第三十一卷第三期 (期別123) (105年)

作者:

第三十一卷第三期 (期別123) (105年)

標題台灣混凝土彈性模數建議公式研究
作者廖文正、林致淳、詹穎雯
關鍵字混凝土、彈性模數、粒料、抗壓強度
摘要混凝土為由水泥、水及粗細粒料所組成之複合材料，故其彈性模數高低受組成材料等因素影響甚鉅。關於混凝土彈性模數的計算，台灣主要是參照內政部營建署頒佈之「混凝土結構設計規範」，其公式內容是根據美國混凝土學會ACI 318 而定；但從以往研究發現，台灣相較於美國的混凝土彈性模數有明顯偏低的趨勢。有鑑於混凝土彈性模數在工程設計應用上的重要性，以及近年添加高摻量飛灰、水淬高爐爐碴粉等卜作嵐摻料的高性能混凝土被廣泛地使用，本研究乃從混凝土的組成出發，探討影響彈性模數之因子，而後針對台灣本土混凝土材料，蒐集台灣學術機構及現地試驗之彈性模數資料，進行統計迴歸與分析。根據研究成果，本研究建議將ACI318 之彈性模數預測公式乘上一修正因子0.8，適用範圍為抗壓強度在210kgf/cm2~840 kgf/cm2 間之混凝土，除了易於業界計算外，並可反映台灣混凝土彈性模數偏低的事實，並做為未來工程規範修訂的參考。
TitleA Practical Equation for Elastic Modulus of Concrete in Taiwan
AuthorW.-C. Liao, C.-C. Lin, Y.-W. Chan
KeywordsConcrete, Elastic Modulus, Aggregate, Compressive Strength
AbstractConcrete is a composite material consisting of water, cement, fine and coarse aggregates. The elastic modulus of concrete is highly affected by the properties of its components. The estimation of elastic modulus of concrete in Taiwan is mainly referred to the empirical equation provided in America Concrete Institute, ACI 318. However, it can be found that the elastic modulus of concrete in Taiwan is considerably lower than that in US according to the experimental results due to differences of aggregate properties. The aggregate phase is predominantly accounted for the elastic modulus of concrete. In addition, notable amounts of pozzolanic materials, such as fly ash and slag, are widely used in concrete mixtures in Taiwan. Since the elastic modulus directly influences the stiffness of RC structures, a more accurate prediction of the elastic modulus of concrete in Taiwan to reflect all these characteristics is essential. This paper proposes a formula to estimate the elastic modulus of concrete in Taiwan by collecting and analyzing the related test data. The parametric analysis is also carried out to verify the validity of this formula. This practical formula of elastic modulus of concrete has good agreement with that obtained from the experiments.
標題以性能為導向之二階段隔震設計法
作者盧煉元、王亮偉、陳慶輝、李官峰、李姿瑩、蔡諄昶
關鍵字 
摘要結構隔震技術為近年來發展極為快速的耐震新技術之一，可大幅提升結構之耐震性能，我國目前已有隔震設計規範可供依循。不過，現行隔震規範僅提供通用之公式，可用以決定總體隔震系統參數，但並無法用以設計個別隔震支承之參數。因此，傳統隔震設計流程係工程師依經驗選擇隔震支承參數，再利用規範公式進行隔震結構之設計，由於隔震支承大多為非線性元件，若設計結果未能滿足耐震需求，則必須經過多次重複的試誤及迭代過程，方能完成設計並決定隔震支承之參數。為簡化設計流程，本文乃提出「以性能為導向之二階段隔震設計法」。此法以不超過最大容許上傳地震力與容許隔震位移作為雙重性能目標，在無需迭代的情況下，即可決定出滿足此二項性能目標之隔震支承參數。本文方法主要分為二個設計階段，第一階段為線性隔震設計，主要係在滿足預設性能目標條件下利用規範公式以決定線性化等效隔震系統參數，亦即：有效週期與有效阻尼。而第二階段為非線性隔震設計，主要是由第一階段所得之線性化系統參數推求個別隔震器之非線性支承參數，例如：LRB 支承之降伏後勁度及降伏強度等。為方便實務之應用，文中詳細推導各階段所需之輔助設計用公式，同時亦列出詳細之設計流程及步驟。文末更以之一棟含有LRB 隔震支承之五層樓RC 建物為案例，以示範如何應用本文建議之設計方法及流程，在無需迭代及試誤計算的情況下獲得個別LRB 之支承參數，此組參數並可同時滿足預設之雙重性能目標。
TitlePerformance-oriented two-stage design method for base-isolated structures
AuthorLyan-Ywan Lu, Liang-Wei Wang, Ching-Huei Chen, Kuan Feng Lee, Tzu-Ying Lee, Chun-Chung Tsai
Keywordsbase isolation, isolation design, performance objective, allowable isolator displacement, allowable base shear
AbstractBase isolation is an effective means for improving seismic resistance capacity of structures. Design codes for base isolation have been given in many countries for many years. However, most of existing codes only provide generic formulas that determine the parameters of an isolation system as a whole, rather than the parameters for individual isolators. Consequently, design engineers have to perform the design task based on the isolator parameters selected according to past experience. Moreover, since most of existing isolators are nonlinear devices, conventional design methods usually involve iteration and trial-and-error procedure if certain performance demand has to be satisfied. In order to simplify the design procedure so the tedious iteration procedure in a conventional design approach can be averted, in this paper, a performance-oriented two-stage design method is proposed. Without iteration, this method is able to determine a set of isolator parameters that meet the two pre-selected performance objectives, namely, the allowable isolator displacement and base shear. The proposed method includes two design stages. In the first stage, the formulas specified in the current design code are employed to compute the linearized parameters of the whole isolation system, i.e., the effective period and effective damping, so that the two performance objectives can be satisfied. Based on the linearized parameters determined in the first stage, in the second stage, the nonlinear parameters for each individual isolator, such as the yield force and post-yield stiffness in a LRB isolator, are computed. For the convenience of applications, in this work, the complementary design formulas are derived and design steps are also outlined. Finally, the feasibility of the proposed design method is demonstrated by an example that involves a 5-story RC building isolated by LRB isolators.
標題採最佳化摩擦係數設計公式之隔震實務設計流程
作者王勝宣、蔡易佑、鍾立來、楊卓諺、高培修
關鍵字鋼筋混凝土、開孔牆、側力位移曲線、剪力強度、剪力變形
摘要由耐震設計中反應譜的觀念得知，當結構系統之週期較長時，有較低之設計地震力。隔震系統乃呼應此觀念，藉由延長結構系統之週期來降低上傳之水平地震力。摩擦係數在摩擦消能隔震系統扮演相當重要的角色。摩擦係數過低或過高，皆會提高上傳之地震力，隔震層設計位移則是隨著摩擦係數提高而降低，因此摩擦係數之決定相當重要。然而，目前業界通常是仰賴經驗以決定摩擦係數，而非一套有系統之方法。此外，由於地震震度與震波形式之不確定性，結構物於使用年限之間有可能碰到尖峰地表加速度(peak ground acceleration, PGA)更甚於設計地震之大地震，或是具低頻特性之近斷層震波。因此，本文嘗試將本文作者所發表之摩擦係數最佳化公式融入業界習用之隔震設計流程，是為摩擦係數最佳化隔震設計流程。為驗證最佳化流程之效果，本文考慮一假想隔震案例，並以設計地震、1.5倍設計地震、近斷層地震當作輸入，執行歷時分析，來驗證隔震效果及隔震層位移是否超過隔震位移限制。分析結果顯示，最佳化設計流程於三種外力下皆能有效降低加速度反應，但當外力為非設計地震力時，位移反應可能會超過隔震位移限制，代表最佳化流程可能無法滿足需求，因此本文嘗試改變設計流程之邏輯。首先固定位移，而後直接代入非設計地震之反應譜係數進行設計，此為修正最佳化隔震設計流程。本文亦以假想隔震案例進行設計，再以非設計地震力當作輸入執行歷時分析。由模擬結果可知此修正設計流程具有不錯的減震效果，隔震層最大位移反應亦小於隔震位移限制。摩擦係數最佳化設計流程相對於業界現行之設計流程僅多增加一步驟，並不會大幅影響工程師之設計習慣，但卻能作為工程師選用參數的依據。而修正最佳化隔震設計不僅步驟簡潔且又針對非設計地震需求設計，故本文認為此流程可以信賴。
TitleStructural Isolation Design Procedure with Optimal Design Formula of Friction Coefficient
AuthorSheng-Hsuan Wang, Yi-YoTsai, Lap-Loi Chung, Cho-Yen Yang, Pei-Shiou Kao
Keywordsisolation systems, frictional coefficient, optimal design procedure, isolation systems simulation
AbstractAccording to the concept of earthquake response spectrum, the structure which equips with isolation system reduces seismicforce by extending the period.For isolation design, the friction coefficient is one of the main design parameters. Based on the experience, the isolation displacement get lower with larger friction coefficient, however, the structural acceleration get larger with lower or larger friction coefficient.In the conventional isolation design procedures, the energy dissipation parameters, like friction coefficient, is not determined by some certain criteria but engineers’ practical experience. Because structure may suffer nearfult earthquake orearthquake of which intensity is larger than design earthquake. This article incorporates the optimal friction coefficient into isolation design process which called optimalisolation design process of friction coefficient. In order to verify effect of the process, the article choosesdesign earthquake, 1.5 times design earthquake and nearfult earthquake as input to do time history analysis in an imaginary case. The simulation result indicates that structural acceleration reduce effectively but isolation displacement may be larger than displacement limit except under design earthquake. Therefore, the article change design logicthat fixes displacement first and designs with non-design earthquake response spectrumto develop modified optimal isolation design process and chooses non-design earthquake as input to do the timehistory analysis in an imaginary case.According to the analysis results, the isolation displacement will be lower than design displacement andstructuralacceleration reduce effectively. Because the difference between the optimal design procedures of friction coefficient and the conventional one is insignificant, engineers will feel comfortable to adopt the optimal design procedures to determine isolation parameter. The modified optimal isolation process’s steps are concise and base on non-design earthquakeresponse spectrum, so the article refer the process as credible.
標題鋼筋混凝土開孔牆受剪破壞之側力位移曲線預測
作者黃世建、林永健、蔡仁傑、曾建創、涂耀賢、蕭輔沛
關鍵字鋼筋混凝土、開孔牆、側力位移曲線、剪力強度、剪力變形
摘要低矮型鋼筋混凝土(Reinforced Concrete; RC)住宅建築使用了大量的開孔RC 牆，但由於工程界對開孔RC 牆之耐震行為不甚了解，故於耐震評估與設計時，常將開孔RC 牆之貢獻予以忽略或是過度折減使用。此將造成住宅建築之耐震能力被嚴重低估，這對低矮型住宅結構之耐震設計、評估與補強工作有不利之影響。本文對開孔RC 牆在剪力破壞控制下之側力位移曲線提出建議，其係以開裂點、強度點及崩塌點為轉折之曲線。經與反復載重之開孔RC 牆實驗比對，得知本文建議之側力位移曲線，確實能合理反映開孔RC 牆之耐震行為。本文建議的分析程序已大幅簡化，可以手算執行，非常適合工程實務之應用。若對低矮型RC 建築執行側推分析，而將開孔RC 牆模擬為等值寬柱時，本文建議之側力位移曲線，可供該寬柱剪力塑鉸之模擬使用。
TitlePrediction of Lateral Load Displacement Curve of RC Wall with Openings Failing in Shear
AuthorShyh-Jiann Hwang, Weng-Kin Lam, Ren-Jie Tsai, Chien-Chuang Tseng, Yaw-Shen Tu, Fu-Pei Hsiao
Keywordslateral load displacement curve, reinforced concrete, shear deformation, shear strength, wall with opening
AbstractThere are plenty of RC walls with openings in the low-rise residential buildings. Due to unawareness of the behavior of RC walls with openings, their effects are often ignored or undervalued during seismic assessment and design. In consequence, the seismic capacity of residential buildings is greatly underestimated, which is detrimental to the work of seismic design, evaluation and retrofitting for the low-rise residential buildings. In this paper, a lateral load displacemen tcurve of the RC walls with openings subjected to shear failure is proposed. The turning points in the structural behavior are defined as shear cracking, shear strength and collapse point. The proposed model correlates well with the available test results of RC walls with openings. Calculations of the proposed model are greatly simplified to fit in the purpose of design in practice. For the pushover analysis, the proposed model can simulate the properties of shear plastic hinge of the RC walls with openings.
標題不同橋梁耐震評估方法之比較
作者黃仲偉、洪曉慧、陳常麒
關鍵字性能設計、側推分析、多跨橋梁、動力歷時、耐震評估
摘要結構的「耐震設計」與「耐震評估」長久以來一直是國內推廣永續發展之重大課題，歐、美、日本在內的許多國家皆已採用性能設計理念的精神與內涵於新世紀技術規範。國內亦於民國98 年起推動本土化公路橋梁耐震性能設計規範，目標為控制橋梁結構於各等級地震作用下之使用性、可修復性與安全性。確保新建橋梁在不同等級地震作用下達到預期耐震設計目標之可靠度，降低橋梁地震中的受損風險。本文旨在介紹公路橋梁耐震能力設計規範草案中的耐震評估方法，並以四座多跨連續數值橋梁為探討對象。利用非線性側推分析建立橋梁整體容量曲線，分別以不同的耐震評估方法計算橋梁性能點，由性能點反推橋梁上部結構整體之側向位移。最後以非線性動力歷時分析所得之橋梁上部結構整體之側向位移作為基準，比較不同耐震評估方式所得結果的差異。希冀透過此研究可讓國內實務單位對於不同橋梁耐震評估方法能有初步的認識。
TitleComparison of different bridge seismic assessment methods
AuthorChang-Wei Huang, Hsiao-Hui Hung, Chang-Chi Chen
Keywordsperformance design, pushover analysis, multiple span bridge, dynamic time history,seismic assessment
AbstractStructural seismic design and seismic assessment are important issues in the sustainable development. Today, the concepts of performance-based design have been adopted in the building codes of European Union, Untied of States, Japan and other advanced countries. As a result, the performance-based seismic design provisions and commentary for highway bridges has also been introduced in Taiwan from 2009. The aims of the new seismic design provisions are to ensure the serviceability, retrofit, and safety of highway bridges under seismic hazards. In addition, the new seismic design provisions focus on the real responses of structures suffer from different levels of earthquakes, which can guarantee the new bridges, according to the performance-based design, achieving the reliability of anticipated targets and decreasing the damage ricks. In this paper, the draft of the new seismic design provisions for highway bridges is introduced and compared with other two existed method (ATC-40 and refined seismic assessment method). Pushover analyses with uniform lateral load pattern for four numerical multiple-span bridges are carried out. Then the pushover curves are transformed to the corresponding capacity spectrum curve with multiple monitoring points. Then the performance points are obtained by three seismic assessment methods and can be used to estimate the maximum lateral displacements. Compared with the results from nonlinear dynamic analyses, one can know the differences between three seismic assessment methods.