• Journal of the Korea Concrete Institute
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• v.23 no.5
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• pp.657-665
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• 2011

LB-DECK, a precast concrete panel type, is a permanent concrete deck form used as a formwork for cast-in-place concrete pouring at bridge construction site. LB-DECK consists of 60 mm thick concrete slab and 125 mm height Lattice-girders partly embedded in the concrete slab. These decks have been applied to the bridges, which girder spacings are short enough to resist longitudinal cracking caused by construction loads. This paper presents experimental research work conducted to evaluate the cracking load of LB-DECKs designed for long span bridge decks. Twenty four non-composite beams and four composite beams are fabricated considering three design variables of thickness of concrete slab, height of lattice-girder, and diameter of top-bar. Static loads controlled by displacements are applied to test beams to obtain cracking and ultimate loads. Vertical displacements at the center of beams, strains of top-bar, crack propagation in concrete slab, and final failure modes are carefully monitored. The obtained cracking loads are compared to the analytical results obtained by elastic analyses. Long-term analyses using age-adjusted effective modulus method (AEMM) are also conducted to investigate the effects of concrete shrinkage on the cracking loads. Based on the test results, the tensile strength and the design details of LB-DECKs are discussed to prevent longitudinal cracking of long span bridge decks.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.985-988
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• 2008

Maglev is a system that a train runs levitated above a rail. Therefore it is very important to maintain a constant levitation gap for achieving serviceability and ride comfort. This study is a cooperation research subject of the 3-1 subject, performance improvement of maglev track structures, of the Center for Urban Maglev Program in Korea, started in 2006. The aim of this study is development of rapid constructions of bridge superstructure for maglev. At present, precast deck is widely used because of its superiority to cast-in-place concrete on quality and the term of works. The research group suggested basic systems of maglev guideway with PSC-U type and trapezoidal open steel box type girder, and precast deck, cooperating with Korea Railroad Research Institute, the managing institute of the 3-1 subject. In this study, full-scale structure was fabricated for structural safety evaluation of precast decks and rail, and a static performance test of those structures was performed.

• Journal of the Korea Concrete Institute
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• v.29 no.2
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• pp.159-167
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• 2017

A precast concrete deck system is considered an effective alternative in terms of its rapid construction and quality assurance than cast-in-place concrete deck. In precast concrete deck system, structural performance and serviceability are mostly determined by the connection methods between the precast decks. This research proposes more improved precast deck system with asymmetric ribbed connection details improving the disadvantage of previous precast deck system such as difficulties in assembling precast decks. And in this precast deck system, a separate form is not required at the site because partition wall of the precast decks serves as a form when placing non-shrinkage mortar in the connection part of the precast decks. Therefore, rapid construction is possible. Flexural performance is verified through load tests considering main parameter such as rib length in the precast deck connection. From the test results, it can be inferred that the development of the rebar and prevention of adhesion failure in the partition wall of the precast deck system are important factors in securing the flexural performance. Although the structural performance of the precast deck system with asymmetric connection details is gradually reduced as the rib length in the precast deck connection increases, the proposed precast deck system shows sufficient flexural performance and can be applied to the connection part of precast decks effectively.

• Magazine of the Korea Concrete Institute
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• v.20 no.2
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• pp.50-53
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• 2008

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.2
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• pp.116-124
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• 2011

To purpose of this study is to develop the new type of precast concrete baseplate which is only for bimodal tram. The experiments with real size specimens, which are hollowed precast baseplate, prove the efficacy of new designed baseplate by comparing with the result of RCAHEST. Through tests progressed according to different loading locations, the specimens show the stability by the safety factor of 8~9. Also the results of RCAHEST that is the nonlinear finite element method program, appropriately estimate the occuring crack on concrete, yielding reinforcement and ultimate behavior at failure.

• Magazine of the Korea Concrete Institute
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• v.10 no.6
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• pp.161-168
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• 1998

Increase of traffic volume in recent years results in deterioration of the bridge slab, which is directly subjected ot vehicle loads. Where extensive repair is necessary, replacement or enhancement of load carrying capacity using full depth precast concrete deck is often the most practical solution. Precast deck system has transverse joints between adjacent precast decks. Vertical shear forces occur when a vehicle wheel load is carried by precast decks and the joints are used to transfer the load to an adjacent deck. Effective load transfer between precast decks is critical for integral behavior. Finite element analysis and tests were run on the proposed femal-to-female type joint. 18 joint specimens were tested to investigate the effects of angle. D/H, and confining stress under static load. Results indicate joint with angle of 60$^{\circ}$ and D/H of 1/4 shows the improved load carrying capacity on crack. It is effective in protecting the cracking of joints to keep the joint in compression using confining stress.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.49-50
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• 2009

We developed a new FRP-concrete composite deck applied to cable-stayed bridges, and verified the feasibility of design concept for negative moment zone in case of composition between this deck system and girder.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.6
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• pp.196-205
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• 2017

In precast deck system, structural performance and serviceability are mostly determined by the connection methods between the precast decks. This study proposes precast deck system with asymmetric ribbed connection details using High Strength Fiber Reinforced Concrete(HSFRC) with filler. To verify the proposed method, the flexural performance experiment was carried out with variation of joint cross section type and splice rebar details. From the test results, regardless of joint details, spliced tensile rebars of specimens were deformed to yielding strain level. Also, all types of specimens resulted in sufficient flexural performance. These test results show that the minimum lap splice length specified in current Korea Highway Bridge Design Code is conservative for precast deck joint using HSFRC. Therefore, splice details can be simplified and joint width can be reduced by using HSFRC with filler between the precast decks, and the proposed precast deck systems can be applied to the connection part of precast decks effectively.

• Journal of the Korea Concrete Institute
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• v.25 no.5
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• pp.517-528
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• 2013

The modular technology has been already applied in automotive industry, plant and shipbuilding industry. Recently, the modular technology was applied in bridge construction. The modular bridge is different from the existing precast bridges in terms of standardized design that the detailed design of members is omitted by using the standard modules; the design of the modular bridge is completed by only assembling the standard modules without design in member level. The girder-type precast modular bridge has been developed as a simply supported bridge. The girder-type precast modular bridge could be applied to the multi-span bridges through the continuity method. The continuity of the girder-type precast modular bridge is achieved by using the link slab which is easy to construction and appropriate to the rapid construction. The link slabs have been used as the type of reinforced concrete structure in US from the 1950's. In 2000's, the link slab using the engineered cementitious concrete (ECC link slab) has been developed. In this study, the RC type link slab which is more reproducible and economic relative to the ECC link slab was used for the continuity of the girder-type precast modular bridges, and the construction detail of RC type link slab was modified. In addition, the modified iterative design method of RC type link slab was proposed in this study. To verify the proposed design method, the flexural tests were conducted using the RC type link slab specimens. Also, the fatigue test using the mock-up specimen was conducted with cyclic loading condition up to two million cycles.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2A
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• pp.149-159
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• 2010

This paper presents an experimental study on the structural behavior of composite CFT truss girder bridge with full depth precast panels. The length of span is 20,000 mm. The CFT truss girder is a tubular truss composed of chord members made of concrete-filled and hollow circular tubes. To determine fundamental structural characteristics such as the strength and deformation properties of composite CFT truss girder bridge, static and dynamic tests were conducted. The natural frequencies calculated by the FEM are in good agreement with experimental results obtained from dynamic test. Bracing have only a small effect on the natural frequencies of composite CFT truss girder bridge as indicated by the FEM results. The yield strength and deformation of the composite CFT truss girder bridges were investigated through a static bending test. Besides, the test results showed that uniform distribution of shear connectors can be applicable in composite CFT truss girder bridges.