Design Principles And Application For Construction Build Environment Construction Essay
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Construction planning is a very important and challenging activity in the management and execution of construction projects. It involves the choice of technology, the definition of work tasks, the estimation of the required resources and durations for individual tasks, and the identification of any interactions among the different work tasks. A good construction plan is the basis for developing the budget and the schedule for work. Developing the construction plan is a critical task in the management of construction, even if the plan is not written or otherwise formally recorded. In addition to these technical aspects of construction planning, it may also be necessary to make organizational decisions about the relationships between project participants and even which organizations to include in a project. For example, the extent to which sub-contractors will be used on a project is often determined during construction planning. Essential aspects of construction planning include the generation of required activities, analysis of the implications of these activities, and choice among the various alternative means of performing activities. Construction planners face the normative problem of choosing the best among numerous alternative plans. A planner must imagine the final facility as described in the plans and specifications. In developing a construction plan, it is common to adopt a primary emphasis on either cost control. Some projects are primarily divided into expense categories with associated costs. In these cases, construction planning is cost or expense oriented. Within the categories of expenditure, a distinction is made between costs incurred directly in the performance of an activity and indirectly for the accomplishment of the project. For example, borrowing expenses for project financing and overhead items are commonly treated as indirect costs. For other projects, scheduling of work activities over time is critical and is emphasized in the planning process. In this case, the planner insures that the proper precedencies among activities are maintained and that efficient scheduling of the available resources prevails. Traditional scheduling procedures emphasize the maintenance of task precedencies (resulting in critical path scheduling procedures) or efficient use of resources over time (resulting in job shop scheduling procedures). Finally, most complex projects require consideration of both cost and scheduling over time, so that planning, monitoring and record keeping must consider both dimensions. In these cases, the integration of schedule and budget information is a major concern. Without planning very difficult to see the successful conclusion of any project. Planning is also important in order to deal with construction risks and develop save working methods. Planning is the process needed to make everything happen in the proper order to get the work approved, accomplished and paid for. Arranging funding, scheduling the various tasks, and arranging the needed approvals are a few of the tasks that must be accomplished for the successful completion of a project. These planning steps are preliminary to design. (Planning and design, 2010)The reason for planning could be relieve a control during the project and review the progress or take action when necessary to correct the situation. At the early stage of a project is essential for the client team to have a program in order to aid control. From a financial planning point of view, the form of contract is important because payment terms and payment periods are specified and the retention percentage is stated. During the project, the contract explains procedures for dealing with delay, how contract variations are to be dealt with and what entitlements the parties will receive for damages occurring from delays. Construction planning is not an activity which is restricted to the period after the award of a contract for construction. It should be an essential activity during the facility design. Also, if problems arise during construction, re-planning is required. As in the development of appropriate alternatives for facility design, choices of appropriate technology and methods for construction are often ill-structured yet critical ingredients in the success of the project. For example, a decision whether to pump or to transport concrete in buckets will directly affect the cost and duration of tasks involved in building construction. A decision between these two alternatives should consider the relative costs, reliabilities, and availability of equipment for the two transport methods. Unfortunately, the exact implications of different methods depend upon numerous considerations for which information may be sketchy during the planning phase, such as the experience and expertise of workers or the particular underground condition at a site. In selecting among alternative methods and technologies, it may be necessary to formulate a number of construction plans based on alternative methods or assumptions. Once the full plan is available, then the cost, time and reliability impacts of the alternative approaches can be reviewed. This examination of several alternatives is often made explicit in bidding competitions in which several alternative designs may be proposed or value engineering for alternative construction methods may be permitted. In this case, potential constructors may wish to prepare plans for each alternative design using the suggested construction method as well as to prepare plans for alternative construction methods which would be proposed as part of the value engineering process. At the same time that the choice of technology and general method are considered, a parallel step in the planning process is to define the various work tasks that must be accomplished. These work tasks represent the necessary framework to permit scheduling of construction activities, along with estimating the resources required by the individual work tasks and any necessary precedencies or required sequence among the tasks. The planning process for construction projects consists of three stages that take place between the moment in which a planner starts the plan for the construction of a facility to the moment in which the evaluation of the final output of the construction process is finished.
The estimate stage involves the development of a cost and duration estimate for the construction of a facility as part of the proposal of a contractor to an owner. It is the stage in which assumptions of resource commitment to the necessary activities to build the facility are made by a planner. A careful and thorough analysis of different conditions imposed by the construction project design and by site characteristics are taken into consideration to determine the best estimate. The success of a contractor depends upon this estimate, not only to obtain a job but also to construct the facility with the highest profit. The planner has to look for the time-cost combination that will allow the contractor to be successful in his commitment. The result of a high estimate would be to lose the job, and the result of a low estimate could be to win the job, but to lose money in the construction process. When changes are done, they should improve the estimate, taking into account not only present effects, but also future outcomes of succeeding activities. It is very seldom the case in which the output of the construction process exactly echoes the estimate offered to the owner.
In the monitoring and control stage of the construction process, the construction manager has to keep constant track of both activities' durations and ongoing costs. It is misleading to think that if the construction of the facility is on schedule or ahead of schedule, the cost will also be on the estimate or below the estimate, especially if several changes are made. Constant evaluation is necessary until the construction of the facility is complete. When work is finished in the construction process, and information about it is provided to the planner, the third stage of the planning process can begin.
The evaluation stage is the one in which results of the construction process are matched against the estimate. A planner deals with this uncertainty during the estimate stage. Only when the outcome of the construction process is known is he/she able to evaluate the validity of the estimate. It is in this last stage of the planning process that he or she determines if the assumptions were correct. If they were not or if new constraints emerge, he/she should introduce
Design is a process of creating the description of a new facility, usually represented by detailed plans and specifications; construction planning is a process of identifying activities and resources required to make the design a physical reality. Construction is the implementation of a design envisioned by architects and engineers. In both design and construction, numerous operational tasks must be performed with a variety of precedence and other relationships among the different tasks. The planning for design can proceed almost simultaneously, examining various alternatives which are desirable from both viewpoints and thus eliminating the necessity of extensive revisions under the guise of value engineering. Furthermore, the review of designs with regard to their constructability can be carried out as the project progresses from planning to design. For example, if the sequence of assembly of a structure and the critical loadings on the partially assembled structure during construction are carefully considered as a part of the overall structural design, the impacts of the design on construction falsework and on assembly details can be anticipated. If the design professionals are expected to assume such responsibilities, they must be rewarded for sharing the risks as well as for undertaking these additional tasks. Similarly, when construction contractors are expected to take over the responsibilities of engineers, such as devising a very elaborate scheme to erect an unconventional structure, they too must be rewarded accordingly. As long as the owner does not assume the responsibility for resolving this risk-reward dilemma, the concept of a truly integrated system for design and construction cannot be realized. Innovative design concepts must be tested for technological feasibility. Three levels of technology are of special concern: technological requirements for operation or production, design resources and construction technology. The first refers to the new technologies that may be introduced in a facility which is used for a certain type of production such as chemical processing or nuclear power generation. The second refers to the design capabilities that are available to the designers, such as new computational methods or new materials. The third refers to new technologies which can be adopted to construct the facility, such as new equipment or new construction methods. Construction planning should be a major concern in the development of facility designs, in the preparation of cost estimates, and in forming bids by contractors.(The design process,2010)
All these considerations can simply be categorized as the case may be, under Design, Equipment and Installation. This paper is primarily assigned to talk on the second category that is, appropriate use of materials and equipment in building services. Even then, it is not possible in this brief talk to treat in the required degree of details, the large number of materials and equipment used in the several building services. Rather, what is attempted is to present a framework for an understanding of the general principles involved in taking decisions regarding the choice or specification of a service system and the associated equipment.
Responsibly managing waste on a construction jobsite is a vital component of sustainable building. In this context, managing waste means minimizing the construction waste or demolition debris (C&D) that leaves the jobsite for landfill disposal. Waste management should be an integral part of a project's development. Each of the principal project participants-the Owner, their Architectural and Engineering (A/E) services (or Construction Management consultant), the Contractor, and Subcontractors-will engage in waste management to some degree throughout the project. Initially, the Owner and their A/E must establish waste reduction goals and define what levels of diversion are achievable and reasonable under the project's conditions. The Contractor is responsible for the means, methods, techniques, sequences, and procedures of construction, which include waste disposal methods. However, the A/E's design team can contribute to waste reduction in several ways. These include:
Because working hours in offices are principally the hours of daylight, there are considerable advantages in maximizing an office buildings potential use of daylight. The major difficulty in achieving this goal is the unequal distribution of daylight levels. I luminance levels fall away sharply as room depth increases away from the windows, making the back of offices having insufficient light and also the front of the offices near to the windows very bright and a source of glare. Daylight is the medium to which the human eye is biologically adapted. Artificial lighting used in offices can account for up to 50% of primary energy use, but because there is a close correlation between office working hours and hours of daylight availability, the efficient use of daylight can lead to a reduction of between 35% and 75% of the amount of lighting power which is consumed if controls that automatically dims lights according to light levels outdoors are used.
The energy consumption profile of supermarkets is a little different from other types of retail building. Some quite basic forms of enclosure such as do-it-yourself stores have characteristics more akin to those of a warehouse then those of shops in a mall. Consequently, by far the largest proportion of their energy cost is due to electricity used for lightning, but because they tend to have high ceilings and thus a large volume to heat, fossil fuel space heating and domestic hot water are responsible for a fair population of the total. This proportion diminishes for other non-food shops where mechanical ventilation and possibly air-conditioning and lifts increase the relative amount of electricity that is consumed.
Another company that is very active in this area is MF1. Since 1994 the company which is total has about 500 stores, has used a variety of measures aimed to cut its carbon emissions 50%. A building management system, which automatically controls the store heating and lightning levels, was introduced at a cost of £800,000-expenditure that was repaid by energy savings within 12 months. A typical innovation was the fitting of self-dimming lights within a 50,000 m2 warehouse that paid for itself within 18 months. Having achieved rigorous control over energy bills, the company then moved on to the replacement of conventional power sources by renewable energy. Fifty outlets are being powered from renewable energy obtained from an independent supplier who sells electricity obtained from wind farms and gas from landfill.
During initial strategic planning, the extent of heat loss from factory buildings can be controlled by careful site layout. For example, heat loss will be reduced if loading doors are designed to face away from the prevailing wind, and particularly if the doors allow easy operation so that they are likely to be kept open for shorter lengths of time. Factory buildings can be grouped together to reduce the extent of heat loss (is perhaps at the expense of future flexibility for expansion), and of course uninsulated party walls between units will lose heat if the factory next door is unheated. Shelter belts of trees, or moving earth to form mounds around the site, can reduce wind speeds and thereby the rate of heat loss, since infiltration from the building will be generally dependent on the ambient wind speed and direction. The elevation of the roof is important because a shallow slope will enclose a smaller volume needing heat, provided that a higher roof isn't required either by the production process, or the need for tall storage racking. (A. Dye).
There is an extensive literature concerning the environmental impact of building materials, construction activities and the use (and misuse) of buildings during the life time. We know that we must do more to respect our planet and build in a way that has a positive impact on our environment. Unfortunately the reality is that we could do a lot more in this regard. The choices made by patties to the design and construction process will colour the environmental impact of a building during its construction, use and eventual recycling, and so care should be taken to consider the whole life of the building. From a construction perspective consideration should be given to the method of construction, maintenance and repair, future adaptability of the structure and there cycling of materials as and when the building is demolished or substantially remodeled. This is particularly important at the detailing and specification stage when materials and components are selected. Adopting the open building concept may be one way forward, but there are many ways in which we can improve the relationship between our artificial environment and our nature one. For example, detailing buildings so as to reduce unnecessary waste during production not only helps to reduce land fill. It also saves time and money. (Barry's).
In recent years, technological innovation in design have resulted in significant changes in construction costs. Computer-aids have improved capabilities for generating quality designs as well as reducing the time required to produce alternative designs. The most dramatic new technology applied to construction has been the Internet and its private, corporate Intranet versions. The Internet is widely used as a means to foster collaboration among professionals on a project, to communicate for bids and results, and to procure necessary goods and services. Real time video from specific construction sites is widely used to illustrate construction progress to interested parties. The result has been more effective collaboration, communication and procurement. Design professionals and construction contractors who have not adapted to changing technologies have been forced out of the mainstream of design and construction activities.
Describe the roles, responsibilities and obligations (including liability for health, safety and welfare) of all parties involved in construction projects:
At the early stage of strategic planning for a capital project, an owner often seeks the services of financial planning consultants such as certified public accounting (CPA) firms to evaluate the economic and financial feasibility of the constructed facility, particularly with respect to various provisions of federal, state and local tax laws which may affect the investment decision. Investment banks may also be consulted on various options for financing the facility in order to analyze their long-term effects on the financial health of the owner organization.
In the project life cycle, the most influential factors affecting the outcome of the project often reside at the early stages. At this point, decisions should be based on competent economic evaluation with due consideration for adequate financing, the prevalent social and regulatory environment, and technological considerations. Architects and engineers might specialize in planning, in construction field management, or in operation, but as project managers, they must have some familiarity with all such aspects in order to understand properly their role and be able to make competent decisions. Engineers often spend as much or more time on planning, management and other economic or social problems as on the traditional engineering design and analysis problems which form the core of most educational programs. It is upon the ability of engineers to tackle all such problems that their performance will ultimately be judged. The greatest stumbling block to effective management in construction is the inertia and historic divisions among planners, designers and constructors. While technical competence in design and innovation remains the foundation of engineering practice, the social, economic and organizational factors that are pervasive in influencing the success and failure of construction projects must also be dealt with effectively by design and construction organizations. Of course, engineers are not expected to know every detail of management techniques, but they must be knowledgeable enough to anticipate the problems of management so that they can work harmoniously with professionals in related fields to overcome the inertia and historic divisions. The owners have much at stake in selecting a competent project manager and in providing her or him with the authority to assume responsibility at various stages of the project regardless of the types of contractual agreements for implementing the project. Of course, the project manager must also possess the leadership quality and the ability to handle effectively intricate interpersonal relationships within an organization. The ultimate test of the education and experience of a project manager for construction lies in her or his ability to apply fundamental principles to solving problems in the new and unfamiliar situations which have become the hallmarks of the changing environment in the construction industry.
Prior to construction. The manner in which a building is designed and detailed, i.e. the materials selected and their intended relationship to one another, will have a significant bearing on the safety of operations during construction. See www.safetyindesign.org
During construction. Easy of constructability will have a bearing safety during production. Off-site manufacturing offers the potential of a safer environment, primarily because the factory setting is more stable and easier to control than the constantly changing construction site.However, the way in which work is organized and attitude of workers towards safety will also have significant bearing on accident prevention.
During use. Routine maintenance and repair is carried out throughout the life of a building. Even relatively simple task such as changing a light bulb can become a potential hazard if the light fitting is difficult to access. Elements of the building with short service life must be accessed safely.
Demolition and disassembly. Attention must be given to the workers who at some time in the future will be charged with disassembling the building. Method statements and guidance on a suitable and safe disassembly strategy are required.
Project is conceived to meet market demands or needs in a timely fashion. Various possibilities may be considered in the conceptual planning stage, and the technological and economic feasibility of each alternative will be assessed and compared in order to select the best possible project. The financing schemes for the proposed alternatives must also be examined, and the project will be programmed with respect to the timing for its completion and for available cash flows. After the scope of the project is clearly defined, detailed engineering design will provide the blueprint for construction, and the definitive cost estimate will serve as the baseline for cost control. In the procurement and construction stage, the delivery of materials and the erection of the project on site must be carefully planned and controlled. After the construction is completed, there is usually a brief period of start-up or shake-down of the constructed facility when it is first occupied. Finally, the management of the facility is turned over to the owner for full occupancy until the facility lives out its useful life and is designated for demolition or conversion.
Napier,T.(2010),Construction Waste Management available at www.wbdg.org accessed 20/11/2010
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