Behavior of Girder-Floor Beam Connections in Prestressed Concrete Pedestrian Bridges Subjected to Lateral Impact Loads Eray Baran, Ph.D. 1 ; Arturo E. Schultz, Ph.D. 2 ; and Catherine E. French, Ph.D., P.E. 3 Abstract: Each year a large number of concrete bridges are subjected to impact by overheight vehicles or vehicles carrying overheight objects. Most bridge owners in the United States are concerned with the increasing trend of bridges impacted by overheight vehicles, thereby increasing the urgency to evaluate the resistance of bridges to lateral impact loads. The present integrated numerical and experimental study investigates the behavior of a critical connection, between girders and floor beams, in a type of bridge that is considered to be particularly vulnerable, prestressed concrete through-girder PCTG pedestrian bridges. PCTG pedestrian bridges com- prise precast, prestressed concrete girders connected by cast-in-place, reinforced concrete floor beams and a cast-in-place deck. The deck is connected to the floor beams only, and the floor beams are joined to the girders using embedded concrete anchors. The investigation combines three-dimensional finite-element analyses with physical testing to elucidate the load-deformation characteristics of the girder- floor beam connections. A series of six girder-floor beam connection subassemblage specimens were built and tested, three of which were subjected to vertical loading, while the other three specimens had a combination of vertical and horizontal load. Three types of anchors were investigated, including two types of loop inserts and one bolt insert. The study revealed that specimen response depends upon the characteristics of the embedded concrete anchors. Deterioration of specimen load capacity was found to be associated with concrete cracking, formation of a cone breakout surface, yielding of the anchors, and fracture of the inserts. The floor beam-girder subassemblages were able to resist large displacements after attaining peak load, even though postpeak load carrying capacity was undermined in most cases. DOI: 10.1061/ASCE0733-94452007133:111670 CE Database subject headings: Bridges, girder; Beams; Connections; Concrete, precast; Bridges, pedestrian; Lateral loads; Deformation; Finite element method; Impact loads. Introduction Each year a large number of concrete bridges are subjected to impact by overheight vehicles or vehicles carrying overheight objects, causing not only structural damage, but in many cases leading to injuries and sometimes even fatalities. Recent bridge inventory surveys have indicated an increasing trend in the number of overheight vehicle collisions in the United States. According to a National Cooperative Highway Research Pro- gram NCHRP study, on average 200 prestressed concrete bridges were damaged each year, and in 80% of these cases the damage was caused by impact from overheight vehicles or loads Shanafelt and Horn 1980. Wardhana and Hadipriono reported 503 cases of bridge failures, including distress, that occurred in the United States from 1989 until 2000 Wardhana and Hadipri- ano 2003. Among 503 incidents, 59 of them were due to collision of a vehicle with bridges, and 14 of those cases included trucks striking the bridge. In 1998, Feldman et al. reported on a survey conducted between 1987 and 1992, which indicated that the oc- currence of impact damage in the State of Texas alone had risen to approximately 50 incidents/ year Feldman et al. 1998. Ac- cording to a Maryland State Highway Administration study, approximately one out of every five overpasses in Maryland has been struck by an overheight vehicle during its lifetime, and one- sixth of these bridges sustained damage that required repairs University of Maryland 2001. Most State Departments of Transportation in the United States are concerned with the increasing trend of bridges impacted by overheight vehicles, and have dealt with the problem by taking simple precautions, such as placing larger warning signs and under-reporting the bridge clearances by several inches, or by taking more costly measures, such as increasing required bridge clearances. However, none of these precautions can ensure the avoidance of vehicular impacts, and the resistance of bridges to lateral impact loads needs to be studied. Review of Previous Research The available literature on behavior of bridges under lateral im- pact loading is limited to highway bridges. Sengupta and Breen 1 Structural Engineer, Walter P. Moore and Associates, Las Vegas, NV 89119. 2 Professor, Dept. of Civil Engineering, Univ. of Minnesota, Minneapolis, MN 55455-0220 corresponding author. E-mail: schul088@umn.edu 3 Professor, Dept. of Civil Engineering, Univ. of Minnesota, Minneapolis, MN 55455-0220. Note. Associate Editor: Yahya C. Kurama. Discussion open until April 1, 2008. Separate discussions must be submitted for individual papers. To extend the closing date by one month, a written request must be filed with the ASCE Managing Editor. The manuscript for this paper was submitted for review and possible publication on February 13, 2006; approved on July 13, 2007. This paper is part of the Journal of Struc- tural Engineering, Vol. 133, No. 11, November 1, 2007. ©ASCE, ISSN 0733-9445/2007/11-1670–1681/$25.00. 1670 / JOURNAL OF STRUCTURAL ENGINEERING © ASCE / NOVEMBER 2007