This document discusses the effect of using alternative shapes for main reinforcement in concrete slabs. Specifically, it examines using rectangular trough, trapezoidal trough, or V-shaped reinforcement rather than the typical horizontal reinforcement. Using alternative shapes could increase the moment-carrying and shear-carrying capacity of slabs while reducing deflection. This is due to the slab acting as a folded plate up to a certain limit because of the reinforcement shape. The document also discusses using this concept with ferrocement slabs to further increase strength with reduced dead load. In conclusion, reinforcement shape affects structural behavior and alternative shapes may provide design and structural benefits over conventional horizontal reinforcement.

1. INTERNATIONAL JOURNAL OF CIVIL ENGINEERING
International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online), Volume 5, Issue 8, August (2014), pp. 01-03 © IAEME
AND TECHNOLOGY (IJCIET)
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ISSN 0976 – 6316(Online)
Volume 5, Issue 8, August (2014), pp. 01-03
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IJCIET
©IAEME
EFFECT OF SHAPE OF MAIN REINFORCEMENT
IN SLABS
SIDRAMAPPA SHIVASHANKAR DHARANE
SVERI’s College of Engineering Pandharpur,
Maharashtra, India
ABSTRACT
In civil engineering design and construction the main steel in beams and slabs are used to
take the tension and to increase the ductile behavior. In slabs the main and distribution steel is
provided in horizontal form. Also the main steel in singly reinforced and doubly reinforced beams is
in horizontal form only. But if we replace this horizontal form of the reinforcement in beams and
slabs by rectangular trough, trapezoidal trough or V shaped, there will be increase in the moment
carrying, shear carrying capacity with reduced deflection because of folded plate action and thereby
the sections becomes more economical.
Keywords: Folded Plate, Beams, Slabs, Main Reinforcement, Rectangular Trough/ V Shaped Bars
and Ductility.
INTRODUCTION
In civil engineering design and construction steel reinforcements are used to take mainly
tension and increase ductility of the members such as beams, slabs, footing, etc. In case of doubly
reinforced beams and columns the steel is also used to take compressive force along with increasing
its ductility. The main steel used in slabs is in horizontal form.
In case of slabs especially continuous slab the steel is provided on tension side only. But if
we consider the critical loading as per substitute frame method the negative bending moment also
exists in middle of span, so it is necessary to provide the steel at top and bottom side of the slab in
middle of span. Generally it is avoided from economical point of view. But because of this there will
be small hair cracks at top of the slab and corrosion of steel may take place. To avoid this steel
should be provided on top as well bottom side of the slab.

2. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online), Volume 5, Issue 8, August (2014), pp. 01-03 © IAEME
2
So instead of providing separately steel at top and bottom side of the slab if the steel is
provided in the form of alternate rectangular trough, trapezoidal trough or V shaped main and
distribution steel the slab will also act as a folded plate up certain limit. Because of the action of
folded plate in addition to bending and shear the load carrying capacity of the slab will also increase
with reduced deflection. This type of arrangement of providing steel will lead to economical design
though the design is very complicated.
The strength of these slabs will be further increased by using the concept of ferrocement. In
ferrocement slabs the two wire meshes may be used at top and bottom each along with skeletal steel.
The skeletal steel can be used in the same form as rectangular trough or V shaped bars along both the
sides of the slab. In ferrocement the dead load will be reduced considerably. To avoid the
compaction problem the self-compacting admixtures can also be used to make the matrix self-compactable.
This new concept of providing the steel in the form of rectangular or V shaped leads to
increase the load carrying capacity with reduced deflection and increase in ductile behavior.
SALIENT FEATURES AND CONCLUSIONS
1. Critical loading conditions will be considered in design as per substitute frame method.
2. The slab thicknesses will reduce considerably and thereby self-weight of slabs will reduce.
3. Load carrying capacity will increase for same area of steel and concrete used in the
conventional design of slabs because of additional folded plate action.
4. The further strength can be increased by using additional wire meshes i.e. the concept of
ferrocement with reduced dead load.
5. This type of ferrocement flat slab can also be used for the intermediate floors.
REFERENCES
1. Sidramappa Dharane and Archita Malge, “Experimental Performance of Flexural Behavior of
Ferrocement Slab Under Cyclic Loading”, “International Journal of Civil Engineering and
Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online), Volume 5,
Issue 3, March (2014), pp. 77-82.
2. Dharane Sidramappa Shivashankar and Patil Raobahdur Yashwant, “Design and Practical
Limitations in Earthquake Resistant Structures and Feedback”, International Journal of Civil
Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online),
Volume 5, Issue 6, June (2014), pp. 89-93.
3. Dharane Sidramappa Shivashaankar and Patil Raobahdur Yashwant, “By Adjustable Capacity
of Pump 24 X 7 Water Supply by using Existing Resources”, International Journal of Civil
Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online),
Volume 5, Issue 6, June (2014), pp. 87 - 88.
4. Dharane Sidramappa Shivashaankar and Patil Raobahdur Yashwant, “Earthquake Resistant
High Rise Buildings –New Concept”, International Journal of Advanced Research in
Engineering Technology (IJARET), ISSN 0976 - 6480 (Print), ISSN 0976 - 6499 (Online),
Volume 5, Issue 6, June (2014), pp. 121 - 124

3. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online), Volume 5, Issue 8, August (2014), pp. 01-03 © IAEME
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5. Mohammed S. Al-Ansari, “Flexural Safety Cost of Optimized Reinforced Concrete Slabs”,
International Journal of Advanced Research in Engineering Technology (IJARET),
ISSN 0976 - 6480 (Print), ISSN 0976 - 6499 (Online), Volume 3, Issue 2, July (2012),
pp. 289 - 310.
6. S.R.Debbarma and S.Saha, “An Experimental Study On Growth Of Time-Dependent Strain In
Shape Memory Alloy Reinforced Concrete Beams And Slabs”, International Journal of Civil
Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online),
Volume 3, Issue 2, July (2012), pp. 108 - 122.
7. Dharane Sidramappa Shivashaankar and Patil Raobahdur Yashwant, “Role of Ferrocement
Cavity Wall in Earthquake Resistant Structure and Construction Method”, International Journal
of Advanced Research in Engineering Technology (IJARET), ISSN 0976 - 6480 (Print),
ISSN 0976 - 6499 (Online), Volume 5, Issue 6, June (2014), pp. 108 - 111.