Effect of shape of main reinforcement in slabs
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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.
Effect of shape of main reinforcement in slabs
- 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) ISSN 0976 – 6308 (Print) ISSN 0976 – 6316(Online) Volume 5, Issue 8, August (2014), pp. 01-03 © IAEME: www.iaeme.com/ijciet.asp Journal Impact Factor (2014): 7.9290 (Calculated by GISI) www.jifactor.com 1 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 3 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.