• The Journal of Engineering Geology
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• v.19 no.2
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• pp.165-175
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• 2009

This study is concerned with creep characteristics of red shale in the Haman Formation by the single stage and multi stage loading tests. Creep constants in the Griggs's experiential equation, ${\epsilon}_t$= a+$b{\cdot}log$ t + $c{\cdot}t$, are determined by regression analysis on the total data obtained. The transition time between the primary and second creep means the time when the differential value of $b{\cdot}log$ t is equal to the differential value of $c{\cdot}t$. The correlation equation between loads (${\sigma}$%) and creep constants is deduced from the three times multi stage loading tests. Also a failure time under each loads is anticipated from creep constants and maximum strain at the failure.

• Journal of Korean Society of Steel Construction
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• v.20 no.2
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• pp.247-258
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• 2008

In this study, static loading tests were performed on H-beam specimens to assess the static behavior of H-beam prestressed with multi-stepwise thermal prestressing method (TPSM). The amount of induced thermal prestress and connection type were differentiated among the 400-mm-high and 6,000-mm-long H-beam specimens to evaluate their effect on the behavior of the beams. From the experimental results, it between the H-beam and the cover-plate increased in yielding load by 13~18%, whereas stiffness increased by 27~34%. In case of specimens with both bolting and welding connection, yie lding load increased by 18~29% and stiffness increased by 43~51%. Multi-stepwise initial stress distribution was also observed from the prestressed specimens, verifying the effectiveness of the multi-stepwise TPSM. By application of the multi-stepwise TPSM, a significant increase in yielding load and stiffness can be achieved, hence increasing sectional and prestressing efficiencies.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.3
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• pp.97-102
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• 2018

Conventional PSC I type girders were adversely affected by the self - weight of concrete, anchorage, prestressing. In order to overcome this problem, PSC girder was constructed with a hollow in the web and developed a hollow web PSC type I girder which is applicable to 50 - 70m span by multistage stressing and then actually long span hollow web PSC girder bridge was constructed. In this study, the results of Static Load Test and the Finite Element Analysis of the hollow web PSC I girder bridges were compared and analyzed, and the Load Carrying Capacity and safety of PSC girder bridges were evaluated. The Static Load Test and the numerical analysis results of this bridge showed similar tendency and the behavior of the hollow web PSC I girder was well simulated. The entire girders of the bridges had sufficient Load Carrying Capacity under the live load design condition and the bridges satisfied the safety and confirmed the appropriateness of the construction.