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Equivalent Standard Fire Duration To Evaluate Internal Temperatures In Natural Fire Exposed Rc Beams, Robert T. Kuehnen, Maged A. Youssef

Civil and Environmental Engineering Publications

With the recent shift towards performance-based fire design, practical methods to account for natural fire loading when designing concrete structures are needed. Available design methods and analysis approaches are based on standard fire curves. To apply these methods, a natural fire event can be converted to a standard fire with a specific duration (time equivalent). However, existing time equivalents often ignore the influence of internal temperature gradients on the section behaviour, which is unacceptable for concrete structures.

This paper introduces a time equivalent method suitable for reinforced concrete (RC) beams exposed to natural fire. The method is based on the …

Ductile Corrosion-Free Self-Centering Concrete Elements, Maged Youssef, Mohamed E. Meshaly, Ahmed Elansary

Civil and Environmental Engineering Publications

Corrosion is a major factor in the deterioration of reinforced concrete (RC) structures. To mitigate this problem, steel bars can be replaced with glass-fiber-reinforced-polymer (GFRP) bars. However, the lack of ductility of GFRP-RC elements has prevented their use in many structural applications, especially in seismic areas. Superelastic shape memory alloy (SMA) bars have been proposed to be used in seismic areas because of their self-centering characteristics. Also, they have the added advantage of being corrosion resistant. This paper examines the combined use of SMA and GFRP bars to achieve ductile self-centering and corrosion-free elements. The first challenge for such a …

Flexural Behaviour Of Superelastic Shape Memory Alloy Reinforced Concrete Beams During Loading And Unloading Stages, Yamen Ibrahim Elbahy, Maged Youssef

Civil and Environmental Engineering Publications

Trend of using smart structures, which can adjust when exposed to severe unexpected loading, is increasing. One of the methods to achieve such structures relies on smart materials. For example, replacing conventional steel reinforcing bars in Reinforced Concrete (RC) structures with superelastic Shape Memory Alloy (SMA) bars significantly reduces the residual deformations caused by post-yielding behaviour. This paper provides in-depth understanding of the flexural behaviour of SMA RC beams. A sectional analysis method, which predicts the flexural behaviour of SMA RC beams during both loading and unloading stages, is adopted and validated using available experimental data. An extensive parametric study …

Seismic Performance Of Reinforced Concrete Frames Retrofitted Using External Superelastic Shape Memory Alloy Bars, Yamen Ibrahim Elbahy, Maged A. Youssef, Mohamed E. Meshaly

Civil and Environmental Engineering Publications

Pre-1970s designed and built reinforced concrete frame structures are considered unsafe when subjected to seismic loads. Insufficient anchorage of the beam reinforcement in the beam-column joints of these structures is considered a main deficiency. Newly built frame structures are seismically designed for safety, where high inelastic deformations can occur under moderate to strong earthquakes. Minimizing these inelastic deformations makes the structure repairable. One way to minimize these residual deformations is by using smart materials such as superelastic shape memory alloys (SMAs). In this paper, the seismic performance of RC frames retrofitted using external superelastic SMA bars is investigated and compared …