Prediction of the Bending Strength of a Composite Steel Beam–Slab Member Filled with Recycled Concrete

Abstract

This study investigated the structural behavior of a beam–slab member fabricated using a steel C-Purlins beam carrying a profile steel sheet slab covered by a dry board sheet filled with recycled aggregate concrete, called a CBPDS member. This concept was developed to reduce the cost and self-weight of the composite beam–slab system; it replaces the hot-rolled steel I-beam with a steel C-Purlins section, which is easier to fabricate and weighs less. For this purpose, six full-scale CBPDS specimens were tested under four-point static bending. This study investigated the effect of using double C-Purlins beams face-to-face as connected or separated sections and the effect of using concrete material that contains different recycled aggregates to replace raw aggregates. Test results confirmed that using double C-Purlins beams with a face-to-face configuration achieved better concrete confinement behavior than a separate configuration did; specifically, a higher bending capacity and ductility index by about +10.7% and +15.7%, respectively. Generally, the overall bending behavior of the tested specimens was not significantly affected when the infill concrete’s raw aggregates were replaced with 50% and 100% recycled aggregates; however, their bending capacities were reduced, at −8.0% and −11.6%, respectively, compared to the control specimen (0% recycled aggregates). Furthermore, a new theoretical model developed during this study to predict the nominal bending strength of the suggested CBPDS member showed acceptable mean value (0.970) and standard deviation (3.6%) compared with the corresponding test results.

Theoretical Analysis of Composite RC Beams with Pultruded GFRP Beams subjected to Impact Loading

“…Stiffer systems appeared to experience lower accelerations and, as a result, developed lower inertial loads compared to the more miniature rigid beams [11]. Therefore, the composite beams showed greater inertial loads relative to the reference beam [31]. Figure 10 compares the tested and calculated inertial and bending forces with approximately identical values for the NR-I, CG-I, and CGC-I specimens and slight differences for the CS-I specimen.…”