LOAD-BEARING CAPACITY OF IMS FLOORS AFFECTED BY CABLE CORROSION

Abstract

IMS structures are skeletons assembled of precast concrete units, where floor units are connected to columns by post-tensioning. Ulterior tests show cables to exhibit significant corrosion in critical floor cross-sections. Variation of the failure risk of similar floor structures has been examined taking cable corrosion into consideration. Expected values of critical internal forces and load- bearing capacities of critical cross-sections have been deterrnined by probabilistic methods. Internal forces computation applied 2D and 3D lattice programs run on IBM 386 computer. According to test results on a typical floor constructed 15 years ago assuming corrosion as probabilized from disclosures, failure probabilities of critical cross-sections compared to the original condition much increased, exceeding by about two orders the Hungarian Standard requirement. According to investigations, if in a cross-section, cables of a given direction undergo total corrosion or rupture, internal forces are rearranged, leading to progressive collapse of the floor.