Project Job Ref. Section Sheet no./rev. 1

1 Advanced Engineering SolutionsLtdProjectJob EngineeringSheet byKevin MillerDate16/05/2008 Chk'd byKevin MillerDateApp'd byDateRAFT FOUNDATION DESIGN (BS8110 : Part 1 : 1997)TEDDS calculation version ;Library item-Raft titlehedgebedgeaedgehslabhhcoreslabhhcor ethickAsslabtopAsedgetopAsslabbtmAsedgeb tmAsedgelinkSoil and raft definitionSoil definitionAllowable bearing pressure;qallow= of types of soil forming sub-soil;Two or more typesSoil density;FirmDepth of hardcore beneath slab;hhcoreslab=150mm;(Dispersal allowed for bearing pressure check)Depth of hardcore beneath thickenings;hhcorethick=250mm;(Dispersal allowed for bearing pressure check)Density of hardcore; hcore= assumed diameter of local depression; depbasic=2500mmDiameter under slab modified for hardcore; depslab= depbasic-hhcoreslab=2350mmDiameter under thickenings modified for hardcore; depthick= depbasic-hhcorethick=2250mmRaft slab definitionMax dimension/max dimension between joints;lmax= thickness;hslab=250mmConcrete strength;fcu=40N/mm2 Poissons ratio of concrete.

2 = mesh reinforcement strength;fyslab=500N/mm2 Partial safety factor for steel reinforcement; s= C&CA document Concrete ground floors Table 5 Minimum mesh required in top for shrinkage;A142;Actual mesh provided in top;A393 (Asslabtop= 393 mm2/m)Mesh provided in bottom;A393 (Asslabbtm= 393 mm2/m)Top mesh bar diameter; slabtop=10mmBottom mesh bar diameter; slabbtm=10mmCover to top reinforcement;ctop=50mmCover to bottom reinforcement;cbtm=75mmAverage effective depth of top reinforcement;dtslabav= hslab-ctop- slabtop=190mmAverage effective depth of bottom reinforcement;dbslabav= hslab-cbtm- slabbtm=165mmOverall average effective depth;dslabav= (dtslabav+ dbslabav)/2 =178mmMinimum effective depth of topreinforcement;dtslabmin= dtslabav- slabtop/2 =185mmMinimum effective depth of bottom reinforcement;dbslabmin= dbslabav- slabbtm/2 =160mmEdge beam definitionOverall depth;hedge=500mmAdvanced Engineering SolutionsLtdProjectJob EngineeringSheet byKevin MillerDate16/05/2008 Chk'd byKevin MillerDateApp'd byDateWidth.

3 Bedge=500mmAngle of chamfer to horizontal; edge=60degStrength of main bar reinforcement;fy=500N/mm2 Strength of linkreinforcement;fys=500N/mm2 Reinforcement provided in top;2 T20 bars (Asedgetop= 628 mm2)Reinforcement provided in bottom;2 T20 bars (Asedgebtm= 628 mm2)Link reinforcement provided;2 T10 legs at 250 ctrs (Asv/sv= mm)Bottom cover to links;cbeam=35mmEffective depth of top reinforcement;dedgetop= hedge-ctop- slabtop- edgelink- edgetop/2 =420mmEffective depth of bottom reinforcement;dedgebtm= hedge-cbeam- edgelink- edgebtm/2 =445mmInternal slab design checksBasic loadingSlab self weight;wslab= 24 kN/m3 hslab= ;whcoreslab= hcore hhcoreslab= loadingUniformly distributed dead load;wDudl= distributed live load;wLudl= load number 1 Load type;Point loadDead load;wD1= load;wL1= load;wult1= wD1+ wL1= dimension 1;b11=440mmLoad dimension 2;b21=440mmInternal slab bearing pressure checkTotal uniform load at formation level.

4 Wudl= wslab+ whcoreslab+ wDudl+ wLudl= pressure beneath load number 1 Net bearing pressure available to resist point load;qnet= qallow-wudl= ultimate bearing pressure available;qnetult= qnet wult1/(wD1+ wL1) = area required at formation;Areq1= wult1/qnetult= of cantilever projection at formation;p1= max(0 m, [-(b11+b21) + ((b11+b21)2-4 (b11 b21-Areq1))]/4)p1= of cantilever projection at u/side slab;peff1= max(0 m, p1-hhcoreslab tan(30)) = loaded area at u/side slab;Aeff1= (b11+ 2 peff1) (b21+ 2 peff1)= net ult bearing pressure at u/side slab;qnetulteff= qnetult Areq1/Aeff1= bending moment;Mcant1= qnetulteff peff12/2 = required in bottomMaximum cantilever moment;Mcantmax= factor;Kslabbp= Mcantmax/(fcu dbslabmin2) = arm;zslabbp= dbslabmin min( , + ( )) = of steel required.

5 Asslabbpreq= Mcantmax/(( s) fyslab zslabbp) =89mm2/mPASS-Asslabbpreq<= Asslabbtm-Area of reinforcement provided to distribute the load is adequateThe allowable bearing pressure will not be exceededAdvanced Engineering SolutionsLtdProjectJob EngineeringSheet byKevin MillerDate16/05/2008 Chk'd byKevin MillerDateApp'd byDateInternal slab bending and shear checkApplied bending momentsSpan of slab;lslab= depslab+ dtslabav=2540mmUltimate self weight udl;wswult= wslab= weight moment at centre;Mcsw= wswult lslab2 (1 + ) / 64 = weight moment at edge;Mesw= wswult lslab2/ 32 = weight shear force at edge;Vsw= wswult lslab/ 4 = due to applied uniformly distributed loadsUltimate applied udl;wudlult= wDudl+ wLudl= at centre;Mcudl= wudlult lslab2 (1 + ) / 64 = at edge;Meudl= wudlult lslab2/ 32 = force at edge;Vudl= wudlult lslab/ 4 = due to load number 1 Moment at centre;Mc1= wult1/(4 ) (1+ ) ln(lslab/min(b11, b21)) = at edge;Me1= wult1/(4 ) = dispersal width for shear;bv1= min(b11+ 2 b21, b21+ 2 b11) = shear force.

6 V1= wult1/ bv1= moments and shearsTotal moment at edge;M e= moment at centre;M c= shear force;V = required in topK factor;Kslabtop= M e/(fcu dtslabav2) = arm;zslabtop= dtslabav min( , + ( )) = of steel required for bending;Asslabtopbend= M e/(( s) fyslab zslabtop) =143mm2/mMinimum area of steel required;Asslabmin= hslab=325mm2/mArea of steel required;Asslabtopreq= max(Asslabtopbend, Asslabmin) =325mm2/mPASS-Asslabtopreq<= Asslabtop-Area of reinforcement provided in top to span local depressions is adequateReinforcement required in bottomK factor;Kslabbtm= M c/(fcu dbslabav2) = arm;zslabbtm= dbslabav min( , + ( )) = of steel required for bending;Asslabbtmbend= M c/(( s) fyslab zslabbtm) =310mm2/mArea of steel required.

7 Asslabbtmreq= max(Asslabbtmbend, Asslabmin) =325mm2/mPASS-Asslabbtmreq<= Asslabbtm-Area of reinforcement provided in bottom to span local depressions is adequateShear checkApplied shear stress;v = V /dtslabmin= steel ratio; = 100 Asslabtop/dtslabmin= BS8110-1:1997-Table ;Design concrete shear strength;vc= <= vc-Shear capacity of the slab is adequateInternal slab deflection checkBasic allowable span to depth ratio;Ratiobasic= factor;Mfactor= M c/dbslabav2= service stress;fs= 2/3 fyslab Asslabbtmbend/Asslabbtm= Engineering SolutionsLtdProjectJob EngineeringSheet byKevin MillerDate16/05/2008 Chk'd byKevin MillerDateApp'd byDateModification factor;MFslab= min( , + [(477N/mm2-fs)/(120 ( + Mfactor))])MFslab= allowable span to depth ratio;Ratioallow= Ratiobasic MFslab= span to depth ratio;Ratioactual= lslab/ dbslabav= <= Ratioallow-Slab span to depth ratio is adequateEdge beam design checksBasic loadingHardcore;whcorethick= hcore hhcorethick= beamRectangular beamelement;wbeam= 24 kN/m3 hedge bedge= element.

8 Wchamfer= 24 kN/m3 (hedge-hslab)2/(2 tan( edge)) = element;wslabelmt= 24 kN/m3 hslab (hedge-hslab)/tan( edge) = beam self weight;wedge= wbeam+ wchamfer+ wslabelmt= load number 1 Load type;Longitudinal line loadDead load;wDedge1= load;wLedge1= load;wultedge1= wDedge1+ wLedge1= line load width;bedge1=140mmCentroid of load from outside face of raft;xedge1=0mmEdge beam bearing pressure checkEffective bearing width of edge beam;bbearing= bedge+ (hedge-hslab)/tan( edge) =644mmTotal uniform load at formation level;wudledge= wDudl+wLudl+wedge/bbearing+whcorethick= of longitudinal and equivalent line loads from outside face of raftLoad x distance for edge load 1;Moment1= wultedge1 xedge1= of ultimate longitud l and equivalent line loads; UDL = of load x distances; Moment = of loads;xbar= Moment/ UDL =0mmInitially assume no moment transferred into slab due to load/reaction eccentricitySum of unfactored longitud l and eff tive line loads; UDLsls = bearing width;ballow= 2 xbar+ 2 hhcoreslab tan(30) =173mmBearing pressure due to line/point loads.

9 Qlinepoint= UDLsls/ ballow= applied bearing pressure;qedge= qlinepoint+ wudledge= <= qallow-Allowable bearing pressure is not exceededEdge beam bending checkDivider formoments due to udl s; udl= bending momentsSpan of edge beam;ledge= depthick+ dedgetop=2670mmUltimate self weight udl;wedgeult= wedge= slab udl (approx);wedgeslab= max(0 kN/m, wslab (( depthick/2 3/4)-(bedge+(hedge-hslab)/tan( edge))))wedgeslab= weight and slab bending moment;Medgesw= (wedgeult+ wedgeslab) ledge2/ udl= shear force;Vedgesw= (wedgeult+ wedgeslab) ledge/2 = Engineering Soluti