Influence factors for the assessment of maximum lateral seismic deformations in Italian multistorey RC buildings

n the aftermath of low - to - moderate earthquakes, simplified methods allowing fast estimate of maximum lateral deformations experienced in multistory building are particularly useful when estimating nonstructural damage on a large building inventory. In particula r, Miranda [1] introduced a simplified method that adopts an equivalent continuum elastic structure to estimate both maximum roof displacement and maximum interstorey drift ratio for a given response spectrum. Based on a closed - form solution, this method was further ex- tended [2] to account for higher vibration modes, different distributions of lateral forces and non - unif orm stiffness along the height . However, the method assumes that building propert ies will continuously vary along the height, assumption that is not generally valid for the Italian building stock due to the pr esence of knee beams and infill panels . This paper investigates on the effect of variation of infill properties on the elastic l ateral response of infilled RC build- ings, assessing the influence of different characteristics, such as geometric and material properties or the opening percentage, on IDR max . Plane Multi - degree - of - freedom elastic mod- els including explicit modeling of infi ll panels are adopted and the effect of local discontinui- ties is included, while linear time - history analyses are performed considering several input ground motions. The effect on the interstorey drift ratio of different opening percentages and infill arra ngements , both at the same storey and along the height , are considered to account for discontinuities caused by the presence of infills . F urther, the influence of different types and thicknesses of the infill panels, level connection to the surrounding fra me is analyzed.