Sheet113-Jul-10Response to EIL comments on document EPL/6907/167/RAD/001 rev. 2 as received through email dated 07.07.2010EIL CommentsOur RepliesLOAD CALCULATIONS1) Refer Point 2.0 9, Header Box Length considered as 4012mm instead of 4332 actual, to be modified.Will be corrected accordingly2) Refer Point 2.0 9, Header Box refractory weight calculation is wrong.to be corrected as per area modified3) Refer Point 2.0 9 Unit of weight is considered is wrong i.e. should be Kg instead of Kg/sqm.density=1200 kg/cubm, 1200*(50/1000)=60 kg/sqm, 60*area = kg; (eg 60*0.6*4.332=156 kg)4) Refer Point 3.0, Burner load is concentrated at center not to be applied on the whole floor.Ok, will be distributed in area enveloping the burner locations5) Refer Point 4.0, Why floor sleeve weight is considered in Coil weight.4.7 kg will be deducted6) Refer Point 4.0, Radiant coil is always hanging in this heater and is never resting on the floor. Hence 100% load to be applied on the channel supporting the Radiant coil.OK, 100% will be applied on supporting beam7) Refer Point 4.0, Crossover, coil inlet to convection and Coil outlet from radiant weights to be considered in design and applied on the suitable locations.OK8) Refer 10.0, Wind reduction Factor on the convection column to be rechecked based on the member welded to plate on one side.as per cl 6.3.3.2-a-I : l/b is doubled as 2*43=86, hence from table 25, K=0.959) Refer 10.0, Stack ODs considered in stress check, weight calculation sheets are not matching with the drawings. To be corrected.corrected in Appendix-110) Wind Load calculations for circular shells are done on projected areas not on the actual circle. Load calculations modified accordingly.Wind load on stack shell - static wind - will be applied at nodes as per appendix-1, for radiant shell shape factor of 0.7 will be used11) Platform Drag winds are to be considered as ~10% of the total wind load. To be modified accordingly.OKSTACK:1) Shell length considered in the model for different plate thickness is not matching with the drawings to be modified accordingly.Corrected.2) 25% live load to be considered for natural frequency calculations.Done3) Refer Deflection Case, Load 4:a) Floor load applied in stack design is of no advantage.Removedb) Off-take duct is in no way connected to Stack floor. It is free to expand.it's load removed4) Refer Deflection Case, Load case 6 Off-take Duct load need not be applied. It is free to expand.it's load removed5) Refer Deflection Case, where load case -2 is used?load case 2 is for refractory. Removed, since load case 3 (= refractory + corrosion) is used6) Refer Deflection Case, for checking deflection all loads are to be multiplied by 1.1done7) Refer Deflection Case, Instead of load case 2, load case 3 to be used in minimum loads.yes, it is already used.8) Refer Stability Case:a) Where load case -2 is used?same as point 5 above, removedb) Off-take duct is in no way connected to Stack floor. It is free to expand.OK, its load removedc) Floor load applied in stack design is of no advantage.removedd) Load combination used in Load case 15 is wrong should be 1.6 x load1 + 1.6 x load 4 + 1.6 x load 3 + 1.6 x load 6. There will be no deduction as none of the load is reducing the stress.donee) Instead of load case 2, load case 3 to be used in minimum loads.done9) Refer Maximum stress case:a) Refer maximum load case 10 % design margin to be taken on all loads.doneb) Instead of load case 2, load case 3 to be used in minimum loads.doneSTAIRCASE:A) Structure1) All the bracings are considered as rigid type connections. In actual case these joints released joints carrying tension and compression load only. These are to be modified accordingly.OK, will be checked for released ends2) For platforms at the individual levels, connections which are main load carrying and which are secondary members are not properly identified. Like L 75x75x8 considered as secondary members are not released. In actual fabrication/construction these will be released type i.e. (My and Mz released). These are to be modified accordingly.OK3) For the Platform at EL+17200, the supports considered are not present in the actual case. In actual case this platform and the platform on the heater structure are separated by providing a gap on 50mm so that no load from Heater is transferred to Staircase and vice versa. So supports considered are to be removed and a continuous member to run from Grid 11 and 10 where supports are considered.OK4) For Interconnecting platforms at other levels, the supports considered shall be shear type only, i.e. transferring dead load only.yes, only vertical load is transferred5) In our opinion the bracings considered in N S direction on the main structure, are not required, as this is the stronger side of the Columns.OK, structure will be checked without these bracings6) The platform width considered at EL+13500 is 900mm as against 1200mm required as per drawing. This is to be modified accordingly.OKA) Loading:1) Handrail load is not considered on the PTFM EL+3000, 6000, 8400, 11050, 13500 in E W direction.OK2) Dead load of the stair treads not considered in the design.OK3) Live loads all platforms (except platform at EL+17200) and stair treads to be considered as 250Kg/m2 instead of 300Kg/m2.OK4) Cf factor (as per table 28) against solidity ratio is not considered in design.OK, then wind load is applied on members only and not on area basis5) Solidity ratio cannot be same in both the planes i.e. N S and E W.OK, will b echecked separately for both directions6) Wind load on the Stair stringer to be considered in design.OK, same as 4 above7) Wind load drag (~10%) of the total load (based on area to account for hand rails and drag force on gratings) to be considered in design).OK, will be applied at column nodes8) Wind load in N S is applied in wrong direction i.e. instead of x-axis applied on z-axis.will be corrected9) Wind load coming on the main beams is not applied. Without this actual beam design is not carried out.OK, same as 4 & 6 above10) In maximum dead load combination why a factor 1.1 is to be considered for all loads.we understand factor 1.1 is to be used for all loads11) In minimum dead loads platform live loads are to be neglected as per Job spec.OK12) In load case Max DL + Wind, factor of 1.1 is to be considered for all loads.OK13) In Seismic Load Case i.e. Load 5 and Load 6, live loads are to taken as 25% of the total live loads as per table-8 of IS-1893 (Part-1) 2002.OK14) Damping factor considered in design as 0.002 i.e. 0.2% instead of 2%.OKHEATER:A) Structure1) EL+3000a) For platform main beams for design consider MB200, in fabrication provide MB200+Cut Beam.OK, presently modelled are taper section of MB200+cut beam MB200b) Floor plate modeled at the centre is not correct. 3 node plate to be considered in design.OK,c) For platforms the secondary members considered i.e. angle 75x75x8 are not rigidly connected to platform, should be released type.OKd) Connection of the outer ring i.e. MC200 and secondary member MC150 to be relooked upon based on the actual details to be used.it is welded connection2) End connection of MC150 radiant shell stiffener rings to be relooked upon based on the details actually used as per standard practice these are of released type.we have considered welded connection, will be modified to released3) Piping support not modeled at EL+15450.Load is considered on member 5829 - load case 12, however we will try to model the support separately.4) For bottom main column size plate width to be taken as 230mm instead of 400mm. Base plate stiffeners should not be taken into design.OK, actually width of plate itself is taken as 400 mm, we will modify.5) Platform at EL+6000, 8400a) For platforms the secondary members considered i.e. angle 75x75x8 are not rigidly connected to platform, should be released type.OKb) Connection of the outer ring i.e. MC200, secondary members MC150 to be relooked upon based on the actual details to be used.OKc) Inner ring to be taken as MC200 instead of MC150.OK, we will change it to MC2006) Platform at EL+11050, 13500a) Channel connecting the main columns to be taken as MC200 instead of MC150.OK, we will change it.b) The main load transfer beams to be taken as MB200 in N S dir and MB300 in E W dir. During fabrication these may be provided with cut beam.We understand this is in reference to beams on columns beyond grid s 10 & 11, in N-s dir it is already MB200 , in E-W dir beyond grids 10 & 11 to be modified as MB300.c) Connection of the secondary members i.e. angle 75x75x8 and MC150 to be relooked upon based on the actual details to be used.OKd) For Main platform cantilever beams at El+17200, MB200 may be modeled instead of taper beam and during fabrication cut beam may be provided.OK7) For stack platforms MB200 to be used for main beams instead of MB150.OK, done8) For Stack supporting beams option of use of standard beam i.e. MB400 or MB300 with plates may be looked into instead of plate fabricated beams.We are making the arrangement for your approval9) Plate thickness modeled to taken as corroded thickness instead of un-corroded thickness for radiant floor, shell, arch, convection long wall, breeching and convection end wall.OK, will be modified;however, we are checking the streses in these plate elements, the selfweight will be reduced,10) The Convection long wall stiffeners modeled are incorrect i.e. Plate 75x6 instead of angle 75x75x6 required.OK, flats will be revised to angle 75x811) Angle Brace provided below the stack supporting beam will not serve the purpose. As angle is less than 45 deg. This should be replaced with Girder.same as 9 aboveWe are modelling this type of truss, to be approved.B) Loading (wind Load)1) As explained above there is no interconnection between the staircase and Heater structure at EL+17200, hence the load considered in the self-weight to be deleted.OK2) Following loads are to be considered for interconnecting platforms between staircase and heater as 100 Kg at each node for dead load and 170 Kg on each node for live loads instead of the loads from staircase model.OK, loads used from stair reactions will be deleted and these loads will be used.3) Refractory load taken on the long wall be broken into three parts as per the load calculation sheet.OK4) Radiant coil is always hanging in this heater and is never resting on the floor. Hence 100% load to be applied on the channel supporting the Radiant coil.OK, same as 6 in 'load calculations'5) Burners load is concentrated in the inner ring of the floor plate. Load to be modified accordingly.OK, same as 4 in 'load calculations'6) Header box load calculation is not correct, load applied to be modified after the load workout.OK, same as 1 & 2 in 'load calculations'7) Off-take duct load to be applied in maximum dead load and refractory dead load.OK8) Refer Load 11:a) There is no soot blower in this Heater, why soot blower load is applied.It is a typing error, it should have been steam lancing, since there is no extra load due to this, this will be removed.b) Load from staircase is already applied in Load 1 and Load 6 why it is repeated here.stair case is not modelled with heater, hence reactions from stair case at these elevations are applied here. However as per point no. 2 above, these will be removed.c) Piping support to be modeled and load to be applied on the same at EL+5450 and EL+15700.They are included in load case 11-misc loads, but not applied exactly at 5.45 and 15.7, they are at el 6.0 and 15.3, will be modified.d) Load on Tube pulling Bracket to be increased to 350 Kg considering one U being pulled.OK9) Refer Load 12 to 15:a) Load calculations for circular shells are done on projected areas not on the actual circle.yes, same as 10 in 'load calculations'Load applied radiant and stack to be modified accordingly.yes, same as 10 in 'load calculations'b) Platform drag loads to be applied (~10% of total calculated wind load).OK - same as 11 in 'load calculations'c) Wind Load on the Radiant columns to be applied.OKd) Shape factor of 1.2 is not considered in the design when applying wind loads on rectangular surfaces.OK, will be includede) Wind load on off-take and drag wind load on Breeching to be applied.OKf) Wind load from interconnecting staircase platforms to be negated as these joints are shear.OKg) Wind load from Header boxes (direct and Drag load) not applied to be applied.OK, will be addedh) There no wind load on ETS as it is shielded from Header box.OKi) Dynamic Wind calculated will change based on comments given above.done10) In maximum dead load combination why a factor 1.1 is to be considered for all loads.??, 1.1 will be considered for all loads11) Header Box Load and Burner Loads to be deleted in the minimum dead load case. Instead of load case 2, load case 3 to be used in minimum loads.OK12) Load case 23 to 30 to be modified as per the comments given in point 10 and 11.OKC) Loading (Siesmic Load)1) Refer comments given in point 1 to 7, 9, and 11 of Loading (Wind).OK2) Damping factor considered in design as 0.002 i.e. 0.2% instead of 2%.it is 0.02,

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