Performance of Bridge Approach Slabs in Bridge Construction: A Case Study

Authors: Aurora Cerri, Niko Pullojani

Abstract:

Long-term differential settlement between the bridge structure and the bridge embankment typically results in an abrupt grade change, causing driver discomfort, impairing driver safety, and exerting a potentially excessive impact traffic loading on the abutment. This paper has analysed a case of study showing the effect of an approaching slab realized in a bridge constructed at Tirane-Elbasan Motorway. The layer thickness under the slab is modeled as homogenous, the slab is a reinforced concrete structure and over that the asphaltic layers take place. Analysis indicates that reinforced concrete approaching slab distributes the stresses quite uniformly into the road fill layers and settlements varies in a range less than 2.50 cm in the total slab length of 6.00 m with a maximum slope of 1/240. Results taken from analytical analysis are compared with topographic measurements done on field and they carry great similarities.

Keywords: Approach slab, bridge, road pavement, differential settlement.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1314963

References:

[1] Ma S. Bridge approach slab analysis and design incorporating elastic soil support, Master Thesis, University of Missouri-Columbia, December 2011.
[2] Hoppe, E. J. Guidelines for the use, design and construction of bridge approach slabs, Virginia Transportation Research Council, Final Report VTRC 00-R4, November, 1999.
[3] Briaud, J. L., James, R. W. and Hoffman, S. B., NCHRP Synthesis of Highway Practice 234: Settlement of Bridge Approaches “Bump at the End of the Bridge”. National Academy Press, Washington, D.C., 1997.
[4] Long, J. H., Olson, S. M., Stark, T. D. and Samara, E. A. Differential movement at embank-bridge structure interface in Illinois, Journal of the Transportation Research Board, Page 53-60, January, 1998.
[5] Zhang, H. L. and Hu C. S., Determination of allowable differential settlement in bridge due to vehicle vibrations, Journal of Bridge Engineering, 12 (2), pp. 154-163, 2007.
[6] AASHTO LRFD Bridge Design Specifications – U.S. Units, Second Edition 1998.
[7] Wahls., H. E., NCHRP synthesis of highway practice 159: design and construction of bridge approaches, Transportation Research Board, National Research Council, Washington D.C., pp. 45, 1990.
[8] Cai, C. S., Shi, X. M., Voyiadjis, G. Z. and Zhang Z. J. Structural performance of bridge approach slabs under embankment settlement, Journal of Bridge Engineering, ASCE, 10 (4), pp. 482-489, 2005.
[9] Computers and Structures Inc. (CSI). SAP2000 Three Dimensional Static and Dynamic Finite Element Analysis and Design of Structures V14.00N. Berkeley, California.
[10] Edward, L W. Three Dimensional Static and Dynamic analysis of Structures” 3rd Edition. Computers and Structures, Inc. Berkeley, California, USA, 2000.