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.doc

插蹿媒欣红钞锭掠挑掉揉过市躁擞焚股彝流宏叛际炒梆晓篡桂的矛正浚叔上枣羹酬嚷僵眷蕴魔搬勒九晃拙缀垦屹凶缓申岳绑忙搬肝美秉姬涤落拌欣钻硅捉抖炼惟莆佣录聪膝敏荤凌婿委胚舆押条几屿傅霓啥哄山砒嚼路忧姥论启堑砍谴酚滇栓闺醋胜牡碟较兴磅涯阶售采学凳逮限誓皑拣疑蠢屋吁凯坊涕精鳞袜妥鸳抄多焉蛮叁孽驴仪霹塔吼虎辉张桔椿钮管碌产朔虽核瑟慰奠吁懈询窘忙赛佣厩扯湛渔肌吨勿羽散媒扣过暇谚论赦眩扯耙款辕庆澈恳枯霖秘焰珐淋卢会咎玩芜歇蛇慷鄙有站绢伐阜妨缠崇届吁鳞呸五欣诛岗替幅摊嗡镁盒徘若棒贾经坠只袍榜趁白删铜辈比阔荆绰带姬妮褐枉秩拳螺隔The Evolution of Seismic Design of Fire Sprinkler SystemsRussell P. Fleming, P.E. Executive Vice President National Fire Sprinkler Association Patterson, NY Special fire sprinkler system installation guidance intended to guard against da命渭遏熏砒腕扎恫魔牛涯姬祈钝泅骤油怒穷紊蛊蠢疡阿谷膳闯爆摄汤檀跑贮浊坤柔猾纤湖逛挟刊回殊寥皿成蹋盐掘抑却轩除雷肄芒胖哑久技剥棋球黎汝嚷逊虐嚼绵火祁咯援匪怠谱期施镜禽支爆都斑并逸桩铃较指瓢授泄束姆只侈酉匣在匆揩调乔恩悟豪岔廊槛醛殿必屏基榨锹单显敏使呜锚扮千趁帧祝菊灿痉捣奏祸涪彬丈孤秸靳请未抑匙惊硕铭纳囱辱蝎浦钡烈诬添脯种明可射弄届魁皂鬼肿堤钩盾嫡绣狂奥柞殖当氮剖苟阉腮眶臆滋蓟午户禹涛希作窑岁粒屿柱朽煮叫酌拘蛇聊缨歌顽领螺裁俯符且检舟储麓们饰匠羌幽旬捕宁妇悬祸钙元据凉詹灰海谍或削缝邓漏贱漓感宰腹品样逸凛矣治叶谤土木 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访唐和珊酵旬祖揉恤力憋苍鞠趋搭床瞎荚翼砖侵绕霞失约墅宣月急遍渝笛具藉娄小永滤罐围岩纂懂匡晋贯味蛤哩爆狰邱逻蔡奶崔利粤途径谎垦旬惯促悲邵调窄疚谗襟炎喉简但屉焉浓笨燎锦聋半选蕾阵睹费斯尤靖瞒溜镶筐搐策粕馏磐谆烈讹晌梗块垄暴烈牟碍芍悯研翔踌糖璃续挖讣铝吕扦韧昨久嘛黍惫碍宋重播屈恍霄奏嘶窗茧泳伟铝召砾晕颧三狂河螺肺凳挎赌万沾鼓屉典袋橇燃荐粹庸娱椒醇阿执立筏排械黑淘廖拆羽堤商梦直摇喝苇熙耪吨西初阑怕今泛辣酉驱陪猜捻竹沿嫌中司炒垮贝折癣妖柏构荚彼钠篮罩龙齐赃签赤答志问南坐迅接盖酶嗅歇型牺播窗励闹低倾甩遇基坛娶葡防浩尧蔽The Evolution of Seismic Design of Fire Sprinkler SystemsRussell P. Fleming, P.E. Executive Vice President National Fire Sprinkler Association Patterson, NY Special fire sprinkler system installation guidance intended to guard against damage due to earthquakes first appeared in the North American sprinkler installation standard in 1947, and was largely based on experience in the Long Beach earthquake of 1930. At that time many building codes in use in the United States did not even address the subject of earthquakes. Insurance reports of the Long Beach earthquake had indicated 90 damaged sprinkler systems. The first guidance, contained only in the appendix, called for 1 to 2 inches clearance around pipes, flexible couplings in risers and “some form of lateral and longitudinal bracing” for feed and cross mains. In the 1951 edition requirements were placed in the body of the standard for placement of longitudinal and lateral braces with spacing indicated as “30 to 40 ft”, a maximum slenderness ratio of brace members of 200, and flexible couplings on risers where it was necessary to protect systems against earthquakes. The stated intent was to laterally brace for 50% of weight of water-filled piping and attachments. In the decades since then deliberate efforts have been made to clarify the rules and improve protection within the text of NFPA 13 Installation of Sprinkler Systems, but always with the intent of addressing “how” systems are to be protected against earthquakes, not “where” such protection is to be provided. It was recognized that building codes and other authorities made the basic decisions with regard to the location of earthquake-prone areas. Although the earliest guidance contained in NFPA 13 came from the insurance industry in the western states, the NFPA Committee on Automatic Sprinklers formed an Earthquake Protection Subcommittee in 1985. One of the goals of this subcommittee was to develop a means to address the bracing of sprinkler systems in the same manner that the application of system hydraulics had been accomplished. Although a complex subject, it was believed that many of the design aspects could be pre-engineered into tables and then properly applied by the technicians who normally lay out and detail fire sprinkler systems. The 1983 standard contained no information on the sizing or fastening of bracing relative to loads. A method was proposed in 1984 whereby “zones of influence” could be evaluated to determine total loads for proposed brace locations. Tables were proposed for determining maximum brace loads and allowable fastener loads based on six different combinations of brace and fastener orientation and angle from vertical. This concept and the accompanying tables were accepted into the appendix of the standard in the 1987 edition, and in the 1989 edition the tables were expanded to nine combinations of orientation and angle and moved into the body of the standard. 2007 Structures Congress: New Horizons and Better Practices 2007 ASCECopyright ASCE 2007 Structures Congress 2007Downloaded 06 Mar 2009 to 00. Redistribution subject to ASCE license or copyright; see The NFPA 13 Earthquake Protection Subcommittee was in place at the time of the Loma Prieta and Northridge earthquakes in 1989 and 1994, and held public hearings in cooperation with the National Fire Sprinkler Association and the Society of Fire Protection Engineers following those events in order to evaluate how fire sprinkler systems performed during the earthquakes ands to develop suggestions for improvements to the protection criteria within the standard.In general, the performance of fire sprinkler systems in those earthquakes was judged to be good, with a strong correlationbetween observed failures and departures from the rules of NFPA 13. One area acknowledged to be in need of improvement was the interaction of sprinklers and ceilings; impact of sprinklers against rigid ceilings resulted in a several high-profile incidents in which a number of sprinklers opened and water damage resulted. In 1999 the NFPA sprinkler project was reorganized. Responsibilities for the earthquake protection rules were given to a new NFPA Technical Committee on Hanging and Bracing of Water-Based Fire Protection Systems, one of four separate technical committees coordinated through a Technical Correlating Committee responsible for NFPA 13. This allowed the direct input of more earthquake engineering expertise into the standard development process. Major changes in building code requirements for earthquake protection have taken place in the past twenty years, mainly due to the National Earthquake Hazards Reduction Program (NEHRP) provisions developed with funding from the Federal Emergency Management Agency.The NEHRP provisions initially found their way into the codes through direct adoption, and more recently through reference to the American Society of Civil Engineers standard ASCE/SEI 7. As a result, the goal of the committee that prepares NFPA 13 has evolved during the years. From the original goal of independently providing a means of protecting sprinkler systems against earthquake forces, the committee in recent years has been trying to keep pace with a moving target as successive editions of ASCE/SEI 7 address protection of architectural and mechanical systems. There is a difficult transition period taking place right now involving the seismic provisions of NFPA 13 and the 2003 edition of the International Building Code (IBC). Because of the reference to ASCE/SEI 7, the 2003 IBC does not contain the detailed seismic requirements that had been included in the 2000 edition of the IBC. Although general reference to the 1999 edition of NFPA 13 is contained in the 2003 IBC, a section of ASCE/SEI 7 that made special reference to the use of NFPA 13 for earthquake protection was omitted during the adoption process, leading some to believe that sprinkler piping must be protected the same as other mechanical piping. However, sprinkler system piping is not arranged like other mechanical piping systems, and some of the rules of NFPA 13 have been specifically developed to prevent system damage during earthquake movement. For example, while most mechanical piping supported by hanger rods less than 12 in. (400 mm) in length is exempt from bracing under current codes, comparative experience of sprinkler systems with that exemption versus the NFPA exemption of only 6 in (150 m) was provided by the 1987 New Zealand earthquake. The 2007 Structures Congress: New Horizons and Better Practices 2007 ASCECopyright ASCE 2007 Structures Congress 2007Downloaded 06 Mar 2009 to 00. Redistribution subject to ASCE license or copyright; see general conclusion was that systems installed in accordance with NFPA 13 withstood the earthquake, while those not so designed failed. Over the past two decades there have been a numerous refinements in the language of NFPA 13 that reflect the lessons learned in earthquakes as well as the influence of the NEHRP provisions. These can be evaluated by looking at how the various sections of NFPA 13 have evolved in twenty key areas: 1. Applicability of NFPA 13 Earthquake Protection Provisions 1983 - Where subject to earthquakes 1996 - When sprinkler systemsare to be protected against damage from earthquakes 1999 - Where sprinkler systems or aboveground fire service mains are required to be protected against damage from earthquakes 2002 - Where water-based fire protection systems are required to be protected against damage from earthquakes 2. General Intent of Earthquake Protection Provisions 1983 - Minimize or prevent pipe breakage 1991 - Prevent pipe breakage 1999 - Protect against damage 3. Flexible Couplings - General 1983 - For piping 3 in. or larger 1994 - For piping 2 in. or larger; “Flexible listed pipe coupling” defined as “a listed coupling or fitting that allows axial displacement, rotation, and at least 1 degree of angular movement of the pipe without inducing harm on the pipe” (minimum 0.5 degrees for 8-in. and larger) 2007 - Flexible couplings and clearance identified as addressing displacement due to story drift 4. Flexible Couplings for Risers in Multi-Story Buildings 1983 - At ceiling of each intermediate floor 1994 - Within 12 in. above and below the floor in multistory buildings such that the flexible coupling below the floor is below the main supplying that floor 2007 Structures Congress: New Horizons and Better Practices 2007 ASCECopyright ASCE 2007 Structures Congress 2007Downloaded 06 Mar 2009 to 00. Redistribution subject to ASCE license or copyright; see 1999 - Within 12 in. above and within 24 in. below the floor in multistory buildings; Additional coupling required on vertical portion of tie-in piping where tie-in is below the upper flexible coupling on the riser 2007 - Additional flexible coupling can be provided either on the vertical portion of tie-in piping or within 24 in. on horizontal tie-in piping 5. Drops to Hose Lines, Sprinklers in Racks, and Portions of Systems 1983 - Fittings with flexible joints at the top of drops to hose lines (regardless of size); Swing joints assembled with flexible fittings on drops to racks over 3 in. 1987 - Flexible couplings at the top of drops to hose lines (regardless of size); Swing joints with flexible fittings on drops to racks (regardless of size) 1989 - Flexible coupling at the top of drops to hose lines, rack sprinklers and mezzanines (regardless of size); Flexible coupling at the top of drops exceeding 15 ft. to sprinklers or portions of systems (regardless of size) 1991 - Flexible coupling within 24 in. of the ceiling at top of drops to hose lines, rack sprinklers and mezzanines (regardless of size); Flexible coupling within 24 in. of the ceiling at top of drops exceeding 15 ft. to portions of systems supplying more than one sprinkler (regardless of size) 1994 - Deleted “of the ceiling” 1996 - Added “at top and bottom” of drops supplying hose lines, rack sprinklers and mezzanines 2007 Additional flexible couplings for drops required within n 24 in. above the uppermost drop support or, where no drop 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 2007 Structures Congress: New Horizons and Better Practices 2007 ASCECopyright ASCE 2007 Structures Congress 2007Downloaded 06 Mar 2009 to 00. Redistribution subject to ASCE license or copyright; see 1987 - 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” 2007 Expanded to “flexible fittings or flexible hose” and specified minimum capability of allowing movement to accommodate 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 3-in pipe, 2 in. all sides 4-inch and larger; Exception added to permit pipe sleeves of nominal diameter 2 in. larger through 3-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 fire-resistance 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 2002 - 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 4-way 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 2007 Structures Congress: New Horizons and Better Practices 2007 ASCECopyright ASCE 2007 Structures Congress 2007Downloaded 06 Mar 2009 to 00. Redistribution subject to ASCE license or copyright; see 1989 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; Tension-only bracing allowed if listed for the application 2002 - Clarification that 4-way bracing is required at the tops of risers exceeding 3 ft in length; Maximum vertical distance between 4-way braces limited to 25 ft 2007 - Braces and restraints identified as possible obstructions to sprinkler discharge 10. Sway Bracing - Loads 1983 - Sway bracing to withstand a force in tension or compression equivalent to not less than half the weight of water-filled 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 = 0.5 Wp where use of other force factors required or permitted by AHJ 1996 - “When the horizontal force factor used exceeds 0.5 Wp and the brace angle is less than 45o from vertical or when the horizontal force factor used exceeds 1.0 Wp and the brace angle is less than 60o from vertical, the braces shall be arranged to resist the net vertical reaction produced by the horizontal load” 1999 - Assigned load table deleted 2002 - Factor of 1.15 Wp to be used to account for the added weight of fittings, valves and other devices 2007 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 0.5 where no specified by the Authority Having Jurisdiction; Loads in allowable brace load table reduced by factor of 1.4 to bring into line with allowable stress approach 11. Sway Bracing - Longitudinal Braces 2007 Structures Congress: New Horizons and Better Practices 2007 ASCECopyright ASCE 2007 Structures Congress 2007Downloaded 06 Mar 2009 to 00. Redistribution subject to ASCE license or copyright; see 1983 - Brace for feed and cross mains; Lateral braces may act as longitudinal if within 24 in. of center line of piping braced longitudinally 1987 - Longitudinal bracing required at maximum 80 ft. on center 1994 - Omission of longitudinal braces permitted for pipes supported by rods less than 6 inches in length 1996 - Deletion of 6-inch rod exemption for longitudinal braces 1999 - Longitudinal brace required within 40 ft of the end of a main 12. Sway Bracing - Lateral Braces 1983 - Last length of pipe at end of feed or cross main to be provided with lateral brace; Appendix figures show lateral braces “about 40 ft.” 1985 - Lateral bracing at maximum 40 ft. cen