Seismic Analysis of a S-Curved Viaduct using Stick and Finite Element Models
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.
[1] 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.
[2] 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.
[3] 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.
[4] 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.
[5] 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.
[6] 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.
[7] 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.
[8] 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.
[9] 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.
[10] 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.
[11] Rashidi, S. and Saadeghvaziri, M. A.(1997). "Seismic modeling of multispan
simply-supported bridges using ADINA." Computer & Structures,
64(5/6), 1025-1039.
[12] 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.
[13] Dicleli, M. (2002). "Seismic design of lifeline bridge using hybrid
seismic isolation."J. Bridge Engg. 7(2) ASCE, N.Y., 94-103.
[14] IRC6, 2000, Standard specifications and code of practice for road
bridges, Section: II Load and stresses, Indian Road Congress, New
Delhi.
[15] SAP2000 (2008), Integrated structural analysis and design software.
Version 12, Computers and Structures, Berkeley, Calif.
[16] ATC-32 (1996a), Improved Seismic Design Criteria for California
Bridges: Provisional Recommendations, Applied Technology Council,
Redwood City, California.
[17] ATC-32-1 (1996b), Improved Seismic Design Criteria for California
Bridges: Resource Document, Applied Technology Council, Redwood
City, California.
[1] 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.
[2] 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.
[3] 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.
[4] 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.
[5] 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.
[6] 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.
[7] 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.
[8] 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.
[9] 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.
[10] 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.
[11] Rashidi, S. and Saadeghvaziri, M. A.(1997). "Seismic modeling of multispan
simply-supported bridges using ADINA." Computer & Structures,
64(5/6), 1025-1039.
[12] 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.
[13] Dicleli, M. (2002). "Seismic design of lifeline bridge using hybrid
seismic isolation."J. Bridge Engg. 7(2) ASCE, N.Y., 94-103.
[14] IRC6, 2000, Standard specifications and code of practice for road
bridges, Section: II Load and stresses, Indian Road Congress, New
Delhi.
[15] SAP2000 (2008), Integrated structural analysis and design software.
Version 12, Computers and Structures, Berkeley, Calif.
[16] ATC-32 (1996a), Improved Seismic Design Criteria for California
Bridges: Provisional Recommendations, Applied Technology Council,
Redwood City, California.
[17] ATC-32-1 (1996b), Improved Seismic Design Criteria for California
Bridges: Resource Document, Applied Technology Council, Redwood
City, California.
@article{"International Journal of Architectural, Civil and Construction Sciences:51882", author = "Sourabh Agrawal and Ashok K. Jain", title = "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.", keywords = "Bearing, body constraint, box girder, curved viaduct,expansion joint, finite element, link element, seismic, stick model,time history analysis.", volume = "3", number = "2", pages = "87-11", }