• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.420-420
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• 1999

• Journal of the Korea Construction Safety Engineering Association
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• v.2 no.4 s.6
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• pp.28-71
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• 1992

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.2
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• pp.49-58
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• 1990

A numerical procedure is developed to analyze the time-dependent deflections of prestressed concrete bridges constructed by the segmental cantilever method. The developed computer program accounts for the time-dependent properties of prestressed concrete materials due to the varying modulus of elasticity, creep and shrinkage of concrete and the stress relaxation of prestressing steel. It also accounts for the stiffness increase due to the presence of the steel reinforcements and the effects of the shear deformation of the prestressed concrete bridge girders. The program is applied to a multi-span continuous segmental prestressed concrete bridge to demonstrate its capabilities and to explore the behavior characteristics of the segmental bridges.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.5
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• pp.27-33
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• 2010

In this study, a monotonic loading test to estimate structural capacity of 12 meter long full scale precast pre-stressed concrete beam specimen was performed with a 2,000 kN dynamic actuator. A couple of embedded steel plate was installed at the ends of the beam and specimens were connected to steel girder frame with high tension bolts. Nominal compressive strength of pre-stressed concrete beam and slab were 50 MPa and 24 MPa respectively. Two HD25 tensile steel reinforcements were welded on vertical plate of embedded steel plate. Pre-stressed concrete beam specimen was loaded by displacement control method with a certain loading pattern which was repeated loading and unloading with 10mm increment displacement. About 88.34%, 86.97% and 66.83% of displacement restoration ratios were evaluated at elastic, inelastic and plastic behavior region of specimen respectively.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.3
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• pp.215-222
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• 2017

In order to evaluate a stress state of concrete according to the change of tensile force of prestressed beam, improved nonlinear resonant ultrasonic spectroscopy(NRUS) method is proposed. This technique is advantageous to evaluate the stress state in initial state because the method shows much higher sensitivity than existing linear ultrasonic methods. The NRUS technique measure a nonlinearity parameter, which is calculated from the resonant frequency shift of ultrasonic wave related to the medium state, and the result is also closely related to the stress state of concrete. In this study, the nonlinearity parameter was measured with the change of tensile force to verify the close relationship between the two factors, and the effect of repetitive load cycle on the change of nonlinearity parameter was analyzed. In addition, sensitivity comparison with the linear ultrasonic pulse velocity method was performed. Through the experimental results, the possibility of NRUS technique for the evaluation of stress state in prestressed beam was confirmed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.2
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• pp.133-140
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• 2018

A nonlinear finite element analysis was conducted in order to examine the moment capacity and flexural behaviour of hollow prestressed concrete filled steel tube(HCFT) piles which compose hollow PHC piles inside thin wall steel tubes. The parameters investigated in this study were various contact conditions between concrete and steel tube, thickness of concrete tube and various PC strands. A simple method is proposed to determine the ultimate flexural strength based on plastic stress distribution method. In order to verify the proposed method, calculated moment capacity of various HCFT piles are compared with the experiment and numerical analysis results.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.39-40
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• 2009

This study is for development the anchorage that for development and practicality a holed precast prestressed concrete girder for forming an I-type Prestressed concrete girder bridge, in which at least one hole is formed in a body portion of the I-type Prestressed concrete girder.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.4
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• pp.41-49
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• 1989

Following the previous paper, the results of test are further presented. As partially prestressed concrete members permit cracks under the service state, deflection and crack control of partially prestressed concrete members is more important than that of reinforced or fully prestressed concrete members. By the test results of load-deflection relation, it can be shown that prestressing ratio significantly affects the behavior of partially prestressed concrete beams. Deflection prediction formula of some codes are tried, and test results are compared with various fomulae of crack spacing and crack width.

• Journal of the Korea Concrete Institute
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• v.26 no.6
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• pp.741-749
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• 2014

Prestressed hollow-core (PHC) slabs are structurally-optimized lightweight precast floor members for long-span concrete structures, which are widely used in construction markets. In Korea, the PHC slabs have been often used with cast-in-place (CIP) topping concrete as a composite slab system. However, the PHC slab members produced by extrusion method use concrete having very low slump, and it is very difficult to make sufficient roughness on the surface as well as to provide shear connectors. In this study, a large number of push-off tests was conducted to evaluate interfacial shear strengths between PHC slabs and CIP topping concrete with the key variable of surface roughness. In addition, the horizontal shear strengths specified in the various design codes were evaluated by comparing to the test results that were collected from literature.

• Journal of Korean Society of Steel Construction
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• v.14 no.5 s.60
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• pp.593-602
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• 2002

A new type of bridge superstructures referred to as Steel-Confined Prestressed Concrete Girder (SCP Girder) was developed, which is composed of concrete, steel plate, and prestressing tendon. The girder may maximize structural advantages of these components; thus, long span bridges with low height girder may be constructed. For the effective design and fabrication of the gilder, the design software program was developed and the process of fabrication established. The experimental girder designed using the program was manufactured in actual size to confirm the fabric ability of the girder. Propriety of design, structural safety, and applicability of the gilder were verified through the load test.