• Journal of the Korea institute for structural maintenance and inspection
• /
• v.9 no.2
• /
• pp.103-112
• /
• 2005

This study examines the stability of Sungsu bridge which was issued nine years ago because of its collapse accident and now is on the progress of extension work in each construction stage by construction monitoring system. From this study, the measured value in each construction stage of anchorage truss and suspended truss shows the agreement with the analytical values up to 60~110 percents, and the elements' stresses emanating from the pre-loading stage, are also similar to the analytical value. Regarding these results, it is expected that each member has enough stiffness and the construction condition is satisfactory. In addition, it is expected that the transverse members and sway bracing bolts integrate completely the existing truss and new attached truss as a one body from the result of the vibration test to find out the integration rates.

• Magazine of the Korea Concrete Institute
• /
• v.10 no.1
• /
• pp.4-9
• /
• 1998

• Journal of the Korean Society of Hazard Mitigation
• /
• v.1 no.2 s.2
• /
• pp.103-114
• /
• 2001

As the results of comparison with several anchorage design methods of PSC box girder, stress superposition effect by the order of prestressing force can't be considered in the case of multi-anchorage design with existing design methods. In anchorage design by 3-D finite element analysis, estimation of stress concentration region and stress flow are correctly defined, but the estimation of sectional forces in anchorage is very complicated. In the case of anchorage design by strut-tie model method, the stress superposition effect can be considered and sectional forces in anchorage are easily calculated. Therefore, strut-tie model method is remarkably suitable to anchorage design if geometrical conditions of the truss members are carefully considered.

• Magazine of the Korea Concrete Institute
• /
• v.18 no.1 s.90
• /
• pp.75-80
• /
• 2006

• Journal of the Korea Concrete Institute
• /
• v.21 no.6
• /
• pp.697-703
• /
• 2009

High-strength concrete corbels with varying percentage of steel fibers and two different anchorage types (welding to transverse bar, headed) for the main tension tie were constructed and tested. The results showed that performance in terms of load carrying capacities, stiffness, ductility, and crack width was improved, as the percentage of steel fibers was increased. In addition, the corbel specimens in which headed bars were used as the main tension tie reinforcements showed superior load carrying capacities, stiffness, and ductility compared to the corbel specimens in which the main tension ties were anchored by welding to the transverse bars. From the test results, it is expected that load carrying capacities, durability, and constructibility of high strength concrete corbels would be improved by using steel fibers and headed bars. Experimental results presented in this paper were also compared with various prediction models proposed by researchers and presented in codes. The truss model proposed by Fattuhi provides fairly good predictions for fiber reinforced high-strength concrete corbels.

• Journal of the Korea Concrete Institute
• /
• v.20 no.6
• /
• pp.747-754
• /
• 2008

In this study, high strength concrete corbels reinforced with steel fibers and polypropylene fibers, and subjected to the vertical and horizontal loads were constructed and tested. The results showed that performance in terms of load carrying capacities, stiffness, ductility, crack width, and number of cracks was improved, as the steel fibers and polypropylene fibers were added. The polypropylene fiber reinforced concrete corbels resulted in higher ductility in presence of horizontal loads, but showed larger crack width than the steel fiber reinforced concrete corbels. And, the heads of the headed bars provided excellent end anchorage of the main tension tie reinforcement. Experimental results presented in this paper are also compared with various prediction models proposed by codes and researchers. The refined strut-and-tie model showed more accurate and conservative predictions in presence of horizontal loads, and the truss model proposed by Fattuhi provides fairly good predictions for fiber reinforced concrete corbels.

• Journal of Korean Society of Steel Construction
• /
• v.20 no.5
• /
• pp.609-616
• /
• 2008

Recently, many ocean bridges that connect land to island or island to island have been constructed along with the improvement of the nation's economy. Long-span bridges can be categorized as suspension bridge, cable-stayed bridge, arch bridge and truss bridge. In this study, correction with respect to construction error can be presented on site through the monitoring of the cable tension change of real structure for four major construction stages so that construction accuracy, including the management of profiles, can be improved. A vibration method, the so-called indirect method that uses the cable's natural frequency changes from the acceleration sensor installed on the cable, is applied in measuring cable tension. In this study, the estimation formula for the effective length of cable with damper is presented by comparing and analyzing between actual measurement and analysis result for the change of the cable's effective length. By the way, it is known that the reliability of estimating cable tension by applying the former method that uses the net distance from damper to anchorage is low. Therefore, for future reference of the maintenance stage, the presented formula for estimating the effective length of cable can be used as a reference for the rational decision-making, such as the re-tensioning and replacement of cable.