column with misaligned bars

[ticas]

How often do you encounter columns with misaligned main bars, for example, one corner has the bar 30mm from the corner while the other corner has bar that is 50mm from the corner. Originally they should be 40mm (meaning the surrounding concrete cover is 40mm), but in actual construction, it becomes 30mm and 50mm. The column is 500x500mm. In your experience, how big is the axial load moment capacity changes for these misaligned bars? What happens is the bars are not straight up and during construction, no concrete spacers was used in the upper formworks because they assume the bars are straight up.

 

[a7x1984]

"How big is the axial moment capacity changes..."

Why don't you just calculate the difference?

In Russia building design you!

 

[racookpe1978]

Where are the rest of the rods?

 

[hokie66]

This should not change appreciably the axial load capacity. Cover for durability would perhaps be a greater concern.

 

[ztengguy]

just re calculate with the different spacing, that will tell you the capacity diference. I cant believe it would be more than 5% for the 10 mm change. Let us know

 

[a7x1984]

Also, check the ACI 117 for construction tolerance allowances. Assuming the original design is good and all other construction aspects meet the design req., you are good to go.

In Russia building design you!

 

[par060]

chances are if you have designed a column before....you had a column you designed built where thew reinforcing was 10 mm off.....

 

[TXStructural]

If you design using ACI318, the tolerances listed in ACI 117 are part of the design assumptions included in the equations and factors. I'm certain other codes also include tolerances as part of the design methodology/criteria.