第三十三卷第四期 (期別132) (107年)

作者:

第三十三卷第四期 (期別132) (107年)

標題強脊結構系統之耐震行為研究
作者郭銘桂、林瑞良、蔡克銓
關鍵字層間位移角、廣義建築模型、強脊系統、非線性反應歷時分析
摘要為解決結構受震層間位移角分佈不均之問題，本研究希望利用簡化分析模型對強脊系統（strongback system）進行大量的參數分析，提出有效的設計參數。本研究以廣義建築模型（generalized building model，GBM）及含強脊系統之廣義建築模型（generalized building model with strongback，GBMSB）作為簡化的數值模型，針對在台北二區，第二類地盤的三、六、九和二十層建築進行參數分析。採用SRSS 振態疊加法估算最大彈性層間位移角，並利用層間位移角的標準偏差作為均勻度指標，評估層間位移角分佈之均勻性，使層間位移角的標準偏差為最小之設計為最佳設計。分析結果顯示強脊系統為純剪力型式，且其層勁度呈線性遞減，並且於一樓加勁的勁度分配法效果最佳。為了驗證參數分析之有效性，採用SAC 研究計畫中的九層鋼構造抗彎矩構架，和國家地震工程研究中心台南實驗室的三層鋼筋混凝土構架試體作為驗證例。將原始結構模型（分別稱為SAC9 和T3）、含最佳強脊系統之結構模型（分別稱為SAC9-SB 和T3-SB）、及含非最佳強脊系統之結構模型，分別利用PISA3D 結構分析程式進行非線性反應歷時分析。結果顯示配置最佳強脊系統之SAC9-SB 和T3-SB 層間位移角之標準偏差平均值最小，能使層間位移角分佈最為均勻。
TitleStrongback systems for enhancing the seismic performance of buildings
AuthorMeng-Kwee Kek, Jui-Liang Lin, Keh-Chyuan Tsai
Keywordsinter-story drift ratio, generalized building model, strongback, nonlinear response history analysis
AbstractIn order to reduce the variations of peak inter-story drifts occurred in earthquakes along the building height, this research conducts the parametric study of the buildings with strongback systems through simplified numerical models. The generalized building model (GBM) and generalized building model with strongback (GBMSB) are employed as the simplified numerical models in the parametric study. This study investigated 3, 6, 9 and 20-story buildings.The peak inter-story drift ratios along the building height are computed by using the response spectrum analysis method, in which the peak modal responses are combined according to the SRSS method. The optimization objective is to minimize the standard deviation of the peak inter-story drift ratios. The optimal stiffness distribution of a strongback is thus obtained.The results of parametric study show that when a pure shear-type strongback, whose first story is stiffened and its story stiffness decreases linearly along the height, the standard deviation of inter-story drifts is minimized. The effectiveness of the proposed method is verified by investigating one 9-story steel building and one 3-story reinforced concrete (RC) building.The 9-story steel moment resisting frame, designated as SAC9, was a prototype building located in Los Angeles adopted in SAC steel research project. In addition, the 3-story RC building, designated as T3,was tested using shaking table at Tainan Laboratory of National Center for Research on Earthquake Engineering. The optimal designs of SAC9 and T3 with the strongbacks are designated as SAC9-SB and T3-SB, respectively. Nonlinear response history analyses (NRHA) of SAC9, T3, SAC9-SB, T3-SB models and the others with different properties of strongback systems were conducted using PISD3D program. The NRHA result shows that SAC9-SB and T3-SB have smaller standard deviations than those using other strongback properties. The analysis results confirm the effectiveness of the proposed method in proportioning the strongback for buildings.
標題鋼梁接箱型柱之內橫隔斷裂試驗與有限元素模型分析研究
作者吳忠哲、李昭賢、蔡青宜、林克強、莊勝智、蔡克銓
關鍵字鋼箱型柱、電熱熔渣焊、鋼材斷裂預測模型、鋼梁柱接頭、有限元素分析、圓周刻痕拉伸試驗、電熱熔渣焊儲倉口
摘要鋼箱型斷面柱構件具有雙強軸的特性，因此國內鋼建築結構中應用非常普遍。為傳遞梁端彎矩至柱構件，箱型柱內與梁翼同高處須配置與梁翼同厚的橫隔板。內橫隔板與柱板間焊接常使用電熱熔渣焊(Electro Slag Welding, ESW)工法，此種焊道施作便利且效率高，已大量使用於國內鋼結構製造廠。然而，ESW 施做時的高入熱量恐導致其焊道及其周圍母材結晶過大與抗衝擊性質較差，此現象亦常導致梁柱發生非預期的脆性破壞。為避免ESW 發生脆性破壞及量化ESW 破壞之機制，本研究採用既有的鋼材斷裂預測模型，利用有限元素模型對試體進行斷裂預測分析。本研究進行三組梁柱接頭試驗，藉由變化試驗之載重歷時與ESW 施工儲倉口截面形狀，探討試體破壞時機並驗證鋼材斷裂預測模型之可行性。實驗結果顯示證實累積塑性應變大小確實影響其破壞時機；ESW 儲倉口截面由矩形變為喇叭口形時，顯示若增加ESW 之熔透範圍可增加接頭試驗耐震性能。為應用斷裂預測模型，藉圓周刻痕拉伸(Circumferential Notched Tensile, CNT)試驗與有限元素模型分析，將所得之材料參數對ESW 元件試驗與梁柱接頭試驗進行斷裂預測分析。分析結果顯示，ESW 之幾何形狀及相對位置對於破壞時機影響甚大，因此顯示破壞預測分析與CNT 試驗之可行性，以及焊道超音波檢測(Ultrasonic Test, UT)之重要性。
TitleFracture Tests and Finite Element Analysis of Diaphragm Connection in Steel Beam-to-Box Column Joints
AuthorChung-Che Wu, Chao-Hsien Li, Ching-Yi Tsai, Ker-Chun Lin, Sheng-Jhih Jhuang, Keh-Chyuan Tsai
Keywordssteel box column, electro-slag welding, heat affected zone, fracture prediction model, steel beam-to-box column connection, finite element model analysis, circumferential notched tensile test, ultrasonic test
AbstractSteel box columns are widely used in steel building structures in Taiwan due to the strong axes in two directions. In order to transfer the beam end moment to column, diaphragm plates of the same thickness and elevations as beam flanges are usually welded inside box column. Electro-slag welding (ESW) process is typically used in attaching the diaphragms to column flanges. This ESW process has been widely used in steel beam-to-box column joints in Taiwan because of its’ convenience and efficiency. However, ESW may increase the hardness of the welds and heat affected zones (HAZs), while reduce the Charpy-V Notch (CVN) strength in HAZ. This situation could cause the diaphragm to column flange weld to suffer premature fracture before a large plastic rotation is developed in beam-to-box column joints. In order to quantify the critical eccentricity and the effectiveness of predicting the fractures, this study utilizes the fracture prediction model and finite element model (FEM) analysis to correlate the test results. In this study, three beam-to-box column connection subassembly tests have been conducted with a different loading protocol or the shape of ESW chamber. Test results show that the fracture instances can be predicted based on the cumulative plastic deformation in the HAZs. Tests confirm that the possible fracture of the diaphragm to column flange welds can be mitigated by enlarging the chamber of the ESW. When the fracture prediction model is applied, the material parameters were firstly established from the Circumferential Notched Tensile (CNT) tests and FEM analysis. Subsequently, these parameters were used to predict the fractures observed in the ESW component tests and beam-to-box column connection subassembly tests. The fracture locations and instances can be reasonably well predicted by a suitable FEM model analysis. Thus, the effectiveness of CNT and the fracture model are confirmed. Analytical results also show fracture instances and locations are sensitive to the relative locations of the ESW and the beam flange. Thus, the importance of ultrasonic test in assuring the quality of the ESW is evident.
標題考慮塗裝系統更新週期影響之鋼構橋梁生命週期成本評估方法建構
作者邱建國、陳正誠、陳敏祐
關鍵字鋼構橋梁、劣化速率、生命週期維護成本、防蝕塗裝系統
摘要鋼構橋梁於維護階段主要之費用分為定期維護成本及防蝕塗裝成本。對於定期維護成本而言，本研究主要使用貝氏更新決定構件/元件劣化速率，並且推估不同維護週期下之費用分布，以選擇成本最小之定期維護週期。防蝕塗裝成本除材料費用外須考慮施工費用，本研究主要參考歷史資料，以建立防蝕塗裝工程洐生之施工機具與相關費用推估模式。此外，為使設定之塗裝系統更換週期更貼近實務，本研究亦進行鋼構橋梁常用塗裝系統之耐用年限評估，除加速耐候試驗與現地曝曬試驗外，並參考文獻之塗膜消耗速率以建議不同性能要求下之對應耐用年限，以做為不同塗裝系統更新週期之設定依據。本研究以某直轄市之26 座鋼構橋梁為例，主要選取 8 項橋梁構件/元件，共包括：橋面板、支承、伸縮縫、面層、防落橋裝置、主結構、欄杆及護牆、排水設施等，利用上列元件/構件估算所得維護費用，再依係數進行修正以得出橋梁整體定期維護成本，並試算不同塗裝系統及更新週期下之費用，以了解其對生命週期維護成本之影響，可做為後續維護計畫之擬定參考。
TitleLife-cycle Cost Assessment Method Development for Steel Bridges Considering the Effect of the Renewal Periods of Coating Systems
AuthorC. K. Chiu, C. C. Chen, M. Y. Chen
Keywordssteel bridge, deterioration rate, life-cycle maintenance cost, anti-corrosion coating system
AbstractIn the maintenance stage of steel bridges, the costs can be divided into the regular maintenance cost and anti-corrosion coating cost. For the regular maintenance cost, this work adopts the Bayesian updating to determine the deterioration rate of each component or member. Additionally, based on the minimal regular maintenance cost, the corresponding maintenance period can be obtained. In order to quantify the renewal cost of the anti-corrosion coating system, this work conducts the accelerated-weathering test and site exposure test for the anti-corrosion coating materials. In addition to the testing results, the past investigations on the consuming rates of the specified coating materials for steel bridges are referred to determine the renewal periods of the anti-corrosion coating system. Finally, an assessment method of the life-cycle cost (LCC) of steel bridges is developed to investigate effect of the renewal period of the anti-corrosion coating system on the LCCs for 26 steel bridges located in a special municipality in Taiwan.
標題容量位移雙反應譜－基於損傷之鋼筋混凝土橋梁耐震設計與評估法
作者王柄雄、張國鎮、歐昱辰
關鍵字反應譜、非彈性位移比、損傷指標、平滑型遲滯模型、遠域地震、近斷層地震、耐震設計與評估、鋼筋混凝土橋梁
摘要本研究提出一套容量位移反應譜(Capacity-based inelastic displacement spectra)，其係由一個非彈性位移比CR反應譜與一個相應之損傷指標DI反應譜所構成之雙反應譜(Dual spectra)，可用於鋼筋混凝土橋梁之耐震性能設計與評估。反應譜之建置係藉由一個功能強大的平滑型遲滯模型，可考慮不同橋柱設計參數之影響，並分別就遠域及近斷層地震進行單自由度系統之非線性動力歷時分析而得。本研究證實在任何的位移加載歷程下，Park and Ang 所提出之損傷指標不但可用來準確地預測橋柱的強度衰減時機，更可作為評估橋柱真實可視破壞狀態的良好指標，進而得到較佳的橋梁耐震性能評估結果。採用遠域地震所計算之CR反應譜顯示，當結構週期約略大於0.8 秒時，非彈性位移比CR可近似滿足等位移原理；但就近斷層地震而言，在全部反應譜週期範圍內則皆不滿足此原理。此外，分析結果顯示近斷層地震會較遠域地震產生明顯較大的CR及DI值，且當相對強度比R = 5.0 時，大部分本研究所考量之設計方案皆無法承受所考慮之近斷層地震的侵襲。最後，根據所計算之反應譜分析結果，本研究分別就遠域及近斷層地震各提出一套非彈性位移比CR及相應之損傷指標DI之反應譜公式，並依據所建置之容量位移反應譜，提出一套基於損傷之鋼筋混凝土橋梁耐震性能設計與評估方法。
TitleCapacity-Based Inelastic Displacement Spectra for Seismic Design and Evaluation of Reinforced Concrete Bridges
AuthorPing-Hsiung Wang, Kuo-Chun Chang, Yu-Chen Ou
Keywordsspectrum, inelastic displacement ratio, damage index, smooth hysteretic model, far-field earthquake, near-fault earthquake, seismic design and evaluation, RC bridges
AbstractCapacity-based inelastic displacement spectra that comprised an inelastic displacement (CR) spectrum and a corresponding damage state (DI) spectrum was proposed in this study to aid seismic evaluation and design of reinforced concrete (RC) bridges. Nonlinear time history analyses of SDOF systems were conducted using a versatile smooth hysteretic model that accounted for the influences of various column design parameters when subjected to far-field and near-fault ground motions. It was proved that the Park and Ang’s damage index not only can be used to accurately predict the onset of strength deterioration, but also can be a good indicator for assessing the actual visible damage condition of column regardless of its loading history, providing a better insight into the seismic performance of bridges. The computed spectra show that the CR for far-field ground motions approximately conforms to the equal displacement rule for structural period (Tn) larger than around 0.8 seconds, but that for near-fault ground motions departs from the rule in the whole spectral regions. Moreover, the near-fault ground motions would lead to significantly greater CR and DI than far-field ground motions and most of the design scenarios investigated in this research cannot survive the near-fault ground motions when relative strength ratio R = 5.0. Based on the computed spectra, CR and DI formulae are presented as a function of Tn, R, and various design parameters for far-field and near-fault ground motions. Finally, application of the proposed spectra to the performance-based seismic design and evaluation of RC bridge was presented using DI as the performance objective.
標題以極值分析理論推估最佳設計風壓係數
作者羅元隆、Michael Kasperski
關鍵字設計風速、極值分布曲線、風壓係數、最佳設計非超越機率
摘要決定設計風載重大小取決於設計風速與設計風壓係數的評估。其中設計風速的評估由實場監測長年累積的數據經極值分析理論求得，因此首先必須對於標的物的氣象資料資訊進行了解。再者，設計風壓係數由標的物的幾何外型決定，可以經由正確的物理縮尺風洞試驗，在滿足各種無因次化參數條件下，獲得標的物每個局部位置的風壓係數值。設計風速與設計風壓係數的機率密度分布函數透過乘冪計算，必須滿足對於標的物破壞的目標超越機率。本研究以台灣本土的氣象資料進行設計風速的評估，輔以一簡單的高層建築物理縮尺實驗作為設計風壓係數的推算範例，推算出滿足於標的物分類及回歸期的最佳設計風壓係數值及其相對應之最佳設計非超越機率值、最佳設計風載重。
TitleEstimation of Design Pressure Coefficient Based on Extreme Value Analysis Theory
AuthorYuan-Lung Lo, Michael Kasperski
KeywordsDesign wind speed, Extreme value distribution, Pressure coefficient, Optimal design fractile
AbstractTo determine a proper design wind load relies on correct evaluations on design wind speed and design wind pressure coefficient. The evaluation on design wind speed requires the understanding of local meteorological information accumulated for a long-term period and the knowledge of extreme value analysis; wind pressure coefficient of the target structure can be obtained via properly arranged wind tunnel test fulfilling the satisfactory demand of all non-dimensional aerodynamic parameters. By satisfying the target exceedance probability of failure of a target building, convolution process of probability densities of design wind speed and pressure coefficients is carried out and then the optimal design pressure coefficient can be found through iterative calculation. This study intends to apply local meteorological information in Taiwan and a simple wind tunnel test to demonstrate the determination of the optimal design fractile and its corresponding design wind pressure coefficient and design wind load.