TECHNICAL DIGEST 3

STRUCTURAL DESIGNOF STEEL JOISTROOFS TO RESISTPONDING LOADS

20

The information presented in this publication has been developed by James M. Fisher, Ph.D, P.E.,Dist.M.ASCE, Consulting Engineer for the Steel Joist Institute and Mark D. Denavit, Ph.D., P.E. Assistant Professor, Department of Civil and Environmental Engineering, University of Tennessee, Knoxville in conjunction with the SJI’s Engineering Practice Committee and the SJI’s Research Committee, and is produced in accordance with recognized engineering principles and is for general information only. The SJI and its committees have made a concerted effort to present accurate, reliable, and useful information on the structural design of steel joist roofs to resist ponding loads. The information contained in this digest should not be used or relied upon for any specific project without competent professional assessment of its accuracy, suitability and applicability by a licensed professional engineer or architect. The publication of the material contained in this Technical Digest is not intended as a representation or warranty on the part of the Steel Joist Institute. Any person making use of this information does so at one’s own risk and assumes all liability arising from such use.  Federal Regulations Governing Erection of Joist Products Steel joists and Joist Girders must be erected in accordance with the Occupational Safety and Health Administration (OSHA), U.S. Department of Labor 29 CFR Part 1926 Safety Standards for Steel Erection. The erection of Open Web Steel Joists is governed by Section 1926.757 of this Federal Regulation.

Copyright © 2018

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Steel Joist Institute All rights reserved. This Technical Digest or any part thereof must not be reproduced in any form without the written permission of the Steel Joist Institute.

Printed in the United States of America

Third Edition First Printing – February 2018

TECHNICAL DIGEST 3

STRUCTURAL DESIGN OF STEEL JOIST ROOFS TO RESIST PONDING LOADS

allowable strength requiredstrength

safety factor

Design strength allowable strength

joist Joist Girder

joist Joist Girder

joist

load LRFDASD

Resistance factor nominal strength

joist JoistGirder

Limit state structural componentloads

design strengthrequired strength

resistance factor safety factorStandard Specifications

structural analysis LRFDASD StandardSpecifications

nominal strength loadload

nominal strength loadload

Joist Girder

yield stress

loads

chordsjoist Joist Girder

yield point yield strength

International Plumbing Code

International Plumbing Code.”

a b b b

b b b

a b b b

b b b

b b b

b b b

a

b

Source

The commentary to Section B3.10 states

(Defined in Roof Bay Analysis Spreadsheet)

(Values include1.15 factor forshear deformations)

Joist Girder size can be revised by inputting larger loads in the ''optional increased load data'' section of the Roof Bay Analysis spreadsheet

(Defined in Roof Bay Analysis Spreadsheet)

undeformed

(Values include1.15 factor forshear deformations)

(Values include1.15 factor forshear deformations)

Joist size can be revised by inputting larger loads in the ''optional increased load data'' section of the Roof Bay Analysis spreadsheet

o

=

(Defined in Roof Bay Analysis Spreadsheet)

undeformed

(Values include1.15 factor forshear deformations)

(Values include1.15 factor forshear deformations)

Joist Girder size can be revised by inputting larger loads in the ''optional increased load data'' section of the Roof Bay Analysis spreadsheet

o

(Defined in Roof Bay Analysis Spreadsheet)

deformed

(Values include1.15 factor forshear deformations)

Joist Girder size can be revised by inputting larger loads in the ''optional increased load data'' section of the Roof Bay Analysis spreadsheet

(Defined in Roof Bay Analysis Spreadsheet)

(Values include1.15 factor forshear deformations)

(Defined in Roof Bay Analysis Spreadsheet)

undeformed

(Values include1.15 factor forshear deformations)

Joist size can be revised by inputting larger loads in the ''optional increased load data'' section of the Roof Bay Analysis spreadsheet

Joist Girder size can be revised by inputting larger loads in the ''optional increased load data'' section of the Roof Bay Analysis spreadsheet

(Values include1.15 factor forshear deformations)

Joist size can be revised by inputting larger loads in the ''optional increased load data'' section of the Roof Bay Analysis spreadsheet

Joist Girder size can be revised by inputting larger loads in the ''optional increased load data'' section of the Roof Bay Analysis spreadsheet

Specification for Structural Steel Buildings,

Minimum Design Loads and Associated Criteria for Buildings and Other Structures

2015 International Building Code

2015 International Plumbing Code

Additional references relevant to ponding, but not cited within this Digest include: