Seismic Design of Tunnels - Parsons Brinckerhoff

FOREWORD
For more than a century, Parsons Brinckerhoff (PB) has been instrumental in
advancing state-of-the-art design and construction of underground structures, and the
fields of seismic design and earthquake engineering are no exceptions. Almost three
decades ago PB’s engineers pioneered in these fields in the design and construction of
the San Francisco BART system, whose toughness during earthquakes, including the
recent Loma Prieta event, has been amply tested. Recently, PB developed state-of-theart,
two-level seismic design philosophy in its ongoing Los Angeles Metro and Boston
Central Artery/Third Harbor Tunnel projects, taking into account both performance-level
and life-safety-level earthquakes.
This monograph represents PB’s continuous attempts in the seismic design and
construction of underground structures to:
• Improve our understanding of seismic response of underground structures
• Formulate a consistent and rational seismic design procedure
Chapter 1 gives general background information including a summary of earthquake
performance data for underground structures.
Chapter 2 presents the seismic design philosophy for tunnel structures and the
rationale behind this philosophy. Differences in seismic considerations between surface
structures and underground structures, and those between a seismic design and a static
design are also discussed.
Chapter 3 focuses on the seismic design considerations in the longitudinal direction of
the tunnels. Axial and curvature deformations are the main subjects. The free-field
deformation method and the methods accounting for tunnel-ground interaction effects are
reviewed for their applicability.
Chapter 4 takes a look at the ovaling effect on circular tunnel linings. Closed-form
solutions considering soil-lining interaction effects are formulated and presented in the
form of design charts to facilitate the design process.
Chapter 5 moves to the evaluation of racking effect on cut-and-cover rectangular
tunnels. This chapter starts with a review of various methods of analysis that are currently
in use, followed by a series of dynamic finite-element analyses to study the various factors
influencing the tunnel response. At the end, simplified frame analysis models are
proposed for this evaluation.
Chapter 6 ends this monograph with a general summary.
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