• Title/Summary/Keyword: RC 슬래브 교량

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Correlation Analysis between Damage of Expansion Joints and Response of Deck in RC Slab Bridges (RC 슬래브교의 신축이음 손상과 바닥판 응답과의 상관관계 분석)

  • Jung, Hyun-Jin;An, Hyo-Joon;Park, Ki-Tae;Jung, Kyu-San;Kim, Yu-Hee;Lee, Jong-Han
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.25 no.6
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    • pp.245-253
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    • 2021
  • RC slab bridges account for the largest portion of deteriorated bridges in Korea. However, most RC slabs are not included in the first and second classes of bridges, which are subject to bridge safety management and maintenance. The highest damaged components in highway bridges are the subsidiary facilities including expansion joints and bearings. In particular, leakage through expansion joints causes deterioration and cracks of concrete and exposure of reinforced bars. Therefore, this study analyzed the effect of adhesion damage at expansion joints on the response of the deck in RC slab bridges. When the spacing between the expansion joints at both ends was closely adhered, cracks occurred in the concrete at both ends of the deck due to the resistance rigidity at the expansion joints. Based on the response results, the correlation analysis between displacements in the longitudinal direction of the expansion joint and concrete stress at both ends of the deck for each damage scenario was performed to investigate the effect of the occurrence of damage on the bridge behavior. When expansion joint devices at both sides were damaged, the correlation between displacement and stress showed a low correlation of 0.18 when the vehicles proceeded along all the lanes. Compared with those in the intact state, the deflections of the deck in the damaged case at both sides showed a low correlation of 0.34 to 0.53 while the vehicle passed and 0.17 to 0.43 after the vehicle passed. This means that the occurrence of cracks in the ends of concrete changed the behavior of the deck. Therefore, data-deriven damage detection could be developed to manage the damage to expansion joints that cause damage and deterioration of the deck.

An Experimental Study on the Structural Bechavior of Two-layered Reinforced Concrete Slabs in Bridges (교량에서 2층 분리타설한 철근콘크리트 슬래브의 구조거동에 관한 실험연구)

  • 오병환;이형준;이명규;한승환
    • Magazine of the Korea Concrete Institute
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    • v.6 no.3
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    • pp.162-172
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    • 1994
  • The flexural and horizontal shear behavior of overlaid concrete slabs with polymer interface is investigated in the present study. An experimental program was set up and several series of overlaid concrete slabs have been tested to study the effect of different surface preparations and dowel bars between old slab and overlay under service and ultimate loads. 'The cracking and ulti mate load behavior for various cases including acryl emulsion treatment and doweled joints has been studied. The present study indica.tes that the overlaid concrete slabs behave integrally with existing bottom slabs up to ultimate range for rough and doweled joints with polymer interface. The pres ent study provides a firm base for the realistic design of two-layered RC slabs in bridges.

An Experimental Study on Half Scale RC Slab Bridges Strengthened with Carbon Fiber Sheet (CFS로 보강된 모형 RC 슬래브 교량의 실험적 연구)

  • 심종성;김규선;김경민
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.04a
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    • pp.537-542
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    • 1999
  • The design methodologies for carbon fiber sheet(CFS) strengthening of RC structures are not well established yet because the structural behavior of strengthened RC structures is more complex than that of unstrengthened ones. Even though the research for the methods using CFS has beed studied, the strengthening effects and structural behaviors of strengthened structures are not systematized yet. The purpose of this study is to carry out the experimental studies on three kinds of half scale RC slab bridges and to investigate the behavior of RC slab bridges from the experimental results. Typical flexural failure occurs in the non-strengthening slab like general RC slab bridges, and also the flexural failure occurs in the all area strengthened slab with sudden rip-off failure of strengthening material by punching shear. For the case of strip type strengthened slab, flexural failure occurs, with rip-off of second strip at the base of loading point. Strengthening effect on the slab using CFS is that the strength is increased upto 7~15 percent and the crack pattern is changed.

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An Experimental Study on Strengthening Performance of RC Slab used of Surface Bonded Method of GSP and CFRP Sheet (GSP와 CFRP 쉬트의 표면부착공법을 이용한 RC 슬래브의 보강성능 평가에 관한 실험적 연구)

  • Ahn, Ki-Man;Kim, Kwang-Soo;Park, Sun-Kyu;Lee, Young-Jae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.6
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    • pp.95-102
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    • 2007
  • Recently, an improved capacity for RC bridges is required by their deterioration or necessary to carry traffic increase. Strengthening is known as a better way to improve capacity of bridges than reconstructing in terms of economy. The surface bonded method, which is normally used with FRP material, has some advantages related to conveninent application and time-save among other strengthening methods. FRP material is light and has high tensile strength compared to steel. Therefore, this paper presents how structural capacity strengthed with CFRP sheet and Glass fiber-Steel Plate (GSP) is improved.

Spectra of Road Surface Roughness on Bridges of Minor Road (지방도 도로교 노면조도의 스펙트럼)

  • Chung, Tae Ju;Cha, Bong Ki
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.36 no.5
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    • pp.757-767
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    • 2016
  • The power spectral density (PSD) for the road surface roughness on the bridges of minor roads in Wonju city and Hoengseong-gun, Gangwon-do is presented. To obtain the PSD, the road surface roughness on 18 different bridges with various superstructure type and span is measured by GPS at every 10 to 30cm interval. Assuming the PSD as the stationary normal probability process with zero mean value, the PSD of measured road surface roughness is obtained by applying the Maximum Entropy Method (MEM). A simple formula in evaluating the PSD of RC slab bridge, Rahmen bridge and PSC I-girder bridge which is applicable to the dynamic response analysis of bridges considering the road surface roughness is proposed. Using the calculated PSD curves, the road surface conditions on the 18 bridges are evaluated. The statistical relationship between the PSD and the IRI is presented by applying linear regression and correlation analysis.

Seismic Fragility Analysis of Concrete Bridges Considering the Lap Splices of T-type Column (T형 교각의 겹침이음을 고려한 콘크리트 교량의 지진취약도 분석)

  • An, Hyojoon;Cho, Baiksoon;Park, Ju-Hyun;Lee, Jong-Han
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.43 no.3
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    • pp.287-295
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    • 2023
  • The collapse of bridges due to earthquakes results in many casualties and property damages. Thus, accurate prediction and preparation are required for the behavior of bridges during earthquakes. In particular, columns play an important role in the seismic behavior of bridges. The risk of collapse due to an earthquake increases when there is a problem of the insufficient lap splice in the column. In this study, to analyze the characteristics of the lap splice in the column, a numerical model was defined for the insufficient lap-spliced columns and verified using experimental data. The developed column model was applied to a commonly used RC slab bridge. Nonlinear static analysis for the column was performed to evaluate the change in the performance of the column according to the lap-spliced length. In addition, this study assessed the effect of the lap-spliced length on the seismic fragility analysis.

A study on the Life Cycle Profiles(LCP) for RC Slab Bridge (철근콘크리트 슬래브교의 노후화 예측모델에 관한 연구)

  • Ahn, Young-Ki;Lee, Chae-Gue;Lee, Jin-Wan
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.7 no.3
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    • pp.251-262
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    • 2003
  • LCP(Life Cycle Profiles) of bridge structures are indispensable for the LCC(Life Cycle Cost) evaluations of bridge system. The bridge under considerations may be newly-designed one or one in service. Thus, a systematic study of LCP is essential for both reliable LCC evaluation and strategic bridge management. LCP is mainly influenced by the structural environment in nature. However, in Korea, LCC evaluation has been performed with the LCP of foreign research results or only with the pieces of professional engineers' opinion. Therefore, to alleviate the drawbacks of foreign LCP and to enhance the reliability of current LCP, LCP should be established using the available data in bridge management system(BMS). In this study, LCP along with a subset of the BMS data was investigated and several mathematical expressions were proposed and evaluated. The condition ratings of a bridge were trasformed into the numerical indices through fuzzy logics with real field data. From the numerical results, it is concluded that the mathematical LCP model of $y=\sqrt{y^2_0-at}$ is shown to be the fittest one (R=0.815) to express the condition rating varied with the age. This has been drawn from the case study of slab bridges under the similar conditions.

Investigation of Sectional Force on Increasing of Dead Load with Bridge Deck Overlay using Electric Arc Furnace Slag Sand (전기로(電氣爐) 산화(酸化)슬래그 잔골재를 이용한 교면포장(橋面鋪裝) 시 단위질량(單位質量) 증대(增大)에 따른 슬래브 단면력(斷面力) 검토(檢討))

  • Jung, Won-Kyong;Chon, Beom Jun;Gil, Yong-Soo
    • Resources Recycling
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    • v.22 no.2
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    • pp.62-70
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    • 2013
  • Electric arc furnace slag is made in ironworks during steel refining, it is been increasing chemical and physical resistibility using ageing method of unstable state of melting steel slag for using concrete's fine aggregates. Which is been changing stable molecular structure of aggregates, it restrains moving of ion and molecule. In Korea, KS F 4571 has been prepared for using the electric arc furnace slag to concrete aggregates. In this study, Electric arc furnace slag is used in the PMC(Polymer Modified Concrete) which is applied a bridge pavement of rehabilitation, largely. In that case, this study evaluates the structural safety about increasing the specific weight. The 4-type bridges(RC slab bridge, RC rigid-frame bridge, PSC Beam bridge, Steel box girder bridge) pavement's increasing the total dead load is in 1 ~ 2%. Design moments in a load combination are increased less then 2%. safety factor is decreased less than 3%. Therefore, the structural safety has no problem for applying the electric arc furnace slag within PMC in bridge.

A Study on Improvement of Maintenance Strategy based on Analysis of Bridge Safety Grade (교량 안전등급 분석을 통한 유지관리전략 개선 방안 연구)

  • Hwang, Yoon-Koog;Sun, Jong-Wan;Choi, Young-Min;Park, Kyung-Hoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.3
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    • pp.36-43
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    • 2021
  • Because bridges are major national infrastructure, regular safety inspections or diagnoses for bridges have been conducted in accordance with the "Special Act on the Safety and Maintenance of Facilities." Accordingly, the condition and safety assessments of the bridge are conducted to derive the condition and safety rating, respectively. A lower result is determined to be the safety grade of the bridge. In this study, the relationship between the condition rating and safety rating, which are the core of the bridge safety grade, was analyzed by the representative superstructure types of bridges, such as RC slab, PSCI girder, Steel box girder, Rhamen, and Preflex girder, to identify the correlation status and range between each rating. A reasonable improvement direction for establishing existing maintenance policies was suggested by proposing an alternative plan to change the proper implementation cycle of the inspection and diagnosis of bridge superstructure types. As a result of the research, it is necessary to adjust the inspection and diagnosis cycle according to the superstructure type and safety grade. In addition, maintenance policies need to be improved through detailed research on more diverse bridge types in the future.

Shear Strength Prediction of FRP RC Baem without Shear Reinforcements (전단 보강이 없는 FRP RC보의 전단강도 예측)

  • Lee, Jae-Hoon;Shin, Sung-Jin
    • Journal of the Korea Concrete Institute
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    • v.22 no.3
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    • pp.313-324
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    • 2010
  • There are many problems in application of FRP reinforcing bars as shear reinforcement, since bending of FRP bars is not a feasible process on construction site. Even though FRP bars can be manufactured in bent shape, they have lower strength at bent location. However, there are no serious problems to use FRP bars as flexural reinforcement. Plates or slabs like bridge decks, in general, do not need shear reinforcements. These types of members with FRP flexural reinforcement have lower shear strength than those with conventional steel flexural reinforcement. However, reliable process or equation for shear strength estimation of FRP reinforced concrete without shear reinforcement are not established, yet. In this study, predicted shear strength obtained from available design equations and assessment equations are compared with 211 experimental results. The results showed that among the current design codes, the Architectural Institute of Japan (AIJ) and the Institution of Structural Engineers (ISE) provided the best estimation. ACI 440.1R-06 provided conservative results with degree of dispersion similar to that of ISE. In addition, regression analysis on the collected experimental results was conducted to develop regression models. As a result, a new reliable shear strength equation was proposed.