Industry Should Welcome CDOT's Standard Special Provision Announcement

By Taka Kimura, PE
Lead Structural Engineer
Parsons Brinckerhoff
Member ACEC/CO
Structures Committee Chairperson, ASCE

The C-470 girder collapse on May 15 affected me in much the same way it affected many other engineers. A collapsed structure is something we all dread and the sight of that toppled girder sent chills down my spine.

After the initial shock subsided, a nagging question remained: "Could this happen on any of my projects currently being constructed?"

Engineers in general are fairly cautious people. We have to be. Yet, despite all the calculations, checks and safety factors, bridges are designed and built by humans and, as a result, there is always the chance for error. As a design professional, it is my responsibility to minimize that uncertainty, and that is why I was pleased by the new Standard Special Provision released by CDOT on August 9.

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Important Revisions

The new Standard Special Provision, which takes effect immediately, revises sections 509 and 618 of the CDOT Standard Specifications for Road and Bridge Construction. The additions to the Specifications, which deal with steel and concrete girder erection, can be summarized as follows:

• Girders shall be anchored and braced during erection.
• All temporary restraints shall resist all loads until completion of the deck.
• At least four weeks before girder placement, the contractor shall prepare and submit a girder erection plan.
• A pre-erection conference will be held at least two weeks before girder erection.
• Each girder installation phase shall be inspected and approved in writing by the contractor's engineer before allowing vehicles or pedestrians on or below the structure.
• The contractor shall inspect the erected girders daily until completion of the deck.

Checks and Balances

These modifications to the CDOT specifications are an effort to reduce the uncertainties faced by everyone in the construction industry. This new system of checks and balances outlines actions to be taken before, during and after a girder is erected. The planning phase has been formalized to minimize any predictable problems and streamline the erection process.

Unfortunately, things occasionally slip through the cracks of any planning process. As a result, CDOT has instituted several mandatory inspections, by both contractor and engineer, during and after girder placement to ensure that everything is done as accurately as possible. These clarifications of the roles and responsibilities will reduce the chance that any tasks are overlooked.

One could speculate about whether these changes could have prevented the May 15th girder collapse, but with so many factors likely contributing to the tragedy, there is no way to tell conclusively. What is clear is that rather than waiting for the NTSB investigation results, CDOT has proactively taken steps to reduce the chances of a similar accident from happening again.

Not only will these new changes help protect the public, they also protect the construction industry. High-profile accidents erode the public's confidence in our ability to safely do our work, no matter who's at fault. Any step taken to minimize construction accidents benefits the construction industry as a whole.

While there is no perfect system that prevents all construction accidents, the new CDOT Standard Special Provision helps reduce the chance of them happening and gives some remedy to the chill that I felt down my spine that Saturday morning in May.

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