Since shotcrete is pneumatically placed against a one-sided form there is no liquid concrete pressure against the form. When bench shooting vertical walls the majority of pressure from the high velocity impact is carried by the previously placed concrete as the concrete is stacked. Plus, this pressure is very localized, only affecting a small zone immediately adjacent to the impact area of the material stream. Here is an article on a research project that quantified the force https://shotcrete.org/wp-content/uploads/2020/05/2007Sum_TechnicalTip.pdf
From the paper conclusion “In normal spraying conditions, wet- and dry-mix shotcretes produced a force on the panel of about 45 and 20 lb (200 and 90 N), respectively. The maximum load recorded is 87 lb (389 N) and it was observed in simulating a water plug.”
If your shotcrete form is exposed to wind forces before placing shotcrete, you may want to consider the wind pressure that may be expected across the entire form during construction to keep the form intact. This should be much less than the 50 lb/ft2 pressure you mention. ACI formwork design is intended for cast concrete where liquid concrete is contained within a two-sided form and is NOT applicable to shotcrete placement. Some sources show a 60 mi/hr (100 km/ hr) wind exerting about 10 lb/ft2 (50 kg/m2) on a vertical wall.
Shotcrete is a placement method for concrete. Thus, generating the maturity curves would be based on the concrete mixtures. There are several online resources about the maturity method. One that discusses production of the curves is from the Minnesota DOT and available in PDF format at www.dot.state.mn.us/materials/concretedocs/MaturityMethodProcedure.pdf.
BRIDGE HISTORY Listed on the National Register of Historic Places in 1989, the 10th Avenue Bridge in Minneapolis features seven reinforced
concrete arches to span the Mississippi River. The historic 1,141-ft (348 m) open spandrel column arch structure carries over 10,000 vehicles daily, as well as hundreds of pedestrians and cyclists between downtown Minneapolis and an area dominated by the University of Minnesota on the east bank.
We got a call from one of the local drilling contractors, Braestone Rockworks to check out a shotcrete shoring project down at Deep Cove
in North Vancouver, British Columbia.
In the summer of 2018 Morningstar Homes retained GeoPacific Consultants for the geotechnical design of a proposed development of 109 single family residential lots.
UMA Geotechnical Construction Inc. (UMA) typically finishes off the soil nail walls it constructs with a
standard shotcrete finish. But sometimes the owner wants a more artistic approach.
That was the case for North Carolina Department of Transportation (NCDOT) on the I-40/I-77 interchange
improvements project in Iredell County. UMA was contracted by Lane Construction to install roughly 45,000
ft2 (4200 m2) of various sized soil nail walls with aesthetically appealing sculpted shotcrete finishes. UMA’s earth retention
work was first required to hold up cuts for widened roadway sections and to facilitate new bridge construction.
UMA is working as a geotechnical subcontractor to a Fluor-led joint venture (JV) with United Infrastructure Group, UMA to Break NCDOT Record for Largest Square Footage of Soil Nail Wall By Brian DeSpain, President, UMA Geotechnical Construction Inc. The project, formally known as NCDOT I-26 Exit 40 to I-40 Interstate Expansion Project, will help to alleviate traffic congestion and improve the safety and operational efficiency of this vital stretch of interstate in the Asheville area.
Wet-mix shotcrete has been used more and more for structural applications in the past few decades. Recently, wetmix shotcrete was successfully used to construct a mass structural wall with congested reinforcement and minimum dimensions of 1. 0 m in a sewage treatment plant.
Project Name:
Eglinton Crosstown LRT Project at Mt Pleasant Station
Location:
Toronto, Canada
Shotcrete Contractor:
Torrent
Architect/Engineer:
SNC-Lavalin
Material Supplier/Manufacturer:
Innocon Ready Mix & Canada Building Materials
Equipment Manufacturer:
REED Concrete Pumps
General Contractor:
Crosslinx Transit Solutions
Project Owner:
Metrolinx & Infrastructures Ontario
Shotcrete Consultant/Quality Inspections:
WSP E&I Canada Ltd.
I n early September of 2019, Gulf Coast Underground (GCU) received a call from the City of Baton Rouge and their construction manager, Jacobs Engineering Group (JEG). There was an issue at the South Wastewater Treatment Plant that would require a unique contractor skillset to properly repair. The problem was that the cast-in-place influent structures receiving 65 million gallons (246 ML) of sewer flow daily, were corroding and needed to be repaired quickly
