Finite Element Simulation of Concrete-Filled Double-Skin Tube Columns Subjected to Postearthquake Fires

Abstract

Detailed finite-element (FE) analyses were conducted using commercial software to simulate the behavior of concrete-filled double-skin tube (CFDST) columns subjected to postearthquake fires. The main goal of these simulations was to replicate results from a series of experiments that first subjected CFDST columns to different levels of seismic damage by applying cyclic lateral loading, and then fire testing of the same specimens in a furnace. The numerical simulations paralleled the experiments in the loading sequence. Different material models and modeling techniques were assessed in terms of reproducing experimental observations including local failure modes such as steel tube buckling. Results from the cyclic loading simulations including residual deformations were maintained as initial conditions for the subsequent thermal-stress analysis to simulate the fire testing phase of the experiments. A sequentially coupled nonlinear thermalstress analysis was conducted on the models of CFDST columns to study the effects of exposure to a standard fire (time-temperature) curve. Numerical simulations using material properties adopted from European general rules for structural fire design provided a reasonable comparison to experimental results for both during and postfire situations.

Experimental and Numerical Studies of Reinforced Concrete Columns Confined by Circular Steel Tubes Exposed to Fire

“…Han and his research group conducted numerous studies on CFST structures exposed to fire using these thermal models, including circular, square and rectangular CFST columns during and after fire exposure (Han et al 2003a;2003b;2003c;2005b;Yang et al 2008;Song et al 2010a), beam to column connections (Tan et al 2012;Song et al 2010b) and frames (Han et al 2012) exposed to fire, confirming the robustness of the thermal models. The thermal models provided in Eurocode 4 have also been successfully employed for the simulation of CFST columns by many researchers (Schaumann et al 2009;Ding and Wang 2008;Espinos et al 2010;Ibañez et al 2013;Imani et al 2015;Neuenschwander et al 2017a), with good predictions obtained. These models would also be expected to be suitable for the simulation of STCRC columns exposed to fire.…”

Bending and Shear Behaviour of Waste Rubber Concrete-Filled FRP Tubes with External Flanges

“…The contact interaction between the surfaces allows them to separate under the effect of bending load at a certain frictional coefficient. A frictional coefficient of 0.25 was considered, as this value typically ranges between 0.2 and 0.3 [ 41 ]. A symmetric boundary condition was applied to the symmetry surface of the specimens under four-point bending and short beam shear where the nodes were restrained from translating in the Z-direction and rotating about the X- and Y-directions.…”

Experimental and Numerical Investigation on the Resistance and Failure Behavior of Ductile Concrete-Filled Double-Skin Tube Columns Subjected to Post-Earthquake Fires

“…Global behavior, on the other hand, was similar for all of the specimens, as the analyses resulted in global bucking of specimens after 60-65 minutes of fire exposure. Additional details on finite element simulations can be found in a study by Imani et al (2015).…”