Advance Concepts of Launching Girder in Metro Railway

Abstract

The rapid expansion of metro rail networks in urban areas demands innovative construction techniques to ensure speed, safety, and minimal disruption to existing infrastructure. This paper explores advanced concepts in the implementation of launching girders, focusing on their evolving role in accelerating elevated metro construction. It highlights the engineering innovations, automation strategies, and real-time monitoring technologies that are redefining girder launching methods. The study also presents a comparativeanalysis oftraditionalversus advanced launching techniques, emphasizing improvements in structural integrity, operational efficiency, and worker safety. Case studies from recent metro projects provide practical insights into deployment challenges and the effectiveness of modern solutions. This paper aims to serve as a reference forengineers and project managers seekingtooptimizemetrorail construction through cutting-edge girder launching technologies. Case studies from recent metro rail projects in India and abroad are analysed to demonstrate the successful implementation of these advanced concepts, with metrics including reduced construction time, enhanced safety, andcost efficiency. The challenges associated with deploying advanced launching girders such as site constraints, logistical complexity, and workforce training are also discussed along with potential mitigation strategies.

Introduction

As cities grow more urbanized, the need for efficient, eco-friendly mass transit systems has increased. Elevated metro railways have become a popular solution due to their minimal ground-level disruption and faster construction compared to underground systems. A critical element in constructing these elevated corridors is the launching girder system, which places precast segments or girders that form the viaduct.

Traditionally, launching girders were operated manually or semi-mechanically, leading to limitations in speed, safety, and precision. Recent technological advancements have led to automated, hydraulic, and sensor-equipped launching girders, enabling faster, safer, and more accurate construction—even in complex urban layouts.

The paper focuses on using structural monitoring data (like strain responses) from the launching girder to track construction progress and productivity in real time. This approach involves analyzing strain patterns during key construction stages:

• Auto-launching: Moving the girder to the next span.

• Segment lifting: Raising and positioning precast segments.

• Post-tensioning: Stressing the joined segments to form a single unit.

• Span lowering: Transferring the span's load onto piers.

Each stage has a unique bending moment diagram (BMD), which reflects structural stress patterns. These patterns, captured by sensors like strain gauges and load cells, help identify the current operation and detect anomalies such as support settling or load variation.

The study also reviews literature showing the evolution from manual to advanced launching girders, highlighting the role of FEA, BIM, and sensor networks. Case studies from metro projects in India support these findings.

Methodology & Objectives

The paper proposes a new Automatic Data Collection (ADC) technique using structural health monitoring to:

1. Develop a wireless sensor network.

2. Identify optimal sensor placements.

3. Improve methods for determining the launching girder's condition from real-time sensor data.

Conclusion

Theimplementationofadvancedlaunchinggirdertechnologies hasmarked a significant leap in the construction methodology ofmetrorailwayprojects.Throughtheintegrationofhydraulic systems,modular structuraldesigns,real-timemonitoring,and digital tools such as Building Information Modeling (BIM), metroinfrastructuredevelopmenthasbecomefaster,safer,and more precise. While initial investments in advanced systems are relatively high, the long-term gains in efficiency, reduced project duration, minimized rework, and enhanced safety justify the costs.Moreover,thereducedimpactonurbantrafficandlower environmental footprint make these technologies more sustainable and suitable for modern cityscapes. In conclusion, the adoption of advanced launching girder concepts is not just an enhancement but a necessity for future metro rail projects, especially in densely populated and geometricallychallengingenvironments.Thesesystemsprovide a balanced solution that aligns with modern construction demands, safety standards, and sustainable development goals.

References

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Copyright

Copyright © 2025 Hitesh Shahare , Prof. Kshitij Thate, Er. Ketan Mase. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.