Kömürhan Highway Bridge is a reinforced concrete box girder bridge located on the 51st km of Elazığ–Malatya Highway over the Fırat River. Because of the fact that the Kömürhan Bridge is the only bridge in this part of Fırat, it has major logistical importance. So, this paper aims to determine dynamic characteristics such as natural frequencies, mode shapes, and damping ratios of the bridge using experimental measurements and finite-element analyses to evaluate current behavior. The experimental measurements are carried out by ambient vibration tests under traffic loads. Due to the expansion joint in the middle of the bridge, special measurement points are selected and experimental test setups are constituted. Vibration data are gathered from the both box girder and bridge deck. Measurement time, frequency span, and effective mode number are determined by considering similar studies and literature. The peak picking method in the frequency domain is used for the output-only modal identification. An analytical modal analysis is performed on the developed two- and three-dimensional finite-element model of the bridge using SAP2000 software to provide the analytical frequencies and mode shapes. At the end of the study, dynamic characteristics of the Elazığ and Malatya parts of the bridge obtained from the experimental measurements are compared with each other and transverse effects on the bridge are determined. Also, experimental and analytical dynamic characteristics are compared. Good agreement is found between dynamic characteristics in the all measurement test setups performed on the box girder and bridge deck and analytical modal analyses.
The main structural elements of historical masonry arch bridges are arches, spandrel walls, piers and foundations. The most vulnerable structural elements of masonry arch bridges under transverse seismic loads, particularly in the case of out-of-plane actions, are spandrel wall. The vulnerability of spandrel walls under transverse loads increases with the increasing of their length and height. This paper computationally investigates the out-of-plane nonlinear seismic response of spandrel walls of long-span and high masonry stone arch bridges. The Malabadi Bridge with a main arch span of 40.86m and rise of 23.45m built in 1147 in DiyarbakIr,Turkey, is selected as an example. The Concrete Damage Plasticity (CDP) material model adjusted to masonry structures, and cohesive interface interaction between the infill and the spandrel walls and the arch are considered in the 3D finite element model of the selected bridge. Firstly, mode shapes with and without cohesive interfaces are evaluated, and then out-of-plane seismic failure responses of the spandrel walls with and without the cohesive interfaces are determined and compared with respect to the displacements, strains and stresses.
The majority of historical masonry bridges were constructed early years and they were not originally designed to carry the extent of loads imposed on them by current vehicular traffic and seismic loads. Therefore, many existing masonry arch bridges can need reassessment and upgrading. In addition to arch elements, the most vulnerable structural elements of masonry arch bridges under transverse seismic loads are the spandrel walls. Spandrel wall failures are local failures, however they affect the serviceability of the bridge considerably. The present paper aims to determine transverse nonlinear seismic performances of the spandrel walls of masonry arch bridges strengthened with different techniques, which are i) take down and rebuilt with tapered section instead of straight section, ii) using transverse tie bars, and iii) covering with a Fabric Reinforced Cementitious Matrix (FRCM) composite. The concrete Damage Plasticity (CDP) material model adjusted to masonry structures for the masonry units, Mohr–Coulomb material model for the backfill, and interface interactions between the backfill, spandrel walls, arch and FRCM units are considered in the 3D finite element model of the bridge. Modal, nonlinear static and seismic responses of the spandrel walls strengthened with the above three different techniques are determined using the finite element method, and the results obtained from the unstrengthened and strengthened models are evaluated and compared with each other. Some recommendations are presented for the strengthening of the spandrel walls in masonry arch bridges.
The effect of the non-linear material behavior of a rock-fill dam subjected to random loads is investigated by the equivalent linear method that considers the non-linear variation of soil shear moduli and damping ratios as a function of shear strain. The Keban dam constructed in Elazig, Turkey is chosen as a numerical example. The interaction of the rock-fill dam with the reservoir is neglected, but not the foundation rock. The properties of the dam materials were taken from the dam project and assumed to be isotropic in the analysis. A stationary and ergodicity assumption are made for stochastic dynamic analysis. The E-W component of the Erzincan earthquake recorded on March 13, 1992, Erzincan, Turkey is chosen as a ground motion since it occurred nearby the dam site. The component considered is applied to the dam in the horizontal direction. The non-linear stochastic responses of the Keban dam are compared to its linear stochastic and deterministic response.
This research presents finite element modelling, vibration-based operational modal analysis, and finite element model updating of a restored historic arch bridge. Mikron historic bridge, constructed on Fırtına River in Rize, Turkey, is the subject of this case study. The General Directorate for Highways of Turkey repaired the bridge's main structural elements, arches, sidewalls, and filler material in 1998. To construct a 3D finite element model of the bridge, ANSYS finite element software estimated the analytical dynamic characteristics. Induced ambient vibrations such as human walking and wind excited the model bridge to allow measurement of the bridge's responses. Enhanced frequency domain decomposition in frequency domain and stochastic subspace identification in time domain methodologies extracted experimental dynamic characteristics. A comparison of the analytical and experimental results showed significant agreement between mode shapes, but some differences in natural frequencies appeared. Consequently, updating the finite element model of the bridge by changing boundary conditions minimised the differences between analytical and experimental natural frequencies. After the finite element model updating process, the differences between natural frequencies declined from 7% to 2%.
Masonry arch bridges, which were generally built using brick and stone materials, still form a significant part of the highway and railway networks in the World. The subsoil deformability may considerably affect seismic damage mechanics of masonry arch bridges. The paper investigates the effects of nonlinear foundation soil behavior on the seismic damage mechanisms of brick and stone semicircular masonry arch bridges. Direct soil-structure interaction (SSI) approach is taken into account in the 3 D finite element models of the masonry arch bridge-foundation-soil interaction systems including contact, finite and infinite elements. Nonlinear behaviors of masonry units and homogenous soil domain are modeled using the Concrete Damage Plasticity (CDP) and Mohr-Coulomb failure criteria. The selected ground motion is matched and deconvoluted for hard and medium soil domains. Seismic damage mechanisms of brick and stone masonry arch bridges subjected to combined longitudinal and vertical deconvolved ground motion components are obtained for hard, medium, and partially hard and medium soil domains and are compared with each other.
In the present paper it is aimed to perform the stochastic dynamic analysis of fluid and fluidstructure systems by using the Lagrangian approach. For that reason, variable-number-nodes twodimensional isoparametric fluid finite elements are programmed in Fortran language by the authors and incorporated into a general-purpose computer program for stochastic dynamic analysis of structure systems, STOCAL. Formulation of the fluid elements includes the effects of compressible wave propagation and surface sloshing motion. For numerical example a rigid fluid tank and a dam-reservoir interaction system are selected and modeled by finite element method. Results obtained from the modal analysis are compared with the results of the analytical and numerical solutions. The Pacoima Dam record S16E component recorded during the San Fernando Earthquake in 1971 is used as a ground motion. The mean of maximum values of displacements and hydrodynamic pressures are compared with the deterministic analysis results.
This research is motivated by post-earthquake observations of significant structural damage to minarets during the 2023 Kahramanmaraş earthquakes. It is thought that the near-fault velocity pulse-like ground motions played a crucial role in this phenomenon. Although the seismic performance of minarets has been extensively studied, including a large body of literature on numerical and experimental analyses, no attention has been paid to the seismic damage assessment of minarets subjected to strong velocity pulse-like ground motions. The present study aims to investigate the effects of near-fault strong velocity pulse-like ground motions with different velocities on the seismic failure behavior of masonry minarets. A 33-meter-high stone masonry minaret was selected for this purpose. Nonlinear behavior of masonry unit is modeled using Concrete Damage Plasticity (CDP). For the nonlinear analysis, three near-fault strong velocity pulse-like ground motions recorded during February 6, 2023, Kahramanmaraş earthquake (M7.7) and one non-pulse-like ground motion were selected. Displacements, strains, stresses and damage patterns in masonry minarets subjected to near-fault velocity pulse-like and non-pulse-like ground motions were obtained and thoroughly evaluated across different ground velocities. The velocity, the number of pulses and the pulse duration of velocity-pulse-like ground motions have a significant influence on the structural damage behavior of minarets. The results provide a detailed understanding of how minarets respond to different velocity pulse-like ground motion scenarios, offering valuable insights for the design, rehabilitation, and retrofitting of both new and existing minarets.
This paper illustrates the damages of reinforced concrete and masonry minarets during October 23 (Erciş) and November 9 (Edremit), 2011 Van earthquakes in Turkey. Erciş and Edremit are townships located 90km and 18km from Van city center in Turkey, respectively. Ground accelerations and response spectrums for these earthquakes are given in this paper. A total of 63 reinforced concrete and masonry minarets are heavily damaged or collapsed in the city center and villages nearby after both earthquakes. Because of the fact that there is no Turkish standard and specification directly related to design of minarets, nearly all of the constructions are carried out by workers using only their own technical knowledge. So, all of the non-engineering reinforced concrete and masonry minarets completely collapsed or damaged heavily. From the study, it is seen that the damages are due to several reasons such as site effect, location, and length of the fault, reduction in cross section and formation of the discontinuity, use of plain reinforcement steel, use of concrete with insufficient strength, existence of short lap splices and incorrect end hook angle, larger mass and stiffness concentrations on some region, longitudinal reinforcements discontinuity, cracks at the cylindrical body, and damage of spire and end ornament. In addition to these reasons, the two earthquakes hit the minarets within seventeen days, causing progressive damage. So, the existing design and construction practices should be improved to provide sufficient earthquake performance. Also, it is recommended that there should be a safe distance between the minaret and surrounding structures to reduce the loose of life after earthquake.
