• Earthquakes and Structures
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• v.11 no.4
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• pp.609-627
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• 2016

Results of an experimental program are presented in this paper for the influence of vertical load on the in-plane behavior of masonry infilled steel frames. Five half-scaled single-story, single-bay steel frame specimens were tested under cyclic lateral loading. The specimens included four infilled frames and one bare frame. Two similar specimens as well as the bare frame had moment-resisting steel frames, while the remaining two specimens had pinned steel frames. For each frame type, one specimen was tested under simultaneous vertical and lateral loading, whereas the other was subjected only to lateral loading. The experimental results show that the vertical load changes the cracking patterns and failure modes of the infill panels. It improves dissipated hysteresis energy and equivalent viscous damping. Global responses of specimens, including stiffness and maximum strength, do no change by vertical loading considerably. Regarding the ductility, the presence of vertical load is ignorable in the specimen with moment-resisting frame. However, it increases the ductility of the infilled pinned frame specimen, leading to an enhancement in the m-factor by at least 2.5 times. In summary, it is concluded that the influence of the vertical load on the lateral response of infilled frames can be conservatively ignored.

• Structural Engineering and Mechanics
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• v.59 no.4
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• pp.653-669
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• 2016

Recent earthquakes worldwide show that a significant portion of the earthquake shaking happens in the vertical direction. This phenomenon has raised significant interests to consider the vertical ground motion during the seismic design and assessment of the structures. Strong vertical ground motions can alter the axial forces in the columns, which might affect the shear capacity of reinforced concrete (RC) members. This is particularly important for non-ductile RC frames, which are very vulnerable to earthquake-induced collapse. This paper presents the detailed nonlinear dynamic analysis to quantify the collapse risk of non-ductile RC frame structures with varying heights. An array of non-ductile RC frame architype buildings located in Los Angeles, California were designed according to the 1967 uniform building code. The seismic responses of the architype buildings subjected to concurrent horizontal and vertical ground motions were analyzed. A comprehensive array of ground motions was selected from the PEER NGA-WEST2 and Iran Strong Motions Network database. Detailed nonlinear dynamic analyses were performed to quantify the collapse fragility curves and collapse margin ratios (CMRs) of the architype buildings. The results show that the vertical ground motions have significant impact on both the local and global responses of non-ductile RC moment frames. Hence, it is crucial to include the combined vertical and horizontal shaking during the seismic design and assessment of non-ductile RC moment frames.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1994.04a
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• pp.120-127
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• 1994

Noise and vibration induced by subway operation are one of the major factor which annoy residents living near railway tracks. While lateral vibration is a major factor in analyzing seismic effect of the structure, vertical vibration became a major concern in considering the subway induced vibration because relatively smaller energy affects only nearby areas than that of earthquake. A characteristics of structural response induced by subway operation has been studied with different total height of the building and different number of spans. Also the frame with different span length has been studied. As the numbers of degrees freedom increase the higher mode effect on vertical vibration increases. Accordingly, the total affecting vertical modes are distributive as the numbers of degrees of freedom increase. Though the total degree of freedom increases, only some of the dominant modes actively affects to the vertical response of the structure. A frame with the number of equal spans could be analyzed by replacing the whole frame as one when we want to predict the response of the vertical vibration. Also it has been found that the seperate frame analysis will give little different result when adjacent span is relatively longer than others.

• International Journal of High-Rise Buildings
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• v.9 no.4
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• pp.307-314
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• 2020

High-rise buildings with vertical setback are widely used in practice. From the field investigation of the past earthquakes, it was found that such kind of vertically irregular high-rise building structures easily suffer severe damage during strong earthquakes. This paper presents an extensive study on the earthquake responses of moment-resisting frame structures (MFS) popularly applied in high-rise buildings with vertical setback. Four groups of MFS are designed, including three groups of structures with vertical setback and one group of structures with the lateral stiffness varying along the building height but without vertical setback. The numerical models of the structures are established, and the time history analysis of the structures under different levels of earthquakes is conducted. The earthquake responses of the structures are compared. The influence of the ratio between the horizontal setback dimension and the previous plan dimension, the eccentricity of setback, and the position where the setback occurs on the seismic performance of structures is studied. The rationality of the provisions for the structures with vertical setback specified in the current design codes is checked by the findings from this study.

• Earthquakes and Structures
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• v.11 no.3
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• pp.407-420
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• 2016

The aim of this study is to investigate the effect of vertical ground motion (VGM) on seismic behavior of reinforced concrete (RC) regular frame with construction joints, and determine more proper modeling method for cast-in-situ RC frame. The four-story RC frames in the regions of 7, 8 and 9 earthquake intensity were analyzed with nonlinear dynamic time-history method. Two different methods of ground motion input, horizontal ground motion (HGM) input only, VGM and HGM input simultaneously were performed. Seismic responses in terms of the maximum vertex displacement, the maximum inter-story drift distribution and the plastic hinge distribution were analyzed. The results show that VGM might increase or decrease the horizontal maximum vertex displacement depending on the value of axial load ratio of column. And it will increase the maximum inter-story drift and change its distribution. Finally, proper modeling method is proposed according to the distribution of plastic hinges, which is in well agreement with the actual earthquake damage.

• The Mathematical Education
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• v.29 no.1
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• pp.63-68
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• 1990

Let M be a differentiable manifold, TM its tangent bundle and FM its frame bundle. The theory of complete lifts and Horizontal lifts to FM of vector fields on M ahs been studied by many authors. Tn this paper, vertical lifts of functions vector fields md 1-forms on M to FM are studied.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.2 s.233
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• pp.270-276
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• 2005

This paper develops the flexible computational model of a heavy truck by interfacing the frame modeled as a flexible body to the heavy truck's computational model composed of rigid bodies. The frame is modeled by the finite element method. Three torsional modes and three bending modes of the frame are considered for the interface of the heavy truck's computational model. The actual vehicle test is conducted off road with a velocity of 20km/h. The vertical accelerations at the cab and front axle are measured in the test. For the verification of the developed computational model, the measured vertical acceleration profiles are compared with the simulation results of the heavy truck's flexible computational model. E grade irregular road profile of ISO is used as an excitation input in the simulation. The verified flexible computational model is used to compare the vibration characteristics of a front suspension system having a multi-leaf spring and that having a tapered leaf spring. The comparison results show that the front suspension having a tapered leaf spring has a higher vertical acceleration at the front axle but a lower vertical acceleration at the cab than the suspension system having a multi-leaf spring.

• Interaction and multiscale mechanics
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• v.4 no.4
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• pp.321-336
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• 2011

This paper presents the results of static vertical load tests carried out on a model building frame supported by pile groups embedded in cohesionless soil (sand). The effect of soil interaction on displacements and rotation at the column base and also the shears and bending moments in the columns of the building frame were investigated. The experimental results have been compared with those obtained from the finite element analysis and conventional method of analysis. Soil nonlinearity in the lateral direction is characterized by the p-y curves and in the axial direction by nonlinear vertical springs along the length of the piles (${\tau}-z$ curves) at their tips (Q-z curves). The results reveal that the conventional method gives the shear force in the column by about 40-60%, the bending moment at the column top about 20-30% and at the column base about 75-100% more than those from the experimental results. The response of the frame from the experimental results is in good agreement with that obtained by the nonlinear finite element analysis.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.1 s.178
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• pp.166-173
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• 2006

This paper investigated strength of a bogie frame for Korean tilting train that is being developed in KRRI. In this study, static load tests based on Japanese Industrial Standard (JIS) were performed. In order to simulate vertical and lateral components generated by tilting link mechanism, four hydraulic actuators were used. The eight load cases such as vertical, lateral, traction, braking and driving gear loads were applied for evaluation of the strength of bogie frame. The stresses measured at the stress concentration points were assessed using Goodman diagram. From the experimental results, structural safety of the bogie frame could be ensured.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.681-682
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• 2016

In this study we propose a novel approach to segment a terrain in two parts: ground and none-ground. The terrain is gained by a multi-channel 3D laser range sensor. We process each vertical line in each frame data. The vertical line is bounded by the sensor's position and a point in the largest circle of the frame. We consider each pair of two consecutive points in each line to find begin-ground and end-ground points. All points placed between a begin-ground point and an end-ground point are ground ones. The other points are none-ground. After examining all vertical lines in the frame, we obtain the terrain segmentation result.