Experimental study on fire performance of axially-restrained NSC and HSC columns

Thermal-induced restraint forces in reinforced concrete columns subjected to eccentric loads

“…(13) and (14), α θ e developed in the tests of C1-3-25, C1-5-60, and C2-1-25 can be determined as shown in Fig. 12.…”

“…This so-called thermal-induced restraint force may result in a significant increase in the total axial force [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18], as well as the additional bending moments acting on the column and thus, associated with deteriorations of material strength and stiffness at elevated temperatures, may lead to a premature failure of the column. Therefore, a proper prediction of the development of restraint force is critical in the fire resistance analysis of compression members in framed buildings.…”

“…There have been a considerable number of published studies on axially-loaded and restrained steel and composite columns ( [1][2][3][4][5][6][7][8]), and on restrained reinforced concrete (RC) columns [9][10][11][12][13][14][15][16][17][18] subjected to fire. Based on early fire tests conducted on two axiallyloaded and fully-restrained RC columns [9], a simplified equation to evaluate the magnitudes of restraint forces was proposed [10].…”

“…A number of experimental studies on full-scale specimens [13,14] were conducted on axially-restrained RC columns under concentric loads and axial loads with either unixial or equal biaxial eccentricities, but no analytical model has been introduced. The differences between the case of a heated column acting as a single element or being part of a frame is discussed numerically [15].…”

Numerical analysis of lateral displacement of beam-column joints in concrete frame structures subjected to fire

“…Through sequential tests of axially restrained high-strength concrete columns in fire, it was found that the restrained columns' fire behavior decreases with the increasing of the load ratio (Benmarce and Guenfoud, 2005). Experimental study on fire performance of axially restrained normal-strength concrete and high-strength concrete columns was conducted by Wu and Li (2009), and the axial restraint was effective when the column was expanding as well as contracting. It was shown that the axial restraint ratio has a positive impact on the development of the column axial deformation during the contraction phase beyond the initial equilibrium state, and the development of the column axial force during the contracting and cooling phases follows nearly parallel trend for the columns with the same load ratio.…”