International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395 -0056
Volume: 04 Issue: 03 | Mar -2017
p-ISSN: 2395-0072
www.irjet.net
Parametric Study on Curved Bridges Subjected to Seismic Loading Anurag Deshpande1, H M Jagadisha2, Aravind Galagali3 1Mtech
student, Manipal Institute of Technology, Karnataka, India Professor, Dept of Civil Engineering, Manipal Institute of Technology, Karnataka, India 3Professor, Dept. of Civil Engineering, BVBCET( KLE Technological University), Karnataka, India
2Assistant
---------------------------------------------------------------------***--------------------------------------------------------------------There are many classifications of bridges. The Abstract - As India is developing, the infrastructure is gaining a lot of importance. This project aims at infrastructure development such as bridges. The curvature in the bridges is usually introduced to eliminate the support irregularities or presence of important structures which cannot be demolished. Due to the curvature in the bridge there will be large centrifugal reactions on the vehicles. Apart from the reaction a large torsional moment will be induced on the supporting girders. The column’s location and orientation is also a major design criteria in bridges. When the columns are tilted from the normal angle the column is said to be skewed. Skewed column decreases the stability of structures as seen in the previous literatures. Skewed columns along with some degree of horizontal curvature to the bridges create a lot of instability. In this project bridges subjected to seismic loads and its behavior when the bridge is curved horizontally at deck section and skewed at column or pier section is dealt. The bridge model considered for the project consisted of 2 spans each of 50m, with abutments at both ends and piers at mid section. 2 columns of 1.5m diameter were considered at mid section. In this project Box girder bridge and I girder bridge are compared with horizontal curvature being (R= inf, 150m, 250m) and column skewness with (0, 15, 25 degrees) variation. The results of the study such as modal results and pushover results were tabulated and compared with other bridge models. The software used for the study is CSI Bridge 2016 v18 subjected to seismic load subjected to code of 1893 2002 and IRC 6 for vehicle loading. Key Words: Box girder Bridge, I girder Bridge, Radius of Curvature, Column Skewness
1. INTRODUCTION
From past few decades the infrastructure has seen a great boom in the world. To access any inaccessible areas bridges were built. Hence building bridges became mandatory for infrastructure development. During the ancient time natural bridges were created by nature as in tree trunks extended to the inaccessible areas. Then humans started building their artificial bridges to travel to other side of the valley or non transportable point. The bridges built by humans were usually made of wood or bamboo thatch. As the population increased the need for bigger and sturdier bridge was more. This led for innovation in bridge building techniques thus many types of bridges were formed. Š 2017, IRJET
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bridge which is under study is girder bridges subjected to some radius of curvature that is also known as curved bridge. The curvature in the bridges is usually introduced to eliminate the support irregularities or presence of important structures which cannot be demolished. Due to the curvature in the bridge there will be large centrifugal reactions on the vehicles. Apart from the reaction a large torsional moment will be induced on the supporting girders. Box girders greatly reduce the torsional moment giving greater stability to the structure. The columns location and orientation is also a major design category in bridges. When the columns are tilted from the normal angle the column is said to be skewed. Skewed column decreases the stability of structures as seen in the previous literatures. Skewed columns along with some degree of horizontal curvature to the bridges create a lot of instability. The design of such bridges is always governed by code books and designed very carefully. The study deals with bridges subjected to seismic loads and its behavior when the bridge is curved horizontally at deck section and skewed at column or pier section. The bridge will be subjected to many kinds of loads such as earthquake, wind and vibration loads created by the live load on the bridge. 1.1 Seismic loads Seismic loads create a large impact on the structure. Ground motions are typically measured and quantified in three primary directional components. Two of these components are orthogonal and in the horizontal plane, while the third component is in the vertical direction. The vertical component of ground motion is known to attenuate faster than its horizontal counterparts. Therefore, the impact of vertical ground motion on a bridge structure is typically minimal for bridges located at distances approaching 100 km from active fault. For structures in moderate-to-high seismic regions and close proximity to active faults (<25 km), the vertical component of ground motion is much more prominent, and may be damaging in parallel with horizontal components. 1.2 Vehicle loads For live load purposes vehicular load is taken as the live load on the bridge. The load of vehicles is taken according to the IRC 6. There are 3 types of standards types
ISO 9001:2008 Certified Journal
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