• Title, Summary, Keyword: OpenSees

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Response modification factor of the frames braced with reduced yielding segment BRB

  • Fanaie, Nader;Dizaj, Ebrahim Afsar
    • Structural Engineering and Mechanics
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    • v.50 no.1
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    • pp.1-17
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    • 2014
  • In this paper, overstrength, ductility and response modification factors are calculated for frames braced with a different type of buckling restrained braces, called reduced yielding segment BRB (Buckling Restrained Brace) in which the length of its yielding part is reduced and placed in one end of the brace element in comparison with conventional BRBs. Forthermore, these factors are calculated for ordinary BRBF and the results are compared. In this regard incremental dynamic analysis (IDA) method is used for studying 17 records of the most known earthquakes happened in the world. To do that, the considered buildings have different stories and two bracing configurations: diagonal and inverted V chevron, the most ordinary configurations of BRBFs. Static pushover analysis, nonlinear incremental dynamic analysis and linear dynamic analysis have been performed using OpenSees software. Considering the results, it can be seen that, overstrength, ductility and response modification factors of this type of BRBF(Buckling Restrained Braced Frame) is greater than those of conventional types and it shows better seismic performance and also eliminates some of conventional BRBF's disadvantages such as low post-yield stiffness.

Structure-soil-structure interaction in a group of buildings using 3D nonlinear analyses

  • Sharifi, Behroozeh;Nouri, Gholamreza;Ghanbari, Ali
    • Earthquakes and Structures
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    • v.18 no.6
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    • pp.667-675
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    • 2020
  • The current study compares the effect of structure-soil-structure interaction (SSSI) on the dynamic responses of adjacent buildings and isolated structures including soil-structure interaction (SSI) with the responses of fixed-base structures. Structural responses such as the relative acceleration, displacement, drift and shear force were considered under earthquake ground motion excitation. For this purpose, 5-, 10- and 15-story structures with 2-bay moment resisting frames resting on shallow foundations were modeled as a group of buildings in soft soil media. Viscous lateral boundaries and interface elements were applied to the soil model to simulate semi-infinite soil media, frictional contact and probable slip under seismic excitation. The direct method was employed for fully nonlinear time-history dynamic analysis in OpenSees using 3D finite element soil-structure models with different building positions. The results showed that the responses of the grouped structures were strongly influenced by the adjacent structures. The responses were as much as 4 times greater for drift and 2.3 times greater for shear force than the responses of fixed-base models.

Damage Evaluation of Reinforced Concrete and Steel Frames under Critical Successive Scenarios

  • Amiri, Gholamreza Ghodrati;Rajabi, Elham
    • International journal of steel structures
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    • v.17 no.4
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    • pp.1497-1516
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    • 2017
  • This paper compares the vulnerability of initial shock-damage reinforced concrete (RC) with steel frames in successive scenarios, as an essential part of developing a framework to consider seismic sequence hazard into structural design. For this, two sets of regular RC and steel moment resisting frames with 3, 5, 7, 10, 12 and 15 stories, are designed and analyzed under two different databases with/without seismic sequences in OpenSees software.The damage states of the model frames were then measured by the Park and Ang's damage index. From the results of this investigation, it is observed that only considering the mainshock will underestimate the seismic risk in both sets of RC and steel frames. The results of damage evaluation also reveal that RC frames have better performance than steel frames in seismic sequence phenomena. Furthermore, steel frames damage is about 53% more than the damage caused by RC frames under critical successive earthquakes.

Multiscale modeling of reinforced/prestressed concrete thin-walled structures

  • Laskar, Arghadeep;Zhong, Jianxia;Mo, Y.L.;Hsu, Thomas T.C.
    • Interaction and multiscale mechanics
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    • v.2 no.1
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    • pp.69-89
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    • 2009
  • Reinforced and prestressed concrete (RC and PC) thin walls are crucial to the safety and serviceability of structures subjected to shear. The shear strengths of elements in walls depend strongly on the softening of concrete struts in the principal compression direction due to the principal tension in the perpendicular direction. The past three decades have seen a rapid development of knowledge in shear of reinforced concrete structures. Various rational models have been proposed that are based on the smeared-crack concept and can satisfy Navier's three principles of mechanics of materials (i.e., stress equilibrium, strain compatibility and constitutive laws). The Cyclic Softened Membrane Model (CSMM) is one such rational model developed at the University of Houston, which is being efficiently used to predict the behavior of RC/PC structures critical in shear. CSMM for RC has already been implemented into finite element framework of OpenSees (Fenves 2005) to come up with a finite element program called Simulation of Reinforced Concrete Structures (SRCS) (Zhong 2005, Mo et al. 2008). CSMM for PC is being currently implemented into SRCS to make the program applicable to reinforced as well as prestressed concrete. The generalized program is called Simulation of Concrete Structures (SCS). In this paper, the CSMM for RC/PC in material scale is first introduced. Basically, the constitutive relationships of the materials, including uniaxial constitutive relationship of concrete, uniaxial constitutive relationships of reinforcements embedded in concrete and constitutive relationship of concrete in shear, are determined by testing RC/PC full-scale panels in a Universal Panel Tester available at the University of Houston. The formulation in element scale is then derived, including equilibrium and compatibility equations, relationship between biaxial strains and uniaxial strains, material stiffness matrix and RC plane stress element. Finally the formulated results with RC/PC plane stress elements are implemented in structure scale into a finite element program based on the framework of OpenSees to predict the structural behavior of RC/PC thin-walled structures subjected to earthquake-type loading. The accuracy of the multiscale modeling technique is validated by comparing the simulated responses of RC shear walls subjected to reversed cyclic loading and shake table excitations with test data. The response of a post tensioned precast column under reversed cyclic loads has also been simulated to check the accuracy of SCS which is currently under development. This multiscale modeling technique greatly improves the simulation capability of RC thin-walled structures available to researchers and engineers.

A Case Study for SMRT Train Open Doors Control System (도시철도의 열차출입문제어에 관한 연구)

  • Won, Yu-Duck;Shim, Won-Sub
    • Proceedings of the KSR Conference
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    • pp.941-946
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    • 2006
  • It followed in system development and SMRT(Seoul Metropolitan Rapid Transit Co)System reached to an automatic train operation(ATO) and driverless operation(DLM) from the manual operation due to the train driver. The train like the general bus or the car vehicle was not serial riding in a car and the Parallel concept which the numerous passenger rides in a car simultaneously occur frequently the charge of the train driver unmanned bitterly from existing manual handling was a possibility of doing, train open door control(ODM) which bites also ATO, it handles it minimized. Like this ATO/DLM, the control system which bites being a Wayside to Train communication for immediacy, it is a system of the Vital concept the immediacy of the citizen Data evil the radio information transmission and the train of the interface which is accurate from unmanned operation and, will decipher, will accomplish it will guarantee. It respects the passenger accident prevention and an air question environment improvement from subway platform and phul leys the screen door of Platform(PSD) with the fire tube frost it refers and part it treats and to sleep it does, ODM which bites is accuracy and immediacy of altitude and when seeing from the viewpoint which demands the trust of altitude, ODM system the trust of car incest interface in the equipment construction which is safe and the comparative analysis back of the system analysis against the control which bites and case study and other subway system it leads from the research which it sees and signal - train in base grudge to sleep it contributes it does.

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Verification of Hybrid Structural Test Technique by Shaking Table Test of a Linear 2-Dimensional Frame Model (소형선형 평면뼈대모형의 진동대실험을 통한 하이브리드실험 기법의 검증)

  • Cho, Sung-Min;Choi, In-Gyu;Jung, Dae-Sung;Kim, Chul-Young
    • Journal of the Earthquake Engineering Society of Korea
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    • v.14 no.6
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    • pp.33-43
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    • 2010
  • This paper deals with the hybrid structural test technique which has been introduced and studied currently in Korea. In this study, a Mini-MOST system which was developed as a part of NEES research was modified and improved to reduce the total simulation time to half of the original system. Using the proposed system together with the 2 dimensional small steel frame specimen, the validity and efficiency of the hybrid test technique is investigated. Even though the hybrid test has been developed as an alternative to the shaking table test and has been studied and applied for a long time in several countries, no attempt has been made to compare it directly with the shaking table test. Therefore, in this study, the hybrid test results are compared with those of the shaking table test as well as with a numerical simulation for the verification of hybrid test. From the comparison and analysis of the test results, it is concluded that the hybrid test can simulate the actual seismic behavior of structural systems very accurately and it can be a good alternative to the shaking table test.

Influences of Internet Shopping Mall Pattern Interactivity on Satisfaction Degree and Recommendation Intention (인터넷쇼핑몰 유형별 상호작용성이 만족도와 추천의도에 미치는 영향)

  • Moon, Jae-Hak
    • The Journal of the Korea Contents Association
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    • v.10 no.1
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    • pp.239-246
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    • 2010
  • This research sees that even interactivities have differences by the types of internet shopping malls and compared and analyzed the interactivities by classifying them into open market and special malls. The research survey was conducted aiming at those who purchased products in Internet shopping malls within the latest 6 months, and, then, a statistical analysis was carried out. The analysis result showed the interactivity in internet shopping malls was deduced as 2 perspectives while it was confirmed that there are differences according to shopping mall types. For open markets, interactivities of both 'between company and customers' and 'between customers and customers' have significant influences on the satisfaction degree. Especially, the interactivity of 'between company and customers' have higher influences on the satisfaction degree. However, for the specialty malls, it was shown that only the interactivity of 'between company and customers' have significant influences on the customer satisfaction degree. Additionally, it was confirmed that the satisfaction degree toward a shopping mall has positive influence even on future recommendation intentions. Such research results confirmed that distinctive strategies which consider the patterns of shopping malls should be applied in order for a company to effectively utilize the interactivity in internet shopping mall markets.

Genetic Algorithm Based Optimal Structural Design Method for Cost and CO2 Emissions of Reinforced Concrete Frames (철근콘크리트 모멘트골조의 비용 및 이산화탄소 배출량을 고려한 유전자알고리즘 기반 구조최적화기법)

  • Lee, Min-Seok;Hong, Kappyo;Choi, Se-Woon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.29 no.5
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    • pp.429-436
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    • 2016
  • In this study, the genetic algorithm based optimal structural design method is proposed. The objective functions are to minimize the cost and $CO_2$ emissions, simultaneously. The cost and $CO_2$ emissions are calculated based on the cross-sectional dimensions, length, material strength, and reinforcement ratio of beam and column members. Thus, the cost and $CO_2$ emissions are evaluated by using the amounts of concrete and reinforcement used to construct a building. In this study, the cost and $CO_2$ emissions calculated at the phases of material transportation, construction, and building operation are excluded. The constraint conditions on the strength of beam and column members and the inter-story drift ratio are considered. The linear static analysis by using OpenSees is automatically conducted in the proposed method. The genetic algorithm is employed to solve the formulated problem. The proposed method is validated by applying it to the 4-story reinforced concrete moment frame example.

Different approaches for numerical modeling of seismic soil-structure interaction: impacts on the seismic response of a simplified reinforced concrete integral bridge

  • Dhar, Sreya;Ozcebe, Ali Guney;Dasgupta, Kaustubh;Petrini, Lorenza;Paolucci, Roberto
    • Earthquakes and Structures
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    • v.17 no.4
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    • pp.373-385
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    • 2019
  • In this article, different frequently adopted modeling aspects of linear and nonlinear dynamic soil-structure interaction (SSI) are studied on a pile-supported integral abutment bridge structure using the open-source platform OpenSees (McKenna et al. 2000, Mazzoni et al. 2007, McKenna and Fenves 2008) for a 2D domain. Analyzed approaches are as follows: (i) free field input at the base of fixed base bridge; (ii) SSI input at the base of fixed base bridge; (iii) SSI model with two dimensional quadrilateral soil elements interacting with bridge and incident input motion propagating upwards at model bottom boundary (with and without considering the effect of abutment backfill response); (iv) simplified SSI model by idealizing the interaction between structural and soil elements through nonlinear springs (with and without considering the effect of abutment backfill response). Salient conclusions of this paper include: (i) free-field motions may differ significantly from those computed at the base of the bridge foundations, thus put a significant bias on the inertial component of SSI; (ii) conventional modeling of SSI through series of soil springs and dashpot system seems to stay on the safer side under dynamic conditions when one considers the seismic actions on the structure by considering a fully coupled SSI model; (iii) consideration of abutment-backfill in the SSI model positively affects the general response of the bridge, as a result of large passive resistance that may develop behind the abutments.

Seismic Performance Evaluation of School Building Reinforced by Circular-Opening Steel Shear Wall System (원형개구부가 있는 강판 전단벽 시스템을 적용한 학교 건축물의 내진성능평가)

  • Lee, Yu-Hyeon;Lee, Swoo-Heon;Lee, Hee-Du;Shin, Kyung-Jae
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.34 no.1
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    • pp.19-26
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    • 2018
  • After the Gyeongju earthquake, school buildings were designated as earthquake shelters. However, the ratio of designed for seismic of domestic school buildings is only 23.2% in Korea, and it is necessary to secure the seismic safety of those. Therefore, in this paper, a target building was selected before the seismic design criteria was established and the seismic performance of the building was evaluated. After the evaluation, reinforcement of the building was carried out using seismic retrofit systems which was previously tested. For this purpose, the evaluation was carried out using OpenSees program and the reliability of the seismic retrofit systems was also verified. In this way, we can more precisely reproduce the response of the building in case of actual earthquake and predict damage of the earthquake in the future.