Fire resistance of concrete encased steel columns under 3- and 4-side standard heating

Results from seven fire resistance experiments on concrete encased steel (CES) columns under standard fire exposure conditions are presented. The test parameters include column size, 3- and 4-side fire exposure, load intensity and load eccentricity. Data from the tests is utilized to study the effect of the aforementioned parameters on thermal and structural response of concrete encased steel columns. Test results show that CES columns have higher fire resistance under 3-side heating than that under 4-side heating. Also, load ratio and load eccentricity have a noticeable influence on the fire resistance of CES columns. In addition, spalling of the concrete decreases the fire resistance of CES columns. A comparison of measured fire resistance of CES columns with those predicted using current code provisions indicate that the current provisions may not be conservative in some situations.