Abstract Summary
In recent years there has been an increasing demand for housing in developing countries such as Colombia. Therefore, a significant number of mid-rise residential buildings with thin RC shear walls have been built for low-cost construction requirements. These buildings have been constructed in areas of high and intermediate seismic risk such as Bogotá, the country’s capital city, where they represent 32% of its building stock. The main characteristic of this system is the reduced thickness of the walls, ranging from 100 to 150 mm, which results in high slenderness and low reinforcement ratios, reflected in reduced construction cost. These led to the use of welded wire mesh (WWM), as the main reinforcement in the core of the wall, which is a material with low ductility. Experimental studies have shown that currently available WWM do not meet the requirements to be used as reinforcement in concrete structures requiring intermediate or special energy dissipation. The main concerns are related to the lack of ductility, insufficient experimental information, scarce evidence on its behavior during earthquakes and lack of clarity of design guidelines in modern seismic-resistant codes that could lead to inadequate behavior of these buildings. This research aims to provide evidence by analyzing the structural behavior of a 6-story prototype building with reinforced concrete walls, located in Bogotá, Colombia and designed according to the requirements of the Colombian code. The modeling consists in a three-dimensional computational representation of the building in OpenSees using the Multiple-Vertical-Line-Element-Model (MVLEM) where the walls are connected through a multi-point constraint between floor nodes. This approach allows the simulation of flexure-dominated RC wall behavior. The performance is numerically evaluated by pushover and nonlinear dynamic analyses; the structural parameters are obtained from available information of the prototype and Colombian materials. In the dynamic analysis, records were selected with acceleration spectrum that reproduce the seismic hazard for the city of Armenia, considering different hazard levels and with occurrence rates assigned using the Conditional Scenario Spectrum (CSS) methodology. Different performance levels of the structure were analyzed with the results of the static analysis and compared with those available in the literature. The results show that the performance of the buildings is adequate in terms of system over-strength, which reaches a value of 2.6. On the other hand, once the maximum capacity of the structure is reached, its capacity decreases rapidly due to mesh rupture, which shows the low ductility of this type of material.
