Calculate missing rebar development length, stress, or bond stress from any 3 values, including nominal diameter and design load stress, with units.
Development Length Formula
The following formula is used to calculate the Development Length.
DL = D*S / (4*BS)
- Where DL is the Development Length ( )
- D is the nominal diameter of the rebar
- S is the stress in bar at design load
- BS is the design bond stress
To calculate a development length, multiply the nominal diameter of rebar by the stress in the bar at design load, then divide by 4 times the design bond stress.
How to Calculate Development Length?
The following two example problems outline the steps and information needed to calculate the Development Length.
Example Problem #1
- First, determine the nominal diameter of the rebar.
- The nominal diameter of the rebar is calculated to be : 2.5.
- Next, determine the stress in bar at design load.
- The stress in bar at design load is measured to be: 2000.
- Next, determine the design bond stress.
- The design bond stress is found to be: 1500.
- Finally, calculate the Development Length using the formula above:
DL = D*S / (4*BS)
The values provided above are inserted into the equation below and computed.
DL = 2.5*2000 / (4*1500) = .833
Example Problem #2
The variables required for this problem are provided below:
nominal diameter of the rebar = 3
stress in bar at design load = 1000
design bond stress = 5000
Test your knowledge using the equation and check your answer with the calculator.
DL = D*S / (4*BS) = ( )
