Delhi Metro Phase-IV Design: Track Geometry & Rolling Stock Specifications (Part-1)

Delhi Metro Phase-IV Design Specifications: Track, Structure & Rolling Stock

Introduction to Delhi Metro Phase-IV Design Specifications

design specifications for the Phase-IV expansion. “>The Delhi Metro Rail Corporation Ltd. (DMRC) outlines comprehensive design specifications for the Phase-IV expansion. This document details critical aspects such as track geometry, track structure, and rolling stock requirements.

Track Geometry and Structure Specifications

Track Geometry: As per the approved Schedule of Dimensions (SoD) by DMRC. Key parameters include:

• Gauge: Standard Gauge at 1435 mm.
• Track C/C Distance: As specified in SoD.
• Rolling Stock Width: 3200 mm.
• Maximum Gradient: As per SoD.
• Track Type: Ballastless design.

Roadway and Railway Clearances

Clearances for Road Traffic: Must comply with Clause 104.4.2 of IRC: 5, ensuring a minimum of 5.50 m clearance from the crash barrier to the pier shaft. The clearance from road level to the soffit of the Metro structure must be maintained at 5.5 m.

Clearances for Railway Traffic: Follow the Schedule of Dimensions (SoD) of Indian Railways and DMRC. Railway crossing arrangements require approval from the relevant Railway Authority.

Clearances for Rolling Stock: Adhere to the approved Schedule of Dimensions by DMRC for rolling stock.

Design Life & Serviceability

The main structural systems should have a design life of 100 years, as per Clause 15.1.3 & 16.1.3 of IRS-CBC and Clause 3.6.5 of the IRS Steel Bridge Code.

Materials Parameters

Concrete Specifications:

• Young’s Modulus: Follow Clause 5.2.2.1 of IRS-CBC.
• Modular Ratio: As per Clause 5.2.6 of IRS-CBC, m1 = 280/fck for tensile reinforcement and m2 = 420/fck for compression reinforcement.
• Cover Requirements: Minimum cover for foundations is 75 mm, as per Clause 5.4.4 of IRS-CBC.
• Cement Specifications: Follow Clause 4.1 and other relevant sections of IRS-CBC.
• Density: Concrete density is 25 kN/m³ for PSC and RCC, 25 kN/m³ for plain cement concrete, and 26 kN/m³ for wet concrete.
• Poisson’s Ratio: Set at 0.15 for all concrete grades.
• Thermal Expansion Coefficient: Coefficient of 11.7 x10⁻⁶ °C⁻¹, in accordance with Clause 2.6.2 of IRS-Bridge Rules.

Prestressing Steel for Tendons:

• Characteristic Strength: Follow Clause 4.6 of IRS-CBC.
• Prestressing Units: Type 0.6” strands (Nominal diameter = 15.2 mm, Area = 140 mm²).
• Breaking Strength: 260.7 kN.
• Breaking Stress: Minimum of 1860 MPa.
• Young’s Modulus: 195.0 GPa as per § 4.6.2.1 of IRS-CBC.
• Sheathing: Corrugated HDPE ducts with specific diameter and wobble requirements.

Reinforcement Steel (REBARS):

• Grade: Fe-500D, conforming to IS 1786 and IRS-CBC.
• Young’s Modulus: 200,000 MPa.
• Yield Stress: 500 MPa.
• Density: 78.5 kN/m³.

Conclusion

These specifications are essential for ensuring the safety, durability, and efficiency of Delhi Metro Phase-IV. Adhering to these detailed guidelines will support the successful implementation of this significant infrastructure project.

Saraswati Chandra Project Manager

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