摘要

目前鋼筋混凝土仍為建築材料之主體，由於火災是建築物損害的一大因素，因此鋼筋混凝土結構物受火害的相關研究相當的重要。本研究之目的在探討梁柱接頭於高溫中、後之溫度變化及變形。
本研究以一棟七層樓的建築物為討論對象，取其外柱部分的梁柱複合構件設計實尺寸試體，使用普通混凝土(NC)及自充填混凝土(SCC)兩種材料，測試工作主要分為高溫中、冷卻過程以及殘餘強度三階段，本研究並利用ANSYS套裝軟體建立電腦模型，以與實驗值相互印證。
主要研究成果如下：
1. SCC3試體爆裂的範圍比NC3試體廣，主要爆裂發生在梁柱接頭處的背面，深度約可達約20mm-40mm，可見部分箍筋裸露。
2. NC3試體經過104分鐘的高溫作用，梁柱接頭內部中心處溫度約為80℃，梁柱接頭背部溫度高約600℃。SCC3試體經過180分鐘的高溫作用，梁柱接頭內部溫度較NC3試體高100℃，接頭背部約高150℃，靠近邊梁以及長梁處最高有600℃的溫差。
3. NC3試體梁柱接頭內部頂層撓曲鋼筋所受溫度最高約為100℃，底層撓曲鋼筋最高溫度約達250℃至310℃。
4. ANSYS模擬的溫度分佈與實驗值很接近，證明本文採用的熱學參數應屬合理。
5. 殘餘強度測試中，NC3試體及SCC3試體的梁柱接頭因受梁載重的影響，轉動方向皆為順時針方向。NC3試體的接頭在柱載重為3920kN時有最大轉動角，約為0.48度，SCC3試體在柱載重為3500kN時有最大轉動角，約為0.39度。

Abstract

At present, reinforced concrete is still a main body of the building materials, and fire is a major factor which causes building damaged. Therefore, the related research of the reinforced concrete structures under fire is an important issue. It is the objective of this study to investigate the behavior of beam-column joint under elevated temperature test.

This research takes the exterior beam-column sub-assemblage of a seven-floor reinforced concrete building to discuss. We used two kinds of materials, one was ordinary concrete (NC) and the other was self-compacting concrete (SCC). There were three stages in the tests, i.e., elevated temperature, cooling, and residual strength stages. We also used ANSYS program to build up computer model and to compare with tests.

The primary findings according to this study are as follows：

1. The spalling of concrete in SCC3 specimen was severer than that in NC3 specimen. The spallings of both specimens occurred at the back of joint. The depth of damage was about 20-40mm and the stirrups were partially exposed.
2. NC3 specimen was exposed to fire 104 minutes, the center temperature of joint was about 80℃, while the back of joint was about 600℃. SCC3 specimen was exposed to fire 180 minutes, its center temperature was 100℃ higher than NC3, while the back temperature of joint was about 150℃higher, the maximum difference of temperature near the longitudinal beam and spandrel beam was about 600℃.
3. The temperature of top flexure reinforcement in joint of NC3 specimen was about 100 ℃, while that of bottom flexure reinforcement was about 250℃-310℃.
4. The temperature distribution predicted using ANSYS program was very close to tests, therefore, the assumed thermal parameters were reasonable.
5. In the residual strength test, the rotation of joints’ in NC3 and SCC3 specimens were clockwise due to beam load. The highest rotation of NC3 specimen was 0.48 degrees when column load was 3920 kN, while that of SCC3 specimen was about 0.39 degrees when the column load was 3500kN.

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