摘要：Puerto Rico is situated in an earthquake prone region. Because of the imminent
risk of being affected by a strong earthquake, it is important to study the
damage vulnerability of existing structures in the Island. This study is
directed to medium rise concrete residential buildings in Puerto Rico. Most
of multistory residential buildings in Puerto Rico are reinforced concrete
structures with lateral resisting system composed by shear walls oriented in
both directions. The lack of local earthquake vulnerability curves for Puerto
Rico and the fact that local construction practice differs from that in USA
motivates the author to look at the development of reliable fragilities curves
based on typical buildings properties and selection of ground motions based
on local geology characteristics and past worldwide earthquakes scaled to
different peak ground acceleration to obtain a wide range of maximum
accelerations. The analytical models are two-dimensional and are analyzed using
the nonlinear dynamic time history method considering both flexural and shear
nonlinear behavior for shear walls. Algan’s formulation (1982) and HAZUS
drift limits were used to calculate the expected damage of the models. Damage
of the structures is quantified based on the inter-story drift ratio of
the structure. The damage states considered were: Minor, Moderate,
Substantial and Major, for Algan and Slight, Moderate, Extensive and Complete
for Hazus. With this information, lognormal functions expressed in the form
of two parameters (log-median and log-standard deviation) were fitted
and fragility curves developed as a function of PGA. A set of four fragility
curves, one for each damage state is developed for each scenario studied.
These curves are useful tools for the insurance companies in Puerto Rico in
order to improve their risk assessments.
