NIST NCSTAR 1-1B Federal Building and Fire Safety Investigation of the World Trade Center Disaster Comparison of Building Code Structural Requirements S. K. Ghosh Xuemei Liang National InstituteofStandardsandTechnology • TechnologyAdministration • U.S. DeportmeniofCommerce NIST NCSTAR 1-1B Federal Building and Fire Safety Investigation of World Trade Center Disaster Comparison of Building Code Structural Requirements S. K. Ghosh Xuemei Liang S. K. GhoshAssociates, Inc. September 2005 U.S. Department of Commerce Carlos M. Gutierrez, Secretary TechnologyAdministration Michelle O'Neill, Acting UnderSecretaryfor Technology National Institute ofStandards and Technology William Jeffrey, Director Disclaimer No. 1 Certain commercial entities, equipment, products, ormaterials are identified in this document in orderto describe a procedure orconcept adequatelyorto trace the history ofthe procedures and practices used. Such identification is not intended to imply recommendation, endorsement, orimplication thatthe entities, products, materials, or equipment are necessarilythe best available forthe purpose. Nordoes such identification imply a finding offaultor negligence bythe National Institute ofStandards and Technology. Disclaimer No. 2 The policy ofNIST is to usethe International System ofUnits (metric units) in all publications. In this document, however, units are presented in metric units orthe inch-pound system, whichever is prevalent in the discipline. Disclaimer No. 3 Pursuantto section 7 ofthe National Construction SafetyTeam Act, the NIST Directorhas determined that certain evidence received by NIST in the course ofthis Investigation is "voluntarily provided safety-related information"that is "not directly related tothe building failure being investigated" and that "disclosure ofthat information would inhibitthe voluntary provision ofthattype ofinformation" (15 USC 7306c). In addition, a substantial portion ofthe evidence collected by NIST in the course ofthe Investigation has been provided to NIST under nondisclosure agreements. Disclaimer No. 4 NISTtakes no position asto whetherthe design orconstruction ofa WTC building was compliantwith any code since, due tothe destruction ofthe WTC buildings, NIST could not verifythe actual (oras-built) construction, the properties and condition ofthe materials used, orchangesto the original construction made overthe life ofthe buildings. In addition, NIST could not verifythe interpretations ofcodes used by applicable authorities in determining compliance when implementing building codes. Where an Investigation report states whethera system was designed or installed as required by a codeprovision. NIST has documentaryor anecdotal evidence indicating whetherthe requirementwas met, or NIST has independentlyconducted tests or analyses indicating whetherthe requirement was met. Use in Legal Proceedings No partofany report resulting from a NIST investigation into a structural failure orfrom an investigation underthe National Construction SafetyTeam Act may be used in any suitoraction for damages arising out ofany matter mentioned in such report (15 USC 281a; as amended by P.L. 107-231). National Institute ofStandards and Technology National Construction SafetyTeam Act Report 1-1B Natl. Inst. Stand. Technol. Natl. Constr. Sfty. Tm. Act Rpt. 1-1B, 280 pages (September2005) CODEN: NSPUE5 U.S. GOVERNMENT PRINTING OFFICE WASHINGTON: 2005 For sale bythe Superintende—nt of Documents, U.S. Gov—ernment Printing Office internet: bookstore.gpo.gov Phone: (202) 512-1800 Fax: (202) 512-2250 Mail: Stop SSOP, Washington, DC 20402-0001 Abstract This reportprovides a comparison ofthe structuralprovisions of: (1) the New York City Building Code, 1968 edition. (2) the New York City Building Code. 2001 edition, (3) the New York State Building Construction Code, 1964 edition, (4) the Municipal Code ofChicago, 1967 edition, and (5) the Building Officials and Code Administrators (known as BOCA) Basic Building Code, 1965 edition. Detailed comparisons are provided in a tabular form. The comparisons are summarized in the body ofthe report. Keywords: Code, construction, design, foundations, loads, materials, standards. WorldTrade Center. NISTNCSTAR 1-1B, WTC Investigation iii Abstract This page intentionally leftblank. iv NISTNCSTAR 1-1B, WTC Investigation Table of Contents Abstract iii List ofFigures ix List ofTables xi List ofAcronyms and Abbreviations xiii Metric Conversion Table xv Preface xix Executive Summary xxix Chapter 1 Introduction 1 Chapter2 Codes included in Comparison 3 Chapter 3 Overview of Codes Compared 5 3.1 1968 and 2001 New York City Building Codes 5 3.2 1964 New York State Building Code 6 3.3 1967 Chicago Municipal Code 6 3.4 1965 BOCA-Basic Building Code 7 Chapter4 Loads 9 4.1 Dead Loads 9 4.2 Floor Live Loads 10 4.3 RoofLive Loads 12 4.4 Moving Loads 12 4.5 Partial Loading Conditions 12 4.6 RoofLive Load Reduction 12 4.7 Floor Live Load Reduction 12 4.8 Wind Loads 16 4.9 Earthquake Loads 20 4.10 Snow Loads 21 4.1 1 Soil and Hydrostatic Pressure 21 NISTNCSTAR 1-1B. WTC Investigation v Table ofContents 4.12 Construction Loads 21 4.13 FluidPressures 22 4.14 Ice Loads 22 4.15 Thermal Forces 22 4.16 Shrinkage 22 4.17 Distribution ofVertical andHorizontal Loads 22 Chapter 5 Structural Work.. 23 5.1 Standards 23 5.2 Aheration ofExisting Buildings 23 5.3 Materials and Methods ofConstruction 24 5.4 Used and UnidentifiedMaterials 25 5.5 Equivalent Systems ofDesign 25 5.6 Stability 25 5.7 Bracing 25 5.8 Secondary Stresses 26 5.9 Load Combinations 26 5.9.1 Allowable Stress Design 26 5.9.2 Ultimate Strength Design 27 5.10 Deflection Limitations 28 5.11 Load Tests/Core Tests 29 5.12 ExteriorWall Materials 29 5.13 Prefabricated Construction 29 5.14 Masonry Construction 29 5.15 Concrete 30 5.16 Steel 31 5.17 Wood ;....33 5.18 Aluminum 35 5.19 Reinforced Gypsum Concrete 35 5.20 Thin Shell andFoldedPlate Construction 36 5.21 Suspended Structures 36 Chapter6 Foundations 37 6.1 GeneralRequirements 37 NISTNCSTAR WTC vi 1-1B, Investigation Table ofContents 6.2 Soil Investigations 37 6.3 Foundation Loads 38 6.4 Allowable Soil Bearing Pressures 38 6.5 Soil LoadBearing Tests 39 6.6 Footings, Foundation Piers, and Foundation Walls 39 — 6.7 Pile Foundations General requirements 40 — 6.8 Pile Foundation Loads 40 6.9 Pile Driving Operations 40 6.10 Pile Types- Specific Requirements 41 6.11 Underpinning 41 6.12 Stability 41 6.13 Inspection 41 Chapter7 Detailed Comparison Tables 43 Chapter 8 Summary 45 Chapters References 47 Annex A1 Reference Standards of 1968 New York City Building Code 173 Annex A2 Reference Standards of 2001 New York City Building Code 185 Annex A3 Reference Standards of 1964 New York State Building Construction Code 193 Annex A4 Reference Standards of 1967 Chicago Municipal Code 197 AnnexA5 Reference Standards of 1965 BOCA Building Code 199 Annex B1 Tables in 1968 New York City Building Code 217 NISTNCSTAR 1-1B, WTC Investigation vii Table ofContents Annex B2 Tables in 2001 New York City Building Code 229 Annex B3 Tables in 1964 New York State Building Construction Code 231 Annex B4 Tables in 1967 Chicago Municipal Code 237 Annex 85 Tables in 1965 BOCA Basic Building Code 239 NISTNCSTAR WTC viii 1-1B, Investigation