A Parametric Study of Fire-Damaged Reinforced Concrete Columns under Lateral Loads

This study simulated two columns using the finite element software SAFIR. The first was a steel profile column and the second was a steel profile partially encased in a concrete column (SPPEC). Both columns were heated on four sides for one hour using the ISO834 standard fire curve. Two boundary conditions were considered for both columns, simply and doubly supported and loaded utilizing eccentric loading. A parametric analysis aimed to identify a thermal analysis of unprotected and protected steel columns in terms of temperature field distribution, and time-temperature curves of a few selected nodes were drawn from the SAFIR software. A thermomechanical study was also carried out using the results of the thermal analysis to determine the influence of slenderness on the resistance of the steel and the partially encased profile in concrete columns under fire solicitation. Finally, a comparison of the fire resistance of the two columns was made. The results proved that the slenderness negatively influences the fire resistance of the steel and composite columns and that the behavior of the composite columns is significantly better than the steel ones.

Section: Introductionmentioning

confidence: 99%

The Influence of Slenderness in Steel and Composite Columns under Fire Conditions

Farid

Boufarh²,

Maghaghi³

2023

“…Authors in [12] utilized numerical analysis using the parametric fire model of Eurocode-1 to estimate the post-fire axial and lateral performance of reinforced concrete columns. Their study included two main steps.…”

Section: Introductionmentioning

confidence: 99%

Residual Strength and Crack Propagation of Reinforced Concrete Columns under High Temperatures

Faraj,

Almaliki

2023

In the present study, reinforced concrete columns with dimensions of 200×200×1200 mm were tested under static loading and high temperatures. In the experimental work, square cross-section columns with compressive strength of 28 MPa were tested up to failure. Mechanical properties such as compressive strength, were examined under static load and then under temperatures such as 500 and 800 °C. Column specimens with the same geometry and with concrete covers of 10 and 17 mm were also put under test. Mode of failure, ductility, stiffness, and energy dissipation for all tested specimens are discussed. The test results showed that the strength capacity of reinforced concrete columns was affected by the column cover. The increment in temperature led to a reduction in the strength-carrying capacity of the columns and increased the axial and lateral displacements. The static compressive strength was reduced by 36.84 and 48.81% when the applied temperature was 500 and 800 °C, respectively. The stiffness of the specimen with 17 mm cover was 29.27 and 46.86% less than that of 10 mm cover for axial and lateral displacement, respectively. Also, the specimen with 10 mm cover exhibited decreased energy dissipation by 1.69 and 12.54% for axial and lateral displacement.

“…The cross-sections exhibit nonlinear deformations under bending, resulting in a nonlinear distribution of the strains across them. Exposure to elevated temperatures, mainly caused by accidental fires, represents one of the most severe exposure conditions for buildings and structures [13][14]. This study aimed to determine the efficiency of lacing reinforcement in post-fire deep beams and the contribution of the tension reinforcement to the performance of the lacing after exposure to fire.…”

Section: Introductionmentioning

confidence: 99%

The Experimental and Theoretical Effect of Fire on the Structural Behavior of Laced Reinforced Concrete Deep Beams

Kareem,

Mohammed

2023

A Laced Reinforced Concrete (LRC) structural element comprises continuously inclined shear reinforcement in the form of lacing that connects the longitudinal reinforcements on both faces of the structural element. This study conducted a theoretical investigation of LRC deep beams to predict their behavior after exposure to fire and high temperatures. Four simply supported reinforced concrete beams of 1500 mm, 200 mm, and 240 mm length, width, and depth, respectively, were considered. The specimens were identical in terms of compressive strength ( 40 MPa) and steel reinforcement details. The same laced steel reinforcement ratio of 0.0035 was used. Three specimens were burned at variable durations and steady-state temperatures (one hour at 500 °C and 600 °C, and two hours at 500 °C). The flexural behavior of the simply supported deep beams, subjected to the two concentric loads in the middle third of the beam, was investigated with ABAQUS software. The results showed that the laced reinforcement with an inclination of 45˚ improved the structural behavior of the deep beams, and the lacing resisted failure and extended the life of the model. The optimal structural response was observed for the specimens. The laced reinforcement improved the failure mode and converted it from shear to flexure-shear failure. The parametric study showed that the lacing bars remarkably improved the strength of the deep beams and they were not affected more by the steady-state temperature and duration. Furthermore, a greater increase in load-carrying capacity was associated with an increase in the flexural diameter of approximately 12 and 16 mm by approximately 24.77% and 87.61%, respectively, compared to the reference LRC deep beams.