StruCalc’s footing design module allows for the design of square, rectangular and/or continuous footings.  The footing module will provide size and reinforcement requirements for any concrete footing loaded with pure vertical load.  After a footing type has been specified StruCalc will then want to know what is providing the load; this will mean specifying the column type for the square or rectangular footing, or the stemwall type for the continuous footing.

Here you can see the load selection criteria for square and rectangular footings:

Square or Rectangular Footing

And here you can see selecting a continuous footing allows for selecting the stemwall type and weight in pcf:

Continuous Footing

After the footing type has been entered it will then be appropriate to enter the loads on the footing.  The loads can come from two sources:  calculations elsewhere in the structure that might result in reactions from beams, columns, walls, etc., or they might come from the use of the load calculator.  The load calculator will generate loads on the footing based on user set floor, roof, and wall loads followed by specifying tributary widths or areas.

You can see the standard load inputs of Live Load and Dead Load above. Selecting the Load Calculator option gives you this calculator:

Footing Load Calculator

Simply filling in the load options in the calculator will automatically calculate the Live Load and Dead Load.

After the loads have been entered the there remains some additional footing/environment information that will need to be entered.  Steel yield strength, concrete compressive strength, soil bearing pressure, reinforcement cover, and reinforcement bar size will all need to be entered.  StruCalc preloads some common values for the above mention properties, but the user is free to change any that might not be accurate.  More information about the column would also need to be entered now when doing a square or rectangular footing design.

Now, when designing a square or rectangular footing StruCalc will require a depth and a trial footing width (and length for rectangular footing) to be entered.

 Rectangular Footing

After, they have been entered StruCalc will verify their adequacy as well as give the reinforcement requirements.  If the dimensions of the footing are inadequate a red bar will appear in the lower right hand corner of the screen and new dimensions will need to be entered.  It will be at this point though, that StruCalc will have calculated a required area for the footing.  This will allow the user to specify dimensions to satisfy the area required.

Square or Rectangular Footing Requirements

If the user is designing a continuous footing then the stemwall thickness and height, as well as the footing depth will all need to be entered.  After they have been entered StruCalc will generate a footing width required as well as the continuous reinforcement that is required.

Continuous Footing                        Continuous Footing Reinforcement Requirements                    Continuous Footing Requirements

For either of the three types of footings you can also add a soil weight load and it will compensate in the footing’s total load for the additional required load. You can select this option using the Calculate Soil Weight Above Footing as shown below:

Footing Soil Weight Load Addition

View All StruCalc Features

January 22, 2008

Footing Design Module