Snow loads : guide to the snow load provisions of ASCE 7-16

Michael O'Rourke provides an detailed and authoritative interpretation of the snow load provisions of Standard ASCE/SEI 7-16, accompanied by 35 practical design examples. Contents......Page 6 Preface......Page 10 Unit Conversions......Page 12 Chapter 1: Introduction......Page 14 Chapter 2: Ground Snow Loads......Page 18 2.1 The Map: Influence of Latitude, Elevation, and Coastlines......Page 21 2.3 State Tables......Page 22 Example 2-1. Ground Snow Loads......Page 24 3.1 Measured Conversion Factors......Page 26 3.2 Flat Roof Snow Load......Page 30 3.3 Exposure Factor......Page 31 3.4 Thermal Factor......Page 32 3.5 Importance Factor......Page 33 3.6 Minimum Snow Loads for Low-Sloped Roofs......Page 34 Example 3-1. Roof Exposure......Page 35 4.1 Snow Sliding......Page 38 4.2 Air-Supported Structures......Page 44 4.3 Overall Comparison with Observations......Page 45 Example 4-1. Uniform Roof Snow Load, Monoslope Roof (1 on 12)......Page 46 Example 4-2. Uniform Roof Snow Load, Monoslope Roof (4 on 12)......Page 47 Example 4-3. Uniform Roof Snow Load, Wide Gable Roof......Page 48 5.1 Continuous-Beam Systems......Page 50 5.2 Other Structural Systems......Page 53 Example 5-1. Uniform and Partial Snow Loads, Monoslope Roof with Overhang......Page 54 Example 5-2. Partial Snow Load, Continuous Purlins in Gable Roof (1 on 12)......Page 57 Example 5-3. Partial Snow Load, Continuous Purlins in Gable Roof (3 on 12)......Page 58 Example 5-4. Partial Snow Load, Cantilevered Roof Girder System......Page 59 6.1 Hip and Gable Roofs......Page 62 6.2 Curved Roofs......Page 66 6.3 Sawtooth-Type Roofs......Page 67 Example 6-2. Unbalanced Snow Load, Wide Gable Roof......Page 68 Example 6-3. Unbalanced Snow Load, Asymmetric Gable Roof......Page 69 Example 6-4. Balanced and Unbalanced Snow Loads, Curved Roof......Page 71 Example 6-5. Unbalanced Snow Load, Sawtooth Roof......Page 73 Chapter 7: Drifts on Lower Roofs......Page 76 7.1 Leeward Drift......Page 78 7.2 Windward Drift......Page 83 7.4 Roof Steps in Series......Page 85 Example 7-1. Roof Step Drift Load......Page 86 Example 7-2. Roof Step Drift, Limited Height......Page 88 Example 7-3. Roof Step Drift, Low Ground Snow Load......Page 89 Example 7-4. Roof Step Drift, Adjacent Structure......Page 91 Example 7-5. Roof Steps in Series......Page 92 Chapter 8: Roof Projections......Page 94 Example 8-1. Parapet Wall Drift......Page 97 Example 8-2. Rooftop Unit Drift......Page 100 Example 8-3. Parapet Wall Drift, Low Ground Snow Load......Page 101 Example 8-4. Elimination of RTU Drift......Page 103 9.1 Adjacent Roofs......Page 104 9.2 Separated Roofs......Page 106 Example 9-1. Sliding Snow Load, Residential Gable Roof (4 on 12)......Page 107 Example 9-2. Sliding Snow Load, Commercial Gable Roof (1 on 12)......Page 108 Example 9-3. Sliding Load, Separated Roof......Page 110 Chapter 10: Rain-on-Snow Surcharge Loads......Page 112 Example 10-2. Uniform Design Snow Load, Gable Roof (1/4 on 12)......Page 116 11.1 Ponding Instability......Page 118 11.2 Existing Roofs......Page 120 Example 11-2. Susceptible Bays Purlin-Perpendicular Geometry......Page 121 12.1 Floor-Level Snow Loads......Page 122 Example 12-1. Isolated Cable Tray......Page 123 Example 12-2. Adjacent Cable Trays......Page 124 Design Example 1......Page 126 Design Example 2......Page 132 Design Example 3......Page 138 Chapter 14: Frequently Asked Questions......Page 144 References......Page 170 Index......Page 172 About the Author......Page 176 The devastating tsunamis that struck Chile and Japan in 2010 and 2011 underscored the critical need for new structural design criteria to improve building resilience and safeguard human life. They also provided a wealth of information that could form the basis for estimating tsunami loads and effects and guiding the development of a design methodology. A team of researchers and practitioners took up the challenge, which resulted in the inclusion of provisions for tsunami loads in Standard ASCE/SEI 7-16, Minimum Design Loads and Associated Criteria for Buildings and Other Structures.For many US structural and geotechnical engineers, ASCE 7-16's provisions and commentary will be their first exposure to tsunami design. In this companion guide, author Ian Robertson helps engineers and allied professionals understand the background and development of the new provisions. He guides them through the application of tsunami design with a series of clear and detailed examples based on prototypical buildings. He connects the ASCE 7-16 tsunami provisions to prior design guidelines, laboratory research, and field surveys. In addition, he explains the key concepts in the provisions, including tsunami risk categories; inundation depth and flow velocities; structural design procedures; and hydrostatic, hydrodynamic, and debris impact loads. Robertson demonstrates the application of these concepts in numerous examples and a full-length tsunami design of a prototype building. The guide also explains the tsunami provisions for foundation design, structural countermeasures, vertical evacuation refuges, nonstructural components and systems, and critical nonbuilding structures.Tsunami Loads and Effects: Guide to the Tsunami Design Provisions of ASCE 7-16 is a clear and authoritative explanation of the tsunami load requirements that will be welcomed by structural, coastal, and geotechnical engineers, as well as architects, building code officials, contractors, and emergency managers. Prototype buildings General requirements Tsunami risk categories Analysis of design inundation depth and flow velocity Inundation depths and flow velocities based on runup Inundation depths and flow velocities based on site-specific probabilistic tsunami hazard analysis Structural design procedures for tsunami effects Hydrostatic loads Hydrodynamic loads Debris impact loads Foundation design Structural countermeasures for tsunami loading Tsunami vertical evacuation refuge structures Designated nonstructural components and systems Non-building tsunami risk category III and IV structures Frequently asked questions References. Provides a detailed, authoritative description of the snow load provisions of Standard ASCE/SEI 7-16. With clear, concise language, Michael O'Rourke explains the theory and research that underpin the provisions and shows how to apply them to the design of new and existing structures that could collect falling or drifting snow.