Robert G., South-East Regional Director in France* presents seismic safety regulations and related issues.
The context: In the world each year there are over one hundred and fifty earthquakes with magnitudes of 6 or higher (in other words earthquakes that release enough energy to be potentially destructive). The area of seismic safety is the subject of numerous regulations and obligations the world over. Every natural disaster brings better knowledge of the energies that can be released and sometimes gives rise to changes in “seismic zones”, as was the case with France and the new “zoning” brought in in 2009. Freyssinet provides an extensive range of solutions to meet seismic safety requirements for both new builds and repair.
What does Freyssinet offer in this area? We operate in two major fields: new builds and repair of existing buildings. – In the case of new builds, Freyssinet has developed appropriate seismic safety systems and offers a full range of dedicated products. • Dampers that absorb seismic energy (TRANSPEC® range) • Connectors that keep a structure firmly fixed to its foundations during an earthquake (TRANSPEC® Connector) • Bearing systems (elastic, visco-elastic, pendulum, etc.) • Shock absorbing cross bracing systems created with hydraulic or seismic safety dampers • Tuned mass dampers These various devices can be used alone or in combination to achieve the most effective and most appropriate protection for a particular construction project. Seismic protection is based on three fundamental operational modes which are: isolation, connection and dissipation. Every year numerous structures are built throughout the world incorporating these three protective methods. In addition, Freyssinet is launching its new ISOSLAB® foundation solution used to isolate a series of buildings or a district and minimise seismic acceleration in traditional construction works. ISOSLAB® is certainly the safest slab foundation solution around, useable in all risk areas (buildings, basements, streets, play areas, etc.) and serving to isolate the general public from the effects of earthquakes.
– In the case of existing buildings, Freyssinet operates at all phases of a project, both pre- and post-quake: diagnosis, studies and works. Freyssinet’s engineering & design and technical teams help clients make an initial diagnosis before deciding on how to strengthen structures and selecting the desired level of protection. The company can also intervene at the execution stage of the works our clients decide on.
In addition to the techniques described above, Freyssinet carries out seismic protection works based on two major intervention methods: • Strengthening, consisting in making the structure more resistant, or more ductile (examples of works carried out: buildings, bridges, nuclear plants, etc.) • Isolation, consisting in cutting into the structure at foundation level and then supporting it in order to insert a series of bearings that may or may not be connected to a damper Foreva® techniques and solutions, for example underpinning, additional prestressing and carbon fibre reinforcement, are frequently used, effective solutions for achieving compliance with seismic safety regulations and are a major competitive advantage in this market.
*The South-East Region is one of the French regions with the highest earthquake risk levels in the country, 4 out of a possible 5, and is very experienced in handling projects in this field.
