The Honeycombed Damage Effect on UHPFRC Strengthened Short Column under Eccentric Load

Abstract

This research study aims to investigate the behavior of reinforced concrete columns with a honeycomb-damaged ratio under the effect of eccentric loading at the end of the effective length of the column. The experimental analyses were conducted on nine columns with a total height of 950 mm and a cross-section area of (120*120) mm to evaluate the impact of various factors on column behavior. The total columns had two corbel heads for applying the loads. All column specimens were tested under eccentric load until failure with an eccentricity ratio equal to (10/12). These factors include the defect ratio (35% and 70%) as a part of the specimen cross-sectional area at (L/4), strengthening of UHPFRC jacket thickness (15 and 30) mm and the side of strengthening (laminates 2-sides and full casting 4-sides). The honeycomb defect has been identified via foam slicing as an indicator of specimen failure. Furthermore, the bonding procedure between the new and old layers included roughening the old surface by grinding, followed by the application of epoxy resin for adhesion. The honeycombed specimens were repaired with UHPFRC before the test. According to the results of the tests, the application of the UHPFRC jacket to strengthen concrete columns resulted in improvements within the areas of ultimate load resistance, stiffness, energy absorption, and ductility. Additionally, the honeycomb-damaged ratio of the column specimens, the thickness of the UHPFRC jacket, and the side of strengthening all had a role in determining the amount of these increases. All of the column specimens failed when subjected to various levels of load. Depending on the experimental results, the gain in strength, stiffness, ductility, toughness, failure mode, and load versus displacement were recorded, illustrated and discussed.