Estimation of Extreme Load Effects on Long-Span Bridges Using Traffic Image Data

Elena Alexandra Micu, Eugene John Obrien, Abdollah Malekjafarian, Michael Quilligan


This paper proposes an algorithm for the estimation of extreme intensity of traffic load on long-span bridges. Most Weigh-in-Motion technologies do not operate in congested conditions which are the governing cases for these bridges. In the absence of Weigh-in-Motion data on the bridge itself, a correlation between vehicle weights and their lengths is established here using a (free- flowing) Weigh-in-Motion database. Photographic images of congested traffic are modelled here for three bridges using weights estimated from lengths and one year of Weigh-in-Motion data. The actual weights are taken from the Weigh-in- Motion data, and the results are compared to test the method. The gaps between vehicles are firstly set to a constant value and later to Beta-distributed values according to vehicle type. The intensity of traffic load for all pictures is calculated and compared to the loads obtained from the recorded weights. A return period of 75-year is chosen to evaluate the extreme values of intensity. The probability that intensity of load is being exceeded is obtained using normal probability paper for both recorded and simulated weights. This study demonstrates the feasibility of the proposed concept of using lengths to estimate the extreme traffic load events with acceptable accuracy.


bridge; congestion; long-span; traffic load; vehicle length; Weigh-in- Motion (WIM)

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Aghabayk, K., Sarvi, M., & Young, W. (2012). Understanding the dynamics of heavy vehicle interactions in car-following. Journal of Transportation Engineering, 138(12), 1468-1475.

Al-Kaisy, A. F., Hall, F. L., & Reisman, E. S. (2002). Developing passenger car equivalents for heavy vehicles on freeways during queue discharge flow. Transportation Research Part A: Policy and Practice, 36(8), 725-742.

Al-Kaisy, A., Jung, Y., & Rakha, H. (2005). Developing passenger car equivalency factors for heavy vehicles during congestion. Journal of transportation engineering, 131(7), 514-523.

Attard, M. M., & Stewart, M. G. (1998). A two parameter stress block for high-strength concrete. Structural Journal, 95(3), 305-317.

Bailey, S. (1996). Basic principles and load models for the structural safety evaluation of existing road bridges. Lausanne, Swiss Federal Institute of Technology, 1996 (Doctoral dissertation, thesis).

Benjamin, J. R., & Cornell, C. A. (1970). Probability, Statistics, and Decision for Civil Engineers. New York, New York: McGraw-Hill.

Bruls, A., Croce, P., De Falena, S., & Sedlacek, G. (1996). ENV1991-Part 3: Traffic loads on bridges. Calibration of road load models for road bridges. In Proceedings of IABSE Colloquium on Basis of Design and Actions on Structures (pp. 439-453).

Buckland, P. G. (1991). North American and British long-span bridge loads. Journal of Structural engineering, 117(10), 2972-2987.

Buckland, P. G., McBryde, J. P., Navin, F. P., & Zidek, J. V. (1978). Traffic loading of long span bridges. Transportation Research Record, (665).

Buckland, P. G., Navin, F. P. D., Zidek, J. V., & McBryde, J. P. (1980). Proposed vehicle loading of long-span bridges. Journal of the Structural Division, 106(ASCE 15306 Proceeding).

Caprani, C. C. (2005). Probabilistic analysis of highway bridge traffic loading. Other resources, 1.

Caprani, C. C. (2010). Using microsimulation to estimate highway bridge traffic load. In Proc. 5th Intl. Conf. on Bridge Maintenance, Safety and Management.

Caprani, C. C. (2012). Calibration of a congestion load model for highway bridges using traffic microsimulation. Structural Engineering International, 22(3), 342-348.

Caprani, C. C., & OBrien, E. J. (2008). The governing form of traffic for highway bridge loading. In Proceedings of 4th Symposium on Bridge and Infrastructure Research in Ireland (pp. 53-60). National University of Ireland, Galway.

Caprani, C. C., OBrien, E. J., & Lipari, A. (2016). Long-span bridge traffic loading based on multi-lane traffic micro-simulation. Engineering Structures, 115, 207-219.

Carey, C., OBrien, E. J., Malekjafarian, A., Lydon, M., & Taylor, S. (2017). Direct field measurement of the dynamic amplification in a bridge. Mechanical Systems and Signal Processing, 85, 601-609.

Castillo, E. (1988). Extreme Value Theory in Engineering Academic Press. New York.

Chambers, J., Cleveland, W., Kleiner, B., & Tukey, P. (1983). Graphical methods for data analysis. Belmont, CA: Wadsworth.

Cremona, C. (2001). Optimal extrapolation of traffic load effects. Structural Safety, 23(1), 31-46.

Darmawan, M. S., & Stewart, M. G. (2007). Spatial time-dependent reliability analysis of corroding pretensioned prestressed concrete bridge girders. Structural Safety, 29(1), 16-31.

Ditlevsen, O. (1994). Traffic loads on large bridges modeled as white-noise fields. Journal of engineering mechanics, 120(4), 681-694.

Enright, B. (2010). Simulation of traffic loading on highway bridges.

Enright, B., Carey, C., & Caprani, C. C. (2013). Microsimulation evaluation of Eurocode load model for American long-span bridges. Journal of Bridge Engineering, 18(12), 1252-1260.

Ferrari, P. (1989). The effect of driver behaviour on motorway reliability. Transportation Research Part B: Methodological, 23(2), 139-150.

FHWA (1995). Traffic Monitoring Guide (3rd ed.). Washington, D.C.: U.S. Department of Transportation Federal Highway Administration Guide, T. M., & DOT, U. (1995). FHWA-PL-95-031. Federal Highway Administration, Washington, DC.

Getachew, A. (2003). Traffic load effects on bridges, statistical analysis of collected and Monte Carlo simulated vehicle data (Doctoral dissertation, Byggvetenskap).

Hayrapetova, A. A., O’Connor, A. J., & OBrien, E. J. (2012). Traffic Load Models for Long Span Bridges.

Hwang, E. S., Lee, K. T., & Kim, D. Y. (2012, September). Modelling of truck traffic for long span bridges. In IABSE Congress Report (Vol. 18, No. 14, pp. 1112-1119). International Association for Bridge and Structural Engineering.

Jacob, B. (1991). Methods for the Prediction of Extreme Vehicular Loads and Load Effects on Bridges Report of Subgroup 8, Eurocode 1. Traffic Loads on Bridges.

Jones, M. C., & Kappenman, R. F. (1992). On a class of kernel density estimate bandwidth selectors. Scandinavian Journal of Statistics, 337-349.

Klein, L. A., Mills, M. K., & Gibson, D. R. (2006). Traffic detector handbook: Third editionvolume ii. Federal Highway Administration, Turner-Fairbank Highway Research Center, FHWA-HRT-06-139.

Krauß, S. (1998). Microscopic modeling of traffic flow: Investigation of collision free vehicle dynamics (Doctoral dissertation, Universitat zu Koln.).

Lutomirska, M. (2009). Live load models for long span bridges. Civil Engineering Dissertations and Student Research, 1.

Micu, A., O’Brien, E. J., & Sevillano, E. (2016, August). Application of Image Processing to the Analysis of Congested Traffic. In Civil Engineering Research in Ireland 2016, Galway, Ireland, 29-30 August, 2016. Civil Engineering Research Association of Ireland.

Moses, F. (1979). Weigh-in-motion system using instrumented bridges. Journal of Transportation Engineering, 105(3).

Nowak, A. S., & Collins, K. R. (2012). Reliability of structures. CRC Press.

Nowak, A. S., Lutomirska, M., & Sheikh Ibrahim, F. I. (2010). The development of live load for long span bridges. Bridge Structures, 6(1, 2), 73-79.

Nowak, A. S., & Szerszen, M. M. (1998). Bridge load and resistance models. Engineering structures, 20(11), 985-990.

OBrien, E. J., & Enright, B. (2011). Modeling same-direction two-lane traffic for bridge loading. Structural safety, 33(4-5), 296-304.

OBrien, E. J., Enright, B., & Getachew, A. (2010). Importance of the tail in truck weight modeling for bridge assessment. Journal of Bridge Engineering, 15(2), 210-213.

OBrien, E. J., Hayrapetova, A., & Walsh, C. (2012). The use of micro-simulation for congested traffic load modeling of medium-and long-span bridges. Structure and Infrastructure Engineering, 8(3), 269-276.

OBrien, E. J., Lipari, A., & Caprani, C. C. (2015). Micro-simulation of single-lane traffic to identify critical loading conditions for long-span bridges. Engineering Structures, 94, 137-148.

Paeglitis, A., & Freimanis, A. (2016). Comparision of Constant-Span and Influence Line Methods for Long-Span Bridge Load Calculations. The Baltic Journal of Road and Bridge Engineering, 11(1), 84-91.

DOI: 10.7250/bjrbe.2018-13.427


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