Flexural behavior of short reinforced concrete hybrid beams – experiment and numerical simulations

Abstract

The paper presents the experimental results on the influence of the longitudinal reinforcement ratio on the flexural behavior of the short reinforced concrete hybrid beams. The beams are made of two materials: high strength concrete (HSC) in the upper part (in order to take over compressive stresses) and polymer concrete at the
bottom part (in order to withstand tensile stresses). Different longitudinal reinforcement ratios and reinforcement placing on the cross-section were used in order to study its influence on the overall flexural behavior of the beams.
A finite element nonlinear analysis was performed using the LUSAS program. The high strength concrete and the polymer concrete were modeled using linear plane stress elements. The reinforcement was considered as bar type with embedded functions in the plane stress elements. The complete bonding between the reinforcement and the polymer concrete was considered during the initial stages of the simulation.
The contribution of the longitudinal reinforcement to the peak resisted load is negligible once a certain value of Ï is attained. The midspan deflection corresponding to the peak load decreases with the increase in the longitudinal reinforcement ratio. The arrangement of the reinforcement on the cross-section has an important influence both on the load carrying capacity and on the maximum midspan deflection of the beams.