Membrane action in orthotropic ally reinforced concrete recta-ngubr slabs

Dissertant

Abd al-Razzaq, Walid Khalid

University

University of Technology

Faculty

-

Department

Department of Building and Construction Engineering

University Country

Iraq

Degree

Master

Degree Date

2006

English Abstract

The majority of the previous works on the subject of membrane action in R.C.

rectangular slabs have considered the slab to be isotropic ally reinforced in the two orthogonal directions and equal amounts of reinforcement have been assumed to exist at negative and positive bending moment regions.

The main reason for such consideration was to simplify the method for the membrane analysis and to reduce the number of involved parameters.

However, in order to evaluate the actual effect of membrane action in R.C.

Two-way rectangular slabs, the practical case of orthotropic reinforcement is essentially required to be taken into account.

The present research includes this important parameter and therefore it is aimed from the present work to furnish a rigorous rigid-plastic analysis of membrane action in orthotropic ally reinforced concrete rectangular slabs having two parallel edges clamped against rotation and horizontal translation while the other two edges are simply supported , and the slab is subjected to uniformly distributed load.

Two cases are investigated depending on whether the clamped edges are the long or the short edges.

Based on the simple yield line theory, the correct mode of failure and the associated collapse uniform load are first determined for these two slab cases.

Then by adopting the pattern of failure predicted by the yield line theory, an upper bound rigid-plastic solution is presented for each slab case that takes into account the significant effects of membrane forces inducing in the plane of the slab with continuing deflection.

Therefore these solutions describe the load–deflection behavior of such slabs under the combined effect of bending and membrane action.

The load-deflection behavior of a specified reinforced concrete slab has been found to be largely affected by many parameters including the slab rectangularity ratio (m), steel ratio (p), concrete strength (fb), and yield stress of steel (Jy) and coefficient of orthotropic (X).

The slab is found to carry loads far beyond those predicted by Johansen's simple yield line theory and this enhancement in load is greater for a slab with lower values of (aw) , (p),( a), and (fy) and higher value of (ft).

A theoretical studies of maximum yield load reveals a promising saving in reinforcement by using stronger concrete.

For rectangular slabs having their two long edges clamped against rotation while the other two edges are simply supported, such saving in reinforcement could be as high as (45 %) if the slab is lightly loaded, and (20 %) for a slab under moderate load.

While in rectangular slabs having their two short edges clamped against rotation while the other two edges are simply supported, such saving in reinforcement could be as high as (40 %) if the slab is lightly loaded, and (17 %) for a slab under moderate load.

Main Subjects

Civil Engineering

Topics

• Mechanical properties
• Reinforced concrete

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-305896