강박스-트러스 하이브리드 곡선 교량의 거동 분석

장민서,김정훈,김종민,강영종 한국방재학회 2012 한국방재학회논문집 Vol.12 No.4

Steel Box-Truss Hybrid bridge consisted with steel box type in positive moment that is allowed to resist with low depth and truss type in negative moment not only has restriction of delivery but has to use high depth is new type bridge. This can be used as 80m~150m long span bridge and is economical structural type. But safety of truss type is concerned because of torsion that occurs when Steel Box-Truss Hybrid bridge applies a curved bridge. Therefore, it is necessary to analyse and evaluate straight and curved bridge for commercialization of Steel Box-Truss Hybrid bridge. In this study, structural analysis of Steel Box-Truss hybrid curved bridge with various curvature is performed and compared with member force and displacement of Steel Box-Truss Hybrid straight bridge. Also the applicable limited curvature of Steel Box-Truss Bridge form is proposed. 강박스-트러스 하이브리드(HiTAB: Hybrid Truss And Box) 교량은 낮은 형고로 저항이 가능한 정모멘트 구간에는 강박스구조를 활용하고, 운반에 제약을 받을 뿐만 아니라 높은 형고의 거더를 활용해야 하는 부모멘트 구간에는 트러스 구조를 적용한 신형식 교량이다. 이는 경간장 80~150 m 내외의 장경간 교량으로 활용이 가능하여 경제성이 우수한 구조형식이지만, 곡선구간 적용 시 교량에 발생하는 비틀림으로 인해 트러스 구조의 안전성이 저하될 우려가 있다. 그러므로 강박스-트러스 하이브리드 교량의 상용화를 위해서는 직선 교량 뿐만 아니라 곡선 교량의 거동 분석 및 평가가 반드시 필요하다. 따라서 본 연구에서는 다양한 곡률을 가지는 강박스-트러스 하이브리드 곡선 교량에 대해 구조해석을 수행하였으며, 이를 직선 교량의 부재력과처짐에 대한 비교를 통해 거동 분석 및 평가를 수행하였다. 또한 강박스-트러스 하이브리드 교량의 직선 형식으로 곡선 교량에적용 가능한 한계곡률을 제시하였다.

A New Composite Truss Bridge and a Study on Its Dynamic Characteristics with FE and Experimental Methods

Xiaoli Xie,Yang Huang,Xia Qin 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.3

Improvements to the dynamic characteristics and stiffness of composite girder bridges are necessary to expand their applications and capabilities. The natural frequency of a bridge directly reflects the dynamic characteristics of a structure. From the calculation principle for the natural frequency, the natural frequencies of a bridge can be significantly increased if the load increases slightly while the structural stiffness increases significantly. Based on this, a new type of concrete-steel composite truss bridge is proposed. The new bridge has a reasonable new arrangement for the position of the concrete and steel, according to the bending moment law for continuous girders. The mechanical analysis of the new bridge shows that it has the characteristic of adding a small amount of load at a reasonable position, which can significantly improve the stiffness. Therefore, it is possible to achieve the purpose of improving the dynamic characteristics so that they are far better than those of a conventional composite truss bridge. To further study the dynamic characteristics of the new composite truss bridge, the finite element (FE) method was used to analyse the new bridges, and the results are compared with those of conventional composite truss bridges. Furthermore, several parameters that influence the dynamic characteristics of the new composite truss bridge were studied. Finally, the dynamic characteristics of the small-span new bridge were studied by finite element analysis (FEA) and experiment. The results show that the new composite truss bridges with different span arrangements and different second-stage dead loads always have better natural frequencies and stiffness advantages. Therefore, the new composite truss bridge is suitable for girder bridges with strict requirements for their stiffness and dynamic characteristics, especially for super-long span high-speed railway girder bridges.

Reliability evaluation of steel truss bridge due to traffic load based on bridge weigh-in-motion measurement

Widi Nugraha,Indra Djati Sidi,Made Suarjana,Ediansjah Zulkifli Techno-Press 2022 Structural monitoring and maintenance Vol.9 No.4

Steel truss bridge is one of the most widely used bridge types in Indonesia. Out of all Indonesia's national roads, the number of steel truss bridges reaches 12% of the total 17,160 bridges. The application of steel truss bridges is relatively high considering this type of bridge provides advantages in the standardization of design and fabrication of structural elements for typical bridge spans, as well as ease of mobilization. Directorate of Road and Bridge Engineering, Ministry of Works and Housing, has issued a standard design for steel truss bridges commonly used in Indonesia, which is designed against the design load in SNI 1725-2016 Bridge Loading Standards. Along with the development of actual traffic load measurement technology using Bridge Weigh-in-Motion (B-WIM), traffic loading data can be utilized to evaluate the reliability of standard bridges, such as standard steel truss bridges which are commonly used in Indonesia. The result of the B-WIM measurement on the Central Java Pantura National Road, Batang - Kendal undertaken in 2018, which supports the heaviest load and traffic conditions on the national road, is used in this study. In this study, simulation of a sequences of traffic was carried out based on B-WIM data as a moving load on the Australian type Steel Truss Bridge (i.e., Rangka Baja Australia -RBA) structure model with 60 m class A span. The reliability evaluation was then carried out by calculating the reliability index or the probability of structural failure. Based on the analysis conducted in this study, it was found that the reliability index of the 60 m class Aspan for RBA bridge is 3.04 or the probability of structural failure is 1.18 × 10^-3, which describes the level of reliability of the RBA bridge structure due to the loads from B-WIM measurement in Indonesia. For this RBA Bridge 60 m span class A, it was found that the calibrated nominal live load that met the target reliability is increased by 13% than stated in the code, so the uniform distributed load will be 7.60 kN/m² and the axle line equivalent load will be 55.15 kN/m.

Study on Redundancy Improvement for Truss Bridges Focusing on the Geometry and Placement Pattern of Additional Braces

Keiji Tajima,Hirokazu. Ishiguro,Toshihiko Aso 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.4

This paper describes a study on improving redundancy in a 240 m span steel Pratt truss bridge. Redundancy was evaluated from two perspectives. The fi rst perspective was how many members would induce bridge collapse owing to their own damage, and the second perspective was how many members would be damaged owing to another member’s damage. Members corresponding to these two perspectives were widely present throughout the subject truss bridge. As a measure to improve redundancy of the subject truss bridge, the method of installing alternative load paths by retrofi tting additional braces was studied. Three proposals with diff erent geometry of the additional braces were compared, and "X bracing", which equipped X-shaped braces by adding braces in the opposite direction to the existing diagonal member, demonstrated excellent performance. In addition, the eff ect of the method retrofi tting the cable along the member was also studied. Next, the placement patterns of "X bracing" on 18 truss panels of the subject truss bridge were examined using an optimization technique. It was clarifi ed that examination of the placement for the additional braces was important for the effi cient improvement of redundancy, and that the optimum placement of X bracing was in the alternating areas. Finally, the buckling gusset plate of the I-35 W bridge was also in the alternating area, suggesting that reinforcement of the alternating area might be important for redundancy of truss bridges.

A framework for carrying out train safety evaluation and vibration analysis of a trussed-arch bridge subjected to vessel collision

He Xia,Chaoyi Xia,Nan Zhang,Qin Ma,Xuan Wu 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.59 No.4

Safety is the prime concern for a high-speed railway bridge, especially when it is subjected to a collision. In this paper, an analysis framework for the dynamic responses of train-bridge systems under collision load is established. A multi-body dynamics model is employed to represent the moving vehicle, the modal decomposition method is adopted to describe the bridge structure, and the time history of a collision load is used as the external load on the train-bridge system. A (180+216+180) m continuous steel trussedarch bridge is considered as an illustrative case study. With the vessel collision acting on the pier, the displacements and accelerations at the pier-top and the mid-span of the bridge are calculated when a CRH2 high-speed train running through the bridge, and the influence of bridge vibration on the running safety indices of the train, including derailment factors, offload factors and lateral wheel/rail forces, are analyzed. The results demonstrate that under the vessel collision load, the dynamic responses of the bridge are greatly enlarged, threatening the running safety of high-speed train on the bridge, which is affected by both the collision intensity and the train speed.

An Insight to the Dynamic Amplification Factor for Steel Truss Girder Bridge

S. Parida,S. Talukdar 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.4

The design of bridge is accomplished by magnifying static live load eff ect by a factor known as impact factor. In design codes of most of the countries, impact factor is provided as a function of bridge length or fundamental natural frequency. However, many studies recently conducted on bridge vehicle dynamics found other infl uencing parameters for the impact factor. In the present paper, the dynamic amplifi cation factor of the steel truss girder bridge has been found out taking bridge–vehicle dynamics using fi nite element method. An uncoupled iterative scheme interfacing the fi nite element software has been proposed to implement vehicle induced pavement force. The dynamic amplifi cation factors have been obtained for diff erent vital component of the steel truss bridge considering the variation of bridge span, vehicle speed, pavement roughness and inter spacing of successive vehicles on the bridge.

Flutter suppression of long-span suspension bridge with truss girder

Wang, Kai,Liao, Haili,Li, Mingshui Techno-Press 2016 Wind and Structures, An International Journal (WAS Vol.23 No.5

Section model wind tunnel test is currently the main technique to investigate the flutter performance of long-span bridges. Further study about applying the wind tunnel test results to the aerodynamic optimization is still needed. Systematical parameters and test principle of the bridge section model are determined by using three long-span steel truss suspension bridges. The flutter critical wind at different attack angles is obtained through section model flutter test. Under the most unfavorable working condition, tests to investigate the effects that upper central stabilized plate, lower central stabilized plate and horizontal stabilized plate have on the flutter performance of the main beam were conducted. According to the test results, the optimal aerodynamic measure was chosen to meet the requirements of the bridge wind resistance in consideration of safety, economy and aesthetics. At last the credibility of the results is confirmed by full bridge aerodynamic elastic model test. That the flutter reduced wind speed of long-span steel truss suspension bridges stays approximately between 4 to 5 is concluded as a reference for the investigation of the flutter performance of future similar steel truss girder suspension bridges.

Flutter suppression of long-span suspension bridge with truss girder

Kai Wang,Haili Liao,Mingshui Li 한국풍공학회 2016 Wind and Structures, An International Journal (WAS Vol.23 No.5

Section model wind tunnel test is currently the main technique to investigate the flutter performance of long-span bridges. Further study about applying the wind tunnel test results to the aerodynamic optimization is still needed. Systematical parameters and test principle of the bridge section model are determined by using three long-span steel truss suspension bridges. The flutter critical wind at different attack angles is obtained through section model flutter test. Under the most unfavorable working condition, tests to investigate the effects that upper central stabilized plate, lower central stabilized plate and horizontal stabilized plate have on the flutter performance of the main beam were conducted. According to the test results, the optimal aerodynamic measure was chosen to meet the requirements of the bridge wind resistance in consideration of safety, economy and aesthetics. At last the credibility of the results is confirmed by full bridge aerodynamic elastic model test. That the flutter reduced wind speed of long-span steel truss suspension bridges stays approximately between 4 to 5 is concluded as a reference for the investigation of the flutter performance of future similar steel truss girder suspension bridges.

한강교량의 야간경관조명에 관한 주관적 평가 -트러스교,아치교를 중심으로-

황민구 ( Min-ku Hwang ),황태연 ( Taeyon Hwang ) 조선대학교 공학기술연구원 2016 공학기술논문지 Vol.9 No.2

This study aims to evaluate the subjective image on the 4 bridges that are truss and arch bridge across the Han River, by questionnaire surveys. Questionnaire surveys were conducted by 135 subjects and were statistically analyzed by SPSS. The results of the study are as follows; ① It was proved that the evaluation of adjectives of truss bridges`` illuminating was higher than it of arch bridge by the profiles. ② It is analyzed that the night time images of the Banghwa, Dongho and Dongjak Grand Bridge has been improved by illuminating. ③ The common factors that are related to the impression on illuminating of truss and arch bridges across the Han River are as follows; ``Evaluation``, ``Potency``, ``Activity`` ④ It was construed that the impression of illuminating was Influenced by four independent variables which were ‘structure of bridges’, ‘daytime images’, ‘color of light sources’ and ‘brightness of light sources’, and the explanation value were 70-82%.

RAMS evaluation for a steel-truss arch high-speed railway bridge based on SHM system

Zhao, Han-Wei,Ding, You-Liang,Geng, Fang-Fang,Li, Ai-Qun Techno-Press 2018 Structural monitoring and maintenance Vol.5 No.1

The evaluation theory of reliability, availability, maintainability and safety (RAMS) as a mature theory of state evaluation in the railway engineering, can be well used to the evaluation, management, and maintenance of complicated structure like the long-span bridge structures on the high-speed railway. Taking a typical steel-truss arch bridge on the Beijing-Shanghai high-speed railway, the Nanjing Dashengguan Yangtze River Bridge, this paper developed a new method of state evaluation for the existing steel-truss arch high-speed railway bridge. The evaluation framework of serving state for the bridge structure is presented based on the RAMS theory. According to the failure-risk, safety/availability, maintenance of bridge members, the state evaluation method of each monitoring item is presented. The weights of the performance items and the monitoring items in all evaluation levels are obtained using the analytic hierarchy process. Finally, the comprehensive serving state of bridge structure is hierarchical evaluated.