교량용 외장재 적용에 따른 경관의 시각적 선호도 분석

박치성(Chi Seong Park),김신원(Shin Won Kim) 한국디자인문화학회 2011 한국디자인문화학회지 Vol.17 No.2

도시의 개발이 활발했던 초기 성장기에 건설된 교량들은 기능과 경제성에만 중점을 둔 합리적인 교량의 건설을 추구해온 것이 사실이며, 이러한 시대적인 배경 속에서 건설된 교량들의 대부분은 미(美)적인 배려가 상당히 미약한 수준이었다고 할 수 있다. 또한, 그 시절에 건설된 교량들은 오랫동안 외부환경에 지속적으로 노출되어 있었으므로 표면의 부식 및 오염 물질의 정착(定着) 등으로 인해 외형(外形)의 시각적 오염도가 높거나 물리적인 노후가 발생한 교량들이 대부분으로, 시간이 지남에 따라 교량의 외관은 점차 더 흉물스러운 경관으로 변해가고 있다. 위와 같은 문제들을 해결하기 위해 각 지자체들은 해당 지역의 경관개선사업을 실시하여, 노후 되어 성능이 저하된 교량들에 대한 철거 및 교체, 심미성이 부족한 교량의 경우, 리노베이션(renovation)사업 등을 실시하여 교량경관의 개선과 향상을 위한 노력을 기울이고 있는 실정이다. 이에 편승하여 교량용 외장재의 사용 빈도가 늘어나고 있으며 기설교량의 교량경관을 개선할 수 있는 효과적인 대안으로 주목받고 있다. 또한 신도시의 경관계획이나 지구단위의 특수구조물 경관설계 시에도 교량용 외장재가 사전에 반영되고 있어 신설교량의 조형성과 경관미의 향상을 목적으로 한 사용도 더욱 늘어날 것으로 보인다. 반면, 교량용 외장재에 관련된 기존의 문헌과 연구 자료들은 교량용 외장재에 대한 효용성 및 기능성에 관한 부분만을 언급한 자료가 대부분으로 미적 관점의 연구와 분석이 필요한 시점이다. 본 연구는 교량용 외장재를 설계에 반영하는 과정에서 참고할 수 있는 기초적인 정보와 자료를 제시하는 것에 목적이 있으며, 그 세부적 내용은 다음과 같다. 첫째, 교량용 외장재에 대한 문헌자료와 연구보고서 등을 통한 국내 및 일본 등의 현황을 파악하고 전반적인 기술적 고찰을 진행하였다. 둘째, 시각적·미적 평가를 수행하기 위해 대상지를 선정하고 해당 교량경관의 현황조사 및 분석을 진행하였다. 셋째, 경관 통제점을 바탕으로 시각적 평가를 위한 사진촬영을 진행하였다. 넷째, 형식미학적 관점의 평가지표를 도입하여 정량적 평가를 실시하였다. 다섯째, 교량별, 외장재 적용 유·무별, 외관의 재료별 선호도를 등을 분석하였다. 분석에는 SPSS. ver18을 사용하여 신뢰도분석, 집단별 t-test, one way-anova를 각각 실시하였다. 결론적으로 교량용 외장재의 적용은 교량경관의 개선 및 향상에 전반적인 영향을 미치는 것으로 나타났다. 특히, 형식미학적 관점의 14개 항목 중 질감, 주변과의 관계, 쾌적성, 조화성은 외장재의 적용 시 교량경관의 시각적·미적 향상에 대한 기여도가 높은 항목으로 판단할 수 있다. 따라서 향후 상기에 제시된 자료들이 교량용 외장재의 설계에 참고 될 필요가 있다. The bridges which were constructed in the initial growth period in which the development of cities was active, on the other hand, had only focused on the construction of rational bridges concentrated on only the functions and economic feasibility. The bridges which were built in such a periodic background mostly have a considerably low level of aesthetic consideration. In addition, the bridges that were constructed during the period mostly have high degree of visual pollution or physical aging on the exterior due to erosion on the surface and settlement of pollutants because of their continuous exposure to the external environments for a long time. Thus, the exterior of those bridges are becoming more horrid as the time passes. In order to solve such issues, the relevant local governments are conducting landscape improvement projects to put efforts for enhancement of bridge landscapes through demolishing and replacement of bridges with lowered functions as well as renovation projects for those with insufficient aesthetic appreciation. Going along with the atmosphere, the use of finish materials for bridges is increasing. Also, people are paying attention to the finish materials for bridges as an effective alternative to improve bridge landscapes of existing bridges. Furthermore, they are being reflected in advance when designing the landscapes for special structures in the district units or planning landscapes of new towns. Thus, it is predicted that the use of finish materials for bridges to improve the formativeness and landscape beauty will increase. Whereas, the existing literature and research data related to finish materials for bridges mostly only mention the parts on usefulness and functionality of finish materials for bridges. Consequently, it is time that studies and analysis on the aesthetic aspect are required. The purpose of this study is to provide basic information and data which can serve as a reference in the course of reflecting the finish materials for bridges in the design. The details are as below. First, the current status of Korea and Japan were reviewed through literature and research reports on finish materials for bridges and an overall technologic study was conducted. Second, in order to conduct visual and aesthetic evaluations, subjects were selected. Then, the current status of the subject bridge landscapes was researched and analyzed. Third, based on the landscape control point, photographs were taken for visual evaluation. Fourth, by introducing the evaluation index of formative aesthetic aspect, quantitative evaluation was executed. Fifth, the preferences per bridge, per application of finish material, and per material of exterior were analyzed. By using the SPSS ver18, the reliability analysis, t-test per group, and one way-ANOVA were each conducted. In conclusion, the application of finish material for bridges exhibited its overall influence over improvement of bridge landscapes. Among the 14 items in the formative aesthetic aspect, the texture, relationship with the surrounding, agreeableness, and harmony were those with the highest contribution to the visual and aesthetic improvement of bridge landscapes when applying finish materials. Consequently, efforts need to be made to refer to the above details when planning application of finish materials to review and select preferential factors appropriate to the structural forms and the surrounding landscapes of the subject bridge and the surrounding environment to reflect a finish material which can bring out the aesthetics of the bridge with outstanding design on the design.

A Study on Live Load Deflection Criteria of Long-Span Steel Bridges

박기정,김도영,황의승 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.6

Under-clearance of bridges is one of the major considerations when planning and designing bridges. Especially for seacrossing bridges, under-clearance is more important for safe passage of ships. Long span cable bridges with steel orthotropic deck usually show relatively large defl ections and excessive defl ections may be not only disadvantageous to the clearance plan, but also a problem in bridge serviceability. The clearance of sea-crossing bridge is designed with air draft from the waterline to top of mast, ship’s trim, psychological free space, sea level, height of wave and bridge defl ection by live loads. At design stage, bridge engineers need a live load defl ection limit to ensure adequate clearance. The limitation of live load defl ection is also considered for ensuring the serviceability of vibration of bridges. For vibrational serviceability, the live load defl ection limit is expressed as a ratio to the span or the formula by natural frequency. On the other hand, some standards specify vibration serviceability limit by peak or root-mean-square (RMS) acceleration. The purpose of this study is to propose new defl ection limit criteria for long span steel cable bridges based on analysis and long-term measurement data. Structural analysis was performed on two steel suspension and three steel cable-stayed bridges with more than 200 m of main span under design live load model of DL24 and new live load model KL510 in limit state design code. Also, the defl ection limit criterion was evaluated by probabilistic method using the defl ection data measured for 1 year. The results of this study are expected to be useful data for bridge engineers designing long span steel cable bridges.

3D simulation of railway bridges for estimating fundamental frequency using geometrical and mechanical properties

Moazam, Adel Mahmoudi,Hasani, Nemat,Yazdani, Mahdi Techno-Press 2017 Advances in computational design Vol.2 No.4

There are many plain concrete arch bridges in Iran that have been used as railway bridges for more than seventy years. Owe to the fact that these bridges have not been designed seismically, and even may be loaded under high-speed trains, evaluation of fundamental frequencies of the bridges against earthquake and high-speed train vibrations is necessary for considering dynamics effects. To evaluate complex behavior of these bridges, results of field tests are useful. Since it is not possible to perform field tests for all arch bridges, these structures should be simulated correctly by computers for structural assessment. Several parameters are employed to describe the bridges, such as number of spans, length of spans, geometrical and material properties. In this study, results of field tests are used for modal analysis and adapted for 64 three dimensional finite element models with various physical parameters. Computer simulations show length of spans has important effect on fundamental frequencies of plain concrete arch bridge and modal deformations of bridges is in longitudinal and transverse directions. Also, these results demonstrate that fundamental frequencies of bridges decrease after increasing span length and number of spans. Plus, some relations based in the number of spans (n) and span length (l) are proposed for calculation of fundamental frequencies of plain concrete arch bridge.

리스크매트릭스를 활용한 중소규모 교량의 유지관리 시나리오 기법 개발

박현찬 ( Hyun-chan Park ),신병길 ( Byoung-gil Shin ),조중연 ( Choong-yuen Cho ),김영민 ( Young-min Kim ),장범수 ( Buhm-soo Chang ) 한국구조물진단유지관리공학회 2021 한국구조물진단유지관리공학회 논문집 Vol.25 No.6

본 논문은 3종 및 법정 외 교량인 중소규모 교량에 대한 유지관리 체계를 수립하여 제안하는데 그 목적을 두고 있다. 국내 교량은 1, 2종 교량과 3종 및 법정 외 교량으로 구분된다. 3종 및 법정외 교량의 개소수는 많으나 1, 2종 교량에 비해 상대적으로 중요도가 낮은 것으로 판단된다. 따라서 본 논문에서는 이러한 중소규모 교량에 대한 유지관리 시나리오 체계를 수립하고자 한다. 하지만 중소규모 교량의 경우 그 개소수가 많아 1, 2종 교량과 같이 모든 교량에 대해 성능평가를 실시하는데 인력과 예산의 문제가 있다. 이에 따라 본 연구는 리스크 매트릭스 기법을 기반으로 교량의 기본적인 현황정보를 이용하여 현재 성능평가가 우선적으로 수행되어야할 교량을 선정하기 위한 기법을 개발하였으며, 개발된 기법에 대하여 실제 공용중인 교량을 대상으로 적용하였다. This paper is a maintenance system for bridge represented by Class 3 and other than by law bridges. Domestic bridge are divided into Class 1 & 2 bridges and Class 3 & other than by law bridges. The number of type 3 and other than by law bridges is very large. But, it is considered to be of relatively low importance compared to Class 1 & 2 Bridge Bridge. So, in this paper is propose a maintenance system and procedure for small & medium-sized bridges. However, because the number of small & medium-sized bridges is large, it is not possible to evaluate the performance of all bridges like Class 1 & 2 bridge. The reason is the lack of manpower and budget. Based on the Risk Matrix method, a maintenance procedure was created to select the bridge for which performance evaluation should be performed first. For this purpose, basic information of the bridge is used. And, the developed maintenance procedures were applied to the bridges in actual use.

Fragility curves for the typical multi-span simply supported bridges in northern Pakistan

Muhammad Waseem,Enrico Spacone 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.64 No.2

Bridges are lifeline and integral components of transportation system that are susceptible to seismic actions, their vulnerability assessment is essential for seismic risk assessment and mitigation. The vulnerability assessment of bridges common in Pakistan is very important as it is seismically very active region and the available code for the seismic design of bridges is obsolete. This research presents seismic vulnerability assessment of three real case simply supported multi-span reinforced concrete bridges commonly found in northern Pakistan, having one, two and three bents with circular piers. The vulnerability assessment is carried through the non-linear dynamic time history analyses for the derivation of fragility curves. Finite element based numerical models of the bridges were developed in MIDAS CIVIL (2015) and analyzed through with nonlinear dynamic and incremental dynamic analyses, using a suite of bridge-specific natural spectrum compatible ground motion records. Seismic responses of shear key, bearing pad, expansion joint and pier components of each bridges were recorded during analysis and retrieved for performance based analysis. Fragility curves were developed for the bearing pads, shear key, expansion joint and pier of the bridges that first reach ultimate limit state. Dynamic analysis and the derived fragility curves show that ultimate limit state of bearing pads, shear keys and expansion joints of the bridges exceed first, followed by the piers ultimate limit state for all the three bridges. Mean collapse capacities computed for all the components indicated that bearing pads, expansion joints, and shear keys exceed the ultimate limit state at lowest seismic intensities.

Dynamic response of railway bridges traversed simultaneously by opposing moving trains

Rezvani, Mohammad Ali,Vesali, Farzad,Eghbali, Atefeh Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.46 No.5

Bridges are vital components of the railroads. High speed of travel, the periodic and oscillatory nature of the loads and the comparable vehicle bridge weight ratio distinguish the railway bridges from the road bridges. The close proximity between estimations by some numerical methods and the measured data for the bridge-vehicle dynamic response under the moving load conditions has boosted the confidence in the numerical analyses. However, there is hardly any report regarding the responses of the railway bridges under the effect of the trains entering from the opposite directions while running at unequal speed and having dissimilar geometries. It is the purpose of this article to present an analytical method for the dynamic analysis of the railway bridges under the influence of two opposing series of moving loads. The bridge structural damping and many modes of vibrations are included. The concept of modal superposition is used to solve for the system motion equations. The method of solution is indeed a computer assisted analytical solution. It solves for the system motion equations and gives output in terms of the bridge deflection. Some case studies are also considered for the validation of the proposed method. Furthermore, the effects of varying some parameters such as the distance between the bogies, and the bogie wheelset distance are studied. Also, the conditions of resonance and cancellation in the dynamic response for a variety of vehicle-bridge specifications are investigated.

규칙 기반 분류 기법을 활용한 도로교량 안전등급 추정 모델 개발

정세환(Chung Se hwan),임소람(Lim So ram),지석호(Chi Seok ho) 한국BIM학회 2016 KIBIM Magazine Vol.6 No.2

Road bridges are deteriorating gradually, and it is forecasted that the number of road bridges aging over 30 years will increase by more than 3 times of the current number. To maintain road bridges in a safe condition, current safety conditions of the bridges must be estimated for repair or reinforcement. However, budget and professional manpower required to perform in-depth inspections of road bridges are limited. This study proposes an estimation model for safety rating of road bridges by analyzing the data from Facility Management System (FMS) and Yearbook of Road Bridges and Tunnel. These data include basic specifications, year of completion, traffic, safety rating, and others. The distribution of safety rating was imbalanced, indicating 91% of road bridges have safety ratings of A or B. To improve classification performance, five safety ratings were integrated into two classes of G (good, A and B) and P (poor ratings under C). This rearrangement was set because facilities with ratings under C are required to be repaired or reinforced to recover their original functionality. 70% of the original data were used as training data, while the other 30% were used for validation. Data of class P in the training data were oversampled by 3 times, and Repeated Incremental Pruning to Produce Error Reduction (RIPPER) algorithm was used to develop the estimation model. The results of estimation model showed overall accuracy of 84.8%, true positive rate of 67.3%, and 29 classification rule. Year of completion was identified as the most critical factor on affecting lower safety ratings of bridges.

고속도로 교량의 개선된 안전성 평가방안을 위한 실측자료에 기초한 공용 내하력 검토

이종호(Lee Jong Ho),한성호(Han Sung Ho),신재철(Shin Jae Chul) 대한토목학회 2009 대한토목학회논문집 A Vol.29 No.6A

고속도로 교량의 안전성은 주요 구조부재의 정밀육안검사, 비파괴 현장시험 및 재료시험 등의 결과를 바탕으로 외관 상태등급을 검토하고, 현장재하시험 결과에 의해 공용 내하력을 산정함으로써 평가되고 있다. 그러나 교량의 공용 내하력이 설계기준에 비하여 상당히 낮은 상태임에도 불구하고, 실제 외관 상태등급은 비교적 양호한 교량이 상당수 있는 것으로 검토되고 있다. 또한 비슷한 준공시기 및 구조형식을 갖는 교량이라도 여러 가지 조건에 따라 공용 내하력은 큰 차이를 나타내는 것을 확인할 수 있다. 따라서 본 연구에서는 고속도로 교량의 현황, 외관 상태등급 및 유지관리 위한 안전진단 및 보수ㆍ보강방안 등을 고찰한 후, 기존 고속도로 교량의 안전성 평가에 관한 다양한 문제점을 제시하였다. 400여 개소의 고속도로 교량 실측자료를 기초로 교량형식, 공용기간, 설계활하중, 외관 상태등급 및 교통량을 변수로 하여 공용 내하력을 정량적으로 비교ㆍ분석하였다. 본 연구결과는 합리적인 고속도로 교량 안전성 평가를 위한 기초자료를 제공할 것으로 기대된다. The safety of expressway bridges was estimated by checking the external condition rank based on the nondestructive inspection and material test and by measuring load carrying capacity based on the result of load test. Although the load carrying capacity of the bridges was clearly low compared to the design standard, it was examined that many of the bridges have good external condition rank relatively. Also, it can be assured that load carrying capacity shows a considerable difference according to various condition even though the bridges have similar construction year and a structural type. Therefore, this study showed various problems of the current safety measurement of expressway bridges by considering the status of the expressway bridges, external condition rank, and method of safety diagnosis and repair, rehabilitation for maintenance. Based on the existing data of over 400 expressway bridges, the load carrying capacity was analyzed quantitatively considering bridge type, serviced life, design live load, external condition rank and traffic count as variables. The result of this study will be expected to provide the basic information for a reasonable safety assessment of expressway bridge.

Behavior of Bridge Bearings for Railway Bridges under Running Vehicle

Choi, Eun-Soo,Yu, Wan-Dong,Kim, Jin-Ho,Park, Sun-Hee The Korean Society for Railway 2012 International Journal of Railway Vol.5 No.1

Open steel plate girder (OPSG) bridges are the most prevalent railroad bridge type in Korea, constituting about 40% of all railroad bridges. Solid steel bearings, known as line type bearings, are placed in most OSPG railway bridges. However, the line type rigid bearings generate several problems with the bridge's dynamic behavior and maintenance in service. To compare and investigate the dynamic behaviors of line type, spherical and disk bearings, the vertical displacements of each bearing, including fixed and expansion type, under running vehicles are measured and analyzed. The displacements of disk and spherical bearings are measured after replacing the line type bearings with spherical and disk bearings. This study also analyzed dynamic behaviors of bridges. Furthermore, the deformation of the PTFE (Polytetrafluoroethylene) plate that is placed inside of expansion type spherical and disk bearings is measured and its effect on the dynamic behavior of the bridges is discussed. The up-lift phenomenon at the bearings installed for the steel bridges is estimated. The vertical displacements at mid-span of the bridges are compared according to the bearing types. Finally, the 1st mode natural frequencies are estimated, and the relationship to the vertical displacement is discussed.

Behavior of Bridge Bearings for Railway Bridges under Running Vehicle

Eunsoo Choi,Wan-Dong Yu,Jinho Kim,Sunhee Park 한국철도학회 2012 International Journal of Railway Vol.5 No.1

Open steel plate girder (OPSG) bridges are the most prevalent railroad bridge type in Korea, constituting about 40% of all railroad bridges. Solid steel bearings, known as line type bearings, are placed in most OSPG railway bridges. However, the line type rigid bearings generate several problems with the bridge’s dynamic behavior and maintenance in service. To compare and investigate the dynamic behaviors of line type, spherical and disk bearings, the vertical displacements of each bearing, including fixed and expansion type, under running vehicles are measured and analyzed. The displacements of disk and spherical bearings are measured after replacing the line type bearings with spherical and disk bearings. This study also analyzed dynamic behaviors of bridges. Furthermore, the deformation of the PTFE (Polytetrafluoroethylene) plate that is placed inside of expansion type spherical and disk bearings is measured and its effect on the dynamic behavior of the bridges is discussed. The up-lift phenomenon at the bearings installed for the steel bridges is estimated. The vertical displacements at mid-span of the bridges are compared according to the bearing types. Finally, the 1st mode natural frequencies are estimated, and the relationship to the vertical displacement is discussed.