Boshra A Eltaly - Academia.edu (original) (raw)

Papers by Boshra A Eltaly

Research paper thumbnail of Response of Reinforced Concrete Box Girders Strengthened with composite Materials

Research Square (Research Square), May 25, 2022

The current research includes the results of a practical and numerical program to determine the b... more The current research includes the results of a practical and numerical program to determine the best way to enhance the behavior of RC box beams where the practical program relied on casting and testing 15 samples under bending. The factors that were taken into account were the use of ferrocement laminate at the tensile side or in the form of a U-shape, the number of meshes, as well as its type (welded or expanded) and the use of composite materials (CFRP, GFR). For composite materials, the strengthening was carried out in different ways, where it was applied at the tensile side only and wrapping the composite material around the web like a U-shape along the total beam's length or as strips with different sizes and spacing. The outcomes showed that the girders strengthened by 4 GFRP and 1 CFRP layers as a U-shaped have the highest service load and ultimate load.

Research paper thumbnail of Behavior of reinforced concrete stair slabs strengthened with steel plates and near surface mounted steel bars

Research paper thumbnail of Behavior of reinforced concrete ring beams strengthened with sustainable materials

Research paper thumbnail of Enhancing the behavior of reinforced concrete box girders under Two-point Loading: Numerical and experimental investigations

Research paper thumbnail of Seismic response of a full-scale wind turbine tower using experimental and numerical modal analysis

International Journal of Advanced Structural Engineering

Wind turbine technology has developed tremendously over the past years. In Egypt, the Zafarana wi... more Wind turbine technology has developed tremendously over the past years. In Egypt, the Zafarana wind farm is currently generating at a capacity of 517 MW, making it one of the largest onshore wind farms in the world. It is located in an active seismic zone along the west side of the Gulf of Suez. Accordingly, seismic risk assessment is demanded for studying the structural integrity of wind towers under expected seismic hazard events. In the context of ongoing joint Egypt-US research project ''Seismic Risk Assessment of Wind Turbine Towers in Zafarana wind Farm Egypt'' (Project ID: 4588), this paper describes the dynamic performance investigation of an existing Nordex N43 wind turbine tower. Both experimental and numerical work are illustrated explaining the methodology adopted to investigate the dynamic behavior of the tower under seismic load. Field dynamic testing of the full-scale tower was performed using ambient vibration techniques (AVT). Both frequency domain and time domain methods were utilized to identify the actual dynamic properties of the tower as built in the site. Mainly, the natural frequencies, their corresponding mode shapes and damping ratios of the tower were successfully identified using AVT. A vibration-based finite element model (FEM) was constructed using ANSYS V.12 software. The numerical and experimental results of modal analysis were both compared for matching purpose. Using different simulation considerations, the initial FEM was updated to finally match the experimental results with good agreement. Using the final updated FEM, the response of the tower under the AQABA earthquake excitation was investigated. Time history analysis was conducted to define the seismic response of the tower in terms of the structural stresses and displacements. This work is considered as one of the pioneer structural studies of the wind turbine towers in Egypt. Identification of the actual dynamic properties of the existing tower was successfully performed based on AVT. Using advanced techniques in both the field testing and the numerical investigations produced reliable FEM specific for the tested tower, which can be further used in more advanced structural investigations for improving the design of such special structures. Keywords Wind turbine tower Á Ambient vibration test Á Zafarana wind farm Á Time history analysis Á Seismic response

Research paper thumbnail of Ferrocement composite columns incorporating hollow core filled with lightweight concrete

Research paper thumbnail of Experimental and FE simulations of ferrocement columnsincorporating composite materials

Structural Engineering and Mechanics, 2017

In this study, 10 ferroconcrete concrete (FC) beams with lightweight cores reinforced with welded... more In this study, 10 ferroconcrete concrete (FC) beams with lightweight cores reinforced with welded steel mesh as a shear reinforcement were evaluated under three-point bending tests along with two conventionally normal-weight concrete (NWC) beams. Expanded polystyrene and lightweight aerated autoclaved brick wastes were used to create lightweight core concrete. The main factors include the type of lightweight concrete used for the core, beam concrete type, the form and number of holes, the existing steel mesh fabric, the hollow, and the hole placement. This study was done on the tested beams' ductility index, failure modes, first cracking loads and associated deflections, and ultimate loads besides corresponding deflections. Experimental results showed that the use of FC, various filling materials, and welded steel meshes in place of traditional stirrups enhanced the ultimate load by 36.6-107.3%, the ultimate deflection by 6-272%, and the ductility by 89-1155% when referenced to a control NWC beam. When the holing ratio increased from 10 to 20%, the ductility of FC beams was enhanced by 307.7%. Proposed equations were developed to predict the ultimate load and bending moment capacity of FC beams while taking into account the compressive strength of the beam body and filling material, the holing ratio, the tensile reinforcement ratio, and the volume fraction of the steel mesh. Highlights • This study is focusing on structural performance of ferrocement beams with lightweight cores reinforced with steel mesh fabric as a shear reinforcement. • Lightweight core concrete with steel mesh fabric reinforcement was made either using lightweight aerated autoclaved brick aggregate (LAABA) or expanded polystyrene (EP). • Impact of core lightweight concrete type, shape/number of holes, existing steel mesh fabric, concrete type, existing hollow core, positioning of hole on structural performance of the beams were performed. • Structural performance factors such ductility index, failure mechanism, first cracking loads and deflections and ultimate loads and deflections were studied.

Research paper thumbnail of Structural Performance of Ferrocement Beams Incorporating Longitudinal Hole Filled with Lightweight Concrete

International Journal of Concrete Structures and Materials

In this study, 10 ferroconcrete concrete (FC) beams with lightweight cores reinforced with welded... more In this study, 10 ferroconcrete concrete (FC) beams with lightweight cores reinforced with welded steel mesh as a shear reinforcement were evaluated under three-point bending tests along with two conventionally normal-weight concrete (NWC) beams. Expanded polystyrene and lightweight aerated autoclaved brick wastes were used to create lightweight core concrete. The main factors include the type of lightweight concrete used for the core, beam concrete type, the form and number of holes, the existing steel mesh fabric, the hollow, and the hole placement. This study was done on the tested beams' ductility index, failure modes, first cracking loads and associated deflections, and ultimate loads besides corresponding deflections. Experimental results showed that the use of FC, various filling materials, and welded steel meshes in place of traditional stirrups enhanced the ultimate load by 36.6–107.3%, the ultimate deflection by 6–272%, and the ductility by 89–1155% when referenced to ...

Research paper thumbnail of Dynamic Behavior of A Full Scale Wind Turbine Tower Under Seismic Loading

Fifth International Conference On Advances in Civil, Structural and Mechanical Engineering -ACSM 2016, 2016

This paper presents the dynamic investigation of an existing wind turbine tower. Both experimenta... more This paper presents the dynamic investigation of an existing wind turbine tower. Both experimental and numerical analyses were performed to assess the structural response of the tower under seismic load. Field ambient vibration test was applied to identify the actual dynamic properties experimentally. A vibration based finite element model was built in ANSYS to conduct the seismic response analysis. The tower shown to survive moderate earthquakes as it is located in Zafarana wind farm in Egypt, a zone lies by the red sea known for its historical seismic activity.

Research paper thumbnail of Retrofitting Notch Damaged Box Steel Beams with Composite Materials

KSCE Journal of Civil Engineering, 2017

An experimental program was designed to investigate the structural behavior of retrofitted notch ... more An experimental program was designed to investigate the structural behavior of retrofitted notch damaged box steel beams using Fiber-Reinforced Polymer (FRP) under flexure up to failure. The experimental program included twelve box steel specimens; one intact specimen, one notched specimen and ten notches damaged specimen and repaired with FRP sheets. All the tested beams have 1000 mm length. The notches specimens were notched at the tension flanges at 400 mm distance from the beam edge to simulate a localized and non-uniformly distributed deterioration along the beam length. The beams were repaired by bonding the FRP to the tension flange only, and the sheets were wrapped to cover a part of the two webs for the two beam halves or for the half of the beam that includes the notch with different heights. All the tested beams were simulated using a Finite Element (FE) program, and the FE model gives good results in comparison with the test results. The presented results indicate that wrapping CFRP sheet around the two webs for the half of the beam that includes the notch only gives an acceptable structural performance in comparing with wrapping CFRP sheet around the two webs for two halves of the beam and in this beam, the difference in the deflections of the two halves of the beam at the ultimate load does not increase than 3.2%.

Research paper thumbnail of Structural behavior of recycled aggregates concrete filled steel tubular columns

Challenge Journal of Concrete Research Letters, 2017

This paper presents an experimental and numerical investigation to determine the behavior of stee... more This paper presents an experimental and numerical investigation to determine the behavior of steel tubular columns filled with recycled aggregates concrete up to failure under constant axial compression loads. The experimental program included two steel tube columns, four recycled concrete columns and eight composite columns filled with different types of recycled coarse aggregates (granite and ceramic). Different percentages of recycled coarse aggregates: 0, 25 and 50 of the percentage of the coarse aggregates (dolomite) were used. The results of the numerical model that was employed by the finite element program, ANSYS, were compared with the experimental results. The results of the experimental study and the finite element analysis were compared with the design equations using different national building codes: AISC1999, AISC2005 and EC4. The results indicated that the recycled aggregates concrete infill columns have slightly lower but comparable ultimate capacities compared with ...

Research paper thumbnail of Damage Detection of Ferrocement Tanks Using Experimental Modal Analysis and Finite Element Analysis

Concrete Research Letters, Sep 13, 2013

In the recent years, structural health monitoring for civil structures using experimental modal a... more In the recent years, structural health monitoring for civil structures using experimental modal analysis has been developed. Experimental modal analysis is the process of determining the dynamic parameters (frequencies, damping factors, modal vectors and modal scaling) of a linear, time invariant system by way of an experimental approach. It began in 1940's in aircraft then it used in civil structures since the advent of the digital mini-computers and the digital Fast Fourier Transformation (FFT) spectrum analyzer in the early 1970's. In this paper, the damage in ferrocement tank is detected experimentally by changing in its dynamic parameters due to two damages that were manufactured in its wall. Also in the current paper, theoretical models using ANSYS finite element software were developed to find the modal parameters of the healthy and damage tank. The current results showed that the theoretical models give accurate results in comparing with the theoretical results. Also the experimental modal analysis is quick, easy and inexpensive method to detect the damage in the ferrocement tank.

Research paper thumbnail of Seismic response of a full-scale wind turbine tower using experimental and numerical modal analysis

International Journal of Advanced Structural Engineering, 2016

Wind turbine technology has developed tremendously over the past years. In Egypt, the Zafarana wi... more Wind turbine technology has developed tremendously over the past years. In Egypt, the Zafarana wind farm is currently generating at a capacity of 517 MW, making it one of the largest onshore wind farms in the world. It is located in an active seismic zone along the west side of the Gulf of Suez. Accordingly, seismic risk assessment is demanded for studying the structural integrity of wind towers under expected seismic hazard events. In the context of ongoing joint Egypt-US research project ''Seismic Risk Assessment of Wind Turbine Towers in Zafarana wind Farm Egypt'' (Project ID: 4588), this paper describes the dynamic performance investigation of an existing Nordex N43 wind turbine tower. Both experimental and numerical work are illustrated explaining the methodology adopted to investigate the dynamic behavior of the tower under seismic load. Field dynamic testing of the full-scale tower was performed using ambient vibration techniques (AVT). Both frequency domain and time domain methods were utilized to identify the actual dynamic properties of the tower as built in the site. Mainly, the natural frequencies, their corresponding mode shapes and damping ratios of the tower were successfully identified using AVT. A vibration-based finite element model (FEM) was constructed using ANSYS V.12 software. The numerical and experimental results of modal analysis were both compared for matching purpose. Using different simulation considerations, the initial FEM was updated to finally match the experimental results with good agreement. Using the final updated FEM, the response of the tower under the AQABA earthquake excitation was investigated. Time history analysis was conducted to define the seismic response of the tower in terms of the structural stresses and displacements. This work is considered as one of the pioneer structural studies of the wind turbine towers in Egypt. Identification of the actual dynamic properties of the existing tower was successfully performed based on AVT. Using advanced techniques in both the field testing and the numerical investigations produced reliable FEM specific for the tested tower, which can be further used in more advanced structural investigations for improving the design of such special structures. Keywords Wind turbine tower Á Ambient vibration test Á Zafarana wind farm Á Time history analysis Á Seismic response

Research paper thumbnail of Structural Performance of Strengthened Steel Girders with Web Openings under Shear Forces

The use of Steel Beams with Web Openings such as industrial and multistoried buildings has evicte... more The use of Steel Beams with Web Openings such as industrial and multistoried buildings has evicted to be wide in recent times. The existing study goals to examine the structural performance of steel beams with web openings in the shear zones and detect the chance of using carbon fiber reinforced polymer epoxy laminates as a composite material for the strengthening process. The shapes, numbers of web openings where the openings area is constant for all beams, places and thickness of composite material for strengthening beams were the main parameters. The behavior of ten steel beams which contain beams with opening, beams without openings and beams strengthened with different forms were specified by a Finite Element Model. An experimental program performed in the current work for four beams; control beam where there is without openings and number of three beams with web openings. The finite element results display a good agreement with the analogical values detected in the experiments...

Research paper thumbnail of Structural performance of ferrocement beams reinforced with composite materials

Structural Engineering and Mechanics, 2014

An experimental program was designed in the current work to examine the structural behavior of fe... more An experimental program was designed in the current work to examine the structural behavior of ferrocement beams reinforced with composite materials under three point loadings up to failure. The experimental program comprised casting and testing of twelve ferrocement beams having the dimensions of 120 mm width, 200 mm depth and 1600 mm length. The twelve beams were different in the type of reinforcements; steel bars, traditional wire meshes (welded and expanded wire meshes) and composite materials (fiberglass wire meshes and polypropylene wire meshes). The flexural performances of the all tested beams in terms of strength, ductility, cracking behavior and energy absorption were investigated. Also all the tested beams were simulated using ANSYS program. The results of the experimental tests concluded that the beam with fiber glass meshes gives the lowest first crack load and ultimate load. The ferrocement beam reinforced with four layers of welded wire meshes has better structural behavior than those beams reinforced with other types of wire meshes. Also the beams reinforced with metal wire meshes give smaller cracks width in comparing with those reinforced with non-metal wire meshes. Also the Finite Element (FE) simulations gave good results comparing with the experimental results.

Research paper thumbnail of FE Simulation of Transmission Tower

Advances in Civil Engineering, 2014

The vital components of the transmission line are the electrical transmission towers. They are co... more The vital components of the transmission line are the electrical transmission towers. They are commonly used to support the phase conductors and shield wires of a transmission line. Also the accurate prediction of tower failure is very important for the reliability and safety of the transmission system. The current research describes nonlinear FE models of predicting the transmission tower failure. In the current FE simulations, the eccentricity and the joint effect of the tower were considered. The current models have been calibrated with results from previous full-scale tower tests and numerical models with good accuracy in terms of both the failure load and the failure mode.

Research paper thumbnail of Retrofitting Notch Damaged Box Steel Beams with Composite Materials

An experimental program was designed to investigate the structural behavior of retrofitted notch ... more An experimental program was designed to investigate the structural behavior of retrofitted notch damaged box steel beams using Fiber-Reinforced Polymer (FRP) under flexure up to failure. The experimental program included twelve box steel specimens; one intact specimen, one notched specimen and ten notches damaged specimen and repaired with FRP sheets. All the tested beams have 1000 mm length. The notches specimens were notched at the tension flanges at 400 mm distance from the beam edge to simulate a localized and non-uniformly distributed deterioration along the beam length. The beams were repaired by bonding the FRP to the tension flange only, and the sheets were wrapped to cover a part of the two webs for the two beam halves or for the half of the beam that includes the notch with different heights. All the tested beams were simulated using a Finite Element (FE) program, and the FE model gives good results in comparison with the test results. The presented results indicate that wrapping CFRP sheet around the two webs for the half of the beam that includes the notch only gives an acceptable structural performance in comparing with wrapping CFRP sheet around the two webs for two halves of the beam and in this beam, the difference in the deflections of the two halves of the beam at the ultimate load does not increase than 3.2%.

Research paper thumbnail of Structural behavior of recycled aggregates concrete filled steel tubular columns A R T I C L E I N F O

A B S T R A C T This paper presents an experimental and numerical investigation to determine the ... more A B S T R A C T This paper presents an experimental and numerical investigation to determine the behavior of steel tubular columns filled with recycled aggregates concrete up to failure under constant axial compression loads. The experimental program included two steel tube columns, four recycled concrete columns and eight composite columns filled with different types of recycled coarse aggregates (granite and ceramic). Different percentages of recycled coarse aggregates: 0, 25 and 50 of the percentage of the coarse aggregates (dolomite) were used. The results of the numerical model that was employed by the finite element program, ANSYS, were compared with the experimental results. The results of the experimental study and the finite element analysis were compared with the design equations using different national building codes: AISC1999, AISC2005 and EC4. The results indicated that the recycled aggregates concrete infill columns have slightly lower but comparable ultimate capacities compared with the specimens filled with normal concrete.

Research paper thumbnail of Dynamic Behavior of A Full-Scale Wind Turbine Tower Under Seismic Loading

—This paper presents the dynamic investigation of an existing wind turbine tower. Both experiment... more —This paper presents the dynamic investigation of an existing wind turbine tower. Both experimental and numerical analyses were performed to assess the structural response of the tower under seismic load. Field ambient vibration test was applied to identify the actual dynamic properties experimentally. A vibration based finite element model was built in ANSYS to conduct the seismic response analysis. The tower shown to survive moderate earthquakes as it is located in Zafarana wind farm in Egypt, a zone lies by the red sea known for its historical seismic activity.

Research paper thumbnail of Seismic response of a full-scale wind turbine tower using experimental and numerical modal analysis

Wind turbine technology has developed tremendously over the past years. In Egypt, the Zafarana wi... more Wind turbine technology has developed tremendously over the past years. In Egypt, the Zafarana
wind farm is currently generating at a capacity of 517 MW, making it one of the largest onshore wind farms in the world. It is located in an active seismic zone along the west side of the Gulf of Suez. Accordingly, seismic risk assessment is demanded for studying the structural integrity of wind towers under expected seismic hazard events. In the context of ongoing joint Egypt–US research project ‘‘Seismic Risk Assessment of Wind Turbine Towers in Zafarana wind Farm Egypt’’ (Project ID: 4588), this paper describes the dynamic performance investigation of an existing Nordex N43 wind turbine tower. Both experimental and numerical work are illustrated explaining the methodology adopted to investigate the dynamic behavior of the tower under seismic load. Field dynamic testing of the full-scale tower was performed using ambient vibration techniques (AVT). Both frequency domain and time domain methods were utilized to identify the actual dynamic properties of the tower as built in the site. Mainly, the natural frequencies, their corresponding mode shapes and damping ratios of the tower were successfully identified using AVT. A vibration-based finite element model (FEM) was constructed using ANSYS V.12 software. The numerical and experimental results of modal analysis were both compared for matching purpose. Using different simulation considerations, the initial FEM was updated to finally match the experimental results with good agreement. Using the final updated FEM, the response of the tower under the AQABA earthquake excitation was investigated. Time history analysis was conducted to define the seismic response of the tower in terms of the structural stresses and displacements. This work is considered as one of the pioneer structural studies of the wind turbine towers in Egypt. Identification of the actual dynamic properties of the existing tower was successfully performed based on AVT. Using advanced techniques in both the field testing and the numerical investigations produced reliable FEM specific for the tested tower, which can be further used in more advanced structural investigations for improving the design of such special structures.

Research paper thumbnail of Response of Reinforced Concrete Box Girders Strengthened with composite Materials

Research Square (Research Square), May 25, 2022

The current research includes the results of a practical and numerical program to determine the b... more The current research includes the results of a practical and numerical program to determine the best way to enhance the behavior of RC box beams where the practical program relied on casting and testing 15 samples under bending. The factors that were taken into account were the use of ferrocement laminate at the tensile side or in the form of a U-shape, the number of meshes, as well as its type (welded or expanded) and the use of composite materials (CFRP, GFR). For composite materials, the strengthening was carried out in different ways, where it was applied at the tensile side only and wrapping the composite material around the web like a U-shape along the total beam's length or as strips with different sizes and spacing. The outcomes showed that the girders strengthened by 4 GFRP and 1 CFRP layers as a U-shaped have the highest service load and ultimate load.

Research paper thumbnail of Behavior of reinforced concrete stair slabs strengthened with steel plates and near surface mounted steel bars

Research paper thumbnail of Behavior of reinforced concrete ring beams strengthened with sustainable materials

Research paper thumbnail of Enhancing the behavior of reinforced concrete box girders under Two-point Loading: Numerical and experimental investigations

Research paper thumbnail of Seismic response of a full-scale wind turbine tower using experimental and numerical modal analysis

International Journal of Advanced Structural Engineering

Wind turbine technology has developed tremendously over the past years. In Egypt, the Zafarana wi... more Wind turbine technology has developed tremendously over the past years. In Egypt, the Zafarana wind farm is currently generating at a capacity of 517 MW, making it one of the largest onshore wind farms in the world. It is located in an active seismic zone along the west side of the Gulf of Suez. Accordingly, seismic risk assessment is demanded for studying the structural integrity of wind towers under expected seismic hazard events. In the context of ongoing joint Egypt-US research project ''Seismic Risk Assessment of Wind Turbine Towers in Zafarana wind Farm Egypt'' (Project ID: 4588), this paper describes the dynamic performance investigation of an existing Nordex N43 wind turbine tower. Both experimental and numerical work are illustrated explaining the methodology adopted to investigate the dynamic behavior of the tower under seismic load. Field dynamic testing of the full-scale tower was performed using ambient vibration techniques (AVT). Both frequency domain and time domain methods were utilized to identify the actual dynamic properties of the tower as built in the site. Mainly, the natural frequencies, their corresponding mode shapes and damping ratios of the tower were successfully identified using AVT. A vibration-based finite element model (FEM) was constructed using ANSYS V.12 software. The numerical and experimental results of modal analysis were both compared for matching purpose. Using different simulation considerations, the initial FEM was updated to finally match the experimental results with good agreement. Using the final updated FEM, the response of the tower under the AQABA earthquake excitation was investigated. Time history analysis was conducted to define the seismic response of the tower in terms of the structural stresses and displacements. This work is considered as one of the pioneer structural studies of the wind turbine towers in Egypt. Identification of the actual dynamic properties of the existing tower was successfully performed based on AVT. Using advanced techniques in both the field testing and the numerical investigations produced reliable FEM specific for the tested tower, which can be further used in more advanced structural investigations for improving the design of such special structures. Keywords Wind turbine tower Á Ambient vibration test Á Zafarana wind farm Á Time history analysis Á Seismic response

Research paper thumbnail of Ferrocement composite columns incorporating hollow core filled with lightweight concrete

Research paper thumbnail of Experimental and FE simulations of ferrocement columnsincorporating composite materials

Structural Engineering and Mechanics, 2017

In this study, 10 ferroconcrete concrete (FC) beams with lightweight cores reinforced with welded... more In this study, 10 ferroconcrete concrete (FC) beams with lightweight cores reinforced with welded steel mesh as a shear reinforcement were evaluated under three-point bending tests along with two conventionally normal-weight concrete (NWC) beams. Expanded polystyrene and lightweight aerated autoclaved brick wastes were used to create lightweight core concrete. The main factors include the type of lightweight concrete used for the core, beam concrete type, the form and number of holes, the existing steel mesh fabric, the hollow, and the hole placement. This study was done on the tested beams' ductility index, failure modes, first cracking loads and associated deflections, and ultimate loads besides corresponding deflections. Experimental results showed that the use of FC, various filling materials, and welded steel meshes in place of traditional stirrups enhanced the ultimate load by 36.6-107.3%, the ultimate deflection by 6-272%, and the ductility by 89-1155% when referenced to a control NWC beam. When the holing ratio increased from 10 to 20%, the ductility of FC beams was enhanced by 307.7%. Proposed equations were developed to predict the ultimate load and bending moment capacity of FC beams while taking into account the compressive strength of the beam body and filling material, the holing ratio, the tensile reinforcement ratio, and the volume fraction of the steel mesh. Highlights • This study is focusing on structural performance of ferrocement beams with lightweight cores reinforced with steel mesh fabric as a shear reinforcement. • Lightweight core concrete with steel mesh fabric reinforcement was made either using lightweight aerated autoclaved brick aggregate (LAABA) or expanded polystyrene (EP). • Impact of core lightweight concrete type, shape/number of holes, existing steel mesh fabric, concrete type, existing hollow core, positioning of hole on structural performance of the beams were performed. • Structural performance factors such ductility index, failure mechanism, first cracking loads and deflections and ultimate loads and deflections were studied.

Research paper thumbnail of Structural Performance of Ferrocement Beams Incorporating Longitudinal Hole Filled with Lightweight Concrete

International Journal of Concrete Structures and Materials

In this study, 10 ferroconcrete concrete (FC) beams with lightweight cores reinforced with welded... more In this study, 10 ferroconcrete concrete (FC) beams with lightweight cores reinforced with welded steel mesh as a shear reinforcement were evaluated under three-point bending tests along with two conventionally normal-weight concrete (NWC) beams. Expanded polystyrene and lightweight aerated autoclaved brick wastes were used to create lightweight core concrete. The main factors include the type of lightweight concrete used for the core, beam concrete type, the form and number of holes, the existing steel mesh fabric, the hollow, and the hole placement. This study was done on the tested beams' ductility index, failure modes, first cracking loads and associated deflections, and ultimate loads besides corresponding deflections. Experimental results showed that the use of FC, various filling materials, and welded steel meshes in place of traditional stirrups enhanced the ultimate load by 36.6–107.3%, the ultimate deflection by 6–272%, and the ductility by 89–1155% when referenced to ...

Research paper thumbnail of Dynamic Behavior of A Full Scale Wind Turbine Tower Under Seismic Loading

Fifth International Conference On Advances in Civil, Structural and Mechanical Engineering -ACSM 2016, 2016

This paper presents the dynamic investigation of an existing wind turbine tower. Both experimenta... more This paper presents the dynamic investigation of an existing wind turbine tower. Both experimental and numerical analyses were performed to assess the structural response of the tower under seismic load. Field ambient vibration test was applied to identify the actual dynamic properties experimentally. A vibration based finite element model was built in ANSYS to conduct the seismic response analysis. The tower shown to survive moderate earthquakes as it is located in Zafarana wind farm in Egypt, a zone lies by the red sea known for its historical seismic activity.

Research paper thumbnail of Retrofitting Notch Damaged Box Steel Beams with Composite Materials

KSCE Journal of Civil Engineering, 2017

An experimental program was designed to investigate the structural behavior of retrofitted notch ... more An experimental program was designed to investigate the structural behavior of retrofitted notch damaged box steel beams using Fiber-Reinforced Polymer (FRP) under flexure up to failure. The experimental program included twelve box steel specimens; one intact specimen, one notched specimen and ten notches damaged specimen and repaired with FRP sheets. All the tested beams have 1000 mm length. The notches specimens were notched at the tension flanges at 400 mm distance from the beam edge to simulate a localized and non-uniformly distributed deterioration along the beam length. The beams were repaired by bonding the FRP to the tension flange only, and the sheets were wrapped to cover a part of the two webs for the two beam halves or for the half of the beam that includes the notch with different heights. All the tested beams were simulated using a Finite Element (FE) program, and the FE model gives good results in comparison with the test results. The presented results indicate that wrapping CFRP sheet around the two webs for the half of the beam that includes the notch only gives an acceptable structural performance in comparing with wrapping CFRP sheet around the two webs for two halves of the beam and in this beam, the difference in the deflections of the two halves of the beam at the ultimate load does not increase than 3.2%.

Research paper thumbnail of Structural behavior of recycled aggregates concrete filled steel tubular columns

Challenge Journal of Concrete Research Letters, 2017

This paper presents an experimental and numerical investigation to determine the behavior of stee... more This paper presents an experimental and numerical investigation to determine the behavior of steel tubular columns filled with recycled aggregates concrete up to failure under constant axial compression loads. The experimental program included two steel tube columns, four recycled concrete columns and eight composite columns filled with different types of recycled coarse aggregates (granite and ceramic). Different percentages of recycled coarse aggregates: 0, 25 and 50 of the percentage of the coarse aggregates (dolomite) were used. The results of the numerical model that was employed by the finite element program, ANSYS, were compared with the experimental results. The results of the experimental study and the finite element analysis were compared with the design equations using different national building codes: AISC1999, AISC2005 and EC4. The results indicated that the recycled aggregates concrete infill columns have slightly lower but comparable ultimate capacities compared with ...

Research paper thumbnail of Damage Detection of Ferrocement Tanks Using Experimental Modal Analysis and Finite Element Analysis

Concrete Research Letters, Sep 13, 2013

In the recent years, structural health monitoring for civil structures using experimental modal a... more In the recent years, structural health monitoring for civil structures using experimental modal analysis has been developed. Experimental modal analysis is the process of determining the dynamic parameters (frequencies, damping factors, modal vectors and modal scaling) of a linear, time invariant system by way of an experimental approach. It began in 1940's in aircraft then it used in civil structures since the advent of the digital mini-computers and the digital Fast Fourier Transformation (FFT) spectrum analyzer in the early 1970's. In this paper, the damage in ferrocement tank is detected experimentally by changing in its dynamic parameters due to two damages that were manufactured in its wall. Also in the current paper, theoretical models using ANSYS finite element software were developed to find the modal parameters of the healthy and damage tank. The current results showed that the theoretical models give accurate results in comparing with the theoretical results. Also the experimental modal analysis is quick, easy and inexpensive method to detect the damage in the ferrocement tank.

Research paper thumbnail of Seismic response of a full-scale wind turbine tower using experimental and numerical modal analysis

International Journal of Advanced Structural Engineering, 2016

Wind turbine technology has developed tremendously over the past years. In Egypt, the Zafarana wi... more Wind turbine technology has developed tremendously over the past years. In Egypt, the Zafarana wind farm is currently generating at a capacity of 517 MW, making it one of the largest onshore wind farms in the world. It is located in an active seismic zone along the west side of the Gulf of Suez. Accordingly, seismic risk assessment is demanded for studying the structural integrity of wind towers under expected seismic hazard events. In the context of ongoing joint Egypt-US research project ''Seismic Risk Assessment of Wind Turbine Towers in Zafarana wind Farm Egypt'' (Project ID: 4588), this paper describes the dynamic performance investigation of an existing Nordex N43 wind turbine tower. Both experimental and numerical work are illustrated explaining the methodology adopted to investigate the dynamic behavior of the tower under seismic load. Field dynamic testing of the full-scale tower was performed using ambient vibration techniques (AVT). Both frequency domain and time domain methods were utilized to identify the actual dynamic properties of the tower as built in the site. Mainly, the natural frequencies, their corresponding mode shapes and damping ratios of the tower were successfully identified using AVT. A vibration-based finite element model (FEM) was constructed using ANSYS V.12 software. The numerical and experimental results of modal analysis were both compared for matching purpose. Using different simulation considerations, the initial FEM was updated to finally match the experimental results with good agreement. Using the final updated FEM, the response of the tower under the AQABA earthquake excitation was investigated. Time history analysis was conducted to define the seismic response of the tower in terms of the structural stresses and displacements. This work is considered as one of the pioneer structural studies of the wind turbine towers in Egypt. Identification of the actual dynamic properties of the existing tower was successfully performed based on AVT. Using advanced techniques in both the field testing and the numerical investigations produced reliable FEM specific for the tested tower, which can be further used in more advanced structural investigations for improving the design of such special structures. Keywords Wind turbine tower Á Ambient vibration test Á Zafarana wind farm Á Time history analysis Á Seismic response

Research paper thumbnail of Structural Performance of Strengthened Steel Girders with Web Openings under Shear Forces

The use of Steel Beams with Web Openings such as industrial and multistoried buildings has evicte... more The use of Steel Beams with Web Openings such as industrial and multistoried buildings has evicted to be wide in recent times. The existing study goals to examine the structural performance of steel beams with web openings in the shear zones and detect the chance of using carbon fiber reinforced polymer epoxy laminates as a composite material for the strengthening process. The shapes, numbers of web openings where the openings area is constant for all beams, places and thickness of composite material for strengthening beams were the main parameters. The behavior of ten steel beams which contain beams with opening, beams without openings and beams strengthened with different forms were specified by a Finite Element Model. An experimental program performed in the current work for four beams; control beam where there is without openings and number of three beams with web openings. The finite element results display a good agreement with the analogical values detected in the experiments...

Research paper thumbnail of Structural performance of ferrocement beams reinforced with composite materials

Structural Engineering and Mechanics, 2014

An experimental program was designed in the current work to examine the structural behavior of fe... more An experimental program was designed in the current work to examine the structural behavior of ferrocement beams reinforced with composite materials under three point loadings up to failure. The experimental program comprised casting and testing of twelve ferrocement beams having the dimensions of 120 mm width, 200 mm depth and 1600 mm length. The twelve beams were different in the type of reinforcements; steel bars, traditional wire meshes (welded and expanded wire meshes) and composite materials (fiberglass wire meshes and polypropylene wire meshes). The flexural performances of the all tested beams in terms of strength, ductility, cracking behavior and energy absorption were investigated. Also all the tested beams were simulated using ANSYS program. The results of the experimental tests concluded that the beam with fiber glass meshes gives the lowest first crack load and ultimate load. The ferrocement beam reinforced with four layers of welded wire meshes has better structural behavior than those beams reinforced with other types of wire meshes. Also the beams reinforced with metal wire meshes give smaller cracks width in comparing with those reinforced with non-metal wire meshes. Also the Finite Element (FE) simulations gave good results comparing with the experimental results.

Research paper thumbnail of FE Simulation of Transmission Tower

Advances in Civil Engineering, 2014

The vital components of the transmission line are the electrical transmission towers. They are co... more The vital components of the transmission line are the electrical transmission towers. They are commonly used to support the phase conductors and shield wires of a transmission line. Also the accurate prediction of tower failure is very important for the reliability and safety of the transmission system. The current research describes nonlinear FE models of predicting the transmission tower failure. In the current FE simulations, the eccentricity and the joint effect of the tower were considered. The current models have been calibrated with results from previous full-scale tower tests and numerical models with good accuracy in terms of both the failure load and the failure mode.

Research paper thumbnail of Retrofitting Notch Damaged Box Steel Beams with Composite Materials

An experimental program was designed to investigate the structural behavior of retrofitted notch ... more An experimental program was designed to investigate the structural behavior of retrofitted notch damaged box steel beams using Fiber-Reinforced Polymer (FRP) under flexure up to failure. The experimental program included twelve box steel specimens; one intact specimen, one notched specimen and ten notches damaged specimen and repaired with FRP sheets. All the tested beams have 1000 mm length. The notches specimens were notched at the tension flanges at 400 mm distance from the beam edge to simulate a localized and non-uniformly distributed deterioration along the beam length. The beams were repaired by bonding the FRP to the tension flange only, and the sheets were wrapped to cover a part of the two webs for the two beam halves or for the half of the beam that includes the notch with different heights. All the tested beams were simulated using a Finite Element (FE) program, and the FE model gives good results in comparison with the test results. The presented results indicate that wrapping CFRP sheet around the two webs for the half of the beam that includes the notch only gives an acceptable structural performance in comparing with wrapping CFRP sheet around the two webs for two halves of the beam and in this beam, the difference in the deflections of the two halves of the beam at the ultimate load does not increase than 3.2%.

Research paper thumbnail of Structural behavior of recycled aggregates concrete filled steel tubular columns A R T I C L E I N F O

A B S T R A C T This paper presents an experimental and numerical investigation to determine the ... more A B S T R A C T This paper presents an experimental and numerical investigation to determine the behavior of steel tubular columns filled with recycled aggregates concrete up to failure under constant axial compression loads. The experimental program included two steel tube columns, four recycled concrete columns and eight composite columns filled with different types of recycled coarse aggregates (granite and ceramic). Different percentages of recycled coarse aggregates: 0, 25 and 50 of the percentage of the coarse aggregates (dolomite) were used. The results of the numerical model that was employed by the finite element program, ANSYS, were compared with the experimental results. The results of the experimental study and the finite element analysis were compared with the design equations using different national building codes: AISC1999, AISC2005 and EC4. The results indicated that the recycled aggregates concrete infill columns have slightly lower but comparable ultimate capacities compared with the specimens filled with normal concrete.

Research paper thumbnail of Dynamic Behavior of A Full-Scale Wind Turbine Tower Under Seismic Loading

—This paper presents the dynamic investigation of an existing wind turbine tower. Both experiment... more —This paper presents the dynamic investigation of an existing wind turbine tower. Both experimental and numerical analyses were performed to assess the structural response of the tower under seismic load. Field ambient vibration test was applied to identify the actual dynamic properties experimentally. A vibration based finite element model was built in ANSYS to conduct the seismic response analysis. The tower shown to survive moderate earthquakes as it is located in Zafarana wind farm in Egypt, a zone lies by the red sea known for its historical seismic activity.

Research paper thumbnail of Seismic response of a full-scale wind turbine tower using experimental and numerical modal analysis

Wind turbine technology has developed tremendously over the past years. In Egypt, the Zafarana wi... more Wind turbine technology has developed tremendously over the past years. In Egypt, the Zafarana
wind farm is currently generating at a capacity of 517 MW, making it one of the largest onshore wind farms in the world. It is located in an active seismic zone along the west side of the Gulf of Suez. Accordingly, seismic risk assessment is demanded for studying the structural integrity of wind towers under expected seismic hazard events. In the context of ongoing joint Egypt–US research project ‘‘Seismic Risk Assessment of Wind Turbine Towers in Zafarana wind Farm Egypt’’ (Project ID: 4588), this paper describes the dynamic performance investigation of an existing Nordex N43 wind turbine tower. Both experimental and numerical work are illustrated explaining the methodology adopted to investigate the dynamic behavior of the tower under seismic load. Field dynamic testing of the full-scale tower was performed using ambient vibration techniques (AVT). Both frequency domain and time domain methods were utilized to identify the actual dynamic properties of the tower as built in the site. Mainly, the natural frequencies, their corresponding mode shapes and damping ratios of the tower were successfully identified using AVT. A vibration-based finite element model (FEM) was constructed using ANSYS V.12 software. The numerical and experimental results of modal analysis were both compared for matching purpose. Using different simulation considerations, the initial FEM was updated to finally match the experimental results with good agreement. Using the final updated FEM, the response of the tower under the AQABA earthquake excitation was investigated. Time history analysis was conducted to define the seismic response of the tower in terms of the structural stresses and displacements. This work is considered as one of the pioneer structural studies of the wind turbine towers in Egypt. Identification of the actual dynamic properties of the existing tower was successfully performed based on AVT. Using advanced techniques in both the field testing and the numerical investigations produced reliable FEM specific for the tested tower, which can be further used in more advanced structural investigations for improving the design of such special structures.