• Journal of Korean Society of Steel Construction
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• v.18 no.5
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• pp.535-542
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• 2006

In this study, the effects of cross beams on the lateral distribution of live loads in composite rolled H-beam girder bridges, were investigated through three-dimensional finite element analysis. The parameters considered in this study were the inertial moment ratio between the main girder and the cross beam, the presence of the cross beam, and the number of cross beams. The live load lateral distribution factors were investigated through finite element analysis and the customary grid method. The results show that there was no difference between the bridge models with and without a cross beam. The cross beam of the beam and frame types also showed almost the same live load lateral distribution factors. However, the finite element analysis showed that the concrete slab deck plays a major role in the lateral distribution of a live load, and consequently, the effect of the cross beam is not so insignificant that it can be neglected.

• The Journal of the Korea Contents Association
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• v.11 no.1
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• pp.422-428
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• 2011

This paper presents results from the theoretical analysis of the lateral load distribution for a railway bridge designed with PSC girders which is one of most popular types of bridge in Korea. Typically, 3 sets of intermediate cross beams within a span have been installed for lateral load distribution. In this paper, the effect on the lateral load distribution by the number of intermediate cross beams were examined by both simple grillage analysis and finite element method. This study showed that at least, one set of cross beams at midspan should be needed to ensure the proper load distribution. However, the effect of cross beams on the load distribution becomes not significant though more than one set of cross beams are installed. Therefore, only one set of cross beans at midspan is recommended for constructibility and economic efficiency.

• 도로교통
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• s.76
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• pp.8-19
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• 1999

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.1
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• pp.9-14
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• 2008

In the case of horizontally curved bridges, the use of curved composite box girder bridges are increased due to its functionality and for aesthetical reason. As it compared with the open section, the steel box girder bridges have advantages to resistant of distortion and corrosion. In practice the grid analysis is conducted by utilizing only the cross beam. Since the stiffness of the concrete slab is not included in the grid analysis, the cross beam is induced the distribution of the live load. In this study the affects of the radius of curvature, the number of diaphragm and cross beam to the load distribution of the curved steel box girder bridge was investigated by applying the finite element method. The results indicate that the curvature of curved bridge had a large affect of the load distribution and as the curvature was increased the load distribution factor was increased. A single diaphragm at the center of girder is important role for the load distribution effects and structural stability, but additional diaphragm did not affect it as much. The affects of the cross beam to the load distribution were investigated and its influence was minor. It can be safely concluded that the addition of cross beam does not aid the purpose of the live load distribution. And the stiffness of concrete slab for the load distribution effects should be concerned in the design of curved steel box girder bridges.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.1
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• pp.39-58
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• 2004

It is very important that predict the inelastic seismic behavior exactly for seismic performance evaluation of a building in the performance based seismic design. Evaluation method of seismic performance based on the pushover analysis reflected in PBSE was developed by some researchers. For the evaluation of inelastic global and local seismic responses by pushover analysis exactly. lateral load distribution should be adjusted and reflected the dynamic characteristics of structural system and various seismic ground motions. And performance point should be determined based on the evaluation of reasonable deformation capacity of a building more exactly. An effective method based on the improved the adaptive lateral load distribution and the equivalent responses of a multistory building is proposed in this study to efficiently estimate the accurate inelastic seismic responses. The proposed method can be used to evaluate the seismic performance for the global inelastic behavior of a building and to accurately estimate its local inelastic seismic responses. In order to demonstrate the accuracy and validity of this method, inelastic seismic responses estimated by the proposed method are compared with those obtained from other analytical methods.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.4 s.56
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• pp.180-187
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• 2009

The objective of this research is to verify the code-specified girder distribution factors (GDF) for continuous steel girder bridges by field testing. Previous analytical study revealed that current GDF's specified in AASHTO Standard and AASHTO LRFD, developed for the simple span bridges are conservative even for the continuous bridges. In this study, field tests were performed for three continuous steel girder bridges to validate the GDF's specified in the AASHTO codes. The results show that the code values are conservative when compared with field tests, and in some cases, too conservative. Also, strains measured from the field test are, in most cases, smaller than those expected from the analytical results. However, when the GDF's from measured strains are compared with GDF's from analysis, it is found that the analysis results are not conservative, and in some instance, the analytical results underestimate the actual GDF's, which can lead to a groundless notion of safety. In one case, test results showed that the code GDF's specified in AASHTO LRFD is too permissive. As a result, it is found that GDF's specified in AASHTO LRFD should be used with careful reservation.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.4
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• pp.525-535
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• 1999

In this study, a new method of fabricated concrete deck bridge construction is proposed. This paper details the method in which concrete multi-girders and fabricated concrete decks are rested on the upper flange of the girder and the female to female type sheat-key is formed to connect girder and deck. The finite element analysis is performed to verify the accuracy of the structural behaviors of the fabricated concrete deck bridge by comparing with experimental results. The first task performed is the analysis of the equilibrium of the member force occurring between the deck and the girder. After verifying equilibrium of the member force determined by the finite element analysis, this process is applied to the analysis of maximum member force as the position of design load. This task is utilized to determine the safety of each member according to the same scale finite element model. The final process in this study is to compare the deflection of girders used in experiment with that of the same scale finite element model to verify the strength of fabricated cincrete deck bridge. By this comparison, it is shown that the behavior of the fabricated concrete deck bridge is almost same as the finite element analysis. The second task is to analyze the load distribution effect according to the number of diaphragms and the composite effect due to the cinnection of the deck and girder by the finite element analysis. From the results of second task, it is found that the load distribution effect is not related to the number of diaphragms in case of the central loading, but is related to the number of diaphragms for eccentric loading. Analysis of the load distribution indicates that the effective number of diaphragm is three. It is also shown that the maximum deflection is decreased to almost one half due to the composite action of the deck and girder.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.2
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• pp.131-138
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• 2015

In this paper, the modified live-load and designed formula are studied according to the fact the highway bridge design specifications are recently revised. The two examples for composite steel plates and PSC girder bridges are studied. The envelope is analyzed with the finite element models and lateral load distribution method applying the existing highway bridge specification(2010), the newly revised highway bridge specification(2015) and AASHTO LRFD. In case of composite steel plates, length changes between spans are studied, and in case of PSC girder. changes of the number of cross-beams and spans, and span-lengths, are analyzed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.3
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• pp.151-160
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• 2005

Current bridge design codes do not clearly specify the girder distribution factors for continuous bridges. The objective of the paper is to validate the use of code-specified girder distribution factors for the continuous steel girder bridges, and to provide a basis for recommended girder distribution factors (GDF) for interior girders, suitable for evaluation of existing continuous steel girder bridges. This paper presents the procedure and results of 3-dimensional finite element analysis that were performed on five of continuous steel girder bridges to verify girder distribution factors. The analysis results showed that the live load moment distribution at the negative moment region is very similar to those at the positive moment region in continuous steel girder bridges. It was also found that the GDF's based on the strain values are similar to those based on the deflection. GDF's based on the deflection show marginally better distribution. The analysis results confirmed that the code specified GDF's for continuous steel girder birdges are very conservative.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.236-243
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• 2005

Nonlinear static analysis is used to quantify the resistance of the structure to lateral deformation and to gauge the mode of deformation and intensity of local demands. A simple method for the nonlinear static analysis of complex building structures subjected to monotonically increasing horizontal loading(pushover analysis) is presented. The method is designed to be a part of new methodologies for the seismic design and evaluation of structures. A variety of existing pushover analysis procedures are currently being consolidated under programs such as ATC 40 and FEMA 273. And various techniques have been recommended, including the use of constant lateral force profiles and the use of adaptive and multimodal approaches. In this paper a modal pushover analysis using design response spectra of UBC 97 is proposed. Proposed method is compared against the method in FEMA 273 and ATC 40, and results of time history analysis.