Behavior of Reinforced Concrete Members Exposed to Fire: Review Article

Abstract

Fire is one of the most severe conditions to which buildings may be exposed. However, reinforced concrete has good resistance, which makes it one of the building materials most widely used worldwide. When reinforced concrete is exposed to high temperatures, its skeletal members undergo changes that may lead to, in many cases, inclusive cracking. Beams, columns, and slabs are the most important structural elements in any concrete construction. Structural members are generally designed to satisfy the requirements of serviceability and safety limit states for various environmental conditions. Typically, structural members are created to meet a specific fire resistance grade. The characteristics of the structure and the type of occupation are just two variables that affect fire resistance. Structural fire rating's primary goals are to enable building inhabitants enough time to leave, enough time for firefighters to put out the fire, and enough time to prevent any potential structural damage. This article overviews how various reinforced concrete building structural elements behave when exposed to high temperatures. It has been found that both concrete and reinforcing bars are adversely affected by fire. Furthermore, it has been discovered that flexibility and stiffness decrease with increasing stress or the period of fire exposure. Also, the flexibility and stiffness rise with increasing structural element cross-section; however, the maximum slab deflection non-linearly decreases during the fire test. The bottom of the concrete slab begins to cool as temperatures decrease, which increases the yield strength of the bottom reinforcing and causes it to contract along with the lower half of the slab. This article also presents a review of a set of experimental and theoretical results on the thermal behavior of reinforced concrete slabs, beams, and other structural parts under different conditions and scenarios as a historical review.