ASCE 17-96-1997 Air-Supported Structures《空气支撑结构》.pdf

1、ASCE 17-96 American Society of Civil Engineers Air-Supported Structures ASCE ASCE 17-96 American Society of Civil Engineers Air-Supported Structures Published by 5c1e American society 5 of Civil Engineers 345 East 47th Street New York, NY 10017-2398 Abstract: This Standard provides minimum criteria

2、for the design and operation of air-supported membrane structures whether independent of or attached to another structure. Specifically, it discusses such topics as: 1) Materials and their properties; 2) building systems such as fire protection; 3) design criteria; 4) erection and inflation; and 5)

3、operation and maintenance. Library of Congress Cataloging-in-Publication Data American Society of Civil Engineers. Air-supported structures I American Society of Civil Engineers. p. cm. “ASCE 17-96.“ ISBN 0-7844-0116-0 1. Air-supported structures-Standards. I. Title. TH1099.A425 1997 97-13560 624-dc

4、21 CIP Photocopies. Authorization to photocopy material for internal or personal use under circumstances not falling within the fair use provisions of the Copyright Act is granted by ASCE to libraries and other users registered with the Copyright Clearance Center (CCC) Transactional Reporting Servic

5、e, provided that the base fee of $4.00 per article plus $.50 per page is paid directly to CCC, 222 Rosewood, Drive, Danvers, MA 01923. The identification for ASCE Books is 0-7844-0116-0/97/$4.00 + $.50 per page. Requests for special permission or bulk copying should be addressed to Permissions . Thi

6、s pressure is to be deter mined under the required design load combinations. Air-supported structure: structure consisting of a membrane that achieves and maintains its shape and support by air pressure within the occupied space. Approved: approved by the authority having jurisdiction. Authority hav

7、ing jurisdiction: the organization, political subdivision, office, or individual charged with the responsibility of administering and enforc ing the provisions of this Standard. Deflation index: a calculated value used to ensure a margin of safety for emergency egress. Design strength: the product o

8、f the nominal strength and a resistance factor. Fabrics Coated fabric: a base fabric to which is bonded a supplementary coating. The base fabric carries the membrane stresses. Laminated fabric: a flexible material composed AIR-SUPPORTED STRUCTURES of superimposed layers firmly united by bonding or i

9、mpregnating with an adherent polymeric material to one or more surfaces. One or more of these layers is a textile fabric. Factored load: the product of the nominal load and a load factor. Fan: an air-moving device, including axial, centrifugal, or propeller fans or blowers. Films: unreinforced flexi

10、ble sheets made of a single layer or laminated multiple layers of PVC, polyethylene, or other materials. Inflation system: all necessary components of a mechanical system required for inflation and opera tion of an air-supported structure; this may include, but is not limited to, fans, motors, back-

11、draft dampers, relief dampers, heaters (where required), housings, ducts not fully contained in the pressur ized space, standby power, and controls. Life-cycle factor: a factor which recognizes that the strength of a material decreases with time because of the effects of continuous loading, environm

12、ental exposure, and aging. Limit state: condition in which a structure or component becomes unfit for service and is judged either to be no longer useful for its intended function (saviceability limit state) or to be unsafe (strength limit state). Load effects: forces and deformations produced in st

13、ructural members and components by the loads. Load factor: a factor that accounts for unavoid able deviations of the actual load from the nominal value, its statistical variation, and uncertainties in the analysis that transform the load into a load effect. Loads: forces or other actions that affect

14、 structural systems such as the weight of all materials, occu pants, and their possessions; internal pressure; environmental effects; differential settlement; and restrained dimensional changes. Membrane: the pliable structural fabric or film of the air-supported structure. Membrane liner: an interi

15、or fabric or film used for decorative, acoustical, thermal insulation, or other nonstructural purpose. Nominal loads: the loads as specified in ASCE 7. Nominal strength: the capacity of a structure or component to resist the effects of loads, as deter mined by computations using specified material s

16、trengths and dimensions and formulas derived from accepted principles of structural mechanics or by field tests or laboratory tests of scaled models, AIR-SUPPORTED STRUCI1JRES allowing for modeling effects and differences between laboratory and field conditions. Resistance factor: a factor that acco

17、unts for unavoidable deviations of the actual strength from the nominal value and the manner and consequences of failure. Strength design: a method of proportioning struc tural members using load factors and resistance factors such that no applicable limit state is entered (also called load and resi

18、stance factor design). Storm: a disturbance of the normal conditions of the atmosphere. It is divided into four categories: Hail storm: a storm that results in a fall of transparent ice pellets, or of hard pellets consisting of a mixture of snow and ice. Rain storm: any rain that deposits 0.5 in. (1

19、3 mm) or more of water in any 1 hour period or that deposits 0. 75 in. (19 mm) or more of water in any consecutive 24 hour period. Snow storm: a storm that deposits 6 in. (152 mm) or more of snow in any consecutive 24 hour period. Wind storm: a storm in which winds of 45 MPH (72 km/h) or more are ex

20、perienced as defined in ASCE7. 1.3 References The following Standards are referred to in this document. ASCE 7-93 American Society of Civil Engineers, Minimum Design Loads for Buildings and Other Structures. ASHRAE 51-1985 Laboratory Methods for Testing Fans for Rating. ASTM D 4851-88 Standard Test

21、Methods for Coated and Laminated Fabrics for Architectural Use. ASTM E 84-91a Standard Test Method for Surface-Burning Characteristics of Building Materials. ASTM E 108-90 Standard Test Method for Determining the Fire Retardancy of Roof Covering Materials. ASTM E 136-82 Standard Test Method for Beha

22、vior of Materials in a Vertical Tube Furnace at 750C. NFPA 37-1990 Installation and Use of Stationary Combustion Engines and Gas Turbines. NFPA 701-1989 Standard Methods of Fire Tests for Flame-Resistant Textiles and Films. NFPA 780-1992 Lightning Protection Code. 2 2.0 Materials 2.1 General Materia

23、ls used in air-supported structures shall confonn to the requirements of Section 2 and shall be tested by qualified testing agencies acceptable to the authority having jurisdiction. 2.2 Membrane 2.2.1 General. Membranes for air-supported structures shall be fabrics or films. When the mem brane is re

24、inforced, the reinforcing shall comply with Section 2.3. Membrane materials shall be of uniform quality, have the properties required for the intended usage, and shall be free of defects that impair the structural integrity or cause leakage of water, deterioration, or other damage. 2.2.2 Physical pr

25、operties. Membrane physical properties shall be determined in accordance with ASTM D 4851. A record of compliance shall be maintained by the fabricator. 2.2.3 Fire performance. 2.2.3.J Membranes. Membranes for air-sup ported structures shall be classified according to their fire performance characte

26、ristics as follows. (a) Class IA: Noncombustible membranes shall meet the requirements of NFPA 701 and ASTM E 136. In addition, they shall attain a flame spread index no greater than 25 and a smoke development index no greater than 50 according to ASTM E 84, and a class A rating according to ASTME 1

27、08. (b) Class IB: Noncombustible membranes shall satisfy the requirements for Class IA mem branes except that a class B rating according to ASTM E 108 shall be attained. (c) Class IIA: Limited combustible mem branes shall meet the requirements of NFPA 701. In addition they shall attain a flame sprea

28、d index no greater than 25 and a smoke development index no greater than 450 according to ASTM E 84 and a Class C rating according to ASTM E 108. (d) Class IIB: Limited combustible mem branes shall meet the requirements ofNFPA 701 and shall attain a flame spread index no greater than 25 and a smoke

29、development index no greater than 450 according to ASTM E 84. (e) Class III: Combustible membranes are all membranes that do not meet the requirements for any other class. 2.2.3.2 Membrane liners. Membrane liners shall be classified as in Section 2.2.3.1 but need not meet the requirements of ASTM E

30、108. 2.2.4 Fuel and occupancy loads. Membranes and membrane liners shall be used for air-supported structures according to the classification given in Sections 2.2.3.1 and 2.2.3.2, respectively, and shall conform to the Building Code or the fuel and occu pancy limits given in Appendix A, if Appendix

31、 A is accepted by the authority having jurisdiction. 2.3 Cables and Reinforcing 2.3.1 General. When reinforcing of the mem brane or membrane liner is required, it shall consist of either metallic or nonmetallic cables, or non metallic reinforcing. 2.3.2 Metallic cables. Strength and fire charac teri

32、stics of such cables shall be determined in accordance with material standards approved by the authority having jurisdiction. 2.3.3 Nonmetallic cables and webs. The strength characteristics of such cables and webs shall meet the requirements of Section 4 when such characteristics are determined in a

33、ccordance with material standards approved by the authority having jurisdiction. The fire performance characteristics shall be equivalent to those of the membrane to which the cables or webs are attached if loss of a single cable or web element will initiate progressive collapse. 2.3.4 Nonmetallic r

34、einforcing. The strength and fire performance characteristics of fabric reinforce ments of the membrane at stress points shall be in accordance with Sections 2.2.2 and 2.2.3. 2.4 Membrane Seams 2.4.1 Fabrication methods. Membranes shall be joined together by welding, sewing, cementing, or any other

35、method approved by the authority having jurisdiction. 2.4.2 Seam strength. Membrane joints shall be fabricated so that the seams meet the following strength criteria. (a) At 68F (20C) the joint shall resist a continuous load equal to 200% of the maximum unfactored load for a minimum of 4 hours; and

36、(b) At 158F (70C) the joint shall resist a con tinuous load equal to 100% of the maximum unfactored load for a minimum of 4 hours. 2.5 Mechanical Joints When a mechanical joint in the membrane or membrane liner is required, the materials used shall AIR-SUPPORTED STRUCTURES be noncorrosive or shall b

37、e treated and/or finished to protect against corrosion. Mechanical joints shall meet the strength criteria of Sections 2.4.2(a) and 2.4.2(b). 3.0 Building Systems 3.1 Notation The following notations apply Ae = Equivalent leakage area of building as designed with doors closed, ft2 (m2) D; = Deflatio

38、n index (dimensionless) LA = Total air loss accounting for exiting, scfm (sm3/s) LE = Loss due to exiting at Pv. scfm (sm3/s) LM = Supply air at Pv, scfm (sm3/s) LN = Normal operating loss at Pv, scfm (sm3/s) N0 = Posted number of occupants Pv = Residual pressure during exiting with doors open, in.

39、H20 (Pa) V1 = Volume of air above 7.0 ft (2.1 m), ft3 (M3) 3.2 General Ancillary systems and components used in the construction of air-supported structures shall con form to the requirements of this section. Their eval uation shall be carried out by qualified testing agen cies approved by the autho

40、rity having jurisdiction. 3.3 Mechanical Systems 3.3.1 Inflation air supply equipment 3.3.1.1 Inflation systems. Air-supported struc tures shall be provided with a sufficient quantity of air-supply devices, including but not limited to fans, drivers, and controllers, so that in the event of fail ure

41、 of one such device, the inflation system shall have sufficient reserve capacity to maintain the performance requirements of Section 3.3.1.2. The system controls shall be interlocked so that transfer to alternate air-Slpply devices and standby power required by Section 3.7.3 will occur automatically

42、. 3.3.J.2 Air supply capacity. Each inflation system shall have performance characteristics that will provide the design range of operating pressures in accordance with Section 4.2.3. In addition, each system shall be capable of meeting the requirements 3 AIR-SUPPORTED STRUCTURES for indoor air qual

43、ity (Section 3.3.2) and smoke management (Section 3.4.3). Required perfonnance shall take into account the normal losses of air pressure in all duct work, filters, heating and/or cooling systems, dampers, louvers, grills, vents, walls, roof membrane connection to anchorage systems, roof membrane con

44、nection to openings, and those due to the penneability of the membrane. The maximum total pressure developed by each inflation system shall not exceed the design maxi mum internal pressure. 3.3. I .3 Deflation. The inflation system capac ity of structures that could deflate below a height of 7 .0 ft

45、 (2.1 m) shall be designed to maintain a deflation index Di, of not less than 1.0. The deflation index shall be determined as follows. Di = 0.05 V1 ; in S.I. 0.0008 V1 LA LA where LA is the total air loss accounting for exiting, given by where LN = 2610Ae(Pv)05; in S.I. 0.839Ae(Pv)05 LE = 115N0(Pv)0

46、5; in S.I. 0.0563(Pv)0.5 3.3.1.4 Fan requirements. Fans in both the primary inflation and emergency inflation systems shall meet the following requirements. (a) Fan performance shall be determined in accordance with ASHRAE 51; (b) Fan selection shall be based on stable operation throughout the entir

47、e range of required operating conditions; (c) Fan drivers shall be rated for continuous duty; (d) Fan inlets, outlets, and drive elements shall be protected in accordance with OSHA Regulations; (e) Fans and their associated drivers shall be suitable for the environment to which they are exposed; and

48、 (f) Fans shall be equipped with back draft dampers or spring-loaded motor driven dampers that fail to the closed position (to prevent air pressure loss) when the fans are not in operation. 3.3.I.5 Ducting. Duct work shall be support ed and protected from weather, seismic, and impact damage. The air

49、 intake to fan units shall be located so as to ensure protection against blockage due to accumulating or blowing snow, ice, flooding, or 4 debris and to avoid the intake of toxic fumes, nox ious fumes, and smoke. 3.3.2 Indoor air quality. The ventilation system shall be designed to prevent harmful concentrations of known contaminants within the building. 3.3.3 Snow removal. Snow melting systems shall be designed in accordance with 4.2.4.2. 3.4 Fire Protection Fire protection shall meet the following require ments and shall conform to the building code or the requirements