Analysis and Design of Straight and Skewed Slab Bridges

Abstract

Results of an investigation aimed at determining bending moments and shear forces, required to design skewed concrete slab bridges using the equivalent-beam method are presented in this paper. Straight and skewed slab bridges were modeled using grillage and finite-element models to characterize their behavior under uniform and moving loads with the objective of determining the most appropriate modeling approach for design. A parametric study was carried out on 390 simply supported slabs with geometries covering one to four lane bridges of 3-to 20-m spans and with skew angles ranging from 0 to 60°. The analyses showed that nonorthogonal grillages satisfactorily predict the amplitude and the transverse distribution of longitudinal bending moments and shear forces, and can be used for the analysis of skewed slab bridges. Results of the parametric study indicated that shear forces and secondary bending moments increase with increasing skew angle while longitudinal bending moments diminish. Equations are proposed to include, as part of the equivalent-beam method for skew angles up to 60°, the increase of shear forces and the reduction of longitudinal bending moments. Equations are also given for computing secondary bending moments. A simplified approach aimed at determining the corner forces for straight and skewed bridges is proposed as an alternative to a more-refined analysis. The analyses indicated the presence of high vertical shear stresses in the vicinity of free edges that justifies suggesting to provide shear reinforcement along the slab free edges.

Critical Truck Loading Pattern to Maximize Live Load Effects in Skewed Integral Bridges

“…9,16 In the literature on IBs, it was also found that responses from FE results agree reasonably well with the actual bridge responses. 17 Thus, further verification of the bridge model is not necessary.…”

“…The acute angle between the abutment and a line perpendicular to the positions when designing SIBs or as a tool for developing LLDFs for SIBs. It is worth mentioning that although many research studies [9][10][11] have been conducted on live load effects in conventional skewed bridges, this study is the first attempt to investigate the live load effects in SIBs.…”

Collapse test and moment capacity of the Ruytenschildt reinforced concrete slab bridge

“…These factors have been determined based on a parameter study with linear finite element models. A similar approach, but leading to different factors, is available from Canada (Theoret, Massicotte, & Conciatori, 2012) and similar studies have been carried out in the United States (Menassa, Mabsout, Tarhini, & Frederick, 2007). The number of experiments available in the literature is very limited (R. J. ; R.J. Cope, Rao, & Edwards, 1983;Cusens, 1987), and a first conclusion of these experiments is that the failure mode changes as the skew angle increases and the position of the wheel prints is kept unchanged.…”

New extended grillage methods for the practical and precise modeling of concrete box-girder bridges

“…Balendra and Shanmugam (1985) used the HPGM to model the free vibration of plates and cellular structures and proved that it substantially reduces computer time compared with the conventional methods, and with good accuracy. The HPGM was also introduced into a bridgeroad-vehicle dynamic interaction system for model validation by Nassif et al (2003), and into the design for modeling slab-on-girder structures (The´oret et al, 2012). Zhang et al (2005) investigated the live load distribution of different horizontally curved steel bridges based on generalized grillage systems to develop new formulas.…”