• Title, Summary, Keyword: OpenSees

Search Result 104, Processing Time 0.038 seconds

Simulation study on dynamic response of precast frames made of recycled aggregate concrete

  • Pham, ThiLoan;Xiao, Jianzhuang;Ding, Tao
    • Computers and Concrete
    • /
    • v.16 no.4
    • /
    • pp.643-667
    • /
    • 2015
  • 3-dimentional precast recycled aggregate concrete (RAC) finite element models were developed by means of the platform OpenSees to implement sophisticated nonlinear model subjected to seismic loads. Efforts were devoted to the dynamic responses (including dynamic characteristics, acceleration amplifications, displacements, story drifts) and capacity curve. In addition, this study extended the prediction on dynamic response of precast RAC model by parametric study of material properties that represent the replacement percentage of recycled coarse aggregate (RCA). Principles and assumptions that represent characteristics of precast structure and influence of the interface between head of column and cast-in-place (CIP) joint on the stiffness of the joints was put forward and validated by test results. The comparison between simulated and tested results of the precast RAC frame shows a good correlation with most of the relative errors about 25% in general. Therefore, the adopted assumptions and the platform OpenSees are a viable approach to simulate the dynamic response of precast frames made of RAC.

An Analytical Study for Structural Behaviors of Unbonded Precast Rectangular Hollow Section Concrete Piers (비부착 프리캐스트 중공 사각 단면 교각의 구조거동에 관한 해석적 연구)

  • Choi, Seung-Won;Kim, Ick-Hyun;Cho, Jae-Yeo;Chang, Sung-Pil
    • Journal of The Korean Society of Civil Engineers
    • /
    • v.30 no.1A
    • /
    • pp.61-69
    • /
    • 2010
  • Unbonded precast concrete piers have better seismic performances than conventional reinforced concrete piers. In this research, seismic performances of unbonded precast prestressed concrete piers are analyzed using OpenSEES. Main parameters of analysis are concrete strength, jacking force ratio, ratio of tendon, and size of precast segment. In results, as the ratio of tendon and jacking force ratio increase, the flexural strength increases at softening state and ultimate state. Concrete strength and size of precast segment are negligible. But initial jacking force ratio leads to early yielding of prestressing tendon. Since compressive strain in core concrete is much less than ultimate strain, it can be expected that the amount of transverse steel reinforcement is to be reduced in comparison with conventional reinforced concrete column.

Seismic Fragility Assessment Method for RC Bridges in Korea using a Representative Bridge (대표 교량을 이용한 국내 철근콘크리트 교량의 지진취약성 분석 방법)

  • An, HyoJoon;Jeong, Seong-Hoon;Shin, Soobong
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.32 no.6
    • /
    • pp.417-423
    • /
    • 2019
  • In this investigation, a set of seismic fragility curves for RC bridges in Korea is derived by considering variations of the representative analytical model. The dimensions and specifications of the model are determined, based on statistical analysis of the inventory of RC bridges in Korea. Variations of important modeling parameters such as material properties, size of structural members, and dimension of the bridge are defined based on statistical studies of the bridges. The OpenSees program is utilized for the analysis to represent the inelastic behavior of RC members. A systematic approach is developed to perform a large volume of inelastic dynamic analysis, in which continuous variation of the modeling parameters are programmed to appropriately represent the characteristics of RC bridges in Korea.

GEMINI NEAR-IR PHOTOMETRY OF THE ARCHES CLUSTER NEAR THE GALACTIC CENTER

  • YANG YUJIN;PARK HONG SOO;LEE MYUNG GYOON;LEE SANG-GAK
    • Journal of The Korean Astronomical Society
    • /
    • v.35 no.3
    • /
    • pp.131-141
    • /
    • 2002
  • We present Near-IR photometry of the Arches cluster, a young and massive stellar cluster near the Galactic center. We have analyzed the high resolution (FWHM $\~$ 0.2") Hand K' band images in the Galactic Center Demonstration Science Data Set, which were obtained with the Gemini/Hokupa's adaptive optics (AO) system. We present the color-magnitude diagram, the luminosity function and the initial mass function (IMF) of the stars in the Arches cluster in comparison with the HST/NICMOS data. The IMF slope for the range of 1.0 < log (M/M$\bigodot$) < 2.1 is estimated to be ${\Gamma} = -0.79 {\pm} 0.16$, in good agreements with the earlier result based on the HST/NICMOS data [Figer et al. 1999, ApJ, 525, 750]. These results strengthen the evidence that the IMF of the bright. stars close to the Galactic center is much flatter than that for the solar neighborhood. This is also consistent with a recent finding that the IMFs of the bright stars in young clusters in M33 get flatter as the galactocentric distance decreases [Lee et al. 2001, astro-ph 0109258]. It is found that the power of the Gemini/ AO system is comparable, with some limits, to that of the HST/NICMOS.

BOAO PHOTOMETRIC SURVEY OF GALACTIC OPEN CLUSTERS. III. CZERNIK 24 AND CZERNIK 27

  • Kim Sang-Chul;Park Hong-Soo;Sohn Sang-Mo Tony;Lee Myung-Gyoon;Park Byeong-Gon;Sung Hwan-Kyung;Ann Hong-Bae;Chun Moo-Young;Kim Seung-Lee;Jeon Young-Beom;Yuk In-Soo;Lee Sang- Hyun
    • Journal of The Korean Astronomical Society
    • /
    • v.38 no.4
    • /
    • pp.429-435
    • /
    • 2005
  • We present BV CCD photometry for the open clusters Czernik 24 and Czernik 27. These clusters have never been studied before, and we provide, for the first time, the cluster parameters; reddening, distance, metallicity and age. Czernik 24 is an old open cluster with age $1.8{\pm}0.2Gyr$, metallicity $[Fe/H]=-0.41{\pm}0.15dex$, distance modulus $(m-M)_0=13.1{\pm}0.3mag$ ($d=4.1{\pm}0.5kpc$), and reddening $E(B-V)=0.54{\pm}0.12mag$. The parameters for Czernik 27 are estimated to be $age=0.63{\pm}0.07Gyr$, $[Fe/H]=-0.02{\pm}0.10dex$, $(m-M)_0=13.8{\pm}0.2mag$ ($d=5.8{\pm}0.5kpc$), and $E(B-V)=0.15{\pm}0.05mag$. The metallicity and distance values for Czernik 24 are consistent with the relation between the metallicity and the Galactocentric distance of other old open clusters. We find the metallicity gradient of 51 old open clusters including Czernik 24 to be ${\Delta}[Fe/H]/{\Delta}R_{gc}=-0.064 {\pm}0.009dex\;kpc^{-1}$.

Non-linear time history analysis of building with torsional irregularity (비틀림비정형을 갖는 건물의 비선형 시간이력해석)

  • Lee, Han-Seon;Ko, Dong-Woo
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • /
    • pp.219-222
    • /
    • 2005
  • Many RC building structures of multiple uses constructed in Korea have the irregularities of torsion and soft story at bottom stories. A typical irregular building was selected as prototype and shaking table tests were performed to investigate the seismic performance of this building. The objective of this study is to evaluate the correlation between the experimental and analytical responses of this irregular building structure subjected to the earthquake excitation by using OpenSees(Open System for Earthquake Engineering Simulation). The results of analyses simulate well the behavior of the building having torsional irregularity and weak stories.

  • PDF

Preliminary Modelling of Plasco Tower Collapse

  • Yarlagadda, Tejeswar;Hajiloo, Hamzeh;Jiang, Liming;Green, Mark;Usmani, Asif
    • International Journal of High-Rise Buildings
    • /
    • v.7 no.4
    • /
    • pp.397-408
    • /
    • 2018
  • In a recent tragic fire incident, the Plasco Tower collapsed after an intense outburst of fire lasting for three and a half hours and claiming the lives of 16 firefighters and 6 civilians. This paper will present continuing collaborative work between Hong Kong Polytechnic University and Queen's University in Canada to model the progressive collapse of the tower. The fire started at the 10th floor and was observed to have travelled along the floor horizontally and through the staircase and windows vertically. Plasco Tower was steel structure and all the steel sections were fabricated by welding standard European channel or angle profiles and no fire protection was applied. Four internal columns carried the loads transferred by the primary beams, and box columns were constructed along the perimeter of the building as a braced tube for resisting seismic loading. OpenSees fibre-based sections and displacement-based beam-column elements are used to model the frames, while shell elements are used for the reinforced concrete floor slabs. The thermal properties and elevated temperature mechanical properties are as recommended in the Eurocodes. The results in this preliminarily analysis are based on rough estimations of the structure's configuration. The ongoing work looks at modeling the Plasco Tower based on the most accurate findings from reviewing many photographs and collected data.

Nonlinear Seismic Analysis of U-Shaped Cantilever Retaining Structures

  • Sadiq, Shamsher;Park, Duhee;Yoo, Jinkwon;Yoon, Jinam;Kim, Juhyung
    • Journal of the Korean Geoenvironmental Society
    • /
    • v.18 no.11
    • /
    • pp.27-33
    • /
    • 2017
  • Nonlinear dynamic analysis is performed to calculate the response of U-shaped cantilever retaining structure under seismic loading using the finite element (FE) analysis program OpenSees. A particular interest of the study is to evaluate whether the moment demand in the cantilever can be accurately predicted, because it is an important component in the seismic design. The numerical model is validated against a centrifuge test that was performed on cantilever walls with dry medium dense sand in backfill. Seismic analysis is performed using the pressure-dependent, multi-yield-surface, plasticity based soil constitutive model implemented in OpenSees. Normal springs are used to simulate the soil-structure interface. Comparison with centrifuge show that FE analysis provides good estimates of both the acceleration response and bending moment. The lateral earth pressure near the bottom of the wall is overestimated in the numerical model, but this does not contribute to a higher prediction of the moment.

Comparison of Nonlinear Analysis Programs for Small-size Reinforced Concrete Buildings II (소규모 철근콘크리트 건축물을 위한 비선형해석 프로그램 비교 II)

  • Yoo, Changhwan;Kim, Taewan;Park, Hong-Gun
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.19 no.5
    • /
    • pp.229-238
    • /
    • 2015
  • For small-size reinforce-concrete buildings, Midas Gen, OpenSees, and Perform-3D, which are structural analysis programs that are most popularly used at present, were applied for nonlinear static pushover analysis, and then difference between those programs was analyzed. Example buildings were limited to 2-story frames with irregular shaped walls. Analysis result showed that there were more differences than for frames only and frames with rectangular walls, but it was not so significant. Nevertheless, the capacity curve were different in some buildings, which is attributed to shape and location of walls, and feature of the analysis program. Especially, selection of automatic or manual input in Midas Gen, or nonlinear wall elements in Perform3D can affect the capacity curve and performance of the buildings. Therefore, the program users should understand the feature of the program well, and then conduct performance assessment. The result of this study is limited to low-story buildings so that it should be noted that it is possible to get different results for mid- to high-rise buildings.

Comparison of Nonlinear Analysis Programs for Small-size Reinforced Concrete Buildings I (소규모 철근콘크리트 건축물을 위한 비선형해석 프로그램 비교 I)

  • Yoo, Changhwan;Kim, Taewan
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.19 no.5
    • /
    • pp.219-228
    • /
    • 2015
  • For small-size reinforce-concrete buildings, Midas Gen, OpenSees, and Perform-3D, which are structural analysis programs that are most popularly used at present, were applied for nonlinear static pushover analysis, and then difference between those programs was analyzed. Example buildings were limited to 2-story frames only and frames with one or more rectangular walls. Analysis results showed that there was not much difference for frames only based on capacity curves. There were some differences for frames with rectangular walls, but it was not so significant. The global behaviors represented by the capacity curve were not so different, but the feature of each analysis program appeared when the results were analyzed in more detail. Therefore, the program users should understand the feature of the program well, and then conduct performance assessment. The result of this study is limited to low-story frames only and frames with rectangular walls so that it should be noted that it is possible to get different results for frames with non-rectangular walls or mid- to high-rise buildings.