Project Title: Response Of Prestressed Concrete I-Girder Bridges To Live Load Investigator: Dr. Jeffrey Laman Research Assistant: Michael Schwarz Project Duration: May 1998 to June 1999     References: Schwarz*, M.J. and J.A. Laman. "Response of Prestressed Concrete I-Girder Bridges to Live Load," Journal of Bridge Engineering, American Society of Civil Engineers, Vol. 6, No. 1, January/February 2001, pp. 1-8.   Laman, J.A. and M.J. Schwarz*. "Service Live Load in Prestressed Concrete I-Girder Bridges," Proceedings of the ASCE 2000 Structures Congress, Philadelphia, Pennsylvania, May 2000, 6 pages (CDROM).             Design and evaluation of prestressed concrete I-girder bridges is in large part dependent on the transverse load distribution characteristics and the dynamic load amplification as well as service level, live load, and tensile stresses induced in the girders. This study presents the results of field tests conducted on three prestressed concrete I-girder bridges to obtain dynamic load allowance (DLA) statistics, girder distribution factors (GDF), and service level stress statistics. The field-based data is also compared to approximate and numerical model results. Bridge response was measured at each girder for the passage of test trucks and normal truck traffic. The dynamic amplification is observed to be a strong function of peak static stress, a weak function of vehicle speed, and independent of span length, number axles and configuration. GDFs for one and two-lanes are less than code specified GDFs. Results from the numerical grillage models agree closely with experimentally derived results for transverse distribution.
			The Pennsylvania State University