Browsing by Author "Chen, Cheng-Chih"

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Axial compressive behavior of square composite columns confined by multiple spirals
(2014-12-01)
Liang, Ching-Yu
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Chen, Cheng-Chih
;
Weng, Cheng-Chiang
;
Yin, Samuel Yen-Liang
;
Wang, Jui-Chen
This study elucidates experimentally and analytically the axial compressive load-carrying capacity and behavior of square composite steel and concrete columns confined by multiple interlocking spirals. The variables of the specimens included type of the lateral reinforcement (rectilinear hoops and multiple spirals), spacing of the lateral reinforcement, and shape of the structural steel section (cruciform and box-shaped). Specimens were tested under monotonically increased axial load. The test results demonstrated that the composite columns with multiple spirals achieved great axial load-carrying capacity and deformability because of the excellent concrete confinement attributed to the multiple interlocking spirals and the structural steel section. Smaller spacing of the spirals and larger area of the highly confined concrete in the composite columns resulted in the better strength and ductility of the columns. An analytical model was proposed to calculate the load-displacement relations of the specimens, and the model predicted well the behavior of the specimens. The effectiveness of the multiple interlocking spirals in the square composite columns was evident via this study. (C) 2014 Elsevier Ltd. All rights reserved.
Axial strength and ductility of square composite columns with two interlocking spirals
(2013-11-01)
Shih, Tsu-Han
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Chen, Cheng-Chih
;
Weng, Cheng-Chiang
;
Yin, Samuel Yen-Liang
;
Wang, Jui-Chen
The axial compressive capacity and load-displacement behaviour of composite columns confined by two interlocking spirals were experimentally and analytically investigated. The innovative spiral cage used for a square column was fabricated by interlocking a circular spiral and a star-shaped spiral to enhance the confinement effect for the core concrete. Eight full-scale square composite columns were tested under monotonically increased axial compression. Experimental results demonstrated that, with significant savings of the transverse reinforcement, the composite columns confined by two interlocking spirals achieved excellent axial compressive strength and ductility capacity. Moreover, an analytical model was developed to take into account the concrete confinement due to the structural steel in addition to the transverse reinforcement and distributions of the longitudinal bars. The analytical results accurately predicted the axial compressive capacity and load-displacement behaviour of the specimens. Consequently, the application of the two interlocking spirals in a square composite column appears to be very affirmative. (C) 2013 Elsevier Ltd. All rights reserved.
Fire Resistance of Concrete Slabs in Punching Shear
(2014-03-01)
Liao, Jen-Shou
;
Cheng, Fu-Ping
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Chen, Cheng-Chih
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土木工程學系
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Department of Civil Engineering
Twelve specimens of reinforced concrete slab-column connections were tested to investigate fire resistance of punching shear. Half of the specimens were tested at room temperature to determine punching shear strength. Half were tested for fire resistance. The parameters of the specimens included steel reinforcement ratio, concrete compressive strength, and fire loading type. Fire resistance tests were carried out under constant maximum service loads at elevated temperatures according to ASTM E119 time-temperature curve. Temperature distribution, time-deflection relationship, and fire resistance were measured to determine the mechanical behavior of the slab-column connections subjected to fire loading on either the tension side or the compression side of the slabs. Experimental results showed that slabs heated on the compression side did not fail for up to 8 h, whereas those heated on the tension side failed at around 4 h. Specimens using normal-strength concrete have better fire resistance than those using high-strength concrete. The normal-strength concrete specimen also showed no spalling, whereas the high-strength-concrete specimen spalled under fire loading on the compression side. (C) 2013 American Society of Civil Engineers.
Seismic performance of steel beam-to-column moment connections with tapered beam flanges
(2013-03-01)
Chen, Cheng-Chih
;
Lin, Chun-Chou
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土木工程學系
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Department of Civil Engineering
This work elucidates experimentally and numerically the behavior of steel beam-to-column moment connections proposed by widening and tapering the portion of beam flanges to increase the ductility and strength of the connection used in moment-resisting frames. Effectiveness of the tapered beam flange and the extent to which geometrical variables of the tapered beam flange affects the connection behavior were examined, based on a parametric study using finite element analysis. Additionally, seven full-scale specimens were tested to clarify their cyclic performance. All of the proposed tapered beam flange specimens, using either the column-tree full welded connection or the web-bolted flange-welded connection, achieved satisfactory ductile behavior by forming a plastic hinge in the beam section away from the column face. Extensive yielding, which occurred in the tapered zone of the beam section, resulted in stable energy dissipation. Based on the parametric study and experimental results, we recommend design parameters and a related procedure for practical design applications. (C) 2012 Elsevier Ltd. All rights reserved.
Strengthening of Reinforced Concrete Slab-Column Connections with Carbon Fiber Reinforced Polymer Laminates
(2020-01-01)
Chen, Cheng-Chih
;
Chen, Shun-Long
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土木工程學系
;
Department of Civil Engineering
This study presents the structural behavior and punching shear strength of the concrete slab-column connections strengthened with carbon fiber reinforced polymer (CFRP) laminates. The variables considered for the twelve specimens included the compressive strength of the concrete, the ratio of the tensile steel reinforcement, and the amount of the CFRP laminates. Square concrete slabs were simply supported along four edges. During the test, monotonically concentrated load was applied to the stub column located at the center of the slab. The punching shear strength, stiffness, and mode of failure were investigated. Test results demonstrated that increasing the compressive strength of concrete, ratio of the steel reinforcement, and amount of the CFRP laminates led to an increase in the punching shear strength of the slabs. Moreover, the CFRP laminates were effective in appreciably increasing the punching shear strength of the slab-column connections. An analytical approach was conducted to calculate the punching shear strength of the slab-column connections strengthened with CFRP laminates. Based on the theory of reinforced concrete members, the application of the CFRP laminates increased the flexural strength of the slab and resulted in an increase of the effective depth of the slab section. Consequently, the punching shear strength was increased. The results of the analytical calculation revealed that the analytical work accurately predicted the experimental punching shear strength.
包覆填充式箱型鋼管混凝土柱火害行為研究
(2012)
陳誠直
;
Chen, Cheng-Chih
;
國立交通大學
火災可能導致建築結構損壞或倒塌，嚴重危害人員生命安全與公共安全。柱構件為主要支撐建築物之結構構件，因此柱構件在建築防火設計有其重要性。近年來，國內高樓建築普遍採用鋼骨鋼筋混凝土構造，在工程實務上，常於鋼骨鋼筋混凝土柱構件配置剪力釘，然而設計規範因可採強度疊加觀念未要求柱構件之鋼骨配置剪力釘。由以往內灌混凝土箱型柱(Concrete Filled Box Column, CFBC)火害研究成果發現，CFBC承受軸向載重時，因不同材料性質導致強度損失及熱膨脹能力有所差異，此差異現象可能會影響CFBC構件耐火能力。除軸向載重外，剪力釘於柱構件耐火性能與破壞模式將扮演重要角色。此方面研究甚為缺乏，因此，本研究將以實驗方法與分析方法探討設計參數於CFBC耐火性能的影響。預期目標： 1. 利用承重與高溫實驗結果建立箱型鋼管混凝土柱設計參數於耐火能力之影響。 2. 利用分析方法模擬實驗行為並與試驗結果驗證，建立箱型鋼管混凝土柱設計參數之耐火能力之模型。 3. 鋼骨鋼筋混凝土結構設計規範耐火性能設計專章單一構件部分具體條文研訂。 4. 以結構耐火的角度量化設計規範中剪力釘配置與數量，並據以修訂「鋼骨鋼筋混凝土構造設計規範與解說」中相關設計內容並加以解說。 5. 針對建築技術規則建築設計施工編防火構造中，包覆型(鋼骨在外)混凝土柱之防火時效進行實質驗證，提供營建署修訂相關條文時之參考。 6. 提供工程實務上應用，可供鋼骨鋼筋混凝土結構火害後承載能力之評估
鋼骨鋼筋混凝土高溫材料性質之研究
(2011)
陳誠直
;
Chen, Cheng-Chih
;
國立交通大學
火災閃燃發生後，現場溫度約高於600°C，此時梁柱構件因高溫而導致強度與勁度折減，此時複合構件承載能力倘無法承受外加荷重，可能造成建築整體或局部崩塌，至救災人員受困或無法搶救傷者，可知溫度分布對材料本身力學性質因高溫而造成的殺傷力。因SRC斷面熱傳速率直接影響後續之結構火害中之行為，於不同火害加熱面下（如二面受熱-角邊梁柱、三面受熱-邊梁與邊柱等），其溫度場之分佈差異，易造成不對稱之結構變形，更甚者提早產生破壞。因此，規劃進行高溫所造成材料性質變化，包含材料之熱傳導特性、比熱、高溫應力應變行為等有其必要性。本研究預期成果如下：一、配合現行國內建築技術規則與規範常用之SRC構造，發展SRC構件火害過程中斷面熱傳評估模式。二、鋼骨鋼筋混凝土材料耐火性規範與檢測基準建立，包含下列量化指標: (a) 材料高溫特性（熱傳導係數、比熱）與鋼高溫材料應力與應變曲線 (b) SRC火害結構設計材料性質(鋼材、混凝土與鋼筋)3種以上之試驗標準草案。三、建立本土化SRC建築結構材料之火害性質四、建構常用構造火害行為模式，進而研修適合國內現行法規採用之規範或標準，以供性能化法規與設計需求，作為研發結構火害後修復技術之參考。預期效益：提高SRC建築物防火安全要求與性能防火設計驗證基準本土化。