• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.1
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• pp.239-249
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• 2003

The bridges, which were built between 20 and 30 years ago in rural area, have to support unexpected overload caused by excessive amount of transportation. For these rural bridges, repairs and replacements are needed. To avoid the high cost of rehabilitation, the bridge rating must correctly report the present load-carrying capacity. Rating engineers use Allowable Stress Design (ASD), Load Factor Design (LFD), and Load Resistance Factor Design (LRFD) to evaluate the bridge load carrying capacity. In this paper, the load rating methods are introduced, and it is illustrated how to use the load test data from literature survey. Load test is conducted to the bridge that was built 30 years ago in rural area. From load test results, new maintenance strategy is suggested instead of the bridge replacement.

• Structural Engineering and Mechanics
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• v.88 no.1
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• pp.95-107
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• 2023

In this study, circular thin-walled reinforced high strength concrete-filled steel tube (RHSCFST) stub columns with various tube thicknesses (i.e., 1.8, 2.5 and 3.0mm) and reinforcement ratios (i.e., 0, 1.6%, 2.4% and 3.2%) were fabricated to explore the influence of these factors on the axial compressive behavior of RHSCFST. The obtained test results show that the failure mode of RHSCFST transforms from outward buckling and tearing failure to drum failure with the increasing tube thickness. With the tube thickness and reinforcement ratio increased, the ultimate load-carrying capacity, compressive stiffness and ductility of columns increased, while the lateral strain in the stirrup decreased. Comparisons were also made between test results and the existing codes such as AIJ (2008), BS5400 (2005), ACI (2019) and EC4 (2010). It has been found that the existing codes provide conservative predictions for the ultimate load-carrying capacity of RHSCFST. Therefore, an accurate model for the prediction of the ultimate load-carrying capacity of circular thin-walled RHSCFST considering the steel reinforcement is developed, based on the obtained experimental results. It has been found that the model proposed in this study provides more accurate predictions of the ultimate load-carrying capacity than that from existing design codes.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.739-744
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• 2001

The concrete bridge deck is quitely required to be replaced or strengthened due to decreasing load carrying capacity. In this study, to increase load capacity of the reinforced concrete slab, bridge deck is reinforced with the glass fiber sheets. they are examined on the strengthen effect and the static behavior, This paper considers relation of load-displacement and strain-distance. The static behavior of the slab strengthened is represented to maximum load. Owing to that, they are examined on increasing load carrying capacity of reinforced bridge deck and strengthen effect about on the crack.

• Journal of Korean Society of Steel Construction
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• v.13 no.5
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• pp.477-492
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• 2001

About half of bridges in United States are considered to be deficient and therefore are in need of repair or replacement. Half of these are functionally obsolete, and others do not have required strength For these bridges repairs and replacements are needed To avoid the high cost of rehabilitation the bridge rating must corectly report the present load-carrying capacity Rating engineers use Allowable Stress Design(ASD) Load Factor Design(LFD), and Load Resistance Factor Design(LRFD) to evaluate the bridge load carrying capacity In this paper the load rating methods are introduced and bridge load test data are collected. The reasons that make the difference between test results and analytical results are explained for each bridge load test And load rating methods are applied to real bridge. The rating factors from each method are compared.

• Journal of the Korean Geotechnical Society
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• v.33 no.1
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• pp.67-77
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• 2017

In the present study, uplift load carrying behavior of micropiles with installation angle and pile spacing was investigated based on uplift load tests using single and group micropiles. In addition, evaluation methods of uplift load carrying capacity of group micropiles were proposed based on FHWA (2005) and Madhav (1987) and they were compared with test results to confirm the validity of proposed methods. From the test results, uplift load carrying capacities of single and group micropiles increased with the increase of the installation angle up to $30^{\circ}$, whose values also increased slightly with increasing pile spacing. For the proposed method based on FHWA (2005), the estimated values were similar to measured values up to $15^{\circ}$ of installation angle and 5D of pile spacing. For the proposed method based on Madhav (1987), on the other hand, it was observed that the estimated values were in good agreement with measured values in all installation conditions.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.2
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• pp.141-146
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• 1999

Recently, many existing bridges has been evaluated for maintenance and protection of collapse. In this study, field measurement according to truck loads tests on the reinforce concrete T beam bridge was carried out. Comparing the results of load test and structural analysis using the moments of inertia of gross section, crack section and effective section, and the moments of inertia of section considering depth of crack, it is conclude that the evaluation of load carrying capacity using the stress modification factor from structural analysis using the moments of inertia of gross section is more rational than using the other moments of inertia of sections.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.4
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• pp.485-492
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• 2007

In this study, based on the temperature distribution and the spalling histories those obtained in the companion paper, the thermal stress and moments of underground box structure were estimated. Additionally, the ultimate sectional moment considering with the thermal nonlinearities of material were estimated and the load carrying capacity of underground box structure was also obtained. As results, the load carrying capacity of negative moment part was dominated by thermal moment that come from thermal gradient of the section. However, the load carrying capacity of the positive moment part was rules by the yield stress of rebar that exposed to the high temperature induced spalling phenomena.

• Geomechanics and Engineering
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• v.10 no.5
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• pp.599-615
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• 2016

The present research presents experimental and finite element studies to investigate the behavior of piled raft-tunnel system in a sandy soil. In the experimental work, a small scale model was tested in a sand box with load applied vertically to the raft through a hydraulic jack. Five configurations of piles were tested in the laboratory. The effects of pile length (L), number of piles in the group and the clearance distance between pile tip and top of tunnel surface (H) on the load carrying capacity of the piled raft-tunnel system are investigated. The load sharing percent between piles and rafts are included in the load-settlement presentation. The experimental work on piled raft-tunnel system yielded that all piles in the group carry the same fraction of load. The load carrying capacity of the piled raft-tunnel model was increased with increasing (L) for variable (H) distances and decreased with increasing (H) for constant pile lengths. The total load carrying capacity of the piled raft-tunnel model decreases with decreasing number of piles in the group. The total load carrying capacity of the piles relative to the total applied load (piles share) increases with increasing (L) and the number of piles in the group. The increase in (L/H) ratio for variable (H) distance and number of piles leads to an increase in piles share. ANSYS finite element program is used to model and analyze the piled raft-tunnel system. A three dimensional analysis with elastoplastic soil model is carried out. The obtained results revealed that the finite element method and the experimental modeling are rationally agreed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.2
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• pp.107-120
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• 1987

This study is directed for the evolution of the rational approaches to the systematic evaluation of the load carrying capacity of bridges based on the practical and second moment reliability methods. A new approach for the evaluation of load carrying capacity of exsisting bridges is proposed in this study. The key idea behind this approach is in the fact that the load carrying capacity of an existing bridges under extreme traffic truck loadings may be measured by evaluating and classifying the reliability state of the bridge in terms of reliability index(${\beta}$). The rating formulas developed in this study are applied for the evaluation of load carrying capacity of the several actual deteriorated bridges inspected and tested for the capacity rating, and the results are compared with those calculated by using the current rating formulas. It may be concluded that the proposed rating formulas which is derived based on reliability methods, have to eventually replace the current rating formula when the basic statistical data for the resistance and load effects become available in the near future.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.6
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• pp.89-96
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• 2018

Bridge structures are a socially important infrastructure and safety management of bridges during the public service period is important. Steel box girder bridges, which account for a large percentage of road bridges, have been designed by allowable stress design method(ASD) and load carrying capacity have been evaluated using ASD. Although design specification has recently been changed to limit state design method(LSD), in most cases, ASD is still used for load carrying capacity evaluation. In this study, the two design methods were used to compare the results of a load rating factor evaluation on a number of bridges, and we are going to find out how to convert the existing rating factor by ASD into rating factor by LSD. The results of this study are expected to can be used as a basis for determining the need for reinforcement and evaluating load carrying capacity by LSD in bridge maintenance.