Analysis of reinforced concrete beams with large opening

Dissertant

Muhammad, Thair Jasim

University

University of Technology

Faculty

-

Department

Department of Building and Construction Engineering

University Country

Iraq

Degree

Master

Degree Date

2004

English Abstract

This study is devoted to investigate the behavior of reinforced concrete beams with large openings subjected to pure torsion, using a non-linear three- dimensional finite clement model.

The 20-node isoparametric brick elements have been used to model the concrete The reinforcing bars are idealized as axial member, embedded within the concrete element and perfect bond between the concrete and the reinforcement has been assumed to occur.

The behavior of concrete in compression is simulated by an elasto-plastic work hardening model followed by a perfectly plastic response, which is terminated at the onset of crushing.

In tension, , smeared crack model with fixed orthogonal cracks has been used with the inclusion of models for the retained post-cracking tensile stress and the reduced shear modulus. The non-linear equations of equilibrium have been solved using an incrementa-iterative technique operating under load control The solution algorithm used was the modified Newton-Raphson method.

The numerical migration has been conducted using the 27 point Gaussian type rule. Different type of reinforced concrete beams with large rectangular transverse openings have been analysed and the finite element solution were compared with the experimental data Several parametnc studies have been carried out to investigate the effect of some important finite element and material parameters The effect of mesh refinement, concrete compressive strength, amount of transverse reinforcement, warping restraint and opening size on the torque-twist response have been investigated.

In general good agreement between the finite element solutions and the experimental results has been obtained.

The finite element solutions revealed that the collapse torque and post-cracking tensional stiffness decrease with the increase of length or depth of opening. for the beam tested in this study, the result show that the ultimate torque capacity increases by about 21% when the length of opening decreases form 800mm to 400mm, and it decreases by 16% when the length of opening increases from 800mm to 1600mm Also , as the depth of the opening decrease, form 200mm to 180mm, the torsional capacity increases by about 15%, and it decreases by 16 % when the depth of opening increases from 200mm to 240mm

Main Subjects

Civil Engineering

Topics

• Mechanical properties

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-305926