5PROBLEM No. 3Draw the Longitudinal section and two cross sections one near the support and other near the mid span of a RCC continuous beam with the following data:Clear span of beams = 3m eachWidth of beam = 200mmOverall depth of beam = 300mmWidth in intermediate supports = 200 mmMain reinforcement = 4 Nos -12 mm diameter bars with 2 bars bent upAnchor/hanger bars= 2-10 mm diameterStirrups = 6 mm 300 mm c/c.Materials : HYSD bars and M20 grade concrete
7PROBLEM No. 4A rectangular beam of cross section 300 x 450 mm is supported on 4 columns which are equally spaced at 3m c/c. The columns are of 300 mm x 300 mm in section. The reinforcement consists of 4 bars of a6 mm diameter (+ve reinforcement) at mid span and 4 bars of 16 mm diameter at all supports (-ve reinforcement). Anchor bars consists of a mm diameter. Stirrups are of 8 mm diameter 2 legged vertical at 200 c/c throughout. Grade of concrete is M20 and type of steel is Fe 415.Draw longitudinal section and important cross sections.
10PROBLEM No. 5Draw to scale of 1:20 the Longitudinal section and two cross- section of a cantilever beam projecting 3.2 from a support using following dataClear span =3.2mOverall depth at free end = 150 mmOverall depth at fixed end = 450 mmWidth of cantilever beam = 300 mmMain steel = 4-28 mm dia with two bars curtailed at 1.5m from supportAnchor bars = 2 Nos. 16 mm diaNominal stirrups = 6mm dia at 40 mm c/cBearing at fixed end = 300 mmUse M20 concrete and Fe 415 steel
12PROBLEM No. 6A cantilever beam with 3.2m length is resting over a masonry wall and supporting a slab over it. Draw to a suitable scale Longitudinal section, two cross-sections and sectional plan with the following data:Size of beam = 300 mm x 350 mm at free end and 300 mm x 450 mm at fixed end and in the wall up to a length of 4.8mMain steel: 4 nos. of 25 mm dia bars, two bars curtailed at 1.2m from free endHanger bars: 2 nos. 16mm.Stirrups: 6mm dia 2 legged 200 mm c/c the support length mm c/c from fixed end up to length of 150mm c/c up to curtailed bars and 200 c/c.Use M20 concrete and Fe 415 steel
15PROBLEM No. 7 A beam has following data Clear span = 4m Support width = 300mmSize of web = 350 x 400Size of flange = 1200 x 120mmMain reinforcement in two layers : tor tor and to be curtailed at a distance 400 mm from inner face of supportHanger bars: torStirrups: 2L c/cUse M20 concrete and Fe 415 steelDraw longitudinal and cross section if the beam isT-beamInverted T-beamL-Beam
18Introduction Used for covering spaces in the form of roof or floor Slab may be supported on walls or beams or columns .Slab supported directly by columns are called flat slabOne Way SlabTwo Way SlabDr.G.S.Suresh
19Introduction Slabs could be simply supported, continuous or cantilever In two way slab the corners may be held down by restraints or may be allowed to lift upAdditional torsion reinforcement is required at corners when it is restrained against uplifting as shown in FigDr.G.S.Suresh
21IntroductionThickness of the slab is decided based on span to depth ratio specified in IS Min reinforcement is 0.12% for HYSD bars and % for mild steel bars.The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slabMaximum spacing of main bar is restricted to 3 times effective depth or 300 mm which ever is lessFor distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm which ever is lessDr.G.S.Suresh
22IntroductionGenerally 15 mm to 20 mm cover is provided for the main reinforcementsAlternate main bars can be cranked near support or could be bent at 1800 at the edge and then extended at the top inside the slab as shown in FigCurtailment and cranking of bars and is shown in FigDr.G.S.Suresh
29PROBLEMPrepare a detailed structural drawing of one way continuous slab for a hall of clear dimensions 7m wide and m long, use following dataCentre to centre distance of supporting beams = 3.0 mSpan of the beams = 7.23mBeams are supported on walls of 0.23 m thicknessC/s of beam = 230 x 450 mmGrade of concrete : M20Type of steel : Fe415Clear cover : 20 mmSlab thickness: 150 mmBeam depth is inclusive of slab depth, The hall is having walls on all 4 sides
30PROBLEMMain positive end span = 8mm c/cMain reinforcement in other interior panels = 8 mm 200 c/cNegative all supports = 8mm diameter @ 200 c/cDistribution steel= 8mm 200 c/c
38Do it Yourself1. Draw the longitudinal section and typical cross sections ( at centre and support), and show the reinforcement details in a simply supported rectangular beam of size 300 mm x 500 mm, clear span 5m supported on walls of 0.3m, use a suitable scaleReinforcements:Main: 4 No. 16mm dia with 2 No. cranked at 1m from centre of support. Stirrup holders 2 Nos. of 12 mm diaStirrups: 2 legged 8 mm dia stirrups at 250 mm c/c in the central 2m span and 2 legged 8 mm dia stirrups at 150 mm c/c in the remaining portion. Assume concrete M 20 grade and steel Fe 415, and suitable cover. Prepare the bar bending schedule and calculate quantity of steel and concrete required.
39Do it Yourself2. Prepare the bar bending schedule and estimate quantity of steel and concrete after drawing the longitudinal and cross section. Other details areSpan of beam = 4.2 mCross section at support end 300 x 600 mm and cross section at free end 300 x 150 mmReinforcements:Main tension steel: 4-20 mm dia, 2 bars are curtailed at a distance of 2m from free endHanger bars: 1-12 mm diaTwo legged stirrups 8mm 140 mm c/c for full length.
40GOOD DAY Dr. G.S.Suresh Civil Engineering Department The National Institute of EngineeringMysoreMob: