D1.F.3 Design Parameters

The following outlines the parameters that are available to control the design of members as beams or columns per the ACI 318-14 code. The commands that initiate the design of these is outlined in TR.53.3 Concrete Design Command. If any parameter is not specified and its value is required in the design, then it will use that specified as the default value in the tables below.
Table 1. ACI 318 Design Parameters
Parameter Name Default Value Description
BDY 1.0 Column stiffness reduction factor for bending about the local Y axis.
BDZ 1.0 Column stiffness reduction factor for bending about the local Z axis.
BRDO 0 Bottom Rebar Detail Options
  • 0) Increase number of bars, then increase bar size, then add layers
  • 1) Increase the bar size, then increase the number of bars, then add layers
CLB

1.5 in. (38 mm) for members*

Minimum cover from the base of the section to the bottom longitudinal reinforcement.
CLS 1.5 in. (38 mm)* Minimum cover from the sides of the section to the side longitudinal reinforcement.

See Note a and Note c below.

CLT

1.5 in. (38 mm) for members*

Minimum cover from the top of the section to the top longitudinal reinforcement.
CRDO 0 Design options for main reinforcement in columns
  • 0) Increase the number of bars and the bar size
  • 1) Increase the bar size and then the number of bars
FC 4,000 psi (28 N/mm2)* Compressive strength of concrete.
FYMAIN 60,000 psi (420 N/mm2)* Yield stress for main longitudinal reinforcing steel.
FYSEC 60,000 psi (420 N/mm2)* Yield stress for transverse reinforcing steel.
LATR 0 (No) Is this member subject to lateral loading?
  • 0) No
  • 1) Yes
This will be used in determining the development length requirements, in ACI 318-14 clause 9.7.3.8. This parameter is only applicable for beams.
LWF 0 Specifies the aggregate composition of the concrete.
  • 0) Normal weight
  • 1) Sand light weight
  • 2) All light weight
MAXMAIN #18 (Imperial), 57M (Metric)

Maximum size of reinforcing bar to be used for longitudinal reinforcement.

MIMB #4 (Imperial), 13M (Metric) Minimum main rebar number (size) at the bottom face
MIMS #4 (Imperial), 13M(Metric) Minimum main rebar number (size) at for skin (side) bars
MIMT #4 (Imperial), 13M (Metric) Minimum main rebar number (size) at the top face
MINMAIN #4 (Imperial), 13M (Metric)

Minimum size of reinforcing bar to be used for longitudinal reinforcement.

MINSEC #4 (Imperial), 13M (Metric) Minimum size of reinforcing bar to be used for transverse reinforcement.
MMAG 1.0 Factor to magnify the analysis moments used for column design.
MXMB #18 (Imperial), 57M (Metric) Maximum main rebar number (size) at the bottom face
MXMS #18 (Imperial), 57M (Metric) Maximum main rebar number (size) for skin (side faces) bars
MXMT #18 (Imperial), 57M (Metric) Maximum main rebar number (size) at the top face
RCOAT 0 Rebar coating type:
  • 0) No coating
  • 1) Epoxy coating
  • 2) Galvanized
REINF 0

Column transverse reinforcement type.

  • 0) links (tied column)
  • 1) spiral reinforcement
RHOMIN 0.01 Minimum reinforcement required in a concrete column. Enter a value between 0.0 and 0.08, where 0.08 = 8% reinforcement; the maximum allowed by the ACI code.
SKY 1.0 Effective length factor for moment magnification procedure calculations for columns, in the local Y direction. When the SWY parameter is 0 (i.e., not braced), then SKY ≥ 1.0. When SWY is 1 (i.e., braced), then 0.5 ≤ SKY ≤ 1.0.
SKZ 1.0 Effective length factor for moment magnification procedure calculations for columns, in the local Z direction. When the SWY parameter is 0 (i.e., not braced), then SKZ ≥ 1.0. When SWY is 1 (i.e., braced), then 0.5 ≤ SKZ ≤ 1.0.
SLY n/a

Number of the load case that applies sidesway load in the local Y axis for column design.

The moments from this case are used to magnify the local Y axis moments for all design load cases as per the sway or non sway requirements. Calculations are dependent on the SWY parameter setting.

SLZ n/a

Number of the load case that applies sidesway load in the local z axis for column design.

The moments from this case are used to magnify the local Z axis moments for all design load cases as per the sway or non sway requirements. Calculations are dependent on the SWY parameter setting.

SQY 0.2

Stability index, Q, in the local Y axis as defined in ACI 318 section 6.6.4.3(b).

SQZ 0.2

Stability index, Q, in the local Z axis as defined in ACI 318 section 6.6.4.3(b).

SWY 0

Braced against sidesway:

  • 0) Not braced
  • 1) Braced
TRACK 0.0
Output detail
  • 0) Design and report only the steel area requirements
  • 1) Perform detailed design and report bar layouts
  • 2) Perform detailed design and report all details
TRDO 0 Top Rebar Detail Options
  • 0) Increase number of bars, then increase the bar size, then add layers
  • 1) Increase the bar size, then increase the number of bars, then add layers
TRN 0 Specifies whether a member is subject to transverse loads between supports. This parameter influences the moment magnification calculations per CL 6.6.4.5.3.
  • 0) True
  • 1) False

Notes

  1. The value used when specifying the CLS parameter for column design is taken to be the clear cover for the longitudinal bars in a column. It is not taken as the clear cover for the tie bars. Therefore, the distance from the edge of the column to the centerline of the first row of longitudinal bars is CLS plus half the diameter of the main bar.
  2. The following parameters are not applicable to the ACI 318-14 (only to ACI 318-11 and earlier):
    • DEPTH
    • EFACE
    • RHOMAIN
    • SFACE
    • WIDTH
    • NSECTION
  3. MAXMAIN and MINMAIN are now supplemented by new set of parameters like MXMB, MIMC etc. You can assign values either in the old parameters (like MAXMAIN) or in the new parameters (like MXMT, MXMB, MXMC). If you choose to use older parameters like MAXMAIN and MINMAIN, the program will store this input into newer parameters like MXMB, MIMC etc. internally. However, if you use both older and newer parameters, only the newer parameter values are accepted by the program.