In reinforced concrete structures under\ud seismic loading, concrete is subjected to compressive cyclic stress. Although cyclic stress–strain response has been described before, the cyclic behavior of strains in the direction orthogonal to loading has not\ud been characterized yet. Such behavior can be of great importance for evaluating the efficiency of the confinement under cyclic loading. For this purpose an experimental program on cylindrical specimens of concrete strength from 35 to 80 MPa subjected to\ud uniaxial cyclic compression was carried out. Stress versus longitudinal and lateral strains curves have been obtained both for the hardening and softening branches under monotonic and cyclic loading. Governing\ud parameters of the lateral behavior are identified and correlated to describe the response of the lateral strain. Additionally, an analytical model to obtain the lateral deformations of concrete under cyclic uniaxial compression has been formulated and verified experimentally.\ud Finally, some examples are presented in\ud order to illustrate the applicability of the proposed model and its possible incorporation into a 3D constitutive cyclic model.Peer ReviewedPostprint (published version

Under general seismic loading, reinforced concrete columns may be subjected to lateral loads in more than one direction. Available experimental data on columns subjected to bidirectional forces indicate that higher levels of damage and a higher loss of ductility and strength have been observed compared to similar tests under unidirectional shear forces. In this study, an experimental program was conducted in which six lightly reinforced concrete columns were subjected to unidirectional and bidirectional cyclic shear forces. This observation was used to identify the mechanisms and parameters governing the behavior of columns subjected to cyclic bidirectional lateral loads. Hence, a new conceptual model was developed to obtain the capacity of member. The shear forces were analyzed and an analytical formulation was derived to account for the effects in the concrete stress-strain relationship, the moment-curvature diagram and the plastic hinge length. These equations were used along with a structural model with concentrated plastic hinges to obtain the capacity curve of the column. The results of the formulations developed were verified using the results of the experiments performed on columns subjected to unidirectional and bidirectional cyclic lateral forces.Peer ReviewedPostprint (author's final draft

<p>The use of prestressed concrete (PSC) box girder bridges built by segmentally balanced cast-in-place cantilevers has spread massively due to noticeable advantages over traditional. However, excessive deflections have been observed in 10-years old constructed bridges worldwide which have been designed based on old international code standards that underestimated rheological effects. To guarantee 100-year design life of bridges, it is necessary to have a periodic monitoring system that validates in-service performance. In Colombia there is a necessity to study in-service performance of this type of bridges after its construction, which is the main solution for structures with spans ranging from 80 m to 200 m, therefore this study seeks to propose a procedure to estimate the long-time behavior of box girder bridges in Colombia considering construction data scarcity. Therefore, altimetry data measured from a newly constructed bridge is collected, and the rheological effects of the structure are predicted using models previously developed and validated. Finally, a comparative analysis is carried out and guidelines are provided to propose a practical monitoring framework that guarantees adequate in-service bridge performance.</p>

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