Commenced in January 2007
Paper Count: 30174
Seismic Analysis of a S-Curved Viaduct using Stick and Finite Element Models
Abstract:Stick models are widely used in studying the behaviour of straight as well as skew bridges and viaducts subjected to earthquakes while carrying out preliminary studies. The application of such models to highly curved bridges continues to pose challenging problems. A viaduct proposed in the foothills of the Himalayas in Northern India is chosen for the study. It is having 8 simply supported spans @ 30 m c/c. It is doubly curved in horizontal plane with 20 m radius. It is inclined in vertical plane as well. The superstructure consists of a box section. Three models have been used: a conventional stick model, an improved stick model and a 3D finite element model. The improved stick model is employed by making use of body constraints in order to study its capabilities. The first 8 frequencies are about 9.71% away in the latter two models. Later the difference increases to 80% in 50th mode. The viaduct was subjected to all three components of the El Centro earthquake of May 1940. The numerical integration was carried out using the Hilber- Hughes-Taylor method as implemented in SAP2000. Axial forces and moments in the bridge piers as well as lateral displacements at the bearing levels are compared for the three models. The maximum difference in the axial forces and bending moments and displacements vary by 25% between the improved and finite element model. Whereas, the maximum difference in the axial forces, moments, and displacements in various sections vary by 35% between the improved stick model and equivalent straight stick model. The difference for torsional moment was as high as 75%. It is concluded that the stick model with body constraints to model the bearings and expansion joints is not desirable in very sharp S curved viaducts even for preliminary analysis. This model can be used only to determine first 10 frequency and mode shapes but not for member forces. A 3D finite element analysis must be carried out for meaningful results.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1057835Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2001
 Farrar C. R., and Duffey, T. A. (1998). "Bridge modal properties using simplified finite element analysis." J. Bridge Engg.3 (1) ASCE, N.Y., 38- 46.
 Meng, J. Y., and Lui, E. M. (2002). "Refined stick model for dynamic analysis of skew bridges." J. Bridge Engg. 7(3) ASCE, N.Y., 184-194.
 Abeysinghe, R.S., Gavaise, E., Rosignoli, M. and Tzaveas, T.(2002). "Pushover analysis of inelastic seismic behavior of Greveniotikos bridge." J. Bridge Engg. 7(2), 115-126.
 Samaan, M., Kennedy, J.B. and Sennah, K.(2007) "Dynamic analysis of curved continuous multiple-box girder bridges." J. Bridge Engg. 12(2) ASCE, N.Y., 184-193.
 Wang, T.L., Huang, D. amd Shahawy, M. (1996). "Dynamic behavior of continuous and cantilever thin-walled box girder bridges." J. Bridge Engg. 1(2), 67-75.
 Brudette, N.J. and Elnashi, A.M. (2008). "Effect of asynchronous earthquake motion on complex bridges II: Results and implications on assessment." J. Bridge Engg. 13(2) ASCE, N.Y., 166-172.
 Brudette, N.J., Elnashi, A.S., Lupoi, A. and Sextos, A.G.(2008). "Effect of asynchronous earthquake motion on complex bridges I: Methodology and input motion." J. Bridge Engg. 13(2) ASCE, N.Y., 158-165.
 DesRoches, R., Choi, E., Leon, R.T., Dyke, S.J. and Aschheim, M.(2004) "Seismic response of multiple span steel bridges in central and southeastern United States. I:As built." J. Bridge Engg. 9(5) ASCE, N.Y., 464-472.
 Mwafy, A., Elnashai, A. and Yen, W. H. (2007). "Implications of design assumptions on capacity estimates and demand predictions of multispan curved bridges." J. Bridge Engg. 12(6) ASCE, N.Y., 710-726.
 Nielson, B. G., and DesRoches, R. (2007). "Seismic performance assessment of simply supported and continuous multispan concrete girder highway bridges." J. Bridge Engg. 12(5) ASCE, N.Y., 611-620.
 Rashidi, S. and Saadeghvaziri, M. A.(1997). "Seismic modeling of multispan simply-supported bridges using ADINA." Computer & Structures, 64(5/6), 1025-1039.
 Saadeghvaziri, M. A. and Yazdani-Motlagh, A. R. (2008). "Seismic behavior and capacity/demand analyses of three multi-span simply supported bridges." Engineering Structures, 30, 54-66.
 Dicleli, M. (2002). "Seismic design of lifeline bridge using hybrid seismic isolation."J. Bridge Engg. 7(2) ASCE, N.Y., 94-103.
 IRC6, 2000, Standard specifications and code of practice for road bridges, Section: II Load and stresses, Indian Road Congress, New Delhi.
 SAP2000 (2008), Integrated structural analysis and design software. Version 12, Computers and Structures, Berkeley, Calif.
 ATC-32 (1996a), Improved Seismic Design Criteria for California Bridges: Provisional Recommendations, Applied Technology Council, Redwood City, California.
 ATC-32-1 (1996b), Improved Seismic Design Criteria for California Bridges: Resource Document, Applied Technology Council, Redwood City, California.