第三十五卷第四期 (期別138) (109年)

第三十五卷第四期 (期別138) (109年)

第十五屆結構工程暨第五屆地震工程研討會特刊(上集)

客座主編:周中哲、廖文義、洪崇展

標題以熔射覆膜技術提升摩阻型螺栓接合之滑移係數
作者陳誠直、謝宗成、張誠、李思維
關鍵字摩阻型接合、熔射覆膜、滑移係數
摘要摩阻型螺栓接合之設計理念為利用高強度螺栓鎖緊時,螺栓之預拉力將於接合鋼板上產生夾緊力,此夾緊力將進一步產生鋼板間的摩阻力。因此摩阻型接合將可提供螺栓剪力方向的抗剪強度,此抗剪強度與螺栓的夾緊力與鋼板間的滑移係數有關。本研究目的在探討以熔射覆膜技術於鋼板摩擦面上覆膜,提升摩阻型螺栓接合的滑移係數。實驗計畫設計試體以探討熔射覆膜材料(純鋁、鋁鎂合金)、覆膜厚度(150、300與450 µm)及鋼板鏽蝕對滑移係數之影響。實驗結果顯示,鋼板接合面之鏽蝕可提升滑移係數。於些微鏽蝕情況下,鋼板接合面僅噴砂未覆膜之平均滑移係數為0.74,純鋁覆膜之平均滑移係數為0.88,鋁鎂覆膜之平均滑移係數亦為0.88,皆高於設計規範中鋼板去除黑皮未塗裝表面之滑移係數0.33。熔射覆膜材料與覆膜厚度於滑移係數無顯著影響,但於鏽蝕情況下隨著覆膜厚度的增加會造成滑移發生後螺栓預力損失的提高。於鋼板接合面施以熔射覆膜鋁或鋁鎂合金,可提升摩阻型螺栓接合之滑移係數,增加摩阻型接合強度,達到減少接合尺寸及螺栓數量。
TitleIncreasing slip coefficient of bolted slip-critical joints using thermal sprayed coating technique
AuthorCheng-Chih Chen, Tsung-Cheng Hsieh, Cheng Chang, Sui-Wei Lee
KeywordsSlip-critical joint; thermal sprayed coating; slip coefficient
AbstractThe design philosophy of slip-critical joints is to utilize the friction force developed through the clamping force exerted by the pretension of the high-strength bolt. Thus, the slip-critical joint can have resistance in the direction of the bolt shear. This resistance is affected by the bolt clamping force and slip coefficient on the faying surface. The objective of this study is to increase the slip coefficient of bolted slip-critical joints by applying a thermal sprayed coating on faying surface. The specimens were designed to explore the effects of the coating material (aluminum or aluminum-magnesium alloy), coating thickness (150, 300 and 450 µm), and corrosion on the steel plate on the slip coefficient. The test results showed that exist of the rust increased the slip coefficient. In the case of slight corrosion, the blasted-cleaned faying surface resulted in an average slip coefficient of 0.74. The average slip coefficient was 0.88 for either the aluminum or aluminum-magnesium coatings. These slip coefficients are higher than the slip coefficient of 0.33 for unpainted clean mill scale specified in the design code. The coating material and thickness had insignificant effect on the slip coefficient. However, in the case of corrosion, the bolt pretension loss at slip was increased when the coating thickness was increased. The thermal sprayed coating of either aluminum or aluminum-magnesium on the faying surface can enhance the slip coefficient, increase the resistance of the slip-critical joint, and result in a smaller joint size and less high-strength bolts.
標題鋼筋混凝土梁滑移剪力設計之研究
作者王勇智、郭育廷
關鍵字New RC梁、塑性鉸區、塑鉸外移設計、滑移剪力破壞、斜向鋼筋
摘要本研究繼先前研究New RC梁設計,乃利用T擴頭鋼筋進行塑鉸外移設計時,雖有成功產生塑性鉸轉移,但卻有明顯垂直於梁向之滑移剪力裂紋發生;而塑性鉸區發生在傳統柱面時、或預鑄RC梁冷接縫在塑性鉸區時,亦有可能有類似滑移剪力裂紋破壞,因此引發本研究主題產生。故本研究主要目的是探討一般RC梁構件受震中,對於可能有潛在滑移剪力(sliding shear)破壞RC梁,如何檢查以及設計梁斜向鋼筋,以利抑制垂直剪力滑移破壞產生。
本文主要先收集先前計畫New RC梁與相關文獻一般RC梁之耐震測試數據,以統計方法檢核紐西蘭規範NZS 3101-2006判斷梁塑鉸區可能發生滑移剪力破壞規定之正確性。其結果為,建議以斷面剪應力0.25ඥf ୡᇱ(MPa)作為滑移剪力破壞之判別,且較適用於長跨梁(a/d≧2.5)。再者,對於梁構件塑性鉸區有潛在垂直滑移剪力裂縫產生時,則應考慮增設梁斜向鋼筋於塑性鉸區域,以利有效抑制此滑移剪力裂紋產生。本文亦參考其規範在斜向筋設計規定,以實驗作印證;結果為有加入斜向鋼筋RC梁,除了可以抑制垂直梁向滑移剪力裂縫發生外,亦可增進構材耐震性能。最後,綜合紐西蘭規定及本研究結果,乃建議一般跨度RC梁是否要設計斜向鋼筋之設計流程,以供參考。
TitleStudy on the sliding shear design for reinforced concrete beams
AuthorYung-Chih Wang, Yu-Ting Kuo
KeywordsNew RC, plastic hinge, hinge relocation design, sliding shear, diagonal reinforcement.
AbstractThis study follow up the previous research on the hinge relocation design by using T-headed bars. The main conclusion is that the T-headed bars as extra reinforcement can successfully relocate the plastic hinge zone from the column face to a distance away from the face, however the final failure mode of sliding shear occurred. The similar sliding shear failure could be also found in the plastic hinge zone occurred at the traditional column face, or in the precast cold connection located in the plastic zone. Therefore, the main purpose of this study is to discuss how to design the diagonal reinforcement of the beam to prevent the occurrence of vertical sliding shear cracks for the general RC beam members subjected to the major earthquake.
This article mainly collected the tested beams subjected seismic loading to verify the design of the sliding shear specified in the NZS 3101-2006. It was concluded that the sectional shear stress , 0.25ඥf ୡᇱ(MPa), to check the potential sliding shear failure occurred in the plastic zone of RC beams is suitable for normal-span beams (a/d≧2.5). Therefore, if the potential vertical sliding shear cracks may be occurred in the plastic hinge zone of RC beams, the diagonal reinforcement shall be considered. Meanwhile, the cyclic testing performed comparing two types of beams between with and without diagonal bars repealed that the RC beams with diagonal bars can prevent the sliding shear cracks from occurring, and improve their seismic resistance. The design flow chart for prevention of sliding shear failure occurred in RC beams is finally suggested in the paper.
標題幾何初始缺陷對具深寬翼鋼柱之抗彎矩鋼構架其耐震崩塌性能之影響
作者張廷浩、吳東瑜
關鍵字初始缺陷、鋼結構、抗彎矩構架、地震工程、崩塌性能
摘要熱軋型鋼由於軋制、運輸及安裝過程等影響,必定會存在初始變形,然而,幾何初始缺陷對特殊抗彎矩構架崩塌性能之影響,卻仍無詳細之研究或探討。因此,本研究以有限元素模擬,探討初始幾何缺陷對具深寬翼鋼柱之四層樓及八層樓之特殊抗彎矩構架其耐震崩塌性能之影響。模擬結果顯示,不同初始幾何缺陷的施加可改變鋼柱之挫曲行為,但對抗彎矩構架崩塌行為之效應於不同地震歷時下並無一致性。對於四層樓且軸力小之構架,初始幾何缺陷因構架在不同地震歷時下之崩塌模式不同,對崩塌性能之影響較不顯著;對於八層樓構架與軸力大之四層樓構架,因鋼柱挫曲於不同地震歷時下之行為較一致,因此初始幾何缺陷對構架崩塌性能影響較為明顯。然而平均而言,以挫曲模態疊加法所建立之初始缺陷,因其對崩塌性能之影響不大且可能會帶來正面影響,加上使用高擬真及高精度之有限元素模擬時,構件在加載初期即可生成初始缺陷,故建議以高精度之模擬探討構架於地震歷時下之崩塌行為時,可忽略初始幾何缺陷之效應。
TitleEffect of geometric initial imperfections on seismic collapse capacity of steel special moment frames with deep columns
AuthorTing-Hao Chang ,Tung-Yu Wu
KeywordsGeometric initial imperfections; steel special moment frames; seismic collapse capacity
AbstractAlthough wide-flange (W-shape) steel members are known to have initial geometric imperfections (IGIs) due to fabrication and installation, the effect of IGIs on seismic behavior of steel special moment frames (SMFs) is still not well understood. To address this shortcoming, seismic collapse capacity of 4-story and 8-story prototype SMFs with various types of IGIs is computationally evaluated to quantify the effect of IGIs created by combining buckling shapes. The results show that even though IGIs can affect column buckling behavior and frame collapse mode under certain conditions, their effect on seismic collapse capacity is generally small and inconsistent. Their influence also greatly depends on the directions of applied IGIs and column buckling shapes and may be positive if the directions are misaligned. As a result, it is suggested that initial geometric imperfections need not be incorporated in high fidelity numerical models with high precision, which can generate their own IGIs when loaded.
標題箱型鋼柱於不同寬厚比軸力及近斷層地震下的耐震行為與背骨曲線發展
作者周中哲、陳冠維、林德宏
關鍵字高強度銲接箱型鋼柱側向耐震實驗、高軸力柱構件、近斷層載重、背骨曲線
摘要本研究藉由分析7層樓挫屈束制斜撐構架受遠域及近斷層地震之反應,發展一樓鋼柱的遠域及近斷層側向載重位移歷時,並以實驗方式探討高強度銲接箱型鋼柱受遠域及近斷層載重作用下之耐震行為。自國內外地震中選取11組近斷層和11組遠域地震歷時紀錄,調整至最大考量地震(MCE)等級進行非線性歷時分析,發展一樓鋼柱受近斷層地震之側向載重歷時,含有自-2%到4%側位移角的位移脈衝,及2.5%的殘餘側位移角,藉此探討臺灣高強度鋼柱於中、高軸力下之耐震行為。試驗參數包括柱寬厚比、軸力比及近斷層載重歷時,共規劃6組使用SM570MC鋼材製造之全尺寸銲接箱型鋼柱試體,寬厚比介於11~21。試驗顯示寬厚比較小之銲接箱型鋼柱可有效減緩鋼板局部挫屈;美國AISC 341 (2016)之高韌性構件寬厚比限制為12.9(以標稱降伏強度Fyn=420 MPa及材料超強因子係數Ry=1.2為例),而臺灣鋼結構極限設計規範(2010)對全滲透銲接箱型鋼柱之寬厚比放寬至21,兩者差異極大,較寬鬆的鋼柱寬厚比無法確保在承擔中高軸壓力下的鋼柱在大位移下(側位移角>3%)的耐震行為,在高耐震區使用銲接箱型鋼柱承擔中高軸壓力(25~40%Py),建議應採用美國AISC 341 (2016)之高韌性柱構件進行設計。本研究並藉由搜集以往的實驗資料發展鋼柱的側向位移背骨曲線,預測鋼柱的側力與側位移行為,大幅改善ASCE 41(2013)及NIST(2017)對箱型鋼柱背骨曲線預測在高軸力下過度保守及低軸力下不保守的情形。
TitleSeismic Performance and Backbone Curve Development of Steel Box Columns Considering Compactness Ratios, Axial Loads and Near-Fault Motions
AuthorChung-Che Chou, Guan-Wei Chen, Te-Hung Lin
KeywordsSteel built-up box column, High axial compression force, Lateralcyclic test, Cyclic backbone curve
AbstractThis paper presents the seismic evaluation of high-strength steel columns in a seven-story buckling-restrained braced frame under two sets of 11 far-field motions and 11 near-fault motions, representative of maximum considered earthquake (MCE) level. The proposed near-fault displacement protocol contains a large displacement pulse from -2% to +4% drift with several small displacement cycles and a residual drift of 2.5%.The AISC 341 (2016) has a more stringent width-to-thickness (b/t) limit for highly ductile hollow box columns (HBCs) than the AIJ (2010) or Taiwan Code (2010), resulting in significant thickness difference in design. For example, the b/t limits for a highly ductile box column member with a nominal yield strength, Fyn=420 MPa, and an over-strength factor, Ry=1.2, are 12.9 and 21 based on AISC 341 (2016) and Taiwan Code (2010), respectively.Moreover, the cyclic backbone curves based on ASCE 41 (2013) and NIST (2017) underestimate the post-buckling flexural strength of HBCs, particularlyin high axial compression force.The authors conducted cyclic tests of six full-scale, built-up HBCs using SM 570M steel with the actual yield strength of 460-530 MPa using standard and proposed loading protocols.The gathered test data, supported by more test data in this work, are analyzed by a multiple regression method to obtain empirical formulations for the backbone curves of box columns that can predict the maximum column moment, plastic rotation and post-yield hardening stiffness. The proposed formulation reasonably predicts the first-cycle envelope curves of built-up HBCs, significantly improving prediction results based on both ASCE 41 (2013) and NIST (2017).
標題TMD於離岸風機結構減震之理論與振動台試驗研究
作者林錦隆、盧煉元、雷凱婷、 劉光晏
關鍵字離岸風機、調諧質量阻尼器、套筒結構、振動台試驗、減震技術、簡化模型
摘要風能兼具環保性及永續性,因此台灣近年於台灣海峽上建造風力發電機,實施海上風電場之計畫。但是台灣位處地震帶,為確保海上風力發電機的安全性及可靠性,避免風機結構或內部設備在受波浪、風及地震作用時,因振動量過大產生不穩定甚至損壞的情形發生,因此本文擬以理論與實驗方法探討調諧質量阻尼器(tuned mass damper, TMD)作為離岸風機結構減震元件之可行性。TMD為一種廣泛應用於高聳結構之有效減震技術。與其他減震裝置相比,TMD系統可整合為風機結構的一部份,因此對結構系統的影響較少。本文乃參考美國再生能源研究中心(NREL)所訂定之5-MW套筒式風機結構標準規格,製作1/25比例之套筒式風機縮尺模型及其TMD,以進行振動台測試。同時,為方便理論分析之用,本文乃針對套筒式風機支撐結構建議一簡化之分析模型,並推導其連體運動方程式,期以理論分析與實驗觀察,了解TMD於離岸風機之真實減震效益。本文透過縮尺風機支撐結構模型之振動台試驗,驗證所建議理論分析模型的正確性。同時,藉由比較裝設與未裝設TMD之風機結構振動台試驗結果,探討TMD對於套筒式風機支撐結構各自由度之減震效益。
TitleTheoretical and experimental study on vibration mitigation of off-shore wind-turbine using TMD
AuthorGing-Long Lin, Lyan-Ywan Lu, Kai-Ting Lei, Kuang-Yen Liu
Keywordsoffshore wind turbine, tuned mass damper, jacket-type structure, shaking table test, supporting structure, seismic vibration reduction, simplified model.
AbstractWind energy is clean and sustainable. Taiwan is establishing offshore wind farms using wind turbines in the Taiwan Strait. Since Taiwan is located in an earthquake active zone, in order to ensure the safety and reliability of offshore wind turbines under waves, wind and earthquakes, this study aims to investigate the suitability of using a tuned mass damper (TMD) to reduce the vibration of offshore wind turbine supporting structures. The TMD can be integrated as a part of the wind turbine structure, so it has less influence on the supporting structure of a wind turbine. In this study, based on the specifications of a 5-MW jacket-type offshore wind turbine suggested by the National Renewable Energy Research Center (NREL, USA), a 1/25 scaled-down test model and its corresponding TMD were fabricated and tested by a shaking table. Additionally, for numerical simulation, a simplified theoretical model for a jacket-type offshore wind turbine structure is proposed and its equation of motion was derived in this study. The proposed theoretical model was verified both in time domain and frequency domain using the result of the shaking table test. The experimental seismic responses of the offshore wind turbine model before and after the installation of TMD were compared, and the control performance of the TMD system for vibration mitigation of the wind turbine structure was evaluated in this study.
標題無預力且部分無握裹鋼絞線橋柱之耐震行為
作者歐昱辰、吳振維、Ade Yuniati Pratiwi
關鍵字橋柱、近斷層地震、殘餘變位、自復位、後降伏勁度、保護層
摘要近斷層地震所產生的脈衝型震動,容易造成傳統鋼筋混凝土橋柱於震後產生較大的殘餘變位,嚴重危害橋梁安全性與震後服務性。本研究開發先進自復位橋柱,利用高強度鋼絞線作為橋柱之彈性元件,使其於傳統竹節縱向鋼筋降伏後仍保持彈性,可降低橋梁在近斷層地震後常見之大殘餘變位。本研究完成了四座單曲率柱反覆載重試驗,包含一座對照組試體與三座先進自復位橋柱試體,試驗參數為鋼絞線的使用與不同的保護層厚度。
根據試驗所得到的後降伏勁度比α及真實保護層厚度C c,A ,利用線性回歸建立了橋柱深度保護層厚度比與後降伏勁度比之線性回歸公式,並發現於同一試體中,受壓側之保護層厚度越低者,具有越高的後降伏勁度k2 及後降伏勁度比α。橋柱後降伏勁度之維持,於拉力區使用不降伏的鋼絞線固然重要,壓力區強度的維持也是關鍵因素。由於拉力區鋼絞線維持彈性,因此在橋柱傳統縱向鋼筋降伏後,拉力區之拉力仍然持續顯示上升,為維持斷面力平衡,斷面壓力區之壓力得隨之升高,試驗結果顯示,前述升高的壓力易造成壓力區保護層混凝土較早壓碎,而壓力區的損失會造成斷面為維持力平衡,使得拉壓合力距離縮短,若保護層因施工誤差導致過厚,則會造成斷面彎矩無法再顯著提高,使後降伏勁度之維持不如設計預期。
TitleSeismic Behavior of Bridge Columns with Partially Unbonded and Non-prestressed Steel Strands
AuthorYu-Chen Ou, Jhen-Wei Wu, Ade Yuniati Pratiwi
KeywordsColumns, near-fault ground motions, residual displacement, self-centering, post-yielding stiffness, cover concrete
AbstractThe impulse vibrations generated by near-fault earthquakes are likely to cause large residual displacements of RC bridge columns after the earthquake, which seriously endangers the safety and the serviceability of the bridge. A new type self-centering bridge column is developed in this research. The new column uses high-strength steel strands as the elastic element, which can reduce the large residual displacement of the bridge after the near-fault ground motions. In this study, four large-scale columns were tested using single-curvature cyclic loading, including a conventional column and three new self-centering bridge columns. The test parameters were the use of steel strands and different cover concrete thicknesses.
According to the post-yielding stiffness ratio and the actual thickness of the cover concrete from the test results, a linear regression formula for the ratio between the depth of the column to the thickness of the cover concrete and the post-yielding stiffness ratio was established. For the same specimen, the lower the thickness of the cover concrete on the compression side, the higher the post-yielding stiffness. The use of steel strands in the tension zone is important to maintain the post-yield stiffness of the bridge column. The maintenance of the strength in the compression zone is also an important factor. Because the steel strands in the tension zone remain elastic, the tension in the tension zone continues to increase after the conventional longitudinal steel bars yield. Due to force equilibrium of the section, the compression force has to increase accordingly. Test results show that the aforementioned increased compression force is likely to cause early crushing of the cover concrete of the compressive zone, which leads to the loss of the compressive zone and decrease the distance between the tension and compression resultant forces of the section. The test results of CSC3 show that when the ratio between the depth of the bridge column to the thickness of the cover concrete is 30, the average post-yield stiffness ratio can reach 5.7%.