Laserfiche WebLink
15.4 Strucural Design Requirements DK BARBER RCE 21,110 date 7/30/2012 <br /> Seismic Coefficients for nonbuilding structures not similar to buildings pg 2 of 5 <br /> table 15.4-2 select mechanically anchored flat bottom R=3 <br /> 12.Z2 Effective seismic Weight WE=Total DL+Total LL(operating weight,assume tank's contents at 90%full) <br /> WL= 1,363 + 3,549 = 4,911 LBS <br /> 15.7.6 Ground-Supported Storage Tanks for Liquids <br /> 15.7.6.1 Small tarik anchored treat as rigid,perSection 15.4.2 of#his standard Fundamental Period? eq.12.8-7 <br /> Total V=0.30 SDSW/p V=0.30 x 0.64 x 5,146 x 1.5= 1,414.5 Ta =Cth"n <br /> AST Only Vim=V=0.30 x 0.64 x 1,371 x 1.5= 392.4 from table 12.8-2 All other structural <br /> Contents Only Vcontents=V=0.30 x 0.64 x 3,775 x 1.5= 1,022.1 Ct= 0.02 (from table) systems <br /> x= 0.75 (from table) <br /> 15.4.2 Small tank not anchored treat as rigid per Section,15.4.2 of this standard h= 5.25 (highest point,est.) <br /> _. _. n= 1 (single story) <br /> Ta = 0.069 ,as Ta is<0.06 s <br /> V=0.30 SDSWlp eq.15.4-5 <br /> Overturning Moment apply V at AST cg <br /> where Vim= 392.4 <br /> where Vcpntents= 1022.1 <br /> 1414.5 =Total seismic base shear <br /> heigM of CCy <br /> seismic MV AST=V_ x 2.63 ft = 392.4 Ib x 2.63 ft= 1,033 Ib-ft <br /> seismic My Lt=V ,tx 2.57 ft = 1,022.1 Ib x 2.57 ft= 2,624 Ib-ft combined c.g. <br /> CL of CG,to tipping edge where Mtotal= 3,657 Ib-ft CGy=3729/1482= 2.52 <br /> resist Ma =Wt x CGx = 4,911 Ib x 1.63 ft= 7,981 f.s: 7981/3657= 2.18 f.s. <br /> Sliding without anchorage tipping about edge of AST Tipping No problem <br /> Check if Sliding Compare frictional resistance vs.V although r and sos M;.,rsscl movement is blocked <br /> 15.7.6.1.5 V<WF tan 30- V<5,146 x 0.577 V<2,969 max seismic base shear shall not exceed <br /> 1,414 vs 2,969 f.s: 2969/1414= 2.10 f.s. <br /> Sliding No problem <br /> What happens if horizontal movement during major earthquake? Won't tip over if AST slides westward, <br /> pavement is at same elevation(see photo). Metal wall prevents northward travel. <br /> Flotation: Empty Weight= 1,363 lbs Footprint(SF)= 17.06 Bouyant at 1.28 FT Inundation if AST Empty. <br /> Flotation due to flooding is not a concern at this location,tank could float if water was 1.28 FT deep <br /> and AST empty. Review of FEMA Map does not suggest flooding in less than 100 year event. <br /> P <br />