This two-part session provides a comprehensive overview of precast concrete segmental tunnel lining systems, from design through production and construction. Presenters from industry, academia, and practice will explore critical topics including structural design, concrete technologies, fiber reinforcement, accessories, gaskets, formwork, precast production, contractor quality control, and durability-based design. Case studies and innovations from major international projects will highlight current challenges and emerging solutions. The session is designed to benefit designers, engineers, contractors, producers, owners, and young professionals engaged in underground infrastructure.
Learning Objectives:
(1) Demonstrate how advanced formwork systems and automated production technologies enable dimensional accuracy, reduce manual labor, and ensure consistent quality in precast tunnel segments;
(2) Explain the production process of precast tunnel segments, including critical inputs, outputs, sub-supplier roles, and decision points that impact quality, cost, and risk;
(3) Identify how quality control measures during precast segment manufacturing influence structural integrity, long-term performance, and project outcomes, using real-world contractor case studies to illustrate the impact of overlooked production details;
(4) Assess degradation mechanisms affecting precast tunnel linings and compare prescriptive versus performance-based service life modeling to inform material selection, detailing, and long-term reliability under diverse exposure conditions.
Formwork Systems and Automation for Tunnel Segment Production
Presented By: Stefan Medel
Affiliation: Herrenknecht Formwork Technology Gmbh
Description: Segment formwork used in tunnel construction differs from conventional concrete formwork, as it must achieve dimensional tolerances within millimeters to ensure accurate fit, prevent cracking during installation, and maintain gasket performance for watertightness. Herrenknecht AG – Division Formwork has pioneered the automation of segment production to meet growing demands for safety, quality, and manufacturing efficiency. This presentation will introduce advanced hydraulically operated formwork and robotic systems for cleaning, reinforcement placement, and surface finishing. Fully automated casting and vibration systems will also be highlighted as part of the state-of-the-art production process. These technologies reduce manual labor while enhancing consistency, sustainability, and segment durability. Drawing on global project experience, the presentation will explore how precision-engineered formwork systems are shaping the future of tunnel lining production through automation, quality control, and lean industrial processes.
Segment Production: The How, the Why, and What Really Matters
Presented By: Carlo Cattelan
Affiliation: Technopref Industries, Inc.
Description: This presentation offers a comprehensive look at segment production from the perspective of the people who live it daily—precaster production teams. It explores the full scope of production systems, emphasizing the critical inputs, outputs, and the reasons behind each step, offering insight valuable to Owners, Engineers, Contractors, and especially young engineers. More than just the "how," it dives into the "why"—highlighting what impacts precasters, the role of sub-suppliers, and ultimately, final segment quality. It also highlights where focus should be placed, what tends to be overemphasized, and how to better evaluate what is possible, what carries risk, and what drives cost.
Segment Manufacturing: The Devil Is in the Details – A Contractor’s Perspective
Presented By: Francois Renault
Affiliation: Vinci Construction Grands Projets
Description: This presentation illustrates the critical role of quality control in the manufacturing of precast tunnel segments. Through practical examples, it highlights how even minor oversights during production can lead to significant structural or functional failures in the field. Conversely, successful implementation of rigorous QC systems is shown to directly contribute to project performance, durability, and client satisfaction. Several real-world cases are used to demonstrate how overlooked process details often cause disproportionate downstream issues. The presentation emphasizes why a disciplined approach to manufacturing is essential from the contractor’s perspective.
Durability and Service Life Design of Precast Concrete Tunnel Linings
Presented By: Mehdi Bakhshi
Affiliation: AECOM
Description: This presentation addresses durability design strategies for precast segmental tunnel linings, targeting service lives of over 100 years. It outlines key degradation mechanisms in concrete—including corrosion, sulfate and acid attack, alkali-aggregate reactions, freeze-thaw cycles, and stray current corrosion—and how these affect material selection and segment detailing. Prescriptive approaches from North American concrete codes are compared with performance-based methods, including full-probabilistic service life modeling. Emphasis is placed on the role of concrete cover, mix design, supplementary cementitious materials (SCMs), and emerging technologies such as fiber reinforcement in enhancing long-term durability. The presentation also highlights how Monte Carlo simulations can inform reliability-based decisions in tunnel lining design under varying environmental and exposure conditions.