RC buildings constitute the prevailing type of construction in earthquake-prone region like
Kathmandu Valley. Most of these building constructions were based on conventional methods. In this
context, the present paper studied the seismic behaviour of existing RC buildings in Kathmandu Valley. For
this, four representative building structures with different design and construction, namely a building: (a)
representing the non-engineered construction (RC1 and RC2) and (b) engineered construction (RC3 and
RC4) has been selected for analysis. The dynamic properties of the case study building models are analyzed
and the corresponding interaction with seismic action is studied by means of non-linear analyses. The
structural response measures such as capacity curve, inter-storey drift and the effect of geometric nonlinearities
are evaluated for the two orthogonal directions. The effect of plan and vertical irregularity on the
performance of the structures was studied by comparing the results of two engineered buildings. This was
achieved through non-linear dynamic analysis with a synthetic earthquake subjected to X, Y and 45° loading
directions. The nature of the capacity curve represents the strong impact of the P-delta effect, leading to a
reduction of the global lateral stiffness and reducing the strength of the structure. The non-engineered
structures experience inter-storey drift demands higher than the engineered building models. Moreover,
these buildings have very low lateral resistant, lesser the stiffness and limited ductility. Finally, a seismic
safety assessment is performed based on the proposed drift limits. Result indicates that most of the existing
buildings in Nepal exhibit inadequate seismic performance.