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AISC & ACI Base plate and Anchor rod verifications

BaseplateDG#1

Figure 1: Book 1

Information presented on this page is intended to demonstrate the section design convergence of 2005 AISC Specification for Structural Steel Buildings  provisions for Base Plate and Anchor Rod Design that can be achieved with SkyCiv. All examples are taken from the following references:

Book 1: James M. Fisher, Lawrence A. Kliober. Steel Design Guide 1. Base Plate and Anchor Rod Design (Second Edition), 2006.

The most significant results are compared in the table below:

Book 1 | Chapter 4.0 Design of Examples

Results
Examples skyCiv
LFRD
Manual
LFRD
skyCiv
ASD
Manual
ASD
1. Base Plate for Concentric Axial (No concrete confinement), t = 1.61 1.60 1.47 1.54
2. Base Plate for Concentrix Axail Compressive Load 1.49 1.50 1.49 1.50
 3. Available Tensile Strength of a 3/4 in. Anchor Rod 14.38 14.40 9.58 9.6
 4. Concrete Embedment Strength 19.4 19.5 NA NA
5. Column Anchorage for Tensile Loads
6. Small Moment Base Plate Design 1.35 1.36 1.39 1.39
7. Large Moment Base Plate Design 1.90 1.90 1.82 1.82
8. Shear Transfer Using Bearing 1.26 1.26 1.26 1.26
9. Shear Lug Design
10. Edge Distance for Shear 32.7 32.7 32.7 32.7
11. Anchor Rod Resisting Combined Tension and Shear 30.09 30.10 20.88 20.11

Book 1 | Appendix B

Results
Examples skyCiv
LFRD
Manual
ASD
skyCiv
LFRD
Manual
ASD
Triangular Pressure Distribution

 

 

Example # 1 Base Plate for Concentric Axial Compressive Load (No concrete confinement).

reference: Book 1, pp. 31.

DESCRIPTION
A W12x96 column bears on a 24-in x 24-in. concrete pedestal.
Determine the base plate dimensions and thickness for for the given required strength, using the assumption that A2 = A1 (Case I).

GEOMETRY AND MATERIAL PROPERTIES

 

Figure 2: Base Plate model and material properties of example #1

Detail Inputs (Geometry)
1. Steel Column d = 12.71 in bf = 12.16 in tw = 0.55 in tf = 0.90 in
2.  Plate N = 24 in B = 24 in
 3. Column (Pedestal) N2 = 24 in B2 = 24 in

 

LOADING
Two static loads cases are considered for LRFD and ASD:

INPUT LFRD ASD
MANUAL 700 kips 430 kips
SKYCIV 500 kips 430 kips

The results of service and factor load combination are in computed in reference of ASCE/SEI 7-10.

ANALYSIS

The analysis is done using the rigid conventional method. See the SkyCiv Base plate Manual for more explanation on using SkyCiv  Base Plate.

RESULT COMPARISON

The most significant results are compared in the table below:

Detail Results
Examples skyCiv
LFRD
Manual
LFRD
skyCiv
ASD
Manual
ASD
1. Required Base plate area 421.57 in2 422.00 in2 421.57 in2 422.00 in2
2.  inequality 729.30 kips 729.00 kips 448.80 kips 499.00 kips
 3. Base plate plate thickness 1.61 in 1.60 in 1.47 in 1.54 in

 

Example # 2 Base Plate for Concentric Axial Compressive Load (Using concrete confinement).

reference: Book 1, pp. 32.

DESCRIPTION
A W12x96 column bears on a 24-in x 24-in. concrete pedestal.
Determine the base plate dimensions and thickness for for the given required strength, using the assumption that A1 ≤ A2 ≤ 4A1 (Case III).

GEOMETRY AND MATERIAL PROPERTIES

Figure 2: Base Plate model and material properties of example #1

Detail Inputs (Geometry)
1. Steel Column d = 12.71 in bf = 12.16 in tw = 0.55 in tf = 0.90 in
2.  Plate N = 16 in B = 14 in
 3. Column (Pedestal) N2 = 24 in B2 = 21.6 in

 

LOADING
Two static loads cases are considered for LRFD and ASD:

INPUT LFRD ASD
MANUAL 700 kips 430 kips
SKYCIV 500 kips 430 kips

 

The results of service and factor load combination are in computed in reference of ASCE/SEI 7-10.

ANALYSIS

The analysis is done using the rigid conventional method. See the SkyCiv Base plate Manual for more explanation on using SkyCiv  Base Plate.

RESULT COMPARISON

The most significant results are compared in the table below:

Detail Results
Examples skyCiv
LFRD
Manual
LFRD
skyCiv
ASD
Manual
ASD
1. Required Base plate area 421.57 in2 211.00 in2 421.57 in2 211.00 in2
2.  inequality 729.30 kips 716.00 kips 448.80 kips 400.00 kips
 3. Base plate plate thickness 1.61 in 1.50 in 1.47 in 1.50 in

Example # 3 Available Tensile of 3/4-in Anchor Rod.

reference: Book 1, pp. 34.

DESCRIPTION
Computation the available tensile strength of a 3/4-in. diameter Anchor Rod using ASTM F1554 Grade 36.

GEOMETRY AND MATERIAL PROPERTIES

INPUT SKYCIV
Anchor rod code ASTM F1554 Grade 36
diameter 3/4in dia.

ANALYSIS

The analysis is done using the rigid conventional method. See the SkyCiv Base plate Manual for more explanation on using SkyCiv  Base Plate.

RESULT COMPARISON

The most significant results are compared in the table below:

Detail Results
Examples skyCiv
LFRD
Manual
LFRD
skyCiv
ASD
Manual
ASD
Tensile Strength 14.41  kips 14.40 kips 9.61 kips 9.6 kips

Example # 4 Concrete Embedment Strength

reference: Book 1, pp. 34.

DESCRIPTION
Calculating the tensile strength design of the concrete for a single smooth 3/4-in. diameter headed anchor rod with an embedment length of 6 in.

GEOMETRY AND MATERIAL PROPERTIES

INPUT SKYCIV
Concrete strength 4000 psi
diameter 3/4in dia.
hef 6 in

ANALYSIS

The analysis is done using the rigid conventional method. See the SkyCiv Base plate Manual for more explanation on using SkyCiv  Base Plate.

RESULT COMPARISON

The most significant results are compared in the table below:

Detail Results
Examples skyCiv
LFRD
Manual
LFRD
skyCiv
ASD
Manual
ASD
Tensile Strength 19.52 kips 19.50 kips N/A

Note: No equivalent ASD solution to this this check exist on ACI.

 

Albert Pamonag Structural Engineer, Product Development


Albert Pamonag
Structural Engineer, Product Development
B.S. Civil Engineering

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