(Doha, State of Qatar)
We conduct research for various customers on resistance to dynamic loads on mechanical splices for the high-speed rail line being constructed between Mumbai and Ahmedabad.
The Mumbai-Ahmedabad high-speed rail will begin from Mumbai’s Bandra Kurla Complex and end near Sabarmati railway station in Gujarat, covering 12 stations in total. The stations covered by the project include Mumbai, Thane, Virar, Boisar, Vapi, Bilimora, Surat, Bharuch, Vadodara, Anand/Nadia, Ahmedabad and Sabarmati.
As is the case with many stations, bridges and tunnels, couplers are also used in this project to connect reinforcing bars. Because of the dynamic load that occurs when a high-speed train travels along the route, laboratory testing must be used to demonstrate that the mechanical splices can withstand these forces. The NHSRCL has drawn up a technical document in which the requirements for this dynamic load are described. For each bar diameter that is used, tests must be performed with different dynamic tensile loads and a minimum tensile load of 30 MPa. The dynamic loads to be tested must be determined by the manufacturer and are between 100 and 350 MPa.
Based on the test results, a so-called S-N curve is drawn up in which the Stress amplitude is plotted against the Number of cycles, until the mechanical splices break (see example below).
Based on formula (f-1) in document MAHSR-C-4 – Part 2, a line is drawn in the graph that serves as the lower limit. More than eight mechanical splices per diameter should be tested and the test results must be above the f-1 line.
Concrefy takes care of the tests, we advise on the dynamic loads to be applied and we provide the report including S-N curve.
Please feel free to contact our specialist Peter Megens with any questions about this research.