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碩士論文公告區 |
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| 年度： | 96 | |
| 姓名： | 許哲禎(Che-Chen Hsu) | |
| 論文題目(中)： | 鋼筋裸露混凝土結構受火害後握裹強度之初步研究 | |
| 論文題目(英)： | Preliminary Study on Post-fire Bonding Strength of Concrete Structure with Exposing Rebars | |
| 摘要(中)： | ||
| 本研究目的在於探討；如何有效評估鋼筋混凝土結構於火場中，其鋼筋以及模板附件之殘留金屬，造成顯著溫度傳入鋼筋混凝土結構內部時，對混凝土以及鋼筋之握裹強度所造成之損傷。本研究以ANSYS有限元素分析軟體進行熱傳之模擬，藉由了解結構體內部各位置之溫度傳遞情形，並利用鋼筋局部握裹應力與滑移關係之經驗公式，推估出火害後鋼筋握裹強度之損失。本研究之熱傳分析為理想條件下之結果，其所建立之模型為鋼筋裸露以及保護層厚度在1.5、4、6公分時，受高溫於400及700℃之熱傳情形。由分析結果可知，當混凝土中具鋼筋且鋼筋呈現裸露之情況時，於表面下深度4公分之熱傳溫度較之於純混凝土之結果高出23%以上，且高溫加熱500秒時之溫度比約為2.85倍。而當保護層厚度1.5公分時，混凝土已可隔絕50%熱傳溫度，在保護層厚度達6公分時，可隔絕之溫度高達到80%之多。本研究為了驗證數值模擬結果之可行性，以鋼筋裸露之試體進行高溫延燒實驗，由結果比較得知，當實驗配置過程中之界面情況可適當模擬時，ANSYS模型有能力相當精確模擬出實際之加熱過程溫度變化趨勢。 | ||
| 摘要(英)： | ||
| This research is aimed to propose an effective scheme in assessing post-fire reinforced concrete structures of which the reinforcing bars and residual metals may conduct temperature gradients into the interior of the reinforced concrete structure. Such scenario would cause damages to the concrete and bonding strength as well. The study was carried out first by simulating thermal conductivity within reinforced concrete structures using the well known computer program, ANSYS, and to find out heat transmission into the interior of structure. An experimental formula regarding bond strength after fire exposing was used to predict the residual bond strength of certain rebar layouts. Based on the simulation of the reinforced concrete using various ideal models with concrete covers of 1.5, 4 and 6 cm subjected to heating temperatures of 400 and 700 ℃, the results indicate that the exposed-to-fire condition leads to significantly higher interior temperatures while the concrete covers serve as very good isolators to temperature even with mild thicknesses. The increasing of temperature with respect to non-exposed cases can be as high as 23% at depth of 4 cm, the steady state temperature for exposed cases would become 2.85 times as high as that of pure concrete, etc. The feasibility of using ANSYS to predict thermo-transmission for reinforced concrete specimens were also evaluated with experimental data, it was found that such ANSYS models can be accurately applied to simulate related heating process as long as reasonable boundary temperatures were designated as known boundaries. |
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| 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-0828108-125041 | |