International Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166919420171101Source Parameterization of Finite Faults in Earthquake Ground Motion Simulation261271240769ENAmenehHoushmandvikiInternational Institute of Earthquake Engineering and
Seismology (IIEES), TehranAnooshiravanAnsariInternational Institute of Earthquake Engineering and
Seismology (IIEES), TehranJournal Article20171218The effect of interpolation function for describing spatial variations of slip on the fault surface is investigated using finite fault simulation. In analogy with h-p notion in finite element method, the effect of increasing the order of interpolation function and decreasing the size of elements is studied here. In this regard, the fault surface is discretized using different elements, namely, constant discontinuous elements with various sizes, and first order contentious elements with different sizes. In order of parameterization, a bilinear interpolation technique is introduced to represent variation of source parameters within the subfault area. To provide an objective basis for comparison, the September 28, 2004 Parkfield earthquake Mw 6.1 is considered and time-frequency, envelope-phase goodness-of-fit criteria is calculated to compare synthetic and observed waveforms quantitatively in time and frequency domains. It was revealed that by increasing the order of interpolation function, the overall consistency of observed and synthetic waveforms will increase, while the expense of computational analyses will also increase accordingly.https://www.jsee.ir/article_240769_4841ec3ac73a45186d4014b3539cb083.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166919420171101Dynamic Properties of Firoozkooh Sand-Silt Mixtures273284240770ENAliShafieeCalifornia State Polytechnic University, PomonaRouzbehDabiriTabriz Branch, Islamic Azad University, TabrizFaradjollahAskariInternational Institute of Earthquake Engineering and Seismology (IIEES), TehranJournal Article20160610A series of undrained resonant column, monotonic and cyclic triaxial tests was performed to investigate the effects of non-plastic fines on the dynamic properties of Firoozkooh sand. Specimens of sand-silt mixtures were prepared at different densities, and tested under various confining pressures. Test results revealed that shear modulus decreases with fines, and increases with relative density and confining pressure. Normalized shear modulus is not affected by fines, relative density and confining pressure, while damping ratio is affected by fines and confining pressure. Finally, field cyclic resistance ratios versus normalized shear wave velocity values are developed on the basis of cyclic triaxial and resonant column tests.https://www.jsee.ir/article_240770_9e25d9cc32a4f87c6b9f484bc877a229.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166919420171101Equivalent Diagonal Strut Method for Masonry Walls in Pinned Connection and Multi-Bay Steel Frames299311240772ENSayed MohamadMotovali EmamiInternational Institute of Earthquake Engineering and Seismology (IIEES)0000-0002-7397-1639MajidMohammadiInternational Institute of Earthquake Engineering and Seismology (IIEES)Paulo B.LourençoUniversity of MinhoJournal Article20170709Equivalent compression strut is one of the most prevalent approaches recommended in seismic codes to simulate infill panels in the frames. The mechanical parameters of infilled frames, such as strength and stiffness, are controlled by material properties, thickness and width of equivalent strut. The strut width depends on the contact length between the infill and the frame. Previous studies have shown that the connection rigidity of the surrounding frame affects the contact length and consequently the response of infilled frame. Parametric finite element analyses have been carried out to investigate the influence of frame connection rigidity on the behavior of infill walls using ABAQUS environment. The finite elementmodels were verified based on the results of experimental data. It is shown that the stiffness and strength of infill panel in pinned connection steel frame are 0.9 and 0.8 times of those in rigid connection frame, respectively. The results of parametric finite element analyses were validated using equivalent strut method. Moreover, it is shown that the equivalent diagonal struts in multi-bay frame have the same properties of strut in one-bay frames for both rigid and pinned connections ones.https://www.jsee.ir/article_240772_a3b582d0b87f863b39d084dd851a7a89.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166919420171101Seismic Assessment of Trapezoidal-Shaped Hills Induced by Strong Ground Motion Records285298240771ENMasoudAmelsakhiQom University of TechnologyAbdollahSohrabi-BidarUniversity of TehranArashShareghiUrmia UniversityJournal Article20171010This study aims to rigorously examine the influences of the vertically propagating recorded strong ground motions on the trapezoidal-shaped hills in different sizes and shape ratios. In order to generalize the results of the study, one-dimensional as well as two-dimensional analyses are conducted. Then, intended results are represented in dimensionless form as a result of which amplification ratio patterns are extracted and compared with each other in terms of displacement, velocity, and acceleration. Similarly, corresponding response spectra ratios are derived on significant points on hill-crest, hill-side, and beside of that, and juxtaposed in diagrams. Results of the assessment are put together with that of recent studies and predictions of the reliable codes. An adequate agreement between maximum values of amplification ratios obtained in time-domain analyses and spectral analyses makes us hopeful to think of connecting time-domain parameters with spectra-related ones to propose an accurate equation, which considers more effective variations regarding the topographic seismic effects and gives most reliable prediction. However, here, an equation has already been suggested to draw amplification ratio patterns on different points of the hill for a limited hillshape, dimension, media characterization and constitutive model. Comparing the estimations of the amplification ratio patterns using different methods proves that, considering potent parameters related to the time-domain and frequency-domain, the proposed equation is more efficient than the other codes.https://www.jsee.ir/article_240771_d4374e17ce105114db5c4995905c5c5d.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166919420171101The Effects of Soil-Structure Interaction on Seismic Response of Steel Moment Resisting Frames313325240773ENSahandJabini AsliGraduate University of Advanced Technology, KermanHamedSaffariShahid Bahonar University, Kerman0000-0003-3866-1595Mohammad JavadZahediShahid Bahonar University of KermanJournal Article20170720The prediction of the seismic behavior of structures during earthquake has always been an important concern for earthquake and structural engineers. In addition to earthquakes, the behavior of soil and its effects on seismic responses of structure, also known as Soil-Structure Interaction (SSI), make this problem more complicated. For this purpose, today, many investigations are focusing on soil role in seismic behavior of structures. In this study, the seismic behavior of steel structures with various heights under the SSI effect have been studied. For this purpose, three steel structures including 9, 15 and 20 story frames were modeled using Opensees. Besides, their seismic behaviors under different base conditions including fixed base and on three different types of soil (B, C and D) under 11 bedrock earthquakes were also investigated using the direct method. The responses in two terms including story shear and story drift were also investigated.https://www.jsee.ir/article_240773_67fdb7de4ec86bcff50951880300f75b.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166919420171101Seismic Performance of Tall Buildings with Impact Damper under Near and Far-Field Earthquakes327336240774ENSeyed MehdiZahraiUniversity of Tehran0000-0003-2759-2424AlirezaHeisamiKhuzestan University, AhwazJournal Article20170827Impact dampers are considered among passive control devices. Experimental and analytical research studies have shown that this group of nonlinear dampers has a better performance for reducing structural vibrations as compared to linear vibrating neutralizers. Tall building is a structure that is different from other buildings in design aspects, construction, and operation due to its height. Medium height and tall models are used in the present paper in order to compare the performance of impact dampers in tall buildings. In this study, seismic performance of tall buildings with impact dampers is evaluated by using SAP2000 software. The condition of tall buildings with impact dampers is subsequently introduced. In order to achieve more desirable results for tall buildings subjected to seismic vibration, the earthquake records applied to multi degree of freedom systems are selected from both near and far-field seismic events. This study aims to represent how the impact damper operates in tall buildings and to determine the best location for its installation in order to reduce the response of vibrating system. Using nonlinear time history analysis, structural elements have been investigated based on AISC360-10 regulation in the design process. Among the results obtained in this research, reduction in the response of multi-degree-of-freedom systems in vibration condition using impact damper placed on the top floor can be mentioned. Moreover, it was observed that the more the frame height and its number of spans, the better the effect of placing impact damper in a story close to the roof as compared to placing itin the middle stories, which is due to the combination of vibration modes.https://www.jsee.ir/article_240774_87c4de00bb43761cd424c2f690410654.pdf