The state of South Carolina faced a challenge. The two cantilever truss bridges that spanned the Cooper River and connected Charleston and Mount Pleasant, SC, needed to be replaced. The two bridges, which were constructed in the 1960s, played a key role in the area’s infrastructure. Without them, Mount Pleasant lacked a direct route to the city of Charleston, which had the only hospital in the area with a trauma center. The bridges were also a major economic thoroughfare between the two communities.
Time had taken its toll on the bridges’ integrity, and they had not been designed to carry the volume of traffic that now traveled over the Cooper River. One of the two bridges suffered from serious deterioration, which meant that large trucks and other heavy vehicles could not use it, and neither bridge had emergency lanes, shoulders, or medians to divide northbound and southbound lanes, aside from some temporary barriers that were installed in 2002. In addition, the bridges’ design restricted the ability of engineers to make the channel beneath them wider and deeper, and lacked the height to clear the largest shipping vessels. These factors limited the potential growth of the Port of Charleston, the fourth biggest container port in the US.
By the late 1990s, the state, with the assistance of Federal funding, had budgeted more than $500 million to build a new bridge. And like all public works projects of this sort, there was a great deal of pressure to ensure that the bridge be delivered on time and within the allocated budget.
The state opted for a design-build approach and contracted with a joint venture for both the design and construction. That joint venture was made up of Tidewater Skanska, Inc., which led the team, and Flatiron Constructors Inc.
The decision to take a design-build approach turned out well for the state and for Tidewater Skanska. The firm delivered the finished bridge, which is the longest cable-stay suspension bridge in the Western Hemisphere, a full year ahead of schedule, and did so in the face of some serious design and construction challenges.
On the design side, engineers knew that the bridge would span a shipping lane that has a history of ship collisions with previous bridges. The design had to be able to withstand a major accident. In addition, the river is located in an area that is prone to strong storms and hurricanes. In 1989, for instance, Hurricane Hugo, one of the most powerful hurricanes ever to hit the United States, devastated the area. The finished bridge would need to be able to withstand storms stronger then Hugo to meet expectations. A lesser known threat is the potential for seismic activity. Though there has not been a major quake in recent times, the Port of Charleston is a geologically active region that has historically experienced strong earthquakes. Engineers would need to design a structure that could withstand a strong earthquake. Finally, given Charleston’s reputation as one of America’s most beautiful cities, the bridge had to meet high aesthetic standards. For instance, the design originally called for a lighted display on top of each of the towers, but this element was later eliminated after consulting with the community.
Construction also posed challenges. Part of the construction site was adjacent to a residential area, so crews could do very little work at night and construction noise had to be kept to a minimum. And the size and complexity of the proposed Cooper River Bridge, whose formal name would be the Arthur Ravenel, Jr. Bridge, created challenges of its own.
Initial design requirements called for either two separate four-lane span bridges or a single eight-lane span bridge. The first four lanes were to be delivered in 2005, 44 months after signing the contract, with the final four lanes coming in 16 months later in 2006. The joint venture opted for the more difficult, single eight-lane span, a 570-foot-high suspension bridge that would run 2.5 miles long. It would carry eight traffic lanes plus a 12-foot-wide pedestrian and bicycle path.
The joint venture delivered the first four lanes on-time. The remaining lanes were delivered 14 months early.
To tackle a program of this magnitude, Wade Watson, vice president of Tidewater Skanska, decided to divide the program into five distinct projects in order to enable better control over each project and to facilitate the use of specialized talent. These projects were the span itself, two high-level approaches and two interchanges. In turn, as the program manager, Watson needed to oversee coordination of the five separate projects into a seamless whole to deliver the final bridge. To do this, he needed to institute best practices across each project. These best practices included: standardized collaboration procedures, a rigorous change management procedure, centralized scheduling, and the creation of key health indicators across all projects to compare apples to apples. In so doing, he was able to manage a master plan that kept everything synchronized.
Keeping the master schedule running smoothly was of paramount importance. A delay in the interchange could mean a delay in the high-level approach, which would mean a delay in the cable stay. And because the Cooper River Bridge took a design-build approach, it was an absolute requirement to have the ability to foresee how changes in one project would impact the others and then make the necessary design adjustments to stay on course. If, for example, the builders realized that the designers will need to make changes in the high level approach, the cable stay design could need to change as well.
For example, at a critical point in the program, the joint venture’s cable supplier was suddenly unable to ship any more cable because its steel supplier had gone bankrupt. The program literally ran out of cable as a result. The joint venture was able to line up a new supplier, but the process was extremely complicated because producing the cable required aligning a complex supply chain of specialized steel, cable pulling capacity, cable coating, and shipping.
"Just in the nick of time, we were able to work out a deal that would supply us with cable," Watson said. "But in the meantime, we had to completely reanalyze the schedule and create many different scenarios to keep the program on schedule. Without that ability, our task would have been much more difficult.
The joint venture used an integrated construction management solution (ICMS) to keep the program on schedule and effectively manage the disparate project elements. The ICMS provided everyone involved with the project with a home for the master schedule, a central repository of contracts and a data center to organize all project information, each of which was tied together. That solution was Primavera.
"Primavera helped us move forward on all aspects and adjust plans quickly when necessary," Watson said. "We were able to deliver the completed bridge one year ahead of schedule due in large part to our use of Primavera software."
But there was much more behind the joint venture’s success than its use of Primavera. The firms instituted a host of best practices around the ICMS to ensure on-time delivery of the first four lanes, and then the final delivery of the rest of the bridge just two months later, a year ahead of schedule. Some of the primary best practices the joint venture implemented included:
1) Create a rigorous, documented, system-driven change management process: The joint venture implemented a change management process that enabled the design and build teams for each of the five projects to work together effectively and efficiently. Each project depended on the timely completion of the others in order to meet objectives, so a change in one project could easily cause cascading delays through the entire program unless corrective action was taken immediately. The firm deployed a centralized system in which every stakeholder had relevant access to the files that pertained to their work. If a change occurred, all responsible parties were notified and the approved RFI was then routed back to the person who originated it. This workflow kept everyone informed and gave visibility to program managers into how much change was going on and how much these changes would cost.
2) Implement a robust technology platform for standardized communication and collaboration: Close collaboration was essential to the success of the Cooper River Bridge. For instance, the cables were strung before the towers were finished, a measure that saved a great deal of time. Only through continuous collaboration among the many stakeholders could such a feat be accomplished. The joint venture also developed communication protocols that established standards for how information would be relayed throughout the team. Leveraging technology enabled the firm to establish standard operating procedures which allowed for full accountability throughout the life of the project.
3) Develop project health indicators: With an ICMS deployed, the joint venture was able to design an easy-to-use system for evaluating the status of each project. And because these indicators were standardized, there was a single version of the truth across the entire program. Some of the lagging indicators included: schedule variance, cost variance, actual cost vs. baseline cost, schedule milestones accomplished, cash flow to date compared to budget, and productivity to date. Leading indicators included: projected total cost to complete, projected completion date, and projected cash flow. These indicators acted as early warning systems that flag potential problems before they become crises and enabled the joint venture to compare progress across all of the bridge projects — giving the program manager a more accurate big picture on the health of the overall program.
4) Run multiple forecasting scenarios: This capability was crucial for developing plans not only to deal with potential delays before they happened, but also to enable value engineering that would save time and money. Forecasting enables project management executives to model time and cost savings to determine the best and most effective project path forward. It enables "what-if" scenarios once a change has occurred to find the best path for mitigating delays and additional costs to the highest degree possible.
"This was a massive program," Watson said. "But because we implemented standards for communication and collaboration, followed best practices for program management and deployed a robust technology platform that could manage the program and help us foresee potential problems before they became crises, we were extremely successful and delivered the bridge early to the customer."
INFO: Primavera Systems (www.primavera.com)