WHEEL LOAD DISTRIBUTION IN STRAIGHT AND SKEWED CONCRETE SLAB BRIDGES STIFFENED WITH RAILINGS

Abstract

This paper presents the parametric investigation of the influence of railings on the wheel load distribution in simply-supported, one-span, three- and four-lane straight and skewed reinforced concrete slab bridges using the finite element method. A total of 96 bridge cases were modeled using finite-element analysis (FEA) and bridge parameters such as span length, slab width, and skew angle are varied within practical ranges. Typical railings built integrally with the bridge were placed on both edges of the deck slabs. AASHTO HS20 truck loadings were positioned transversely and longitudinally to produce maximum longitudinal live load bending moments in the slabs. The FEA wheel load distribution and bending moments were compared with reference straight bridges without railings as well as to the AASHTO Standard Specifications for Highway Bridges and the AASHTO LRFD Bridge Design Specifications. AASHTO overestimates FEA moments for almost all bridge cases and this overestimation increases with the increase in the skew angle, and it is more significant in the presence of two railings. Also, it was found that the reduction in slab moment due to skewness and railings is cumulative. The presence of railings can be considered to be a possible method for strengthening and rehabilitating straight and skewed concrete slab bridges.