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The material properties of steel and concrete vary depending on the loading rate to which they are subjected. To realistically evaluate the seismic performance of reinforced concrete (RC) columns, it is necessary to simulate the loading rate that structures will experience during seismic events as accurately as possible. Real‐time dynamic testing is preferred over quasi‐static testing for this purpose. On the other hand, the seismic performance of RC columns also depends on the axial force applied to the column. However, due to the large axial stiffness of RC columns, accurately controlling the axial force during the test, particularly in real‐time testing, is challenging. Consequently, only a few component‐level dynamic tests have been conducted for RC columns. This study aims to explore the influence of axial force and loading rate on the seismic performance of RC columns. To this end, both slow and fast cyclic loading tests were conducted on square cross‐section RC columns subjected to four different axial forces. By utilizing a robust actuator control method along with a specially designed load transfer element, the axial force was successfully controlled, while the lateral displacements were imposed on the columns in real‐time. The results include lateral strengths, postyield responses, damage patterns, rebar strains, and their rates, all of which constitute unique experimental data that can contribute to a deeper understanding of the actual seismic response of RC columns. [ABSTRACT FROM AUTHOR]

A network interface program for controllers (NICON) for pseudo-dynamic hybrid simulations is presented. The program is implemented as an independent program residing between the simulation model and an actuator controller with various functions necessary for hybrid simulations, such as communication, coordinate transformation, error compensation. These functions are generalized to allow for a generic configuration of actuator setup theoretically with any number of control points and control degrees of freedom. Application examples of NICON to hybrid simulations of civil infrastructures subjected to earthquakes or fire are presented. [ABSTRACT FROM AUTHOR]

Design of embedded pipelines in seismic areas require consideration of the interaction between pipeline and surrounding soil. The soil‐pipe interaction is often numerically modeled using Winkler springs, where a simple bilinear or trilinear soil resistance‐displacement relationship is employed. As Winkler spring modeling approach requires experimental data for calibration of spring parameters, extensive experimental studies have been carried out. However, most tests in previous studies have been carried out for pipeline specimens subjected to monotonic load, in which pipe lateral‐vertical response coupling is hardly investigated. In the present research, a novel test method that enables testing of a pipe specimen under lateral or vertical cyclic loading is investigated. In the proposed method, a soil box is mounted on a 6‐degree of freedom (DOF) displacement‐controlled table, such that soil‐pipe interaction in the lateral/vertical direction can be investigated. A series of tests considering various parameters such as pipe diameter, burial depth, soil density, and loading condition were performed. Test results provided evidence of the effect type of loading has on soil‐pipe interaction and the strong coupling between pipe response along lateral and vertical directions. [ABSTRACT FROM AUTHOR]

Summary: In a building subjected to seismic loading, large compressive force may develop in reinforced concrete (RC) coupling beams because of axial restraint imposed by the neighboring shear walls against the elongation of the coupling beams during the failure process. The axially compressive force can increase the shear stiffness and strength of the coupling beam and may change its failure mode. In this paper, a novel coupling beam testing procedure adopting hybrid simulation method is proposed in which the axial restraint is determined through hybrid simulation and the calculated axial restraint is imposed on a specimen during the test. RC coupling beams were tested by adopting both the proposed test procedure and the conventional testing approach in which the effect of the axial restraint is not accounted for. Test results depict a clear difference in the response of the coupling beam, such as shear capacity and failure mode, depending on the consideration of the axial restraint during the test. The test outcome demonstrates the usefulness and applicability of the proposed test procedure. [ABSTRACT FROM AUTHOR]