Papers by Mahmoud El-Boghdadi
Arabian Journal for Science and Engineering
Steel beams with web opening have become a popular structural element nowadays owing to their sev... more Steel beams with web opening have become a popular structural element nowadays owing to their several structural and architectural benefits. This study numerically investigates a study of the behavior of steel beams with a web opening subjected to fatigue loading using the finite element software ANSYS. Simply supported I-section steel beams with a single web opening were studied under a fully reversed, uniformly distributed vertical load. Fatigue loading, material properties, and boundary conditions are discussed in detail. Finite element analysis was used to determine the effect of the web opening on the normal stress induced in the steel beam and consequently on fatigue stress life. Then, a parametric study was performed to investigate the effect of two geometric parameters (opening size $$\alpha $$ α and opening location $$\beta $$ β ). In addition, suitable fatigue categories were suggested to guarantee safety against fatigue failures. Further, an analytical method for predicti...
International Conference on Advances in Structural and Geotechnical Engineering (ICASGE’15), Hurghada, Egypt, 6-9 April 2015, 2015
Lattice steel transmission towers (LSTTs) are vital components of overhead transmission lines tha... more Lattice steel transmission towers (LSTTs) are vital components of overhead transmission lines that play an important role in supporting the electrical power grids. This paper presents different types of failures observed during full-scale experimental testing on three LSTTs. The objective of this study is to check the absolute towers capabilities and to identify the strength and safety of the steel towers under the design loads. The full- scale tests were performed at CELPI towers testing station – Bucharest – Romania. The three LSTTs were designed to carry 33 kV double circuits overhead transmission lines, the loading conditions and design complied with the relevant requirements of the technical specification of ASCE-10/97. The structural design was performed using the software of power line system (PLS-TOWER) whereas the detailed design and drawings were performed using TEKLA STRUCTURE structural engineering software. The tests were performed in accordance with the requirements of the current version of IEC 60652:2002-06 “Loading test on line towers”. Observed Failures were studied and the reasons are discussed in details. As a result, the modifications for each tower were performed in order to enhance the performance to sustain loads and decrease the overall deflection.
Journal of Engineering Research, 2021
In the last decades, steel beams with web opening were used extensively as useful structural and ... more In the last decades, steel beams with web opening were used extensively as useful structural and architectural elements due to their many advantages. In this research, steel beams with web opening subjected to static loading were modelled using the multi-purpose finite element software ANSYS and the finite element results were compared with previous research. Then, steel beams with a single web opening subjected to fatigue loading were investigated numerically. The effect of changing the location of web opening on the fatigue assessment of H section steel beams with web opening was studied taking normal stress into account. It was clear that, normal stress fatigue life of the steel beams was affected significantly by changing web opening location along the beam span when compared to a beam with solid web while the beam span, opening size and steel section were kept constant. The most convenient location of web opening along the beam span was found to be at mid span.
Journal of Constructional Steel Research, 2018
Arched beams with cellular openings (referred to here as arched cellular beams) are used as roof ... more Arched beams with cellular openings (referred to here as arched cellular beams) are used as roof beams with several practical advantages and architectural-appearance requirements. This paper presents a discussion regarding the performance of arched cellular beams. An experimental program comprising four full-scale specimens was performed. The perforated cellular arched I-sections with hinged-hinged supports under a mid-span vertical concentrated load were tested. Manufacturing, material properties, boundary conditions, and the test setup are discussed in detail in this paper. The experimental investigation was carried out to study the effects of cellular web openings, subtended angles, and radii of curvature. The failure modes and key parameters were investigated. The web buckling resistance of the experimental specimens was calculated using two models from the literature. The analytical model for straight cellular beams proposed by Lawson et al. [1] yielded feasible conservative va...
Structures, 2021
Corrugated plates are gaining increasing attention from researchers based on their recent extensi... more Corrugated plates are gaining increasing attention from researchers based on their recent extensive use in structural engineering, thanks to their potential to provide lighter and more economic structures. However, tests on the flexural behaviour of trapezoidally corrugated web girders (CWGs) are still scarce in the literature. Accordingly, the purpose of this paper is to provide the fundamental behaviour of laterally-unrestrained trapezoidally CWGs by experimental and numerical investigations. The middle parts of the specimens are loaded by pure bending moment by adopting the four-point loading process. Firstly, three CWGs are tested experimentally by changing the flange width and web height, with corrugation dimensions kept the same. The flange width varies from 80 mm to 100 mm and the web height changes from 300 mm to 400 mm. The girders are found to fail by the lateral-torsional buckling mechanism without any local flange buckling or web distortion. After that, ABAQUS software i...
Engineering Structures, 2017
Abstract Recently, there have been many attempts all over the world to reduce the own weight of t... more Abstract Recently, there have been many attempts all over the world to reduce the own weight of the superstructure of the bridges, as well as reducing the work and cost involved in construction. One attempt is to utilise the tapered (i.e. non-prismatic with varying depth) steel plate girders with corrugated webs (TPGCWs). The corrugated steel plates are widely used as structural elements in many structural applications because of their numerous favourable properties compared with traditional flat plates. Moreover, they have been used due to their aesthetical appearance, especially in the case of TPGCWs. On the other hand, the use of high strength steels (HSSs) has gained greater commercial interest over the last decades. The capabilities of these HSSs allow obtaining smaller structural parts and slender sections and less weight without compromising security. Hence, the present paper combines the advantages of the tapered corrugated webs and the HSSs by investigating the strength and behaviour of the TPGCWs built with HSSs. The corrugated webs considered in this finite element (FE) analyses have practical dimensions similar to those used in available bridges with corrugated webs. Accordingly, a nonlinear modelling, using the ABAQUS programme, was conducted on TPGCWs after validating the FE models through comparisons with the experimental results available in literature. Parametric study was, then, performed on TPGCWs to study their behaviour under shear loading using HSSs. Finally a new equation was proposed for calculating the ultimate shear strength of TPGCWs. Overall, this investigation expands the available engineering knowledge and assists in utilising the HSS, currently used in a wide range of applications, with the TPGCWs with their favourable aesthetical and structural characteristics.
Two previous published papers by the writers describing the nonlinear behavior of curved I-girder... more Two previous published papers by the writers describing the nonlinear behavior of curved I-girder web panels subjected to pure bending, were presented including experimental and theoretical analysis. The web slenderness limitation was also presented. A finite element analysis was needed to validate the applicability of the web slenderness limitation. This paper presents geometrical nonlinear finite element analysis for curved panels. To simulate the behavior of curved thin-walled panel subjected to pure bending, three dimensional model is presented. The effect of flange slenderness on the web buckling was also investigated. The flange slenderness limitation of the straight panel presented in Euro Code 3 is used for calculating the flange slenderness limitation for curved thin-walled panel.
Thin-Walled Structures, 2022
Typically, lattice steel transmission towers (LSTTs) are built using bolted connections, although... more Typically, lattice steel transmission towers (LSTTs) are built using bolted connections, although the performances of these connections are complicated. Generally, lap-splice bolted connections are used for long primary (leg) members to ensure their continuity. Herein, 17 lap-splice bolted joints, with real-scale dimensions as used in three LSTTs, are experimentally tested under compression, with the bolts being under shear. The considered three LSTTs carry 33 kV double-circuits overhead transmission lines, where the loading conditions and design are complied with the relevant requirements of the technical specification of ASCE-10/97 (2000). The main objective of this paper is to study the behaviour and failure mode of the lap-splice bolted joints of such three LSTTs, which are often considered either pinned or fully-rigid in practice. The joints relationships by means of the axial load versus joint deformation under shear forces on bolts are measured and evaluated, where the lap-splice bolted joints are found to show pre-slippage, slippage, bearing and plastic stages. The joints are found to fail due to bearing of either inner angle members or the splice plates. The axial stiffness of the lap-splice bolted joints is then obtained from these load–displacement curves. Moreover, stiffness and shear strength of the current joints are compared with the component based method (CBM), as presented in EN 1993 − 1 − 8 (2005). In this method, the structural steel joint under shear loading is treated as a multi-spring model composed of in-series springs, which enables obtaining its force–displacement relationship. The initial stiffness and strength comparison based on this simple method shows a good agreement with the experimental results. Additionally, the strength obtained by CBM is shown to conform to the experimental failure modes. Based on the results, the laboratory experimental compression tests as well as CBM estimations of bolted lapsplice joints connections are useful tools to evaluate the behaviour of these joints. Hence, they are suggested to be taken into consideration during the overall elastic design of the towers by using well calibrated finite element modelling instead of using expensive full-scale loading prototype testing method in accordance to IEC 60652 (2002).
Light-Weight Steel and Aluminium Structures: ICSAS '99, 1999
The paper presents the results of a design procedure (nongradient-based) that has been automated ... more The paper presents the results of a design procedure (nongradient-based) that has been automated to obtain a minimum weight design of nonuniform stiffened steel plate girders. The procedure allows the use of either the ASD guidelines or the LRFD guidelines to obtain the required design. The results of numerical studies performed to obtain a minimum weight design of a three-span nonuniform stiffened plate girder are summarized to: (1) highlight differences between values obtained from these two design procedures; (2) emphasize effectiveness of applying the procedure to a design problem as compared to the use of a generalized gradient-based design procedure.
TECHNO-PRESS , STRUCTURAL ENGINEERING AND MECHANICS, 1999
A study was undertaken to capture the behavior and response of cap-plate type moment connections ... more A study was undertaken to capture the behavior and response of cap-plate type moment connections used in industrial buildings. Such connections typically represent the semi-rigid class and therefore their response must be accounted for in the analysis and design. A number of beam-column connections were tested to obtain the evolution of moment-rotation (M-phi) curves and to collect information related to the behavior of such connections. With this as a background, the analytical representation of M-phi curve has been proposed for cap-plate type connections.
Journal of Engineering Research, 2021
This paper uses the multi-purpose software ABAQUS to create a three-dimensional finite element mo... more This paper uses the multi-purpose software ABAQUS to create a three-dimensional finite element model of an extended end plate connection to analyze and compare the behaviour of mild steel and high-strength steel endplate connections. The numerical model's results are calibrated against reported experimental results to ensure that it can simulate and analyze both the overall and detailed behaviour of different types of bolted endplate steel connections. The results of the study compare and analyze the moment-rotation relationships and the behaviour characteristics of the connection with mild steel and high strength steel. A parametric study is then carried out using the verified FEM to examine many parameters such as endplate thickness, bolt diameter, and steel grade of the endplate. The results of this study indicate that for extended endplate connections, increasing the endplate thickness or the bolt diameter leads to a marked increase of both the strength and the stiffness but it reduces the ductility of the connections. Also, increasing the endplate steel grade results in higher strength but lower ductility.
IOP Conference Series: Materials Science and Engineering
Journal of Constructional Steel Research, 2004
In this paper, the elastic lateral stability of castellated steel beams with hexagonal opening un... more In this paper, the elastic lateral stability of castellated steel beams with hexagonal opening under concentrated load is conducted. 3D elastic finite element (FE) model is performed by using FE software package ABAQUS. A parametric study is made on compact sections to investigate the effect of the slenderness ratio of web () w
Thin-Walled Structures, 2009
This paper presents a comparative experimental study between stiffened and unstiffened stainless ... more This paper presents a comparative experimental study between stiffened and unstiffened stainless steel hollow tubular stub columns using the austenitic stainless steel grade EN 1.4301 (304). Stainless steel structural shapes are becoming increasingly complex as cold-forming techniques are advancing. The unstiffened stainless steel tubular stub sections were fabricated by welding four angles or two channels tip-to-tip, whereas the stiffened sections were fabricated by welding four lipped angles or two lipped channels at the lips. Therefore, the stiffeners were formed at the mid-depth of the sections. In total, five columns without stiffeners and five columns with stiffeners were tested. Series of tests were performed to investigate the effects of cross-section shape on the behaviour and strength of stainless steel tubular stub columns. The measured average overall depth-to-width ratios (aspect ratio) varied from 1.0 to 1.8. The depth-to-plate thickness ratio of the tube sections varied from 60 to 90. Different lengths of columns were selected to fix the length-to-depth ratio to a constant value of 3. The specimens were subjected to uniform axial compression. The column strengths, load–axial strain relationships and failure modes of the columns are presented. The column strengths obtained from the experimental study were compared with the design strengths calculated using the European Code for cold-formed stainless steel structures and the ASCE Standard. The results of the experimental study showed that the design rules specified in European specifications and ASCE standard generally overestimate the column strengths of stainless steel square and rectangular hollow section stub columns fabricated by cold-forming and welding.
Journal of Constructional Steel Research, 2009
This paper presents a comparative study between stiffened and unstiffened concrete-filled stainle... more This paper presents a comparative study between stiffened and unstiffened concrete-filled stainless steel hollow tubular stub columns using the austenitic stainless steel grade EN 1.4301 (304). Finite element analysis of concrete-filled stainless steel unstiffened tubular stub columns is constructed herein based on the confined concrete model recently available in the literature. It is then compared with the experimental results of concrete-filled stainless steel stiffened tubular stub columns. The stiffened stainless steel tubular sections were fabricated by welding four lipped angles or two lipped channels at the lips. The longitudinal stiffener of the column plate was formed to avoid shrinkage of the concrete and to act as a continuous connector between the concrete core and the stainless steel tube. The behavior of the columns was investigated using two different nominal concrete cubic strengths of 30 and 60 MPa. The overall depth-towidth ratios (aspect ratio) varied from 1.0 to 1.8. The depth-to-plate thickness ratio of the tube sections varied from 60 to 90. The stiffened and unstiffened concrete-filled stainless steel tube specimens were subjected to uniform axial compression over the concrete and stainless steel tube to force the entire section to undergo the same deformations by blocking action. The ABAQUS 6.6 program, as a finite element package, is used in the current work. The results of the comparative study showed that the stainless steel tubes in stiffened concrete-filled columns offered a high average of increase in the confinement of the concrete core than that of the unstiffened concrete-filled columns.
Journal of Constructional Steel Research, 2009
An experimental investigation was made to study the behaviour of space steel and composite semiri... more An experimental investigation was made to study the behaviour of space steel and composite semirigid joints. The effect of loading from the minor direction on the main direction of semi-rigid joints was considered. Five full-scale tests were performed on semi-rigid space steel and composite extended endplates joints. A three-dimensional finite element model is proposed using ANSYS software for the analytical investigation. A comparative study between the present numerical model and the experimental results is presented to establish the validity of the proposed model. Also, an application was made on space frame to show the effect of joint rigidity using a beam-element model and this was verified with previous studies.
… of Constructional Steel …, 2009
This paper presents a comparative study between stiffened and unstiffened concrete-filled stainle... more This paper presents a comparative study between stiffened and unstiffened concrete-filled stainless steel hollow tubular stub columns using the austenitic stainless steel grade EN 1.4301 (304). Finite element analysis of concrete-filled stainless steel unstiffened tubular stub columns is constructed herein based on the confined concrete model recently available in the literature. It is then compared with the experimental results of concrete-filled stainless steel stiffened tubular stub columns. The stiffened stainless steel tubular sections were fabricated by welding four lipped angles or two lipped channels at the lips. The longitudinal stiffener of the column plate was formed to avoid shrinkage of the concrete and to act as a continuous connector between the concrete core and the stainless steel tube. The behavior of the columns was investigated using two different nominal concrete cubic strengths of 30 and 60 MPa. The overall depth-towidth ratios (aspect ratio) varied from 1.0 to 1.8. The depth-to-plate thickness ratio of the tube sections varied from 60 to 90. The stiffened and unstiffened concrete-filled stainless steel tube specimens were subjected to uniform axial compression over the concrete and stainless steel tube to force the entire section to undergo the same deformations by blocking action. The ABAQUS 6.6 program, as a finite element package, is used in the current work. The results of the comparative study showed that the stainless steel tubes in stiffened concrete-filled columns offered a high average of increase in the confinement of the concrete core than that of the unstiffened concrete-filled columns.
Engineering Structures, 2009
This paper presents an experimental investigation on concrete-filled normal-strength stainless st... more This paper presents an experimental investigation on concrete-filled normal-strength stainless steel stiffened tubular stub columns using the austenitic stainless steel grade EN 1.4301 (304). The stiffened stainless steel tubes were fabricated by welding four lipped angles or two lipped channels at the lips. Therefore, the stiffeners were formed at the mid-depth of the sections. In total, five hollow columns and ten concrete-filled columns were tested. The longitudinal stiffener of the column plate was formed to avoid shrinkage of the concrete and to behave as a continuous connector between the concrete core and the stainless steel tube. The behavior of the columns was investigated using two different nominal concrete cubic strengths of 30 and 60 MPa. A series of tests was performed to investigate the effects of cross-section shape and concrete strength on the behavior and strength of concrete-filled stainless steel stiffened tubular stub columns. The measured average overall depth-to-width ratios (aspect ratio) varied from 1.0 to 1.8. The depth-to-plate thickness ratio of the tube sections varied from 60 to 90. Different lengths of columns were selected to fix the length-to-depth ratio to a constant value of 3. The concrete-filled stiffened stainless steel tubular columns were subjected to uniform axial compression over the concrete core and the stainless steel tube to force the entire section to undergo the same deformations by blocking action. The column strengths, load–axial strain relationships and failure modes of the columns are presented. Several comparisons were made to evaluate the test results. The results of the experimental study showed that the design rules, as specified in the European specifications and the ASCE, are highly conservative for square and rectangular cold-formed concrete-filled normal-strength stainless steel stiffened stub columns.
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Papers by Mahmoud El-Boghdadi