The art of rehabilitation of tunnels has flourished and developed significantly over the last couple of decades. Several hundred railroad, highway, and conveyance tunnels have been successfully rehabilitated, converted, and/or enlarged. Much of this development can be attributed to the successful use of steel fiber-reinforced shotcrete. The flexibility and adaptable nature of steel-fiber microsilica shotcrete is ideal for rehabilitation of tunnels. Thanks to shotcrete, enlargement and rehabilitation of tunnels without fully taking the tunnel out of service is not only technically but also economically feasible consid-ering the cost of other alternatives including the œdo nothing alternative. Enlargement was usually accomplished by raising the crown but some have been enlarged by lowering the invert, which is much more difficult and time-consuming.
Tieton Dam Spillway Rehabilitation
Johnson Western Gunite Company rose to the challenge of rehabilitating the Tieton Dam Spillway in Yakima, WA. The spillway, built originally in 1924, was showing significant deter-ioration due to freezing and thawing, weathering, and erosion due to high-velocity water flow. The owner, the United States Department of the Interior Bureau of Reclamation, designed a repair consisting of a 12-in.-thick (300 mm) reinforced, cast-in-place concrete overlay on the floor and left wall if one was looking downstream. The budget in the original contract was not sufficient to overlay the right wall.
Shotcrete Repair in Paper Mill
March 2002, and May 2002. Work was conducted inside process vessels in a pulp mill by the specialized lining contractor, Canadians Stebbins Engineering Ltd., and the shotcrete contractor, Béton Projeté M.A.H. Due to operational constraints and significant costs involved with downtime, the contractors™ primary goal was to perform a repair that would provide long-term reliability within the shortest construction period possible.
Grain Silo Rupture Repair
Barlett & Co. faced a huge cleanup job at its 6.9 million-bushel trail terminal in Wichita, Kanasas in the fall of 1999. A grain silo in diameter and tall holding roughly 150,000 bushels.
Designing and Installing a Shotcrete Strengthening Application on the Spokane Street Bridge
The Spokane Steet Bridge connects the community of West Seattle to downtown via Highway 99 and Interstate south of the city center. The bridge was not originally and constructed to handle is present-day usage consequently.
Use of Synthetic Fiber-Reinforced Dry-Mix Shotcrete for the Rehabilitation of a Wharf in Northeast Quebec, Canada
Use of Dry-Mix Shotcrete to Repair a Lighthouse Structure
This paper presents a description of the repair work carried out in 1996 at the Haut-Fond Prince lighthouse structure located in the St. Lawrence River, 8 km (5 mi) from the coast of Tadoussac, Quebec, Canada. The damaged section of the structure in the tidal zone was repaired using dry-mix shotcrete. Due to the particular field conditions (freezing-and-thawing cycles, ice erosion and im-pact, submersion of the repair zones only minutes after the application of shotcrete, etc.), the mixture used contained high early strength cement, silica fume, steel fibers, a liquid air-entraining admixture, and a powdered set-accelerator admixture. Removal of deteriorated concrete, preparation of the surface, replacement of the reinforcement, specifications for the shotcrete produced, as well as the application procedures are described in this article. A certifica-tion session was held to verify the skills of the nozzlemen. Only those qualified were authorized to apply shotcrete on the structure.
This article describes the repair work carried out at the Haut-Fond Prince structure located in the St. Lawrence River at the confluence of the Saguenay and the St. Lawrence rivers, 8 km (5 mi) from the coast of Tadoussac, Quebec, Canada (Fig. 1).
New Mixture Design and Guide Specifications and Inspector’s Manual
Shotcrete has not traditionally been a material of choice for repair of bridge structures by many state highway departments. One reason for this is that bridge engineers have not been aware of advances in the quality and durability possible with high-performance shotcrete over the last 10 to 15 years. In 1995, an effort was made to help facilitate and encourage the use of shotcrete in bridge repair, especially where it is particularly advantageous: in overhead and vertical surfaces and in thin layers, or a combination of thin and highly reinforced thick layers. The effort was organized by the AASHTO-AGC-ARTBA Joint Committee.
Shotcrete with Steel Fiber Helps Reinforce Mount St. Helens Project Savings
Thirteen-hundred feet (400 m) of the peak collapsed or blew outwards. As a result, 24 square miles of the valley was filled by a debris avalanche of recreation.
Evolution of Fiber Reinforced Shotcrete
The concept of reinforcing shotcrete with discrete, disominous steel fibers was developed by the Battelle Research Corporation in the USA in the early 1970s.