(Round up to the nearest inch.)

Similar documents
UNIVERSITY OF AKRON Department of Civil Engineering

Karbala University College of Engineering Department of Civil Eng. Lecturer: Dr. Jawad T. Abodi

General Comparison between AISC LRFD and ASD

MODULE C: COMPRESSION MEMBERS

2010 NASCC / Structures Congress Orlando, Florida May 13, 2010

ERRATA for PE Civil Structural Practice Exam ISBN Copyright 2014 (July 2016 Second Printing) Errata posted

ENCE 455 Design of Steel Structures. III. Compression Members

Compression Members. ENCE 455 Design of Steel Structures. III. Compression Members. Introduction. Compression Members (cont.)

Karbala University College of Engineering Department of Civil Eng. Lecturer: Dr. Jawad T. Abodi

Presented by: Civil Engineering Academy

Accordingly, the nominal section strength [resistance] for initiation of yielding is calculated by using Equation C-C3.1.

SUMMARY FOR COMPRESSION MEMBERS. Determine the factored design loads (AISC/LRFD Specification A4).

DNV DESIGN. POU_Rect - Design Report Page 1 of 11

Local Buckling. Local Buckling in Columns. Buckling is not to be viewed only as failure of the entire member

twenty steel construction: columns & tension members ARCHITECTURAL STRUCTURES: FORM, BEHAVIOR, AND DESIGN DR. ANNE NICHOLS FALL 2013 lecture

Steel connections. Connection name : MEP_BCF_W=14.29[mm]_W=6.35[mm]_tp=63.5[mm]_N=0_N=2_N=0_N=1_W=14.29[mm]_W=14.29[mm]_W=14.29[ mm] Connection ID : 1

NYIT Instructors: Alfred Sanabria and Rodrigo Suarez

COLUMNS: BUCKLING (DIFFERENT ENDS)

THROUGH PLATE-TO-ROUND HSS CONNECTIONS

Failure in Flexure. Introduction to Steel Design, Tensile Steel Members Modes of Failure & Effective Areas

FHWA Bridge Design Guidance No. 1 Revision Date: July 21, Load Rating Evaluation of Gusset Plates in Truss Bridges

SECTION 7 DESIGN OF COMPRESSION MEMBERS

APRIL Conquering the FE & PE exams Formulas, Examples & Applications. Topics covered in this month s column:

PLATE GIRDERS II. Load. Web plate Welds A Longitudinal elevation. Fig. 1 A typical Plate Girder

SHEAR CONNECTION: DESIGN OF W-SHAPE BEAM TO RECTANGULAR/SQUARE HSS COLUMN SHEAR PLATE CONNECTION

DES140: Designing for Lateral-Torsional Stability in Wood Members

APPENDIX 1 MODEL CALCULATION OF VARIOUS CODES

Design of Reinforced Concrete Beam for Shear

Torsional Analysis of

A Simply supported beam with a concentrated load at mid-span: Loading Stages

the Steel Construction Manual

WRAP-AROUND GUSSET PLATES

3. Stability of built-up members in compression

Direct Strength Method (DSM) Design Guide

Hilti North America Installation Technical Manual Technical Data MI System Version

Hilti North America Installation Technical Manual Technical Data MI System Version

Project data Project name Project number Author Description Date 26/04/2017 Design code AISC dome anchor. Material.

The Influence of a Weld-Affected Zone on the Compressive and Flexural Strength of Aluminum Members

Appendix. A 1 Properties of areas.* *Symbols used are: A = area I = moment of inertia S = Section modulus

Abstract Block shear is a mode of failure in which a steel member fails in tension along one plane and shear on a

It s a bird it s a plane it s Super Table! F y = 50 ksi F u = 65 ksi ASD LRFD ASD LRFD

CHAPTER 2 LITERATURE REVIEW

Unbraced Column Verification Example. AISC Design Examples AISC 13 th Edition. ASDIP Steel is available for purchase online at

research report Design Example for Analytical Modeling of a Curtainwall and Considering the Effects of Bridging (All-Steel Design Approach)

Design of Reinforced Concrete Beam for Shear

Singly Symmetric Combination Section Crane Girder Design Aids. Patrick C. Johnson


CHAPTER II EXPERIMENTAL INVESTIGATION

Example 4: Design of a Rigid Column Bracket (Bolted)

TRANSVERSE PLATE-TO-SQUARE/RECTANGULAR HSS CONNECTIONS

TORSION INCLUDING WARPING OF OPEN SECTIONS (I, C, Z, T AND L SHAPES)

Chapter 9: Column Analysis and Design

Steel Design. Notation:

Appendix K Design Examples

PERFORATED METAL DECK DESIGN

Comparison of AISI Specification Methods for Members with Single Intermediate Longitudinal Stiffeners

Improved Flexural Design Provisions for I-Shaped Members and Channels

host structure (S.F.D.)

Equivalent Uniform Moment Factor for Lateral Torsional Buckling of Steel Beams

5 Compression Members

Appendix J. Example of Proposed Changes

Steel Design. Notation: a A A b A e

Structural Steelwork Eurocodes Development of A Trans-national Approach

S E C T I O N 1 2 P R O D U C T S E L E C T I O N G U I D E - H E L I C A L S C R E W P I L E F O U N D A T I O N S

Tension zone applications, i.e., cable trays and strut, pipe supports, fire sprinklers Seismic and wind loading

Towards The. Design of Super Columns. Prof. AbdulQader Najmi

Lecture Example. Steel Deck (info from Vulcraft Steel Roof and Floor Deck Manual)

Design of Beams (Unit - 8)

RESEARCH REPORT RP02-2 MARCH 2002 REVISION Committee on Specifications for the Design of Cold-Formed Steel Structural Members

Design of Shear Tab Connections for Gravity and Seismic Loads

Advanced Analysis of Steel Structures

AISC LRFD Beam Design in the RAM Structural System

Job No. Sheet 1 of 6 Rev B. Made by IR Date Oct Checked by FH/NB Date Oct Revised by MEB Date April 2006

Beam Design and Deflections

APPENDIX A Thickness of Base Metal

Minimum-weight design of built-up wideflange

This Technical Note describes how the program checks column capacity or designs reinforced concrete columns when the ACI code is selected.

Design of Steel Structures Prof. S.R.Satish Kumar and Prof. A.R.Santha Kumar. Local buckling is an extremely important facet of cold formed steel

Chapter 8: Bending and Shear Stresses in Beams

twenty steel construction: columns & tension members ARCHITECTURAL STRUCTURES: FORM, BEHAVIOR, AND DESIGN DR. ANNE NICHOLS FALL 2018 lecture

Lecture-04 Design of RC Members for Shear and Torsion

Review of Energy Dissipation of Compression Members in Concentrically Braced Frames

Design of a Balanced-Cantilever Bridge

The plastic moment capacity of a composite cross-section is calculated in the program on the following basis (BS 4.4.2):

Interaction Diagram Dumbbell Concrete Shear Wall Unsymmetrical Boundary Elements

Elastic Buckling Behavior of Beams ELASTIC BUCKLING OF BEAMS

Fundamentals of Structural Design Part of Steel Structures

Design of Reinforced Concrete Structures (II)

CIV 207 Winter For practice

County: Any Design: BRG Date: 9/2007 Hwy: Any Ck Dsn: BRG Date: 9/2007. For prestr. beams, assume 12" top flange, therefore take 4" from CL Gird.

Design of a Multi-Storied RC Building

Biaxial Analysis of General Shaped Base Plates

MODULE F: SIMPLE CONNECTIONS

PROFILE SIZES: CONNECTION FORCES BEAM : UB254X146X43 CONNECTION DETAIL: D b = mm W b = mm T b = mm t wb = 7.30 mm r b = 7.

Steel Cross Sections. Structural Steel Design

SHEAR CONNECTION: W BEAM WITH SHEAR PLATE ONE-WAY SHEAR CONNECTION TO W COLUMN WEB

51st Annual Transmission & Substation Design & Operation Symposium DEVELOPMENT OF ANALYTICAL METHODS FOR SPLICED LEG MEMBERS

Direct Strength Method for Steel Deck

Mechanics of Materials Primer

Behavior and Design of Angle Column

Transcription:

Assignment 10 Problem 5.46 LRFD First, select the lightest weight W14 column. Use the recommended design value for K for the pinned-fixed support condition specified (ref. Commentary, Appendix 7, AISC Table C-A-7.1, p. 16.1-511). Compute the column effective length KL using the recommended design value for K. Compute the LRFD factored load. P u = 1.2 D + 1.6 L Using AISC Table 4-1, select the lightest W14 section that has a value of φ c P n for the computed effective length KL that is no less than the value computed for P u. You will need to interpolate between the rows to determine the value of φ c P n. Next, design the column base plate. From Table 1-1 of the AISC Manual, list the pertinent section properties for the selected column section (d, b f ). Determine the base plate area using the following equation (φ c = 0.65). A 1 = P u /[φ c 0.85 f c (A 2 /A 1 ) 1/2 ] (A 2 /A 1 ) 1/2 = 1.0 since A 2 is said to be approximately the same size as the column base plate Check the minimum required area (A 1 ) min for the base plate. - A 1 may not be less than the depth of the column times its flange width (i.e. d x b f ). If (A 1 ) min = d b f > required A 1 (calculated above), use (A 1 ) min as the area of the base plate. Otherwise, use A 1 as the area of the base plate. Compute the base plate dimensions B and N. - Since this is a square base pate B = N. B = N = (A 1 ) 1/2 (Round up to the nearest inch.) Check the bearing strength φ c P p of the concrete using the following equation. φ c P p = φ c 0.85 f c A 1 (A 2 /A 1 ) 1/2 φ c = 0.65 f c = the specified concrete compression strength A 1 = B x N (based on the rounded dimensions determined above). (A 2 /A 1 ) 1/2 = 1.0 Compare the bearing strength of the concrete with the factored column load P u. You should find that φ c P p > P u. Compute the required base plate thickness using the following equation. t min = l (2 P u /0.9 F y B N) 1/2 (Round up to the nearest quarter of an inch.) l = max (m. n, or λn ) (i.e. l is the largest of the values of m, n, or n ) m = (N 0.95 d)/2 n = (B - 0.80 b f )/2 Page 1 of 6

n = ¼ (d b f ) 1/2 λ = 1 B = N = rounded dimensions of the base plate determined previously F y = the minimum specified yield strength of the A36 steel used in the base plate (cf. AISC Table 2-4) Specify the final base plate dimensions. Use the following format: PL B x N x t (A36) ASD First, select the lightest weight W14 column. Use the recommended design value for K for the pinned-fixed support condition specified (ref. Commentary, Appendix 7, AISC Table C-A-7.1, p. 16.1-511). Compute the column effective length KL using the recommended design value for K. Compute the ASD critical load combination. P a = D + L Using AISC Table 4-1, select the lightest W14 section that has a value of P n /Ω c for the computed effective length KL that is no less than the value computed for P a. You will need to interpolate between the rows to determine the value of P n /Ω c. Next, design the column base plate. From Table 1-1 of the AISC Manual, list the pertinent section properties for the selected column section (d, b f ). Determine the base plate area using the following equation (Ω c = 2.31). A 1 = Ω c P a /[0.85 f c (A 2 /A 1 ) 1/2 ] (A 2 /A 1 ) 1/2 = 1.0 since A 2 is said to be approximately the same size as the column base plate Check the minimum required area (A 1 ) min for the base plate. - A 1 may not be less than the depth of the column times its flange width (i.e. d x b f ). If (A 1 ) min = d b f > required A 1 (calculated above), use (A 1 ) min as the area of the base plate. Otherwise, use A 1 as the area of the base plate. Compute the base plate dimensions B and N. - Since this is a square base pate B = N. B = N = (A 1 ) 1/2 (Round up to the nearest inch.) Check the bearing strength P p /Ω c of the concrete using the following equation. P p /Ω c = (1/Ω c ) [0.85 f c A 1 (A 2 /A 1 ) 1/2 ] Ω c =2.31 f c = the specified concrete compression strength A 1 = B x N (based on the rounded dimensions determined above). (A 2 /A 1 ) 1/2 = 1.0 Compare the bearing strength of the concrete with the critical column load combination P a. You should find that P p /Ω c > P a. Page 2 of 6

Compute the required base plate thickness using the following equation. t min = l (3.33 P a /F y B N) 1/2 (Round up to the nearest quarter of an inch.) l = max (m. n, or λn ) (i.e. l is the largest of the values of m, n, or n ) m = (N 0.95 d)/2 n = (B - 0.80 b f )/2 n = ¼ (d b f ) 1/2 λ = 1 B = N = rounded dimensions of the base plate determined previously F y = the minimum specified yield strength of the A36 steel used in the base plate (cf. AISC Table 2-4) Specify the final base plate dimensions. Use the following format: PL B x N x t (A36) Problem 5.50 LRFD Compute the LRFD factored load. P u = 1.2 D + 1.6 L Using AISC Table 4-11, select the lightest angle that has a value of φ c P n for the given effective length KL that is no less than the value computed for P u. This angle will be checked to determine if it has adequate load bearing capacity to satisfy the provisions of Specification Section E5. From Table 1-7 of the AISC Manual, list the pertinent section properties for the selected angle section (A and r x ). Check the ratio b/t to determine if Section E4 or E5 must be used. If b/t > 20, Section E4 is to be used, otherwise Section E5 will be used. b = the length of the angle leg t = the angle thickness You should find the b/t ratio less than 20, and Section E5 must be used. Compute the actual slenderness ratio KL x /r x and compare with the limiting value of 80. Then compute the value of the effective slenderness ratio KL/r that will be used to compute F e from Equation E3-4. If KL x /r x 80, then use Equation E5-1 to determine the effective slenderness ratio KL/r. If KL x /r x > 80, then use Equation E5-2 to determine the effective slenderness ratio KL/r. Compute F e using Equation E3-4. Determine whether Equation E3-2 or E3-3 is the appropriate equation to use in determining F cr by comparing effective slenderness ratio KL/r with the limiting value 4.71(E/F y ) 1/2. If KL/r 4.71(E/F y ) 1/2, then use Equation E3-2 to compute F cr. If KL/r > 4.71(E/F y ) 1/2, then use Equation E3-3 to compute F cr. Page 3 of 6

Compute the nominal strength P n of the single angle column by using the following equation. P n = F cr A g A g = the area for the single angle taken from AISC Table 1-7 Compute the LRFD design strength φ c P n and compare with the LRFD factored load P u. If φ c P n P u, then the selected single angle column section is adequate. If φ c P n < P u, then the selected single angle column section is not adequate. A larger angle section should be selected and checked following the procedure outlined above. Specify the final selection. ASD Compute the ASD critical load combination. P a = D + L Using AISC Table 4-11, select the lightest angle that has a value of P n /Ω c for the given effective length KL that is no less than the value computed for P a. This angle will be checked to determine if it has adequate load bearing capacity to satisfy the provisions of Specification Section E5. From Table 1-7 of the AISC Manual, list the pertinent section properties for the selected angle section (A and r x ). Check the ratio b/t to determine if Section E4 or E5 must be used. If b/t > 20, Section E4 is to be used, otherwise Section E5 will be used. b = the length of the angle leg t = the angle thickness You should find the b/t ratio less than 20, and Section E5 must be used. Compute the actual slenderness ratio KL x /r x and compare with the limiting value of 80. Then compute the value of the effective slenderness ratio KL/r that will be used to compute F e from Equation E3-4. If KL x /r x 80, then use Equation E5-1 to determine the effective slenderness ratio KL/r. If KL x /r x > 80, then use Equation E5-2 to determine the effective slenderness ratio KL/r. Compute F e using Equation E3-4. Determine whether Equation E3-2 or E3-3 is the appropriate equation to use in determining F cr by comparing effective slenderness ratio KL/r with the limiting value 4.71(E/F y ) 1/2. If KL/r 4.71(E/F y ) 1/2, then use Equation E3-2 to compute F cr. If KL/r > 4.71(E/F y ) 1/2, then use Equation E3-3 to compute F cr. Compute the nominal strength of the single angle column by using the following equation. P n = F cr A g Page 4 of 6

A g = the area for the single angle taken from AISC Table 1-7 Compute the ASD allowable strength P n /Ω c and compare with the ASD critical load combination P a. If P n /Ω c P a, then the selected single angle column section is adequate. If P n /Ω c < P a, then the selected single angle column section is not adequate. A larger angle section should be selected and checked following the procedure outlined above. Specify the final selection. Problem 5.54 From Table 1-8 of the AISC Manual, list the pertinent section properties for the given WT6 x 22.5 column member (i.e. A, t f, b f /2t f, d/t w, I x, r x, y, I y, r y, and J). Check for slender elements using AISC Table B4.1a. For the flange, use Case 1. Compare b f /2t f with the limiting value of 0.56(E/F y ) 1/2. - You should find that the flange is not slender. For the stem, use Case 4. Compare d/t w with the limiting value of 0.75(E/F y ) 1/2. - You should find that the stem is not slender. Determine the nominal strength of the column for flexural buckling using Specification Section E3. Determine the controlling slenderness ratio: compute KL x /r x and KL y /r y. K = 1.0 KL x = KL y = the given effective length r x, r y = values taken from AISC Table 1-8 You should find that KL x /r x is the larger value and controls. Since KL x /r x is the controlling slenderness ratio, compute F e (more specifically F ex ) using Equation E3-4. E = 29,000 ksi KL/r = KL x /r x (as previously determined) Determine whether Equation E3-2 or E3-3 is the appropriate equation to use in determining F cr by comparing KL x /r x with the limiting value 4.71(E/F y ) 1/2. - If KL x /r x 4.71(E/F y ) 1/2, then use Equation E3-2 to compute F cr. - If KL x /r x > 4.71(E/F y ) 1/2, then use Equation E3-3 to compute F cr. Next, determine the nominal strength of the column for flexural-torsional buckling using Specification Section E4. Ultimately, Equation E4-2 will be used to compute F cr once values for F cry, F crz, and H are determined. Compute F ey using Equation E4-8. - Use the value for KL y /r y that was previously determined. Page 5 of 6

- The value F ey will be used as the value for F e in either Equation E3-2 or E3-3, whichever equation is determined appropriate. Determine whether Equation E3-2 or E3-3 is the appropriate equation to use in determining F cr (more specifically F cry ) by comparing KL y /r y with the limiting value 4.71(E/F y ) 1/2. - If KL y /r y 4.71(E/F y ) 1/2, then use Equation E3-2 to compute F cr (more specifically F cry ). - If KL y /r y > 4.71(E/F y ) 1/2, then use Equation E3-3 to compute F cr (more specifically F cry ). Determine F crz. - Compute r o 2 : r o 2 = x o 2 + y o 2 + (I x + I y )/A g Equation E4-11 x o = 0 (The shear center of the tee is located at the intersection of the stem and the flange.) y o = y - t f /2 (Values for y and t f are taken from AISC Table 1-8.) I x, I y = values taken from AISC Table 1-8 A g = area of the WT6 x 22.5 (AISC Table 1-8) - Compute H using Equation E4-10. - Compute F crz using Equation E4-3. G = 11,200 ksi (Specification Section E4, listed after Equation E4-9) J, A g = values taken from AISC Table 1-8 Compute F cr using Equation E4-2. Compare the two values of F cr computed for flexural buckling and flexural-torsional buckling. The nominal strength of the column P n is based on the smaller of the two values determined for F cr for flexural buckling and flexural-torsional buckling. Compute the nominal strength of the column using the following equation. P n = F cr A g F cr = the smaller of the two values previously determined A g = the area for the WT6 x 22.5 taken from AISC Table 1-8 Compute the LRFD design strength (φ c P n ) and the ASD allowable strength (P n /Ω c ), φ c = 0.90 and Ω c = 1.67. Note: These values should compare favorably with the values in AISC Table 4-7. Page 6 of 6

2024 © sciencedocbox.com Privacy Policy | Terms of Service | Feedback