This study investigates the pounding phenomenon by shaking table experiments on two scaled building models. Representing the situation where the seismic gap is insufficient, two building models are adjacently positioned on the shaking table, and pounding was investigated for harmonic and strong ground motion excitations. Displacement and acceleration responses were obtained to observe the pounding effect experimentally from video and accelerometer recordings, respectively. The Kelvin-Voigt Model consisting of spring and damper was used for numerical pounding analysis. The most critical parameters of the Kelvin–Voigt model, which are the spring stiffness (ks) and the damping, are calculated according to the coefficient of restitution (r) and were investigated and compared with harmonic experimental results. The obtained parameters, compatible with the harmonic experiments, were used to examine structural behavior under earthquake effect for the case where the building models are positioned for an insufficient seismic gap. For comparison, numerous numerical simulations were realized using different spring stiffnesses and coefficients of restitution. The study shows that when the coefficient of restitution is taken as 0.2 or 0.4, and the ratio of spring stiffness to shear stiffness (ks/k) is 1 or 5, reasonable results in numerical earthquake simulations can be obtained.

The structural safety of minarets is a critical issue, as their collapse during earthquakes poses severe risks to human life and nearby structures. However, there are no regulations considering their unique structural behavior. In the present study, this unique behavior is investigated by a comprehensive field reconnaissance conducted on masonry and RC minarets affected by the February 6, 2023, Kahramanmaraş Earthquakes. This investigation focused on identifying the underlying causes of minaret damage and collapse, with particular attention to failure mechanisms, material deficiencies, structural design shortcomings, and detailing weaknesses. In addition to the recorded high ground accelerations, the study revealed that the causes of minaret collapse and damage were widespread structural defects and design practices that inadequately reflect their unique seismic behavior. Furthermore, on a representative masonry minaret model, modal and time-history analyses were performed to investigate dynamic behavior. Another noteworthy finding highlights that near-fault effects are significantly influential in the collapse direction of RC minarets. Finally, design suggestions for future regulations specialized for the structural behavior of minarets and mitigation strategies are presented, to prevent similar damage and collapses in future earthquakes.

Shaking tables are frequently used to determine the dynamic behavior of structures in the laboratory environment. In order to obtain realistic results in experimental studies, table response and performance should be consistent with the desired motion. In this multidisciplinary study, an application of a new method for determining and calibrating the mechanical response of a developed bi-axial displacement controlled shake table according to the desired motion data is presented. The bi-axial shake table's electro-mechanical components consist of stepper motors, ball screw sets, linear ball bearings, and linear potentiometers positioned on both axes for displacement measurements. For the control and data acquisition (DAQ) unit of the shake table, an open-source electronic prototyping platform Arduino was used. From several experimental results, it was seen that, with the presented calibration method, harmonic and earthquake simulations could be achieved with a relative root mean square error (relative RMS error) of less than 5% for desired displacement-time histories.