http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Abdolreza S. Moghadam (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
-
Seismic response of torsional structures considering the possibility of diaphragm flexibility
Hamed Eivani,Abdolreza S. Moghadam 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.77 No.4
Fully rigid floor diaphragm is one of the main assumptions that are widely used in common practices due to its simple application. However, determining the exact degree of diaphragms flexibility cannot be easily accomplished without finite element modeling, which is an expensive and time-consuming procedure. Therefore, it is always possible that apparently rigid diaphragms, based on prescriptive limitations of seismic codes, experience some degrees of flexibility during the earthquakes. Since diaphragm flexibility has more uncertainties in asymmetric-plan structures, this study focuses on errors resulting from probable floor diaphragm flexibility of torsionally restrained structures. The analytical models used in this study were single-story buildings with asymmetric plan and RC shear walls. Although floor system is not considered explicitly, a wide range of considered diaphragm flexibility, from fully rigid to quite flexible, allows the results to be generalizable to a lot of lateral load resisting systems as well as floor systems. It has been shown that in addition to previously known effects of diaphragm flexibility, presence of orthogonal side elements during design procedure with rigid diaphragm assumption and rapid reduction in their absorbed forces can also be an important source to increase errors due to flexibility. Accordingly, from the obtained results the authors suggest designers to consider the possibility of diaphragm flexibility and its adverse effects, especially in torsionally restrained systems in their common designs.
-
Response of self-centering braced frame to near-field pulse-like ground motions
Navid Rahgozar,Abdolreza S. Moghadam,Armin Aziminejad 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.62 No.4
A low damage self-centering braced frame equipped with post-tensioning strands is capable of directing damage to replaceable butterfly-shaped fuses. This paper investigates the seismic performance of rocking braced frame under near-field pulse-like ground motions compared to far-field records. A non-linear time history analysis is performed for twelve self-centering archetypes. A sensitivity analysis is carried out to examine the influences of ground motion types and modeling parameters. Findings represent the proper efficiency of the self-centering system under both far-field and near-field pulse-like ground motions.
-
Maryam Samimifar,Ali Massumi,Abdolreza S. Moghadam 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.70 No.3
Hysteretic energy is defined as energy dissipated through inelastic deformations during a ground motion by the system. It includes frequency content and duration of ground motion as two remarkable parameters, while these characteristics are not seen in displacement spectrum. Since maximum displacement individually cannot be the appropriate criterion for damage assessment, hysteretic energy has been evaluated in this research as a more comprehensive seismic demand parameter. An innovative methodology has been proposed to establish a new equivalent linear model to estimate hysteretic energy spectrum for bilinear SDOF models under two different sets of earthquake excitations. Error minimization has been defined in the space of equivalent linearization concept, which resulted in equivalent damping and equivalent period as representative parameters of the linear model. Nonlinear regression analysis was carried out for predicting these equivalent parameter as a function of ductility. The results also indicate differences between seismic demand characteristics of far-field and near-field ground motions, which are not identified by most of previous equations presented for predicting seismic energy. The main advantage of the proposed model is its independency on parameters related to earthquake and response characteristics, which has led to more efficiency as well as simplicity. The capability of providing a practical energy based seismic performance evaluation is another outstanding feature of the proposed model.
-
Enhanced Accuracy of a Fuzzy Logic Model for Rapid Seismic Damage Prediction of RC Buildings
Omid Zaribafian,Towhid Pourrostam,Mehdey Fazilati,Abdolreza S. Moghadam,Ali G. Pahlaviani 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.1
Rapid Visual Screening (RVS) is a method of assessing a building’s vulnerability to an earthquake. Although RVS accurately classifies the damage states of the studied buildings, the parameter values assigned by this method have intrinsic uncertainties that can highly reduce the accuracy of its predictions. Accordingly, using a fuzzy logic model is known to mitigate these uncertainties and offer a more reliable level of damage prediction. A recently-proposed Dual-Fitness Particle Swarm Optimization (DFPSO) algorithm is applied to fine-tune the hyperparameters of this model, named the FLM-DFPSO model. Furthermore, the 1994 Northridge earthquake data is used to benchmark the performance of the proposed model against a well-known model in the literature. The results suggest that the proposed model improves the performance criteria by 7.46% and 27% in the training and validation stages, respectively. The model also boosts the prediction accuracy by a rate of 53% in the validation step, confirming the FLM-DFPSO as a highly reliable model to learn and also generalize the relationship between its inputs and output to other cases when assessing seismic damage.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
