| Author | Humayan, Iqbal |
| Call Number | AIT Thesis no.ST-90-8 |
| Subject(s) | Concrete beams
|
| Note | A thesis submitted in partial fulfillments of the requirements for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Abstract | Present study aims at investigating the influence of
high fiber volumes on the ultimate in flexure of reinforced
concrete beams. Tests were carried out on isolated simply
supported concrete beams having conventional bar reinforcement with plain and steel fiber concrete. Fibers used were
steel fibers of 30 mm length and 0.5 mm in diameter giving
an aspect ratio of 60. The fiber volumes incorporated ranged
between 2 to 4%. Control specimens were cast to observe the
influence of steel fibers on the behaviour of SFRC in compression and tension.
From the tests for control specimens it was observed
that the compressive strength of SFRC specimens was of the
same order as that of compressive strength of plain concrete of similar mix proportion for fiber volumes as high as
4%. However, it was found that the fiber concrete in compression can develop a higher degree of compressibility and
plastic deformations at failure and thus has higher compressive toughness compared with plain concrete. With the inclusion of fibers post-cracking strength of the composite was
found to increase considerably changing the behaviour of
concrete from that of a brittle material to a ductile one.
Tests results for beams indicated that the increase in the
flexural strength of SFRC beams with conventional bar reinforcement is not substantial for low fiber volumes. But this
increase may be regarded as reasonable for higher fiber
volumes typically about 4% , although it may not be economical . Thus, discrete steel fibers may not be regarded as a
direct replacement of conventional reinforcement as may be
the case with shear strength . However, the inclusion of
fibers in the concrete may be regarded as an added secondary
reinforcement when fibers are primarily incorporated for the
purpose of enhancing the shear strength or when better crack
arrest , control of deflection , and higher flexural and
compressive toughness is desired.
Based on the test results, relationships are proposed
which depict the behaviour of FRC in tension and compression
more accurately. A rational procedure to predict the ultimate flexural strength is suggested. Quite often, not only
the ultimate loads, but yield loads and working loads for
allowable stresses have to computed. The proposed procedure
of analysis can be used to predict the yield load and working loads at intermediate stages as well as the ultimate
strength of the member . The results from the proposed procedure are compared with the observed results and the results
of other researchers, and have found to predict the flexural
strength of SFRC beams with greater accuracy. |
| Year | 1990 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Pama, Ricardo P. |
| Examination Committee(s) | Pichai Nimityongskul ;Ueda, Tamon |
| Scholarship Donor(s) | The Government of Switzerland |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1990 |