Bent up bars | why bent up bars or crank bars are provided in beam and slabs

why bent up bars is provided ? why bent up bars provided in slab ? why bent up bars are provided in beams ? why bent up bars are provided in r.c.c slab ? why crank bars is provided ? why and when bent-up bar[crank] failure of slab reasons In the fixed R.C.C ended Slabs, means column at the ends of the supports. Those slabs faces Two types of moments develop which are called. Positive moment which called (Sagging) develop atmid of the span.Negative moment which called (Hogging) develop at the supports. The continuous beam, over hanging beam, etc. all faces two types of the bending moments positive and negative so to resist these moments is beams and in slabs we provide bars and give a technical names which we discuss in detail below. BENT UP BARS: 1. Bent-up bars or known as Crank bars. Which we provide in the ends on the top of the slab or also in the top of the mid supports (if any type of mid support is present) to counter the negative moment called (Hogging) which produce at that sections of the slabs and beams. 2. Different Angles on the crank bar (Means bends) is provide in the slabs. In some cases we just provide Straight Bars at the end on the top of the slab and in some cases we provide angles on the crank bars which is 45°.  In some cases the 30° bent  is provided when shallow beams are present at the end of the slabs. 3. Normally the length of the crank bar are minimum 300 millimeter and the slope or bend on the crank bars (Bent up bars)  are 1: 10. 4. By providing crank bars in the R.C.C slabs, The Strengthof the slab will be increased very much from those of the slabs in which crank bars are not present. 5. The spacing between the main bars which having a diameter 12 mm or 10 mm should be 6 inches center to center c/c and if you are using 8 mm diameter bars it should be 4 inch center to center c/c. 6. The spacing of distribution bars having diameter 10 mm should be 9 inches to 12 inches center to center c/c. For 8 mm diameter bar 7 inches to 9 inches center to center c/c. The spacing is also depends on the span and thickness of slab but normally we go with this. CONCLUSION: why crank bars are provided in slabs ? To resist Hogging (Negative Bending Moment) at supports.To counter the risk of the failure of the slabs.To encounter the shear force. The shear force is always greater at the sections of supports.By providing crank the strength of slab increased. The crank bars or bent up bar are very important in R.C.C beam or slabs construction because without countering the Hogging (Negative moment) the structure will fail or the strength of the structure will reduced. The hogging bending moment will develop at the supports of the slabs and beams. interview questions for civil engineers interview questions of civil engineering civil engineering interview questions and answers in hindi civil engineering interview questions on buildings civil engineering interview questions and answers civil engineering interview questions in hindi interview questions for civil site engineer all interview questions and answers-civil engineering general civil engineering questions answers How to Provide Crank Bars in Slab Types of load in building /watch/g8sn4HYUVJgUn Wallpaper vs wall paint in hindi /watch/0YHLv6nTvrDTL Minimum height of ceiling /watch/whHBH5FZCqwZB Plinth beam ke saath DPC dena hai ya nahi /watch/ogFDondKBFWKD Thickness of slab in House /watch/4_6X4raOx_eOX Setting time of cement , initial setting time and final setting time /watch/82Q7uEQqG7Jq7 Tiles lagane se seelan ruk jayegi ya nahi /watch/0eBvgEJd6YQdv New plaster pe putty ya paint kitne din baad kare /watch/gjBYoupgEXRgY Source of dampness in wall and building /watch/4zx8jIHhrZTh8 Wooden flooring kaha laga sakte hain kaha nahi /watch/IThzIIU8NHE8z Ghar mein tiles lagwaye ya marble /watch/AKH-3yLlkqFl- Grade of concrete /watch/M1n8vLzAdS3A8 Difference between shuttering , centering and staging of Formwork /watch/wtgLLKM9ZWv9L Difference between one way and two way slab /watch/MF8Gg6OKVyhKG Plaster kaise karte hain aur plaster ke time kya dhyan dena chhaiye ki plaster majboot aur plaster crack free bane /watch/IgFxCPeOUS2Ox Ek room mein kitna tiles lagega aur kitna kharcha aayega /watch/sncqM5gp3W-pq cavity wall kya hota hai ? /watch/8XRcgBGmdcgmc Difference between OPC and PPC cement ? /watch/wxQv-3fDhBQDv Slope of drainage pipe. /watch/smoR4uOPvfOPR Brick test on site. /watch/cTq6CV8IfcoI6 Difference between wall putty and POP. /watch/8YkaVyXTMMCTa plinth beam kya hota hai ? /watch/s8YmD3Kaajlam

Category