تصرف الاعتاب الفولاذية مزدوجة الوترة والمملؤة بالخرسانة

Behavior of Concrete Filled Double Web Steel Beams

Abstract

The current study aims to investigate the structural behavior of a double web beam filled with different concrete made with a combination of Natural Aggregate (NA) and Recycled Concrete Aggregate (RCA). The aim is achieved by implementing experimental and numerical work.

The experimental work involves the manufacture of seven specimens tested under two concentrated and symmetrical loadings with identical properties (i.e., span length, cross-section, and boundary conditions). The thickness and width of the flange plates of the steel beams were 120 mm and 6 mm, respectively, while the thickness of the web plates was 3 mm and depth 188mm. All beam samples had 1100 mm effective span length. The specimens are classified into two groups, in addition to one beam without concrete as a control beam. The first group included three beams filled with normal concrete (the first one filled in middle region, the second beams filled with two side, the third beams filled full region), while the second group contained three double-web beams which were discussed location filled in first group but only different filled with recycled aggregate concrete. The studied parameters were the type and locations of concrete in a double web steel beam.

The experimental result for the first group of specimens revealed that the filled normal concrete in the web zone caused an increase in the ultimate load by (10.19 % to 55.30 %). Further, The max increase was in the ductility index of the specimen (double web steel fully filled normal concrete) around 568% and increase in their stiffness from (2.6 % to 39 %) if compared with the control beam. While the second group of specimens that filled recycled concrete in the web zone caused an increase in the ultimate load by (9.52 % to 42.03 %).In addition to the max increase in the ductility index of thespecimen (double web steel fully filled recycled concrete) were increased about (380 %) and also increase in their stiffness from (4.5% to 8.03 %) if compared with the control beam.

The numerical work involved using a model non-linear finite element analysis by ABAQUS (2021) software package to conduct the numerical investigation of a double web filled with different types of concrete normal and recycled.There was a good convergence between the experimental and numerical results regarding the ultimate load, maximum deflection, load-deflection curves, and failure mode.The average difference in the ultimate load and the maximum deflection was found to be equal to 5.50 % and 7.90
%, respectively, ensuring the numerical work validity. Two parametric studies of various variables also numerically examined (the effect of concrete compressive strength and steel yield stress). As a result of the parametric studies the increase yield stress for control beam was 310 MPa and 350 MPa, the increase was 5.5 % and 11.11 %, respectively.And the increase compressive strength for beam filled with normal concrete in the sides was 25 MPa and 20 MPa, the increase was 10.33 % and 4.21 %, respectively, if compared with the control beam.