Cost Efficient Arch Lec 2 PDF

Cost Efficient Construction Lecture 2  Major Causes of High Building Costs Rising Cost of Construction & cost of materials Government charges Delayed approval of projects /building plans Lack of access to finance Outdated technologies Lack of necessary building...

Cost Efficient Construction Lecture 2  Major Causes of High Building Costs Rising Cost of Construction & cost of materials Government charges Delayed approval of projects /building plans Lack of access to finance Outdated technologies Lack of necessary building skills Lack of guidelines in selection of appropriate building packages Designs Materials Methods Equipment 2  Cost Reduction Methods Affordable housing is a term used to describe dwelling units whose total housing cost are deemed “Affordable” to a group of people within a specified income range. Affordable housing policies seek to house as many people as practical at the lowest cost, leading in the past to overcrowding. ▪ Various aspects for cost reduction ▪ Optimization of land use ▪ Functional design of buildings ▪ Optimum use of building materials ▪ Rationalization of specifications ▪ New construction materials and techniques 3 The need for cost effective techniques in design and construction of buildings Shelter problem( affordability) Homelessness Slum, Squatter and informal settlement Sustainability(social,economic and environmental) problems Energy Buildings are largest consumer of energy(50%) Resource/ material and water Economic/ money  Cost and Life cycle of building Cost effective living or cost effective building/housing? Life cycle costs INITIAL COST( MAKING OFBUILDING) OPERATION COST MAINTENANCE COST DISPOSAL AND DEMOLISHING COST Values ; Sustainability,inclusiveness,participation,innovation,integration,resilence,compactness,saftey  Initial Building Project cost comprises of: Cost of Land, Land Registration, Land survey Cost of Designing, Plan approval From surveying to plan approval Cost of developing Site Temporary electric, water connection Cost of Construction Structural, Electrical, Sanitary and other component constructions Miscellaneous costs Insurance The cost till occupancy Building Life cycle cost  What is cost efficient construction/ Building? Is it lowest first-cost structure that meets the program? Is it design with the lowest operation and maintenance costs? Is it building with the longest life span? Is it facility in which users are most productive? Is it building that offers the greatest return on investment? Cost efficient construction/ Building is a building which will minimize cost not only at initial stage but, also in the whole life cycle of building.  Possible factors for cost of building Shape, Size, Story heights, Total height, Fenestration and other building characteristics. users wishes, planning and Building Regulations requirements Site factors and aesthetic requirements Form of contract Period for completion, Structural form, Extent of Prefabrication and Standardization, Consideration of maintenance  Forms of contract 1. Lump-sum Contract 2. Cost Plus Fixed Fee Contract 3. Cost Plus Bid Fee Contract 4. Unit Price Contract 5. Design Build 6. Design bid-build  Lump-sum Contact ❑ Traditional method of contract ❑ The contractor offers to do the whole work for a total stipulated sum of money as shown in drawing and described by the specification. Cost Plus Fixed Fee Contract ❑ All cost for the work according to the specification is reimbursed by the owner to the contractor. ❑ Contractor is paid a fixed sum which represents the profits. ❑ The variation on the lump-sum fee is percentage fee wherein fees is established by percentage of total cost incurred by the contractor. ❑ Usually it is fixed as a sum.  Cost Plus Bid Fee Contract ❑ Owner invites proposal from qualified contractor in terms of past experience, performance….. ❑ All cost for the work according to the specification is reimbursed by the owner to the contractor. ❑ The bid fee is calculated on the basis of project scope. Unit Price Contract ❑ Based on the estimated quantities of the items involved in the work. ❑ The cost per unit item is given by the contactor and the estimated quantities of items are given by the owner. ❑ The total cost of work can only be calculated only after the completion of the work because measurement is made on the basis of work actually done.  Design Build ❑ It is a method to deliver a project in which the design and construction services are constructed by a single entity known as the design builder or design-build contractor. ❑ Design-build relies on a single point of responsibility contract and is used to minimize risks for the project owner and to reduce the delivery schedule by overlapping the design phase and construction phase of a project. Design Bid-Build ❑ It is a method to deliver a project in which the design and construction services are constructed by separate entity  Cost reduction methods ▪ Design-- Adopting optimum Design solutions- ▪ Materials cost-effective local materials, pre-cast, prefabricated , re-cycled materials , ▪ Technologies--Using technology to save on time , labor, space materials and money ▪ Management--Managing construction in most optimum manner ▪ Time-Using minimum Time for construction and completion of building/project ▪ Green- For optimal use of resource, water and energy  Cost reduction method through design Optimizes land and space utilization Optimizing climate, orientation Optimizing space planning Optimizing building envelope Optimizing structural layout Optimizing service design Morphological Factors and Cost  Plan shape Architectural form Structural layout/form “Architectural form/plan refers “Structural form is a building’s primarily to a building’s external primary or most visually dominant outline or shape, and to a lesser structural system mainly columns, degree references its internal walls, beams and slabs” organization and unifying principles”  Plan shape Shape determining factors 1) The client , site ,concept and design approach may determines/influences the building shape; 2) The building shape may determines a kind of building material; 3) Material may determines kind of construction. The shape affects the areas, perimeters and sizes of vertical components of the building. All these affects the cost of the whole building by affecting different components of building construction  Plan shape The shape of a building has an important effect on cost. As a general rule the simpler the shape of the building the lower will be its unit cost. As abuilding becomes longer and narrower or its outline is made more complicated and irregular accompanied by a higher unit cost. Shapes may be Regular or irregular Regular with different geometries  Plan shape Regular vs. Irregular The more complex and irregular the building shape is the more expensive it is to construct. Compared two buildings of rectangular and irregular shapes, each of which have the same floor area.  Plan shape Shape complexity Irregular shaped building where there is more external walls to enclose the same floor area, Irregular and Setting out Cost complex shapes Excavation cost have higher Drainage cost due to extra man holes costs and longer pipes High roof costs due to corners & material cutting wastages.  Constructability problems that come with complexity, plus increase in building elements like external walling with associated finishes like cladding, roofing, setting out costs, foundations, mechanical and electrical services among others.  Plan shape ❑ In building B where there is six per cent more external wall to enclose the same floor area, A Setting out costs are increased by about fifty percent, Excavation costs by about twenty per cent B Drainage Costs by approximately twenty-five per cent (two meters of additional 100mm drain and two extra manholes).  Plan shape Geometry A. High perimeter- to-floor ratio high unit construction High quantities of finishes and decorations like costs paints and plaster. Increased volume of external enclosing block walling Increased heat loss surface area. Change in foundation quantities Longer service and waste pipes Chances of extra doors & windows  Plan shape Plan shape and other Design variables The need to maintain a balance between various design criteria, cost, function and appearance. It is pointless for to submit cost-saving alternatives which could not function satisfactorily or which would or which would be aesthetically undesirable  Plan shape There are occasions when the site itself will dictate the form or shape of the building. The shape of a building may also be influenced by the manner in which it is going to be used. Plan shape has to bee seen integrally with other Design variables of cost  Plan shape Plan shape and other Design variables Although the simplest plan shape, that is a square building. will be the most economical to construct it would no always be a practicable proposition. Square structure would contain areas in the center of the building which would be deficient in natural lighting. Although a rectangular shaped building would be more expensive than a square one with the same floor area because of the smaller perimeter/floor area ratio, nevertheless practical or functional aspects, and possibly aesthetic ones in addition, may dictate the provision of a rectangular building. Effect of plan shape on different components of building construction  Plan shape Effect of plan shape ▪ foundation as a proportion of total on substructure building cost can vary from 8 to 18% and tend to decrease with increases in the number of storys. ▪ The nature of the soil determines type of foundation Setting out cost, foundation layout will be affected by plan shape Soil condition can cause quite different foundation cost for otherwise similar building.  ▪ Walls and partition with associated Effect of plan shape windows and doors constitute a major on walling item of expenditure of a building. In some housing, these components can accounts for about 20% from total cost Cost of walling affected by plan shape because plan shape affects the perimeter floor area ratio  Plan shape ▪ Plan shape affects the way columns Effect of plan shape arranged and the number of columns on Cost of frame ▪ The size of beams and columns and also structure the reinforcing of slab ▪ Irregular plan shape will have irregular shaped roof which will not easy for construction Effect of plan shape ▪ The higher the perimeter floor area ratio the on Cost of Roof higher the cost roof by increasing the structure amount of roof material and the work  Plan shape ▪ buildings with more complex shapes require Effect of Plan Shape an additional arrangement for acoustics, on Cost of Services lightning and ventilation, ▪ The more irregular shape and high perimeter to floor area ratio buildings the more the cost of services ▪ Irregular plan shape increase cost of Effect of plan shape finishing on finishing ▪ The higher the perimeter floor area ratio the higher the cost of finishing Thank you