• Wind and Structures
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• v.19 no.6
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• pp.649-663
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• 2014

The present paper discusses the characteristics of unsteady aerodynamic forces on long-span curved roofs. A forced vibration test is carried out in a wind tunnel to investigate the effects of wind speed, vibration amplitude, reduced frequency of vibration and rise/span ratio of the roof on the unsteady aerodynamic forces. Because the range of parameters tested in the wind tunnel experiment is limited, a CFD simulation is also made for evaluating the characteristics of unsteady aerodynamic forces on the vibrating roof over a wider range of parameters. Special attention is paid to the effect of reduced frequency of vibration. Based on the results of the wind tunnel experiment and CFD simulation, the influence of the unsteady aerodynamic forces on the dynamic response of a full-scale long-span curved roof is investigated on the basis of the spectral analysis.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.13-16
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• 2010

This study is an Investigation on the Watertightness Properties of Rain-Block System on the Sliding-Roof Joint of Large-Span Membrane Structures. In this experimental, we test the watertightness performance of joint part of sliding door in roof of large span membrane structure(for pilot project) under environment of rain and wind. A shape of rain water blocking systems of joint part in sliding door verifies the defects and effects of water leakage prevention in precipitation with the wind conditions. For obtaining watertightness of large span membrane structures, it is necessary quality of joints and performance, and quality of membrane material of a retractable roof as well as a closed roof. Also, for obtaining quality in joints, it is essential to make a watertightness guideline for design of large-span membrane.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.12
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• pp.1103-1110
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• 2013

Based on the string, Euler beam, and Timoshenko beam theories, the transfer functions of axially translating web system to predict the lateral tracking are introduced in this paper. In addition, total transfer function of a multi-span web handling system is developed by the combination of the transfer functions of each single span. Experiments and computations are carried out and the results obtained for the Timoshenko beam model are compared with those of other models. The comparison indicates that the predictions from the Timoshenko and Euler beam models are quite different from that of the classical string model in both the gain and phase response. The results are expected to help in the development of high fidelity models of web tracking systems within a general computational framework.

• Advances in concrete construction
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• v.4 no.3
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• pp.173-194
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• 2016

This paper consists in a study of a new contructive sequence of road viaducts with Movable Scaffolding System (MSS) using numerical tools based on finite element method (FEM). Traditional and new sequences are being used in Spain to build viaducts with MSS. The new sequence permits an easier construction of one span per week but implies some other issues related to the need of two prestressing stages per span. In order to improve the efficiency of the new sequence by reducing the number of prestressing stages per span, two solutions are suggested in this study. Results show that the best solution is to introduce the 100% of the prestressing force at the self-supporting core in order to improve the road viaduct construction with movable scaffolding system by reducing execution time without increasing economic costs.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.427-439
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• 2003

A previous study evaluated the seismic response of typical multi-span simply supported (MSSS) and multi-span continuous (MSC) steel-girder bridges in the central and southeastern United States. The results showed that the bridges were vulnerable to damage resulting from impact between decks, and large ductility demands on nonductile columns. Furthermore, fixed and expansion bearings were likely to fail during strong ground motion. In this paper, several retrofit measures to improve the seismic performance of typical multi-span simply supported and multi-span continuous steel girder bridges are evaluated, including the use of elastomeric bearings, lead-rubber bearings, and restrainer cables. It is determined that lead-rubber bearings are the most effective retrofit measure for reducing the seismic vulnerability of typical bridges. While isolation provided by elastomeric bearings limits the forces into the columns, the added flexibility results in pounding between decks in the MSSS steel-girder bridge. Restrainer cables, which are becoming a common retrofit measure, are only moderately effective in reducing the seismic vulnerability of MSSS and MSC steel girder bridges.

• Architectural research
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• v.19 no.4
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• pp.109-115
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• 2017

This study is done to evaluate how existence of shear-span ratio and shear reinforcing bar effects on shear performance from through shear experiment using PVA fiber reinforced ferroconcrete building. Ratio of shear-span was set 1, 1.7, and arrangement of shear reinforcing bar was set with KCI2012 regulation. In result, subject with less shear-span ratio, and shear reinforcing bar with arrangement of bar shows high stiffness. Subjects with high shear-span ratio show large difference depending on existence of shear reinforcing bar. Therefore, theoretical shear strength followed by CEB code underestimates experimental shear strength by 43.9%. Shear strength of the deep beam with headed bars is more affected by the bearing strength of head than the bond strength of bar.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.262-267
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• 2008

The type used mainly in present our country in the superstructure of the railway bridge including the high speed railway is classified by the box girder and the I-type girder, greatly. The box girder is mainly used by the high speed railway bridge, and the I-type girder is used mostly by general railway bridge style. In this study, according to current railway bridge design code, we execute design by the span length of each considered bridge form. Also we analyze the suitable girder height by the span length and calculate the construction costs. The comparative analysis of the structural efficiency is produced by the span length. From this study, it is exposed that the girder height by the span length is the biggest in box girder. Also it is evaluated that the construction costs of the box girder is higher than that of the I-type girder although there is a difference between more or less according to adopted construction method.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.193-200
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• 1998

The precast prestressed concrete girders of I-type section are frequently employed to design the short-to-medium span bridge. However, its beam depth is greatly increased as its span length is increased over than about 30m. Therefore, the economic and aesthetic effectiveness are rapidly decreased in case of the span length over 30m. The purpose of this paper is to verify the structural safety on the new spliced two span bridge and analyze the variation of member forces and stress distribution according to the construction stages and time. The new spliced technique is performed by partial post tensioning and release in the U-type girders. The structural characteristics of this technique is the introduction of secondary moment to reduce the bending moment by self weight of precast U-type girders constructed in simply supported beam type. So, it is expected that the structural efficiency of this spliced bridge may be improved more than other techniques.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.698-703
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• 2007

A simplified model which incorporates the moment-axial tension interaction of the double-span beams in a column-removed steel frame is presented in this paper. To this end, material and geometric nonlinear parametric finite element analyses were conducted for the double-span beams by changing the beam span to depth ratio and the beam size within some practical ranges. The beam span to depth ratio was shown to be the most influential factor governing the catenary action of the double-span beams. Based on the parametric analysis results, a simplified piecewise linear model which can reasonably describe the vertical, resisting force versus the beam chord rotation relationship was proposed. It was also shown that the proposed method can readily be used for the energy-based progressive collapse analysis of steel moment frames.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.99-106
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• 2002

This paper presents an analytical investigation on the behavior of simple span integral abutment bridge. An integral abutment bridge is a simple span or multiple span continuous deck type bridge having the deck integral with the abutment wall. Although the temperature variation and earth pressure are the major attributor to the total stress in integral abutment bridge, the superstructure has been designed by modeling it as a simple or continuous beam In order to investigate the effect of temperature change and earth pressure on the superstructure of integral bridge, the simple span integral bridge is modeled as a plane frame element. Performing frame analysis, the variations of bending moment and axial force of superstructure due to the various loading combination are investigated with respect to the flexural rigidity of piles, and the bending moment and axial force obtained by frame analysis are compared with the maximum bending moment obtained by conventional design method and initial prestressing force respectively.