When we design columns in RCDC some times upper level columns have more reinforcement perhaps due to higher moments in upper storey . How to design columns so that lower storeys have equal or more reinforcement than upper level columns?
HiRCDC is a design software. it gets the forces form analysis software. So, the design is based on the forces (Axial , Moment and shear forces) available from analysis software. Column design is based on the axial forces and bending moment in the column. RCDC design the column for these axial force and moments.As explained in the earlier thread, reinforcement in upper level columns is might be due to lesser axial force and high moments in the column.We would suggest following option to get lesser reinforcement at upper columns,
As column design is based on forces available from analysis, we would suggest you to model the structure in such a way that it will give lesser reinforcement at upper floor
in RCDC even you get the higher reinforcement at upper floor, you can still copy and paste the higher reinforcement to columns having lesser reinforcement.
Answer Verified By: Abhijeet Gundaye
HOW WE CAN GET DESIGN CALCULATION OF THE FAIL COLUMN IN RCDC?
RCDC designs the column floor-wise. If percentage reinforcement required at a given level is more than the lower floor then it could be because of higher moment at that floor. Normally this happens at terrace floor where moments are more as compared to lower floors. This can be checked as per efficiency ratios in the design table.
The average stress in column Pu/Ag for Pu-max from seismic load combinations, shall not exceed 0.4 x Fck. In this case RCDC will report this as a ‘Failure’ condition.