Quade999
Civil/Environmental
- May 29, 2020
- 61
Hello,
In AASHTO under service loads, the reinforcement is required to be spaced less than that calculated using the following equation.
When using two layers of tension reinforcement, both reinforcing layers will contribute to the resistance of the section as shown below. From what I understand is that when you do this calculation you calculate the stress in the beam considering both layers of bars and then use the stress and the cover of the bars in the bottom layer to find your maximum allowable spacing of bottom layer bars. I assume this is the correct way?
What I find weird about this is that theoretically you could have a situation like shown below where you use large bars in the upper layer and small bars in the lower layer (not really a real scenario). And only bottom layer spacing needs to satisfy this requirement.
It just seems a little weird that it doesn't matter the size and spacing of the inside layers of bars when comparing to the outside layer for this equation.
In AASHTO under service loads, the reinforcement is required to be spaced less than that calculated using the following equation.
When using two layers of tension reinforcement, both reinforcing layers will contribute to the resistance of the section as shown below. From what I understand is that when you do this calculation you calculate the stress in the beam considering both layers of bars and then use the stress and the cover of the bars in the bottom layer to find your maximum allowable spacing of bottom layer bars. I assume this is the correct way?
What I find weird about this is that theoretically you could have a situation like shown below where you use large bars in the upper layer and small bars in the lower layer (not really a real scenario). And only bottom layer spacing needs to satisfy this requirement.
It just seems a little weird that it doesn't matter the size and spacing of the inside layers of bars when comparing to the outside layer for this equation.
