• Steel and Composite Structures
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• v.26 no.2
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• pp.227-239
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• 2018

Integral abutment bridges (IABs) have no joint across the length of bridge and are therefore also known as jointless bridges. IABs have many advantages, such as structural integrity, efficiency, and stability. More importantly, IABs have proven to be have both low maintenance and construction costs. However, due to the restraints at both ends of the girder due to the absence of a gap (joint), special design considerations are required. For example, while replacing the deck slabs to extend the service life of the IAB, the buckling strength of the steel girder without a deck slab could be much smaller than the case with deck slab in place. With no deck slab, the addition of thermal expansion in the steel girders generates passive earth pressure from the abutment and if the applied axial force is greater than the buckling strength of the steel girders, buckling failure can occur. In this study, numerical simulations were performed to estimate the buckling strength of typical steel girders in IABs. The effects of girder length, the width of flange and thickness of flange, imperfection due to fabrication and construction errors on the buckling strengths of multiple and single girders in IABs are studied. The effect of girder spacing, span length ratio (for a three span girder) and self-weight effects on the buckling strength are also studied. For estimation of the reaction force of the abutment generated by the passive earth pressure of the soil, BA 42/96 (2003), PennDOT DM4 (2015) and the LTI proposed equations (2009) were used and the results obtained are compared with the buckling strength of the steel girders. Using the selected design equations and the results obtained from the numerical analysis, equations for preventing the buckling failure of steel girders during deck replacement for maintenance are presented.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.4
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• pp.647-657
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• 2017

The main purpose of this study is to investigate the static & dynamic behavior of a precast bracket under precast road deck slab of double deck tunnel. In order to improve the construction speed, the field prefabricated bracket to connect the intermediate slab to the precast shield tunnel lining structure has been developed in the 'SPC (Steel Precast Concrete) bracket'. The experiments were performed for the full scale model in order to evaluate the performance of the 'SPC bracket', the structural stability was verified through the FEM analysis. The result of static loading test, no deformations or cracks of the bracket undergo the ultimate load was investigated. In addition, no pulling or deformation of the chemical anchor for fixing the bracket was measured. As a result of dynamic loading test, it was investigated that there is no problem in the chemical anchor for fixing the bracket. FEM analysis showed similar behavior to static load test and it was determined that there is no problem in serviceability and structural safety.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.129-138
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• 2006

Composite deck plate using a pre-assembled re-bar truss for slab with corrugated zinc galvanized sheet iron at manufactory, is given the improvement on design, manufacture, and performance for construction work of cast-in-place reinforced concrete slab by enabling to cast concrete directly without the form work. There are two methods in analyzing composite deck : Simplified 2D analysis and 3D analysis. Although simplified 2D analysis is being used up to date, the use of 3D analysis, allowing for the vierendeel behavior of composite deck by real configuration correlating to bar reducing, is demanded. To compare the simplified 2D analysis applied to allowable stress design with 3D analysis applied to limit state design, 8 specimen are manufactured. Main variables include the depth of slab, the length of span, the diameter of bottom bar and lattice bar, and the presence of corrugated zinc galvanized sheet iron. The comparison from the experimental result and analytical result indicates that applying of simplified 2D analysis is possible for the use of D10 with bottom bar. However, it is more reasonable to apply 3D analysis which allows to indicate vierendeel behavior considered the real configuration.

• Composites Research
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• v.26 no.2
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• pp.135-140
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• 2013

The static test was performed to verify the effect of the joint in the UHPC bridge deck slab and the minimum lap-spliced length was presented. A total of six test members was fabricated to estimate the static behavior of the steam curing UHPC bridge deck slab joint by the four points bending test method. The lap-spliced joint type was expected to be not only simple but also efficient in UHPC structure because of the high bond stress of UHPC. Test results show that the decrease of maximum flexural strength was about 30% and the minimum lap-spliced length which behaved similar to the continued reinforcement in strength and ductility was 150 mm.

• Structural Engineering and Mechanics
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• v.56 no.2
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• pp.241-256
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• 2015

Channel girder bridges that consist of a deck slab and two side beams are good choices for railway bridges and urban rail transit bridges when the vertical clearance beneath the bridge is restricted. In this study, the behavior of simply supported channel girder bridges was theoretical studied based on the theory of elasticity. The accuracy of the theoretical solutions was verified by the finite element analysis. The global bending of the channel girder and the local bending of the deck slab are two contributors to the deformations and stresses of the channel girder. Because of the shear lag effect, the maximum deflection due to the global bending could be amplified by 1.0 to 1.2 times, and the effective width of the deck slab for determining the global bending stresses can be as small as 0.7 of the actual width depending on the width-to-span ratio of the channel girder. The maximum deflection and transversal stress due to the local bending are obtained at the girder ends. For the channel girders with open section side beams, the side beam twist has a negligible effect on the deflections and stresses of the channel girder. Simplified equations were also developed for calculating the maximum deformations and stresses.

• Journal of Korean Association for Spatial Structures
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• v.21 no.3
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• pp.77-84
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• 2021

In this study, In order to apply the U-flanged truss hybrid beam to the actual construction site, the structural design of the basic module of the middle and low-rise neighborhood living facilities was performed according to the Korea Design Standard, and the construction cost and construction period were compared with the traditional reinforced concrete structure system. As a result of analyzing the construction cost for the basic module, if the U-flanged truss hybrid beam and D-Deck slab system are used, the construction cost can be reduced by 86% compared to the traditional reinforced concrete structure system. In addition, as a result of analyzing the construction period for a floor area of 1,000m², using the U-flanged truss hybrid beam and D-Deck slab system can save 2.0days in construction period compared to the traditional reinforced concrete structure system. Therefore, the U-flange truss hybrid beam can secure sufficient economic feasibility compared to the existing reinforced concrete method in terms of cost reduction and shortening of construction period.

• Journal of the Korean Society of Safety
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• v.23 no.5
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• pp.84-90
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• 2008

The occurrence of longitudinal cracking in concrete deck of box girder bridge is affected by many factors, but the most important factors are the shrinkage and thermal gradient of deck slabs. In this study, therefore, the tensile stresses at the bottom of deck were calculated from the experimental data(autogeneous shrinkage, drying shrinkage, and thermal gradient of deck slab). Also, the possibility of longitudinal cracks at bottom of deck was estimated. For this purpose, full-scale box girder segments have been fabricated and tested. The thermal gradients and shrinkage strains of deck slabs were measured after placement of concrete. Also, analytic program was conducted for the evaluation of longitudinal cracking in bridge deck considering differential shrinkage induced from non-uniform moisture distributions in concrete.

• Structural Engineering and Mechanics
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• v.75 no.1
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• pp.19-32
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• 2020

Due to repetitive traffic loadings and environmental attacks, reinforced concrete (RC) bridge deck slabs are suffering from severe degradation, which makes structural repairing an urgency. In this study, the fatigue performance of an RC bridge deck repairing technique using ultra-high performance fiber reinforcement concrete (UHPFRC) overlay is assessed experimentally with a wheel-type loading set-up as well as analytically based on finite element method (FEM) using a crack bridging degradation concept. In both approaches, an original RC slab is firstly preloaded to achieve a partly damaged RC slab which is then repaired with UHPFRC overlay and reloaded. The results indicate that the developed analytical method can predict the experimental fatigue behaviors including displacement evolutions and crack patterns reasonably well. In addition, as the shear stress in the concrete/UHPFRC interface stays relatively low over the calculations, this interface can be simply simulated as perfect. Moreover, superior to the experiments, the numerical method provides fatigue behaviors of not only the repaired but also the unrepaired RC slabs. Due to the high strengths and cracking resistance of UHPFRC, the repaired slab exhibited a decelerated deterioration rate and an extended fatigue life compared with the unrepaired slab. Therefore, the proposed repairing scheme can afford significant strengthen effects and act as a reference for future practices and engineering applications.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.363-366
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• 2005

When widening or repairing concrete deck slab, there is a joint inevitably. However, joining-construction method have following problem, that is the additional stress in existing part of bridge resulting from the specific process of joining-construction and the difference of amount of shrinkage between new and existing bridge. On this study, compared shrinkage stress of the direct joining construction method with the indirect joining construction method, and concluded the proper substitution rate of expansion cement. The rate of replacement was proper at $10\%$. but more than $15\%$, concrete had excessive expansion and weeker compressive strength. The time of placing closure concrete, considering the shinkage stresses and creep, was suitable in $45\~60$ days after placing the new concrete deck slab.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.77-80
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• 2004

In bridge deck systems, deflections and cracking can be controlled by longitudinal and transverse prestressing, There are some benefits, longitudinal cracking control, the thickness reduction of deck slab, the widening of deck width and the reduction of the cross section area, in transversely post-tensioned concrete box girder bridges. However, it has been not sufficient to study the structural behaviors of transversely post-tensioned concrete box girder. Therefore, It is needed to predict the structural behaviors by prestressing and static loading. In this study, the analytical and experimental load tests are carried out to study the effect of transverse prestressing on concrete box girder. For these objectives, four test specimens are fabricated with various tendon spacing and steel ratio of top slab. The analytical and experimental studies are performed to estimate effects of the prestressing and failure tests.