Design-build (or design/build, and abbreviated D-B or D/B accordingly) is a project delivery system used in the construction industry. It is a method to deliver a project in which the design and construction services are contracted by a single entity known as the design-builder or design-build contractor. In contrast to "design-bid-build" (or "design-tender"), 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. "DB with its single point responsibility carries the clearest contractual remedies for the clients because the DB contractor will be responsible for all of the work on the project, regardless of the nature of the fault".
The traditional approach for construction projects consists of the appointment of a designer on one side, and the appointment of a contractor on the other side. The design-build procurement route changes the traditional sequence of work. It answers the client's wishes for a single point of responsibility in an attempt to reduce risks and overall costs. It is now commonly used in many countries and forms of contracts are widely available.
Design-build is sometimes compared to the "master builder" approach, one of the oldest forms of construction procedure. Comparing design-build to the traditional method of procurement, the authors of Design-build Contracting Handbook noted that: "from a historical perspective the so-called traditional approach is actually a very recent concept, only being in use approximately 150 years. In contrast, the design-build concept--also known as the "master builder" concept--has been reported as being in use for over four millennia."
Although the Design-Build Institute of America (DBIA) takes the position that design-build can be led by a contractor, a designer, a developer or a joint venture, as long as a design-build entity holds a single contract for both design and construction, some architects have suggested that architect-led design-build is a specific approach to design-build.
Design-build plays important role in pedagogy, both at universities and in independently organised events such as Rural Studio or ArchiCamp.
Maps, Directions, and Place Reviews
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", 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.
Design And Build Services Video
Design-build institutes
In 1993, the Design-Build Institute of America (DBIA) was formed. Its membership is composed of design and construction industry professionals as well as project owners. DBIA promotes the value of design-build project delivery and teaches the effective integration of design and construction services to ensure success for owners and design and construction practitioners. The Design-Build Institute of America is an organization that defines, teaches and promotes best practices in design-build.
The Canadian Design-Build Institute (CDBI) describes itself as "The recognized voice of Design-Build practitioners in Canada, promoting and enhancing the proper utilization of Design-Build method of procurement and contracting"
Debate on the merits of design-build vs. design-bid-build
The rise of design-build project delivery has threatened the traditional hierarchies and silos of the design and construction industry. As a result, a debate has emerged over the value of design-build as a method of project delivery.
Critics of the design-build approach claim that design-build limits the clients' involvement in the design and allege that contractors often make design decisions outside their area of expertise. They also suggest that a designer--rather than a construction professional--is a better advocate for the client or project owner and/or that by representing different perspectives and remaining in their separate spheres, designers and builders ultimately create better buildings.
Proponents of design-build counter that design-build saves time and money for the owner, while providing the opportunity to achieve innovation in the delivered facility. They note that value is added because design-build brings value engineering into the design process at the onset of a project. Design-build allows the contractor, engineers and specialty trade contractors (subcontractors) to propose best-value solutions for various construction elements before the design is complete. Design-build brings all members of a project team together early in the process to identify and address issues of cost, schedule and constructability. Proponents suggest that as a result, design-build alleviates conflict between architects and contractors and reduces owner risk for design errors. They argue that once design is finalized and construction begins, the greatest opportunity to achieve cost savings has already been lost, and the potential for design errors is greater, leading to change orders that create cost growth and schedule delays. Proponents note that design-build allows owners to avoid being placed directly between the architect/engineer and the contractor. Under design-bid-build, the owner takes on significant risks because of that position. Design-build places the responsibility for design errors and omissions on the design-builder, relieving the owner of major legal and managerial responsibilities. The burden for these costs and associated risks are transferred to the design-build team.
The cost and schedule reduction and decreased litigation associated with design-build project delivery have been demonstrated repeatedly. Researches on Selecting Project Delivery Systems by Victor Sanvido and Mark Konchar of Pennsylvania State University found that design-build projects are delivered 33.5% faster than projects that are designed and built under separate contracts (design-bid-build). Sanvido and Konchar also showed that design-build projects are constructed 12% faster* and have a unit cost that is 6.1% lower than design-bid-build projects. Similar cost and time savings were found in a comparison study of design-build, and design-bid-build for the water/wastewater construction industry, a peer-reviewed paper authored by Smith Culp Consulting that will be published in July 2011 by the American Society of Civil Engineers. A benchmarking and claims study by Victor O. Schinnerer, one of the world's largest firms underwriting professional liability and specialty insurance programs, found that, from 1995-2004, only 1.3% of claims against A/E firms were made by design-build contractors.
Growth of design-build method
A 2011 study analyzing the design-build project delivery method in the United States shows design-build was used on about 40 percent of non-residential construction projects in 2010, a ten percent increase since 2005. The study was commissioned by the Design-Build Institute of America (DBIA) and was completed by RSMeans Reed Construction Data Market Intelligence. Lego
A study from the US Department of Transportation claims that: "Design-build delivery has been steadily increasing in the U.S. public building sector for more than 10 years, but it is still termed experimental in transportation. To date, under Special Experimental Project 14 (SEP-14) the FHWA has approved the use of design-build in more than 150 projects, representing just over half of the States. The European countries visited have used design-build delivery for a longer time than the United States and provided the scan team with many valuable insights. The primary lessons learned on this scan tour relate to the types of projects utilizing design-build, the use of best-value selection, percentage of design in the solicitation, design and construction administration, third-party risks, the use of warranties, and the addition of maintenance and operation to design-build contracts."
Criticisms of design-build
During the design-build procedure, the contractor is deciding on design issues as well as issues related to cost, profits and time exigencies. Whilst the traditional method of construction procurement dissociates the designers from the contractors' interests, design-build does not. On these grounds it is considered that the design-build procedure is poorly adapted to projects that require complex designs for technical, programmatic or aesthetic purposes. If the designer/architect is 'kept' by the construction company, they probably will never push the envelope as to what might be possible. A notable design-build project that received significant criticism, not only for excessive cost but for environmental issues, was the Belmont Learning Center. The scandal involved alleged contaminated soil that caused significant delays and massive cost overruns. In Los Angeles, District Attorney Steve Cooley, who investigated the Los Angeles Unified School District's Belmont project, produced a final investigative report, released March 2003. This report concluded that the design-build process caused a number of issues relating to the Belmont scandal:
- Design-build does not make use of competitive bidding where prospective builders bid on the same design.
- Criteria to select contractor are subjective and difficult to evaluate and to justify later.
- The design and price selected arouses public suspicion, true or not.
- This can lead to loss of public confidence.
- The design brief is subject to different interpretations from both the client and contractor, creating a conflict of interest.
It concluded the "design-build" approach and "mixed-use concept" together caused controversy, uncertainty, and complexity of the Belmont project which helped increase the potential for project failure.
While the Belmont investigation cleared the Los Angeles Unified School District of any criminal wrongdoing, the task force recommends strict oversight, including written protocols, a vigorous Office of the Inspector General, and other recommendations if it decides to continue to use the design-build approach.
During the period in question, the ex-Superintendent of LAUSD, Ramon C. Cortines, working with the LAUSD Board of Education, whose president is Monica Garcia, actively tried to cut the Office of Inspector General by 75% (compromising on 25%) and subsequently removed the Inspector General Jerry Thornton after he produced critical audits that showed misuse of construction funds.
Source of the article : Wikipedia
EmoticonEmoticon