Influence of railings on load carrying capacity of concrete slab bridges

Abstract

This paper presents the results of a parametric study investigating the influence of railings on the load carrying capacity of simply-supported, one-span, multi-lane reinforced concrete slab bridges. A total of 112 bridge cases were modeled using finite element analysis (FEA) subject to AASHTO HS20 truck loadings positioned transversely and longitudinally to produce the maximum bending moments and deflections for cases with and without railings which were compared with AASHTO procedures. Placing two railings on the bridge, AASHTO Standard Specifications procedures overestimated the FEA moments by 100% for one-lane bridges, and by 20% for bridges with two or more lanes. AASHTO LRFD overestimated the FEA moments in all bridge cases by 150% for one-lane, 70% for two-lanes, and a 30% for three- and four-lanes when placing two railings on slab bridges. The results of this study support the AASHTO procedures in designing new concrete slab bridges. However, the paper can also assist engineers in modeling the actual bridge geometry using FEA to account for structural elements such as integral railings in resisting special permit loading on concrete slab bridges.

Keywords

Concrete slab bridges railings multilane bridges finite element analysis AASHTO specifications

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References

AASHTO (2002). Standard specifications for highway bridges, 17th Ed., American Association of State Highway and Transportation Officials (AASHTO), Washington, D.C.

AASHTO (2012). LRFD bridge design specifications, 5th Ed., American Association of State Highway and Transportation Officials (AASHTO), Washington, D.C.

Mabsout

, Tarhini

, Jabakhanji

, Awwad

. Wheel load distribution in simply supported concrete slab bridges. J Bridge Eng. 2004;9(2):147–55.

Davids

, Poulin

, Goslin

. Finite-Element analysis and load rating of flat slab concrete bridges. J Bridge Eng. 2013;18(10):946–56.

Mabsout

, Tarhini

, Frederick

, Kobrosly

. Influence of sidewalks and railings on wheel load distribution in steel girder highway bridges. J Bridge Eng. 1997;2(3):88–96.

Eamon

, Nowak

. Effects of edge-stiffening elements and diaphragms on bridge resistance and load distribution. J Bridge Eng. 2002;7(5):258–66.

Chung

, Liu

, Sotelino

. Influence of secondary elements and deck cracking on the lateral load distribution of steel girder bridges. J Bridge Eng. 2006;11(2):178–87.

Conner

, Huo

. Influence of parapets and aspect ratio on live-load distribution. J Bridge Eng. 2006;11(2):188–96.

Akinci

, Liu

, Bowman

. Parapet strength and contribution to live load response for super load passages. J Bridge Eng. 2008;13(1):55–63.

10.

El Meski

, Mabsout

, Tarhini

. Investigation of AASHTO live-load reduction in reinforced concrete slab bridges. J Bridge Eng. 2011;16(6):792–803.

11.

SAP2000 (2007). Computers and Structures Inc., Berkeley, California.