Shear Behavior of Reinforced Concrete Inverted-T Deep Beam

Contrary to top-loaded deep beams, Inverted-T (IT) deep beams are loaded on ledges at the beam’s bottom chord. The presence of the load near the bottom of the beams creates a tension field in the web at the loading points. An experimental investigation was carried out in which 8 specimens of reinforced concrete IT deep beams were tested and the effect of the following variables was studied: changing the hanger diameter, hanger arrangement in terms of spacing and distribution distance, hanger reinforcement ratio, vertical and horizontal web shear reinforcement diameter, and spacing. In addition, all the tested beams had long ledges extending to the end of the beam. It was concluded that hanger reinforcement diameter and horizontal web shear reinforcement have an insignificant effect on the IT deep beam capacity. While the change in hanger arrangement, vertical web reinforcement, and ledge length has a significant effect on IT deep beam capacity. The maximum spacing of the hanger reinforcement and the minimum hanger reinforcement ratio passing through the load plate length will be studied in the following publication. A finite element model (FEM) was presented to predict the behavior of IT deep beams. The simulation was carried out using the ABAQUS 2017 software program. The results of the numerical model showed good agreement with the experimental program. Analysis using design codes was checked against the experimental data, where the computed beam capacities were compared to those obtained from the test results. The comparison showed a remarkable difference between the predictions using the design codes and the test results. Computation using design codes significantly underestimated the capacities of the beams. Doi: 10.28991/CEJ-2023-09-05-04 Full Text: PD

Flexural Behavior of One-Way Slabs Reinforced with Welded Wire Mesh under Vertical Loads

This paper aims to study the behavior of one-way concrete solid slabs reinforced with welded wire mesh to investigate the efficiency of using welded wire mesh in the construction of structural slabs as a replacement for ordinary steel bars. This research included experimental and analytical programs. Nine 700×1050 mm one-way simple specimens and six 525×1050 mm continuous one-way slabs with two equal spans were tested under point, line, and uniform static loads. The experimental program studied the use of welded mesh and the number of layers utilized. Numerical analysis was conducted using finite element modeling developed using the ABAQUS 6.13 software package. Experimental and analytical results showed good correlation: the number of layers of welded metal mesh and load type significantly affected the peak vertical load capacity of simple and continuous slabs, with slabs showing higher values with welded mesh than those of ordinary reinforcing bars. In addition, using welded metal mesh to reinforce solid slabs enhanced their cracking behavior as well as their ductility. Doi: 10.28991/CEJ-2022-08-04-03 Full Text: PD

Behavior of high strength concrete columns under eccentric loads

In recent decades, high strength concrete (HSC) has been widely accepted by designers and contractors to be used in concrete structures, especially in high compressive stress elements. The research aims to study the behavior of high strength concrete columns under eccentric compression using experimental and analytical programs. The research is divided into two main parts; the first part is an experimental investigation for ten square columns tested at the Cairo University Concrete Research Laboratory. The main studied parameters were eccentricity of the applied load, column slenderness ratio; and ratios of longitudinal and transverse reinforcement. The second part is analytical analysis using nonlinear finite element program ANSYS11 on nineteen columns (ten tested square columns and nine rectangular section columns) to study the effect of the previous parameters on the column ultimate load, mid-height displacement, and column cracking patterns. The analyzed columns revealed a good agreement with the experimental results with an average difference of 16% and 17% for column ultimate load and mid-height displacement respectively. Results showed an excellent agreement for cracking patterns. Predictions of columns capacities using the interaction diagrams based on ACI 318-08 stress block parameters indicated a safe design procedure of HSC columns under eccentric compression, with ACI 318-08 being more conservative for moderate reinforced HSC columns