土木建筑外文翻译外文文献英文文献消防自动喷水灭火系统抗震设计

土木建筑外文翻译外文文献英文文献消防自动喷水灭火系统抗震设计内容摘要：

p support is provided, within 24 in. above the bottom of the drop 6. Flexible Couplings for Expansion Joints 1983 On one side of building expansion joints 1987 At or near building expansion joints。 Seismic separation assembly needed for seismic separation joints 1999 – Within 24 in. of building expansion joints 7. Seismic Separation Assemblies 2020 Structures Congress: New Horizons and Better Practices 169。 2020 ASCE Copyright ASCE 2020 Structures Congress 2020 Downloaded 06 Mar 2020 to . Redistribution subject to ASCE license or copyright。 see Swing joints assembled with flexible fittings required where piping crosses seismic joints。 Figure added to appendix 1989 Added “regardless of size” 1991 Designated as “seismic separation assemblies with flexible fittings”。 Added applicability only “above ground level” 2020 – Expanded to “flexible fittings or flexible hose” and specified minimum capability of allowing movement to acmodate closing of the separation, opening of separation to twice normal size, and movement relative to the separation in the other two dimensions in an amount equal to the separation distance 8. Clearances 1983 Clearance through walls, floors, platforms and foundations 1 in. all sides through 3189。 in pipe, 2 in. all sides 4inch and larger。 Exception added to permit pipe sleeves of nominal diameter 2 in. larger through 3189。 in. pipe (4 in. larger for 4 inch and larger pipe)。 Another exception added for pipe passing through gypsum board or equally frangible construction not required to have a fireresistance rating 1985 Flexible joints permitted to substitute for clearance for pipe entering a basement wall with ground water conditions 1987 Flexible couplings or swing joints within one foot of both sides permitted to substitute for clearance in any wall 1994 Flexible coupling within 1 ft. of each side accepted as alternative for walls, platforms and foundations 2020 Clearance dimensions to be considered nominal。 Clearance not required for horizontal piping passing perpendicularly through successive studs or joists that form a wall/ceiling assembly。 Clearance not required for nonmetallic pipe having flexibility equal to flexible couplings within 1 ft. of both sides. 9. Sway Bracing General 1983 Piping to be tied to the structure for minimum relative movement, but allowing for expansion, and differential movement within and between structures。 Tops of risers secured against drifting in any direction using 4way brace 1987 – Zone of influence method added to appendix with maximum load tables for pipe, angles, rods and flats based on three ranges of angle from vertical and maximum slenderness ratio of 200 2020 Structures Congress: New Horizons and Better Practices 169。 2020 ASCE Copyright ASCE 2020 Structures Congress 2020 Downloaded 06 Mar 2020 to . Redistribution subject to ASCE license or copyright。 see – Table for maximum brace loads moved to body of standard 1994 System piping to be supported to resist both lateral and longitudinal horizontal loads 1996 System piping to be supported to resist both lateral and longitudinal horizontal loads and vertical loads。 Each run of pipe between a change in direction to be provided with both lateral and longitudinal bracing。 Exception for runs less than 12 ft. in length supported by braces on adjacent runs。 Tensiononly bracing allowed if listed for the application 2020 Clarification that 4way bracing is required at the tops of risers exceeding 3 ft in length。 Maximum vertical distance between 4way braces limited to 25 ft 2020 Braces and restraints identified as possible obstructions to sprinkler discharge 10. Sway Bracing Loads 1983 Sway bracing to withstand a force in tension or pression equivalent to not less than half the weight of waterfilled piping 1989 Assigned load table added. Alternative permitted for zone of influence method: For lateral braces all branch lines and mains within zone For longitudinal braces all mains within zone 1994 Multipliers permitted for horizontal force factor Fp = Wp where use of other force factors required or permitted by AHJ 1996 “When the horizontal force factor used exceeds Wp and the brace angle is less than 45o from vertical or when the horizontal force factor used exceeds Wp and the brace angle is less than 60o from vertical, the braces shall be arranged to resist the vertical reaction produced by the horizontal load” 1999 Assigned load table deleted 2020 Factor of Wp to be used to account for the added weight of fittings, valves and other devices 2020 – Table included of “Seismic Coefficients” to allow determination of horizontal seismic loads based on mapped values of short period response parameter SS。 Seismic coefficient to be where no specified by the Authority Having Jurisdiction。 Loads in allowable brace load table reduced by factor of to bring into line with allowable stress approa。