• Title, Summary, Keyword: lateral stiffness

Search Result 771, Processing Time 0.042 seconds

Finite Element Analysis for the Effects on the Stiffness of the Embankment and Sandmat on the Deformation Property and the Safety of Road Embankment (성토체 및 모래매트의 강성이 하부지반의 변형과 성토체의 안전에 미치는 영향에 대한 유한요소해석)

  • Bae, Woo-Seok;Kim, Jong-Woo;Kwon, Young-Cheul
    • Journal of the Korean Society of Safety
    • /
    • v.22 no.4
    • /
    • pp.57-65
    • /
    • 2007
  • Effects on the stiffness of the embankment and sandmat on the construction safety of road embankment was investigated in this study by the numerical experiments using FEM. Two points was mainly focused in this study especially. First the deformation characteristics by the change of the stiffness of sand mat and embankment was investigated by the analyzing the consolidation settlement at the center of the embankment and the lateral displacement at the toe of the embankment. And, the effect of the stiffness on the stress distribution characteristics was also investigated in this study. Furthermore, slope stability analysis was carried out to gain the safe factor by change the stiffness of the sandmat and the embankment. The objective of the study is supplying the result of the numerical experiments for the geotechnical engineers who use the FEM for the safety design of the soil structures. As a result, the stiffness of the superstructures greatly affects on the deformation characteristics both in consolidation settlement and lateral displacement. However, it can be aware that it is not dominants to the stress distribution in the aspect that the no changes in the residual excess pore water pressure. Therefore, the decision of the stiffness has to be carried out deliberately considering not only the consolidation the magnitude of the settlement and the lateral displacement, but the slope stability.

A Study on Determination of the Minimum Vertical Spring Stiffness of Track Pads in Korea High Speed Railway. (고속철도 궤도패드의 최소 수직 스프링계수 결정에 관한 연구)

  • Kim Jeong-il;Yang Sin-Chu;Kim Yun-Tae;Suh Sa-Bum
    • Proceedings of the KSR Conference
    • /
    • /
    • pp.504-509
    • /
    • 2005
  • Railway noise and vibration has been recognized as major problems with the speed-up of rolling stock. As a kind of solution to these problems, the decrease of stiffness of track pad have been tried. However, in this case, overturning of rail due to lateral force should be considered because it can have effect on the safety of running train. Therefore, above two things - decrease of stiffness of track pad and overturning of rail due to lateral force - should be considered simultaneously for the appropriate determination of spring coefficient of track pad. With this viewpoint, minimum spring coefficient of track pad is estimated through the comparison between the theoretical relationship about the overturning of rail and 3-dimensional FE analysis result. Two kinds of Lateral force and wheel load are used as input loads. Extracted values from the conventional estimation formula and the Shinkansen design loads are used. It is found that the overturning of rail changes corresponding to the change of the stiffness of track pad and the ratio of lateral force to wheel load. Moreover, it is found that the analysis model can have influence on the results. Through these procedure, minimum spring coefficient of track pad is estimated.

  • PDF

Effect of rigid connection to an asymmetric building on the random seismic response

  • Taleshian, Hamed Ahmadi;Roshan, Alireza Mirzagoltabar;Amiri, Javad Vaseghi
    • Coupled systems mechanics
    • /
    • v.9 no.2
    • /
    • pp.183-200
    • /
    • 2020
  • Connection of adjacent buildings with stiff links is an efficient approach for seismic pounding mitigation. However, use of highly rigid links might alter the torsional response in asymmetric plans and although this was mentioned in the literature, no quantitative study has been done before to investigate the condition numerically. In this paper, the effect of rigid coupling on the elastic lateral-torsional response of two adjacent one-story column-type buildings has been studied by comparison to uncoupled structures. Three cases are considered, including two similar asymmetric structures, two adjacent asymmetric structures with different dynamic properties and a symmetric system adjacent to an adjacent asymmetric one. After an acceptable validation against the actual earthquake, the traditional random vibration method has been utilized for dynamic analysis under Ideal white noise input. Results demonstrate that rigid coupling may increase or decrease the rotational response, depending on eccentricities, torsional-to-lateral stiffness ratios and relative uncoupled lateral stiffness of adjacent buildings. Results are also discussed for the case of using identical cross section for all columns supporting eachplan. In contrast to symmetric systems, base shear increase in the stiffer building may be avoided when the buildings lateral stiffness ratio is less than 2. However, the eccentricity increases the rotation of the plans for high rotational stiffness of the buildings.

Stiffness Reduction Factor for Post-Tensioned Flat Plate Slabs (포스트 텐션 플랫 플레이트 해석을 위한 강성감소계수)

  • Park, Young-Mi;Park, Jin-Ah;Han, Sang-Whan
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • /
    • pp.125-126
    • /
    • 2009
  • Effective beam width model (EBWM) has been used for analysis of post-tensioned (PT) flat plate slab frames under lateral loads. For analyzing PT flat plate slab structure under lateral loads with good precision, reduction in slab stiffness has to be accurately estimated for Effective beam width model(EBWM). For this purpose, this study collected test results of PT flat plate system conducted by former researches. And this study reduced the width of slab so that the stiffness of the EBWM converged into the lateral stiffness of each test specimens by trial and error. By conducting nonlinear regression analysis, an equation for calculating stiffness reduction factor for the PT flat plate is proposed.

  • PDF

Structural Analysis for Determination of Optimal Outrigger Location in Core and Offset Outrigger System (코어 및 오프셋 아웃리거 구조시스템의 최적 아웃리거 위치 결정을 위한 구조해석)

  • Lee, Sang-Ho;Kim, Hyong-Kee
    • Journal of the Regional Association of Architectural Institute of Korea
    • /
    • v.20 no.5
    • /
    • pp.45-52
    • /
    • 2018
  • The aim of this study is to search the optimum location of core and offset outrigger system in high-rise building. To achieve this objective, a structural schematic design of 80 stories building was carried out by making use of MIDAS-Gen. In this paper, the main variables of structural analysis research were the outrigger stiffness, the lateral stiffness ratio between rigid frame and shear wall, the outrigger location in plan and the outrigger location in height. For the goal of finding out the optimal location of core and offset outrigger system in tall building, we analyzed the lateral displacement in top level which is the very important parameter in the structure design of high-rise building. The study results showed that the outrigger location in plan, outrigger location in height, outrigger stiffness and lateral stiffness ratio between rigid frame and shear wall, had an effect on the optimal position of outrigger system. Also, it is considered that the paper results can be helpful in getting the structure design materials for finding out the optimal of location core and offset outrigger system in tall building.

Cyclic tests of steel frames with composite lightweight infill walls

  • Hou, Hetao;Chou, Chung-Che;Zhou, Jian;Wu, Minglei;Qu, Bing;Ye, Haideng;Liu, Haining;Li, Jingjing
    • Earthquakes and Structures
    • /
    • v.10 no.1
    • /
    • pp.163-178
    • /
    • 2016
  • Composite Lightweight (CL) insulated walls have gained wide adoption recently because the exterior claddings of steel building frames have their cost effectiveness, good thermal and structural efficiency. To investigate the seismic behavior, lateral stiffness, ductility and energy dissipation of steel frames with the CL infill walls, five one-story one-bay steel frames were fabricated and tested under cyclic loads. Test results showed that the bolted connections allow relative movement between CL infill walls and steel frames, enabling the system to exhibit satisfactory performance under lateral loads. Additionally, it is found that the addition of diagonal steel straps to the CL infill wall significantly increases the initial lateral stiffness, load-carrying capacity, ductility and energy dissipation capacity of the system. Furthermore, the test results indicate that the lateral stiffness values of the frames with the CL infill wall are similar to those of the bare steel frames in large lateral displacement.

Numerical study on the moment capacity of zed-section purlins under uplift loading

  • Zhu, Jue;Chen, Jian-Kang;Ren, Chong
    • Structural Engineering and Mechanics
    • /
    • v.49 no.2
    • /
    • pp.147-161
    • /
    • 2014
  • In this paper a nonlinear finite element analysis model is established for cold-formed steel zed-section purlins subjected to uplift loading. In the model, the lateral and rotational restraints provided by the sheeting to the purlin are simplified as a lateral rigid restraint imposed at the upper flange-web junction and a rotational spring restraint applied at the mid of the upper flange where the sheeting is fixed. The analyses are performed by considering both geometrical and material nonlinearities. The influences of the rotational spring stiffness and initial geometrical imperfections on the uplift loading capacity of the purlin are investigated numerically. It is found that the rotational spring stiffness has significant influence on the purlin performance. However, the influence of the initial geometric imperfections on the purlin performance is found only in purlins of medium or long length with no or low rotational spring stiffness.

A new lateral load pattern for pushover analysis in structures

  • Pour, H. Gholi;Ansari, M.;Bayat, M.
    • Earthquakes and Structures
    • /
    • v.6 no.4
    • /
    • pp.437-455
    • /
    • 2014
  • Some conventional lateral load patterns for pushover analysis, and proposing a new accurate pattern was investigated in present research. The new proposed load pattern has load distribution according weight and stiffness variation in height and mode shape of structure. The assessment of pushover application with mentioned pattern in X type braced steel frames and steel moment resisting frames, with stiffness and mass variation in height, was studied completely and the obtained results were compared with nonlinear dynamic analysis method (including time history analysis). The methods were compared from standpoints of some basic parameters such as displacement, drift and shape of lateral load pattern. It is concluded that proposed load pattern results are closer to nonlinear dynamic analysis (NDA) compared to other pushover load patterns especially in tall and medium-rise buildings having different stiffness and mass during the height.

Lateral Drift Control of 3-D Steel Structures Using Approximation Concept (근사화 개념을 이용한 삼차원 철골조 구조물의 횡변위 제어에 관한 연구)

  • Lee, Han-Joo;Lim, Young-Do;Kim, Ho-Soo
    • 한국공간정보시스템학회:학술대회논문집
    • /
    • /
    • pp.96-102
    • /
    • 2004
  • This study presents an effective stiffness-based optimal technique to control quantitatively lateral drift for 3-D steel frameworks subject to lateral loads. To this end, the displacement sensitivity depending on behavior characteristics of 3-D steel frameworks is established. Also, approximation concept that can preserve the generality of the mathematical programming and can efficiently solve large scale problems is introduced. Resizing sections in the stiffness-based optimal design are assumed to be uniformly varying in size. Two types of 30-story frames are presented to illustrate the features of the Quantitative lateral drift control technique proposed in this study.

  • PDF