A Towering Challenge

It’s no secret to the daily drivers in the Sacramento region that our local roads, freeways and even bridges have some less-than-perfect driving conditions. Any observant motorist can attest to this fact with their own experiences of avoiding potholes, deciphering sometimes illegible road markings, and bracing for strong bumps when crossing gaps between roadway segments.

What may surprise you, however, is the staggering amount of data freely available to the public which, when drawn together, paints a dire portrait for the future of Sacramento roads. In a nutshell: There are many existing problems we know about, not enough money to properly contain these problems in a timely fashion, and not nearly enough funding dedicated for proactive maintenance projects or to build the new infrastructure needed to replace functionally obsolete roads and bridges.

LEARNING FROM HISTORY

There is a fable which says if a frog is placed in boiling water, it will jump out, but if it is placed in cold water that is slowly heated, it will not perceive the danger and will be cooked to death. The same metaphor could ring true for the public’s inability to react to significant changes that occur slowly over time.(1) It could even be said that the I-35W Mississippi River bridge collapse of 2007 is a terrific example of this idiom.

The warning signs were visible to those in charge of bridge maintenance and safety in Minnesota. In 1990 the federal government gave the I-35W bridge a rating of “structurally deficient,” mainly because of the significant amount of corrosion in its bearings. In 2001 the University of Minnesota’s civil engineering department released a study highlighting the cracking in cross girders near the ends of the approach spans. Finally, in 2005 the U.S. Department of Transportation’s National Bridge Inventory database found signs of fatigue and brought up the possibility of the need to replace the bridge entirely.

Despite all of these warnings, on Aug. 1, 2007, the I-35W bridge fell into the Mississippi River during the evening rush hour, killing 13 people and injuring 145. Officials were either unaware of or grossly unable to fully understand the fragility of the bridge. Despite its impending doom, at the time of the collapse there were over half a million pounds of construction supplies and equipment on the bridge for crews to replace lighting, concrete and guard rails.(2)

OBSERVING WITH OUR EYES

While the roads and bridges in the Sacramento region do not copy the “Truss Arch” design that proved faulty in Minnesota, they do share other commonalities. These include their age, heavy truck use and the same federal rating of being “structurally deficient” in many cases. Perhaps one of the most glaring examples of road fatigue that observers were able to witness with their own eyes until recently was the off-ramp for the Eastbound “W X” Highway 50 to Highway 99 South.

For several years, large makeshift steel braces held up one section of roadway that was separating from the other. Drivers above the bracing could feel a large jolt as they drove over the crumbling “hinge.” This shift in the bridge span also produced a visible change in road elevation between sections. Last summer a construction bid was awarded to a private firm and work began to build a new concrete pylon to provide support to the off-ramp. Finally, near the end of 2010, work was completed and the temporary bracing was removed.(3)

The bump on the roadway still remains and, according to CalTrans, will be smoothed out sometime in the spring when warm weather conditions are more conductive to concrete work. But what of the dozen or so other local bridges that appear to share the same visible road-elevation changes between sections of roadway?

WARNING SIGNS?

Most of the major elevated freeways built in the Downtown Sacramento area were built in the 1960s.(4) They are a mix of bridges and ramps that span over earth, rivers and, in some cases, over other roads. Most have flexible divisions which are designed to allow the road to give and take depending on mitigating factors such as heat, cold and rising tides. These divisions sometimes connect elevated sections back to sections of road that are on improvised mounds of earth. It is at these sections that the careful observer can see astonishing changes in roadway elevation.