• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.1A
• /
• pp.237-246
• /
• 2006

In order to evaluate the seismic performance of damaged reinforced concrete members, particularly bridge piers, an inelastic time-dependent element is proposed. The proposed element enables increased characteristics due to structural intervention(i.e., repair or retrofitting) to be accurately reflected to the degraded strength and stiffness of the members. The inelastic time-dependent element having both birth and death time can freely be activated within the user-defined time intervals during static and dynamic time-history analysis. Comparative studies are carried out for reinforced concrete bridge piers that are repaired and retrofitted. Analytical predictions using the developed element show reasonable correlation with experimental results. Also conducted is a nonlinear time-history analysis of a reinforced concrete bridge under multiple earthquakes. The comparative analytical results prove the validation of current development. In all, it is concluded that the present element is capable of providing salient features for the healthy evaluation of seismic performance and hence seismic stability assessment of RC bridge piers being repaired and retrofitted.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.3 no.3
• /
• pp.1-8
• /
• 1999

The bridges for Korea High-Speed Railway(KHSR) under construction are supported with pot bearings on the middle pier and with pad bearings on the side piers, respectively. The dynamic analysis on these bridges due to trains with high speed, however, has been performed neglecting the effects of bearings. The objective of this study is investigation on the dynamic behavior of bridge supported by pad bearings. The effects of pad bearings with various flexibilities on the dynamic responses of bridges are studied. From the results of this study, the effects of elastomeric bearing on the dynamic responses of bridge(especially vertical accelerations) may cause undesirable behaviors.

• Journal of the Korean Geotechnical Society
• /
• v.20 no.3
• /
• pp.67-74
• /
• 2004

A case study was performed to verify the applicability of existing formulae for predicting bridge scour in cases where its piers are founded in fine-grained soils. The object of study was the Kanghwa Choji Bridge area where the streambed consists of mainly clayey soil. Site investigation included: direct measurement of scour depths around piers using an ultrasonic probe; and collection of undisturbed soil samples which were later used to determine geotechnical properties and scour rate under different stream velocities. Scour depth prediction was made by employing several conventional methods and compared with the measured value. All methods, not taking soil's intrinsic property against erosion into consideration, overestimated scour depth by a factor of 3.6 to 6.5. On the other hand, the SRICOS method yielded a reasonably acceptable overestimation by a factor of 1.7.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.1
• /
• pp.163-168
• /
• 2020

Since the industrialization in the 1960s, Korea has been expanding its transportation infrastructure, such as building bridges. Owing to bridge construction, studies on stability review have been carried out, and stability-securing technology has been developed. On the other hand, these were applied mainly to the upper part of the bridge, so applications to the lower part are limited. In particular, scour at the bridge pier causes erosion in the riverbed and bridge collapse. Hence, prevention studies and countermeasures are needed. In this study, an empirical formula was developed to evaluate the scour depth of a bridge, which was calculated through multiple linear regression analysis using the hydraulic model study data conducted in previous studies. The formula, which had a value of 0.91, was applied to the model test data that was not used for development to verify the developed formula. When the pier scour depths were compared in 23 cases, the error rate was less than 20% in 16 cases (70%). The empirical formula developed in this study is applicable to pier scour-depth calculations. Further research will be needed to develop a more accurate empirical formula for pier scour-depth calculations, and it is expected to reduce bridge damage caused by scour.

• 한국방재학회:학술대회논문집
• /
• 2010.02a
• /
• pp.41.2-41.2
• /
• 2010

하천, 해상 등에 위치한 교량 설계시 선박충돌을 방지하기 위해 교각 위치를 변화시킬 필요성이 발생한다. 이 때, 교각 위치에 따른 변단면을 갖는 PSC(Prestressed concrete) 박스거더의 형상 변화를 효과적으로 변경하기 위해 고려해야하는 구속조건을 추출하고 정의하였다. PSC 박스거더는 변단면 시공에 일반적으로 적용되는 FCM(Free cantilever method) 공법이 착용된 교량을 착용했으며, 구속조건 정의를 위해 설계지침서를 분석하여 구속조건으로 작용하는 매개변수를 추출하였다. 정의한 구속조건의 적용성을 검증하기 위해 파라메트릭 모델링을 수행하였으며, 그 결과로 생성된 모델에 대한 물량을 산출하여 대상교량에서 산출된 실제 물량과 비교 분석하였다.

• Journal of Korean Society of Disaster and Security
• /
• v.12 no.3
• /
• pp.51-57
• /
• 2019

In recent years, the occurrence of localized torrential rain has increased due to the increase in heavy rainfall and massive typhoons caused by abnormal weather. As a result, the flow rate of small and medium-sized rivers in Korea is rapidly increasing, affecting the safety of bridges and increasing the risk of scour. However, the domestic bridge construction technology does not reflect the watershed characteristics of domestic rivers because the bridge scour depth calculation formula developed overseas is used to calculate the bridge scour depth. Therefore, this study is a basic study for prevention of bridge damage according to scouring phenomenon, and a comparative analysis was performed between the experimental data measured through hydraulic model test and the scour depth formulas applied in Korea. In addition, the statistical analysis between experimental data and scour depth formula shows that Coleman's (1971) formula estimates the best scour depth. The results of this study are expected to be used to calculate more accurate bridge scour depth in river design and bridge design.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2010.05a
• /
• pp.129-130
• /
• 2010

Lap splice of longitudinal reinforcing steels was located in the plastic hinge region of most bridge piers that had been designed and constructed before the adoption of the 1992 seismic design provision of Korea Highway Design Specification. This research aims at improving the seismic performance of reinforced concrete bridge piers with lap-spliced longitudinal steels, of which the plastic hinge region was wrapped by the shape memory alloy (SMA) wires. Quasi-static test was used to investigate the seismic behaviours of RC test specimens.

• Journal of the Korea Concrete Institute
• /
• v.16 no.3 s.81
• /
• pp.357-367
• /
• 2004

In this paper, the effect of cumulative damage for reinforced concrete bridge piers subjected to both single and multiple earthquakes is investigated. For this purpose, selected are three set of accelerograms one of which represents the real successive input ground motions, recorded at the same station with three months time interval. The analytical predictions indicate that piers are in general subjected to a large number of inelastic cycles and increased ductility demand due to multiple earthquakes, and hence more damage in terms of stiffness degradation is expected to occur. In addition, displacement ductility demand demonstrates that inelastic seismic response of piers can significantly be affected by the applied input ground motion characteristics. Also evaluated is the effect of multiple earthquakes on the response with shear. Comparative studies between the cases with and without shear indicate that stiffness degradation and hence reduction in energy dissipation capacity of piers are pronounced due to the multiple earthquakes combined with shear. It is thus concluded that the effect of multiple earthquakes should be taken into account for the stability assessment of reinforced concrete bridge piers.

• Journal of Korean Society of Steel Construction
• /
• v.22 no.2
• /
• pp.161-171
• /
• 2010

Bridges have undergone distinctive development in accordance of the introduction of new materials and structural types. The importance on rapid construction technology is currently attracting more and more attention worldwidely as well as domestically because its effectiveness in reducing the overall construction cost. While a wide ranges of previous researches on rapid construction of super structures are available, the studies on substructures are quite limited. The development of the precast segmental internally confined hollow CFT piers are briefly introduced herein and design formulas are presented for pier segment joints, Also, a extensive parametric studies are carried out for the effect of the constitutive elements of the joints. Finally, the design formulas are verified throughout a series of extensive finite element analyses.

• Computational Structural Engineering
• /
• v.10 no.4
• /
• pp.30-33
• /
• 1997

차량의 제동에 의한 기존의 연구는 차량의 bounce와 pitch에 의한 차량의 거동특성에 따른 고려만이 이루어져 왔으며 교량의 수직방향 offset에 의한 고려는 이루어지지 않았다. 여기서 교량의 offset이란 교량의 주형과 상판 그리고 교좌부의 중심간에 수직방향 높이의 차이를 말하며, 차량의 제동이 발생할 때 이러한 offset에 의한 추가적인 휨거동이 발생하므로 이러한 offset을 고려하여야 한다. 아울러 고속철도와 같은 중차량의 경우에는 교각의 상대적인 강성에 의한 효과도 고려되어야 할 것이다.