UndergroundGeneralPerformance of Synthetic Sheet Waterproofing Membranes Sprayed with Steel Fiber-Reinforced Shotcrete
Antoine Gagnon, Marc Jolin, and Jean-Daniel Lemay
Read MoreThe recent Position Statement #2, “Spraying Shotcrete on Synthetic Sheet Waterproofing Membranes,” published by the ASA Underground Committee, pointed out many aspects critical to successful performance and raised some potential issues affecting the placement.1 In the position statement, specific techniques are presented to prevent problems
UndergroundGeneralFiber-Reinforced Shotcrete Applications and Testing Overview
Antoine Gagnon and William (Bill) Geers
Read MoreThe addition of fibers to concrete and mortars as reinforcement is not a new concept. The ancient Egyptians used straw to reinforce mud bricks for use in structures like the core walls of the pyramids. During the first century AD, the Romans incorporated horsehair fibers
UndergroundMaryland Purple Line Plymouth Tunnel
Nick Tabor and Norbert Fuegenschuh
Read MoreThe Plymouth Tunnel is a 1020 ft (311 m) sequential excavation method (SEM) tunnel located in Silver Spring, MD, that makes up a portion of the Maryland Transit Authority’s (MTA) Purple Line light rail connecting the existing metro lines around Washington, DC. The Purple Line
RepairUndergroundTiber Creek Sewer Rehabilitation
John Becker and Randle Emmrich
Read MoreAs part of the DC Clean Rivers Project ? Division 1 Main Pumping Station Diversions, the Tiber Creek trunk sewer was designated to receive a new structural liner in a 122 ft (37 m) section near the intersection of New Jersey Ave. and Tingey St.
RepairUndergroundQueens Midtown Tunnel Rehabilitation
Ashley Cruz
Read MoreThe Queens Midtown Tunnel (QMT) is a twin-tube, tolled, four-lane highway that serves over 90,000 vehicles each day.
UndergroundTunnel Shotcrete Lining for Hydroelectric Projects
Lihe (John) Zhang, Dudley R. (Rusty) Morgan, Serge Moalli, David Gagnon, and Danny Dugas
Read MoreIn British Columbia (BC), Canada, the primary source of power supply is hydroelectricity.
UndergroundStructuralStructural Modifications to Hydroelectric Turbine Draft Tube Ceiling
Shaun M. Radomski, Dudley R. (Rusty) Morgan, Lihe (John) Zhang, and David Graham
Read MoreThe U.S. Army Corps of Engineers (USACE) is engaged in structural modifications to the reinforced concrete draft tube exits from the turbines in the Ice Harbor Lock and Dam located on the Snake River near Burbank, WA.
UndergroundFlood Control Channels Made with Shotcrete
Raúl Bracamontes
Read MoreFlooding is a temporary overflow of water onto land that is normally dry. Floods are the most common natural disaster in the United States.
UndergroundOverhead Shooting against PVC Membrane
Frank E. Townsend III and Dennis Rubi
Read MoreOverhead shotcrete application against any substrate is challenging. Shooting against a polyvinyl chloride (PVC) membrane waterproofing system increases the difficulty and danger of the process.
RepairUndergroundShotcreting the East Side Access Program
Frank E. Townsend III
Read MorePrior to 9/11, all structural wall and tunnel concrete applications in New York, NY, used the form-and-pour concrete placement method.