I-29/U.S. 275/IA 92 interchange, USA

ROAD IMPROVEMENT AT COUNCIL BLUFFS, IOWA

The I 29 - US 275 - IA 92 interchange project is part of a broad road improvement programme initiated by Greater Council Bluffs, Iowa.

The project’s constraints included the impossibility of using prefabricated drains within 150 metres of a flood control embankment. To overcome the problem, Menard primarily used the Controlled Modulus Column technique to reinforce the soil supporting the interchange, with drains in areas where they could be used. Menard installed 14,000 columns with a diameter of 45 cm and a total of 54,800 linear metres of drains in soil composed of 6 to 12 metres of soft clay over dense sand. Working to a very tight schedule, Menard completed the improvement project covering seven different types of soil with the required timeframe, making it possible to accelerate backfilling operations.

In March 2015, Menard won a further works package on the same project.