International Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166921320190801Statistical Analysis of the Inter-Event Time, Distance, and Migrating Trend Distribution of Successive Large Earthquakes in Iran11224170510.48303/jsee.2019.241705ENSeyed Naser HashemiSchool of Earth Sciences, Damghan University, DamghanJournal Article20210118In this study, the waiting time, spatial distance, and migrating trend pattern of<br />successive large earthquakes in Iran have been investigated. In order to carry out<br />this work, the earthquake data of Iran with M >= 4.5 (1976-2018) have been<br />obtained from the USGS catalog. Then, the statistical distribution of the Interevent<br />time, migrating distance, and directional trend of migration of successive<br />events were studied using different lower magnitude thresholds. The statistical and<br />probability distributions of inter-event times of earthquakes were assessed and<br />modelled by different distribution models. Furthermore, the directional analysis<br />of migrating trends, as well as the spatial distances of successive events with<br />different lower magnitude, was carried out. It is observed that the inter-event time<br />distribution of earthquakes can be quite well fitted by the Gamma distribution<br />model. The results obtained also indicate a decreasing trend in spatial distance<br />distribution and a meaningful correlation between the directional pattern of the<br />migrating trends of successive events and the dominant trends of the active faults of<br />the region. The results of this study can be considered as an effective step to better<br />understanding the temporal-spatial pattern of seismicity in Iran and also as an<br />attempt to achieve earthquake prediction in this country, in a regional scale.http://www.jsee.ir/article_241705_8fd2e6e8e1745c2fbd689e04d3224c5a.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166921320190801An Experimental Study of Insufficient Free Board Effect on Fixed-Roof Cylindrical Tank Seismic Loads133024170610.48303/jsee.2019.241706ENMojtaba MoosapoorInternational Institute of Earthquake Engineering and SeismologyMohammad Mehdi YousefiBabol Noshirvani University of Technology (BUT)Mohammad Ali GoudarziInternational Institute of Earthquake Engineering and SeismologyJournal Article20190730Cylindrical tanks are fundamental structures used for the storage of liquids.<br />Sloshing caused by earthquakes in tanks without enough freeboard leads to a<br />liquid impact on the roof of tanks. This study aims to explore the base shear<br />variation due to insufficient freeboard using experimental and numerical methods.<br />The experimental tests are performed using a cylindrical liquid tank excited by<br />various harmonic loads. The impact of some parameters such as the water height to<br />tank radius ratio and freeboard on base shear force are investigated by conducting<br />90 tests. Impulsive and convective masses for simplified mass-spring are modified<br />in numerical models so that experimental and numerical base shear results<br />are consistent. Finally, a simple analytical solution to estimate the reduction of<br />convective mass due to insufficient freeboard is suggested and validated using<br />experimental results.http://www.jsee.ir/article_241706_8cb38d9b808db26d950f8f3cf971c371.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166921320190801Friction-Slip Connections for Moment Frames with Continuous Beams314824170710.48303/jsee.2019.241707ENFereshteh SeifanUniversity of Tehran, TehranSeyed Rasoul MirGhaderiUniversity of Tehran, TehranMehdi GhassemiehUniversity of Tehran, TehranJournal Article20210118This paper presents an assessment on a friction-slip connection for moment frames<br />with continuous beams based on the current detail. It also proposes a new configuration<br />for rigid connections in moment frames with continuous beams, which<br />can be developed as a friction-slip connection. In conventional moment frames,<br />beams are placed between two adjacent columns and connected to the column<br />flanges faces. However, in moment frames with continuous beams, two beams are<br />continuously passed next to the column. In the existing practice for connections in<br />these frames, two vertical connection plates placed on column flanges, and the<br />beams are connecting to these plates via their wings. In the mentioned detail, it was<br />assumed that the load transfers with in-plane action between connection plates<br />and column; therefore, the design force is pure shear, and based on the design<br />procedure, it should have been able to be developed for a friction-slip connection.<br />However, the results showed that the out-of-plane action of RPLs could be significant;<br />although this action provides extra capacity in moment connections, it<br />is not desirable in friction connections due to changes in the developed forces<br />in pretension bolts. Based on this action, a locking occurs, which changes the<br />performance of the connection considerably. As an alternative to this detail, a new<br />configuration is proposed in this paper, which can also be used as a friction-slip <br />connection and provides a friction connection in moment frames with continuous<br />beams. In new detail, by eliminating the effect of connection plate thickness, the<br />friction joint works as expected. Thus, instead of the plastic behavior of structural<br />elements, these friction joints can be used as an energy-dissipating system.http://www.jsee.ir/article_241707_4165ebfdf706cbbbafe869278ba377ef.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166921320190801Design of Mass Isolated Structures with Consideration of Stability Constraints496324170810.48303/jsee.2019.241708ENMohammad BoujaryInternational Institute of Earthquake Engineering and Seismology (IIEES), Tehran, IranMansour ZiyaeifarInternational Institute of Earthquake Engineering and Seismology (IIEES), Tehran, IranJournal Article20200120Vertical mass isolation is one of the new techniques in the seismic design of<br />structures that consists of two stiff and soft substructures connected by viscous dampers.<br />Adding to the flexibility and energy dissipation potential of the system is the main<br />feature of some new approaches in the seismic design of structures. Extra flexibility<br />helps to reduce earthquake-induced forces and accelerations in the building and<br />provides higher energy dissipation potential for the system (by creating large<br />relative deformations in the structure). Mass subsystem possesses low lateral<br />stiffness but carries the major part of the mass system. Stiffness subsystem, however,<br />controls the deformation of the mass subsystem and attributes with much higher<br />stiffness. In this paper, the aim is to find the limitation of the stability of a<br />soft structure and to obtain the maximum period available for a soft structure.<br />According to the studies, the most important obstruction in increasing the period<br />of the soft structure, assuming control of its deformation by connecting to the<br />stiff substructure, is to maintain the stability of the structure. In this paper, first, a<br />relationship has been presented to calculate the period of the structure in terms of<br />the stability factor that estimates the period of structure with good agreement by<br />analytical results. This paper deals with presenting a procedure for designing the<br />Mass Isolation System (MIS) with consideration of stability constraints. To this end,<br />the paper presents mathematical solutions to calculate the period of the structure<br />followed by proposing a design procedure of the soft substructure.http://www.jsee.ir/article_241708_28feb50fb53d5a1f6393681ddb029cdf.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166921320190801Detection of Long-Range Correlations and Trends Between Earthquakes in California657524170910.48303/jsee.2019.241709ENYasaman MalekiAlzahra UniversityMostafa AllamehzadehInternational Institute of Earthquake Engineering and SeismologyJournal Article20181215In this paper, we investigate the long-range correlations and trends between<br />consecutive earthquakes by means of the scaling parameter so-called locally Hurst<br />parameter, H(t), and examine its variations in time, to find a specific pattern that<br />exists between Earthquakes. The long-range correlations are usaully detected<br />by calculating a constant Hurst parameter. However, the multi-fractal structure of<br />earthquakes caused that more than one scaling exponent is needed to account<br />for the scaling properties of such processes. Thus, in this paper, we consider the<br />time-dependent Hurst exponent to realize scale variations in trend and correlations<br />between consecutive seismic activities, for all times. We apply the Hilbert-Huang<br />transform to estimate H(t) for the time series extracted from seismic activities<br />occurred in California during 12 years, from 2/24/2007 to 9/29/2017. The superiority<br />of the method is discovering some specific hidden patterns that exist between<br />consecutive earthquakes, by studying the trend and variations of H(t). Estimationg<br />H(t) only as a measure of dependency, may lead to misleading results, but using this<br />method, the trend and variations of the parameter is studying to discover hidden<br />dependencies between consecutive earthquakes. Recognizing such dependency<br />patterns can help us in prediction of future main shocks.http://www.jsee.ir/article_241709_4f9810e968789cc379d7b862c8d36934.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166921320190801Seismic Response Evaluation of Kashan Historical Bazaar Structure Including Soil-Structure Interaction779324171010.48303/jsee.2019.241710ENAmirhossein LaziziCivil Engineering Department, The University of Kashan, KashanHossein TahghighiCivil Engineering Department, The University of Kashan, KashanJournal Article20210118Historical heritage structures are especially vulnerable to earthquakes because<br />they were designed only for gravity loads without any consideration of lateral<br />loads. For this reason, the preservation and maintenance of these structures are of<br />great cultural, economic, and social importance. The present study investigates the<br />seismic vulnerability of a historical structure called Kashan Bazaar, located in<br />Kashan (central Iran), dating back to the 17th century. The detailed 3D geometrical<br />model of this structure was drawn using SolidWorks software. Finite element<br />numerical method was used to evaluate the response of Bazaar structure using<br />macro-modeling approach. Static, modal, and nonlinear static (pushover) analyses<br />were carried out using two cases, with soil-structure interaction (SSI) and without<br />SSI (fixed-base). According to the results, considering the SSI has a significant<br />influence on the mode shapes, vibration frequencies, and the structural responses.<br />The structure of Bazaar can withstand gravity loads as well as DBE demands<br />in fixed-base model. However, the results of the SSI analyses show the structure<br />weakness against lateral loads.http://www.jsee.ir/article_241710_cd8bad5da8208a0fbce894568aa2c0c0.pdf