醫院消防撒水系統耐震性能補強評估方法研究

Abstract

建築物的耐震性能一直視為耐震研究中十分重要的一環，而建物的耐震性能不斷提升，可有效減低地震對於房屋結構的傷害。然而從過去許多地震經驗中，於醫院中造成人命傷亡或財產損失的往往不是建築物破壞，而是非結構物的損壞。 若發生中小型地震，於醫院某處發生漏水或天花板經撒水頭碰撞發生粉塵掉落、擴孔等災情；抑或發生大地震，醫院撒水系統支撐處失去抗震能力，可能造成醫院中斷正常醫療機能，且無法阻止淹水、火災等二次災害。因此，消防撒水系統需要以性能設計法進行耐震評估，若耐震容量不足則必須進行補強。 為了評估國內醫院建築之消防撒水系統是否具備足夠耐震能力，抑或需補強，本研究修正葉昶辰[29]提出之消防撒水系統耐震詳細評估(方法A)以及適合工程師應用之簡化評估流程(方法C)，並參考NFPA13[5]補強之建議，提出四種補強方案。以案例醫院為例，針對消防管線系統耐震性能表現建立易損性曲線，探討不同地震歷時之結果與適用性，並比較管線系統補強前與補強後之差異。研究內容簡述如下: 1. 非結構性能評估方法架構建議：根據葉昶辰酌修FEMA P58性能設計概念，考量案例醫院結構在沒有發生倒塌，且可修復的前提下，進而探討結構物附屬之非結構系統易損性，即消防管線等設備物之易損性分析。 2. 近遠域地震及規範AC156之管線受震需求分析與影響性探討：本研究輸入之地表歷時依據FEMA P695規定之自然地震歷時，將輸入波分為兩類，一為遠域地震歷時，二為近域地震歷時，其後將地表輸入波輸入至既有案例醫院結構數值模型，其建置於數值軟體MIDAS，而得非線性結構樓板反應。此外，本研究另依據AC156建立與需求反應譜相容之樓板加速度歷時，探討管線易損性分析使用之輸入波特性影響以及地震強度增量規劃。 3. 消防撒水管線系統損壞狀態定義：延續胡佩文[14]與葉昶辰[29]定義管線系統中較常受損之元件，分別為天花板粉塵掉落、螺紋接頭斷管漏水以及吊桿崩落等三性能點，以此為判段損壞依據，並酌修吊桿破壞之判定，建立管線元件易損性曲線。 4. 案例醫院消防管線系統詳細分析(方法A)：利用數值軟體SAP2000V19修正既有醫院受損病房所在樓層之管線模型，建立更多符合實際行為之非線性元件，進行增量非線性動力分析並統計分析結果，以評估消防管線之耐震性能。 5. 案例醫院消防管線系統之補強設計：以既有醫院受損病房所在樓層之管線模型，並分別建立加入四種補強方案之模型，進行增量非線性動力分析並統計分析結果，並比較原始模型與四種補強方案之結果，期望可提供管線最佳補強方案，使管線性能點不超出容許值且符合經濟效益。 6. 案例醫院消防管線系統簡化評估(方法C)：本研究延續葉昶辰[29]提出之簡化評估表(方法C)，其依據方法A中原始模型與補強模型之大量分析結果，求得消防管線動力行為與輸入波反應譜之對應關係，推估放大係數值並應用於方法C。修正適合工程師應用之未補強前初步評估表格，並進一步提出補強後可用之初步評估表格，據以估算消防管線之耐震能力，使工程師可快速得到補強後管線之耐震能力。

Recently, the seismic capacity of critical building structures (such as hospitals and high-tech factories) has improved due to the vigorous development of performance design concepts. As a result, major damage and economic losses caused by earthquakes has changed from predominantly structural to non-structural systems such as piping systems. The common failures to fire protection sprinkler systems resulting from seismic events include impact damage to ceiling boards, leaks to the one-inch threaded joints, and breakage of the hangers. In order to better understand the seismic vulnerability of the components mentioned above, this research revised the detailed numerical analysis method (Method A) developed by Yeh (2016) [29]. Referring to NFPA13[5], this study proposes four strengthened cases of piping system. It take NTU Hospital Yunlin branch as an example to conduct the fragility analysis of the component in fire protection sprinkler system. The research contents are briefly described as follows: 1. Performance design method for piping systems: Referring to FEMA P58[1], an assessment of the sprinkler piping systems will only be meaningful when the buildings structures are judged as reparable. In this study, seismic performance of the sprinkler piping will only be evaluated when the structure is deemed as reparable. 2. The seismic demand analysis and influence discussion of near-fault and far feild earthquakes and specified in AC156: This research selects two methods of obtaining the floor response time history. One is by inputting an original far-field earthquake and a near-fault earthquake into a nonlinear numerical model of the RC structure of the example hospital building. This is established using MIDAS software. The other is referring to AC156[25], employing a Required Response Spectrum (RRS) to determine a compatible floor response time history. 3. Definition of damage status of fire sprinkler pipeline system: Hu (2015) [14] and Yeh (2016)[29] define the most commonly damaged components in pipeline system. the common seismic failures resulted from fire protection sprinkler systems are impact damages of ceiling boards, leakages of 1inch threaded joints and breaks of hangers. In this thesis, revise the criteria of the hanger, and establish the fragility curve of the piping system. 4. Detailed numerical model of the horizontal sprinkler piping system (Method A): It was established more nonlinear components which conform to the actual behavior using ‎SAP2000 software to simulate nonlinear behaviors of hangers and the nonlinear relationship between piping and ceiling systems or partition walls. The fragility parameters of three seismic performance of piping system were than obtained through incremental dynamic analyses. 5. Strengthened cases of fire sprinkler pipeline system : This study proposed four strengthening schemes of piping systems based on the NFPA 13. The effectiveness of seismic strengthening works was determined by comparing the fragility curves of original and strengthened configurations of the sample piping system. The fragility curves were obtained according to detailed analysis results. 6. Simplified assessment method (Method C) : This study proposed a simplified assessment method of original and strengthened systems according to the dynamic characteristics of the sprinkler piping system. It provided engineers with an alternative method that enables rapid and approximate judgment in the seismic performance of sprinkler piping systems based on in situ observations and a generic floor response spectrum, such as AC156[25].