• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.619-627
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• 2005

An initial member sections of steel structures is selected by experience of expert building structural designers. And appropriate member section is designed by repeat calculation through structural analysis. Therefore an initial assumption of member section is necessary for saving the time for structural design and is important to acquire safety of building structures. Also brace damper are generally used to prevent or decrease structural damage by its hysteretic behavior in building structures subjected to strong earthquake. Based on plastic design, the initial section of members for architectural steel structures with brace hysteretic dampers is presented and seismic effect of structural behavior by the ratio of damper stiffness to structural story stiffness is estimated in this paper.

• Structural Monitoring and Maintenance
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• v.5 no.1
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• pp.129-150
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• 2018

This paper presents the structural performance monitoring of an urban footbridge located in Hangzhou, China. The structural health monitoring (SHM) system is designed and implemented for the footbridge to monitor the structural responses of the footbridge and to ensure the structural safety during the period of operation. The monitoring data of stress and displacement measured by the fiber Bragg grating (FBG)-based sensors installed at the critical locations are used to analyze and assess the operation performance of the footbridge. A linear regression method is applied to separate the temperature effect from the stress monitoring data measured by the FBG-based strain sensors. In addition, the static vertical displacement of the footbridge measured by the FBG-based hydrostatic level gauges are presented and compared with the dynamic displacement remotely measured by a machine vision-based measurement system. Based on the examination of the monitored stress and displacement data, the structural safety evaluation is executed in combination with the defined condition index.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.04a
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• pp.50-57
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• 1999

Structural analysis of large-scale structures involving large amount of computational load and data storage requires high-performance computing resources. We have previously developed PC-level distributed structural analysis algorithms based on substructuring technique where each personal computer assigned to a slave node has been involved in the computations for single substructures. Recently, it has been proved by the authors that the performance of distributed structural analysis algorithm can be further enhanced by changing substructuring schemes. Therefore a new distributed structural analysis algorithm with one PC to multiple substructures scheme is presented in this paper. The algorithm is implemented on the network of multiple personal computers and applied to structural analysis of two dimensional frame structures.

• International Journal of High-Rise Buildings
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• v.3 no.3
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• pp.185-190
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• 2014

Based on a 405m high super-tall building, the influence of outriggers, different shapes and layouts of structural plane and elevation on structural efficiency under lateral forces is studied in this paper. A calculation formula concerning the structural efficiency is given. The study shows that structural efficiency can be improved by triangulating the plane shape, using mega columns, the peripherization of the plane layout, tapering the elevation shape and setting bracing structure in the elevation. The arrangement of outriggers between the core tube and flange frame can reduce the shear lag effect in order to improve structural efficiency. The essence of improving structural efficiency of super-tall buildings is to maximize the plane bending stiffness and to make its deformation approach to plane section assumption.

• Computational Structural Engineering : An International Journal
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• v.1 no.1
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• pp.71-80
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• 2001

A reliability approach to evaluate structural performance has gained increased acceptability and usage over the past two decades. Most reliability analyses are based on the reliability of an individual component without examining the entire structural system. These analyses often result in either unnecessary repairs or unsafe structures. This study uses examples of series, parallel, and series-parallel models of structural systems to illustrate how the component reliabilities affect the reliability of the entire system. The component-system reliability interaction can be used to develop optimum lifetime inspection and repair strategies for structural systems. These examples demonstrate that such strategies must be based on the reliability of the entire structural system. They also demonstrate that the location of an individual component in the system has a profound effect on the acceptable reliability of that component. Furthermore, when a structure is deteriorating over time, the reliability importance of various components is a1so changing with time. For this reason, the most critical component in the early life of the structure may not tie the most critical later.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.4
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• pp.5-12
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• 2003

This paper discusses about the thickness effects on the structural durability of a bileaflet mechanical heart valve (MHV). In the study on the design and the mechanical characteristics of a bileaflet mechanical heart valve, the fluid mechanics analysis on the blood flow passing through leaflets, the kinetodynamics analysis on the rigid body motion of the leaflet induced by the pulsatile blood flow, and the structural mechanics analysis for the deformed leaflet are required sequentially and simultaneously. Fluid forces computed in the fluid mechanics analysis on the blood flow are used in the kinetodynamics analysis for the leaflet motion. Thereafter, the structural mechanics analysis for the deformed leaflet follows to predict the structural strength variation of the leaflet as the leaflet thickness changes. Analysis results show that structural deformations and stresses increase as the fluid pressure increases and the leaflet thickness decreases. Analysis results also show that the leaflet becomes structurally weaker and weaker as the leaflet becomes thinner and thinner.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.1
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• pp.45-52
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• 2009

In this paper, a guideline for designing breakwater in wave loads and in seismic loads is proposed. A simple model structure in breaking wave zone is examined using Morison equation in consideration with the effect of an impact load, for evaluation of the wave loads. As the impact load effect is not significant, pressure distributions according to Goda are applied for evaluation of wave loads on breakwater. Structural behavior of breakwater in wave loads can be obtained using the Goda method, as well. For seismic analysis, Ofunato and Hachinohe models, as well as an artificial seismic acceleration loads model, are adopted. Soil-structure interaction analysis is carried out to find the seismic load effect. It is found that, in certain cases, structural deformation in wave loads is in the same level as deformation that in seismic loads. Thus, it is our recommendation that these two loads are considered at the same level in breakwater design.

• Geomechanics and Engineering
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• v.23 no.2
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• pp.139-149
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• 2020

Piles are widely used in structural foundations of engineering projects. However, the deformation of the soil around the pile caused by driving process has an adverse effect on adjacent existing underground buildings. Many previous studies have addressed related problems in sand and saturated clay. Nevertheless, the failure mechanism of pile driving in unsaturated soil remains scarcely reported, and this issue needs to be studied. In this study, a modeling test system based on particle image velocimetry (PIV) was developed for studying deformation characteristics of pile driving in unsaturated silt with different water contents. Meanwhile, a series of direct shear tests and soil-water characteristic curve (SWCC) tests also were conducted. The test results show that the displacement field shows an apparent squeezing effect under the pile end. The installation pressure and displacement field characteristics are sensitive to the water content. The installation pressure is the largest and the total displacement field is the smallest, for specimens compacted at water content of 11.5%. These observations can be reasonably interpreted according to the relevant unsaturated silt theory derived from SWCC tests and direct shear tests. The variation characteristics of the soil displacement field reflect the macroscopic mechanical properties of the soil around the pile.

• Steel and Composite Structures
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• v.17 no.4
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• pp.405-429
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• 2014

In this paper, it is aimed to determine the structural behavior of suspension bridges considering construction stages and different soil conditions. Bosporus Suspension Bridge connecting the Europe and Asia in Istanbul is selected as an example. Finite element model of the bridge is constituted using SAP2000 program considering existing drawings. Geometric nonlinearities are taken into consideration in the analysis using P-Delta large displacement criterion. The time dependent material strength of steel and concrete and geometric variations is included in the analysis. Time dependent material properties are considered as compressive strength, aging, shrinkage and creep for concrete, and relaxation for steel. To emphases the soil condition effect on the structural behavior of suspension bridges, each of hard, medium and soft soils are considered in the analysis. The structural behavior of the bridge at different construction stages and different soil conditions has been examined. Two different finite element analyses with and without construction stages are carried out and results are compared with each other. At the end of the analyses, variation of the displacement and internal forces such as bending moment, axial forces and shear forces for bridge deck and towers are given in detail. Also, displacement and stresses for bridge foundation are given with detail. It can be seen from the analyses that there are some differences between both analyses (with and without construction stages) and the results obtained from the construction stages are bigger. It can be stated that the analysis without construction stages cannot give the reliable solutions. In addition, soil condition have effect on the structural behavior of the bridge. So, it is thought that construction stage analysis using time dependent material properties, geometric nonlinearity and soil conditions effects should be considered in order to obtain more realistic structural behavior of suspension bridges.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.1
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• pp.29-40
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• 1999

High-rise building for dwelling has many factors to be considered in structural aspects. In particular, the higher the building, the bigger the lateral loads such as wind and earthquake due to its dynamic characteristics. Unlike the wind load, the earthquake load, even if the shape of the structures are similar, depends on structural characteristics and it is difficult to predict. For an apartment building, the water tank in the penthouse, due to its heavy weight, changes the behavior of a building when the earthquake occurs. The purpose of this study is to determine how the water tank affects the behavior of an apartment building when earthquake occurs. Dynamic analysis was accomplished on two cases - 1) water tank is considered 2) water tank is not considered - to understand how it affects the behavior of a high-rise apartment building. Structural design was accomplished to understand how the water tank and the peak acceleration affects each structural member. The effect of the water tank on the response of structure was large. Elsewhere the water tank has no effect on the design of a strutural member. However some structural members were affected when the peak acceleration of an earthquake is 0.4g.