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single-degree-of-freedom-structures
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Clearance effects on dynamic behavior of a continuous mechanical system
, Article JVC/Journal of Vibration and Control ; Volume 21, Issue 13 , October , 2015 , Pages 2509-2519 ; 10775463 (ISSN) ; Momeni Massouleh, S. H ; Khorasani, R ; Sharif University of Technology
SAGE Publications Inc
2015
Abstract
An analytical modified method is presented to investigate the clearance effects on the dynamic behavior of cantilever beams. In this work, apart from clearance, all other nonlinearities are avoided to be considered during the analytical solution. The beam is idealized using an equivalent single-degree-of-freedom structure. A tri-linear stiffness system is also adopted to simulate the beam together with the clearance. Subsequently the analytical solution is derived for a cantilever beam structure with and without considering structural damping. The experimental method is employed to verify the results from the presented analytical solutions. It is noted that the results obtained by the...
Simplified Methods to Estimate the Response of Non-linear Soil-structure Interaction Systems
, M.Sc. Thesis Sharif University of Technology ; Ghannad, Mohammad Ali (Supervisor)
Abstract
Usually the structures are designed based on the fixed-base assumption; however thisassumption is not always correct and the bed flexibility should be considered. This effectwhich is called soil-structure interaction, change the response of structure on both elasticand inelastic behavior. In the regulations for the design of structures on flexible base,generally soil-structure system is replaced with an equivalent fixed base structure; in theway that the design force of soil-structure system with reasonable accuracy can beestimated by equivalent fixed-base structure. In some regulations, dynamic characteristicsof equivalent structure have been determined on elastic state and the results have...
Risk-based Approach to Account for Soil-Structure Interaction in Seismic Design of Building Structures
,
Ph.D. Dissertation
Sharif University of Technology
;
Ghannad, Mohammad Ali
(Supervisor)
;
Mahsuli, Mojtaba
(Supervisor)
Abstract
This paper proposes a novel probabilistic approach to account for soil-structure interaction (SSI) in the seismic design of building structures. In this approach, an SSI response modification factor, RSSI, is introduced to capture SSI effects on the seismic performance of structures. The proposed procedure quantifies RSSI such that the probability distribution of the collapse capacity of the structure designed to account for SSI concurs with that of the structure designed using the default fixed-base provisions. The proposed approach is employed for special steel moment frame buildings with surface foundation. A surrogate single degree of freedom (SDOF) system is developed in this study and...
Incorporation of strong motion duration in incremental-based seismic assessments
, Article Engineering Structures ; Volume 223, Issue 15 , November , 2020 ; Harati, M ; Darzi, A ; Estekanchi, H. E ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
This study proposes a new approach to incorporate motion duration in incremental dynamic assessments. In the proposed methodology, at each intensity level, a simulation-based approach which is verified with actual data is employed to determine the median duration and the median acceleration spectra of ground motions expected to occur at the site. Afterward, at each intensity level, artificial or spectrally matched motions are produced based on the median acceleration spectra and the median duration, indicating that different intensity levels are directly covered by the generated artificial or adjusted motions rather than just scaling up and down a set of recorded ground motions. In the...
On lateral response of structures containing a cylindrical liquid tank under the effect of fluid/structure resonances
, Article Journal of Sound and Vibration ; Volume 318, Issue 4-5 , 2008 , Pages 1154-1179 ; 0022460X (ISSN) ; Rahimzadeh Rofooei, F ; Sharif University of Technology
Academic Press
2008
Abstract
The lateral response of a single degree of freedom (SDOF) structural system containing a rigid circular cylindrical liquid tank, under harmonic and earthquake excitations is considered. The governing differential equations of motion for the combined system is derived considering the first 3 liquid sloshing modes (1,1), (0,1), and (2,1), under horizontal excitation. The system is considered nonlinear due to the convective term of liquid acceleration and the nonlinear surface boundary conditions, both caused by the inertial nonlinearity. The harmonic and seismic response of the system is investigated in the neighborhood of 1:1 and 1:2 internal resonances between the SDOF system and the first...
On the modal incremental dynamic analysis of reinforced concrete structures, using a trilinear idealization model
, Article Engineering Structures ; Volume 33, Issue 4 , 2011 , Pages 1117-1122 ; 01410296 (ISSN) ; Mofid, M ; Sharif University of Technology
Abstract
In order to estimate the seismic demands at the performance level, the inelastic behavior of concrete structures should be considered. Incremental dynamic analysis (IDA) based on a nonlinear response time history analysis (NL-RHA) is considered to be the most accurate method in seismic demand calculations. However, modal incremental dynamic analysis (MIDA), based on the equivalent single-degree-of-freedom (SDF) oscillator, is also often used in studying structural engineering performances. As the MIDA method has usually not been applied to reinforced concrete (RC) structures, in this study an attempt is made to investigate the performances of RC frames and to compare the results obtained...