Ductile Design

Considering the flexural capacity of reinforced concrete beam and column, automatically design beam and column members.

The process of automatic design is outlined as below.

Step 1: Apply “Special Provisions for Seismic Design” for the design of beam members

Step 2: Calculate design member forces of column members (Calculate end moments that result in hinges at beam ends)

Step 3: Using the member forces and axial forces calculated from Step 2, perform automatic design for column members

Note
This function becomes activated when the following conditions arise:

1. Applied design codes: ACI318-89/95/99/02, TWN-USD92, KCI-USD99, KCI-USD03

2. When “Special Provisions for Seismic Design” is applied

From the Main Menu select Design > RC Strong Column-Weak Beam > Ductile Design.

The details of each item for Strong Column Design and Weak Beam Design are identical to those for general beam/column design.

TWN-USD92 Weak Beam Design Result dialog box

Weak Beam Design Results

MEMB: Member number

SECT: Section property number

Span: Length of beam member

SEL: Select members for redesign and production of results

Note
Use Spacebar Key to select or cancel.

Section: Section Name

Bc, Hc: Width, height (depth) of beam member

bf, hf: Width, thickness of the flange of T-shape section

fck: Design compressive strength of concrete

fy: Design yield strength of main rebars

fys: Design yield strength of shear rebars

POS: Automatic design positions (I, M, J)

The design results for M reflect the automatic design for the maximum negative and positive moments and shear forces at 1/4, 1/2 & 3/4 points.

CHK: Status of automatic design results (Results are produced in the state for convenience)

= "OK": Automatic design results satisfy the design strength for the factored negative moment, positive moment and shear force

= "N**": Automatic design results do not satisfy the design strength for the factored negative moment

= "*P*": Automatic design results do not satisfy the design strength for the factored positive moment

= "**V": Automatic design results do not satisfy the design strength for the factored shear force

= "NP*": Automatic design results do not satisfy the design strength for the factored negative and positive moments

= "*PV": Automatic design results do not satisfy the design strength for the factored positive moment and shear force

= "N*V": Automatic design results do not satisfy the design strength for the factored negative moment and shear force

= "NPV": Automatic design results do not satisfy the design strength for the factored negative moment, positive moment and shear force

N(-)Mu, LCB: Maximum factored negative moment occurring in the relevant member or section and the corresponding load combination

AsTop: The area of required to rebars calculated by the program. The larger of the calculated rebar area and the minimum

rebar quantity specified in the codes is presented.

Rebar(AsTop): The required number of rebars using the standard sizes specified by the user is presented.

When the reinforcing placement requires more than 2 layers, place the rebars up to the second layer.

= for 1 rebar-layer ("xx-Dyy")

xx is the number of top rebars and yy is the standard rebar size designation

= for 2 rebar-layers ("xx-yy-Dzz")

xx is the number of upper layer top rebars, yy is the number of lower layer top rebars and zz is the standard rebar size

designation

P(+)Mu, LCB: Maximum factored positive moment occurring in the relevant member or section and the corresponding load

combination

AsBot: The area of required bottom rebars calculated by the program. The larger of the calculated rebar area and the minimum

rebar quantity specified in the codes is presented.

Rebar(AsBot): The required number of rebars using the standard sizes specified by the user is presented.

When the reinforcing placement requires more than 2 layers, place the rebars up to the second layer.

= for 1 rebar-layer ("xx-Dyy")

xx is the number of bottom rebars and yy is the standard rebar size designation.

= for 2 rebar-layers ("xx-yy-Dzz")

xx is the number of lower layer bottom rebars, yy is the number of upper layer bottom rebars and zz is the standard rebar size

designation.

Vu, LCB: Maximum factored shear force occurring in the relevant member or section and the corresponding load combination

AsV: Reinforcing steel section area required for the shear force calculated by the program. The larger of the calculated rebar

area and the minimum rebar quantity specified in the codes is presented.

Note
Reinforcing steel section area required for the shear force is displayed differently depending on the selected unit. When the applied unit is mm, cm or m, it is displayed as mm2/m, cm2/m or m2/m. When the applied unit is in or ft, it is displayed as in2/ft or ft2/ft.

Stirrup: The required rebar spacing based on AsV using the standard sizes for sub-rebars entered by the user

The following are displayed for Stirrup based on the automatic design results:

= "xx-Dyy@zzz"

xx is the number of stirrups, yy is the standard rebar size designation and zzz is the rebar spacing (unit: mm).

= "Failure": When the design shear strength Vs does not satisfy the Clause 7.3.3.(8) in TWN-USD92 (When an increase in

section is required)

TWN-USD92 Strong Column Design Result dialog box

Strong Column Design Results

MEMB: Member number

SECT: Section property number

SEL: Select members for redesign and production of results

Note
Use SpaceBar Key to select or cancel.

Section: Section Name

Bc, Hc: Width, height (depth) of column section

Height: Height of column member

fck: Design compressive strength of concrete

fy: Design yield strength of main rebars

fys: Design yield strength of shear rebars

CHK: Status of automatic design results (Results are produced in the state for convenience)

= "OK": Automatic design results satisfy the design strength for the factored axial force, moment and shear force

= "P**": Automatic design results do not satisfy the design strength for the factored axial force

= "*M*": Automatic design results do not satisfy the design strength for the factored moment

= "**V": Automatic design results do not satisfy the design strength for the factored shear force

= "PM*": Automatic design results do not satisfy the design strength for the factored axial force and moment

= "*MV": Automatic design results do not satisfy the design strength for the factored moment and shear force

= "P*V": Automatic design results do not satisfy the design strength for the factored axial force and shear force

= "PMV": Automatic design results do not satisfy the design strength for the factored axial force, moment and shear force

LCB: Load combination yielding the maximum factored load ratio determined from the P-M diagram. The program examines all

the load combinations and sectional locations of the relevant member or section property to find the maximum ratio.

Pu: Factored compression (tension) force acting on the column member under the load combination displayed in LCB

= Pu > 0: Compressive axial force acting in the member's axial direction

= Pu < 0: Tensile axial force acting in the member's axial direction

Rat-P: Ratio of the factored axial force ( ) to the design axial strength ( ). The ratio larger than 1.0 signifies that the

design strength is unsatisfactory even if the rebar quantity is increased to the maximum rabar ratio or the minimum rebar spacing for the relevant column section.

Mc: Factored bending moment in the column member under the load combination displayed in LCB. The value is calculated as follows:

Rat-M: Ratio of the factored bending moment ( ) to the design bending moment strength ( ). The ratio larger than 1.0 signifies that the design strength is unsatisfactory even if the rebar quantity is increased to the maximum rebar ratio or the minimum rebar spacing for the relevant column section.

Ast: The quantity of main rebars auto-calculated by the program. This is larger than the minimum rebars specified by the codes.

V-Rebar: Optimum rebar size and the number of rebars, which satisfy the design conditions (minimum rebar spacing,

minimum/maximum reinforcing steel ratios).

"n1 - n2 - Dxx(#xx)"

n1: number of main rebars, n2: number of rows of main rebars, Dxx: designated standard size of main rebars

Vu: Maximum factored shear force of the relevant member or section (The load combination number that results in the

maximum factored shear force is displayed in the summary and detail calculations.)

Rat-V: Ratio of the factored shear force ( ) to the design shear strength ( )

As-H: Reinforcing steel section area required for the shear force calculated by the program, with the lower bound being the

minimum rebar quantity specified in the codes.

H-Rebar: Shear rebar placement spacing expressed in terms of As-H using the sub-rebar standard sizes entered by the user.

The following are displayed for H-Rebar based on the automatic design results:

"Dxx @yyy": xx is the designated standard rebar size, yyy is the rebar spacing (unit: mm).

"Failure": When the design shear strength Vs does not satisfy the Clause 7.3.3(8) in TWN-USD92 (When an increase in section is required)

Common Control

	Display the applicable code for automatic design.
	Display the unit system selected by the user.
	Sorted by Member: Display the design results by individual members. Arrangement order is based on the 'Primary Sorting Option' shown below. Sorted by Property: Display the design results of the maximum factored negative and positive moments and shear forces by sectional locations representing all the members attributed to the relevant section property. Since the results do not pertain to a single member, MEMB (member number is "0". Once Property is selected, SEL controls all the members attributed to the same section properties.
	When automatic design results are produced by members, select an option whether to arrange the results on the basis of section numbers or member numbers in an ascending order.
	Update the rebar quantity for each property type in the rebar design data. The updated rebar data are used for strength verification.
	Select all members or cancel the selection of all members.
	Redesign the selected members. When the redesign is executed from the results displayed by section properties, all the members attributed to the same sections are included. This option can be used even when the rebar splice data is changed. Note When modifying the design parameters ('Modify Concrete Material', etc.) that can affect all the design results, this option cannot be used since the design results will be deleted.
	Display detail automatic design results. Display simplified automatic design results.
	Select the sectional location data to be included in the Detail output.
	Produce the automatic design results in summary calculations for the selected members. Note In all Design Result Dialogs & Code Checking Result Dialogs, the Graphic Reports can be saved in a batch.
	Produce the automatic design results in detail calculations for the selected members. Detail output is supported only in the design results 'Sorted by Member'.
	Produce the summary list of automatic design results for the selected members.
	All: Produce all the auto-designed results in the Design Results dialog box OK: From the auto-designed results, display only the design results that have met the design requirements (OK) in the Design Results dialog box NG: From the auto-designed results, display only the design results that have not satisfied the design requirements (NG) in the Design Results dialog box
	Check in the option to select and highlight the selected members in Model View.
	Close the dialog box.