第三十五卷第三期 (期別137) (109年)

作者:

第三十五卷第三期(期別137)(109年)

標題SM570M-CHW 高強度鋼箱型柱翼厚與梁翼板高程偏心對電熱熔渣銲破壞效應
作者黃昱竣、胡祐瑋、覃志光、蔡青宜、李昭賢、莊勝智、 林克強、蔡克銓
關鍵字鋼箱型柱、鋼梁柱接頭、SM570M-CHW 鋼、電熱熔渣銲、圓周刻痕拉伸試驗、鋼材破裂預測模型、有限元素模型分析、橫隔梁翼交疊高度
摘要箱型柱具雙強軸特性，在台灣鋼結構中應用普遍，為將梁彎矩傳入柱構件，箱型柱中與梁翼相對應之高程須置入內橫隔板，內橫隔板與箱型柱之銲接工法通常採用電熱熔渣銲（Electro-Slag Welding, ESW），而為減少柱斷面積，高強度 SM570M-CHW 鋼的應用也漸普及。本研究利用高強度鋼材探討箱型柱中 ESW 的耐震行為，並採用既有的鋼材破壞預測模型探討ESW 是否會破裂與破裂時機。本研究以 11 組 ESW 元件單向拉伸試驗與 4組實尺寸梁柱接頭反覆載重試驗探討柱翼板厚度與梁翼板偏心對於 ESW 破壞的效應，試驗結果顯示 ESW 元件僅受單向拉力作用時，只要「梁翼橫隔交疊高度」小於等於零，且偏心大於一倍柱翼板厚度，ESW 就會發生破壞；但「梁翼橫隔交疊高度」大於或等於 1/4 梁翼厚時，偏心超過一倍柱翼板厚度仍不會於 ESW 發生破壞。實尺寸梁柱接頭反覆載重試驗中則證明當柱翼板厚度由 25mm 提升至 45mm 時，ESW 由原先 3%層間位移角發生破壞改善至層間位移角達 5%尚未發生破壞。為探討 ESW 元件能否有效模擬梁柱接頭中的 ESW 銲道受力行為，本研究亦建立圓周刻痕試棒有限元素模型獲得材料參數之後，再進行 ESW 元件有限元素模型分析，並進行 ESW 關鍵區域破裂預測，結果顯示不論梁翼對 ESW 往梁腹方向亦或是反向偏心，有限元素模型皆能預測出 ESW 元件試體破壞時機且誤差小於 12%；進而建立實尺寸梁柱接頭有限元素模型模擬接頭內 ESW 銲道在反覆載重作用下之受力行為，結果顯示當柱翼板厚度由 25mm 增厚至 45mm 時，應力集中現象明顯減緩，且尖端開口位移下降至原先 1/3 倍，並可準確預測梁柱接頭內ESW 破壞時機。本研究亦以柱翼板厚度、梁翼板厚度及橫隔梁翼交疊高度為參數進行研究，探討不同參數配置對 ESW 銲道關鍵區域破壞時機之影響。分析結果顯示，當柱翼板厚度與橫隔梁翼交疊高度提升，以及梁翼板厚度減少時，可降低 ESW 開裂之機會。本研究建議柱翼板厚度宜大於或等於橫隔板厚度，且橫隔梁翼交疊高度不宜低於四分之一倍之橫隔板厚度，以避免 ESW 之脆性破壞。
TitleEffects of SM570M-CHW steel beam flange eccentricity and box-column flange thickness on electro-slag welding failure
AuthorYu-Jun Huang, You-Wei Hu, Chih-Kuang Chin, Ching-Yi Tsai, Chao-Hsien, Li,Sheng-Jhih Jhuang, Ker-Chun Lin, Keh-ChyuanTsai
Keywordssteel box column, SM570M-CHW steel, electro-slag welding, circumferentially notched tensile test, steel fracture prediction model, finite element analysis, overlapping distance of beam flange and diaphragm
AbstractSteel box columns are widely used in seismic steel building structures in Taiwan. In order to effectively transfer the beam-end moment to the column, diaphragm plates are welded inside the box column at the same elevations of the welded beam flanges. Electro-slag welding (ESW) procedure is common applied to attach the diaphragm plates to the column. Recently, the SM570M-CHW grade high strength steel is prevailingas it reduces the column sizes. In this study, four full-scaled welded SM570M-CHW steel beam-to-column (BC)joint specimens and eleven ESW component specimens were fabricated and tested. The key design parameters of these specimens include column flange thickness, beam flange eccentricity with respect to the diaphragm plate. This study investigates the applicability of stress modified critical strain and degraded significant plastic strain modelsin predicting the crack initiation fracture of the diaphragm-to-column ESW joint. The ESW component specimens were subjected to monotonic tensile loads, while the welded BC joint specimenswere subjected to cyclically increasing displacement to investigate the effects of beam flange eccentricity and column flange thickness on the ESW fractures. Test results show that when the ESW was subjected to monotonic tension only, it could fracture when the “overlapping distance of beam flange and diaphragm” (OD) was smaller or equal to zero. On the contrary, it remained intact even when the ODwas greater or equal to thickness of beam flange. Cyclic test results of the welded BC joints show that the connection with the 25mm thick column flange failed at the 3% inter-story drift (IDR) cycle, while the specimen with the 45mm column flange went through 5% IDR cycle without failure. The finite element model analysisresults show that when the column flange thickness increases from 25mm to 45mm, the stress concentrations are reduced and the crack tip opening displacement is decreased by 3 times. This study also carried out parametric study, focusing on the effects of the column flange thickness, the beam flange thickness and the OD on ESW fracture. Results show that increasing the column flange thickness, or the OD and decreasing the beam flange thickness reduce the stress concentration near ESW. In order to avoid the ESW fracture, the results of this study suggest that column flange thickness be equal to or larger than diaphragm or beam flange thickness; and the ODbe larger than one quarter of the diaphragm or beam flange thickness.
標題地動特性預測模組與智慧型隔減震控制系統之研發
作者蕭迦恩、林光奕、林子剛、 盧煉元
關鍵字地表運動特性，支持向量機，隔減震控制，基因演算法，模糊控制
摘要近年來隔減震控制與地震預警的研究愈加受到重視，在地震工程領域中，地表運動特性除了常見的加速度、速度與位移的極值，還可分類為近斷層地表運動(near-fault ground motion)與遠域地表運動(far-field ground motion)。根據過去結構隔減震控制的相關研究，不同地表運動特性對於結構反應之控制結果影響甚鉅，故此研究試圖提出地表運動特性之預測模組，於地震主震波到來前預測此地震之地表運動特性，以優化隔減震之即時控制成效。本研究建立近斷層地表運動與遠域地表運動之資料庫，利用六項初達波特徵參數以及地表動態頻譜的高頻能量累加參數，以監督式機器學習—支持向量機建立地表運動特性預測模組。為了進一步開發智慧型隔減震即時控制系統，研究中採用槓桿式可變勁度隔震系統(Leverage-type Stiffness Controllable Isolation System, LSCIS)作為隔減震原型機構，此半主動控制機構可透過調整其控制律之控制參數，改變有效隔震勁度以即時控制結構動態反應。本研究亦將數個相異類型且具指標性的地表運動所對應之控制參數透過基因演算法最佳化，並以模糊控制建立地表運動與控制參數之關係模型，開發出智慧型隔減震即時控制系統。
TitleDevelopment of Ground Motion Characteristics Prediction Module and its Application to the Control of Intelligent Isolation System
AuthorChia-En Hsiao, Kuang-Yi Lin, Tzu-Kang Lin, Lyan-Ywan Lu
KeywordsGround motion characteristics, Support vector machine, Structural control, Genetic algorithm, Fuzzy control.
AbstractIn recent years, researches on structural control combining earthquake early warning have been widely studied. In the field of seismic engineering, ground motions can be mainly classified into near-fault and far-field ground motions. While the ground motion characteristics have a great influence on control performance; however, the existing earthquake early warning system can only predict the peak ground acceleration, and the optimal control efficiency cannot be promptly achieved. Therefore, a prediction module for ground motion characteristics is proposed in this study. A database of near-fault ground motions and far-field ground motions is first collected, and the six p-wave features and the high-frequency energy accumulations of the ground dynamic spectrum are used to establish the ground motion characteristic prediction module by utilizing support vector machine. In order to develop the intelligent structural control system, the Leverage-type Stiffness Controllable Isolation System (LSCIS) is used as the structural control mechanism. The effective isolation stiffness of the LSCIS can be swiftly changed to control the dynamic response of the structure. The control parameters corresponding to different types of ground motion are optimized by genetic algorithm, and fuzzy control is adopted for the intelligent isolation system.
標題壓電調諧質量阻尼器於垂直振動減振與能量擷取
作者賴勇安、周維苓、鍾立來
關鍵字調諧質量阻尼器、壓電材料、能量擷取、垂直振動、最佳化設計
摘要近年來人類對於能源的需求持續攀升，然而為因應氣候變遷，將迫使減少石化能源的使用，因此尋求更多更環保的能量來源，以因應未來需求，為當前各國的研究重點之一。由於土木結構與材料技術的發展，結構物設計建造越趨經濟，橋梁結構重量漸趨輕量，外觀也逐趨細長，結構週期也隨之延長，使得橋梁結構也較易受人行等外力激振。土木工程師為了有效降低此振動量，逐以加裝調諧質量阻尼器（Tuned Mass Damper, TMD）的方式，透過調諧質量阻尼器的振動頻率與結構自然頻率調諧，吸收結構的振動能量，並透過自身之阻尼器來消散傳入之振動能。然此能量為一綠色能源，如能量就此消散，實為浪費，有鑑於此，本文研究「壓電調諧質量阻尼器 (Piezoelectric Tuned Mass Damper, Piezo-TMD)」，以壓電材料將吸收之機械振動能轉換為電能，以便進行能量擷取。本文首先提出壓電調諧質量阻尼器之模型，推導出壓電調諧質量阻尼器系統之運動方程式。與一般調諧質量阻尼器不同，壓電調諧質量阻尼器除了力學之運動方程式外，另有一電路方程式，且兩方程式互為耦合。本文之壓電調諧質量阻尼器設計目標為能量擷取的平均功率最大化，並以一人行橋結構進行數值模擬，結果顯示壓電調諧質量阻尼器具有與傳統調諧質量阻尼器相近之結構減振效果，並可將人行外力所引致之振動能轉為可再利用之電能。且模擬結果顯示，壓電調諧質量阻尼器除其機械之自然頻率需與結構相調諧外，其電路之自然頻率也需與結構調諧，方可使結構之振動能量有效利用共振效應轉移至電路上。
TitlePiezoelectric Tuned Mass Damper for Vertical Vibration Reduction and Energy Harvesting
AuthorYong-An Lai, Wei-Ling Chou, Lap-Loi Chung
Keywordstuned mass damper, piezoelectric material, energy harvesting, vertical vibration reduction, optimal design
AbstractIn recent years, the energy consumption has continually grown. However, due to climate change, the use of fossil fuel to generate electrical power forces to be reduced. Therefore, looking for environmental friendly energy sources is one of the current research priorities. Because of the development of civil engineering technology, the design and construction of structures turn into more economical. The weight of the bridge structure is becoming lighter, the appearance is accomplishing slender, and the structural period is therefore prolonged, making the bridge structure more susceptible to external forces such as pedestrian loads. In order to effectively reduce the vibration, civil engineers designed and installed Tuned Mass Damper (TMD). Through the tuning of the natural frequency of TMD to the structure, the vibration energy of the structure was absorbed and then dissipated by dashpot. However, this absorbed energy is a kind of green energy source to waste to be dissipated. In view of this, this article studies “Piezoelectric Tuned Mass Damper (Piezo-TMD)”, which uses piezoelectric materials to convert the mechanical vibration energy into electricity for energy harvesting. This research proposes the model and derives the equation of motion of the Piezo-TMD system. Different from the conventional TMD, Piezo-TMD has a circuit equation in addition to the mechanical equation, and these two equations are mutually coupled. The design goal of the Piezo-TMD in this paper is to maximize the average power for energy harvesting, and the numerical simulations are carried out with a pedestrian bridge structure. The simulation results show that the Piezo-TMD achieves the similar performance of vibration reduction as the conventional TMD and thus the vibration comfort requirement can be satisfied. Moreover, the vibration energy is further transferred to electricity for harvest to verify the feasibility of Piezo-TMD. In addition to tuning the mechanical natural frequency of the Piezo-TMD, the natural frequency of the circuit also needs to be tuned to the structure, so that the vibration energy of the structure can be effectively transferred to the circuit by using the resonance effect.
標題五螺箍筋柱之雙曲率反覆載重試驗與離散計算剪力模型
作者歐昱辰、李哲諺
關鍵字剪力強度、五螺箍、柱、離散計算剪力模型、反覆載重
摘要五螺箍筋運用在正方形斷面鋼筋混凝土柱已證實具有優於傳統方箍筋的圍束能力。本研究目的在於探討五螺箍筋之剪力強度，設計雙曲率反覆載重試驗，測試大型剪力破壞五螺箍柱與傳統方箍柱對照組。測試結果指出，箍筋體積比相同、鋼筋降伏強度與混凝土抗壓強度相似的情況下，五螺箍柱展現稍弱於傳統方箍柱的極限剪力強度，所有五螺箍柱過最大剪力強度後力量衰退速率皆小於傳統方箍柱。高軸力五螺箍柱之破壞模式為箍筋拉斷，而高軸力傳統方箍柱之破壞模式為彎鉤鬆脫導致過早破壞。本研究發展一套改進離散計算剪力模型用來計算五螺箍柱剪力強度。與試驗結果比較，改進離散計算剪力模型能保守估計五螺箍剪力強度，此外，本模型具有與規範剪力公式用於傳統方箍剪力強度之相似保守程度。
TitleDouble-curvature cyclic test of columns with five-spiral reinforcement and discreet computational shear strength model
AuthorYu-Chen Ou and Jhe-Yan Li
Keywordsshear strength; five-spiral reinforcement; columns; discreet computational shear strength model; cyclic test.
AbstractFive-spiral reinforcement has been proved to have superior confinement capability to conventional rectilinear hoops. The objective of this research is to investigate the shear strength of five-spiral reinforcement. Large-scale columns with five-spiral reinforcement and control columns with conventional rectilinear reinforcement were tested in this research using double-curvature cyclic loading. Test results showed that with the same volume of reinforcement and similar reinforcement yield strength and concrete compressive strength, the shear strength of columns with five-spiral reinforcement was slightly less than that with conventional rectilinear reinforcement. However, the strength degradation after the peak strength for columns with five-spiral reinforcement was slower than that for columns with conventional rectilinear reinforcement. Under high axial load, the failure mode of columns with five-spiral reinforcement was fracture of spirals.In contrast, the failure mode of columns with conventional rectilinear reinforcement was the loosening of hook anchorage of the reinforcement. An improved discreet computational shear strength model is developed in this research and validated by the test results. The model can be conservatively used for estimating the shear strength of five-spiral reinforcement. Moreover, the model shows a conservatism for estimating the shear strength of five-spiral reinforcement similar tothat shown by the code shear strength equations for conventional rectilinear reinforcement.
標題結合振形之微振索力估算法中量測點位配置對精度的影響
作者陳建州、吳文華、陳欣怡、 賴國龍
關鍵字微振法、索力估算、振形、有效振動長度、多點同步量測、量測點位配置
摘要為克服複雜錨定條件造成微振索力估算法的較大誤差問題，本研究團隊近年來提出一項創新的方法，藉由導入振形函數正弦分量的擬合來決定各振態有效振動長度以排除索力計算公式中複雜邊界條件的影響，而其關鍵則在如何經由多點同步量測精準重現振形函數之正弦分量。本文首先根據理論推導出的頻率方程式與振形函數闡述此一索力量測方法的基本原理；接著再進一步利用有限元素模型，於考慮實測作業限制條件下建立包括數目與間距等量測點位配置準則；最後則進行實驗室單根鋼絞線索力量測，充分驗證所擬定量測點位配置準則的適用性以及對應的索力估算精度。
TitleEffect of sensor deploymentonen on the accuracy of ambient vibration method incorporating mode shape functions for cable tension estimation
AuthorChien-Chou Chen, Wen-Hwa Wu, Shin-Yi Chen and Gwolong Lai
Keywordsambient vibration method, cable tension estimation, mode shape, effective vibration length, multiple synchronous measurements, sensor deployment
AbstractThe complicated boundary conditions resulted from the anchorage systems at both ends usually deteriorate the accuracy of the ambient method for cable tension estimation. Motivated by tackling such a problem, a novel method incorporating the mode shape functions was recently proposed by this research group. More specifically, the fitting for the sinusoidal components of mode shape functions was adopted to determine the effective vibration length for each mode such that the interference from the complicated boundary conditions can be eliminated. The success of this method is most critically decided by the accurate reproduction of the sinusoidal components of mode shape functions based on multiple synchronous measurements. The current paper first explains the basic concepts of this cable tension estimation method with the theoretically derived mode shape functions and frequency equations. The finite element models are further employed to evaluate the accuracy of this method and establish the guidelines for the preferred sensor deployment in measurement points and spacing with the consideration of practical measurement limitations. Finally, the applicability of the developed guidelines and the corresponding accuracy in tension estimation are verified by demonstrative laboratory experiments with a prestressed strand.