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Liquefaction constitutes the most common source of seismic damage to buildings resting on saturated soils. Soil-structure interaction (SSI) may also significantly affect the seismic response of structures, modifying their dynamic characteristics and the seismic response at the foundation level. Although progress has been made on the investigation of the influence of soil liquefaction and SSI on the structural response, studies combining both phenomena are very limited. To bridge this gap, we investigate the integrated influence of both liquefaction and SSI on the seismic response and vulnerability of low-code reinforced concrete (RC) moment resisting frame buildings. A two-storey non-ductile RC frame building is adopted as reference. The following numerical models are developed: (1) a fixed-base structure subjected to free-field (FF) motion neglecting liquefaction (and SSI); (2) a fixed-base structure subjected to FF motion allowing liquefaction; (3) a flexible-base structure (i.e. including SSI) resting on soil subjected to outcrop bedrock motion neglecting liquefaction; (4) a flexible-base structure resting on soil subjected to outcrop bedrock motion allowing liquefaction. Conducting nonlinear incremental dynamic analysis for the above-described configurations, we derive seismic fragility curves considering (or not) SSI and/or liquefaction effects for different damage limit states through statistical correlation of the calculated engineering demand parameter with appropriate intensity measures. We also generate vulnerability curves to quantify the expected structural losses. Results show the substantive role of liquefaction and SSI in altering the seismic fragility and vulnerability of non-ductile low-rise RC frame buildings. [ABSTRACT FROM AUTHOR]

Greek classical temples constitute monuments of great historical and architectural value. The majority of them remain nowadays as free-standing multi-drum or monolithic columns or portals. Their present typology, in addition to their slenderness, render their response to seismic ground shaking quite distinct compared to that of modern structures. Rocking and/or sliding of the drums along their interfaces are the main modes of response under seismic loading. In this study, the seismic response of classical multi-drum columns is investigated by means of rigorous numerical analysis. An Ionic multi-drum column that has recently been restored at the Akropolis of Lindos in Rhodes, Greece, is used as a case study. The numerical analyses are performed using the finite element code ABAQUS. Numerical modelling is validated with a series of shaking table tests that were performed on a scaled multi-drum model column. Additional analyses are conducted by bonding perfectly the structural elements of the column, to investigate the seismic response of free-standing monolithic columns and compare with multi-drum columns of the same geometry. Through the presentation of representative results, critical parameters that affect the seismic response of this type of structures, including the amplitude and frequency content of the applied base excitation, the effect of uniaxial or multiaxial excitation and the interface characteristics, are highlighted and discussed. Particular emphasis is given on the stresses developed along the interfaces during shaking. The structural performance and overall stability of both the multi-drum and monolithic columns are investigated in terms of the maximum displacement of the capital against various intensity measures of the base excitation. The study contributes towards the improvement of the knowledge of the seismic performance of free standing rocking systems, such as the classical columns. [ABSTRACT FROM AUTHOR]

The present study focuses on the dynamic system identification of the Suleiman Mosque minaret in the medieval city of Rhodes, Greece. Suleiman Mosque was built in 1522 at the site of the destroyed Christian Church of the Apostles. First, we performed sets of ambient vibration measurements at the minaret of the monument. Based on these data, we calculated the eigenproperties of the minaret. Next, we modeled the monument in three dimensions, using the finite element method. Six numerical models were considered. Model Ι is the simplest one (isolated, fixed base minaret). Model VI is the most complicated one (simulation of the whole mosque also considering soil–structure interaction and foundation flexibility). The calculated predominant periods and mode shapes of Models I–VI are validated against the microtremor field measurements, recorded on the minaret's two floors and ground level. We elaborate on the reliability of finite element models for earthquake response evaluation, considering soil–structure interaction and foundation flexibility on the mode shape eigenfrequencies. Additionally, we discuss the seismic response of the minaret compared to the whole monument. We observed no significant difference in the first two modes of response, implying that the minaret's dynamic behavior is slightly affected by the entire mosque's presence. [ABSTRACT FROM AUTHOR]