The Sahar Road Crossover Cavern (SRCC) is a tunnel with 6 symmetrical cross sections on Mumbai’s Metro Line 3. The SRCC’s original design called for a conventionally reinforced, cast-in-situ secondary lining. However, due to its complexity, Mumbai Metro Rail Corporation explored the use of sprayed waterproofing membranes (PSCL) and a drained regulating layer. These methods are a first for any Indian metro project. The drained regulating layer even is an international first. Success on the SRCC is expected to revolutionize India’s tunneling industry.
The Mumbai Metro tunnels are designed to last 120 years, so developing a high-quality, durable concrete mix was a key challenge, especially because the locally available sand and aggregates in Mumbai used in the concrete are variable and of poor quality. Also, the original design included rebars, but due to the cavern’s different cross sections and complexity, it was difficult to place them
For the permanent sprayed concrete lining the contractor used C32/40 concrete reinforced with 38 kg /m3 Dramix® 4D 65/35 BG steel fibers. Choosing a steel fiber reinforced design eliminated the need for traditional reinforcement. This way, the contractor significantly reduced complexity and material cost. It was the first time for the company to use steel fiber reinforcement for this application, rather than a traditional concrete reinforcement method.
As a result, the floors of the Linder facility reinforced with Dramix® 3D are highly resistant to impact and abrasion. By eliminating rebar, accelerating the speed of construction, and using less concrete, project costs were reduced by around 30%. Moreover, by reducing the amount of concrete used, the project met Linder’s sustainability objectives with the project.
As a result, the floors of the Linder facility reinforced with Dramix® 3D are highly resistant to impact and abrasion. By eliminating rebar, accelerating the speed of construction, and using less concrete, project costs were reduced by around 30%. Moreover, by reducing the amount of concrete used, the project met Linder’s sustainability objectives with the project.
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