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Challenge

Week 6 Challenge

MMd Nizamuddin Mondal14 Aug 2023
BridgesStructural Analysis
 
  • Introduction
      
        Design Philosophy@ RCC Box Type Strucure        
1 Description of structure            
  Geometry Model            
  The RCC box structure is modelled as a plane frame in Staad Pro software and the corresponding analysis is done
2 Design Standards            
  Codes & Standard            
  The design of various components of the bridge, in general are based on provisions of IRC.   
  The list of IRC Codes( latest revisions) given below will serve as a guide for design of structure
  IRC 005-2015 Standard Specifications and Code of Practice for Road Bridges, Section I — General Features of Design
  IRC 006-2014 Standard Specifications and Code of Practice for Road Bridges, Section-II Loads and Load Combinations
  IRC 112-2011 Code of Practice for Concrete Road Bridges        
3 Loading              
3.1 Deal Load(DL)            
  Unit weight for Dead Loads calcualtion has been considered by adopting unit weight as per IRC"6-2014
  Standard Specifications and Code of Practice for Road Bridges, Section-II Loads and Load Combinations
3.2 Super-Imposed Deal Load(SIDL)          
  Unit weight for Super-Imposed Deal Load shall be confirmity with  IRC"6-2014    
  Standard Specifications and Code of Practice for Road Bridges, Section-II Loads and Load Combinations
3.3 Load due to Earth Pressure          
  Static Earth Pressure has been considered to be acting on the vertical wall of the RCC Box.   
  Earth pressure co-efficient has been taken as 0.5        
3.4 Carriage way Live load(CWLL)          
  Live loads confirming to IRC 6-2011 have been considered in the anlysis of the RCC Box Structure and 
  Class of loading w1hichover produces the severe effect has been considered in the design.  
  Transverse dispersion through W/C has been considered.      
  Longitudinal dispersion through W/C and effective slab thckness has been considered as per IRC 112-2011
3.5 Live Load live load Surcharge          
  The RCC box structure has been analysed considering a live load surcharge     
  equivalent to 1.2 metre height of Earthfill.         
3.6 Load due to Temperature Variation          
  Uniform temperature as well as temperature gradient has been considered as per clause 215 of IRC 6.  
3.6 Load combination             
  Load combination for limited  given iAnnexture B of  IRC 6 has been considered.    
  The following limit states are considered.          
3.6.1 Ultimate limit state(ULS)          
  Under this limit state,             
3.6.1.1 Bending moment checked        
3.6.1.2 Shear force checked        
3.6.2 Serviceability limit state (SLS)          
  Under this limit state:-            
3.6.2.1 Stress In concrete          
3.6.2.2 Stress in Reinforcement        
3.6.2.3 Crack width           
3.6.2.4 Deflection          
4 Structural Analysis:            
  The analysis of the RCC box bridge has Modelled as a 2D structure in a Start Pro.The live load dispersion has been considered according to informative annexure B of IRC 112-2011 i.e. effective width methods. Since the box is fully resting on the soil, the basis support. Condition was simulated by providing discrete spring supports for the base slab. Soil springs stiffness has been calculated based on safe bearing capacity of soil. 
5 Durability and Maintenance considerations:        
5.1 Concrete.              
  Grade of concrete for RCC box.       = M30  
  Grade of concrete for PCC works.       = M15  
5.2 Reinforcement.              
  HYSD bars. Grade Fe500D conforming to IS 1786 2008 and eight are provided as reinforcement.  
5.3 Clear cover.              
  The minimum cover. 2 reinforcement has been determined from the recommendations of IRC:112-2011, taking into account the local environmental conditions.  Following clear cover has been adopted for the various components:-  
  A structural component having faces in contract with Earth = 75 mm
  A structural component having faces not in contact with earth = 50 mm
  Foundation.           75 mm
5.4 Condition of exposure.            
  Condition of exposure is taken as moderate         
                 
5.5 Soil properties.             
  For the soil used for the backfilling  the density has been taken as 2.0 tonne/ m3  as far IRC:6-2011
  The SBC for the box structures has been taken as per sub - soil  investigation report.   
6 Load cases.              
6.1 Dry condition(No fill)            
  Load case.   Title.            
  1   Self weight          
  2   Super impose load due to wearing code.  +UDL due to profile correction course.  
  3   Earth pressure at rest.          
  4   Live load on top 70 a truck.(2 lane and 4 lane. )     
  5   Live load on  top (40 tonne Bogie) (2 lane and 4 Lane.)  
  6   Live load surcharge both sides.        
  7   Live load surcharge left side.        
  8   Live load surcharge right side.        
  9   Braking force left side.          
  10   Braking force right side.          
  11   Uniform temperature rise.        
  12   Uniform temperature fall.        
  13   Temperature gradient rise.        
  14   Temperature gradient fall.        
  15   Live load on top( class AA tracked). 02 Lane and 4 Lane)    
  16   Paver load as suggested by client.        
    Ultimate limit state          
    For checking capacity of section for flexure and shear, basic combination is used.  
    Serviceability limit state          
    For checking stresss in concrete and reinforcement.  Rare combination is used.  
    For Checking cracked width,Quasi-, permanent is used.     
    Deflection is checked for live load only as per clause 12.4 of IRC: 112 -2011  
  • GAD of the Structure:-

                                                                                              Cross-Section View

Design of single cell box structure of 12.00 metre x 5.50 metre with Cushion(H=1.0 m)  
1 Design data.                              
  No of Cells                       =           1.00 No
  Clear span.  ( Skew)                     =         12.00 m
  Clear spn.  ( Sq)                       =         12.00 m
  Clear height at outer edge                   =           5.50 m
   Clear height at median edge                   =           5.50 m
  Skew angle                       =                -   o
  width of Box                       =         12.50 m
  carriage Width                       =         11.50 m
  Width of Crash barrier                     =           0.50 m
  Width of footpath/Safety kerb                   =           0.50 m
  Width of Hunch                       =           0.15 m
  Depth of Hunch                       =           0.15 m
  Thickness of Wearing Coat                   =                -   m
  Thickness of profile correction course(PCC)               =                -   m
  Thickness of wearing coat + profile correction course             =                -   m
  thickness of fill over top slab excluding wearing coat             =           1.00 m
  Depth of Top slab                     =           0.85 m
  Depth of Bottom Slab                     =           0.90 m
  Depth of External Vertical wall                   =           0.90 m
  Safe Bearinfg Capcity                     =       120.00 kN/m2
  Allowable Settlement                     =         75.00 mm
  Spring Constant                       =    1,600.00 kN/m3
  Density of Concrete                     =         25.00 kN/m3
  Bulk Density of Soil                     =         20.00 kN/m3
  Density of Submerged Soil                   =         10.00 kN/m3
  Density of Profile corrective course                 =         25.00 kN/m3
  Density of Fill                       =         20.00 kN/m3
  Co-efficient of earth pressure at rest                 =           0.50  
  Maximum air shade temperature                   =         45.00 oC
  Minimum air temperature                   =         10.00 oC
  Maxumum liv eload on box for braking force calcualtion             =       700.00 kN
1.1 Design Parameters                          
  Grade of concrete.                        =  M30  m
  Grade of steel.                         =  Fe500  m
   Clear cover for earth face structural component.                 =         75.00 mm
  Clear cover for inside face structural component.                 =         50.00 mm
  Clear cover for foundation.                     =         75.00 mm
1.2 Data for Staad input                     =   m
  No of division of Bottom Slab                   =         10.00  
2 Load Calcualtions                     =   m
2.1 Dead Load                       =   m
  Self weight of the structure has been calculated directly.  Start profile in Staad file by the comment ''Self-Weight"     =   m
2.2 Superimposed dead load.                     =   m
  Thickness of Wearing+ profile correction course               =                -   m
  Load(UDL) on top slab   =  (0*25)                =                -   kN/m
  Height of Fill     =  (1*20)                =         20.00 kN/m
                            =         20.00 kN/m
  Total SIDL on the top slab                   =   m
2.3 Earth Pressure   =   m
                            =   m
  Thickness of Top Slab                     =           0.85 m
  height of top Hunch                     =           0.15 m
  Clear Height between top and bottom slab               =           5.50 m
  Height of Bottom Hunch                     =           0.15 m
  Thickness of Botto Slab                     =           0.90 m
    height from top of cushion Top
(m)		 Intensity of Earth pressure(kN/m2)                      
            1.43    1.43 (0.5*1.425*20)                   =         14.25 m
            0.43    1.85 (0.5*1.85*20)                   =         18.50 m
            0.15    2.00 (0.5*2*20)                   =         20.00 m
            5.20    7.20 (0.5*7.2*20)                   =         72.00 m
            0.15    7.35 (0.5*7.35*20)                   =         73.50 m
            0.45    7.80 (0.5*7.8*20)                   =         78.00 m
2.4 Live Load surcharge                          
  Equivalent heigth                     =           1.20 m
  Uniform Intensity of Loading    =(1.2*20*0.5)      Cl.214.1.1.3,Fig3,IRC6-2014   =         12.00 kN/m2
2.5 Braking Force                       =   m
  Max. Live Load on Box for 2 lane                   =       700.00 kN
  Width of the box                       =         12.50 m
  Braking load        =(20%+5% of *700)/12.5    Cl.211.2(a),IRC6-2014   =         14.00 m
2.6 Temperature                       =   m
  Maximum Effective bridge temperature   As per Cl.215.2 ,IRC:6-2014   (45-10)>20,(45+10)/2+10 =         37.50 oC
  Minimum Effective bridge temperature   As per Cl.215.2 ,IRC:6-2015   (45-10)<20>   =         17.50 oC
  Maximum uniform raise of  temperature   45-17.5             =         27.50 oC
  Minimum uniform raise of  temperature   10-37.5             =        -27.50 oC
2.7 UDL due to eccentricity of Live Load                      
  length of Box            =(12+0.9*0.5)          =         13.80 m
  Width of the Box                      =         12.50 m
  Section Modulus of Box transverse      =(13.8*12.5^2)/6          =       359.38 m3
  Section Modulus of Box longitudinal      =(12.5*13.8^2)/6          =       396.75 m3
  1 No 70R Tracked                     =   m
  Carriage live load                     =       700.00 kN
  Transverse eccentricity of live eload  =(12.5/2)-0.5-1.2-2.9/2)            =           3.10 m
  Transverse Moment       =(700*3.1)              =    2,170.00 kN-m
  Udl due to Eccentricity of CWLL    =(2170/359.375)              =           6.04 kN/m
  Longitudinal eccentricity of live eload  =((12+0.9)-6.27)/2              =           3.31 m
  Longitudinal  Moment       =(700*3.305)              =    2,313.50 kN-m
  Udl due to Eccentricity of CWLL    =(2313.5/396.75)              =           5.83 kN/m
3 Live Load Calculation                     =   m
  Design data.                              
  No of Cells                       =           1.00 No
  Clear span.  ( Skew)                     =         12.00 m
  Clear spn.  ( Sq)                       =         12.00 m
  Clear height at outer edge                   =           5.50 m
   Clear height at median edge                   =           5.50 m
  Skew angle                       =                -   o
  width of Box                       =         12.50 m
  carriage Width                       =         11.50 m
  Width of Crash barrier                     =           0.50 m
  Width of footpath/Safety kerb                   =           0.50 m
  Width of Hunch                       =           0.15 m
  Depth of Hunch                       =           0.15 m
  Thickness of Wearing Coat                   =                -   m
  Thickness of profile correction course(PCC)               =                -   m
  Thickness of wearing coat + profile correction course             =                -   m
  thickness of fill over top slab excluding wearing coat             =           1.00 m
  Depth of Top slab                     =           0.85 m
  Depth of Bottom Slab                     =           0.90 m
  Depth of External Vertical wall                   =           0.90 m
  As per IRC:6-2014                          
  For 20 tonne Boggie Load L-type                      
  Clear Distance from the kerb                   =           1.20 m
  Width of track Transverse to traffic direction)               =           0.86 m
  Width of track along traffic direction)   Cl.204.1,IRC:6-2014         =         0.263 m
  Total Width of Vehicle                     =           2.79 m
  Width centre to centre of wheel     (2.79-0.86/2-0.86/2)         =           1.93 m
                                 
  For 70R-Tracked                            
                            =    
  Clear Distance from the kerb                   =           1.20 m
  Width of track Transverse to traffic direction) Cl.204.1, Fig-1,IRC:6-2014         =           0.84 m
  Width of track along traffic direction)   Cl.204.1, Fig-1,IRC:6-2014         =         4.570 m
  Total Width of Vehicle       Cl.204.1, Fig-1,IRC:6-2014         =           2.90 m
  Width centre to centre of wheel     (2.9-0.84)             =           2.06 m
                                 
  For Class AA-Tracked                          
                                 
  Clear Distance from the kerb                   =           1.20 m
  Width of track Transverse to traffic direction) Cl.204.1, Fig-1,IRC:6-2014         =           0.85 m
  Width of track along traffic direction)   Cl.204.1, Fig-1,IRC:6-2014         =         3.600 m
  Total Width of Vehicle       Cl.204.1, Fig-1,IRC:6-2014         =           2.90 m
  Width centre to centre of wheel     (2.9-0.85)             =           2.05 m
  For 40 tonne Boggie Load L-type                      
  Impact factor                       = 25%  
  Effective Dispersion width:-                   =    
  For Along the traffic direction                   =    
  Dispersion of loads through fills and wearing coat(at Angle 45o)           =    
      beff = bt+2(wc+d+s)               =    
  Where                         =    
      bt = Tyre width along traffic flow           =         0.263 m
      wc =  Wearing coat thickness             =                -   m
      d  = Effective deck Slab             =           0.85 m
      s = Depth of soil above box             =           1.00 m
              Dispersion width alon traffic           beff =         3.963 m
                                 
  For perpendicular of the traffic direction                    
                                 
      beff = k*x(1-x/lo)+b1                    
  Where                              
      k = Constant depending on b/lo     Table 4.6,IRC:112-2011(Annexure-B3)   =         2.627  
      lo = effective span               =         12.90  
      x = Distance of centre of gravity  of load from nearest support (10.7-1.22)/2 =           5.84 m
      x = Width of track along traffic direction)    `/2    0.263/2   =         0.132 m
      wc =  Wearing coat thickness             =                -   m
      bt = tyre width across traffic flow           =           0.86 m
      b1 = width of tyre(bt)+2*(thickness of wearing coat or finish surface above the slab) 0.86+2*1.1   =           3.06 m
      b  = Width of box               =         12.50 m
                        Dispersion width alon traffic, for max moment case beff =       11.457 m
                        Dispersion width alon traffic, for max vertical load  case beff =         3.402 m
For  70R -Tracked                          
Impact Factor                       = 10%  
Effective Dispersion width:-                   =    
For Along the traffic direction                   =    
Dispersion of loads through fills and wearing coat(at Angle 45o)           =    
    beff = bt+2(wc+d+s)               =    
Where                         =    
    bt = Tyre width along traffic flow           =         4.570 m
    wc =  Wearing coat thickness             =                -   m
    d  = Effective Depth of Deck Slab           =           0.85 m
    s = Depth of soil above box             =           1.00 m
            Dispersion width alon traffic           beff =         8.270 m
For perpendicular of the traffic direction                    
                               
    beff = k*x(1-x/lo)+b1                    
Where                              
    k = Constant depending on b/lo     Table 4.6,IRC:112-2011(Annexure-B3)   =         2.627  
    lo = effective span               =         12.90  
    x = Distance of centre of gravity  of load from nearest support (10.7)/2   =           6.45 m
    x = Tracked width        `/2    0.263/2   =         2.285 m
    wc =  Wearing coat thickness             =                -   m
    bt = tyre width across traffic flow           =           0.84 m
    b1 = width of tyre(bt)+2*(thickness of wearing coat or finish surface above the slab) 0.86+2*1.1   =           2.84 m
    b  = Width of box               =         12.50 m
                      Dispersion width alon traffic, for max moment case beff =       11.313 m
                      Dispersion width alon traffic, for max vertical load  case beff =         7.780 m
Maximum Moment Case
Longitudinal Dispersion =           8.27 m
Tranverse dispersion =           9.34 m
Udl due to Live load( Load intencity) =           9.97 Kn/m2
Max.Vertical Load case
Longitudinal Dispersion =           6.27 m
Tranverse dispersion =           7.57 m
Udl due to Live load( Load intencity) =         16.22 Kn/m2
Calcualtion of Temperature Gradient in Top Slab
Temperature Rise Case:-
The top slab is designed for the effects of the distribution of the temperature across the deck depth as given in the sketch below:-
               
      Depth of Super-structure h =           0.85 m
Parameter       =    
      Grade of Cocnrere M =         30.00  
      Elastricity for Concrete E1 = 3.10E+06 T/m2
      Modified Elastricity for concrete' Ec=E1 = 3.10E+06 T/m2
      Co-efficient of Thermal Expansion a = 1.20E-05 /oC
               
Output              
        Stress = E.a.t  
        Force = F1+F2+F3  
        Moment = F1*x1+F2*x2-F3*x3

Temperature Rise Case:-                        
      Members Description h h1 h2 h3 T1 T2 T3 h1 0.3h<0>  Which is minimum
      (m) (m) (m) (m) oC oC oC h2 0.1<0>0.25  Which is minimum
        Top Slab          0.85 0.15          0.18 0.15 17.8 4 2.1 h3 0.3h<0>  Which is minimum
                               
      Members Description E.a.t
S1		 E.a.t
S2		 E.a.t
S3		 F1 F2 F3 F      
            (T/m2) (T/m2) (T/m2) (T) (T) (T) (T)      
        Top Slab     662.16   148.80       78.12 60.822 13.392 5.859 80.073      
Members Description CG of Section from Top CG of Section from bottom CG of top Block  from Top CG of Mid Block  from Top CG of bottom Block  from  bottom X1 X2 X3 M
      m m m  T-m 
  Top Slab 0.425 0.425     0.0592   0.2100    0.0500      0.366   0.215   0.375         22.93
Temperature fall  Case:-
      Depth of Super-structure h =           0.85 m
Parameter       =                -    
      Grade of Cocnrere M =         30.00  
      Elastricity for Concrete E1 = 3.10E+06 T/m2
      Modified Elastricity for concrete' Ec=E1 = 3.10E+06 T/m2
      Co-efficient of Thermal Expansion a = 1.20E-05 /oC
               
Output              
        Stress = E.a.t  
        Force = F1+F2+F3+F4
        Moment = F1*x1+F2*x2-f3*x3-F4*x4

Members Description h h1 h2 h3 h4 T1 T2 T3 T4 h1=h4 0.2h<0>  Which is minimum
      (m) (m) (m) (m) (m) oC oC oC oC h2=h3 0.25h<0>  Which is minimum
  Top Slab        0.85          0.17     0.213          0.21        0.17 10.6 0.7 0.8 6.6      
                             
Members Description E.a.t
S1		 E.a.t
S2		 E.a.t
S3		 E.a.t
S4		 F1 F2 F3 F4 F      
      (T/m2) (T/m2) (T/m2) (T/m2) (T) (T) (T) (T) (T)      
  Top Slab    394.32       26.04     29.76     245.52     35.73 2.76675         3.16   23.40   65.06      
  Members Description CG of Section from Top CG of Section from bottom CG of top Block  from Top CG of Mid Block  from Top CG of Mid Block  from bottom CG of bottom Block  from  bottom X1 X2 X3 X4 M
        m m m m  T-m 
    Top Slab 0.425 0.425     0.0602   0.2408    0.2408    0.0628   0.365   0.184         0.184      0.362    4.49
Result for 1 m fill above the deck
Bending Moment Envelope
  1. Bottom Slab :
  • Mid 

 MZ-top      : 801.03 kN-m

MZ-Bottom : 0.00 kN-m

  1. Bottom Slab :
  • Support Location

 MZ-top      : 311.118 kN-m

MZ-Bottom : 667.506 kN-m

Diagram :-

  • 3D Rendering View:

  • Deflection Diagram:-

3.(b). 1 m fill on top of the Bridge:

Bottom Slab Only:

Max.Bending Moment  values with diagram:

Mid location:

MZ top  : 641.2 kN-m

MZ bottom : 0 kn-m

Support Location:

MZ top  : 287.2 kN-m

MZ bottom : 422.71 knN-m

Bottom Slab Only:

Max.Shear force  values with diagram:

Mid location:

Fy   : 0 kN

Support Location:

Fy   : 389 kN

3.(a). 5 m fill on top of the Bridge:

Bottom Slab Only:

Max.Bending Moment  values with diagram:

Mid location:

MZ top        : 1.5E+03 kN-m

MZ bottom : 0 kn-m

Support Location:

MZ top        : 694.22 kN-m

MZ bottom : 927.9 knN-m

Bottom Slab Only:

Max.Shear force  values with diagram:

Mid location:

Fy   : 0 kN

Support Location:

Fy   : 884.55 kN

Bottom Slab Calculation:

Simple Calculation For Member
  Model Calcualtionvfor Member  9,10          
  Maximum Bending Moment under Basic Combination     = 801.03 kN-m
  Maximum Shear Force       VNS = 389.31 kN
  Depth of member         D =                            850.00 mm
  Width of Member         b = 1000 mm
  Grade of Concrete           = M 30  
  Grade ofSteel           = Fe 500  
  Characteristic strength of concrete     fck = 30 Mpa
  Characteristic strength of Steel       fy = 500 Mpa
  tensile Strength of Concrete       fctm =                                2.50 Mpa
  Design Yield strength of shear reinforcement     fywd =                                 348 Mpa
  Partial safety factor for concrete       gm = 1.5 Basic
  Partial safety factor for Steel       gs = 1.15 Basic
  Ultimate concrete strain in the concrete     <!-- [if gte vml 1]> Bitmap <![endif]--><!-- [if !vml]--><!--[endif]-->
 
= 0.0035  
  Modulus of Elasticity of reinforcing of steel     Es = 2.00E+05  
  Modulus of Elasticity of Concrete     Ecm = 3.10E+04  
  Moduler Ratio (Es/Ecm)   <!-- [if gte vml 1]> Bitmap Bitmap Bitmap Bitmap <![endif]--><!-- [if !vml]-->
       
   
 
 
<!--[endif]-->
 
    =                                6.45  
   Long term Moduler Ratio (Es/Ecm)       = 12.90  
  Ultimate tensile strain in the steel       = 2.17E-03  
  Co-efficient to consider the influence of the concrete strength   a = 0.67 Cube
  Factor         𝜆 = 0.8  
  0.8 up to fck<= 60Mpa, Eq.A2-33;IRC:112-2011;0.8-((fck-60)/500) for 60        
  Factor           = 1  
  1.0 up to fck<= 60Mpa, Eq.A2-35;IRC:112-2011;0.8-((fck-60)/250) for 60        
  Design value of concrete compressive strength     fcd = 13.4  
  Factor <!-- [if gte vml 1]> Bitmap Bitmap <![endif]--><!-- [if !vml]-->
       
 
 
 
 
<!--[endif]--><!-- [if !mso & vml]><![endif]-->		     Fav = 10.72  
  Factor     β = 0.4  
  Effective depth of the member     d =                            790.00 mm
  Kav=M/bd2*Fav         Kav =                              0.120  
  Limiting Neutral axis depth        Xu,lim =                            487.32  
            Xu,lim/d =                              0.617  
  We Know           =    
    Compressive Force= Tensile Force     =    
    fy*Ast/gs=Fav*x*b       =    
    Ast = Fav*x*b*gs/fy   =    
                   
    Moment = fy*Ast/gs)*(d-𝜆*x/2)      
    M = Fav*x*b*(d-βx)        
    M/Fav*b = x*(d-βx)     <!-- [if gte vml 1]> Bitmap <![endif]--><!-- [if !vml]--><!--[endif]-->
 
   
    74722.948 = x*(545-0.4x) x/d =    
                   
            x/d   0.126 Ok
            x =                              99.61 Ok
                   
    Required Reinforcement     Ast =                        2,473.07  
  provided Reinforcement              
  20 mm Dia. of Bar Spacing @ 200 mm c/c     Ast,provd =                        3,141.59  
                   
    Neutral Axis depth     x =                            126.54 Ok
  Limiting Neutral axis depth        Xu,lim =                         487.318  
            Xu,lim/d =                              0.617  
  Limiting Moment   Rlim = M/bd2 Rlim =                                5.02  
                   
  Required Effective depth       deff.required =                            399.53  
  Provided Effective depth       deff.provided =                            790.00 Ok

ULS Strength Check:

ULS                              
              issue                
Section Face Mdes(kN.m) Depth of NA(mm) Deff.reqd.
(mm)		 Doverall provd.
(mm)		 Deff.provd.
(mm)		 Ast.reqd.
(mm2/m)		 Bar Mark Dia. Of Bar Spacing Bar Mark Dia. Of Bar Spacing Ast.Provd.
(mm2/m)		 <!-- [if gte vml 1]> Bitmap <![endif]--><!-- [if !vml]--><!--[endif]-->
(% of Steel)
  Top            77.61           -   600 542                     -   ts1 16 200  ts7               -   200        1,005          0.17
Btm.          118.38           -   600 540                     -   ts3 20 200  ts6              16 200        2,576          0.43
  Top          134.18           -   600 538                     -   w1 25 200  ts1              16 200        3,460          0.58
Btm.            94.97           -   600 540                     -   ts3 20 200                  -                -   200        1,571          0.26
  Outside          144.54           -   700 613                     -   w1 25 200  ts1              16 200        3,460          0.49
Inside            85.00           -   700 642                     -   w2 16 200  w5               -   200        1,005          0.14
  Outside          124.34           -   700 613                     -   w1 25 200                  -                -   200        2,454          0.35
Inside          116.74           -   700 642                     -   w2 16 200  w5              16 200        2,011          0.29
  Outside          124.34           -   700 613                     -   w1 25 200  bs3               -   200        2,454          0.35
Inside            85.00           -   700 642                     -   bs1 16 200                  -                -   200        1,005          0.14
3,4 Top          101.97           -   700 615                     -   bs1 20 200                  -                -   200        1,571          0.22
Btm. 667.506        144.54  364.71 700 613        2,718.37 w1 25 200  bs3         16.00 200        3,460          0.49
9,10 Top 801.03        154.27  399.53 700 613        3,318.56 bs1 25 200  bs5         20.00 200        4,025          0.58
Btm.            83.21           -   700 617                     -   bs3 16 200  bs6               -   200        1,005          0.14
                               
Distribution Steel 20% of main reinforcement, Cl.16.6.1,IRC 112-2011                    
Section Face Doverall provd.
(mm)		 Deff.provd.
(mm)		 Ast.reqd.
(mm2/m)		 Bar Mark Dia. Of Bar Spacing Bar Mark Dia. Of Bar Spacing Ast.Provd.
(mm2/m)		 <!-- [if gte vml 1]> Bitmap <![endif]--><!-- [if !vml]--><!--[endif]-->
(% of Steel)
     
Top Slab Top 600 526  691.94 ts2 12 125                  -   150              905          0.17      
Btm. 600 526  515.22 ts4 12 125                  -   150              905          0.17      
Wall Inside 700 601  691.94 w3 12 125                  -   150              905          0.15      
Outside 700 601  314.16 w4 12 125                  -   150              905          0.15      
Bottom Slab Top 700 601  805.03 bs2 12 125                  -   150              905          0.15      
Btm. 700 601  805.03 bs4 12 125                  -   150              905          0.15      
                               
Check for Shear as per IRC:112-2020                          
Note: Shear force due to live load is not considered because live load is dispersed by effective width method            
Section Vdes Axial comp. Force(kN) Doverall provd.
(mm)		 Deff.provd.
(mm)		 Ast,provided
(mm2/m)		 Shear Resistance of Concrete Status Dia. Of Bar No. of Legs Spacing if required          
Top Slab                       -   600 550        3,460         241.02 Not reqd 12           2.00           200          
Wall                       -   700 650        3,460   Required 12           2.00           200          
Bottom Slab             389.31            232.00 700 625        3,460   Required 12           2.00           200          
  • Check for Stress of  the SLS Rare combinaton:
Design of Box- Serviceability Limit State(SLS)              
Permissible Stress in Concrete     = 14.4 Mpa Cl.12.2.1,IRC:112-2020,P-100
Permissible Stress in steel       = 400 Mpa Cl.12.2.2,IRC:112-2020,P-100
Section Face Mdes(kN.m) Depth of NA(mm) Doverall provd.
(mm)		 Deff.provd.
(mm)		 Ast.Provd.
(mm2/m)		 max.Compressive Stress in Concrete Mpa Status max. Tensile Stress in Steel Mpa Status
  Top                  78 600 542           1,005                     -   Ok                -   Ok
Btm.                118 600 540           2,576                     -   Ok                -   Ok
  Top                134 600 538           3,460                     -   Ok                -   Ok
Btm.                  95 600 540           1,571                     -   Ok                -   Ok
  Outside                145 700 613           3,460                     -   Ok                -   Ok
Inside                  85 700 642           1,005                     -   Ok                -   Ok
  Outside                124 700 613           2,454                     -   Ok                -   Ok
Inside                117 700 642           2,011                     -   Ok                -   Ok
  Outside                124 700 613           2,454                     -   Ok                -   Ok
Inside                  85 700 642           1,005                     -   Ok                -   Ok
3,4 Top 0              102 700 615           1,571                     -   Ok                -   Ok
Btm. 566.351              145 700 613           3,460            13.887 Ok       290.08 Ok
9,10 Top 662.57              154 700 613           4,025            15.309 Not Ok       293.38 Ok
Btm. 8                83 700 617           1,005              0.326 Ok         13.50 Ok
  • Check for Crack width of the SLS Quasi-Permanent combinaton:
Design of Box- Serviceability Limit State(SLS)                    
Permissible Crack Width     = 0.3 mm              
Section Face Mdes(kN.m) Depth of NA(mm) Doverall provd.
(mm)		 Deff.provd.
(mm)		 Ast.Provd.
(mm2/m)		 Max.Compressive Stress in Concrete Mpa Status Max. Tensile Stress in Steel Mpa Status Equivalent Dia. Crack Width Status
  Top                106 600 542           1,005                     -   Ok                -   Ok           16.00          0.20 Ok
Btm.                159 600 540           2,576                     -   Ok                -   Ok           18.22        -0.12 Ok
  Top                179 700 538           3,460                     -   Ok                -   Ok           21.49        -0.11 Ok
Btm.                129 700 540           1,571                     -   Ok                -   Ok           20.00        -0.44 Ok
  Outside                193 700 613           3,460                     -   Ok                -   Ok           21.49        -0.11 Ok
Inside                117 700 642           1,005                     -   Ok                -   Ok           16.00        -0.51 Ok
  Outside                168 700 613           2,454                     -   Ok                -   Ok           25.00        -0.22 Ok
Inside                158 700 642           2,011                     -   Ok                -   Ok           16.00        -0.17 Ok
  Outside                168 700 613           2,454                     -   Ok                -   Ok           25.00        -0.22 Ok
Inside                117 700 642           1,005                     -   Ok                -   Ok           16.00        -0.51 Ok
3,4 Top 0              139 700 615           1,571                     -   Ok                -   Ok           20.00        -0.43 Ok
Btm. 549.431              193 700 613           3,460            16.783 Not Ok       234.59 Ok           21.49          0.30 Not Ok
9,10 Top 662.576              206 700 613           4,025            18.929 Not Ok       241.70 Ok           22.78          0.31 Not Ok
Btm. 0              114 700 617           1,005                     -   Ok                -   Ok           16.00        -0.85 Ok
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