In: Civil Engineering
The A/E varies in the different approaches : traditional contract, Design build, and PMC approach
Traditional Contract:
The 'traditional' procurement route, sometimes referred to as 'design bid build' (or 'bid build' by contractors) remains the most commonly used method of procuring building works.
The client first appoints consultants to design the project in detail and then prepare tender documentation, including drawings, work schedules and bills of quantities. Contractors are then invited to submit tenders for the construction of the project, usually on a single-stage, competitive basis. This may be referred to as a 'traditional contract'. The contractor is not responsible for the design, other than temporary works, although some traditional contracts do provide for the contractor to design specific parts of the works.
Typically, the client retains the design consultants during the construction phase to prepare any additional design information that may be required, to review any designs that might be prepared by the contractor, and to inspect the works. Normally, one consultant (often, but not necessarily, the architect) will be appointed to administer the contract.
Traditional construction contracts are most commonly lump-sum contracts, however, measurement contracts and cost reimbursement contracts can also be used for ‘traditional’ projects where design and construction are separate, sequential activities.
This form of procurement is suitable for both experienced and inexperienced clients. Fully developing the design before tender gives the client certainty about design quality and cost, but it can be slower than other forms of contracting, and as the contractor is appointed only once the design is complete, they are not able to help improve the buildability and packaging of proposals as they develop.
It is considered to be a low risk method of contracting for the client, as the contractor takes the financial risk for construction. However, if design information is incomplete at tender, or if significant variations are required after the contractor has been appointed, the cost to the clientcan be significant. Because of this, and because of the separation of design and construction, traditional procurement can be seen as adversarial.
Design–build contractor:
The "design–builder" is often a general contractor, but in many cases a project is led by a design professional (architect, engineer, architectural technologist or other professional designers). Some design–build firms employ professionals from both the design and construction sector. Where the design–builder is a general contractor, the designers are typically retained directly by the contractor. Partnership or a joint venture between a design firm and a construction firm may be created on a long term basis or for one project only.
Until 1979, the AIA American Institute of Architects' code of ethics and professional conduct prohibited their members from providing construction services. However today many architects in the United States and elsewhere aspire to provide integrated design and construction services, and one approach towards this goal is design–build. The AIA has acknowledged that design–build is becoming one of the main approaches to construction. In 2003, the AIA endorsed "The architect's guide to design–build services",[3] which was written to help their members acting as design–build contractors. This publication gives guidance through the different phases of the process: design services, contracts, management, insurances, and finances.
Contractor-led design–build projects: the architect's role:
On contractor-led design–build projects, management is structured so that the owner works directly with a contractor who, in turn, coordinates subcontractors. Architects contribute to contractor-led design–build projects in one of several ways, with varying degrees of responsibility (where "A/E" in each diagram represents the architect/engineer):
Three models of contractor-led design–build
Architect-led design–build projects:
Architect-led design–build projects are those in which interdisciplinary teams of architects and building trades professionals collaborate in an agile management process, where design strategy and construction expertise are seamlessly integrated, and the architect, as owner-advocate, project-steward and team-leader, ensures high fidelity between project aims and outcomes. In architect-led design–build projects, the architect works directly with the owner (the client), acts as the designer and builder, coordinating a team of consultants, subcontractors and materials suppliers throughout the project lifecycle.
Architects lead design–build projects in several ways, with varying degrees of responsibility (where "A/E" in each diagram represents the architect/engineer):
Three models of architect-led design–build
Contracts:
A single set of integrated contracts combining design and construction responsibilities, rather than two discrete contracts for each, acknowledges the interdependence of the architects' and construction trades' project responsibilities, and reduces the likelihood of disputes.
PMC Approach:
PMC (PROJECT MANAJEMENT CONSULTANT) Is Usually the
manager of a project in behalf of the Company (Client). The PMC
handle the contracts issued by the Company to perform a project
such as EPC’s, Services, Training, interventory, logistics, etc...
This contractor is used to help the Company structure to handle
projects.