Influence of soil-structure interaction on dynamic inelastic response of planar steel frames G. D. Hatzigeorgiou(1), G. A. Papagiannopoulos(2), N. G. Pnevmatikos(3) (1) Hellenic Open University, School of Science and Technology, GR-26335, Patras, Greece, hatzigeorgiou@eap.gr (2) Department of Civil Engineering, University of Patras, GR-26500, Rio, Greece, gpapagia@upatras.gr (3) TEI of Athens, Department of Civil Engineering, Surveying & Geoinformatics, GR-12210, Athens, Greece, pnevma@teiath.gr