• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1991.04a
• /
• pp.34-42
• /
• 1991

This study is directed for the development of an efficient system-level Importance Sampling Technique for system reliability analysis of bridge structures Many methods have been proposed for structural reliability assessment purposes, such as the First-order Second-Moment Method, the Advanced Second-Moment Method, Computer Simulation, etc. The Importance Sampling Technique can be employed to obtain accurate estimates of the required probability with reasonable computation effort. Based on the observation and the results of application, it nay be concluded that Importance Sampling Method is a very effective tool for the system reliability analysis.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1990.10a
• /
• pp.105-110
• /
• 1990

Effective maintenance system for national highway bridges has been requested due to increasing numbers of bridges. In this study, bridge data base is established in accordance with rating criteria for the structural conditions and functions of bridges. Maintenance system using PC-80386 hardware and ORACLE software is developed to rank the priority of either reconstruction or repairing of bridges and to provide with those information to bridge maintenance staff in order to perform bridge maintenance effectively. With this pre-establised data base and computerized maintenance system, data and information for planning of bridge construction could be obtained in times.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1992.10a
• /
• pp.112-120
• /
• 1992

The use of Pre-processor for building structural analysis used to rely upon filling up fixed format data, which was ineffective and error-prone. This research attempts to integrate structural analysis system with DBMS and CAD system in order to make it easy to exchange data between pre-process, analysis, and post-process stages. Automatic generation of database from pre-process stage allows easy preparation of main input data for other structural analysis programs. CAD system with some sub-programs written in LISP and C works as a graphic user interface. This approach gives an easy, effective and error-free way of inputing data for structural analysis.

• Journal of the Korean housing association
• /
• v.15 no.4
• /
• pp.107-115
• /
• 2004

The purpose of this paper is to study on the architectural value in Dom-Ino system. Dom-Ino system by Le Corbusier is a structural system for effective production in terms of physical reproductivity and a modeling system from the view of formal composition. It creates planar grid with a fixed ratio, manipulates the user group, and becomes the basic construction method. Form comes out of geometrical proportion system, and grid-based plan provides regularity and order to elevation planning. Production requires standardization. Indoor space is maintained by uniformed and integrated service facilities. Dom-Ino system was a transitional step of the Modulor system which was created by Le Corbusier in 1945 and composes of and equivalent proportional system. The fact that the numerical proportion system is the one of appropriate design methods implys a progressive concept that architectural configurations are controlled by the technology of that time. And also the system is one of the object type of Corbusier's housing architecture.

• International Journal of High-Rise Buildings
• /
• v.1 no.1
• /
• pp.29-36
• /
• 2012

The diagrid structural system is considered to be not only the best structural system for constructing free form structures, but also a very effective system in resisting lateral load. As a newly investigated structural system, its complicated node has not yet been completely investigated and minimal experimentation of manufacturing and constructing the system have been conducted. Therefore, the constructing cost of the diagrid structural system is still comparatively high. In this paper, the cyclic performance of a diagrid node with an H-section brace will be discussed. Design details that consider productivity were proposed and their structural performances were assessed through experimental and analytical investigation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1997.10a
• /
• pp.160-165
• /
• 1997

Structural boundary condition is very important as a part of a structural system because it determines the dynamic characteristics of the structure. It is often to experience that experimental measurements of structural dynamic characteristics are somewhat different from the analytical predictions in which idealized boundary conditions are usually assumed. However, real structural boundary conditions are not so ideal; not perfectly clamped, for instance. Thus this paper introduces a new method to determine the non-ideal structural boundary conditions in the frequency domain. In this method, structural boundary conditions are modeled by both extensional (vertical) and torsional elastic springs. The effective springs are then determined from experimental FRFs (frequency response functions) by using the spectral element method (SEM). For a cantilevered beam experiments are conducted to determine the real boundary conditions in terms of effective springs. Dynamic characteristics (analytically predicted) based on identified boundary conditions are found to be much closer to experimental measurements when compared with those based on ideal boundary conditions.

• Structural Engineering and Mechanics
• /
• v.45 no.5
• /
• pp.655-676
• /
• 2013

In this study, strength reduction factors and inelastic displacement ratios are investigated for SDOF systems with period range of 0.1-3.0 s considering soil structure interaction for earthquake motions recorded on soft soil. The effect of stiffness degradation on strength reduction factors and inelastic displacement ratios is investigated. The modified-Clough model is used to represent structures that exhibit significant stiffness degradation when subjected to reverse cyclic loading and the elastoplastic model is used to represent non-degrading structures. The effect of negative strain - hardening on the inelastic displacement and strength of structures is also investigated. Soil structure interacting systems are modeled and analyzed with effective period, effective damping and effective ductility values differing from fixed-base case. For inelastic time history analyses, Newmark method for step by step time integration was adapted in an in-house computer program. New equations are proposed for strength reduction factor and inelastic displacement ratio of interacting system as a function of structural period($\tilde{T}$, T) ductility (${\mu}$) and period lengthening ratio ($\tilde{T}$/T).

• Structural Engineering and Mechanics
• /
• v.51 no.3
• /
• pp.487-502
• /
• 2014

In buildings structures, the flexural stiffness reduction of beams and columns due to concrete cracking plays an important role in the nonlinear load-deformation response of reinforced concrete structures under service loads. Most Seismic Design Codes do not precise effective stiffness to be used in seismic analysis for structures of reinforced concrete elements, therefore uncracked section properties are usually considered in computing structural stiffness. But, uncracked stiffness will never be fully recovered during or after seismic response. In the present study, the effect of concrete cracking on the lateral response of structure has been taken into account. Totally 120 cases of 3 Dimensional Dynamic Analysis which considers the real and accidental torsional effects are performed using ETABS to determine the effective structural system across the height, which ensures the performance and the economic dimensions that achieve the saving in concrete and steel amounts thus achieve lower cost. The result findings exhibits that the dual system was the most efficient lateral load resisting system based on deflection criterion, as they yielded the least values of lateral displacements and inter-storey drifts. The shear wall system was the most economical lateral load resisting compared to moment resisting frame and dual system but they yielded the large values of lateral displacements in top storeys. Wall systems executes tremendous stiffness at the lower levels of the building, while moment frames typically restrain considerable deformations and provide significant energy dissipation under inelastic deformations at the upper levels. Cracking found to be more impact over moment resisting frames compared to the Shear wall systems. The behavior of various lateral load resisting systems with respect to time period, mode shapes, storey drift etc. are discussed in detail.

• Wind and Structures
• /
• v.20 no.2
• /
• pp.315-326
• /
• 2015

To overcome the drawbacks of the traditional contact-type sensor for structural displacement measurement, the vision-based technology with the aid of the digital image processing algorithm has received increasing concerns from the community of structural health monitoring (SHM). The advanced vision-based system has been widely used to measure the structural displacement of civil engineering structures due to its overwhelming merits of non-contact, long-distance, and high-resolution. However, seldom currently-available vision-based systems are capable of realizing the synchronous structural displacement measurement for multiple points on the investigated structure. In this paper, the method for vision-based multi-point structural displacement measurement is presented. A series of moving loading experiments on a scale arch bridge model are carried out to validate the accuracy and reliability of the vision-based system for multi-point structural displacement measurement. The structural displacements of five points on the bridge deck are measured by the vision-based system and compared with those obtained by the linear variable differential transformer (LVDT). The comparative study demonstrates that the vision-based system is deemed to be an effective and reliable means for multi-point structural displacement measurement.

• International Journal of High-Rise Buildings
• /
• v.4 no.1
• /
• pp.39-44
• /
• 2015

This paper presents the structural health monitoring (SHM) of Shanghai Tower. In order to provide useful information for safety evaluation and regular maintenance under construction and in-service condition, a comprehensive structural health monitoring (SHM) system is installed in Shanghai Tower, which is composed of a main monitoring station and eleven substations. Structural responses at different construction stages are measured using this SHM system and presented in this study. Meanwhile, a detailed finite element model (FEM) is created and comparison of results between SHM and FEM is carried out. Results indicate that the time-dependent property of concrete creep is of great importance to structural response and the measured data can be used in FEM updating to obtain more accurate FEM models at different construction stages. Therefore, installation of structural health monitoring system in super-tall buildings could be considered as an effective way to assure structural safety during the construction process.