**Estimating Reinforcements for a Concrete Footing**

Independent footing, also known as isolated footing, is a type of foundation attached to a single column and is the simplest and most common type of foundation. According to the plan and design of the footing, reinforcement for this footing can either be plain or have bends and hooks.

**HOW TO CALCULATE FOR QUANTITY OF STEEL BARS FOR A CONCRETE INDEPENDENT FOOTING:**

- Determine the length, width and underground protective covering of your concrete footing:
- Determine the cut length of one reinforcement bar:
- Determine the steel bar commercial length to be used and the number of cuts that can be made per steel bar:
- Determine the specified bar spacing or, if already provided, the number of bar cuts of your footing:
- Get the number of steel bars to be ordered:

Determine the following information based on the design of the your concrete footing.

From the information gathered, get the cut length of footing reinforcement bar. If the dimensions of the footing's length and width are different, get both cut lengths.

_{L}= Footing Length - (Underground Protective Covering * 2)

_{W}= Footing Width - (Underground Protective Covering * 2)

Steel bars are usually commercialy available in five(5) lengths: 6m, 7.5m, 9m, 10.5m and 12m. In order to calculate the quantity of steel bars to be ordered, we need to determine how many cuts can be made in a piece of steel bar.

_{L}

_{W}

**If the quotient is not a whole number, it means the commercial length selected is not divisible with the cut length. This will result in extra cuts. In order to avoid excess cuts, select a commercial length that is divisible by the cut length.**

For example, if your cut length is 2.5 meters, a 6 meter long steel bar will produce an excess cut of 1 meter.

However, if you select a 7 meter long steel bar, no excess cuts will be produced.

Unless specified in the drawings, the total number of bar cuts you will need for the footing will depend on the specified spacing of the footing.

_{L}= (Footing Length / Specified Bar Spacing) + 1

_{W}= (Footing Width / Specified Bar Spacing) + 1

_{L}= Total Number of Cuts

_{L}/ No. of Cuts Per Steel Bar

_{L}

_{W}= Total Number of Cuts

_{W}/ No. of Cuts Per Steel Bar

_{W}

**Total of Steel Bars to be ordered = Number of Steel Bars**

_{L}+ Number of Steel Bars_{W}**SAMPLE PROBLEM 1**

Compute for the quantity of steel bars needed for an independent footing that is 1500mm long and 1000mm wide, with the following given specification:

Bar Spacing = 200mm O.C.

**SOLUTION**

- Determine the length, width and underground protective covering of your concrete footing:
- Determine the cut length of one reinforcement bar:
- Determine the steel bar commercial length to be used and the number of cuts that can be made per steel bar:
- Determine the specified bar spacing or, if already provided, the number of bar cuts of your footing:
- Get the number of steel bars to be ordered:

Footing Width = 1000mm

Protective Cover = 75mm

**Cut Length**= Footing Length - (Underground Protective Covering * 2)

_{L}**= 1350mm**

**Cut Length**= Footing Width - (Underground Protective Covering * 2)

_{W}**= 850mm**

**No. of Cuts Per Steel Bar**= Steel Bar Commercial Length / Cut Length

_{L}

**= 4.44 ~ 4 pcs. per 6m steel bar**

**No. of Cuts Per Steel Bar**= Steel Bar Commercial Length / Cut Length

_{W}

**= 7.05 ~ 7 pcs. per 6m steel bar**

**Total Number of Cuts**= (Footing Length / Specified Bar Spacing) + 1

_{L}**= 8.5 ~ 8 pcs. of 850mm long steel bars**

**Total Number of Cuts**= (Footing Width / Specified Bar Spacing) + 1

_{W}**= 6 pcs. of 1350mm long steel bars**

**Number of Steel Bars**= Total Number of Cuts

_{L}_{L}/ No. of Cuts Per Steel Bar

_{L}

**= 2 pcs. of 6m long steel bars are needed.**

**Number of Steel Bars**= Total Number of Cuts

_{W}_{W}/ No. of Cuts Per Steel Bar

_{W}

**= 0.85pc. ~ 1 pc. of 6m long steel bars are needed.**

**Total of Steel Bars to be ordered**= Number of Steel Bars

_{L}+ Number of Steel Bars

_{W}

**= 3 pcs. of 6m long steel bars.**

Is this article useful? Let us know by following us on Facebook and sharing this article with the hashtag #veriaconcyclopedia

"The Lord makes firm the steps of the one who delights in him;

though he may stumble, he will not fall, for the Lord upholds him with his hand."

Psalm 37:23-24 (NIV)