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Journal : Civil Engineering Journal

POST-FIRE BEHAVIOR OF POST-TENSIONED SEGMENTAL CONCRETE BEAMS UNDER MONOTONIC STATIC LOADING Oukaili, Nazar; Izzet, Amer F.; Hekmet, Haider M.
Civil Engineering Journal Vol 6, No 5 (2020): May
Publisher : Salehan Institute of Higher Education

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.28991/cej-2020-03091515

Abstract

This paper presents a study to investigate the behavior of post-tensioned segmental concrete beams that exposed to high-temperature. The experimental program included fabricating and testing twelve simply supported beams that divided into three groups depending on the number of precasting concrete segments. All specimens were prepared with an identical length of 3150 mm and differed in the number of the incorporated segments of the beam (9, 7, or 5 segments). To simulate the genuine fire disasters, nine out of twelve beams were exposed to a high-temperature flame for one hour. Based on the standard fire curve (ASTM ? E119), the temperatures of 300?C (572?F), 500?C (932?F), and 700?C (1292?F) were adopted. Consequently, the beams that exposed to be cool gradually under the ambient laboratory condition, after that, the beams were loaded till failure to investigate the influence of the heating temperature on the performance during the serviceability and the failure stage. It was observed that, as the temperature increased in the internal layers of concrete, the camber of tested beams increased significantly and attained its peak value at the end of the time interval of the stabilization of the heating temperature. This can be attributed to the extra time that was consumed for the heat energy to migrate across the cross-section and to travel along the span of the beam and deteriorate the texture of the concrete causing microcracking with a larger surface area. Experimental findings showed that the load-carrying capacity of the test specimen, with the same number of incorporated concrete segments, was significantly decreased as the heating temperature increased during the fire event.
Flexural Behavior of Reinforced Concrete Beams with Steel-Plate Reinforced Vertical Opening Abed Shnait, Masharq; Izzet, Amer F.
Civil Engineering Journal Vol 10, No 9 (2024): September
Publisher : Salehan Institute of Higher Education

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.28991/CEJ-2024-010-09-04

Abstract

The structural response of simply supported Reinforced Concrete (RC) beams with square vertical openings is investigated in this work. Studies were conducted using seven specimens of RC beams, with the aim of comparing beams with vertical openings to those without. Meanwhile, the other beams featured carefully positioned square openings. Note that one of these beams served as the control and had no openings. Each beam was the same length (1400 mm) with a 180×120 mm cross-section. Two-point loads were applied over a span of 1200 mm throughout the testing method, with a central load placed 300 mm from the ends. The openings were positioned in the middle of the span and came in three different widths: 20, 40, and 60 mm. Openings were made using either 1.5 mm thick square steel tubing or none at all. The major goal of this study was to determine whether the steel tube could compensate for the decrease in beam strength and the impact of decreasing beam cross-section (producing opening). Correspondingly, the beam ultimate load was found to decrease by 15.75%, 24.2%, and 32.5% for opening widths of 20 mm, 40 mm, and 60 mm, respectively, as the opening width increased. On the other hand, the performance gain for beams strengthened with steel plates when steel tubes were used was 11.78%, 12.14%, and 13.28% for the respective opening widths. Doi: 10.28991/CEJ-2024-010-09-04 Full Text: PDF