Section 6: Columns for Multi-Column Bents
Anchor: #i1351845Materials
Use TxDOT Class C concrete (ƒ'c = 3.6 ksi) and design for Grade 40 reinforcing steel, but allow use of Grade 40 or Grade 60 in the plans. Higher concrete or steel strengths may be required in special cases.
Anchor: #i1351872Structural Analysis
Design is not necessary for round columns with the column diameter, typical reinforcement and recommended height limits shown in this figure, as long as the column spacing is between 10 feet and 18 feet. Use the following diameters with the corresponding superstructurers without analysis for axial and bending:
Slab spans -- 24 in.
Pan form spans -- 24 in.
Types A and B and C prestressed beam spans -- 30 in.
Types IV and VI prestressed beam spans and U-beam spans -- 36 in.
For other beam types, compare drilled shaft load to what would be expected using one of the preceding superstructures, and use a column diameter as appropriate.