huangyhg

design build
i feel stupid asking this question, but i have never worked on a design build project but have heard a lot about them. what exactly is a design build project?
what positive and negative experiences have others had with them? what are some things to expect out of the ordinary?
in the more usual cases, a project is made before construction can start. this serves well to the purposes of most owners or developers that from sound planning have time enough to verify -they and any other parties with the right- that the project is to meet any expected servicieabilities and mandatory standards. this way the project serves as a sound basis for the construction contract.
on the contrary, design-build projects appear in the construction industry as a way of delivering some constructions that are required in haste. in places like spain this rarely will be the case for works for private owners, since for them construction remains subject to the previous approval of the project, and final licence to build is usually (with some exceptions) deferred to the availability of construction design plans.
anywhere the project needs not to be defined partially or even at all from the beginning, design-build contracts ,where the builder offers a budget to care of both the design of the thing and its construction are feasible. for teams specialized in these ways and maybe specific typologies of construction this may result in quicker cycles of production and delivery and acceptable standerds precisely because they know beforehand (typically) much of the typology or at least of the critical elements of planning that permit efficient construction this way.
just away from the nicities of the concept,in some areas it is a licence for political heavies to make themselves cushy in the future at taxpayer's expense.
in theory it should work well but as all construction types there are also concerns. a concern is that quality and standards have to be adhered to and this can be an issue if a proper monitoring team is not in place from the inception.
design build is a method of project delivery that involves the owner hiring a contractor who in turn hires the designers. the contractor then builds the design made by his sub-contractors.
like all methods of project delivery there are some problems to be avoided. design-build works best if there can be a clear statement of requirement and this statement of requirement is unlikely to change. for example design build will work for municipal sub-division development. (given a street and lot layout, there are not a lot of changes possible in the design of the water and sewer.) it will also work for commercial space. design and build a store with xx square ft space, ceiling height of xxx ft, lighting levels of xxx etc.
design build does not work well if the owner does not know what he wants in the first place or if there are a lot of changes in the design or the statement of requirement during the process. if you think that change orders in traditional construction delivery methods are expensive, wait until you start working on design build change orders.
the biggest downfall for design build is in the area of quality control. the normal practice is for the designers to appoint inspectors who are responsible for the testing and on site quality control and have no financial interest in the outcome of these tests. in design build the designers are hired by the contractor who they are expected to control the quality of the final product built by the firm that has hired them. the conflict of interest is clear.
since quality problems can take some time to show up, the final product may initially look good but in 5 years not be quite as serviceable.
one design-build project that i heard about involved the construction of an elaborate mechanical process. the contractor in an effort to lower his costs used a wide variety of fabricators for the conveyors and other mechanical systems. the result was when they bought the required spare parts the owner had to buy a significant number of different bearings, rollers etc because there was no standardization in the plant.
design-build does work well for projects with a clearly defined statement of requirement. it can greatly speed up the process. there can be considerable cost savings since the management of the design is in the hands of construction people who know what things really cost.
some variations are bom and boom (build operate manage and build own operate manage). in these the contract is not for only the construction of the facility but also its on going operation. bom and boom could be used for say industrial effluent treatment. you would have a 20-year contract for xxx volume of effluent with stated properties. it also works for office space development. instead of the owner going out and building the office, they sign a long-term lease for office space built to their specifications.
like all other methods of project delivery, design build works best when everyone involved has a good understanding of the process, and of the results that they want to achieve. more important in design build than in design-bid-build is that the owner provides a well thought out statement of requirement that reflects the real needs.
rick kitson mba p.eng
construction project management
from conception to completion
we've worked on a number of design-build projects and they are ok. as stated above, there are pitfalls and concerns but generally these can be worked out.
there is also a more global view of db in that it does tend to push engineering into more of a commodity unless the contractor is intelligent enough to respect the engineering process and the professionalism it entails.
our projects generally are for a major governmental group who first hire an a/e firm to develop a conceptual set of documents. these are called "solicitation documents" and are roughly equal to about a 10% complete set of plans and specs.
each db team then takes these sol. docs. and develops the design (at risk) further to nail down a guaranteed maximum price - always given with assumptions spelled out.
the owner then selects the db team based on price and recommendations from his solicitation a/e firm.
the design then continues to 100%, many times with progressive reviews by the solicitation a/e and responses to the review comments by the db designers. once the final design is complete, the construction begins.
you, as an engineer working for a contractor, provide all the design efforts you usually do, with some of the depth of details in your plans not as deep as a bid set as you can more directly, and informally, communicate with your "teammate".
the solicitation a/e is still looking over your shoulder the whole time, protecting the interests of the owner, but not doing any of the design. they are not the engineer of record, you are.
rdkfff"> - excellent post. qa/qc is definitely the achilles heel of d/b projects. quality oriented firms, like kellogg/brown & root, bechtel, etc. can pull it off. but these firms began as engineering companies - not contractors. they have a different mind set.
and vadfff"> hit the nail on the head when he said,
"just away from the nicities of the concept,in some areas it is a licence for political heavies to make themselves cushy in the future at taxpayer'e expense."
absolutely! that's why i won't go along with design/build for public projects...
i worked on exclusively on db projects which are more often referred to as epc (engineering, procurement and construction) projects in my industry.
i would say db method is more suitable for large projects where different choices are available and many disciplines of engineering are involved. it is also automatic choice if a significant portion of the contract sum goes to procurement of plant items or services.
for example a sizeable power plant can take 10 years from conception to completion with db method of procurement. it will take at least 50% more time if structural engineer insist on the design is completed before a contractor is called, simply because he must wait for the electrical engineeer, the mechanical engineer, the c&i engineeer..... to finish their designs as well. while he is waiting he will find his design is continuously being invalidated by the changes from the other disciplines. he will have meetings to fight over the changes but have to concede to other disciplines when their changes are technically better for the project. the cycle can go on forever.
there are other practical reasons too. db contract is flexible and the client can choose different designs and different technologies from different countries. he can have the up to date technology and not stuck with the one offered by one design team.
personally i don't see economically how we can avoid db method of procurement for projects say over us$ 1 billions. it is not the ideal form preferred by the structural engineers but it is a fact of life of other disciplines.
with all due respect, we should look at db from all angles.
dear haynewp
i am coming from an engineering company. basically we are a design company, however during the last ten years we have concentrated on the construction works and most of the job we got up to now are based on design 鈥?build or turnkey or epcc (engineering, procurement, construction & commissioning) basis.
normally, in the design-build contract, the owner lets a single contract for both the design & the construction work of a project. firstly, we make the design and then perform the construction work (after design dwgs has been reviewed and approved by the owner). this method utilizes the experiences of the contractor in the design phase, which is very important to the success of the design. as my own experiences in the aspect of a designer & a site guy, sometime there are some inconsistencies & conflict in the design drawing as well as the lacking of site experiences from the designer. it costs time & money to correct the error.
in the situation of combining design & construction to a single company, it is clearly to realize that fewer of changes will arise during the construction phase due to designer mistake. if these kinds of changes occur in a traditional design-bid-built (or general contract) method they may cost a big money. in the owner鈥檚 point of view, there is an advantage that the potential for the owner being embroiled in disputes arising between the designer & the contractor is absolutely eliminated.
a thread i posted few months ago in this forum is a good example. in which i mentioned about our designer mistake when he indicated h244x175x7x11 mm as the pipe sleeper in the drawing instead of h294x200x8x12 mm of steel beam in the original calculation sheet. the result is our pipe sleepers are slightly overloaded. since this problem is our (the design 鈥?built contractor) internal affair, it is must be overcome by ourselves. actually, this problem is solved with out best capability and shortest time as well.
ordinarily, the design-built contractor shall maintain an in-door site design team at the site to correct & supplement the design product.
another advantage of the design-built is we can start the site work even the design work has not completely been done yet, so the project schedule can be reduced. this overlap of design & construction is referred to fast-tracking, as ishvaaag mentioned above, it means to deliver the project to the owner earlier than traditional design-bid-built approach. in an unstable & risky environment like ours nowadays, the shortest time of the project, the least of the risk.
this approach is particularly attractive when a project are large & technically complicated such as power plant, oil & gas plant or other complex industrial plant. the best thing the owner should do to the success of the project is his well prepared, clear & thorough the scope of project prior going to a formal design-built contract. in addition he can employ a consultancy service to help him in monitoring & managing the project or the design-build contractor.
in addition, in the design-bid-build method, we can realize that the competitive bidding process one contractor can use many tactics even unethical one to win over his competitor. during the construction phase, the concern for reducing incurred cost will be paramount in order to maintain the profit. this may lead to disputes with designer or between subcontractors or between the general contractor & the subcontractor. these kinds of things rarely occur in the design-build basis.
hope this help, sorry for my too long input.
some information i would like to add
the owner of a complex project normally develop his work like this:
1. hire a good engineering company to carry out the basic (conceptual) design & also feasibility research. this design product will be the frame of the project.
2. hire a good engineering company to be a pmc (project management & consultancy) contractor. the pmc play a role as an assistant of the owner. all of design, site work 鈥?must be reviewed & approved by the pmc. the owner hopes the know-how, in-house, experiences capability from the pmc to assure the project will be completed successfully & smoothly in aspect of qa/qc & cost.
3. hire a contractor to be an epcc contractor to carry out the detail design & equipment procurement, construction & commissioning works to finish the project. all of epcc contractor鈥檚 activities must be monitored & inspected by the owner鈥檚 inspector & the pmc. for example the contractor must invite the owner鈥檚 inspector to make a shop inspection before deliver equipment to the site.
generally, the specifications & procedures of a db contract are very strictly & carefully developed.
there are some ideas about a db project.
i worked in a design build industry, retaining walls for large building excavations. since only a few companies engage in this and a lot of the tieback methods are proprietary, this is usually stated as db. it also works well as soil conditions change, the design can be changed to suit without delays. such jobs usually prequalify the bidders. there needs to be a little trust in the contractor and let him do his job.
don't forget a lot of large and innovative bridge projects are done design-build. this is particularly true of precast segmental and cable-stayed designs.

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