Behavior of Slender, Precast L-Shaped Spandrel Beams
The objective of this research is to study the behavior of slender, precast L-shaped spandrel beams under combined loading conditions. These beams are commonly used in parking structures to transfer vertical loads from deck members to columns. They typically have unsymmetrical cross-sections and are often subjected to heavy, eccentric loading. These factors induce a complex structural response including significant out-of-plane behavior. Traditionally, slender spandrel beams have been reinforced using the torsion and shear provisions of ACI-318 which require closely spaced closed reinforcement to resist spiral cracking typically reported for members subjected to combined shear and torsion.
This thesis describes a research program including loading four full-scale slender L-shaped spandrel beams to failure. A three-dimensional non-linear finite element analytical model was developed to study the behavior of these types of beams at different limit states. The main variables considered in the study are the use of open reinforcement versus traditional closed stirrups and reinforced concrete versus prestressed concrete for L-shaped spandrel beams.
Research findings indicate that out-of-plane bending may control end region behavior for these types of beams. Behavior of beams reinforced with open and closed stirrups were identical up to service loading levels. Based on the results of the experimental data and the analytical model, a simple and rational design methodology, using open reinforcement, is proposed to help practitioners design these types of beams
Advisor:Dr Vernon Matzen; Dr Rudi Seracino; Dr Sami Rizkalla
School:North Carolina State University
School Location:USA - North Carolina
Source Type:Master's Thesis
Date of Publication:06/13/2008