Publication:

In-plane Behavior of Reinforced Concrete Shear Walls with poor Flexural Reinforcement, Strengthened with FRP strips

There is a large amount of thin wall buildings in the country that have been constructed on inadequate designs, have extended their service life or have had changes in the type of use in structures, among other factors. Under these circumstances, these constructions have a high degree of vulnerability. This, added to the important seismic threat present in cities with the highest number of inhabitants, results in a risk of significant damage to buildings, which could even collapse. This research tested a system that could allow to repair or rehabilitate the walls of these buildings, using non-invasive systems like Fiber-reinforced polymers (FRP). FRP are an emerging repair or rehabilitation alternative that in recent years has become very popular. External reinforcement with FRP bands improves the bending and shear capacities of existing structures. This reinforcement system is even suitable for repairing structures with insufficient or degraded capacities after its elements had been subjected to seismic stresses. This document presents the results obtained in a research project that evaluated the behavior of reinforced concrete walls with vertical reinforcement deficiencies. The walls were externally reinforced with different types of FRP bands to improve their flexural capacities. 6 specimens of 0.1 x 1.5 x 5 m (4 x 59 x 197 in) were analyzed: 4 with concrete with low compressive strength and 2 with concrete with high compressive strength. The latter were externally reinforced with two types of carbon fibers (CFRP): one with a high elastic modulus (CHM) and another with a lower elastic modulus (CHS) and a type of fiberglass (GHS). The failure mode, hysterical response, stiffness degradation, ductility and energy dissipation capacity were evaluated. The bending capacities of the walls reinforced with each of the FRP bands showed an important improvement. Finally, the design methodology and calculation of theoretical capacities for this type of reinforcement, present in document ACI 440.2R-17, was corroborated. Thus, it was found an adequate correlation between the experimental results and the capacities theoretically calculated.