International Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166917420151101Idealized Bilinear Moment-Curvature Curves of Slender Rectangular RC Wall Sections223231240721ENP.SunithaIndian Institute of Technology MadrasC.V.R.MurtyIndian Institute of Technology MadrasRupenGoswamiIndian Institute of Technology MadrasJournal Article20161226Methods are proposed to develop idealized moment-curvature response curves of slender rectangular RC wall sections with uniformly distributed longitudinal reinforcement, using limit states, namely, cracking of concrete in tension, tensile yielding of reinforcement layers, and compression failure of concrete. It is recommended that tensile yielding of an inner layer of reinforcement is considered to develop idealized moment-curvature response curve of RC wall sections in the absence of compressive axial load, as against tensile yielding of extreme layer of reinforcement in the presence of compressive axial loads. Distance of the critical inner layer of reinforcement from highly compressed edge depends on percentage of longitudinal reinforcement in the section; the distance varies from 0.5D to 0.98D with an increase in percentage of longitudinal reinforcement, where D is the length of the wall, but does not depend on plan aspect ratio. Furthermore, axial-flexure interaction envelope can also be developed from the idealized moment-curvature response curves.https://www.jsee.ir/article_240721_8c88b34cd6ffd2d702864871eafd7091.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166917420151101Floor Response Modification Factors for Nonstructural Components due to Near-Field Pulse-Like Earthquakes249263240723ENLayaAbbasiInternational Institute of Earthquake Engineering and Seismology (IIEES)MohsenGhafory-AshtianyIIEESJournal Article20150803Floor response modification factor (R) under near-field strong ground motions (SGMs) with directivity pulses are proposed in this paper. The R factor is defined as the floor response spectrum (FRS) for linear elastic primary structures normalized by the FRS for an inelastic primary structure. The terms ‘elastic’ and ‘inelastic’ refer to the behavior of the supporting structure while only elastic nonstructural components (NSCs) are used in this study.Considering the lack of comprehensive study on the behavior of NSCs under near-field SGMs with directivity pulses, this study evaluates the dependence of the proposed response modification factor (R) under bunches of near-field records with wide ranges of directivity pulse periods. A statistical analysis of the peak response of NSCs supported on inelastic regular moment-resisting frame structures exposed to near-field pulse-like SGMs is presented. Peak component demands were quantified based on the FRS method with considering dynamic interaction effects. In This paper the main factors affecting the FRS caused by inelasticity in the primary structures represented by parameter R has been evaluated. The results show that FRS values at the initial modal periods of the supporting structure are reduced due to the inelastic action in the primary structures. Comparing the results with the same earthquake events without directivity pulses shows that the reduction factor in near-field pulse-like SGMs is considerably larger than R factor in far-field SGMs.https://www.jsee.ir/article_240723_27bd8c55601e2b2c1be0bf6e876c86e9.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166917420151101Fragility Curve Development for Assessing Midrise Steel Building with Buckling Resistant Braced System Having Vertical Irregularity293304240726ENHamzehShakibTarbiat Modares UniversityMehdiNodehTarbiat Modares UniversityFarshadHomaeiTarbiat Modares UniversityJournal Article20150822In this paper, the fragility curves have been developed for assessing vertically irregular midrise steel building with Buckling Resistant Braced (BRB) system. The effect of different vertical irregularities of mass, stiffness and the concurrent variation of stiffness and strength was investigated in the seismic response of a ten-story steel building. The fragility curves of both the regular and irregular structures were developed through the incremental dynamic analysis and the effects of vertical irregularities were evaluated in the seismic performance of the structure. Fragility curves show that among all the vertical irregularities, variation in the mass has little effect on the probability exceedance of demand from capacity. Meanwhile, the concurrent variation of stiffness and strength shows a significant increase in the probability exceedance of demand from capacity, especially through the nonlinear phase of structural behavior, through the collapse prevention to the global instability limit states.https://www.jsee.ir/article_240726_35315b827e53e568ecfe3d20a6577466.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166917420151101Time-Dependent Seismic Assessment of Typical Highway Bridges Subjected to Corrosion in Persian Gulf Zone265280240724ENAfshinKalantariIIEESMortezaAmooieIslamic Azad University - South Tehran BranchJournal Article20150526In high seismic regions, such as Persian Gulf zone in Iran, corrosion of reinforcement and concrete deterioration can affect the seismic capacity of the structures and increase the vulnerability to the future seismic events. Although corrosion of reinforcement has the potential to affect all types of reinforced concrete structures, the highway bridges are vulnerable to more damage because of deicing salts, water splash or even seawater during their life cycle. The long-term corrosion process of a deteriorated typical RC highway bridge in Iran is analyzed as a function of time by using nonlinear static and dynamic analyses for seven earthquake ground motion records at three levels of intensity (0.3g, 0.5g and 0.75g). Three combined effects of corrosion (the loss of the cross sectional area of the reinforcement bars, decrease of the capacity of corroded reinforcing bars, and stiffness degradation of concrete cover resulting from reinforcement corrosion) were used in the time-dependent nonlinear analyses for six different time steps (i.e., non-corroded (t: 0), 10, 20, 30, 40, and 50 years) after corrosion initiation time. The results show that removing the concrete cover on bottom of columns has a greater impact on the structural capacity of the RC bridge than decreasing the rebar mechanical parameters.https://www.jsee.ir/article_240724_99af4a11124187bff5dd4fcec4386113.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166917420151101Reliability Analysis of Liquefaction Utilizing Monte Carlo Simulation Based on Simplified Stress Method233248240722ENJalalKasebzadehShahid Beheshti UniversityAliNoorzadShahid Beheshti UniversityAhmad RezaMahboubiShahid Beheshti UniversityJournal Article20161231Liquefaction analysis is one of the most challenging issues in seismic geotechnical engineering. The unknown factors and pertinent uncertainties involved in the evaluation of liquefaction potential make the problem to be complicated. Liquefaction evaluation include deterministic and probabilistic methods. Deterministic methods are simple but they are not capable to consider the uncertainties. With regard to heterogeneous nature of the soil and probabilistic nature of earthquake loading, it seems that deterministic method is not sufficient for evaluation of liquefaction. Reliability methods are able to capture the uncertainties depending on variability of soil parameters and also to determine the factor of safety proportional to the acceptable risk. In recent years, reliability analysis of liquefaction has been done using approximated method. In the present research, reliability analysis of liquefaction triggering has been discussed using Monte Carlo simulation that is an accurate method. For this purpose, the parameters earthquake magnitude (Mw ), maximum horizontal acceleration (amax /g), total stress (sv ), effective stress (s'v ), fines content percent (FC), and SPT blow count (NSPT) are selected as stochastic parameters and the probability of liquefaction has been estimated. Application of the proposed method to the 233 well-documented case studies verify that deterministic method is not accurate enough to predict the liquefaction and reliability analysis should be used instead. Besides, the sensitivity tests indicate that the SPT blow count is the most influential parameter in liquefaction evaluation and large number of iterations is not required in Monte Carlo Simulation and the results converge after a specific number of iterations.https://www.jsee.ir/article_240722_d95c0a192f25f41ea3242442c84463a1.pdfInternational Institute of Earthquake Engineering and SeismologyJournal of Seismology and Earthquake Engineering1735-166917420151101Effect of Flange Width of Vertical Link Beam on Cyclic Behavior of Chevron Braced Steel Frames281292240725ENSeyed MehdiZahraiUniversity of Tehran, Tehran0000-0003-2759-2424AmirParsaUniversity of Tehran, TehranJournal Article20161226Among the passive dampers, using Vertical Link Beam (VLB) is one of the most effective and simplest methods, while not embedded in the floor they can be easily replaced after earthquakes. These dampers dissipate a major part of the input energy resulting in a minimized damage of the main structural components of system. This paper presents a numerical study on the impact of flange width of VLB on cyclic performance of chevron braced steel frames. Despite most previous research projects in which wide-flange I sections were considered for the VLB and the length of VLB was studied, here, the objective is to investigate the possibility of using narrower flange. Verification has been made on the basis of the experimental results from the IPE160 model. By changing the flange width, the cyclic behavior has been investigated. The results show that while the vertical link beam has sufficient lateral support, in spite of the flange width reduction, stable hysteretic cycles still form accompanied with considerable energy dissipation. Based on the hysteretic curves, using modification of the narrower flange section, the shear force at last cycle increased about 20.74% and 16.17% in IPE160 VLBs with a half and quarter flange width respectively, and the proportion of VLB in plastic energy dissipation increased from 78.9% to 90.4% in half flange VLB and from 74.2% to 90.9% in quarter flange VLB only by this simple modification, showing an increase in ductility of the system.https://www.jsee.ir/article_240725_1f1423bb12fdb47333c9e2e316f8aeb9.pdf