Behavior of porcelanite reinforced concrete deep beams

Dissertant

al-Bayati, Nabil Abd al-Majid Jaddu

Thesis advisor

Sarsam, Qays Fuad
al-Shaarbaf, Ihsan Ali Saib

University

University of Technology

Faculty

-

Department

Department of Building and Construction Engineering

University Country

Iraq

Degree

Ph.D.

Degree Date

2012

English Abstract

This work is devoted to study the behavior of simply supported reinforced concrete deep beams constructed with Porcelanite lightweight aggregate.

The experimental program consists of two parts; the first part is primarily concerned with investigating the properties of materials to be used and testing 75 specimens (45 cylinders, 15 cubes and 15 prisms) according to ASTM for determining the quality limits of concrete.

The second part of the experimental program consists of casting and testing 16 reinforced concrete deep beams loaded under two symmetrical point loads.

The test beams had the same overall span of 1400mm, constant cross section 150mm wide and 400mm overall depth, and reinforced with the same amount of main tension bars (3f16).

Studies were performed on testing deep beams by classifying specimens into five categories, first group to study the influence of concrete compressive strength f'c (f'c = 17.5, 18.8, 22.1, 27.1 and 30.8MPa), second group to study shear-span/effective depth (a/d) ratios effects (a/d = 1, 1.2 and 1.4), third group to investigate the effect of vertical web reinforcement (rv = 0.00, 0.29, 0.43, 0.61 and 0.86%), fourth group to study the effect of horizontal web reinforcement (rvh = 0.00, 0.29, 0.43, 0.61 and 0.86%) and final group to study the influence of both vertical and horizontal web reinforcement, one or both of them.

Several measurements were made during each beam test, these included: midspan vertical defections, support horizontal displacement, concrete surface strains at different locations, flexural and inclined cracking shear loads and ultimate failure load.

The crack patterns were also marked and important observations were noted.

The analysis of results obtained from the tests of deep beams demonstrates that when f'c is increased by about 76%, the ultimate loads are also increased by 63% while the midspan vertical deflection decreased by 37%.

Increasing a/d ratios from 1.0 to 1.4 showed a reduction in ultimate strength by about 10% and increased midspan vertical deflection by 32%.

The results of analysis show clearly that the vertical web reinforcements have significant effects on the ultimate strength greater than horizontal web reinforcements.

Increasing rv% from 0.00 to 0.86 leads to increased ultimate strength by about 75% and decreased midspan vertical deflection by 36%.

In contrast, increasing rvh% from 0.00 to 0.86 leads to increased ultimate strength by only 26% and decreased midspan vertical deflection by 32%.

A computer software package is created to analyze reinforced concrete deep beams based on the Strut-and-Tie Model (STM) adopted by ACI 318M-11code.

A method of analysis for predicting ultimate shear strength of deep beams made with different concrete densities, sand lightweight aggregate concrete (SLWAC) and normalweight aggregate concrete (NWAC) is put forward.

The proposed method was applied to deep beams tested in the present study and also to experimental data reported by other investigators.

Good agreement between the proposed analysis and the test results was found (coefficient of variation, COV of only 9%).

The methods of analysis currently available on the subject were thoroughly examined.

These methods were applied to the tested beams and the results were compared.

A three-dimensional finite element model is adopted to examine the structural behavior of Porcelanite reinforced concrete deep beams.

Nonlinear finite element analysis is performed using finite element program (ANSYS 2012-Version 14).

Finally, it is found that the maximum shear capacity of Porcelanite reinforced concrete deep beams that were calculated by using design equations of (Strut-and Tie Model) based on ACI 318M-11 code were conservative where that ratio of experimental strength is on average 56.8% greater than that predicted by the code.

Main Subjects

Engineering & Technology Sciences (Multidisciplinary)

Topics

• Building materials
• Concrete
• Reinforced concrete

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-420212