Periodic meeting of the Society for Earthquake and Civil Engineering Dynamics - 23 February 2011 - London
Society for Earthquake and Civil Engineering Dynamics
The Society for Earthquake and Civil Engineering Dynamics (SECED) was founded in 1969 to promote the study and practice of earthquake engineering and civil engineering dynamics, and acts as a forum for professionals who need to keep abreast of the rapid developments in the field. SECED is the British branch of both the International Association and the European Association of Earthquake Engineering.
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The Society for Earthquake and Civil Engineering Dynamics (SECED) - Prof. Ahmed Elghazouli - is going to organize a meeting entitled "Performance Based Damage Assessment and Development of Nonlinear Retrofitting Devices for Masonry Buildings" on the 23rd of February 2011 (18:00) at the Imperial College London, South Kensingtonm Campus, Lecture theatre 201.
Speakers: Dr Dina D'Ayala & Eng. Sara Paganoni
The earthquake that occurred in L'Aquila Abruzzo in April 2009 was extremely damaging for the historic centres of the Region. Almost 2 years later most of the heritage buildings in the historic city centre of L'Aquila, whether major monument or ordinary residential buildings, are still far from having been repaired, and the hearth of the city looks more like a ghost town than the thriving commercial and cultural centre home to 70000 people that it used to be on the eve of April 6th 2009. Following the earthquake the presenters carried out two campaigns of survey with the aim of recording the damage to historic buildings, evaluating their vulnerability and validating a performance based approach to the development of fragility curves for this class of structures using the FaMIVE method, whereby feasible collapse mechanisms and the associate failure load factors can be identified.
In the first talk the procedure is briefly outlined and it is shown how push-over curves can be produced by statistical elaboration of FaMIVE's output. Validation is conducted by comparison with both the response spectrum derived by EC8 and the response spectrum for the main shock as recorded by the closest station to the city. Conclusions are drawn on the reliability of the FaMIVE method and its wider applicability. Results of the survey confirmed that the presence of metallic cross-ties can be crucial to preventing out-of-plane failures of unreinforced masonry walls. This traditional system, which is widely spread all over Europe and the Mediterranean basin, is indeed able to restore the box-like behaviour of historic buildings, otherwise affected by the poor performance or complete lack of connections between sets of perpendicular walls. Nevertheless, the localised increase of stiffness resulting from the insertion of ties in a weak substratum can cause damage such as pull-out or in-plane cracking. Drawing on these observations, the second talk presents the development of an innovative typology of anchors: a dissipative device is installed in series with a grouted stainless steel anchor at the joint of perpendicular walls, where out-of-plane cracking is most likely to develop. The presentation focuses on the experimental and computational validation of the devices. The discussion includes static and dynamic tests on the isolated devices and large scale tests of the anchoring devices embedded in low shear capacity walls. The relevance of using 3-D non linear finite element modelling to refine the development concludes the presentation.