Smart Engineering has participated in the design, optimization of the reinforcement and monitoring of the work of the CSST-Ottawa project in the city of Ottawa, Canada. The CSST-Ottawa project is a strategic initiative and one of the most important projects of the Ottawa River Action Plan (ORAP), which is the City of Ottawa’s long-term strategy to improve stormwater management and improve and protect Ottawa’s health. The CSST-Ottawa project includes the construction of two tunnels, an east-west tunnel through the city center from LeBreton Flats to New Edinburgh Park, and a north-south tunnel (NST) along Kent Street from Chamberlain Avenue to the existing storm sewer at the mouth of the Ottawa River north of Wellington Street.
The CSST-Ottawa project has as its main objective will greatly reduce the frequency of overflows when entering the Ottawa River; It will contain up to 43,000m3 of sewer overflow during the major rains, which can then be safely treated and returned to the Ottawa River. In addition to reducing overflows when entering the Ottawa River, the benefits of the CSST-Ottawa project include reducing the risk of basement flooding for various lowlands in the Glebe / O’Connor area, and increasing operational flexibility and redundancy to the main collection sewers in the downtown area.
The CSST-Ottawa project is carried out by applying the TBM machine construction technique for excavation and the use of precast concrete segments to support the tunnel. Smart Engineering has participated in the design and optimization of the structural reinforcement of the latter, together with the companies Intecsa and Dr. Sauer. The final solution adopted has been the use of steel fibre reinforced concrete. In this way, it has been possible to respond not only to the mechanical stresses that take place during the transitory stages of manufacturing (demoulding, transportation and stockpiling on site), as well as in service.
Likewise, Smart Engineering has collaborated during the construction work of the CSST-Ottawa tunnel together with the companies Dr. Sauer, Intecsa, Ggravity and Dragados Canada. Smart Engineering has supported the optimization and monitoring of the curing of the manufactured voussoirs, as well as the evaluation and validation of the mechanical performance of the manufactured voussoirs. The follow-up was quite a challenge, since different tests were carried out to validate the curing conditions in extreme conditions due to the temperatures reached in winter in the city of Ottawa. Laboratory scale studies were carried out to determine the influence of curing conditions on the mechanical properties of the material, as well as real scale studies. Smart Engineering collaborated with the University of Ottawa to carry out full-scale trials of segments made in the project, testing a total of 6 segments. To complement the study, Smart Engineering developed specific numerical models to validate the expected mechanical behavior of the segments made, considering the curing conditions.