Wheel Load Distribution in Continuous Steel Girder Bridges Stiffened with Sidewalks and Railings Moemen Hajjar 1 ; Samer Nuwayhid 2 ; Mounir Mabsout 3 ; and Kassim Tarhini 4 1 Structural Engineer, Dar Al-Handasah, Shair and Partners, Beirut, Lebanon; Former Grad. Stud., Dept. of Civil and Envir. Engineering, Amer. Univ. of Beirut, Lebanon. 2 Structural Engineer, Dar Al-Handasah, Shair and Partners, Beirut, Lebanon; Former Grad. Stud., Dept. of Civil and Envir. Engineering, Amer. Univ. of Beirut, Lebanon. 3 Professor, Dept. of Civil and Envir. Engineering, Amer. Univ. of Beirut, Lebanon. 4 Professor, Dept. of Civil Engineering, U.S. Coast Guard Academy, New London, CT 06320, USA. Abstract This paper presents the results of a parametric study investigating the influence of railings and sidewalks on wheel load distribution in simply-supported two-span steel girder bridges using the finite element method. A total of 300 bridge cases were modeled using three-dimensional finite element analysis (FEA) subject to static wheel loading. Bridge parameters investigated in this study were the span length and girder spacing, for two-lane bridges subjected to AASHTO HS20 truck loadings positioned to produce the maximum positive/negative bending moments. Typical concrete railings and/or sidewalks were placed on either edge or both edges and assumed to be built integrally with the concrete deck slab placed on steel girders. The maximum bending moments were calculated using the FEA results for cases with railings/sidewalks which were compared to the reference bridges without sidewalks or railings and to the AASHTO procedures which do not account for the presence of sidewalks or railings in a bridge deck in their empirical equations. One- and two-span bridges are also compared. The AASHTO load and resistance factor design (LRFD) wheel load distribution formula correlated conservatively with the finite-element results and all were less than the typical AASHTO Standard formula (S/5.5). The presence of sidewalks and railings were shown to increase the load-carrying capacity by as much as 30 % if they were included in the strength evaluation of highway bridges. The results of this investigation will assist structural and bridge engineers in better designing new steel girder bridges as well as evaluating more precisely the load- carrying capacity of existing bridges with sidewalks and railings built as an integral part of the superstructure. Such presence of integral sidewalks and/or railings can also be considered as an adequate and practical method for strengthening and rehabilitating steel girder bridges.