Construction Industry/Barbending schedule

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Expert: - 7/5/2010


Question
Q. The answer of my question is as under give by you.I need more explanation on it if possibe because when I apply this rule with 2nd example, the answer does not meet with your answer that is 66.36". please help me on this issue.

Ans. The total length will be equal to the sum of the three straight sections plus the portion of a circle used to bend the rod.  Assuming you bend the rod around a 2" diameter post the calculation is:

A 2" diameter post equals 1" radius plus the 1" bar to be bent.  That's 2" plus the 4" L at each end and the 56" between the L's (60" minus 4").  The bend is 1/4 of the circumference for a 90 degree bend.  That's 2.36" at the center of the curve.  A sum is 4" + 2.36" + 56" + 2.36" + 4".  That adds up to 68.72" or 3.28" short of a 6' piece.

The length will change depending on the size of the bending post. Using the same calculations, a 1" bending post will reduce the total length to 66.36".

Answer
Hello Muhammad

Following is an explanation of calculating the length of rebar as in your example:

Circumference of the post = 3.1416 X Diameter.  Diameter = 2"   THEREFORE C= 6.2832          

Therefore 6.2832 divided by 4 (90 degree) = 1.5708".  (Bending a 1" diameter bar 90 degrees)      

Add 1/2 of the bar diameter or 1/2" (.5")                        

Dimension of bend at center of steel = 2.0708                        

THE CENTERLINE LENGTH IS MORE ACCURATE THAN CALCULATING THE NOMINAL LENGTH.  ADD TO THE TOTAL LENGTH OF THE STRAIGHT PORTIONS OF A BAR THE DIMENSION OF EACH BEND.  THEREFORE THE LENGTH OF A BENT REBAR IS AS FOLLOWS:
  1st LEG      4"                  
  1st BEND      2.0708"                  
  CENTER LEG           59.8584"                  
  2nd BEND      2.0708"   
  2nd LEG      4"   
       TOTAL       72" LENGTH AT CENTER OF REBAR

If the dimension of the Center Leg is 56" then the total is 68.1416"

If the bend is only 45 degrees, the length of the arc is the circumference divided by 8.

If you "round up or down" the numbers above equals 72.2"
Round up using the 56" center measurement equals 68.2"

I'm sorry my first answer was confusing.  I hope this is adequate.

Roger
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Roger Zona

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I am experienced in all types of construction: residential, industrial and commercial; single family, multi-family, mid-rise and high rise buildings (16 story office building) as well as remodeling, additions and tenant improvements. I can field most any question that relates to general construction. I have consulted with infrastructure (utility) contractors also and have a good general knowledge of underground utility construction for subdivisions and commercial projects.

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After college, I began my career in the construction industry. I chose to become an apprentice Architect and 4 yrs later I opened my own architectural design firm. Six years later I moved to Florida to buy & develop land and build. I became a State of Florida Certified General Contractor and operated my business for 45 years. I built all types of residential and commercial buildings including warehouses, shopping centers, high rise apartments and office buildings and developed sites for other contractors. I retired and became a consultant to the construction industry. I maintain my license and continuing education requirements, operate a small construction company and write a weekly newspaper column for the Palm Beach Post (a Cox publication) with the byline "Ask The Contractor". I am the "technical editor" for a publisher of books that relate to home maintenance.

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Previously - NAHA Currently - FLCA (Florida Licensed Contractors Assoc.)

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Palm Beach Post newspaper - weekly Q & A column Happy Herald monthly real estate publication - monthly column

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Michigan State University University of Detroit BS in Engineering

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I built a home in Palm Beach for a member of the Pulitzer Family. I was responsible for the completion of a twin hi-rise condominium project for G.E. Credit. I was a partner in the successful development of a P.U.D. (Planned Urban Development) subdivision. I represented the largest home builder from France (Bati Service, S.A.) in the development of a subdivision and the design and construction of the homes.

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