The Michigan Department of Transportation (MDOT) plans to allocate approximately $80 million on a 1.2-mile section of Route US131 in downtown Grand Rapids, according to MDOT Region Engineer Steve Earl. The section, called the "S-Curve," is a winding series of surface and elevated highway and six bridges.

Discovery of some structural settlement and the need to fix it presented an opportunity to also straighten and widen the roadways, from three to four lanes in places - much needed renovations for a section that carries 100,000 vehicles per day.

Prior to construction it was necessary to locate any buried utilities. Project managers have learned the hard way that a lack of accurate utility mapping can cause costly conflicts, damage, delays, service distributions, redesigns, claims, and even injuries and deaths. Consequently, the authorities requested Subsurface Utility Engineering (SUE) before letting any renovation.

MDOT brought in TBE Group Inc., of INdianapolis, Indiana, which used a variety of invasive and noninvasive tools, including electromagnetic detection, ground-penetrating radar, and acoustical and pulse induction.

Despite the sophistication of the tools, though, a thorough SUE team is skeptical of depth readings, and will usually locate anything critical physically. Such was the case here, when a 24-inch gas transmission main was suspected to be in conflict with probable construction. According to TBE Assistant Project Manager Jeff A. Sowers, P.E., they used an air lance at 165 psi to dig nondestructively and locate the main. It turned out to be at between 0.5 and 1.7 meters deep in different spots, and will be relocated by open trenching.

Design is approximately 70 percent complete by lead design firm Consoer Townsend Envirodyne and its affiliates. The goes out for bids this December.

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Publication(s)
Engineering News Record
August 30, 1999