Structural Engineering Commons^™

Fire-Resistance Testing Procedures For Construction Elements—A Review, Shashikant Chaturvedi, Ajitanshu Vedrtnam, Maged A. Youssef, Martin T. Palou, Gonzalo Barluenga, Kishor Kalauni

Civil and Environmental Engineering Publications

Fire accidents are a significant risk to human life and civil infrastructure. As a countermeasure, the regulatory bodies of different countries have established standards for evaluating the performance of construction elements during fire exposure. ISO 834 is the globally accepted fire-resistance testing standard. Other standards include ASTM E119, BS 476, IS 3809, JIS A 1304, AS 1503, EN 1363, and GB/T 9978, which are utilized by the US, Britain, India, Japan, Australia, Europe, and China, respectively. This article presents a summary and comparison of the fire-resistance testing standards. In reality, standard tests for isolated structural members may not efficiently portray …

Seismic Performance Of Ductile Corrosion-Free Reinforced Concrete Frames, Mohamed Meshaly, Maged A. Youssef, Ahmed Elansary

Civil and Environmental Engineering Publications

Corrosion of steel bars is the main cause of the deterioration of reinforced concrete (RC) structures. To avoid this problem, steel rebars can be replaced with glass-fiber-reinforced-polymer (GFRP). However, the brittle behaviour of GFRP RC elements has limited their use in many applications. The use of shape memory alloy (SMA) and/or stainless steel (SS) rebars can solve this problem, because of their ductile behaviour and corrosion resistance. However, their high price is a major obstacle. To address issues of ductility, corrosion, and cost, this paper examines the hybrid use of GFRP, SS, and SMA in RC frames. The use of …

Structural Performance Of Single-Skin Glass Façade Systems Exposed To Fire, Mohamed Badr, Maged A. Youssef, Salah El-Din F. El-Fitiany, Ajitanshu Vedrtnam

Civil and Environmental Engineering Publications

Purpose

Understanding the structural performance of external glass curtain walls (façades) during fire exposure is critical for the safety of the occupants, as their failure can lead to fire spread throughout the entire building. This concern is magnified by the recent increase in fire incidents and wildfires. This paper presents the first simplified technique to model single skin façades during fire exposure, and, then utilizes it to examine the structural behaviour of vertical, inclined, and oversized façade panels.

Design/methodology/approach

The proposed technique is based on conducting simplified heat transfer calculations, and, then utilizing a widely used structural analysis software to …

Residual Axial Behavior Of Restrained Reinforced Concrete Columns Damaged By A Standard Fire, M. Monir M. Ajan Alhadid, Maged A. Youssef

Civil and Environmental Engineering Publications

A simplified procedure to predict the residual axial capacity and stiffness of both rectangular and circular reinforced concrete (RC) columns after exposure to a standard fire provides the means to replace the current descriptive methods. The availability of such a procedure during the design phase provides engineers with the flexibility to come up with better designs that ensure safety. In this paper, finite difference heat transfer and sectional analysis models are combined to determine the axial behavior of RC columns with various end-restraint conditions at different standard fire durations. The influence of cooling phase on temperature distribution and residual mechanical …

Influence Of Natural Fire Development On Concrete Compressive Strength, Robert T. Kuehnen, Maged A. Youssef, Salah El-Din F. El-Fitiany

Civil and Environmental Engineering Publications

With increasing acceptance of performance-based design principles in the field of fire safety, it is imperative to accurately define the behaviour of materials during fire exposure. Real-world fire events, otherwise referred to as natural fires, are defined by four characteristics: heating rate, maximum temperature, exposure duration, and cooling rate. Each of these four characteristics influences concrete’s behaviour in a different manner. In this paper, the available experimental work for concrete, tested at elevated temperatures, is examined to identify the influence of the four natural fire characteristics on concrete compressive strength. This review focuses on normal strength concrete tests only, omitting …

Seismic Performance Of Hybrid Corrosion-Free Self-Centering Concrete Shear Walls, Emad A. Abraik, Maged A. Youssef, Salah El-Din F. El-Fitiany

Civil and Environmental Engineering Publications

Reinforced concrete (RC) walls are extensively used in high-rise buildings to resist lateral loads, while ensuring an adequate level of ductility. Durability problems, including corrosion of conventional steel reinforcements, necessitate exploring alternative types of reinforcement. The use of glass fiber reinforced polymer (FRP) bars is a potential solution. However, these bars cannot be used in seismic applications because of their brittleness and inability to dissipate seismic energy. Superelastic shape memory alloy (SMA) is a corrosion-free material with high ductility and unique self-centering ability. Its high cost is a major barrier to use in construction projects. The clear advantage of utilizing …

Effect Of Non-Uniform Temperature Exposure On The Out-Of-Plane Bending Performance Of Ordinary Laminated Glass Panels, Maged A. Youssef, Ajitanshu Vedrtnam, Chiara Bedon, Shashikant Chaturvedia

Civil and Environmental Engineering Publications

Among the open design issues for structural laminated glass (LG) elements, their mechanical performance during fire exposure stands as a safety concern. This issue is the focus of this paper. An experimental investigation is conducted to evaluate the effect of non-uniform thermal gradients on the out-of-plane bending capacity of standard LG specimens. The pre-fracture, cracking, and post-fracture performances of LG panels were examined using a three-point bending setup. The bending tests were carried out on un-heated LG samples and heated samples, which were either hot or cooled down. The reliability of available analytical and numerical methods to predict the out-of-plane …

Ductility And Overstrength Of Shape-Memory-Alloy Reinforced-Concrete Shear Walls, Emad A. Abraik, Maged A. Youssef

Civil and Environmental Engineering Publications

The unique properties of superelastic shape-memory-alloy (SMA) bars have motivated researchers to investigate their use as reinforcing bars for concrete elements. They were found to decrease seismic residual deformations, while increasing seismic inelastic deformations. This characteristic deformation behaviour requires an assessment of the seismic design parameters of SMA reinforced concrete walls. This paper addresses this requirement by evaluating their ductility and overstrength factors. A total of 972 walls were analyzed under a quasi-static lateral load. Suitable values for the overstrength and ductility factors were estimated for two proposed locations of SMA bars. FEMA P695 was then utilized to evaluate the …

Simplified Structural Analysis Of Framed Ordinary Non-Tempered Glass Panels During Fire Exposure, Amer Sabsabi, Maged A. Youssef, Salah El-Din F. El-Fitiany, Ajitanshu Vedrtnam

Civil and Environmental Engineering Publications

Ordinary non-tempered glass is one of the most widely used materials in the construction industry. Knowing its fire resistance is essential to ensure the safety of emergency personnel as its failure increases the oxygen supply and causes a rapid spread of the fire (flashover phenomenon). Existing approaches for evaluating the structural fire safety of glass façades require expensive experimental tests and/or extensive knowledge of Finite Element modeling. This paper provides a simplified, rational, and reliable approach to assess the structural capacity of ordinary glass panels during fire exposure. A simplified method is developed to predict the temperature difference between …

Seismic Performance Of Rc Beam-Column Edge Joints Reinforced With Austenite Stainless Steel, C Xu, Moncef L. Nehdi, Maged A. Youssef, L. V. Zhang

Civil and Environmental Engineering Publications

Using stainless steel (SS) reinforcement can mitigate colossal corrosion damage inflicted to reinforced concrete (RC) structures worldwide. However, there is still dearth of studies on the seismic behavior of SS-RC structures. Hence, quasi-static tests were carried out in this study to explore the seismic performance of three RC frame edge joint specimens reinforced with SS having strength grade of 500 and one control RC specimen made with grade 400 normal steel. RC edge frame joints reinforced with ordinary steel and SS exhibited similar bending-shear failure patterns at the beam root. The load bearing capacity of the SS-RC edge fame joint …

Experimental And Numerical Structural Assessment Of Transparent And Tinted Glass During Fire Exposure, A Vedrtnam, C Bedon, Maged A. Youssef, M Wamiq, Amer Sabsabi, S Chaturvedi

Civil and Environmental Engineering Publications

Transparency, illumination, aesthetic and energy requirements have considerably increased the use of glass in modern high-rise buildings. During fire exposure, fracture and shattering of windows and facades accelerate the spread and severity of fire, which increases the risk for the occupants and the amount of structural damage. This paper aims at analyzing the effect of non-uniform thermal gradients on the flexural capacity of ordinary glass panels. Both transparent and tinted glass panels are considered to account for widely-used glass compositions. The bending response of fire-damaged glass panels is experimentally explored considering different durations of thermal exposure. The thermal breakage due …

Performance-Based Design Of Rc Columns Using An Equivalent Standard Fire, Robert T. Kuehnen, Maged A. Youssef, Salah El-Din F. El-Fitiany

Civil and Environmental Engineering Publications

The extreme variability of natural compartment fires poses a significant challenge in the process of performance-based fire design. To reduce this variability, the severity of a natural fire can be related to that of a standard fire, known as a time equivalent (te). In this paper, the applicability of a time equivalent, previously derived based on the average internal temperature profile (AITP) that develops within reinforced concrete (RC) beams exposed to fire from three sides, is examined for RC columns exposed to fire from four sides. A parametric study is presented to examine the suitability of the …

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 …

Seismic Fragility Assessment Of Superelastic Shape Memory Alloy Reinforced Concrete Shear Walls, Emad A. Abraik, Maged A. Youssef

Civil and Environmental Engineering Publications

Mitigation of seismic damage can be achieved through self-centering techniques. One of the potential techniques involves the use of Superelastic Shape Memory Alloy (SE-SMA) bars in Reinforced Concrete (RC) structures. This study explores the use of such bars in the plastic-hinge regions of RC walls. The seismic performance and vulnerability of SE‑SMA RC walls of ten- and twenty-story buildings are analytically assessed using fragility curves. The maximum inter-story drift, residual drift, and fragility are evaluated using multi strip analysis. The results clearly demonstrate the superior seismic performance of SE-SMA RC walls as compared to steel RC walls.

Seismic Performance Of Modular Steel Frames Equipped With Shape Memory Alloy Braces, Papia Sultana, Maged A. Youssef

Civil and Environmental Engineering Publications

The demand for modular steel buildings (MSBs) has increased because of the improved quality, fast on-site installation, and lower cost of construction. Steel braced frames are usually utilized to form the lateral load resisting system of MSBs. During earthquakes, the seismic energy is dissipated through yielding of the components of the braced frames, which results in residual drifts. Excessive residual drifts complicate the repair of damaged structures or render them irreparable. Researchers have investigated the use of superelastic shape memory alloys (SMAs) in steel structures to reduce the seismic residual deformations. This study explores the potential of using SMA braces …

Shape Memory Alloy Reinforced Concrete Frames Vulnerable To Strong Vertical Excitations, M A. Elfeki, Maged A. Youssef

Civil and Environmental Engineering Publications

Reinforced concrete (RC) framed buildings dissipate the seismic energy through yielding of the reinforcing bars. This yielding jeopardizes the serviceability of these buildings as it results in residual lateral deformations. Superelastic shape memory alloys (SMAs) can recover inelastic strains by stress removal. This paper extends previous research by the authors that optimized the use of SMA bars in RC frames considering the horizontal seismic excitation by addressing the effect of the vertical seismic excitation. A steel RC six-storey building designed according to current seismic standards is considered as case study. Five different earthquake records with strong vertical components are …

Ductile Corrosion-Free Gfrp-Stainless Steel Reinforced Concrete Elements, Maged A. Youssef, Mohamed E. Meshaly, Ahmed Elansary

Civil and Environmental Engineering Publications

Corrosion of steel rebars is known to cause deterioration of concrete structures that can lead to catastrophic failures. To mitigate this problem, steel rebars can be replaced with Glass Fiber-Reinforced Polymer (GFRP) rebars. However, the lack of ductility of GFRP-reinforced elements has prevented their use in many structural applications, especially in seismic areas. Stainless Steel (SS) rebars are corrosion resistant and have adequate energy absorption and ductility. However, they are much more expensive than steel rebars. This paper proposes the combined use of SS and GFRP rebars to achieve ductile and corrosion-free elements. The first challenge for such a proposal …

Prediction Of Local Seismic Damage In Steel Moment Resisting Frames, Papia Sultana, Maged A. Youssef

Civil and Environmental Engineering Publications

Steel moment resisting frames (SMRFs) are widely utilized as a lateral load resisting system. Their seismic performance is usually assessed by examining the maximum value of inter-storey drift (MID) of all floors. The accuracy of such assessment is debatable given the wide spread of values of MID at collapse that exist in the literature. In this study, a simplified method to define the failure inter-storey drift for each floor of a SMRF is proposed. The method was validated with the experimental and analytical studies by other researchers. Three- and ten-storey SMRFs were considered to further validate the proposed method. The …

Shear Capacity Of Rc Beams At Elevated Temperatures, Maged A. Youssef, Mohamed Diab, Salah El-Din F. El-Fitiany

Civil and Environmental Engineering Publications

Fire safety is a critical criterion for designing reinforced concrete structures. With the introduction of performance-based design, structural engineers need design tools to assess the capacity of different elements during fire exposure. This paper proposes an analytical method to predict the shear capacity of reinforced concrete beams exposed to elevated temperatures. The proposed method extends the use of existing ambient temperature methods by accounting for the effect of elevated temperatures on material properties. It involves heat transfer analysis, evaluation of the material properties at elevated temperatures, and application of the modified compression field theory to estimate the shear capacity. The …

Analytical Modeling Of The Interface Between Lightly Roughened Hollowcore Slabs And Cast-In-Place Concrete Topping, Aiham Adawi, Maged A. Youssef, Mohamed E. Meshaly

Civil and Environmental Engineering Publications

Hollowcore slabs are commonly used in different types of structures. They are usually topped with a 50 mm concrete topping. Structural engineers can use this topping to increase the slab load carrying capacity. North American design standards relate the horizontal shear strength at the interface between hollowcore slabs and the concrete topping to the slab surface roughness. This paper presents results of four push-off tests on hollowcore slabs supplied by two manufacturers and roughened using a conventional steel broom. The tested slabs sustained higher horizontal shear stresses than those specified by the design standards. Utilizing the data from the push-off …

Seismic Capacity Of Reinforced Concrete Interior Flat Plate Connections, Maged A. Youssef, A O. Chowdhury, Mohamed E. Meshaly

Civil and Environmental Engineering Publications

The demand for modular steel buildings (MSBs) has increased because of the improved quality, fast on-site installation, and lower cost of construction. Steel braced frames are usually utilized to form the lateral load resisting system of MSBs. During earthquakes, the seismic energy is dissipated through yielding of the components of the braced frames, which results in residual drifts. Excessive residual drifts complicate the repair of damaged structures or render them irreparable. Researchers have investigated the use of superelastic shape memory alloys (SMAs) in steel structures to reduce the seismic residual deformations. This study explores the potential of using SMA braces …