UndergroundStructuralGeneralAdvances in Silicate Accelerators for Shotcrete
Vicky Sidorkiewicz and Michael McDonald
Read MoreSodium silicate has long history of use in construction and geotechnical applications due to its versatility and reliable performance. In shotcrete placement, sodium silicate solutions were widely used as…
UndergroundStructuralGeneralAutomated Shotcrete Application in Tunnelling
Igor Schweiggl, Rainer Antretter, Alex Sellemond, Norbert Fügenschuh, and Peter-Rolf Dietrich
Read MoreThe tunnelling industry has again been working toward the automation of shotcrete application for some years now, after research and development stalled around 2005. Robots had been developed with the capability of…
UndergroundStructuralGeneral2025 Carl E. Akeley Award: “Shotcrete as Final Liner – Design Considerations”
Andy Thompson
Read MoreThe 20th annual Carl E. Akeley Award was presented to Andy Thompson for his article, “Shotcrete as Final Liner — Design Considerations,” which was published in Shotcrete magazine, Volume 27, Number 3, 3rd Quarter 2025. The article discusses how shotcrete (often called sprayed concrete) is
UndergroundStructuralGeneralHumber College Station Shotcrete Construction: Design, Sustainability, and Execution – 2025 Outstanding Infrastructure Project
Ross King
Read MoreHumber College Station is located at the west end of the 6.4 mi (10.3 km) Finch West LRT, which includes 16 stops and two below-grade terminal stations. The Humber College Station is constructed below grade, however open to daylight, which presented unique logistical, structural, and
UndergroundGeneralNew York City Grand Central Station New Passageway – 2025 Outstanding Underground Project
Louis Falco
Read MoreThe prestigious Grand Central Station is located in a major hub center of New York City bound by East 42nd Street (south), Lexington Avenue (east), East 51st Street (north), and Madison Avenue (west). As one of the major hub centers…
UndergroundStructuralGeneralCommentariesWinter 2025 Follow up on Early Strength Testing
Christoph Goss, PhD, PE, PMP, F.ASCE
Read MoreIn my last column, I discussed the need for early strength testing in underground shotcrete…
UndergroundGeneralCommentariesHow Do You Recruit for an Invisible Job?
Maria Chastka
Read MoreYou can be working on a large-scale, technically challenging, resource-consuming project … and if it goes well, people will not even know you’re there. Herein lies one of the struggles the tunneling industry faces: If people aren’t aware the projects exist, they also don’t know there are jobs available…
RepairUndergroundGeneralTraffic Repairs Using Low-Dust Shotcrete Material: Monitor-Merrimac Tunnel Project
Thomas Brennan
Read MoreHistorically, the dust associated with dry-mix shotcreting caused hesitation in projects in urban or live traffic environments; however, recent innovations in low-dust materials have significantly changed planning considerations…
UndergroundStructuralGeneralShotcrete Placement for Initial Support: Climate Pledge Arena Tunnel Project
Mark Pinske, Elizabeth Lenker, and Paul Mockus
Read MoreThe Washington State Coliseum was an arena built for the 1962 Seattle World’s Fair. More than half a century later, in 2019, a $1B construction program began to redevelop and expand the arena. The redeveloped building, with a new name — Climate Pledge Arena — retains the historical roof, but
UndergroundStructuralGeneralShotcrete as Final Liner — Design Considerations
Andy Thompson
Read MoreThe use of shotcrete placement (often called sprayed concrete) for the final permanent structural lining of underground structures and facilities continues to increase around the world. Where non-uniform shapes are required, shotcreting provides…