It took only about an hour to slide each new structure into place. ODOT Photo and Video Services

It’s in the news every day: bridges failing, roadways in disrepair, infrastructure crumbling. While public agencies are waiting for funding, tens of thousands of bridge, roadway, highway, and other infrastructure projects across our country continue to queue up in the repair line.

The problem facing each project owner is the same: How to get these projects permitted, engineered, and constructed in the least amount of time, within budget, and with the highest degree of quality — all of this under the debilitating influence of an atrocious economy.

Traditionally, an owner would use the design-bid-build (DBB) methodology for project delivery. This involves an agreement with the engineer (procured using the quality-based selection process) to prepare a construction bid package, and a separate agreement with the contractor, normally selected by the lowest-priced construction bid; each having their individual delivery schedules.

The advantages of this delivery method include strict control over the project for the owner. It also promotes healthy competition for both the engineering and construction segments. However, there are disadvantages in DBB for the project owner, including:

• The design work must be 100 percent completed prior to construction advertisement; therefore, this method can take much longer to deliver the final constructed project.
• In today’s quickly changing and escalating materials market, the engineers’ cost estimate may be at risk, which could result in a higher-than-budgeted construction cost.
• Since the owner assumes the liability in DBB, he faces higher risks associated with contractor claims against design and constructability issues.

Trends
During the past 40 years, the association of a successful project delivery with the DBB method has steadily deteriorated and is more often associated with missed project schedules and budgets, and a decrease in quality of service and product.

According to a 1993 Engineering News-Record report, from 1986 to 1992, the total use of alternative delivery methods in the public and private sectors grew 172 percent. The Design-Build Institute of America has tracked traditional DBB and design-build (DB) project delivery data in the U.S. since 1985. Its data projections show that by 2015, the alternative delivery method for project execution will surpass the traditional DBB method.

Alternative delivery to the rescue
Today’s alternative delivery methods are founded on the original “master builder” model, which positioned one person (usually the engineer or architect) as director of the entire project, from design and engineering through construction.

At certain, less-civilized points in history, a successful master builder might gain a title, lands, or additional compensation for his work, whereas a failed project could encourage a more painful response from a project owner: “Off with his head!” As there was not much contingency that he could put into his contracts to mitigate the loss of his head, the master builder’s number one goal was to make sure the project was successful.

Fast-forward to the 21st century, and alternative delivery methods are becoming more attractive to today’s owner, due primarily to the cost and time savings involved.

A study by PinnacleOne, a construction consulting firm (now part of the Arcadis group), found that public agencies are searching for alternatives to DBB. When asked for the primary reason for an alternative procurement method, a majority (57 percent) of the agencies indicated reduced costs. Almost 40 percent of the participants cited the need to reduce the project schedules. And 53 percent of the agencies believed retaining a construction management advisor was effective in reducing their overall project risks.

Options
This acceptance to move into the alternative delivery market gives project owners a multitude of options, including public-private partnership (P3). This method involves a venture partnership between a government agency and one or more private-sector firms. Another option is the contractor manager/general contractor (CMGC) or contractor manager at-risk (CM@R) method. This involves a commitment by the construction manager to deliver a project to the owner within a guaranteed maximum price and eliminates a low-bid scenario, typically.

However, the most familiar and used alternative delivery method in the United States today is design-build (DB). Under the DB method, project engineering and construction are contracted under a single agreement with the owner. Typically, the owner’s agreement is with the contractor, and engineering is a sub-contract. This significantly minimizes the owner’s project risk and reduces the delivery schedule since the design and construction are performed concurrently.

The biggest benefit to an owner is the single source responsibility, wherein the owner is not required to coordinate or arbitrate between separate engineering or construction contracts, or to resolve budget and/or schedule conflicts. All responsibility for budget, schedule, and quality of workmanship, as well as conflicts between design and construction, are the contractor’s responsibility.

While DB has been used throughout the United States for decades, many public agencies are not well-versed in how to prepare a DB package that minimizes risk, yet delivers a quality project at a fixed price. Occasionally, owners prepare a DB package that lacks fully defined project specifications, allowing the final selection to be based on lowest price, not qualifications and project approach.

T.Y. Lin International (TYLI) has been providing DB services for more than 50 years — both domestically and abroad — for a variety of infrastructure projects varying in size and complexity. The following TYLI project serves as a case study and outlines how a team came together with a “project first” philosophy to deliver a highly successful project under the DB method. To date, this project has garnered six awards for the owner, the Oregon Department of Transportation (ODOT).

Case study
ODOT has used DB to deliver 16 of its projects under short development and construction schedules. Its success in DB comes from its well-defined procurement packages. ODOT selects its winning team via a submittal rating formula that places a higher value on qualifications and innovative approach than on price.

Steve Narkiewicz, ODOT’s project manager, said the agency structured its $46 million Elk Creek to Hardscrabble Creek (ECHC) project “as a design-build contract in order to generate the most creative solutions possible for a very technically difficult endeavor.” The winning team for this project was TYLI and the Slayden Construction Group (SCG).

Project: The ECHC project involved the replacement of five bridges along the OR-38 highway, including two structures that involved an innovative rapid bridge construction (RBC) technique: the new structures were built adjacent to the existing structures then skidded into place after removal of the existing structures.

Problem: A major challenge was to replace bridge structures without using long-duration partial or complete highway closures. The 50-foot distance from the tunnel at crossing No. 4 made installing a two-lane detour impossible without significant and expensive modification and expansion to the tunnel structure itself. The extreme topography surrounding crossing No. 3 (page 16) made landfall to the west of the creek, opposite the tunnel end, very difficult. A two-lane detour alignment to the south of the existing structure required a total detour bridge length twice as long as the replacement structure. An alignment toward the north required significant rock excavation and a cut slope extending well beyond available right-of-way.

Solution: In both cases, the solution was the use of RBC techniques. While not unknown within Oregon, RBC had never been employed for such a short closure period. RBC involves the complete construction of all bridge elements in and around the existing structure. Then, in a carefully orchestrated short highway closure period, demolition and removal of the existing structure take place.

Both crossing No. 3 and No. 4 were completed in this way, with only one weekend highway closure period each. Specialty construction subcontractor, Mammoet USA, provided the mechanical equipment required, and in partnership with the design team, their equipment was installed on temporary supports (engineered by TYLI). The equipment lifted the new superstructure and skid it into position after the existing bridge was demolished and removed. These crossings were the first to use RBC replacement techniques on Oregon state highways.

The creativity of the TYLI/SCG team continued with crossing No. 3. The bridge configuration required the use of short approach spans on a continuous three-span structure. Engineers familiar with this situation will immediately recognize the potential for abutment uplift at the ends of the structure and the requirement for a mechanical tie-down system.

Because of the system of installation, a unique solution to offset this uplift force partially was implemented: the entire structure was constructed such that the bridge would deform elastically as it was placed on its final supports. This prestressed a downward force into the abutment ends of the structure, partially offsetting the uplift force and resulted in a smaller, less complex hold-down device. This strategy also had the sustainable side effect of prestressing a compressive force into the entire bridge deck with the expectation of improved long-term performance.

Without detour structures, closing one lane of the elk creek tunnel bridges would have created six months of delays. By using rapid replacement, ODOT had to close the highway for only six days. ODOT Photo and Video Services

Conclusion
None of the ECHC project accomplishments could have been possible using a traditional DBB method. The team’s ability to engage in innovative solutions was made possible by the DB format, which enabled the engineers, the contractor, and the owner to mobilize quickly to solve the design and construction issues without impacting the schedule or the environmentally sensitive areas.

Proactive team interaction resulted in this project being completed on time and within budget, resulting in industry recognition, awards, and more importantly, enthusiastic approval by the communities it serves.

The ECHC project shows that DB is an alternative delivery method that provides an owner with time savings, and single-source, turn-key project construction, while allowing the contractor and engineering team to bring innovation to complex projects.

Design-build is the right choice now for project owners. By adding this tool to his toolbox, an owner can get projects constructed, even in this poor economy, and take advantage of the time and cost savings this burgeoning method of project delivery offers.

Patrick Waterman, P.E., is a director of business development for T.Y. Lin International, and he can be contacted at patrick.waterman@tylin.com. Alice Brown is an associate and the Northwest district marketing manager for T.Y. Lin International, and can be contacted at abrown@tylin.com.