International Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166921420191101Some Contribution to Rational Design of Piled Raft Foundation for Oil Storage Tanks on Non-Liquefiable Ground: Application of Dynamic Centrifuge Modeling1924331310.48303/jsee.2019.243313ENSeyed Mohammad SadeghSahraeianShiraz University of TechnologyJiroTakemuraDepartment of Civil and Environmental Engineering, Tokyo Institute of
TechnologyJournal Article20200204Some level of settlement is allowed in the design of oil tanks if uneven settlement is<br />controlled within allowable values. Considering the critical condition of Piled Raft<br />Foundation (PRF), that is, secure contact of raft base to the ground surface, PRF is<br />considered as one of the rational foundations for the oil tanks. However, PRF has a<br />complicated interaction with soil under horizontal seismic loading. Regarding this<br />complexity, the main concern in use of PRF for oil tanks is proper design of<br />this foundation system. In this study, a series of centrifuge tests were performed to<br />investigate the mechanical behavior of oil tanks supported by PRF on non-liquefiable<br />sand. Using the observed results, such as accelerations of the tank and ground<br />and displacements of the foundation, some practical hints for reasonable design of<br />piled raft foundation for oil tanks on non-liquefiable sand are discussed. According<br />to the results of this study, the main concern in the rational design of the foundation<br />is piles' design and their punching effect on the raft, in case of PRF of oil tank on<br />non-liquefiable sand.https://www.jsee.ir/article_243313_6afd6a9a246f8e20809f0dcc854303e2.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166921420191101Buckling Response and Elastic Stiffness of Butterfly Dampers112024331210.48303/jsee.2019.243312ENBehrokhHosseini HashemiStructural Engineering Research Center, International Institute of
Earthquake Engineering and Seismology (IIEES)BabakKeykhosrokianyStructural Engineering Research Center, International Institute of
Earthquake Engineering and Seismology (IIEES)Journal Article20200223Butterfly dampers dissipate energy through the flexural, shear, or axial response of<br />the strips when the device is subjected to inelastic cyclic deformation. The buckling<br />response, elastic stiffness, and cyclic performance of non-uniform steel butterfly<br />dampers have been studied in this paper. Validated material and geometric nonlinear<br />finite element models in the ABAQUS has been used to perform a comprehensive<br />parametric study on a wide range of geometrical parameters to evaluate the<br />response of non-compact butterfly dampers. The results showed that although the<br />low-cycle-fatigue response of butterfly dampers can be improved by altering the side<br />edge shapes, the buckling capacity and elastic stiffness of non-uniform strips would<br />decrease in comparison with uniform ones. Hence several analytical equations were<br />provided to quantitative prediction of the buckling capacity and elastic stiffness of<br />butterfly dampers.https://www.jsee.ir/article_243312_15909b79b75425397298da722e80c3c2.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166921420191101Modification of Park-Ang Damage Index to Accommodate Effect of Aftershocks on RC Structures213524331110.48303/jsee.2019.243311ENMortezaBastamiInternational Institute of Earthquake Engineering and Seismology (IIEES)0000-0002-7133-0977BehrouzEbrahimiUniversity of KurdistanJournal Article20200607Seismic design codes do not consider the effects of aftershocks on structures.<br />Moreover, most damage estimation methods disregard the effects of consecutive<br />earthquakes. Recent earthquakes have demonstrated that the aftershocks can cause<br />major damage to mainshock-damaged structures. After a strong seismic event, it<br />should be determined if a mainshock-damaged building is safe for reoccupation in<br />the event of aftershocks. This study examined the effects of both the main shock and<br />aftershocks on the damage index of reinforced concrete (RC) structures. Records<br />from 19 mainshocks that occurred in the Japan seismic region with moment<br />magnitudes of greater than 4 were examined. More than 100 acceleration time<br />series from these events (mainshock + aftershock events) were applied to evaluate<br />the damage index. Seismic damage analysis was performed on a series of RC<br />columns and RC frames. The natural period of these structures varied from 0.1 to 2.5<br />s. The damage index introduced by Park and Ang was employed to estimate the<br />structural damage. Acceleration time series were applied to the structures in two<br />steps. First, only mainshocks were applied to the structures and the damage index<br />was obtained. Next, both the mainshock and aftershocks were applied to the<br />structures and structures damaged by a mainshock were analyzed under periodic<br />aftershock events. The results showed that the increase in structural period and the<br />PGA of the aftershocks amplified the damage index under the effects of the<br />aftershocks. A modification to Park-Ang damage index is proposed using a dimensionless<br />term to accommodate the effect of aftershocks.https://www.jsee.ir/article_243311_eeb6523b0498555761717a55e6041609.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166921420191101Initial Solution for Designing a Soft Substructure in a Mass Isolation System with Consideration of Stability Constraints374824331010.48303/jsee.2019.243310ENMohammadBoujaryInternational Institute of Earthquake Engineering and Seismology (IIEES)MansourZiyaeifarInternational Institute of Earthquake Engineering and Seismology (IIEES)Journal Article20200120The new techniques in seismic design of structures are usually attributed to high<br />damping ratios. Mass isolation of structures is one of the new techniques in seismic<br />design of structures that focuses on the mass of the structure as the main target for<br />seismic isolation and reducing earthquake effects on buildings. Mass Isolation<br />System (MIS) consists of two stiff and soft substructures connected by a viscous<br />damper. The mass subsystem comprises the main mass of the structure, which is<br />attached to a frame with a low stiffness by a separation mechanism at the height of<br />the structure including viscous dampers to a stiffness subsystem consisting of a<br />moment or braced frame system with great stiffness. In this paper, the aim is to<br />present a simple preliminary design method based on the normalized pushover<br />curve. The most important problems for increasing the period of the soft structure<br />are deformation and structural stability. This paper presents a preliminary design<br />solution for a soft substructure of the Mass Isolation System (MIS) with consideration<br />of stability constraints. To this end, the paper presents mathematical<br />relationships to calculate the period of the structure followed by proposing a simple<br />solution for the design of the soft substructure.https://www.jsee.ir/article_243310_e2aaeff5f82d78bf62c3e7ee8b297ec1.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166921420191101Parallelization of 3D Pseudo-Bending Algorithm for Seismic Ray Tracing495624330910.48303/jsee.2019.243309ENMadinehBanihashem KalibarEarthquake Research Center, Ferdowsi University of MashhadHosseinSadeghiDepartment of Geology, Faculty of Science, Ferdowsi University of MashhadSayyed KeivanHosseiniEarthquake Research Center, Ferdowsi University of MashhadJournal Article20190416Bending ray tracing is a technique for finding the shortest travel path from a fixed source to a fixed receiver. Ray tracing is a time-consuming computing technique in applications such as tomography, which involves a large number of source-receiver pairs. In this regard, parallel programming makes it possible to reduce the running time of a serial program significantly by breaking it into a discrete series and solve it by different processing units simultaneously. Along with the rapid development of parallel computing technologies in both hardware architecture and system software, parallel computing is growing rapidly in a broad range of scientific computing applications. In this paper, the parallelization of pseudo-bending ray tracing algorithm is presented using both task and data parallelization strategies. In the task parallelization, the bending calculation of each path section is distributed to different processors, while in the data parallelization, due to the independent calculation for each pair of source-receiver, the data parts are distributed to different processors. The performance results of the parallelizations of the pseudo-bending algorithm for ray tracing in a 3D velocity model are shown using OpenMP, which is an application programming interface for shared memory multiprocessing programming. The advantage of OpenMP programming model is its simplicity to parallelize an existing serial code. This is especially useful now that multi-core CPUs are common. The results show the effectiveness and efficiency of the approach. A significant speedup in the ray tracing implementation is achieved. This reduction in computation time allows more rays to be traced, which directly affects the accuracy of tomography results. Sufficient ray coverage is needed to obtain tomography images with perfect resolution.https://www.jsee.ir/article_243309_7adc277687d79d5cc80465c5f389ae78.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166921420191101Interaction of Underground Tunnel and Existing Shallow Foundations Affected by Normal Faults576224331410.48303/jsee.2019.243314ENSadeghGhavamiSchool of Civil Engineering, Iran University of Science and TechnologyAlirezaSaeedi AzizkandiSchool of Civil Engineering, Iran University of Science and TechnologyMohammad HassanBaziarSchool of Civil Engineering, Iran University of Science and Technology0000-0003-1236-3987MehrdadRajabiDepartment of Civil Engineering, Islamic Azad University, South Tehran BranchJournal Article20200203In major earthquakes, permanent ground deformations due to the fault movements<br />cause serious damage to the foundations and structures. Although many of<br />structural seismic design codes have recommended avoiding the construction of<br />structures in the adjacent to active faults, it is not always a viable option. For<br />example, the lifeline facilities such as gas tunnels, water supply tunnels and<br />transportation tunnels, due to their extensive length, cannot often avoid crossing<br />active faults. Therefore, it is necessary to evaluate the interaction mechanism<br />between structures and fault rupture for effective design to reduce the hazards<br />associated with surface faulting. This study investigates the interactions of<br />underground tunnel and existing shallow foundation affected by normal fault<br />using the finite element method. The results show that the existence of a tunnel<br />changes the fault rupture path and in some cases can increase the foundation<br />rotation. It causes the occurrence of severe level of damage to the structure and<br />increases fear about its instability.https://www.jsee.ir/article_243314_3d990cd11ee0cd6f94c311955e2a49c9.pdf