Design of Self supporting Steel Chimney for

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1 Prepared by : Date : Job No. : Sheet : Cont'd : Verified by : Project : Subject : Calculation Sheet CALCULATION Revision Notes : Design of Self supporting Steel Chimney for Data Wind Loads as per India Standards. Height of Steel Chimney. m Outside Diameter at Top. m Intensity of Wind Pressure upto a height of m as per Is 7. kn/m Note : Enter Data in Cells marked this only Recommended height of Flared Portion = H/.7 m Adopt height of Flared Portion. m Minimum outside diameter of flared chimney at base =.*Dtop. m Consider outside diameter of the chimney at base dbase := Shape factor of Steel chimney circullar in plan.. m.7 Yeild stress of Chimney Steel as per IS - fy = mpa Temperature of Steel Chimney C Temperature Coefficient Kt. External corrosion allowance Tce mm (ref.table- ; IS- part-:99 for non-copper bearing steel and design life years) mm Internal corrosion allowance Tci mm (ref.table- ; IS- part-:99 for non-copper bearing steel and design life years) mm Minimum thickness of the shell without corrosion = Tmin = dtop/ mm Consider a shell thickness = TtopA mm Ttop = TtopA + Tce + Tci = + + = mm Thickness of Brick Lining mm Unit wt of Brick lining efficiency of joint on tension side η t = efficiency of joint on tension side ηc = Load Combinations (a) Dead load+ Wind load. kn/m Steel density 7. kn/m Allowable tensile stress in steel plate as per IS -7 =.*fy*kt*ηt = mpa E = Youngs modulus of Elasticity of steel Reference: clauses., IS (Part-):99 (b) Dead load+ Load due to lining+ Imposed load on service platforms + Wind load : Forces acting on Steel Chimney : ρ = density of steel = 7. kn/m ) Self weight of chimney. Weight of the (platform+ access ladder+ helical strake+ rain cap + Written and programmed etc) is assumed by to be % of the self weight of chimney shell. Ws = ρ. (π d). (t).(h) Ws = Ws (tension) Ws =.. Ws (compression) ) Weight of Lining. ρ = density of lining =.7. mpa Visit Abqconsultants.com This program Designs and Optimises Steel Chimney and the RCC Foundation. :- A B Quadri abquadri@yahoo.com abquadri@gmail.com kn/m Ws = ρ. (π d). (t).(h) t = thickness of lining =. mm Prep By : A B Quadri- Abq Consultants em-abquadri@yahoo.com---/ Royal Residency, Besides Amba talkies, Mehdipatnam, Hyderabad--

2 999 Wind Pressure, Moment and Shear from Top at every Segment Nos of horizontal Segments chimney divided into = Each Segment depth. m. Height from Wind diameter effective D = Force on each ground bottom of each Pressure D*.7 segment bottom of each 9. segment cg segment. s.no m kn/m m D*S.f Kn Kn Kn.m Wind pressure diagram Height in meters..... Wind pressure KN/m Wind force 9. Moment Diagram 9. Shear Diagram Moment Diagram. Shear Diagram.. Height in meters.. Height in meters Moment in Kn.m -. Shear Force in KN Prep By : A B Quadri- Abq Consultants em-abquadri@yahoo.com---/ Royal Residency, Besides Amba talkies, Mehdipatnam, Hyderabad--

3 : Thickness of Chimney Plate without corrosion allowance : s.no Height from top diameter of chimney from top Thickness of Steel Plate without corrosion D/t ratio Effective height for axial stress h ratio h/d for axial stress ratio h/d for bending stress =.*h/d Allowable stress in axial compression as per table * kt Allowable stress in bending as per table * kt Section Modulus Z =.77 d t Self wt Ws from top Wt of Lining from top m mm mm mm m Kn Kn Prep By : A B Quadri- Abq Consultants em-abquadri@yahoo.com---/ Royal Residency, Besides Amba talkies, Mehdipatnam, Hyderabad--

4 s.no Height from top Compressive stress in steel due to Self wt Compressive stress in steel due to Lining wt tensile and compreeive stress due to wind. Windward side tensile stress in steel due to (Wind + Self wt of Chimney.) Leeward side compressive stress in steel due to (Wind + Self wt of Chimney.) Windward side tensile stress in steel due to (Total dead load =.*Ws) + wt of lining - Wind Leeward side compressive stress in steel due to (Total dead load =.*Ws) + wt of lining + Wind Total thickness of Steel plate required with internal and external corrosion = SW total Thickness check m mm Prep By : A B Quadri- Abq Consultants em-abquadri@yahoo.com---/ Royal Residency, Besides Amba talkies, Mehdipatnam, Hyderabad--

5 Check total thickness of Chimney with corrosion allowance : s.no Height from top diamete Total thickness r of of Steel chimne Plate with corrosion y from allowance. top D/t ratio Effective height for axial stress-- h ratio h/d for axial stress ratio h/d for bending stress =.*h/d Allowable stress in axial compression as per table * kt Allowable stress in bending as per table * kt Section Modulus Z =.77 d t Self wt Ws Wt of Lining (total) from from top top m mm mm mm m Kn Kn Prep By : A B Quadri- Abq Consultants em-abquadri@yahoo.com---/ Royal Residency, Besides Amba talkies, Mehdipatnam, Hyderabad--

6 s.no Height from top Compressiv e stress in steel due to Self wt (total). Compressiv e stress in steel due to Lining wt tensile and compreeive stress due to wind. Windward side tensile stress in steel due to (Wind + Self wt of Chimney.) Leeward side compressive stress in steel due to (Wind + Self wt of Chimney.) Windward side tensile stress in steel due to (Total dead load =.*Ws) + wt of lining - Wind Leeward side compressive stress in steel due to (Total dead load =.*Ws) + wt of lining + Wind 7 9 m Prep By : A B Quadri- Abq Consultants em-abquadri@yahoo.com---/ Royal Residency, Besides Amba talkies, Mehdipatnam, Hyderabad--

7 :- Design of Anchor Bolts (Holding Down Bolts) :- mm dia Maximum tensile force per unit length of circumferance =. *. = 7 n/mm nos Provide M mm dia Anchor bolt Area at root of threads = Allowable Stress in Anchor bolt = mm Strength of Anchor Bolt = * =. Kn Spacing of Bolt =. * = 9 mm 7 d = mm Provide Anchor Bolt at 9 mm spacing Nos of Anchor Bolts Required = nos Spacing of Bolt provided = mm 9 :- Design of Base Plate :- Maximum stress on Chimney base plate due to Load case to =. *. = 9 n/mm Allowable Bearing Stress for Steel on Concrete =. Width of base Plate required = 9 = mm dia. Allowable stress in bending of Base Plate =.7 fy A A =.7 * = 7. n/mm Moment on mm wide plate =. * * 9 * 9 thk base pl =. Kn.m 9 Z of plate = * t^ [ 7. ] Sect A-A.: t = * * ½ = thickness of base plate. * =. mm Adopt t = mm thk thk 9 :- Design of Vertical Stiffner Plate :- mm Axial load on stiffner = Tensile load on one bolt = Fa = Effective length of stiffner =. * = mm Assume thickness of stiffner, including external Width of stiffner = 9 mm corrosion allowance = mm Net thickness of stiffner = mm r =. mm L/r = =.7 fcc = π² E = 9.7 *. Allowable stress in compression σac =.7 mpa = Allowable Load = σac x A =.7 * 9 * = kn >= kn.: Provide Vertical stiffner Plate = mm thick. Kn (l/r)² mpa Prep By : A B Quadri- Abq Consultants em-abquadri@yahoo.com---/ Royal Residency, Besides Amba talkies, Mehdipatnam, Hyderabad--

8 :- Deflection of Chimney :- s.no Height from top diamete r of chimne y from top Assumed thickness of Steel Plate without corrosion Moment of Inertia I (m) Wind Moment at bottom of each segment. M/EI Area M/EI Moment of (Area M/EI) from top deflection mm height to deflecti on ratio (h/δ) check less than H/ 9. m mm mm m Kn.m /mm mm mm mm....e+.e+.e E-9.E-.E E-9 7.E-9.E-.E-.9E-.E E-.E-.E E-.E- 7.9E E- 7.E-.E E- 9.E-.E E-.E-.7E E-.E-.7E+...7.E-.E-.E E-.E- 7.9E-.E- 9.E- 9.77E-.E-.E-.E-.9E-.E-.7E-.E+ 7.77E+ 9.E+.E+.E+.E Deflection Diagram E-7.E-.7E E-7.E-.9E E-.E-.9E E-.9E-.E E-.E-.7E E-.9E-.E E-.9E-.E E-.E-.E E-.7E-.7E+. Maximum deflection at top = mm Height to deflection ratio (h/δ) at top = = <= h = mm Prep By : A B Quadri- Abq Consultants em-abquadri@yahoo.com---/ Royal Residency, Besides Amba talkies, Mehdipatnam, Hyderabad--

9 :- Design of Chimney Foundation :- Loads on Foundation :- Grade of conc () modular ratio m.7..9 Allowable compressive stress (Direct)... M Grade of Steel () 9.. Allowable compressive stress (Bending) Allowable tebsile stress (Direct) Allowable tebsile stress SBC of Soil At foundation Base kn/m² Depth of foundation from NGL. m Concrete density kn/m Self Weight of Chimney without corrosion allowance Sw = Self Weight of Chimney with corrosion allowance Self Weight of Chimney Lining. Weight of the (platform+ access ladder+ helical strake+ rain cap + etc) is assumed to be % of the self weight of chimney shell without corrosion allowance Weight of the (platform+ access ladder+ helical strake+ rain cap + etc) is assumed to be % of the self weight of chimney shell with corrosion allowance Moment at foundation top due to wind load Sw Shear at foundation top due to wind load Swl 7 Kn Moment due to wind shear at foundation base Mswl = 7 Kn.m SL Mwl = 9 Kn Kn 7 Kn = Swp = 79 Kn Swp = Kn 77 As bd Permissible Shear Stress in Concrete Tc for grade of concrete = Kn.m = Adopt the diameter of Chimney foundation D =. m Adopt the thickness of Chimney foundation T = mm Self wt of Footing Swf = 77 kn Area = π D² =. Load Combinations Reference: clauses., IS (Part-):99 (a) Dead load+ Wind load Z = π D³ = 9. (b) Dead load+ Load due to lining+ Imposed load on service platforms + Wind load m² m² s.no Load case Dl+Wl Sw+swf+Mwl+Ms wl DL (Axial) Kn WL (Moment) Kn.m DL/A + MWL/Z kn/m DL/A - MWL/Z kn/m eccentricity < D/, no uplift m F.S due to over turning check Dl+Wl Sw+swp+SL+swf +Mwl+Mswl Dl+Wl Sw+swf+Mwl+Ms wl Dl+Wl Sw+swp+SL+swf +Mwl+Mswl Prep By : A B Quadri- Abq Consultants em-abquadri@yahoo.com---/ Royal Residency, Besides Amba talkies, Mehdipatnam, Hyderabad--

10 e Design of Footing slab Data FFL H P Concrete Grade fc' = Reinforcement Steel Grade fy = A FGL S.B.C of Soil Qs = Kn/m Soil filling inside Outer dia of chimney base plate d =. m Dia of Footing OD =. m A = mm Level of footing below ground Totd = mm D Depth of Soil D = mm Totd Depth of Footing T = mm Footing Reinforcement dia Φ = mm Reinforcement cover c = 7 mm T Actual Loading Pattern. d OD σ = P' ± A M' Zxx OD Assume initially Layer of mm Φ bars nos spaced radially along the circumferance. + mm Φ bars As = 9 mm Spacing between bars at Φ =. º =.9 radians end. = 799 Radius of Chimney = ro = mm Radius of Foundation = fro = mm = Bar Spacing at ro = mm Length of segment 'PQ' <= Bar Spacing at fro = mm Length of segment 'RS' Net Uniform pressure = 7. Kn / m under area 'PQRS' Pressure due to = 7. Kn / m Moment at 'RS' Pressure due to =. Kn / m Moment at 'PQ' Area of Segment 'PQRS' =. m CG of Segment 'PQRS' =. m from 'PQ' fro A ro rs b a P Φ rp Q R a b Main Reinforcement S Area covered by one unit of main reinforcement. Critical Section for Moment Footing Outer Dia A Chimney Outer dia of base plate Width of segment RS Width of segment PQ = = mm mm Line of Punching Shear Line of Shear fig 9 Prep By : A B Quadri- Abq Consultants em-abquadri@yahoo.com---/ Royal Residency, Besides Amba talkies, Mehdipatnam, Hyderabad--

11 C / L of foundation Section A - A fig Straight portion Sloping portion r Φ top radial reinforcement. Shear Stirrups Not Required Main Radial reinforcement Circullar reinf Φ nos c/c 9 7 cover critical punching shear section C / L 7 critical shear Section.: Moment at 'PQ' Mf = =.9 Kn.m fy =.: k =.9 *. =.9 fyall =.9 *. + fc' = j = - k = -.9 =.9 fc'all = m = R = fc'all j k = *. *.9 *.9 =.9..9 Hence d = Mf =.9 * = mm volume of footing b * R *.9 =. m +.79 m.: adopt T = mm cover = 7 mm d = m.: d = 7 mm effective depth +.7 m As = M = 9 = mm = 7. m Fyall * j * d *.9 * 7 Wt of Footing Minimum As required = 7 mm >= mm.: Adopt As = 7 mm = 77 kn.: Provide Φ + Φ AΦ = Π * ( ² + ² ) Net Wt of Footing dia bars. = kn layer of Main radial reinforcement = 9 mm > 7 mm ok Provide c/c p% = 9 * =.7 % distribution steel * 7 Punching Shear : Check Punching shear at ro + d/ from the c/l r = mm d = 7. mm r + d = 9 mm Φ =. º =.9 radians Radius of Punching shear = rps = 9 mm Radius of Foundation = fro = mm Bar Spacing at rps = mm Length of segment 'aa' Bar Spacing at fro = mm Length of segment 'RS' Net Uniform pressure = 7. Kn / m Area of Segment 'PQaa' =.9 m under area 'PQRS' CG of Segment 'PQaa' =. m Pressure due to = 7. from 'aa' Kn / m Moment at 'RS' Pressure due to =. Kn / m Moment at 'PQ'.: Punching Shear at 'aa' F = = 9.7 Kn Allowable Punching Shear stress =. fck =. * =..: Depth required for punching shear do F 97 = =. fck *. * = < 7 mm provided OK Prep By : A B Quadri- Abq Consultants em-abquadri@yahoo.com---/ Royal Residency, Besides Amba talkies, Mehdipatnam, Hyderabad--

12 Shear : Check shear at r + d from the c/l, End of Straight portion, and at three points at sloping portion. distance from c/l mm 9 7 Reinforcement Spacing mm Effective depth mm Bar dia mm As mm 9 9 p% Net Uniform pressure kn/m Pressure due to rs kn/m Pressure due to moment at section kn/m Area of Segment 'PQxx' m CG of Segment 'PQxx' m M actual / bar Kn.m M allowable / bar Kn.m 9 p% for Shear Shear Stress tc... Shear allowable Kn 9 Shear actual Kn Shear Reinf Not Reqd Not Reqd Not Reqd Shear - Vs per main bar Kn Shear - MS bar dia fyall spacing mm Minimum shear s =.Asvfy/b mm.: Provided spacing = mm Prep By : A B Quadri- Abq Consultants em-abquadri@yahoo.com---/ Royal Residency, Besides Amba talkies, Mehdipatnam, Hyderabad--