第三十五卷第二期 (期別136) (109年)

作者:

第三十五卷第二期(期別136)(109年)

標題混凝土潛變及自體收縮對鋼管混凝土柱之影響研究及設計建議
作者游雅如、陳振川、廖文正
關鍵字鋼管混凝土、潛變、自體收縮、應力轉移、B4-TW潛變收縮模式
摘要鋼管混凝土柱(Concrete-filled steel tubular column，簡稱CFT柱)具高強度、高韌性，被視為具有良好耐震性能的結構構件。早期鋼管內灌混凝土是為了增加構件的側向勁度，並延緩挫曲行為的發生。近年工程師開始將核心混凝土納入實際承重單元。CFT柱受力後，混凝土潛變就會隨時間持續發展，而柱構件為了保持其斷面力平衡，混凝土會將承擔的部分軸力移轉至鋼管，這些移轉量可能會使鋼管降伏，影響結構物的安全。此外，低水膠比的高強度自充填混凝土，也會產生大量自體收縮，使構件內混凝土及鋼管間應力移轉現象愈嚴重。本研究以有限元素分析軟體ABAQUS建置三維鋼管混凝土柱模型，選擇可反映台灣混凝土特性之B4-TW潛變收縮模式，研究混凝土潛變及自體收縮引致之構件內部應力移轉的情形。模擬結果顯示，在初始鋼骨應力設定為0.6f_y的情況下，無論荷載是否偏心，考慮混凝土潛變收縮效應的最終鋼應力皆有機會超出「鋼構造建築物鋼結構設計技術規範」檢核標準。而且在使用高強度自充填混凝土及構件高寬厚比的極端情況下，鋼應力可上升0.33f_y，將大幅超過原始設計值。未來設計應注重長期荷載效應，並考量混凝土長期變形對於鋼管應力的影響。
TitleStudy of the Influence of Creep and Shrinkage on Concrete-Filled Steel Tubular Columns and Design Suggestions
AuthorYa-Ju Yu, Jenn-ChuanChern, Wen-Cheng Liao
KeywordsCFT, creep, autogenous shrinkage, stress transfer,B4-TW creep and shrinkage prediction model
AbstractConcrete-filled steel tubular (CFT) columns show not only high strength and high ductility but also exhibit favorable seismic performance. The primary intent of concrete infill is to increase lateral stiffness of member and delay the local buckling of the steel tubular. Once concrete is subjected to load, development of concrete creep begins. In order to maintain the equilibrium of forces of CFT section, part of axial load of concrete will be transferred to steel tubular which leads to the growth of steel stress. Furthermore, high strength self-consolidating concrete (SCC) with low water-to-cement ratio intensifies the rise of steel stress in CFT columns on account of high autogenous shrinkage.A three-dimensional finite element model of CFT column, which takes account of the phenomenon of concrete creep and shrinkage, is developed to evaluate stress transfer between concrete and steel in ABAQUS. B4-TWcreep and shrinkage prediction model is also applied to reflect a characteristic of high amount of paste in concrete mix designs in Taiwan owing to the soft nature of coarse aggregates. The analysis results show that under the condition of initial steel stress of 0.6݂௬, the final steel stress of CFT column is probably not qualified according to “Design and Technique Specifications of Steel Structures for Buildings” owing to the long term deformation of infilled concrete whether the load is eccentric or not. In the extreme case of high concrete compressive strength of SCC and high diameter to thickness ratio, the steel stress significantly exceeds the original design value with 0.33݂௬. It is suggested that relevant specifications should be revised accordingly in Taiwan.
標題考慮鋼筋腐蝕影響之RC建築物耐震能力初步評估法
作者邱建國、詹宗翰、蔡宜靜
關鍵字初步耐震能力評估、目視調查、劣化度、鋼筋腐蝕
摘要本研究參考過去計劃成果以建立鋼筋腐蝕構件之力學評估模型，對腐蝕構件之塑鉸容量進行折減，除進行相關試驗資料之比對與驗證外，根據文獻所收集一般典型校舍及街屋的常用構件尺寸及斷面配筋，計算柱構件於不同劣化程度下之強度折減係數，提供評估人員搭配既有之初步耐震能力評估法使用。換言之，評估人員可參考RC建築物耐久性能診斷技術手冊之建議，依目視調查構件外觀之劣損以判定其劣化程度，並參考本文建議之折減係數修正其強度。本文最後以一既有校舍為範例，考量構件於不同劣化程度下之耐震能力，以國震中心所建立之TEASPA搭配結構分析軟體ETABS進行詳細評估，並與本研究所提供之初步耐震能力評估進行比對，以了解其合適性。
TitlePreliminary Seismic Performance Evaluation Method of RC Buildings Considering the Corrosion Effect of Reinforcement
AuthorChien-Kuo Chiu, Zong-Han Jhan, Yi-Jing Cai
KeywordsPreliminary seismic performance evaluation, Visual inspevtion, Deterioration de gree, Corroded reinforcement
AbstractThis research establishes a mechanical evaluation model of a corroded RC member and reduces its plastic hinge capacity on the basis of the past research project. In addition to do the comparison and verification with the relevant experiment data, this research collects the general information of the size of column members and reinforcement arrangement in a typical reinforced concrete building and street house for investigation on the reduction factor of strength. Restated, the reduction factor of strength can be used to consider effect of the deterioration or corrosion in the strength or seismic capacity for a corroded RC column member. Therefore, this work can provide a preliminary seismic performance evaluation method for a corroded RC building structure. Additionally, for a corroded column member, its reduction factor of strength is determined based on the deterioration degree, which can be judged based on the visual inspection of deterioration following the technical textbook of the durability assessment of deteriorating RC building structures. Finally, taking an existing school building for an example, TEASPA which is established by NCREE is used to evaluate the seismic performance considering the corrosion and verify the application of the proposed preliminary seismic performance evaluation method for a corroded RC building structure.
標題以2018花蓮地震震害建物探討耐震初評方法之有效性
作者杜怡萱、葉桐
關鍵字震害，耐震評估，初步評估，鋼筋混凝土
摘要本研究蒐集2018年0206花蓮地震中12棟不同震害程度之建物資料，應用於三種國內現行耐震初步評估方法，以探討其有效性及合理性。三種耐震初評方法包括：鋼筋混凝土建築物耐震能力初步評估（PSERCB）、國家地震工程研究中心（NCREE）校舍耐震初評及街屋耐震快評；評估結果顯示，三種初評方法皆能大略篩選出耐震能力有疑慮之建物，各初評方法之評估結果與震害等級之相對關係亦大致符合，但皆呈現較保守之趨勢。各建物之三種初評結果大多相近，僅有二棟建物之NCREE街屋快評結果與另外兩種方法出現差異，且皆顯示PSERCB及NCREE校舍初評較NCREE街屋快評更為保守。
TitleVerification of Preliminary Seismic Evaluation Methods Using the Damaged Building Data of  2018 Hualien Earthquake
AuthorYi-Hsuan Tu and Tung Yeh
Keywordsearthquake damage, seismic evaluation, preliminary evaluation, reinforced concrete
AbstractData of thirteen buildings that damaged differently in the 2018 Hualien earthquake were collected and used to verify three preliminary seismic assessment methods. The three methods are all widely used in Taiwan, including the Preliminary Seismic Evalureliminary seismic evaluation of RC Buildings (PSERCB), the Preliminary Seismic Evaluation Method for Typical Building Structures of Primary and Secondary Schools by NCREE, and the Preliminary Seismic Evaluation Method for Typical Street-houses by NCREE. Comparison between the evaluation results and the observed damage states of the thirteen buildings showed that all three methods can identify the buildings that were heavily damaged. All three methods can sort the buildings in an approximately reasonable order. However, all three methods tended to give conservative results. The results from different methods for the same building were usually close. Only two buildings obtained different results between the NCREE method for street-houses and the other two methods. The PSERCB and the NCREE method for school buildings showed more conservative results than the NCREE method for street-houses in the two buildings.
標題具多重耐震性能等級之機率式結構耐震評估法
作者盧煉元、蕭輔沛、湯宇仕、黃尹男、陳慶輝、李官峰
關鍵字耐震評估、機率式評估法、多重性能等級、隔震結構、性能設計法、增量動力分析、非線性動力分析、非線性塑鉸
摘要現有耐震評估法大多僅能用於評估建物之抗倒塌耐震能力，因其損傷準則係依據結構瀕臨倒塌之行為為主。此種耐震評估法並不適用於評估重要之功能性建物(例如：醫院、高科技廠)或隔震結構，因為此類建物係以強震中必須保有其功能性為其耐震目標之一。有鑑於此，本文乃針對具高度耐震性能要求之重要建物與隔震結構研議一套可考量多種性能目標之機率式耐震評估法及流程，此法乃參採FEMA356與ASCE 41-13之建議將建物之耐震性能等級分為：立即可用(IO)、生命安全(LS)、倒塌避免(CP)。各性能等級之損傷準則分為整體損傷準則與局部損傷準則，前者採用FEMA 356及PEER-TBI之標準；而後者則參採ASCE41-13所建議之構件損傷準則。根據這些損傷準則與增量動力分析之結果，再據以建立不同性能等級之易損曲線作為耐震評估之依據。若為隔震結構，則新增隔震極限(IL)之性能等級，以便將隔震層之安全性納入耐震評估中，其損傷準則係以隔震支承位移超過隔震設計規範所訂定之最大總位移 為依據。本文以一幢耐震力不足之老舊建物為例，並採用滑動隔震技術對該建物進行耐震補強，再以所建議之多重性能耐震評估法，對隔震補強前後結構之耐震性能進行評估與比較，以量化隔震補強對於不同耐震性能等級之效益。評估結果顯示，原先倒塌風險極高之原始建物，經過隔震補強後，各性能等級之損傷機率指標皆明顯下降。因此，本文提出之機率式耐震評估法適用於隔震或固定基礎結構，可供工程界完整評估建物於不同耐震性能等級中之風險。
TitleAn approach for probabilistic seismic performance assessment of buildings considering multiple performance levels
AuthorLyan-Ywan Lu, Fu-Pei Hsiao,Yu-Shi Tang,Yin-Nan Huang,Ching-Huei Chen, Kuan Feng Lee
Keywordsseismic performance assessment, probabilistic assessment, multiple performance levels, isolated building, performance design, incremental dynamic analysis, nonlinear time history analysis, plastic hinge
Abstract Most of current seismic assessment methods for buildings aim to evaluate the collapse risk of buildings, since the damage criteria of these methods are associated with the mechanism of building collapse. These methods may not be suitable for the assessment of functional facilities or seismic isolated buildings, whose performance objective is usually required to maintain their functionality after a strong earthquake. For this reason, this study proposes an approachfor probabilistic seismic assessment of buildings considering multiple performance levels. This approach adopts the performance levels defined by FEMA 356 and ASCE 41-13, namely, immediate occupancy (IO), life safety (LS) and collapse prevention (CP). For each performance level, both global and local damage criteria are defined according to FEMA 356 and ASCE 41-13, respectively. Based on these damage criteria together with the result of incremental dynamic analysis, the fragility curves for each performance level can be established for seismic assessment. For buildings with isolators, a performance level called isolation limit (IL) is also considered, in order to include safety of the isolation system in the assessment procedure. The damage criterion for IL performance level is defined as when the isolator drift exceeds the maximum total isolator displacement   given in the current isolation design code of Taiwan. For demonstration of the proposed assessment method, a 5-story old apartment building was consideredas an example. The building was retrofitted by using sliding isolators, and the seismic performance of the building before and after the implementation of isolation was evaluated using the proposed method and the results were compared, so that the benefit of retrofitting can be quantified. Theassessment results show that the retrofit with the isolators greatly reduces the damage probabilities of the building at all performance levels. This demonstrates that the proposed method can be applied to evaluate seismic performance of either fixed-based or isolated building with consideration of multiple performance levels.
標題醫院消防撒水系統耐震性能補強評估
作者蔡詠安、林凡茹、柴駿甫、張國鎮
關鍵字消防撒水系統、易損性分析、數值分析、簡化評估、耐震補強
摘要

建築結構之耐震性能在長年的研究，相較早期之建築物已有明顯的提升，在受震後的主要災害與經濟損失往往不是建築結構造成，而是非結構系統之破壞造成。醫院內非結構設備中的消防撒水系統受中小地震後，若發生天花板遭撒水頭碰撞發生擴孔、粉塵掉落，或於大震中，撒水系統之支撐破壞，失去支承能力，可能造成醫院中斷醫療機能，甚至發生淹水、火災等自發性災害。因此消防撒水系統需以性能設計法進行耐震評估，若耐震容量不足則須加裝補強裝置。

本研究以台大雲林分院為案例醫院，依據甲仙地震後的破壞機制，提出消防撒水系統耐震詳細評估法以及適合業界應用之簡化評估流程，並參考NFPA13(National Fire Protection Association, 2010)補強之建議，提出四種補強方案，依據各方案之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分析結果與適用性，並比較各方案之差異，以期做為消防管線系統耐震設計或補強之參考。

 
TitleSeismic evaluation and strengthening methods for fire protection sprinkler piping systems in hospitals
AuthorYung-An Tsai, Fan-Ru Lin, Juin-Fu Chai, Kuo-Chun Chang
KeywordsFire protection sprinkler system, fragility curve, numerical analysis, simplified assessment, seismic strengthening design
Abstract

In recent years, due to the vigorous development of performance design concepts, the seismic capacity of critical building structures (such as hospitals and high-tech factories) has been improved, and the major disasters and economic losses caused by the earthquake have changed from structural to non-structural systems, which include piping systems.

This study takes the medium-scale hospital in Southern Taiwan as an example to discuss the effects of installing strengthened elements on sprinkler piping systems which recommended by NFPA13. First, this research uses detailed analysis results to construct the fragility curves, and compares the fragility curves between before- and after-strengthened systems. Second, according to the dynamic characteristics of the sprinkler piping system, the simplified assessment method of original system and strengthened system are proposed in this study. It provides engineers with an alternative, rapid and approximate judgment in the seismic performances of piping systems based on in-situ observations and generic floor response spectrum.