Strong ground motion record selection for the reliable prediction of the mean seismic collapse capacity of a structure group     

Mohsen Ghafory‐Ashtiany  Mehdi Mousavi  Alireza Azarbakht 《地震工程与结构动力学》2011,40(6):691-708

How to select a limited number of strong ground motion records (SGMRs) is an important challenge for the seismic collapse capacity assessment of structures. The collapse capacity is considered as the ground motion intensity measure corresponding to the drift‐related dynamic instability in the structural system. The goal of this paper is to select, from a general set of SGMRs, a small number of subsets such that each can be used for the reliable prediction of the mean collapse capacity of a particular group of structures, i.e. of single degree‐of‐freedom systems with a typical behaviour range. In order to achieve this goal, multivariate statistical analysis is first applied, to determine what degree of similarity exists between each selected small subset and the general set of SGMRs. Principal Component analysis is applied to identify the best way to group structures, resulting in a minimum number of SGMRs in a proposed subset. The structures were classified into six groups, and for each group a subset of eight SGMRs has been proposed. The methodology has been validated by analysing a first‐mode‐dominated three‐storey‐reinforced concrete structure by means of the proposed subsets, as well as the general set of SGMRs. The results of this analysis show that the mean seismic collapse capacity can be predicted by the proposed subsets with less dispersion than by the recently developed improved approach, which is based on scaling the response spectra of the records to match the conditional mean spectrum. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

A study of differentiation pattern and rare earth elements migration in geochemical and hydrogeochemical environments of Airekan and Cheshmeh Shotori areas (Central Iran)     

Mostafa Esmaeili-Vardanjani  Reza Shamsipour-Dehkordi  Alireza Eslami  Firouz Moosaei  Kaveh Pazand 《Environmental Earth Sciences》2013,68(3):719-732

The Airekan and Cheshmeh Shotori areas are located about 60 km northeast of Khour, in Isfahan province from Central Iran. Research on characteristics and rare earth elements (REE) pattern in hydrogeochemical environments of these areas suggests the same origin for the elements dissolved in groundwater in these areas. Investigation of migration pattern of REE in hydrogeochemical environments shows that the migration and transportation of REE has occurred through chloride complexes. REEs, leached by water/rock interaction from the Airekan granite, are transported by groundwater and then precipitated in the Cheshmeh Shotori area. Study of the Cheshmeh Shotori sediments shows the presence of a sequence of red oxidized and dark layers. Geochemical characteristics of these sediments reveal that their REE characteristics are mainly inherited from the Airekan granite. Changes in the REE pattern of these sediments with depth show that changes in oxidation and reduction process have not played a significant role in controlling their behavior. It is crucial to note that adsorption of REEs dissolved in water by hydrosilicate increases these elements in depth. The REE behavior shows water/rock interaction between the granitic rocks and groundwater as the main factor of solution, migration and precipitation of REEs in the Cheshmeh Shotori area.  相似文献   

Optimization of Flue Gas Composition to Maximize Base Gas Replacement During UGS Process     

Namdar  Hamed  Khodapanah  Elnaz  Tabatabaei-Nejad  Seyyed Alireza 《Natural Resources Research》2020,29(6):4175-4197

Natural Resources Research - Base gas replacement by a cheap gas is one of the approved methods to reduce the cost of investment in underground gas storage process. Maximizing the amount of...  相似文献   

Hydrodynamic Tidal Model of the Persian Gulf Based on Spatially Variable Bed Friction Coefficient     

Mostafa Sohrabi Athar  Alireza A. Ardalan  Roohollah Karimi 《Marine Geodesy》2019,42(1):25-45

The aim of this study is to develop a two-dimensional hydrodynamic tidal model for the Persian Gulf (PG2017) using 2D-MIKE21 software. The advantages of present study is accounting for the spatial variation of bed friction coefficient besides a precise bathymetry together with a 23-year of combined records of satellite altimetry data. We found that the bed friction coefficient has a significant effect on sea level changes in the region under our modeling consideration. Since the tidal behavior in the northern part of the Qeshm Island is significantly different from the other parts of the Persian Gulf, to present a more accurate hydrodynamic tidal model, the Gulf is divided into two regions where the bed friction coefficient is modeled separately for each region. The root mean square value of the differences between the amplitude of dominant constituents; M2, S2, K1, and O1 derived from the PG2017 model and that of 98 altimetry and coastal tide gauge stations are respectively equal to 1.6, 1.9, 2.8, and 1.3?cm. Moreover, comparing the PG2017 model efficiency with the FES2014, OSU12, EOT11a, DTU10, and Admiralty models shows that the PG2017 model has an improvement of 22.1%, 47.2%, 43.2%, 44.2%, and 57.6% in terms of relative error, respectively.  相似文献   

Long-term coupled behaviour of cemented paste backfill in load cell experiments     

Alireza Ghirian 《Geomechanics and Geoengineering》2016,11(4):237-251

A pressure cell apparatus has been developed in this research work to study the long-term hydro-mechanical behaviour of cemented paste backfill (CPB) cured under applied stress. The samples are cured for 7, 28, 90 and 150 days and the evolution of their mechanical, hydraulic, physical and microstructural properties is studied. Also, the suction, temperature and electrical conductivity are monitored for a period of 150 days of curing. The testing and monitoring programmes are conducted in undrained conditions, with and without pressure application. The obtained results show that the curing stress affects the hydro-mechanical behaviour of CPB for up to 28 days. Within this curing period, the CPB exhibits enhanced hydro-mechanical performance. However, application of sustained excessive curing stress onto the CPB samples induces the propagation of microcracks in the backfill structure, thus causing lower mechanical strength and higher fluid permeability at the more advanced ages. Furthermore, the mineralogical and chemical compositions of the tailings (e.g., sulfidic tailings) can significantly alter the mechanical strength properties (uniaxial compressive strength and elastic modulus) and the permeability of the CPB. The evolution of coupled factors and characteristics of the CPB at an early age control and influence its long-term behaviour and performance.  相似文献   

Heavy metals adsorption by nanozeolites: effect of sodium hexametaphosphate     

Mehdi Irannajad  Hossein Kamran Haghighi  Alireza Mohammadjafari 《Environmental Earth Sciences》2016,75(13):1058

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A harmonic approach to global ocean tide analysis based on TOPEX/Poseidon satellite     

Alireza Azmoudeh Ardalan  Hassan Hashemi-Farahani 《Marine Geophysical Researches》2007,28(3):235-255

The constant and harmonic parts of the global ocean tide are modeled by up to nine major tidal constituents, namely, S2, M2, N2, K1, P1, O1, Mf, Mm, and Ssa. Our computations start with the Fourier sine and cosine series expansion for the tidal constituents, including the constant Mean Sea Level (MSL). Although the frequencies of the tidal constituents are considered known, the coefficients of the sine and cosine functions are assumed to be unknown. Subsequently, the coefficients of the sine and cosine functions, as well as the constant part of the Fourier expansion, were expanded into spherical harmonics up to degree and order n, where n corresponds to the number of linearly independent spherical harmonic base functions needed to model the tidal constituents, determined via independent columns of the Gram matrix. The unknown coefficients of the spherical harmonic expansions are computed using sea level observations within cycles #1–#350 of the TOPEX/Poseidon satellite altimetry over 11 years of its mission. A set of orthonormal base functions was generated for the marine areas covered by TOPEX/Poseidon observations from the spherical harmonics using a Gram-Schmidt orthogonalization process. These were used for modeling the dominant tidal constituents. The computed models based on orthonormal base functions for the nine tidal constituents and the constant part of the Fourier expansion, were tested numerically for their validity and accuracy, proving centimeter accuracy.  相似文献   

Copper isotope fractionation in the Meiduk porphyry copper deposit,Northwest of Kerman Cenozoic magmatic arc,Iran          下载免费PDF全文

Sina Asadi  Ryan Mathur  Farid Moore  Alireza Zarasvandi 《地学学报》2015,27(1):36-41

The Meiduk deposit possesses three different Cu reservoirs each with a unique Cu isotope signature. δ⁶⁵Cu for the leached cap minerals ranges from ?2.5 to +0.49‰ to ?0.45 to +0.3‰ for hypogene minerals and from +1.3 to +4.4‰ for supergene enrichment minerals. Oxidation of hypogene sulphides and effective trapping of copper (from solutions derived from the leached cap) in the supergene enrichment zone caused this relationship. A systematic pattern of low Cu isotope values close to the surface and higher isotope values with depth reveals a palaeo‐fluid pathway in the northwest–southeast direction over the deposit. Thus, the copper isotope data from leached cap and enrichment minerals can be used to monitor copper migration during supergene weathering at the Meiduk deposit.  相似文献   

Monitoring and projection of climate change impact on 24-h probable maximum precipitation in the Southeast of Caspian Sea     

Afzali-Gorouh  Zahra  Faridhosseini  Alireza  Bakhtiari  Bahram  Mosaedi  Abolfazl  Salehnia  Nasrin 《Natural Hazards》2022,114(1):77-99

Natural Hazards - Due to the impacts of climate change on probable maximum precipitation (PMP) and its importance in designing hydraulic structures, PMP estimation is crucial. In this study, the...  相似文献   

Compounding effects of human activities and climatic changes on surface water availability in Iran     

Ashraf  Samaneh  AghaKouchak  Amir  Nazemi  Ali  Mirchi  Ali  Sadegh  Mojtaba  Moftakhari  Hamed R.  Hassanzadeh  Elmira  Miao  Chi-Yuan  Madani  Kaveh  Mousavi Baygi  Mohammad  Anjileli  Hassan  Arab  Davood Reza  Norouzi  Hamid  Mazdiyasni  Omid  Azarderakhsh  Marzi  Alborzi  Aneseh  Tourian  Mohammad J.  Mehran  Ali  Farahmand  Alireza  Mallakpour  Iman 《Climatic change》2019,152(3-4):379-391

Climatic Change - By combining long-term ground-based data on water withdrawal with climate model projections, this study quantifies the compounding effects of human activities and climate change...  相似文献