MEP Seismic & Wind Provisions of ASCE Prepared for the 2017 Rochester Engineering Symposium Richard Sherren, P.E.

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1 MEP Seismic & Wind Provisions of ASCE 7-10 Prepared for the 2017 Rochester Engineering Symposium Richard Sherren, P.E. 1

2 New York State Model Building Code The state of New York has adopted the 2015 International Building Code as its model building code. The seismic provisions for nonstructural components (MEP components) are found in ASCE 7-10 Chapter 13. The wind provisions for roof top equipment are found in ASCE 7-10 Chapter 29. 2

3 Seismic Provisions 3

4 Change of Nomenclature Occupancy Category becomes Risk Category. Occupancy Category I Risk Category I Occupancy Category II Risk Category II Occupancy Category III Risk Category III Occupancy Category IV Risk Category IV 4

5 Seismic Design Category ASCE 7-10 Section The Seismic Design Category is determined by the Structural Engineer of Record. It is found on the 1 st sheet of the structural drawings where the basis of design is specified. This Seismic Design Category applies to all of the nonstructural components in the building. 5

6 Component Importance Factor ASCE 7-10 Section q The Component Importance Factor,, will have a value of either 1.0 or 1.5. It is different from the Structural Importance Factor,. q The Component Importance Factor is assigned by the Engineer of Record for the system or equipment under consideration. 6

7 if: 1. The component is a life safety component, that is required to function following an earthquake. 2. The component contains, supports, or moves substances that are highly toxic or explosive. 3. The component is in or attached to a Risk Category IV building, and is needed for the continued operation of that facility, or the failure of the component could impair the continued operation of the building. 4. The component contains, supports or moves highly toxic or explosive material and is in or attached to a building that has been classified as a hazardous occupancy. 7

8 General Exemptions ASCE 7-10 Section Nonstructural Components in Seismic Design Category A are exempt. (ASCE 7-10 Section 11.7) 2. Mechanical & Electrical Components in Seismic Design Category B are exempt. 3. Mechanical & Electrical Components in Seismic Design Category C are exempt if their =

9 General Exemptions ASCE 7-10 Section Mechanical & Electrical Components in Seismic Design Categories D, E, or F where the following apply; a. = 1.0. b. The component is positively attached to the structure. c. Flexible connections are provided between the component and attached duct, piping, or conduit, and either; i. The component weight is 400 lbs or less and its C.G. is 4 ft. or less above the floor; or ii. The component weighs 20 lbs or less, or for distributed systems, 5 lbs/ft or less. 9

10 Designated Seismic Systems ASCE 7-10 Section Active mechanical & electrical systems that must remain operable after an earthquake must be certified by the manufacturer through shake table testing or experience data unless the component can be demonstrated to be inherently rugged. 2. Components containing hazardous materials that have = 1.5 must be certified as maintaining containment following an earthquake by analysis, shake table test, or experience data. 10

11 Consequential Damage ASCE 7-10 Section The failure of an essential or nonessential architectural, mechanical, or electrical component shall not cause the failure of an essential component. 11

12 Component Anchorage ASCE 7-10 Section Component attachments are to be bolted welded, or otherwise positively attached to the building structure w/o counting on frictional forces due to gravity. 2. A continuous load path of sufficient strength and stiffness is required between the component and the building structure. 12

13 Design Force in Attachment ASCE 7-10 Section = h For Concrete Anchorage

14 Component Anchorage ASCE 7-10 Sections ü Anchors in concrete are to be designed per ACI 318 Appendix D. New requirements lead to larger and/or more anchors. üanchors in masonry are to be designed per TMS 402/ACI 530/ASCE 5. üpost installed anchors in concrete are to be prequalified for seismic applications per ACI

15 Power Actuated Fasteners ASCE 7-10 Section v Power actuated fasteners in concrete or steel are not to be used for sustained loads or seismic braces in Seismic Design Categories D, E, or F unless approved for seismic applications. vpower actuated fasteners cannot be used in masonry unless approved for seismic loading. 15

16 Friction Clips ASCE 7-10 Section Friction clips are not to be used for resisting sustained loads as well as resisting seismic loads. C-type beam clamps and large flange clamps are permitted for hangers if they are equipped with restraining straps equal to those found in NFPA 13 Section

17 Electrical Components ASCE 7-10 Section Electrical Components with = 1.5 require seismic restraint. I believe that this is referring to electrical equipment, transformers, and control boxes. Most electrical equipment in Risk Category IV buildings will fall under the essential category and be assigned = 1.5. Due to the dangerous nature of high voltage equipment, I would suspect that most would be given =

18 Electrical Distribution Systems ASCE 7-10 Section Seismic Restraints are not required where either; a. Trapeze supported raceways where the total weight of the raceway supported by the trapeze assemblies weighs less than 10 lbs/ft. b. The raceway is supported by hangers and each hanger is 12 in. in length or less from the raceway support point to the structure. Where rod hangers are used, they must be equipped with swivels to prevent inelastic bending of the rod. 2. Seismic restraints are not required for conduit less than 2.5 inches in trade size regardless of the value of. 18

19 Ductwork ASCE 7-10 Section Seismic Restraints are not required for ductwork where either; a. Trapeze supported ductwork where the total weight of the raceway supported by the trapeze assemblies weighs less than 10 lbs/ft. b. The ductwork is supported by hangers and each hanger is 12 in. in length or less from the duct support point to the structure. Where rod hangers are used, they must be equipped with swivels to prevent inelastic bending of the rod. 2. The duct is less that 6 ft 2 in diameter, or weigh less than 17 lbs/ft. 19

20 Ductwork ASCE 7-10 Section The preceding exemptions do not apply to ductwork that is designed to carry toxic, highly toxic or flammable gases. They also do not apply to duct work used for smoke control. 20

21 Ductwork ASCE 7-10 Section Ductwork fabricated and installed in accordance with standards that have been approved by the authority having jurisdiction are deemed to meet the requirements of ASCE 7-10 Chapter

22 Ductwork ASCE 7-10 Section Components that are in-line with the duct and weigh 75 lbs. or less do not require independent support or seismic bracing. They should be positively attached to the duct with mechanical fasteners. 22

23 Piping Systems ASCE 7-10 Section Seismic restraints are not required where one of the following applies. 1. Trapeze supported pipe where no pipe exceeds the size limits for the various seismic design categories and component importance factors and the total weight of the pipe is less than 10 lb/ft. 2. The piping is supported by hangers that are 12 in. or less in length from the top of the pipe for clevis hung pipe, and from the top of the trapeze assembly for trapeze supported pipe to the supporting structure. Where hanger rods are used they are to be equipped with swivels to prevent inelastic bending of the rod. 23

24 Piping Systems ASCE 7-10 Section For piping with an 4.5 seismic restraints are not required for; a. Seismic Design Category C, = 1.5, and the nominal pipe size is 2 in. or less. b. Seismic Design Category D, E, or F, = 1.5, and the nominal pipe size is 1 in. or less. c. Seismic Design Category D, E, or F, = 1.0, and the nominal pipe size is 3 in. or less. With the introduction of 4.5 in the code language, and the addition of a plumbing category to Table , there are no longer any size exemptions for Drain, Waste, and vent lines. 24

25 ASME Pressure Piping ASCE 7-10 Section Pressure piping systems and their supports that have been designed and constructed in accordance with ASME B31 are deemed to meet the requirements of ASCE 7-10 Chapter

26 Fire Protection Sprinkler Systems ASCE 7-10 Section Fire protection sprinkler systems that have been supported and braced per NFPA 13 are deemed to meet the requirements of ASCE 7-10 Chapter

27 Seismic Restraint Devices 27

28 Snubbers (Bumpers) Single Axis Snubber Two Axis Snubber Three Axis Snubber 28

29 Post Type Seismic Isolator Free Standing Isolator Restraint Housing Three Axis Snubber 29

30 Plate Type Seismic Isolator Adjustment Spacers Isolator Top Plate Four Three Axis snubbers Restraint Housing Free Standing Isolator 30

31 Single Restraint Plate Type Seismic Free Standing Isolator Isolator Isolator Top Plate Restraint Housing Three Axis Snubber 31

32 Clip for Solid, Non-Isolated Equipment Attachment Seismic Anchor Qualified Per ACI Bracket Sized for a Specific Capacity 32

33 Cable Restraints for Pipe & Duct Cable angles are to be 30 to 60. These are a bit to Steep to be Totally Effective. Cable Restraints Two Cables Required per Location 33

34 Damage to Nonstructural Component During NZ Earthquake 34

35 Duct Saved by Cable Restraints During NZ Earthquake 35

36 Wind Provisions 36

37 Wind Loads 2015 IBC Sections & Buildings, structures, and parts thereof shall be designed to withstand the minimum wind loads prescribed herein. Decreases in wind loads shall not be made for the effect of shielding by other structures. Wind Loads on every building or structure shall be determined in accordance with Chapters 26 to 30 of ASCE 7 37

38 Wind Loads ASCE 7-10 Chapter 29 Section 29.5 This chapter defines roof top structures and equipment to be part of the Main Wind Force Resisting System (MWFRS) of the building. Details the horizontal wind load and the vertical uplift wind load acting on the equipment. Note that there are no exemptions in the wind provisions of the code or ASCE 7. 38

39 Uplift Loads on Equipment ASCE 7-10 Section 29.5 Consideration of uplift loads due wind acting on roof top equipment is now part of the code. This will require more restraint capacity than in the past. In ASCE 7-05 consideration of uplift forces was only recommended in the commentary. 39

40 New Basic Wind Speeds ASCE 7-10 Figures A, B, & C Risk Category II Figure 25.1A: 115 mph for Upstate New York. Risk Categories III & IV Figure B: 120 mph for Upstate New York Risk Category I Figure C : 105 mph for Upstate New York. The wind importance factor,, is incorporated in the basic wind speeds. 40

41 ASCE 7-10 Wind Pressures Although wind speeds have increased, the load combinations Tend to lower the overall wind forces acting on the equipment. 41

42 Exposure Category & Wind Speed Exposure Category and Basic Wind Speed are defined in the Basis of Design usually found on the first sheet of the structural drawings. 42

43 All Pieces of Roof Top Equipment Require Restraint Horizontally and Vertically 43

44 Need for Wind Restraint 44

45 Unrestrained Solar Panels 45

46 One Approach to Wind Restraint 46

47 Attach Equipment to its Curb Screws Attaching Equipment to Curb Roof Curb 47

48 Isolators for Wind Restraint The same isolators used for seismic restraint may also be used for wind restraint. 48

49 Choose the Proper Isolators 49

50 Isolators for Condensing Units Frame Must be Engineered to Transfer Wind Loads to Isolators Post Type Isolators with Three Axis Restraints 50

51 Isolators for Cooling Towers Dunnage Must be Engineered to Transfer Wind Loads to Isolators Plate Type Isolators with Three Axis Restraints 51

52 Roof Curb for HVAC Units Isolators with Three Axis Restraints HVAC Unit Must be Securely Attached to the Isolated Rail using an Engineered design to Resist the Wind Loads Securely Attach to Structure 52

53 Effect of Wind Speed on Isolation Efficiency 53

54 Questions 54

55 Thank You for Your Attention 55