本文主要係藉實驗方法來探討鋼筋混土梁遭受火害後其力學行為的改變。

　　研究內容包括20支實尺寸鋼筋混凝土矩形梁以四种不同延燒時間，試燒其中之14支試體。以不同配筋量及載重型式來控制梁試體的破壞型態。本研究以環氧樹脂及無收縮混凝土時行火害後梁構件之修補試驗，以探討修復之可行性。

　　經試驗可獲得梁構件遭受火害時，其內部混凝土及鋼筋的溫度分佈隨時間變化的資訊。試驗結果顯示，鋼筋混凝土梁遭受火害後其抗彎、抗剪強度均有降低現象，而其抗彎勁度更有明顯之降低。試驗發現以本文採用修補方法，幾可全部恢復梁構件之原抗彎、抗剪強度。

This research is to investigate the post behaviors of reinforced concrete beams subjected to severe fire through a series of experiments.

　　Twenty beam specimens with dimension 30cm × 50cm × 340cm were tested. Sixteen of them were heated according to NBS-476 standard fire curve. Fire duration included 2.0, 2.5, 3.0 and 3.5 hours, Different steel ratio designed and different type of loading governed the failure types of beams due to flexure and due to shear.

　　In order to assess the possibility of restoring the strength of the damaged R.C. beams through proper repairing, two beams were repaired using exposy and concrete materials and then tested to examined their behaviors.

　　The thermal couples installed in the test specimens provided the information of temperature distributed in the beams exposed to fire. The test results indicated it hat the flexural strength and shear strength decreased as the fire duration incresed. It were also found that the flexural stiffnesses of the damaged beasm decreased significantly. The repairing tests showed that the flexural and shear mstrength of beams recovered quite sell by means of the proposed repairing method.

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