STRUCTURES DESIGN MANUAL for Highways and Railways 2013 Edition This electronic file is for reference only. When the content of this electronic file is inconsistent with the hard copy of the Structures Design Manual for Highways and Railways (SDM), 2013 Edition and the Amendments issued, the hard copy of the SDM, 2013 Edition and the Amendments shall prevail. (This Version is Continuously Updated to include Amendments issued) This Electronic File has incorporated the following Amendments:- Rev Issue Date Amendment Incorporated First Issue May 2013 - 1 June 2018 Amendment No. 1/2018 2 April 2020 Amendment No. 1/2020 3 May 2021 Amendment No. 1/2021 Highways Department The Government of the Hong Kong Special Administrative Region © The Government of the Hong Kong Special Administrative Region First published, August 1993. Second edition, November 1997. Third edition, August 2006. 2013 Edition, May 2013 Prepared by : Bridges and Structures Division, Highways Department, Room 1502, Skyline Tower, 39 Wang Kwong Road, Kowloon Bay, Kowloon, Hong Kong. 2 FOREWORD The Structures Design Manual for Highways and Railways provides guidance and sets standards for the design of highway and railway structures in Hong Kong. It has been widely used by practitioners as a reference for local highway and railway structural works since its first publication in August 1993, with second and third editions released in November 1997 and August 2006. In this 2013 edition, the Manual has been revised for migration from British structural design standards to Eurocodes. Minor amendments taking into account experience gained and feedbacks received on the previous editions are also included. Eurocodes are the suites of European Standards covering structural design of civil engineering structures, including highway structures. In March 2010, British structural design standards, including BS 5400 which the previous editions of this Manual drew heavily on for requirements, were withdrawn. In anticipation of this, studies were carried out on the adoption of Eurocodes and the associated UK National Annexes for the design of highway structures in Hong Kong. Design approaches, requirements and parameters in Eurocodes considered not suitable for application in Hong Kong have been modified to suit local conditions, material properties and specifications for civil engineering works, and incorporated into this Manual. This Manual is a guidance document and its recommendations should not be considered as exhaustive. Situation may arise for which considerations and requirements are not fully covered by this Manual. We welcome any comments on this Manual for further improvements. The Bridges and Structures Division of the Highways Department will regularly review and improve on the content of this Manual so that all design standards and guidance will be in line with the most up-to-date practice. ( P. K. LEE ) Chief Highway Engineer / Bridges & Structures Highways Department 3 4 AMD. 1/2020 CONTENTS Page No. TITLE PAGE 1 FOREWORD 3 CONTENTS 5 CHAPTER 1 GENERAL 20 1.1 SCOPE 20 1.2 REFERENCE 21 1.3 DEFINITION 21 1.3.1 Highway Structure 21 1.3.2 Walkway Cover 21 1.3.3 Railway Bridge 21 1.3.4 Culvert 22 1.3.5 Earth-retaining Structure 22 1.3.6 Project Office 22 1.3.7 Designer 22 1.3.8 Checking Engineer 22 1.4 RAILWAY BRIDGES 22 1.5 APPROVED SUPPLIERS OF MATERIALS AND SPECIALIST CONTRACTORS FOR PUBLIC WORKS 23 CHAPTER 2 RELIABILITY MANAGEMENT 24 2.1 RELIABILITY CLASSIFICATION 24 2.2 DESIGN WORKING LIFE 25 2.3 THE USE OF BS EN 1990 ANNEXES 25 2.4 DESIGN CHECKING 25 2.4.1 General 25 AMD. 2.4.2 Classification of Highway Structures 26 1/2020 2.4.3 Checking Engineer 27 2.4.4 Comment by the Chief Highway Engineer/Bridges and Structures 27 AMD. 2.4.5 Checking Process 28 1/2020 2.4.6 Highway Structures Design and Check Certificate 29 Replacement Sheet 1 of 12 5 (AMD. 1/2020) AMD. 1/2018 CHAPTER 3 ACTIONS 33 3.1 GENERAL 33 3.2 COMBINATIONS OF ACTIONS 33 3.2.1 General 33 3.2.2 Crack Width Verification Combination 38 3.2.3 Tensile Stress Verification Combinations for Prestressed Concrete Members 38 3.3 DEAD LOAD AND SUPERIMPOSED DEAD LOAD 39 3.4 WIND ACTIONS 40 3.4.1 General 40 3.4.2 Simplified Procedure for Determining Peak Velocity Pressure 41 3.4.3 Full Procedure for Determining Peak Velocity Pressure 42 3.4.4 Dynamic Response Procedure 46 3.4.5 Wind Forces 47 3.4.6 Force Coefficients and Pressure Coefficients 47 AMD. 3.4.7 Reference Area 53A 1/2018 3.4.8 ULS Partial Factors 53B 3.4.9 ψ Factors 53B 3.5 TEMPERATURE EFFECTS 54 3.5.1 General 54 3.5.2 Uniform Temperature Components 54 3.5.3 Temperature Difference Components 56 3.5.4 Simultaneity of Uniform and Temperature Difference Components 60 3.5.5 Coefficient of Thermal Expansion 60 3.5.6 ULS Partial Factors 60 3.5.7 ψ Factors 60 3.6 ACCIDENTAL ACTIONS 60 3.6.1 General 60 3.6.2 Accidental Actions Caused by Road Vehicles 61 3.6.3 Accidental Actions Caused by Derailed Rail Traffic under or adjacent to Structures 66 3.6.4 Accidental Actions Caused by Ship Traffic 67 3.7 TRAFFIC ACTIONS 67 3.7.1 General 67 3.7.2 Actions on Road Bridges 67 3.7.3 Actions on Footways, Cycle Tracks and Footbridges 72 3.7.4 ULS Partial Factors 73 3.7.5 ψ Factors 73 3.8 SEISMIC ACTIONS 73 Replacement Sheet 1 of 27 6 (AMD. 1/2018) CHAPTER 4 DESIGN FOR EARTHQUAKE RESISTANCE 74 4.1 GENERAL 74 4.2 REFERENCE RETURN PERIOD 74 4.3 REFERENCE PEAK GROUND ACCELERATION 74 4.4 IMPORTANCE CLASS 74 4.5 SEISMIC ACTIONS AS AN ACCIDENTAL ACTION 75 4.6 SIMPLIFIED DESIGN CRITERIA FOR LOW SEISMICITY 75 4.7 SITE DEPENDENT ELASTIC RESPONSE SPECTRUM 75 4.8 SPATIAL VARIABILITY OF SEISMIC ACTIONS 76 4.9 QUASI-PERMANENT VALUES OF MASS CORRESPONDING TO TRAFFIC ACTIONS 76 4.10 STRENGTH VERIFICATIONS – MATERIALS 76 CHAPTER 5 DESIGN OF CONCRETE BRIDGES 77 5.1 GENERAL 77 5.2 MATERIAL PROPERTIES OF CONCRETE 77 5.2.1 Strength 77 5.2.2 Elastic Deformation 80 5.2.3 Linear Coefficient of Thermal Expansion of Concrete 80 5.2.4 Creep 80 5.2.5 Shrinkage 80 5.2.6 Stress-Strain Relations 80 5.3 REINFORCING STEEL 82 5.4 DURABILITY 83 5.4.1 Cement Content 83 5.4.2 Concrete Cover to Reinforcement 83 5.5 CRACK CONTROL 85 5.5.1 General 85 5.5.2 Early Thermal Movement 85 5.6 PRESTRESSING 89 5.6.1 General 89 5.6.2 Post-tensioning Systems 89 5.6.3 External Prestressing 90 7 AMD. 1/2021 AMD. 5.6.4 Specialist Prestressing Contractors 90C 1/2021 5.7 ADDITIONAL MODIFICATIONS TO BS EN 1992 AND THE UK NA TO BS EN 1992 91 CHAPTER 6 DESIGN OF STEEL BRIDGES 94 6.1 GENERAL 94 6.2 FATIGUE 94 6.3 HOT FORMED STRUCTURAL HOLLOW SECTIONS 94 6.4 FABRICATION 95 6.5 BLAST CLEANING 95 6.6 TESTING OF WELDS 95 6.7 HOT DIP GALVANIZING 96 6.8 ADDITIONAL MODIFICATIONS TO BS EN 1993 AND THE UK NA TO BS EN 1993 96 CHAPTER 7 DESIGN OF COMPOSITE BRIDGES 100 7.1 GENERAL 100 7.2 ADDITIONAL MODIFICATIONS TO BS EN 1994 AND THE UK NA TO BS EN 1994 100 CHAPTER 8 BEARINGS 102 8.1 GENERAL 102 8.2 CLASSIFICATION OF BEARINGS 102 8.3 SCHEDULE OF BEARINGS 102 8.4 SUPPLY AND INSTALLATION OF BEARINGS 105 8.5 TESTING 105 8.6 COMPRESSIVE STIFFNESS OF ELASTOMERIC LAMINATED BEARINGS 105 8.7 DESIGN OF FIXINGS FOR BRIDGE BEARINGS 106 8.8 OPERATIONAL REQUIREMENTS 106 CHAPTER 9 MOVEMENT JOINTS 107 9.1 GENERAL 107 8 Replacement Sheet 1 of 4 (AMD. 1/2021) 9.1.1 Movements 107 9.1.2 Selection of Joint Type 107 9.2 PROPRIETARY MOVEMENT JOINTS 109 9.3 TRAFFIC LOADING ON MOVEMENT JOINTS 109 9.4 LOADING OF STRUCTURE BY STRAINING OF MOVEMENT JOINTS 110 9.5 WATERTIGHTNESS OF MOVEMENT JOINTS 110 9.6 FUNCTIONAL REQUIREMENTS OF PROPRIETARY MOVEMENT JOINTS 111 9.6.1 Requirements 111 9.6.2 Specification 111 9.7 SUPPLY AND INSTALLATION OF MOVEMENT JOINTS 112 9.8 DETAILING FOR PROPER INSTALLATION OF MOVEMENT JOINTS 112 9.9 OPERATIONAL REQUIREMENTS 114 CHAPTER 10 FOUNDATIONS AND SUBSTRUCTURES 115 10.1 FOUNDATIONS 115 10.1.1 General 115 10.1.2 Specialist Piling Contractors 115 10.1.3 Piling Downdrag 116 10.1.4 Differential Settlement 116 10.1.5 Cover to Pile Caps and Footings 116 10.2 BRIDGE SUBSTRUCTURES ADJACENT TO RAIL TRAFFIC 116 10.3 RAILWAY UNDERBRIDGE SUBSTRUCTURES 117 10.4 HYDRAULIC EFFECTS ON BRIDGE SUBSTRUCTURES 117 10.4.1 Effects to be Considered 117 10.4.2 Backwater Effects 117 10.4.3 Effects of Waterborne Traffic 118 10.5 RUN-ON-SLABS 118 CHAPTER 11 PARAPETS 119 11.1 GENERAL 119 11.2 VEHICLE PARAPET GROUPS 119 11.2.1 Containment Levels 119 11.2.2 Selection Guidance 120 9 11.3 PARAPET HEIGHTS 120 11.4 DESIGN DETAILS 120 11.4.1 Materials 120 11.4.2 Projections and Depressions 120 11.4.3 Structures Not Exclusively Used as Vehicular Bridges 120 11.5 METAL PARAPETS AND TOP RAILS 121 11.5.1 Design Requirements 121 11.5.2 Corrosion 121 11.5.3 Plinth 122 11.5.4 Bedding 123 11.6 REINFORCED CONCRETE PARAPETS 123 11.6.1 Design Requirements 123 11.6.2 Longitudinal Effects 123 11.7 PEDESTRIAN PARAPETS 124 11.8 BICYCLE PARAPETS 124 11.9 VEHICLE PARAPETS 125 11.10 SIGHT DISTANCES 125 11.11 RAILWAY OVERBRIDGE PARAPETS 125 11.11.1 High Containment Parapets 125 11.11.2 Overbridge Parapets 125 CHAPTER 12 FOOTBRIDGES AND SUBWAYS 139 12.1 GENERAL 139 12.2 COVERS 139 12.3 STAIRWAYS 140 12.4 RAMPS 140 12.5 LANDINGS 141 12.6 CHANGES IN DIRECTION 141 12.7 DIMENSIONS 141 12.8 PARAPETS AND HANDRAILS 142 12.9 DRAINAGE 142 10 12.10 LIGHTING 144 12.11 ESCALATORS 144 12.11.1 Provision of Escalators 144 12.11.2 General Requirements 145 12.11.3 External Applications 145 12.11.4 Inspection and Surveillance 146 12.12 FINISHES 146 12.13 WATERPROOFING 147 12.13.1 General Requirements 147 12.13.2 Covers for Footbridges, Covered Walkways and Pedestrian Subways 147 12.13.3 Pedestrian and Bicycle