RCDC L shape column design as per IS:456

Question

One of our would-be client wants to get a L shape RCC column design computation done in RCDC as per IS:456 for checking purpose. 
 If some readyment compuation for any size L shape column is availablepl share it.

Abhisek M · Answer

Hi, 
 I just quickly created a file with very basic details and load case with a L shape column. Please see if this helps. I believe you will be able to extract drawings and reports from the attached RCDC file. please let us know if you need any more info. 
 https://communities.bentley.com/cfs-file/__key/communityserver-discussions-components-files/5932/Structure1_2D00_Column_2D00_1.rcdx 3276.Structure1.STD

Royal Civil Design Center · Answer

clsRCDCInfo:RestoreProjectSchema - ERROR: 3F000: schema "AN_Frame_Assignments" does not exist

Royal Civil Design Center · Answer

General Data Column No. : C1 Level : 0m To 7.5m Design Code = IS 456 + IS 13920 - 2016 Grade Of Concrete = M25 N/sqmm Grade Of Steel = Fe415 N/sqmm Shape = L-Shape DF1 = 750 mm BF1 = 250 mm DF2 = 750 mm BF2 = 250 mm Outermost Lx = 750 mm Outermost Ly = 750 mm Clear Floor Height @ B = 7100 mm Clear Floor Height @ D = 7100 mm No Of Floors = 1 No Of Columns In Group = 1 Column Type : UnBraced Minimum eccentricity check : One Axis at a Time Code defined D/B ratio : 4 D/B Ratio : 1 <= 4 Hence, Design as Column Load Data Analysis Reference No. = 5 Load Combination = [1] : 1.5 (LOAD 1: LOAD CASE 1) +1.5 (LOAD 2: LOAD CASE 2) Critical Location = Top Joint Pu = 226.73 kN Mux = -18.65 kNm Muy = 18.65 kNm Vux = 3.36 kN Vuy = 3.36 kN Minimum Eccentricity Check Since Axial Force is compressive, Min. Eccentricity check to be performed Most critical case is with Min. Eccentricity check in X-direction Minimum Eccentricity Along Lx: Minimum Eccentricity = Unsupported Length / 500 + Lx / 30 = 39.2 mm Minimum Eccentricity > 20 mm Mminx = Pu x Minimum Eccentricity = 8.89 kNm Slenderness Check Max Slenderness Ratio(Lx/Ly) = 9.47 < 60 (Hence Ok) Column Is Unbraced Along Lx Slenderness Check Along Lx: Effective Length Factor = 1 Slenderness Ratio = Effective Length / Lx = 9.47, Column not Slender Along Lx Column Is Unbraced Along Ly Slenderness Check Along Ly: Effective Length Factor = 1 Slenderness Ratio = Effective Length / Ly = 9.47, Column not Slender Along Ly Calculation of Design Moment Direction Manalysis Mmin (Abs) Mdesign Mslndx (Abs) Mdesign-final A B C E F Major Axis - Mux -18.65 8.89 -18.65 0 -18.65 Minor Axis - Muy 18.65 --- 18.65 0 18.65 Where A = Moments directly from analysis B = Moments due to minimum eccentricity C = Maximum of analysis moment and min. eccentricity = Max (A,B) E = Moment due to slenderness effect F = Final design Moment = Max(C- Top Bottom , D- Top Bottom) + E Final Critical Design Forces Pu = 226.73 kN Mux = -18.65 kNm Muy = 18.65 kNm Resultant Moment (Combined Action) Moment Capacity Check Pt Calculated = 0.43 Reinforcement Provided = 12-T12 Load Angle = Tan -1 (Muy/Mux) = 225 deg MRes = 26.38 kNm MCap = 151.35 kNm Capacity Ratio = MRes/ MCap = 0.17 <= 1 Design Of Shear Design for shear along Lx Critical Load Combination = [1] : 1.5 (LOAD 1: LOAD CASE 1) +1.5 (LOAD 2: LOAD CASE 2) Design shear force, Vuy = 3.359 kN Pu = 226.73 Deff = 694 mm Design shear stress, Tvy = Vuy / (Lyx Deff) N/sqmm = 0.0124 N/sqmm Pt = 0.217 % Design shear strength, Tc = 0.343 N/sqmm Shear Strength Enhancement Factor = 1 + 3 x Pu / ( Ag x Fck) = 1.0871 Shear Strength Enhancement Factor (max) = 1.5 Shear Strength Enhancement Factor = 1.0871 Enhanced shear strength, Tc-e = 0.3728 N/sqmm Design shear check = Tvy < Tc x Enhancement factor Link for Shear Design along Lx are not required Design for shear along Ly Critical Load Combination = [1] : 1.5 (LOAD 1: LOAD CASE 1) +1.5 (LOAD 2: LOAD CASE 2) Design shear force, Vux = 3.359 kN Pu = 226.73 Beff = 694 mm Design shear stress, Tvx = Vux / (Lx x Beff) kN = 0.0124 N/sqmm Pt = 0.217 % Design shear strength, Tc = 0.343 N/sqmm Shear Strength Enhancement Factor = 1 + 3 x Pu / (Ly x Lx x Fck) = 1.0871 Shear Strength Enhancement Factor (max) = 1.5 Shear Strength Enhancement Factor = 1.0871 Enhanced shear strength, Tc-e = 0.3728 N/sqmm Design shear check = Tvx < Tc x Enhancement factor Link for Shear Design along Ly are not required Design Of Links Links in the zone where special confining links are not required Normal Links Diameter of link = 8 mm > Max. longitudinal bar dia / 4 = 3 mm Criterion for spacing of normal links Min. Longitudinal Bar dia X 16 = 192 mm Min. dimension of column = 750 mm Max. 300 mm = 300 mm Provided spacing = 175 mm Table For Links Required Provided Normal Design Shear Design Ductile Design Normal Zone Ductile Zone Link Dia. 8 --- --- 8 --- Spacing 175 --- --- 175 --- General Data Column No. : C1 Level : 7.5m To 15m Design Code = IS 456 + IS 13920 - 2016 Grade Of Concrete = M25 N/sqmm Grade Of Steel = Fe415 N/sqmm Shape = L-Shape DF1 = 750 mm BF1 = 250 mm DF2 = 750 mm BF2 = 250 mm Outermost Lx = 750 mm Outermost Ly = 750 mm Clear Floor Height @ B = 7100 mm Clear Floor Height @ D = 7100 mm No Of Floors = 1 No Of Columns In Group = 1 Column Type : UnBraced Minimum eccentricity check : One Axis at a Time Code defined D/B ratio : 4 D/B Ratio : 1 <= 4 Hence, Design as Column Load Data Analysis Reference No. = 8 Load Combination = [1] : 1.5 (LOAD 1: LOAD CASE 1) +1.5 (LOAD 2: LOAD CASE 2) Critical Location = Top Joint Pu = 70.72 kN Mux = -39.32 kNm Muy = 39.32 kNm Vux = 8.48 kN Vuy = 8.48 kN Minimum Eccentricity Check Since Axial Force is compressive, Min. Eccentricity check to be performed Most critical case is with Min. Eccentricity check in X-direction Minimum Eccentricity Along Lx: Minimum Eccentricity = Unsupported Length / 500 + Lx / 30 = 39.2 mm Minimum Eccentricity > 20 mm Mminx = Pu x Minimum Eccentricity = 2.77 kNm Slenderness Check Max Slenderness Ratio(Lx/Ly) = 9.47 < 60 (Hence Ok) Column Is Unbraced Along Lx Slenderness Check Along Lx: Effective Length Factor = 1 Slenderness Ratio = Effective Length / Lx = 9.47, Column not Slender Along Lx Column Is Unbraced Along Ly Slenderness Check Along Ly: Effective Length Factor = 1 Slenderness Ratio = Effective Length / Ly = 9.47, Column not Slender Along Ly Calculation of Design Moment Direction Manalysis Mmin (Abs) Mdesign Mslndx (Abs) Mdesign-final A B C E F Major Axis - Mux -39.32 2.77 -39.32 0 -39.32 Minor Axis - Muy 39.32 --- 39.32 0 39.32 Where A = Moments directly from analysis B = Moments due to minimum eccentricity C = Maximum of analysis moment and min. eccentricity = Max (A,B) E = Moment due to slenderness effect F = Final design Moment = Max(C- Top Bottom , D- Top Bottom) + E Final Critical Design Forces Pu = 70.72 kN Mux = -39.32 kNm Muy = 39.32 kNm Resultant Moment (Combined Action) Moment Capacity Check Pt Calculated = 0.43 Reinforcement Provided = 12-T12 Load Angle = Tan -1 (Muy/Mux) = 225 deg MRes = 55.61 kNm MCap = 126.19 kNm Capacity Ratio = MRes/ MCap = 0.44 <= 1 Design Of Shear Design for shear along Lx Critical Load Combination = [1] : 1.5 (LOAD 1: LOAD CASE 1) +1.5 (LOAD 2: LOAD CASE 2) Design shear force, Vuy = 8.4809 kN Pu = 70.72 Deff = 694 mm Design shear stress, Tvy = Vuy / (Lyx Deff) N/sqmm = 0.0314 N/sqmm Pt = 0.217 % Design shear strength, Tc = 0.343 N/sqmm Shear Strength Enhancement Factor = 1 + 3 x Pu / ( Ag x Fck) = 1.0272 Shear Strength Enhancement Factor (max) = 1.5 Shear Strength Enhancement Factor = 1.0272 Enhanced shear strength, Tc-e = 0.3523 N/sqmm Design shear check = Tvy < Tc x Enhancement factor Link for Shear Design along Lx are not required Design for shear along Ly Critical Load Combination = [1] : 1.5 (LOAD 1: LOAD CASE 1) +1.5 (LOAD 2: LOAD CASE 2) Design shear force, Vux = 8.4809 kN Pu = 70.72 Beff = 694 mm Design shear stress, Tvx = Vux / (Lx x Beff) kN = 0.0314 N/sqmm Pt = 0.217 % Design shear strength, Tc = 0.343 N/sqmm Shear Strength Enhancement Factor = 1 + 3 x Pu / (Ly x Lx x Fck) = 1.0272 Shear Strength Enhancement Factor (max) = 1.5 Shear Strength Enhancement Factor = 1.0272 Enhanced shear strength, Tc-e = 0.3523 N/sqmm Design shear check = Tvx < Tc x Enhancement factor Link for Shear Design along Ly are not required Design Of Links Links in the zone where special confining links are not required Normal Links Diameter of link = 8 mm > Max. longitudinal bar dia / 4 = 3 mm Criterion for spacing of normal links Min. Longitudinal Bar dia X 16 = 192 mm Min. dimension of column = 750 mm Max. 300 mm = 300 mm Provided spacing = 175 mm Table For Links Required Provided Normal Design Shear Design Ductile Design Normal Zone Ductile Zone Link Dia. 8 --- --- 8 --- Spacing 175 --- --- 175 ---

Abhisek M · Answer

In RCDC we calculate capacity of column through P-M diagram created for every column within the program. You will get the details of column design methodology here. 
 https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/44016/column-design-methods

Royal Civil Design Center · Answer

I am using both RCDC & STAAD.Pro seperate for L-shaped member property. 
 If you want I will send RCDC and STAAD.Pro files both or each. Which one you are using most?

Royal Civil Design Center · Answer

	Required			Provided
	Normal Design	Shear Design	Ductile Design	Normal Zone	Ductile Zone
Link Dia.	8	---	---	8	---
Spacing	175	---	---	175	---

	Required			Provided
	Normal Design	Shear Design	Ductile Design	Normal Zone	Ductile Zone
Link Dia.	8	---	---	8	---
Spacing	175	---	---	175	---