第二十九卷第四期 (期別116) (103年)

作者:

第二十九卷第四期 (期別116) (103年)

標題改進局部柔度法於梁結構損傷診斷之研究
作者許丁友、蕭勝元、廖文義
關鍵字局部柔度法、擬局部柔度法、梁結構、損傷診斷、健康診斷
摘要局部柔度法(Local flexibility method)主要是藉由量測模態參數便可判斷梁結構之局部剛度變化。該方法基本條件之一，係使用－ 虛力使其所導致之應力在局部結構區域不為零， 其他區域為零；本研究提出擬局部柔度法(Pseudo local flexibility method)，係打破此一基本條件，使其使用之虛力導致應力在局部結構區域產生集中應力，並於其他區域也有微小應力。本硏究將擬局部柔度法應用於超靜定梁結構上，且利用數值模擬與實際試驗進行驗證，結果顯示，擬局部柔度法於少量模態的情況下，能更準確地診斷超靜定梁結構之損傷位置及程度。
TitleA Study on Damage Detection of Beam Structures Using the Pseudo Local Flexibility Method
AuthorTing-Yu Hsu, Shen-Yuan Shiao, Wen-I Liao
KeywordsPseudo local flexibility method, beam structure, damage detection, health monitoring
AbstractThe local flexibility method, which can determine local stiffness variations of beam structures by using measured modal parameters, is one of the more promising vibration-based approaches. The local flexibility method is founded on “local” virtual forces that cause nonzero stresses within a local part of the structure. In this study, this basic rule has been broken. The “pseudo-local” virtual forces that cause concentrated stresses in a local part and nonzero stresses in the other parts of a structure are employed. The theoretical basis of the proposed “pseudo local flexibility method” (PLFM) is derived. The effects of the number of modes on the damage detection results are studied using both numerical and experimental hyper-static beam models. The results show that significantly fewer modes are required for the PLFM to estimate the damage location and extent with acceptable accuracy. Therefore, the feasibility of the PLFM is higher because only a limited number of high quality modes can be identified in real world applications.
標題實尺寸高強度鋼筋混凝土梁之剪力裂縫行為研究
作者邱建國、陳崇慶、林芳慶、紀凱甯
關鍵字高強度、鋼筋混凝土、剪力裂縫、梁試體、殘留裂縫寬度、使用性能、修復性能
摘要本研究共進行十組四點荷重之簡支梁試驗(跨深比為3.33)，其中八組於左右兩端之等剪力段，配置不同之箍筋間距(200 mm 及300 mm)，剩餘兩組則無配置箍筋。壓力筋配置均為2 根，拉力筋則分別以8 根及12 根進行配置，且均為D25 之SD685 鋼筋，斷面尺寸均為400 mm(寬)×700 mm(深)，保護層厚度均為40 mm，箍筋採用D13 之SD420W 及SD785 鋼筋。依本研究實驗結果可知，就長期荷重(靜載與活載作用)下之使用性能確保而言，梁長期容許應力值可取ACI 318 -11 所建議混凝土剪力強度之0.75 倍。就短期荷重(中小規模地震)下之修復性能而言，本研究擬建議採用ACI 318-11 之混凝土剪力強度計算公式進行此性能點檢核。就高強度鋼筋混凝土梁構材而言，依本研究試驗結果可知其受力後之剪力裂縫殘留總寬度與最大寬度比值約為4.5；為保守起見，本研究建議該比值可取4.0 以進行分析時殘留剪力裂縫最大值推估。此外；尖峰變形角時剪力裂縫最大寬度與殘留最大寬度之比值，本研究建議高強度鋼筋混凝土梁之適用值為2.5。
TitleStudy on the shear cracking behavior of the full-size high strength reinforced concrete beams
AuthorChien-Kuo Chiu, Tsung-Ching Chen, Fang-Ching Lin and Kai-Ning Chi
Keywordshigh strength, reinforced concrete, shear crack, beam specimens, residual crack width, serviceability, reparability
AbstractThe main propose of this work is to investigate the shear crack development and suggest the design formulas that can ensure serviceability and reparability for shear-critical high-strength reinforced concrete (HSRC) beam members based on the experimental data of ten full-size simple-supported beam specimens (Span-depth ratio is 3.33). According to the experimental results, the design formulas that can ensure the serviceability and reparability are recommended for shear-critical HSRC beam members. Based on the crack development of each specimen, the average ratio of the residual total shear crack widths to the residual maximum shear crack width for the HSRC beam specimens is approximately 4.5; then, in the crack-based assessment, this work recommends setting the ratio as 4.0 to estimate residual maximum shear cracking. Additionally, the ratio of maximum peak shear crack width to residual maximum crack width, it can be increased by shortening stirrup spacing and increasing stirrup strength, and its overall average value is 2.44. This work suggests the applicable value of a HSRC shear-critical beam to be 2.5. Besides of the post-earthquake damage assessment, these results can also be used to build the performance-based design for HSRC structures.
標題預鑄梁與場鑄樓版間之混凝土冷縫界面對T型梁耐震行為影響
作者王勇智 、鄭智仁
關鍵字施工冷縫、界面剪應力、T 型斷面梁、耐震行為
摘要本實驗主要是針對T 型懸臂梁進行耐震行為分析，乃利用有或無預鑄施工冷縫T 型梁，針對不同剪力跨度(a/d=2.44 與a/d=5.46)進行討論。一般冷縫界面剪應力檢核之經驗公式由單向荷載實驗得來，並未探討其在反覆地震力作用下是否適用，這也是本文研究目的。由實驗結果得知，有預鑄施工冷縫的T 型短梁比一體澆置試體更易發生冷縫界面滑移。當剪力跨度越長，其抵抗滑移的面積越大，就越不易發生冷縫界面滑移。於負彎矩受力時，版筋受拉之有效版寬貢獻，有預鑄施工冷縫的T 型短梁為一體澆置試體的1.4 倍。另外，由T 型短梁冷縫界面剪應力分析結果得知，當量測之冷縫界面滑移量達0.5mm 時，平均界面剪應力則達0.2f’c ，與一般規範經驗公式上限值相當，應可作為冷縫界面剪應力耐震檢核標準。
TitleThe Effect of the Construction Joint Created between Precast Beam and Cast-in-Place Slab on the Seismic Behavior of Reinforced Concrete T-Beams
AuthorYung-Chih Wang, Jhih-Ren Jheng
KeywordsConstruction Joint, Interface Shear Stress, T-Beams, Seismic Behavior
AbstractThe purpose of the experimental study is to observe the seismic behavior of T-shaped cantilever beams. The study investigates the effect of construction joint and shear span (a/d=2.44 and a/d=5.46 ), and verifies the current design equations obtained from monotonic loading experience for evaluating interface shear stress. The test results indicate that the T-shaped short beam with construction joint slipped more obviously at the interface than the beam without construction joint. According to test results, in the negative moment when the slab bars stress in tension, the effective width of T-beam flange with construction joint is 1.4 time wider than the beam without construction joint. In the comparison between slender beams and short beams it was found that slender beams had less cold-joint slip effect than short beams. This is because the area of shear resistance at interface for slender beams is larger than short beams.
標題低矮型街屋耐震能力快速評估法之開發與驗證
作者邱聰智 、黃世建 、宋嘉誠 、鍾立來
關鍵字街屋、臨街店鋪住宅、快速評估、耐震評估、鋼筋混凝土
摘要街屋之數量龐大，很難全面進行專業之耐震評估。若能經由民眾的自主檢查，先篩選出耐震能力有疑慮的街屋，再交由專業者進行詳細評估，此較具可行性。故而一個簡單的街屋快速評估工具，確實有其必要。由於校舍與街屋具有相似的結構特性，且校舍已有大量之詳細評估結果，故可使用統計的方法，將校舍的耐震詳評結果應用在街屋上面。國家實驗研究院地震工程研究中心利用1,187 棟校舍耐震詳細評估資料庫，對每棟校舍的總樓地板面積、柱量以及經詳細評估後得到的耐震性能地表加速度進行統計分析，獲得每棟校舍之柱量比與耐震性能的關係。再以等值柱量的轉換概念，將磚牆及RC 牆對耐震性能的貢獻予以適度考量，因而發展出低矮型鋼筋混凝土建築物的耐震能力快速評估方法。本研究利用過去地震勘災紀錄，建立59 棟低矮型鋼筋混凝土建築震損資料庫，並以此震損資料庫驗證本快速評估法，驗證結果顯示震損程度為中害以上者，評估結果皆為耐震能力有疑慮。然而快速評估結果為耐震容量不足者，仍有一部分屬於小害以下，顯示本方法確實具有篩選性及保守性。以本方法對145 棟台灣典型街屋進行快速評估，約有四成的街屋須後送進行專業詳細評估。因此本方法可做為民眾住家自主檢查之工具，協助其篩選出耐震能力可能有疑慮之街屋，再尋求專業之詳細評估與補強設計，而為一個經濟可行的做法。
TitleSeismic rapid evaluation of low-rise street house
AuthorTsung-Chih Chiou, Shyh-Jiann Hwang, Jia-Cherng Song, Lap-Loi Chung
Keywordsstreet house, low-rise RC building, seismic rapid evaluation, reinforced concrete
AbstractIt is extremely difficult to carry out the seismic evaluation by professionals for all the street houses due to huge volume in Taiwan. Therefore, rapid evaluation carried out by owners as a preliminary screening can be a feasible scheme. Those buildings labeled with safety concern by rapid evaluation can be further evaluated by professionals. Since the school buildings and the street houses in Taiwan share the same structural characteristics, the empirical formula of seismic capacity for school buildings obtained through detailed evaluation can be applied to street houses. Based on the seismic evaluation data of 1,187 school buildings of the database collected by the National Center for Research on Earthquake Engineering, an empirical formula of the performance ground acceleration and the column-to-floor area ratio was established. The cross sectional areas of brick infill and RC wall can be transformed into the equivalent area of column according to their seismic capacities. Consequently, the performance ground acceleration of a low-rise street house can be rapidly evaluated by the ratio of column sectional area to floor area of building. The seismic rapid evaluation method has been verified by the data bank of damaged buildings collected through earthquake reconnaissance. The seismic capacities obtained from the rapid evaluation method correlate well with the damaged status of low-rise buildings. In general, the rapid evaluation method is conservative but still possesses a screening capacity. This paper presents a method for building owners to roughly evaluate the seismic capacity of their buildings by themselves.
標題醫院消防撒水系統機械式接頭之耐震行為與評估分析
作者林凡茹 、 張國鎮 、 黃振綱 、 柴駿甫
關鍵字消防撒水系統、機械式接頭、溝槽式接頭、螺紋接頭、擬靜態實驗、耐震性能評估
摘要醫院等重要建築耐震性能設計目的即為於強震後維持使用機能。然而國內外重要建築之消防撒水系統抗震經驗顯示，消防撒水管線系統一旦於某處輕微震損而發生洩漏，隨即因工作水壓導致消防水大量外流，釀成淹水等二次傷害，迫使重要建築中斷其機能。其中，機械式接頭(含螺紋式、溝槽式接頭)易為其管線系統的耐震弱點之一，然國內外工程界甚少關於消防管線系統機械式接頭性能設計所需之易損性實驗數據、元件非線性行為等相關研究。本研究針對國內醫院消防管線機械式接頭常見之規格，執行螺紋式與溝槽式接頭擬靜態實驗，並以靜力與動力分析進行管線系統初步評估，比較其受震行為及容量，以做為醫院等重要建築消防管線性能設計之參考。
TitleSeismic behavior and evaluation of mechanical fittings for fire protection sprinkler piping systems in hospitals
AuthorFan-Ru Lin, Kuo-Chun Chang, Jhen-Gang Huang, Juin-Fu Chai
Keywordssprinkler piping systems, mechanical fittings, grooved couplings, screwed fittings, quasi-static testing, seismic performance evaluation
AbstractBased on the experiences learned from recent earthquakes, it is recognized that the immediate operation of a hospital after strong earthquakes relies heavily on the functional integrity of critical nonstructural components. However,from the literature review of earthquake damages, the reduction of medical functionality has been caused by serious flooding due to the damage of mechanical fittings (including grooved couplings and screwed fittings) of sprinkler system. Hence, the objective of this paper is aimed to investigate the seismic behavior of mechanical fittings to improve the seismic performance of sprinkler systems effectively. The seismic capacities of mechanical fittings in pair with various pipe dimensions were studied through quasi-static tests under cyclic pure-bending loads. The small-bore fittings were further studied to the combined shear and bending effects. Based on the test results, the seismic performance evaluations for vertical and horizontal piping systems were implemented through static and dynamic analyses respectively.