) to draw air upward. We need to highlight that the second type i.e. divided air space by floor is practically apply for fire protection and sound transmission purposes.2) Maintenance Challenges2.1 CleaningAlthough some of the building which is use the replete(p)y glazed double skin facade to achieve an aesthetical pleasing view but its victuals is critical in terms of cleanup process. The air space need to be cleaned more frequently because this area is list to emerge of dust particles which is circulates quickly during the ventilation process. From an research carried out by Terri Meyer, affiliate Professor, school of Architecture, University of Waterloo indicate that glazed double skin facade need to carried o ut full cleaning regularly from 2 to 4 times a year.Therefore, the air spaces design criteria need to consider the imparts of cleaning especially for the continuous cavity. Similarly, others barrier elements such as louvers placed within the cavity must be removable in order to accelerate access during cleaning process. Normally a device called bosuns chair political program which is similar to the window washing rig is used to access the interior space of cavity for cleaning purposes.In some double skin facade design an open grates will be put at floor by floor or at particular place act as the cleaner standing platform and without affected the air flow design.For divided air space or cavity, normally the interior windows will function as the access panels for In some instances, where the cavity is more divided, the interior windows, whether operable maintenance purposes. Therefore the design of air space need a consideration to provide an adequate space for maintenance purposes besides the ventilation functionality. The interior clear dimension for air space is usually range from 600 to 900 mm.2.2 Replacement of Deteriorate Mechanical PartThe hi-tech mechanic which is incorporated for the functioning of double skin facade (particularly in ventilation process) tend to have a higher failure rate and repair cost. The same mechanics also necessitate higher replacement costs. For instances, the replacement of wiring after a certain number of years. Therefore, a preventive checking is need to carry out frequently in order to detect any mechanical problem in an earlier period before its give a negative impact onto the ventilation system. Besides, a right data record and operation manual on those germane(predicate) mechanic device also need to be keep properly. Through this data any cases of malfunction of mechanic device would be able to find the direct causes and the solution can be carry out as soon as possible as well as in finding the suitable spare part replacement within a shorter period of time.3) Control of Natural VentilationFor high-rise building with double skin facade, normally will found a problem on how to control and maintain its natural ventilation (here mean the quality of air) to its occupant. The area between the double skin facade in principle is not affected by high velocity wind because this area have been protected by the exterior skin. Therefore, this region typically will access by the inhabitants for natural ventilation and this will cause some unexpected impact of sound, smoke, noise or heat transfer over this partition off either from one section, level or room to the propinquity area. In order to eliminates these impact efficiently normally this buffer zone will be propose in compartmentalize design and clear up into regions with air supplied by grilles or vents at the individual zone or each level. Then with the use of vents or grilles allows for the control of the incoming air by reducing air velocity, as well as defend from the rain and reducing the noise transmission from the exterior. Regular cleaning process also need to be carried out in order to make sure that the ventilated air is always in good quality such as out of dust particle. Hence, high-rise building is essentially need to plan and implement this control in order all its occupant will be provide with a natural ventilation.4) Fire RegulationAlthough the air space between the skins can be use for fire escape but the fire regulation might cause difficulties if no extra attention is provided. Therefore, for safety measured a proper indication of fire escape route have to provide and place at suitable location at each floor.5) Reduce of infiniteAs mentioned earlier the width of the cavity can be formed from few centimetres until few meters. So, this will cause some reduce in the building usable space. Therefore, it is significant to find the optimum cavity width in order to gain an optimum office space in this building .6) ClimateIn some European country the double skin facade will face the climate issue such as humidity. For those double skin facade associate with the passive design strategies, (i.e. thermal mass) and radiant (hydronic) system , the condensation control will become an issue. Therefore, this critical factor need to be answerd in order it would not give a negative comfort effect inside the building. This problem can be technically solved by adopting condensation control through the appropriated mechanical ventilated system, i.e. extract air system. This system normally apply for location where the natural ventilation is not possible (due to it locations inherent with high noise, wind and fume). Through this system the fresh air will be supply by HVAC and it is precludes the natural ventilation. These systems tend not to reduce energy requirements as fresh air changes must be supplied mechanically. In addition, the occupants are advisable not to adjust the temperature even though hold out to their individual spaces. However, the priority consideration will sleek over be put on the potential use of natural ventilation. For instances, to come out a desirable hours of natural ventilation scheduled through the utilisation supply control system can achieve this objective.7) HVAC Technically DesignThe HVAC will play a major role for the building where the natural ventilation is not suitable due to its negative climate conditions. Therefore, in cases the functionality of a HVAC system will become a significant point and it will give an impact onto the building ventilation system. So, in order to solve that problem, during the earlier design process need to fully integrates architectural and mechanical concerns is need to fully integrates during the earlier design process. By this earlier dot planning will able to achieve a smooth functioning of HVAC system. In economical point of view it will less expensive and it is a wise planning because the cost saving figu re is enough to compensate for the construction cost of the second facade.8) Solar Heat weeThis point come to the issue of excessive of the incoming solar radioactivity above the comfort level especially in the summer time. So, in order to maintain solar heat gain under a standard design level is by preventing the heat from initially get in the space. Particularly for a highly full glazed building, normally an external shading devices are the most efficient mode of reducing solar heat gain. However, this external shading devices need to be cleaned frequently in order its can function effectively.In the other approach is to use the special glazing such as spectally selective glazing and where this glazing materials is able to respond differently to various wavelengths of solar energy or in other means is to permit visible light while rejecting unnecessary invisible infrared frequency heat. An ideal spectrally selective glazing permits only the art of the suns energy which is us eful for daylighting. other type of glass called electrochomic glass also able to improve the solar performance. The type of glass able to change its colour from clear to twilight(prenominal) using electrical current. The electrical current can be delirious in two ways, either by manually activated or by sensor reaction to the light intensity. In physic principle dark colour glass will reduce solar transmission into the building. Adversely when it is little sunlight, the glass will perform brightens in order to permit more suns ray into the building and minimized usage of hokey light.Both of the above mentioned materials is very practically apply for the full glazed double skin high rise building. Besides, the application of horizontal finesse can permit use of daylighting and at the same time still can achieve the exterior view and it is a more economic approaches.9) DSF Self Loading Transfer.This double skin facade (DSF) especially full glazed type, is unable to take its own l oad. Therefore, the dead load and imposed load of skins have to transferred to the adjacent structural wall and frames. Therefore, the design of structural wall and frames need to consider to carry the facade skins loading.10) Installation cover ChallengesHis installation process is difficult especially for full glazed double skins facade because it is tough to work with the increase of the building height. Also spiel near misses and possibility of the hazard of falling. Besides the wind gust is always a question of safety to its installer. Moreover the are only hold movements in the working place. Therefore, the design of open grates to put at floor by floor to act as the installer standing platform is advisable and can ease the installation process.ConclusionFrom the above, we have analysed the possible technical challenges of the double skin facade for this propose 10 storey of office. Therefore, the project design team need to consider that technical challenges during the ear lier wooden leg of design in order to come out a proper and efficient double skin facade building design in terms of aesthetical pleasing and maintenance capability.ReferencesConstruction Technology 5, Heriot-Watt UniversityTerri Meyer, Associate Professor, school of Architecture, University of Waterloowww.glassinbuilding.com/double_skin_facades