This workshop will cover recent advances in the Canadian seismic bridge code and in the practice of seismic design for geotechnical, structural, and system-level performance of bridges in Canada. The latest code requirements influencing bridge seismic design from concept to details, and how to analyse and design bridge seismic systems based on four structural/geotechnical approaches under a performance-based design philosophy as laid out in CSA S6:25 (CHBDC).  Principles and strategies as applied to new bridges and bridge retrofit, along with decision-making, will be discussed.  It will also discuss possible directions in seismic design for the coming (S6:30) code cycle.

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The workshop will illustrate geotechnical, structural, and network damage experienced in recent earthquakes, and ask participants to interpret geotechnical and structural damage from a seismic performance-based objectives perspective.  It will discuss component-level, bridge system-level and network-level damage measures, which will assist both owners and designers.  It will outline the key updates to CSA S6:25 relative to S6:19, including the use of 6th generation seismic hazard, features, and limitations of current hazard models, and how to analyse seismic inputs to bridge-foundation systems. Geotechnical engineering content will include site classification, application of hazard, modelling abutments (regular and integral) and walls for displacement-consistent soil pressures, design of shallow and deep foundations, and rapid and effective implementation of soil-structure interaction and design requirements for geotechnical system design.

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Structural engineering content will cover simple analysis models predicting and checking peak responses, full response spectrum design, force-based (ductility) design, performance-based design, including details of the application of static pushovers, strain, and damage measures. It will discuss component-level damage measures vs bridge system measures for improved designs.  Importantly, it will illustrate the application of elastic strength-based design, which has been included more explicitly as a low-damage seismic system and which was often confused as an “out” in cases where capacity design demands became impractical. It will cover updates to capacity design and expected material properties, including new rebar grades, and the differences between RSA-based modeling for demands and substitute structure methods, which underpin direct displacement-based design.