• Title/Summary/Keyword: lateral load

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A lateral load pattern based on energy evaluation for eccentrically braced frames

  • Fakhraddini, Ali;Fadaee, Mohammad Javad;Saffari, Hamed
    • Steel and Composite Structures
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    • v.27 no.5
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    • pp.623-632
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    • 2018
  • Performance-Based Plastic Design (PBPD) method has been recently developed to evaluate the behavior of structures in different performance levels. The PBPD method utilizes a base shear force and a lateral load pattern that are estimated based on energy and yielding mechanism concepts. Using of current lateral force pattern results in weak structural members in upper stories of a structure so that the values of the story drift in these stories are larger than the target drift, particularly in high-rise buildings. Therefore, such distribution requires modifications to overcome this drawback. This paper proposes a modified lateral load pattern for steel Eccentrically Braced Frames (EBFs) based on parametric study. In order to achieve the modified load pattern, a group of 26 EBFs has been analyzed under a set of 20 earthquake ground motions. Additionally, results of nonlinear dynamic analyses of EBFs have been post-processed by nonlinear regression analysis in order to derive the new load pattern. To prove the efficiency of present study, three EBFs as examples were designed by modified pattern and current PBPD distribution. Inelastic dynamic analyses results showed that the story drifts using modified lateral load pattern were well within the target values in comparison with current pattern in PBPD, particularly where the effect of the height is significant. The modified load pattern reduces the possibility of underdesigning in upper levels and overdesigning in lower levels of the frames.

Experiment of Lateral Load Resistance of Dori-Directional Frame in Traditional Wood Structure System (전통목구조 시스템의 도리방향 골조의 횡저항 성능에 대한 실험)

  • Lee, Young-Wook;Hong, Sung-Gul;Kim, Nam-Hee;Jung, Sung-Jin;Hwang, Jong-Kook;Bae, Boung-Sun
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2007.04a
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    • pp.241-246
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    • 2007
  • The capacity of a lateral load resistance of a joint with Jangbu-connection of Dori-directional frame in traditional wood structure system was studied, through experiments of 1/2 scaled and T-shaped 7 subassemblies of joint of Dori-directional frame for Deawoongjeon of Bongjungsa. From the experiment, it was shown that the capacity of a lateral load resistance was influenced by the vertical load confining joint and not influenced by the number of Chok and the depth of Changbang, And lateral load resistance mechanism is developed by the restraint between the vertical load and the contacting edge of column; if structure is pushed to the left, the top-right end of Pyeongju contacts with Changbang and left Changbang loses the contacts with Pyeongju and therefore only right Changbang can resist to lateral load.

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Effect of loading rate on mechanical behavior of SRC shearwalls

  • Esaki, Fumiya;Ono, Masayuki
    • Steel and Composite Structures
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    • v.1 no.2
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    • pp.201-212
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    • 2001
  • In order to investigate the effect of the loading rate on the mechanical behavior of SRC shearwalls, we conducted the lateral loading tests on the 1/3 scale model shearwalls whose edge columns were reinforced by H-shaped steel. The specimens were subjected to the reversed cyclic lateral load under a variable axial load. The two types of loading rate, 0.01 cm/sec for the static loading and 1 cm/sec for the dynamic loading were adopted. The failure mode in all specimens was the sliding shear of the in-filled wall panel. The edge columns did not fail in shear. The initial lateral stiffness and lateral load carrying capacity of the shearwalls subjected to the dynamic loading were about 10% larger than those subjected to the static loading. The effects of the arrangement of the H-shaped steel on the lateral load carrying capacity and the lateral load-displacement hysteresis response were not significant.

Fire performance curves for unprotected HSS steel columns

  • Shahria Alam, M.;Muntasir Billah, A.H.M.;Quayyum, Shahriar;Ashraf, Mahmud;Rafi, A.N.M.;Rteil, Ahmad
    • Steel and Composite Structures
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    • v.15 no.6
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    • pp.705-724
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    • 2013
  • The behaviour of steel column at elevated temperature is significantly different than that at ambient temperature due to its changes in the mechanical properties with temperature. Reported literature suggests that steel column may become vulnerable when exposed to fire condition, since its strength and capacity decrease rapidly with temperature. The present study aims at investigating the lateral load resistance of non-insulated steel columns under fire exposure through finite element analysis. The studied parameters include moment-rotation behaviour, lateral load-deflection behaviour, stiffness and ductility of columns at different axial load levels. It was observed that when the temperature of the column was increased, there was a significant reduction in the lateral load and moment capacity of the non-insulated steel columns. Moreover, it was noted that the stiffness and ductility of steel columns decreased sharply with the increase in temperature, especially for temperatures above $400^{\circ}C$. In addition, the lateral load capacity and the moment capacity of columns were plotted against fire exposure time, which revealed that in fire conditions, the non-insulated steel columns experience substantial reduction in lateral load resistance within 15 minutes of fire exposure.

Effect of Relative Density on Lateral Load Capacity of a Cyclic Laterally Loaded Pile in Sandy Soil (모래지반의 상대밀도에 따른 횡방향 반복재하 시 말뚝의 극한지지력 평가)

  • Baek, Sung-Ha;Kim, Joon-Young;Lee, Seung-Hwan;Chung, Choong-Ki
    • Journal of the Korean Geotechnical Society
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    • v.32 no.4
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    • pp.41-49
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    • 2016
  • Pile foundations used as offshore support structures are dominantly subjected to cyclic lateral loads due to wind and waves. In this study, a series of cyclic lateral load tests were performed on a pre-installed aluminum flexible pile in sandy soil with three different relative densities (40%, 70% and 90%) in order to evaluate the effect of cyclic lateral loads on lateral load capacity of a pile. The cyclic lateral loads increased the lateral load capacity of a pile at 40% relative density, whereas they decreased it at 70% and 90% relative densities. This can be explained by the fact that the cyclic lateral loads slightly densified the surrounding soil in relatively loose sand (40%), while the surrounding soil was disturbed in relatively dense sand (70% and 90%). These effects were more obvious as the cyclic lateral load amplitude increased, being independent with the saturation. Also, from the test results, an empirical equation for the lateral load capacity of a cyclic laterally loaded pile in sandy soil was developed in terms of relative density of the soil and the cyclic lateral load amplitude.

Analysis of Lateral Earth Pressures on Retaining Wall from Traffic Load Distribution (옹벽 상단 교통하중의 분포에 따른 옹벽의 수평 토압 분석)

  • Lee, Kicheol;Kim, Dongwook;Chung, Moon-Kyung
    • Journal of the Korean Geosynthetics Society
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    • v.16 no.4
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    • pp.43-55
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    • 2017
  • The purpose of this study is to investigate the effect of traffic loads on retaining wall stability. There is insufficient research on lateral earth pressure on retaining wall due to traffic load. In addition, limited detailed designs of retaining wall for transportation including number of lanes of road, magnitudes of axle loads, and vehicle formations are available. Because the lateral earth pressure on the retaining wall due to traffic loads is a function of the lateral distance from retaining wall, the wall height, and the locations of lanes, the analysis of lateral load on retaining wall from traffic loads is performed with direct or indirect reflection of these factors. As a result of the analysis, lateral earth loads induced from traffics can be considered negligible if the lateral distance of traffic load from wall exceeds the height of retaining wall. Therefore, it is practically reasonable to consider traffic loads within a lateral distance between wall and traffic load of the height of retaining wall.

Behavior of Laterally Cyclic Loaded Piles Driven into Sand (모래지반에서 반복수평하중을 받는 항타말뚝의 거동)

  • Paik, Kyu-Ho;Park, Won-Woo;Kim, Young-Jun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.913-922
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    • 2009
  • Fourteen model pile load tests using a calibration chamber and instrumented model pile were preformed to investigate the variation of the behaviors of driven piles in sands with soil and lateral cyclic loading conditions. Results of the model tests showed that the first loading cycle generated more than 70% of the pile head rotation developed for 50 lateral loading cycles. Lateral cyclic loading also made an increase of the ultimate lateral load capacity of piles for $K_0$=0.4 and an decrease for $K_0$ higher than 0.4. Higher portion of the increase or decrease in the ultimate lateral load capacity by lateral cyclic loading was generated for the first loading cycle due to densification of loosening of the soil around the pile by lateral cyclic loading. It was also observed that a two-way cyclic loading caused higher ultimate lateral load capacity of driven piles than a one-way cyclic loading. When the pile was in the ultimate state, the maximum bending moment developed in the pile increased with increasing $K_0$ value of soil and was insensitive to the magnitude and number of lateral cyclic loading.

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Experimental Study on the Behavior Characteristics of Single Steel Pile in Sand Subjected to Lateral Loadings (사질토 지반에서 수평하중에 따른 단일강관말뚝의 거동특성에 관한 실험적 연구)

  • Kim, Daehyeon;Lee, Tae-Gwang;Kim, Sun-Hak
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.5
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    • pp.3548-3556
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    • 2015
  • In order to fulfill the needs of reliable and economically feasible foundation, engineers should consider not only the working load that can endure extreme conditions but also apprehending precise behavior of continuous dynamic load while designing the foundation of offshore wind power generators. To actualize the foundation, a model pile was made in miniature. Also, calibration chamber was made and a 500mm height of sand-bed was made to perform "static lateral load experiment" and "repetitive loading experiment", total of two Lateral load tests. As a result, in Static Lateral load test, the bigger length/diameter of model pile led an increase in load displacement. However, when performing "Cyclic Lateral load test", the increase in number of under loading led the decrease in horizontal displacement from each repeated lateral load. While performing Static Lateral load test and repeated loading experiment, we could observe the decreasing in the rate of ultimate lateral load capacity increase of the pile. Also, it turned out that the higher relative density of the ground, the lower ultimate lateral load capacity by repeated horizontal loading.

Safety evaluation of tilting train on circular curve (틸팅열차의 원곡선부 주행시 안전성 평가)

  • Kim, Sang-Soo;Eum, Ki-Young;Bae, Jae-Hyoung
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.1703-1712
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    • 2010
  • The safety of tilting train running on curved track is, in general, evaluated with a derailment coefficient calculated by the ratio of wheel load and lateral force, Particularly on curve, the wheel load and lateral force on rail may cause trackbed to be deformed, depending on their intensity, and moreover, often result in critical accident such as derailment. This study hence was intended to identify the cause of wheel load and lateral force so as to suggest the allowable wheel load reduction rate, lateral force limit and derailment coefficient, thereby quantitatively evaluating the operational safety of tilting train. This study therefore was aimed to analyze the wheel load and lateral force occurred during tilting train's operation on circular curve in such a way of comparing with traditional trains, by axle and speed, in a bid to eventually evaluate the operational safety of tilting train.

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Evaluation of Inelastic Displacement Response of Bridge Structures Using Lateral Load Distributions (횡하중 분배방법을 이용한 교량구조물의 비탄성 변위응답 평가)

  • Song, Jong-Keol;Nam, Wang-Hyun;Chung, Yeong-Hwa
    • Journal of Industrial Technology
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    • v.25 no.A
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    • pp.15-22
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    • 2005
  • In order to evaluate seismic performance of multi-degree-of-freedom bridge structure, moderate lateral load distribution methods using the pushover analysis were developed by many researchers. One of important variables to improve an accuracy of pushover analysis is lateral load distribution. In this study, pushover analyses were performed using the five types of lateral load distribution and seismic performances were evaluated by capacity spectrum method (CSM). To verify an accuracy of suggested lateral load distribution, the maximum displacement estimates by the CSM were compared to those by inelastic time history analysis.

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