Estimating and Tendering methods for Construction WorK

TRADITIONAL METHOD

• The traditional structure for project procurement is where the employer takes his scheme to an advanced stage with his professional team before appointing a contractor.
• The consultant’s role is seen as an independent one.

The designer is employed to advise the client and design the work

A quantity surveyor gives guidance on design costs and budgets,prepare bills of quantities, check tenders, prepare interim valuations and advises on the value of variations

• A consultant structural engineers might be employed either by the client, or his advisers, to design the specialist parts of the project.
• many major building owners and developers make use of in-house project managers to carry out all the design and financial control of the project.

Project management is therefore seen as a management tool and not a procurement method.

DESIGN AND BUILD METHOD

• The design and build arrangement is an attractive option for clients. because the contractor accepts the responsibility for designing and constructing.
• The benefits include: single-point responsibility, prices which reflect more closely the final cost to the leading to early completion.
• The design and build arrangement is an attractive option for clients. because the contractor accepts the responsibility for designing and constructing.
• The benefits include: single-point responsibility, prices which reflect more closely the final cost to the leading to early completion.
• There is a contractual arrangement known as‘Turnkey’ this allows a client to procure from a single contractor all the requirements of a scheme in the shortest possible time.

the agreement will often include getting the land short-and long-term finance, fitting out , recruitment and training of personnel

DESIGN AND BUILD SYSTEM

• A design and build contractor may commission design and cost services from outside consultants or can employ a design team from within their own organization.
• At tender stage the employer will introduce some competition, either open or selective tendering, which is followed by clarification of the agreement and negotiation.
• The number of contractors invited to submit tenders in the form of Contractor’s Proposals should be limited to three or four firms to reduce the high tendering costs.
• A contractor might make a client’s brief fit his own preferred solution; the long-term life of a building might be overlooked and if the brief is vague, the client could pay an inflated price or take possession of an inferior building.
• A client may not realize the importance of independent professional advice. The cost of abortive designs and tendering is a heavy burden on contractors’ overheads and eventually the costs will be passed on to clients.
• The management contractor is appointed to work with the professional team, to con-tribute his construction expertise to the design and later to manage the specialist ‘package’ or ‘works’ contractors.
• He is responsible for the smooth running of the work on site so that the contract can be finished within time and cost.
• One development has been a combination of design and build and management contracting whereby the contractor produces a design and guaranteed maximum price, and the work is later assigned to a number of major package
• A management contractor is selected using the following criteria:
• Experience of management contracting.
• Quality and experience of project staff.
• Fee.
• Programme and method statement.
• The consultants, grouped under the title of ‘the professional team’, prepare the
• drawings, specifications and bills of quantities for the various works contracts.
• The Architect (or Contract Administrator) leads the Professional Team and issues
• instructions to the management contractor on behalf of the employer.
• The management contractor’s role is in coordinating the design and preparing cost studies at the pre-construction stage.

Clients are attracted to management contracting for the following reasons:

• Construction can start before design is complete, and design can be changed during the construction phase;
• Construction expertise is available to improve on the design;
• Better coordination of specialist contractors through detailed planning of work packages and common facilities;
• A contractor’s knowledge of construction costs is used to maintain tight budgetary control.
• The specialists often carry the burden of late changes to drawings and specifications which are more common when design development takes place during construction.
• The client cannot be sure of the final cost and will carry more risk. This is because the management contractor can pass on all the costs incurred for each trade, site staff and site facilities.
• some clients would not want to deal directly with sub-contractors or be involved in every problem of time and cost that could arise.
• At tender stage, each specialist contractor receives specifications, drawings, method statements, and details of the scope of works from which each estimator can prepare his own bills of quantity.
• . All risks associated with the preparation of bills of quantity which must include all work needed to complete the package whether shown clearly on the drawing or not.
• In some cases contractors must assess reinforcement quantities, for example, before the reinforcement is designed;
• The need to complete elements of the design to the satisfaction of the architect;
• Payment retention's may be kept for up to 12 months after the completion of the whole project;
• Complex warranties for all contractors with design responsibilities.