DYNAMICS OF REINFORCED CONCRETE SLAB OF PEDESTRIAN BRIDGE WITH RIGID REINFORCEMENT

The article is devoted to the actual problem of studying the dynamic response of bent plate structures with reinforcement represented by rigid metal profiles. Such structures can be used in pedestrian bridges or other span structures. A finite element model is built by using the example of a pedestrian bridge slab with reinforcement in the form of steel T-shape profiles. Deformations of concrete, reinforcement, and rigid reinforcement bars are described by a system of solid and shell finite elements, that take into consideration modern models of physical, geometric, and structural nonlinearity. The dynamic impact is modeled at low speed in two variants. The first is a blast load is applied in the middle of the span according to a symmetrical scheme, and the second pursuant to an asymmetric scheme. The structural and inertial damping of vibrations of the damaged system is taken into account. In this case, an implicit integration method is used. The time variation of the dynamic load implies a residual mass of the impacting body that vibrates with the slab structure after the onset of impact. The bond between concrete and stiff rebar is evaluated by the level of cohesion stresses in the vicinity of the profile with maximum strains. The finite element model is verified with a full-scale experiment in which a slab with rigid reinforcement is built and tested. Numerical studies have shown that asymmetrical loading can have a more negative effect on the structure than symmetrical loading, with structure deflections varying by up to 42%. As a result, the effectiveness of experimental theoretical modeling of the dynamics of such structures is shown, which can be used for both typical and individual designs.