In this episode, we talk to Anastasia Athanasiou, a Postdoc fellow in Structural and Wind Engineering at Concordia University about the performance-based multi-hazard design of buildings, and more specifically, the effects, similarities and differences of wind and earthquakes loads on buildings and how engineers can enhance the inherent resilience and improve the robustness of buildings.
Engineering Quotes:
Here Are Some of the Questions We Ask Anastasia:
In 2017 you were invited to present your work to the ‘1st Japan-Greece International Workshop by Young Researchers on Advanced Materials and Technology for Applications to Steel and Composite Steel/Concrete Structures’, in DPRI Kyoto University. Can you tell us what you presented there, and how that experience has benefited your engineering career?
What are some of the similarities, as well as differences of wind and earthquake loads and how they act on buildings?
What are some of the latest challenges you have seen in the wind design practice?
Why is it so important to do an earthquake risk assessment, and what does that involve?
You often hear engineers talk about a multi-hazard design. What that involves?
In your opinion, what kind of multi-hazard engineering strategies can be incorporated into the design to enhance the inherent resilience and improve the robustness of buildings?
What career advice would you give to young engineers who would like to achieve similar success as you did?
Here Are Some of the Key Points Discussed About Performance-Based Multi-Hazard Design of Buildings:
In 2017 I presented my work on earthquake protection systems to the '1st Japan-Greece International Workshop. The presentations focused on my PhD work that included data collected from a full-scale free vibrations task that was performed on a realm building in Sicily. It was a great opportunity because we got to meet many career researchers and masters’ students. We also visited some sites that were affected by the big 1995 earthquake. This event helped me to expand my knowledge and network in engineering tremendously.
Some of the similarities between wind and earthquake loads are that they are both accidental and lateral loads which means that you apply them as horizontal loads that act on the structure. Wind is essentially applied and conceived as an external force.
The way we perceive earthquakes is like inertia. An earthquake depends on the mass and stiffness of the structure and the acceleration of the earth. Wind loads depend primarily on the environment, location, size of the buildings, and the direction and velocity of the wind.
Seismic intensity is described as peak ground acceleration. Whereas wind intensity is described as velocity or velocity pressure. Seismic recordings show the acceleration time history of the ground which is described as a graph that moves above and below zero because of the cyclic loading inflicted on the structure. Wind speed recordings show a time history of normalized pressures oven a given time. The wind has a strong static component which means the average reading is not zero because the wind is causing the building to move in one direction. It is called the displaced equilibrium because wind gusts cause the graph to fluctuate around the displaced equilibrium, and not zero as in seismic events.
Earthquakes cannot be predicted but wind loads can be predicted by studying meteorological data, and warnings can be issued.
Earthquakes are replicated using shake tables on models, and even on full-scale structures. Winds are replicated in wind tunnels on models that are scaled down to three hundred or more times smaller than the original structure.
There is a lot of work that must still be done in wind engineering because it is still a young profession.
