Shear Behavior of Open Steel Tube Connectors in Steel⁃UHPC Composite Decks

Steel and ultra⁃high performance concrete(UHPC)composite decks are effective at reducing fatigue cracking and asphalt pavement damage.The shear behavior of innovative open steel tube(OST)connectors in steel⁃UHPC composite decks was investigated by conducting push⁃out tests.The test parameter is the presence of reinforcement in the deck.The load⁃slip curves and shear behavior of the push⁃out specimens were obtained and discussed.The test results indicate that as compared with plain concrete specimens,the limit slip of reinforced specimens decreased by 32%and the shear stiffness increased by 10%,but the ultimate shear capacity was almost the same.The use of UHPC influenced the failure process as it was observed that the OST connector was sheared off at its lower semi⁃tube,followed by the pull⁃out failure of the upper semi⁃tube.A finite element model was verified by tests and was then used to analyze the deformation and failure behaviors of the composite deck with open tubes.The model demonstrates that there is a stress concentration zone at the connector root,and the lower semi⁃tube is the main component that is subject to loads.

Structural Performance of Light Weight Multicellular FRP Composite Bridge Deck Using Finite Element Analysis

Fiber reinforced polymer （FRP） composite materials having advantages such as higher strength to weight than conventional engineering materials, non-corrosiveness and modularization, which should help engineers to obtain more efficient and cost effective structural materials and systems. Currently, FRP composites are becoming more popular in civil engineering applications. The objectives of this research are to study performance and behavior of light weight multi-cellular FRP composite bridge decks （both module and system levels） under various loading conditions through finite element modeling, and to validate analytical response of FRP composite bridge decks with data from laboratory evaluations. The relative deflection, equivalent flexural rigidity, failure load （mode） and load distribution factors （LDF） based on FE results have been compared with experimental data and discussed in detail. The finite element results showing good correlations with experimental data are presented in this work.

Fatigue evaluation of steel-concrete composite deck in steel truss bridge—A case study

An innovative composite deck system has recently been proposed for improved structural performance.To study the fatigue behavior of a steel-concrete composite bridge deck,we took a newly-constructed rail-cum-road steel truss bridge as a case study.The transverse stress history of the bridge deck near the main truss under the action of a standard fatigue vehicle was calculated using finite element analysis.Due to the fact that fatigue provision remains unavailable in the governing code of highway concrete bridges in China,a preliminary fatigue evaluation was conducted according to the fib Model Code.The results indicate that flexural failure of the bridge deck in the transverse negative bending moment region is the controlling fatigue failure mode.The fatigue life associated with the fatigue fracture of steel reinforcement is 56 years.However,while the top surface of the bridge deck concrete near the truss cracks after just six years,the bridge deck performs with fatigue cracks during most of its design service life.Although fatigue capacity is acceptable under design situations,overloading or understrength may increase its risk of failure.The method presented in this work can be applied to similar bridges for preliminary fatigue assessment.