Seismic resilience - our latest thinking

Seismic strengthening, increasing buckling capacity and reducing costs of retrofitting: Beca technical experts share their latest thinking at the 16th World Conference on Earthquake Engineering (WCEE) in January in Santiago, Chile.

Five of our structural engineers co-authored and presented papers on the following topics:

Application of a recently proposed displacement-based assessment procedure for plan asymmetric reinforced concrete wall buildings (Matt Fox, Senior Structural Engineer).

A new seismic assessment procedure developed for asymmetric-plan reinforced concrete wall buildings is examined and applied to an eight-storey case-study building. Matt discusses the merits and drawbacks of the new approach and its appeal for further inquiry.

Performance-based seismic assessment: Simplified methods and collapse indicators (Kam Weng Yuen, Associate – Structural Engineering).

Challenging some of the fundamental concepts in performance-based seismic assessment, this paper argues that by using simplified analysis methods and assessment of collapse indicators to determine likely building behaviour and the governing inelastic mechanism – an informed decision can be made of the implied seismic risk and required seismic strengthening.

Out-of-plane buckling behaviour of buckling-restrained brace (BRB) gusset plate connections (Ben Westeneng, Structural Engineer).

A proposed model of beam-column joint, gusset plate, connection region and the encased portion of the BRB is used to determine global stability of the BRB system, and prevent out-of-plane sway buckling of the gusset plate. Ben discusses how increasing gusset plate stiffness / decreasing BRB end rotational stiffness can increase / diminish buckling capacity.

Assessment and restoration of an earthquake-damaged sports stadium in New Zealand (David Whittaker, Senior Technical Director).

This paper looks at the damage that occurred to The Lancaster Park Stadium in Christchurch (a modern reinforced concrete design) as a result of the 2010/2011 Canterbury earthquakes. David discusses the engineering assessments that were carried out, and the likely scope of repairs to the remaining stadium structures and their foundations.

Multi-objective loss optimisation of seismic retrofitting of moment resisting frames using viscous dampers (Arun Mankavu-Puthanpurayil, Structural Engineer).

This paper discusses how a gradient based multi-objective framework can be applied to optimally quantify and distribute viscous dampers for retrofitting a building to reduce earthquake-induced vibration. The proposed procedure provides a practical trade-off between the initial upfront cost involved and the long-term economic impact of this design in the form of minimizing the total expected seismic loss. The framework gives stakeholders a clear picture of how much loss can be expected in an earthquake for a specific quantity of dampers added to the building.

Arun Mankavu-Puthanpurayil and David Whittaker also co-authored two other papers presented at the conference, including:

Organised by the International Association of Earthquake Engineering, the WCEE is held every four years and attended by scientists, engineers, architects, planners and policy officials interested in promoting earthquake risk reduction.

The conference offered a stimulating environment for the global exchange of knowledge, ideas, research results and practical experience, with topics ranging from seismic resilient cities and performance-based design, to geotechnical engineering and lessons from recent earthquakes.

For more information visit www.16wcee.com.

See also