MUMBAI, India, June 22 -- Intellectual Property India has published a patent application (202641068809 A) filed by D Jeetendra Prakash; and P Sravana on June 01, 2026, for Rail Structure Interaction Analysis For Providing Continuous Welded Rail On Unballasted Steel Through Girder Bridge Carrying Dedicated Freight Corridors Loading.
Inventors include D Jeetendra Prakash; and P Sravana.
The application for the patent was published on June 12, 2026, under issue no. 24/2026.
Abstract: Rail-Structure Interaction (RSI) requires thorough study to understand the force transfer mechanism between the track and bridge components due to train vertical live loads, braking/traction loads and thermal loads. RSI analysis provides an outline of axial stress in rail, support reactions transferred to the bridge components and the relative displacement caused between the track and bridge all of which are critical to ensure the structural integrity and operational safety of railway bridges carrying heavier axle loads. This research presents a comprehensive investigation of RSI phenomena for implementing Long Welded Rail (LWR)/ Continuous Welded Rail (CWR) on un-ballasted steel through girder railway bridges carrying Dedicated Freight Corridor (DFC) loading of 32.5t axle load. The study evaluates three bridge configurations to determine the feasibility of Continuous Welded Rail (CWR) provision, including two multi-span open web steel girder bridges—Bridge-1 with a span arrangement of (7 × 63.7 m) and Bridge-2 with (6 × 48 m) analyzed using the graphical guidelines of UIC 774-3R and a simply supported single-span bridge, Bridge-3 (1 × 78.8 m), which was assessed through MIDAS beam element modeling along with theoretical calculations based on UIC 774-3R. For the multi-span bridges, the combined axial stresses at the movable supports were found to be significantly high, reaching (-)139.56 N/mm² for Bridge-1 and (-)124.78 N/mm² for Bridge-2 respectively under CWR conditions, which far exceed the permissible limits. In contrast, the axial stresses at the fixed supports were 43.53 N/mm² and 52.48 N/mm² respectively, remaining within the allowable limit of 72 N/mm². In the case of the single-span bridge (1 × 78.8 m), braking loads of 16.3 kN/m resulted in moderate axial stresses ranging from 20.3 to (-)26.6 N/mm² at fixed and movable supports respectively. However, a temperature variation of 35°C produced substantially higher axial stress at the movable support ((-)76.3 N/mm²), compared to a minimal value at the fixed support (2.7 N/mm²). Vertical bending effects were found to be the most critical, generating compressive axial stress of (–)80.4 N/mm² at the movable support, which exceeds the allowable limit of 72 N/mm². Although horizontal displacements with CWR remained within the allowable limit of 5 mm for most cases, the pier displacement in Bridge-1 reached 6.145 mm, exceeding the permissible value. Overall, the combined analysis of stresses and displacements across all bridge configurations clearly indicates that direct provision of CWR is not feasible for these bridges. Instead, the installation of Switch Expansion Joints (SEJ) at each support location is necessary. The provision of SEJs ensures compliance with UIC 774- 3R requirements, with all horizontal displacements remaining well within the allowable limit of 30 mm.
Disclaimer: Curated by HT Syndication.
