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碩士論文公告區 |
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| 年度： | 94 | |
| 姓名： | 詹千儀(Chian-Yi Jan) | |
| 論文題目(中)： | 以敲擊回音法評估火害後鋼筋握裹狀況 | |
| 論文題目(英)： | Assessment of the Fire Damage to the Bond Strength of Concrete Structures Using the Impact-Echo Method | |
| 摘要(中)： | ||
| 本研究的目的在研發可實際應用於火場鋼筋握裹力評估之非破壞檢測方法，以提供評估火害後剩餘承載力及決定修補方針之參考。本研究採用拉拔試驗試體以討論高溫延燒後鋼筋局部握裹力的損失與非破壞檢測參數間的關係。試體火害溫度控制為300、400、500、600及800℃，試體鋼筋保護層厚度在3、4、6及8cm。敲擊回音檢測方面，試驗結果包括火害後敲擊回音轉換函數中鋼筋平均振幅、鋼筋握裹強度、混凝土波速及鑽心抗壓強度之變化、拉拔試驗時敲擊回音頻譜轉換函數鋼筋平均振幅與鋼筋滑移量之關係。分析結果可知在保護層較小的3cm及4cm試體握裹強度趨勢與混凝土強度趨勢較為類似，鋼筋振幅亦即黏結程度也就是鋼筋振幅的影響不顯著；而對於保護層較大的6cm及8cm試體，在300℃及400℃時握裹強度較常溫還大20%及10%，鋼筋振幅在300℃火害溫度下振幅較公式值大30%，可推論握裹狀況比正常還要緊密。拉拔試驗時敲擊回音頻譜轉換函數鋼筋平均振幅與鋼筋滑移量之關係方面，保護層3和4cm試體之頻譜轉換函數反應結果，當鋼筋位移量為0.5mm時，各個溫度之鋼筋轉換振幅值變大，推測可能是由於剛開始進行拉拔試驗時造成鋼筋握裹介面更緊密之故。當鋼筋滑移量超過最大握裹應力之滑移量時，鋼筋轉換振幅不穩定，因為裂縫太多易造成誤判。 | ||
| 摘要(英)： | ||
| The study is aimed to evaluating the bond strength of reinforcement surrounded by fire damaged concrete using non-destructive method. The impact-echo method is applied for the task. The relationships between the local bond strength obtained by pull-out test and the parameters of non-destructive evaluation are discussed. The oven temperatures were controlled as 300,400,500,600 and 800℃. The specimens different steel cover thinkness are 30,40,60 and 80mm. For the impact-echo method, the distribution of the average steel-amplitude identified by the simulated transfer function of impact-echo response, the pull-out strength, the coring compressive strength, as well as the P-wave speed of concrete with respect to the temperature of the oven were discussed. It was found for smaller cover thickness, 30 mm and 40 mm, the bond strength is more closely related to the concrete compressive strength. The affection of reducing steel-amplitude, which means poor interfacial bonding, is limited. For larger cover thickness, 60 mm and 80 mm, the bond strengths are 20% and 10% higher than the one in room temperature when they placed in oven with constant temperature 300 and 400℃, respectively. It was found the steel-amplitude is also 30% higher than predicted for 300℃ specimens with both cover thicknesses, which implies a closer bonding at steel-concrete interfaces. When the bond slip displacement of reinforcing bar is about 0.5mm, the steel-amplitude becomes large for the specimens with cover thickness 30 and 40mm. The behavior may be caused by the reinforcing bar closery contact with the surrounding concrete at early stage of pull-out test. The variation of steel-amplitude becomes very large for the cases with bond slip over the one corresponding to the maximum bonding stress. It may due to large amount of cracks developed around the rebar. | ||
| 檔案： | 沒有相關檔案 | |
| 相關連結： | http://ethesys.lib.cyut.edu.tw/ETD-db/ETD-search-c/view_etd?URN=etd-0816106-062109 | |