Wind effect on Hyperbolic RCC Cooling Tower

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1 Iteratioal Joural of Curret Egieerig ad Techology E-ISSN 77 46, P-ISSN 47 6 INPRESSCO, All Rights Reserved Available at Research Article Wid effect o Hyperbolic RCC Tower Priya Kulkari * ad S. K. Kulkari Civil Egieerig Departmet, Walchad Istitute of Techology, Solapur, Maharashtra, Idia Accepted Nov, Available olie Nov, Vol., No.6 (Dec ) Abstract R/C coolig towers are used for may kids of idustrial ad power plats. These are huge structures ad also show thi shell structures. The preset paper deals with effect of wid aalysis of hyperbolic coolig towers havig variatio i the height ad thickess. The existig coolig towers are chose from Bellary thermal Power statio (BTPS) as case study. For the other models of coolig towers, the dimesios ad thickess of the shell are varied with respect to referece tower. The coolig towers are aalyed by Staad. ProV8i havig boudary coditios cosidered are Top ed free ad Bottom ed is fixed. The Material properties of the coolig towers are youg s modulus. Mpa, Poisso Ratio. ad desity of RCC kn/m. Wid loads o these coolig towers have bee calculated i the form of pressure by usig desig wid pressure co efficiet give i IS 4-98 code & desig wid pressure at differet levels as per IS 87 (Part )-987 code. Displacemet i X, Y ad Z directios, maximum ad miimum pricipal stress at top ad bottom are obtaied. The variatio i displacemet v/s thickess, maximum ad miimum pricipal stress is plotted graphically. Keywords: tower, Displacemet, Pricipal Stress, ad Wid Load.. Itroductio Wid forms the major exteral applied loadig i the desig of coolig tower ad it also provides the most commo meas of determiig degree of lateral stregth required by towers. towers costitute very importat Structure i the power geeratio systems they also cotribute to eviromet protectio. The hyperbolic coolig towers are used i uclear power plats, thermal power plats, chemical ad other idustrial plats. From the structural poit of view they are high rise reiforced cocrete structures i the form of doubly curved thi walled shells of complex geometry ad so is their aalysis ad desig. The i-plae membrae actios primarily resist the applied forces ad bedig plays the secodary role i these special structures. I the absece of earthquake loadig, wid costitutes the mai loadig for the desig of atural draught coolig towers. The static ad dyamic aalysis of hyperbolic coolig tower. The study icludes the compariso betwee two existig coolig towers of differet elemet types ad varyig mesh ratio is adopted ad also deflectio patter, maximum pricipal stresses ad vo mises stress is compared i the aalysis (Sachi Kulkari ad Prof A. V. Kulkari, 4). The effect of wid loadig o aalysis of atural draught hyperbolic coolig tower emphasie o effect of wid *Correspodig author: Priya Kulkari o Natural draught hyperbolic coolig tower. The slederess of the colums ad the large dimesios of the shell make these structures vulerable to earthquake ad wid disturbaces (Tejas G. Gaikwad et al, 4). Respose of Natural Draught Towers to Wid loads. This paper deals with the study of five coolig towers of m, 77m, ad m, high above groud level with differet throat height to total height ratio s, throat diameter to base diameter ratio s ad diameter to thickess ratio s. The results of the aalysis iclude membrae forces, meridioal force ad hoop force ad bedig momets (G. Murali, ). Fiite Elemet Aalysis for Structural Respose of RCC Tower Shell Cosiderig alterative supportig systems. The compariso has bee made of the self-weight loadig, static wid loadig ad pseudo static seismic activities the loads are calculated as per the recommedatio of relevat IS codes (Esmaeil Asadadeh et al, ).. Geometry of Towers The geometry of the Hyperboloid revolutio Iteratioal Joural of Curret Egieerig ad Techology, Vol., No.6 (Dec ) () I which is the horiotal radius at ay vertical coordiate, Y with the origi of coordiates beig defied by the ceter of the tower throat, is the radius of the throat, ad b is some characteristic dimesio of the hyperboloid.

Priya Kulkari et al Wid effect o Hyperbolic RCC Tower Fig. Nodes, Meshig ad Boudary Coditios (Bottom View) Fig. Geometry of existig Tower Table represets geometric details of the coolig towers i.e. total height, diameters at various levels etc.

2 Priya Kulkari et al Wid effect o Hyperbolic RCC Tower Fig. Nodes, Meshig ad Boudary Coditios (Bottom View) Fig. Geometry of existig Tower Table represets geometric details of the coolig towers i.e. total height, diameters at various levels etc. S. No Table Geometric Details of Towers Descriptio Symbols Parametric values Fig.4 Applicatio of Wid Load (Bottom View) Total height H 4.m 7.8m 7.m 4 Height of throat top bottom throat level Hthr 7.7m 8. m.6m Dt 6.6m 69.96m 8.m Db m.m.m Dthr 6.m 67.m 68.7m 6 Colum height Hc 9.m.m 9.7m 7 (Hc/H) ratio (Dthr/Db) ratio ad are the existig coolig towers ad is itermediate coolig tower betwee two existig coolig towers. The thickess is varied from mm, mm, 4mm ad mm. The material properties of coolig towers are youg s modulus.mpa, Poisso Ratio. ad Desity of RCC kn/m. The boudary coditios are top ed free ad bottom ed is fixed. The followig Fig. shows odes i model, meshig ad boudary coditios applied to model from frot view, isometric view ad bottom view ad Fig. represets the applicatio of wid loadig to the model from frot view, isometric view ad bottom view. Fig. Applicatio of Wid Load (Frot View) The wid pressures o coolig towers at a give height [ p ] are computed as per the stipulatios of IS: 87 (part )-987. For computig the desig wid pressure at a give height the basic wid speed ( V ) will be take as V b =9 m/s at 9.m height above mea groud level. For computig desig wid speed ( V ) at a height, the risk coefficiet k =.6 will be cosidered. For coefficiet k terrai category as per table IS: 87 (part-)-987 will be cosidered. The wid directio for desig purpose will be the oe which would iduces worst load coditio. Coefficiet k will be for the Tower uder cosideratio. The wid pressure at a give height will be computed theoretically i accordace with the IS codal provisio give as uder b Fig. Nodes, Meshig ad Boudary Coditios (Isometric View).6V p () V V k k k Where b () 4 Iteratioal Joural of Curret Egieerig ad Techology, Vol., No.6 (Dec )

3 Displacemet i Y Directio Displacemet i X Directio Priya Kulkari et al I which p is the horiotal radius at ay vertical coordiate, Y with the origi of coordiates beig defied by the ceter of the tower throat, a is the radius of the throat, ad b is some characteristic dimesio of the hyperboloid. Wid loads o these coolig towers have bee calculated i the form of pressure by usig desig wid pressure co efficiet give i IS 4-98 code.. Tabulatio ad Results. Displacemet Wid effect o Hyperbolic RCC Tower Variatio of Displacemet for Wid Load i X, Y ad Z directio is preseted i Table, Table, ad Table4 ad plotted graphically i Fig.7, Fig.8 ad Fig.9 respectively. The variatio of displacemet i Y ad Z directio is similar. Table Displacemet due to Wid Load i X Directio i Fig.6 Circumferetial Pressure Distributio as per IS code The circumferetial pressure distributio ca be represeted by a Fourier cosie series of the form as give below: 7 ' p f cos (4) f f cos f cos... f7 cos 7 () Where ' p = pressure coefficiet = harmoic costat = horiotal agle measured from the widward meridia f = harmoic costat Values of F for various values of are tabulated below: f The actual desig wid pressure o the shell is obtaied by multiplyig the basic wid pressure as give i IS: by the coefficiet P obtaied above. Fig.7 Variatio of Displacemet for Wid Load i X directio Table Displacemet due to Wid Load i Y Directio i Fig.8 Variatio of Displacemet for Wid Load i Y directio Iteratioal Joural of Curret Egieerig ad Techology, Vol., No.6 (Dec )

4 Max Pricipal Stress at Top (Mpa) Max Pricipal Stress at Bottom (Mpa) Displacemet i Z Directio Mi Pricipal Stress at Top (Mpa) Priya Kulkari et al Table 4 Displacemet due to Wid Load i Z Directio i Fig.9 Variatio of Displacemet for Wid Load i Z directio. Pricipal Stress 4 The maximum ad miimum pricipal stress at top due to wid load is preseted i Table ad Table 6 is plotted graphically i Fig. ad Fig. ad also maximum ad miimum pricipal stress at bottom due to wid load is preseted i Table 7 ad Table 8 plotted graphically i Fig. ad Fig.. It is observed that as the thickess ad height icreases pricipal stress decreases. Wid effect o Hyperbolic RCC Tower Table 6 Mi Pricipal Stress at Top Fig. Variatio of Pricipal Stress due to Wid Load Table 7 Max Pricipal Stress at Bottom Table Max Pricipal Stress at Top Fig. Variatio of Pricipal Stress due to Wid Load Fig. Variatio of Pricipal Stress due to Wid Load Table 8 Mi Pricipal Stress at Bottom Iteratioal Joural of Curret Egieerig ad Techology, Vol., No.6 (Dec )

5 Mi Pricipal Stress at Bottom (Mpa) Priya Kulkari et al Fig. Variatio of Pricipal Stress due to Wid Load Coclusios From the variatio of displacemet i X, Y ad Z directios with thickess ad variatio of max ad mi pricipal stress at top ad bottom, it is evidet that ) Due to wid loadig as the thickess ad height icreases displacemet goes o decreasig. Displacemet i is maximum tha ad. ) The Distortio is miimum at bottom part of shell due to fixed base (i.e. fixity), & maximum at top part of shell. ) Pricipal stress due to wid loadig goes o decreasig with icrease i its thickess ad height. Refereces Techical specificatio for coolig water ooe geeratio plat. X7 MW Bellary STPP.Specificatio No.: PE-TS A. Pushpa B. S, Vasat Vae, P. T. Nimbalkar (4), Performace Evaluatio of Tower i Thermal Power Plat - A Case Study of RTPS Karataka, Iteratioal Joural of Egieerig ad Advaced Techology (IJEAT) ISSN: , Volume-4 Wid effect o Hyperbolic RCC Tower H. Irtaa, S. Ahmad, T. Padey (), D study of wid forces aroud multiple coolig towers usig computatioal fluid dyamics, Iteratioal Joural of Egieerig, Sciece ad Techology Vol., No. 6, pp. 6 Takashi Hara Dyamic Respose of RCC Tower Shell cosiderig supportig systems, Tokuyama College of Techology. Gurfikel G. (97) Aalysis ad Desig of Hyperbolic Towers for uclear plat by cosiderig self weight,earthquake load,wid load ad thermal load. D. Makovicka (6), Respose Aalysis of a RC Tower Uder Seismic ad Widstorm Effects, Acta Polytechica Vol. 46 No. 6. Dr.-Ig. Christia Lag (), Earthquake Behavior of Natural Draft Towers Determiatio of Behavior Factors with Special Regard to Differet Types of Supportig Colum Systems Proceedigs of the 8th Iteratioal Coferece o Structural Dyamics, Eurody Leuve, Belgium, 4-6 G. De Roeck, G. Degrade, G. Lombaert, G. Muller (eds.) ISBN Dieter Busch a, Reihard Harte b, Wilfried B. Kratig c, Ulrich Motag (), New atural draft coolig tower of m of height, Egieerig Structures 4 9. Radhire Mayur A.(4), Performace Improvemet of Natural Draft Tower, Iteratioal Joural of Egieerig Research ad Reviews (IJERR) Vol., Issue, pp: (7-). Prasahath N, Sayeed sulaima (), The effect of Seismic Load ad Wid Load o Hyperbolic Tower of varyig dimesios ad RCC shell thickess, The Iteratioal Joural of Emergig Treds i Egieerig ad Developmet Issue, Vol.4 ISSN Veea N ad Aswath M. U (), Comparative Study of The Effect Of Seismic Ad Wid Loads o Tower With A-Frame Ad H-Frame Colum Supports, The Iteratioal Joural of Sciece & Techoledge ISSN 99X. G. Murali, C. M. Vivek Vardha ad B. V. Prasath Kumar Reddy (), Respose of Towers to Wid Load, ARPN Joural of Egieerig ad Applied Scieces Volume 7, No.. 7 Iteratioal Joural of Curret Egieerig ad Techology, Vol., No.6 (Dec )

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