International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 02 | Feb 2025
p-ISSN: 2395-0072
www.irjet.net
SEISMIC ANALYSIS OF CURVED I GIRDER BRIDGE Amit jyoti1, Anwar Alam2 1M. Tech scholar, civil engineering, CIT Ranchi 2Assistant professor, civil engineering, CIT, Ranchi
-------------------------------------------------------------------------- ****---------------------------------------------------------------------------opposed to straight members, these structures are Abstract - This research was conducted with a view to exposed more complicated load distributions as a result understanding the seismic performance of curved I- girder of interaction between bending moment, torsion and bridges concerning curvature radius, span length, and axialforces under the influence of seismic loads. Dynamic intensity of earthquake. Such bridges have been very forces and torsional forces are prominent due to of common in modern infrastructure and grow increasingly curved geometry, and as a result increased stresses, and are vulnerable to seismic events. This M-tech project’s deformations can be caused which vulnerability towards aim was to analyse the seismic performance of curve I damage. Bridge curves arise from various factors such as girder bridges. This project focusing on curvature site limitations, vertical and horizontal alignment, traffic influence, force distribution, deformation pattern during density as well as speed limit variation. Usually, for the seismic events. The Project involved the linear and construction of curve bridges, box girder bridges become nonlinear seismic analysis to understand the static and more advantageous owing to their cellular cross section dynamic response of the bridge. The seismic analysis was that is capable of withstanding high twisting moments. done on the curve bridge model of having 5 span and However, for this case, I girder curve bridge is being length 100m. The earthquake effect was analysed on the studied. Mainly the arch-shaped bridges are accepted bridge model and tried to analyse the forces on bridge, and utilized more because of their effectiveness, stability, displacement in bridge and stress distribution by the use of functionality, cost efficiency, and beauty. Most often they nonlinear time history analysis method. The Advanced CSI are designed to be circular in shape with transitional bridge v26.1.0 software employed to model bridge curves. In the case of curved bridges, torsion being structures and simulates seismic loads, considering induced influences the bridges response in axial, shear nonlinear material behaviour and dynamic response. This and torsional bending moments. This causes a distortion research work was aimed at evaluating, under different on the cross-section of the bridge and leads to seismic scenarios like along the longitudinal direction or differential stresses on the flanges. Edged over by the transverse direction. The stress distribution, deformation, availability of computer technology with sophisticated and mechanisms of possible failure analysed by the analysis tools, the design and analysis of highly curved software. The results show a strong curvature effect on the bridges are now easier. Analytical evaluation of the seismic response of these bridges. The earthquake zone 5 bridges that are curved in plan involves more challenges of Indian region was taken as reference in this project. The compared to straight bridges because they are affected earthquake zone 5 includes the region of Kashmir, POK by both bending and twisting due to the curvature of the border with Nepal, Sikkim and northeast region of India. girders. Hence the section selected for curved bridge These areas are vulnerable to the severe earthquake design should possess a high torsional rigidity for Key words: I girder, seismic, earthquake zone, time effective use of the section. In the case of small curvature history, CSI Bridge bridge, effect of curve angle on BM, SF, TMand VD can be ignored if it is within the limits.
1. INTRODUCTION
1.1. SESISMIC EFFECT ON BRIDGE
Curved I-girder bridges are unique and more complicated than straight bridges. These types of bridges are desirable in hilly and mountainous region where the space and difficult terrain gives less space for highway bridge construction. In hilly and mountainous region curved bridges could be horizontally curved or vertically curve depending upon the terrain. Other than hilly and mountainous region, in city areas where space is constraint these types of curved bridges fulfill the criteria of highways. For city purpose it could be curved steel girder or curved steel box girder and curved concrete box girder. The curved bridges unique geometry brings special challenges to the designers to design structures under earthquake loadings. As
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Impact Factor value: 8.315
1.1.1. SEISMIC DISPLACEMENT: Seismic displacements in bridges refer to the movements or shifts in a bridge structure caused by seismic forces during an earthquake. When an earthquake occurs, ground motions induce forces that travel through the earth, causing the bridge's foundation and superstructure to experience displacement, both horizontally and vertically. These displacements can have significant effects on the bridge's performance, safety, and overall stability. 1.1.2. PIER FAILURE: Pier failure in bridges due to seismic forces is a critical concern in earthquake engineering. During an earthquake, seismic forces can
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