An integrated Terrestrial Laser Scanner (TLS), Deviation Analysis (DA) and Finite Element (FE) approach for health assessment of historical structures. A minaret case study

Lesson learned after the Emilia-Romagna, Italy, 20–29 May 2012 earthquakes: A limit analysis insight on three masonry churches

Minarets are very slender structures with an old existence. The historical ones are made of cut-stone-block masonry assembled in peripheral cylindrical wall with an interior helicoidal stair supported on a central core and on the wall. They are spread throughout the Islamic world and constitute an important heritage not only of religious value, but also of great cultural interest. Throughout the times, these structures as part of a mosque, have suffered significant damage during the earthquakes. Istanbul presents interesting characteristics to evaluate their dynamic behavior, as they are in great number, in an area where a large event in the next 30 years has been predicted.

In this paper, we performed a series of in situ ambient vibration tests to old minarets of various sizes and compared results of frequencies with numerical modeling of the same structures. For the low-amplitude motion, the frequency values of the first modes can be obtained from an empirical formulae function of the inertia of the cross-section and of the height of the main ‘body.’ Damping ratios for these amplitudes are of the order of 0.5–1.0%.

Dynamic linear analyses of these structures indicate that for most cases very high stresses develop for PGA above 0.5 g, an input with a reasonable chance of occurring in the next 30 years. These high stresses are expected to cause the toppling of the minarets in the form that has been observed in the recent past events. Copyright © 2011 John Wiley & Sons, Ltd.

Minaret behavior under earthquake loading: The case of historical Istanbul

Operational modal analysis and FE model updating of the Metropolitan Cathedral of Santiago, Chile

Structural performance of the historic and modern buildings of the University of L’Aquila during the seismic events of April 2009☆

Damages of masonry buildings during the July 2, 2004 Doğubayazıt (Ağrı) earthquake in Turkey

This paper describes a historical masonry minaret, its finite element modeling, modal testing, and finite element model calibration. Iskenderpasa historical masonry minaret located in Trabzon City Center, Turkey, is selected as an application. Modal analysis is performed on the developed 3-D finite element model of the minaret to obtain the analytical frequencies and mode shapes. The ambient vibration tests on the minaret under environmental excitations, such as traffic loads and wind, are conducted. The output-only modal parameter identification is carried out by using peak picking of the average normalized power spectral densities in the frequency domain and stochastic subspace identification in the time domain. Dynamic characteristics such as natural frequencies, mode shapes, and damping ratios are determined. The finite element model of the minaret is calibrated to minimize the differences between analytically and experimentally estimated modal properties by changing some uncertain modeling parameters such as material properties and boundary conditions. At the end of the study, maximum differences in the natural frequencies are reduced on an average from 27 % to 5 %. A good agreement is also found between analytical and experimental natural frequencies and mode shapes after model calibration.

Modal Analysis, Experimental Validation, and Calibration of a Historical Masonry Minaret

This paper reviews the performance of stone masonry buildings during the March 25 and 28, 2004, Askale (Erzurum) earthquakes Askale is a township located 35 km from Erzurum city in Turkey A majority of the buildings in the affected region are built in masonry Most of the masonry buildings were formed with random or coursed stone walls without any reinforcement supporting heavy clay tile roofing over wooden logs A large number of such buildings were heavily damaged or collapsed The cracking and failure patterns of the buildings are examined and interpreted relative to current provisions for earthquake resistance of masonry structures The damages are due to several reasons such as site effect, location, and length of the fault, and the poor construction quality of the buildings In addition to these reasons, the two earthquakes hit the buildings within three days, causing progressive damage Low strength stone masonry buildings with mud mortar are weak against earthquakes, and should be avoided in high seismic zones

Performance of Masonry Stone Buildings during the March 25 and 28, 2004 Aşkale (Erzurum) Earthquakes in Turkey

Geophysical surveys could contribute significantly to remediation programs for damaged buried engineering structures. Resistivity profiling and mapping techniques used in this work allow rapid and one of the most cost-effective ways of characterization and visualization of internal defects of drainage and watering systems of football playgrounds in a nondestructive way. Cost-effective and nondestructive testing can be valuable assets for diagnosis, realization, and restoration of football playgrounds.

Nondestructive Electrical Resistivity Method to Map the Drainage System of Football Playgrounds

The single-station Rayleigh surface wave group velocities and electrical resistivities are two data sets that we cooperatively employ to image the near surface (< 40-m) anomaly structures. We numerically simulate the corresponding field measurements where the anomaly structures are assumed to have two-dimensional (2D) variations. The surface waves are represented by fundamental mode dispersion curves, and the electrical resistivities are assumed to be measured by using direct currents. We consider two types of anomaly structures, i.e., cavity and ore body. These two heterogeneities are easily distinguished from the surrounding geomaterial by their distinct physical properties. The cavity is characterized by low seismic velocity and high electrical resistivity, while the ore body is characterized by high seismic velocity and low electrical resistivity. The Rayleigh surface wave data is assumed to be collected throughout the classical common-shot gather. Multiple electrodes, multiple core cables, and multiple arrays are assumed to be used in the electrical survey. Both surface wave group velocities and electrical resistivities are shown to properly invert the anomalous structures in the subsurface. The surface wave group velocities have good horizontal resolution, while the corresponding vertical resolution is somewhat lower. The electrical resistivities have good resolution for shallow structures, but the resolution becomes somewhat reduced with increasing depth. Doi: 10.28991/HEF-2022-03-01-01 Full Text: PDF

Nart Coşkun

Papers

Damages of masonry buildings during the July 2, 2004 Doğubayazıt (Ağrı) earthquake in Turkey

Modal Analysis, Experimental Validation, and Calibration of a Historical Masonry Minaret

Performance of Masonry Stone Buildings during the March 25 and 28, 2004 Aşkale (Erzurum) Earthquakes in Turkey

Nondestructive Electrical Resistivity Method to Map the Drainage System of Football Playgrounds

Dispersion of Rayleigh Surface Waves and Electrical Resistivities Utilized to Invert Near Surface Structural Heterogeneities