• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.9
• /
• pp.6385-6390
• /
• 2015

With bending moment, torsional moment due to geometric properties as "Initial curvature" acts in horizontally curved I-girder. These behavior causes the secondary effect of bending in minor-axis because of interaction between bending and torsion. The bending and torsion interaction cause a loss of load bearing capacity by induced the early inelastic or plasticity condition in curved girder. Also eccentric load by movements of traffic can increase torsion. However, Equation of interaction between bending and torsion for straight girder, not deal with characteristics of curved girder behavior in previous studies, can be overestimated for ultimate strength in horizontally curved I-girder acting vertical force. Therefore, using more rational, obvious suggestion is required when design curved girder. In this study, we identified the bending-torsional moment interaction for the horizontally curved I-girder of the eccentric load acting by FEM analysis.

• International Journal of Concrete Structures and Materials
• /
• v.10 no.sup3
• /
• pp.1-17
• /
• 2016

Recently, advanced transit systems are being constructed to reduce traffic congestions in metropolitan areas. For these projects, curved bridges with various curvatures are required. Many curved bridges in the past were constructed using aesthetically unpleasant straight beams with curved slabs or expensive curved steel box girders with curved slabs. Therefore, many recent studies have been performed to develop less expensive and very safe precast prestressed concrete (PSC) curved girder. One method of reducing the construction cost of a PSC curved girder is to use a reusable formwork that can easily be adjusted to change the curvature and length of a girder. A reusable and curvature/dimension adjustable formwork called Multi-tasking formwork is developed for constructing efficient precast PSC curved girders. With the Multi-tasking formwork, two 40 m precast PSC box girders with different curvatures were constructed to build a two-girder curved bridge for a static flexural test to evaluate its safety and serviceability performance. The static flexural test results showed that the initial cracking load was 1400 kN, exceeding the design cracking load of 450 kN. Also, the code allowed deflection of 50 mm occurred at a load of 1800 kN, verifying the safety and serviceability of the precast PSC curved bridge constructed using the multi-tasking formwork.

• Journal of Korean Society of Steel Construction
• /
• v.11 no.2 s.39
• /
• pp.131-142
• /
• 1999

The general behavior of the curved girder including the warping effects can be presented as the series of differential equations developed by Vlasov. Generally, bending moment is the most important factor for engineer to decide the section of the girder. In order to accommodate easiness of the structural analysis for the curved girder bridge, this paper suggest the ratios of bending moment of curved gilder to that of straight girder. These ratios are presented by an approximate formula setting central angle ${\theta}(L/R)$ as a variable. The approximate formula of the maximum bending moment ratios and influence lines of all stress resultants can be used to design the three-span curved girder bridges.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2007.04a
• /
• pp.525-530
• /
• 2007

Although just developed in recent years, curved box girder has widely used in modern highway system due to their load resistance capacity as well as aesthetic considerations. According to recent literature reviews on curved box girder designs, distortional load was not considered as much as it deserves to be. In practice, the effect of distributional force is very small in straight bridge systems but yet unknown how it is in curved bridge systems. For the reason, this paper will show up an extensive parametric study on distortional behavior of curved box girder with trapezoidal section. Based on Dabrowski formulas, using finite element method, various bridges were investigated. In this study, following parameters will be included: span length, curvature radius, section height, section width, and internal section angle (web slope). From the obtained results, some initial geometric parameters are proposed for curved box girder bridges.

• Journal of the Korea Concrete Institute
• /
• v.16 no.5 s.83
• /
• pp.709-717
• /
• 2004

The existing AASHTO Standard Specification have some inadequacies in expressing wheel load distribution of bridge which has specific shape of curved bridge instead of straight bridge. Thus, this research presented the finite element analysis and modelling technique of prestressed concrete girder bridge having curved slab and the expression of wheel load distribution was suggested as the ratio of bending moment utilizing the result of finite element analysis of prestressed concrete girder bridge having cowed slab. The considered parameter of girder distribution expression is the curvature of slab, span length, girder space, cross beam space and number of lanes. Though the suggested girder distribution expression is generally underestimated below AASHTO Standard Specification, once the curvature of slab increases, the suggested expression gets larger than AASHTO LRFD Standard Specification.

• Structural Engineering and Mechanics
• /
• v.78 no.3
• /
• pp.255-267
• /
• 2021

The analysis of simply supported single-cell skew-curved reinforced concrete (RC) box-girder bridges is carried out using a finite element based CsiBridge software. The behaviour of skew-curved box-girder bridges can not be anticipated simply by superimposing the individual effects of skewness and curvature, so it becomes important to examine the behaviour of such bridges considering the combined effects of skewness and curvature. A comprehensive parametric study is performed wherein the combined influence of the skew and curve angles is considered to determine the maximum bending moment, maximum shear force, maximum torsional moment and maximum vertical deflection of the bridge girders. The skew angle is varied from 0° to 60° at an interval of 10°, and the curve angle is varied from 0° to 60° at an interval of 12°. The scantly available literature on such bridges focuses mainly on the analysis of skew-curved bridges under dead and point loads. But, the effects of actual loadings may be different, thus, it is considered in the present study. It is found that the performance of these bridges having more curvature can be improved by introducing the skewness. Finally, several equations are deduced in the non-dimensional form for estimating the forces and deflection in the girders of simply supported skew-curved RC box-girder bridges, based upon the results of the straight one. The developed equations may be helpful to the designers in proportioning, analysing, and designing such bridges, as the correlation coefficient is about 0.99.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.1A
• /
• pp.1-13
• /
• 2008

The web of a horizontally curved plate girder bridge is, in general, subject to not only longitudinal flexural in-plane stress but also out-of-plane bending stress. Therefore, the induced stresses in the fillet welded joints at the intersection of the web and flange plates in the curved plate girder bridge can be considerably high, and the welded joints of gusset plates connecting the main girder to the floor beams or sway bracings can be subject to much more severe situation than those in the ordinary straight plate girder bridge. In order to investigate the cause of fatigue crack occurred in a curved girder bridge that has been served in about 23 years, in this study, field load tests have been performed to obtain the stress characteristics at the welded joint under the real traffic flow. Using the test results, we have investigated the causes of the occurrence of various fatigue cracks and have estimated the fatigue lives for the cracks. In addition, the characteristics of structural behavior at welded joint of the curved girder bridge have been examined by comparing the FE analysis and the field test result.

• Journal of Korean Society of Steel Construction
• /
• v.14 no.6
• /
• pp.793-802
• /
• 2002

This study presented a finite element formulation for the dynamic analysis of horizontally curved I-girder bridges. The stiffness and mass matrices of the curved and the straight beam elements are formulated. Each node of both elements has seven degrees of freedom, including the warping degree of freedom. The curved beam element is derived from Kang and Yoo's theory of thin-walled curved beams. The computer program EQCVB has been developed to perform dynamic analyses of various horizontally curved I-girder bridges. The Gupta method is used to solve the eigenvalue problem efficiently, while the Wilson-${\theta}$ method is used for the seismic analysis. The efficiency of EQCVB is demonstrated by comparing solution time with ABAQUS. Using EQCVB, the study is applied to investigate the dynamic behavior of horizontally curved I-girder bridges under seismic loading.

• Steel and Composite Structures
• /
• v.11 no.1
• /
• pp.21-38
• /
• 2011

This study examines the influence of curved, steel, I-girder bridge configuration on girder end reactions and cross frame member forces during seismic events. Simply-supported bridge finite element models were created and examined under seismic events mimicking what could be experienced in AASHTO Seismic Zone 2. Bridges were analyzed using practical ranges of: radius of curvature; girder and cross frame spacings; and lateral bracing configuration. Results from the study indicated that: (1) radius of curvature had the greatest influence on seismic response; (2) interior (lowest radius) girder reactions were heavily influenced by parameter variations and, in certain instances, uplift at their bearings could be a concern; (3) vertical excitation more heavily influenced bearing and cross frame seismic response; and (4) lateral bracing helped reduce seismic effects but using bracing along the entire span did not provide additional benefit over placing bracing only in bays adjacent to the supports.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2008.04a
• /
• pp.50-55
• /
• 2008

In order to investigate and estimate the cause of fatigue crack occurred to curved girder bridge that is used during 20 years, in this study, filed tests to obtain the characteristic of stress hysteresis were performed under the real traffic flows. From these test results, we analyzed the cause of fatigue crack for various fatigue crack patterns. Also, the characteristic of structural behavior for the curved girder bridge were examined from the FE analysis. In addition, to retrofit various fatigue cracks occurred in the bridge, FE analyses considering the characteristics of crack patterns were performed and retrofitting methods were suggested.