ASSESSMENT OF A RETROFITTING TECHNIQUE FOR PERUVIAN CONFINED MASONRY DWELLINGS USING FRAGILITY FUNCTIONS

Quiroz L.; Maruyama Y. · World Conference on Earthquake Engineering proceedings (2021)

Resumen

A good seismic performance of dwellings in seismic-prone regions is very important because an inadequate behavior is the main cause of economic and human losses. A strategy to assess the seismic performance of structures is using fragility functions, which estimate the probable damage due to a seismic event. In Lima City, Peru, many low-rise dwellings are built with confined masonry (CM) walls because of the low cost. In our previous studies, an analytical approach was used to construct fragility functions to evaluate the seismic performance of low-rise dwellings whose vertical and lateral resistance systems consist of CM walls. It was found that two-and three-story CM dwellings are prone to high structural damage due to severe earthquakes. Based on the background, a simple retrofitt ing procedure used in Lima City is investigated and its effectiveness is evaluated by generating new fragility functions for the retrofitted dwellings. Because three-story CM dwellings have high probability of collapsing, it is not possible to retrofit these structures using a simple procedure. Therefore, the suggested retrofitting procedure is employed only for two-story dwellings. The procedure involves adding an electro welded wire mesh (EWWM) covered with mortar on both faces of the masonry panel. Numerical model of two-story dwellings is analyzed, and the properties of their main structural elements are defined based on the experimental results and numerical calculations. A series of nonlinear dynamic analyses are performed using simulated ground motion records for Lima City. The fragility functions for the original and retrofitted dwellings are constructed assuming that the damage ratios follow lognormal distributions. The results show that retrofitted dwellings accomplish the regulations stipulated by the E.030 Peruvian standard. Besides, the probability of damage is significantly reduced, and these structures can be constructed without gaps between adjacent dwellings.

Instituciones: Universidad Nacional de Ingeniería