McCarran International Airport
MSE Wall/Helix Bridge/Taxiway Bridge Repair

Sigma Engineering Solutions, Inc. is presently under contract with the Clark County Department of Aviation to provide an existing mechanically stabilized earth (MSE) wall repair and drainage improvements, as well as repairs to three bridge superstructures located at the McCarran International Airport, located in North Las Vegas, Nevada.

An existing MSE wall located near the main Terminal has moved due to a buildup of hydrostatic pressure behind the wall. The solution consists of the installation of a storm drain system behind the wall, which will collect and divert the water from behind the wall. The unpaved area behind the existing MSE wall will be covered with asphaltic concrete pavement to prevent further water from seeping and creating hydraulic pressure.

As a part of researching the cause of the water build-up behind the MSE wall, Sigma also discovered that three nearby bridge superstructures were suffering from serviceability issues associated with the original system’s design. Plastic drainage piping originally installed with the bridges had cracked and come apart inside the bridge decks, causing water to build up over time and seep through the concrete decking showing up as efflorescence on the soffit of the bridge deck. Other problems included conditional degradation of prior repairs of deck joints, unrepaired concrete spalling which had exposed reinforcing steel and surface cracking on the deck of the bridges.

Sigma’s Tasks for the repair of the Helix Bridge and Taxi Bridge Superstructures includes the replacement of the deteriorated interior drain pipe system, cleaning mineral deposits from the deck soffits, repairing corroded bridge deck access hatches, coring and installing new bridge deck cell vents and removing and replacing existing deteriorated compression joint seals. This project also includes the installation of a new joint seal assembly at the intersection of the Pedestrian Bridge and Taxi Bridge, as well as methacrylate concrete deck crack sealing and minor concrete spall repairs.