Behavior of Concrete-Encased Composite Frame Joints Using High Strength Concrete under Cyclic Loading: Numerical Approach

Abstract

The design of a composite frame joint was characterized in a high level of seismic performance when subjected to cyclic loading. Composite structures were used for the Construction of high rise building, bridge and heavy structure to safeguard steel members from fire and corrosion, reduce the cost of construction, and enhance both resistance and stringency. Among the composite frame joint, the beam column joint plays a crucial role in determining the overall behavior of the structure. This research focus on the numerical simulation investigation of composite encased beam column interior joints under cyclic loading by finite element method. The responses of hysteresis curve, load carrying capacity and failure mode was investigated. Using developed models Parametric study have been done to investigate the effects of concrete strength, uniaxial load ratio with a constant eccentricity of e=10mm, longitudinal reinforcement ratio, and transverse reinforcement spacing were utilized to investigate the composite encased beam column joints under cyclic loading. Totally 43 specimen carried out to examine their lateral load carrying capacity, mode of failure and hysteresis behavior under cyclic load of the beam column joint. The result of load carrying capacity under cyclic load was increased by 12.36% as concrete grade increase C-60 to C-90 and increased again the load capacity increased by 14.31% as concrete grade increase to C-100 concrete grade strength. The result of load carrying capacity decrease by 1.49% when uniaxial load increase 20% to 30% and decrease by 1.63% as uniaxial load increase 20% to 40%. This indicate that the load carrying capacity of FEC beam column under cyclic loading were slightly influenced by the percentage increase of the design plastic resistance decrease the performance. Longitudinal reinforcement ratio increase from 0.0094 to 0.0283 increase load carrying capacity by 14.31% and the longitudinal reinforcement ratio from 0.0188 to 0.0283 also increased the load carrying capacity by 2.23%. The transverse reinforcement spacing increase from 40mm to 80mm space have decrease load carrying capacity by 4.65%. The stirrup has high contribution to keeps the longitudinal reinforcement from buckling and concrete from spalling. The future for further understanding works recommended on the effects of different steel shape with normal concrete strength and additional experimental study under cyclic loading