International Journal of Conservation Science, 2013
The understanding of the geotechnical problems and failure mechanisms of stone structures of Saka... more The understanding of the geotechnical problems and failure mechanisms of stone structures of Sakakini palace (1897 AC) entails a comprehensive study on the mechanical behavior of the stones and other construction materials. In addition to micro analysis, geological and geomorphologic interests, several investigations on stone deterioration and engineering geology were performed. First phase included more advanced techniques, which provided additional information on particular aspects of site deterioration and it included laser analysis (LIBS), electron probe micro analysis, micro XRD and XRF analyses, scanning electron microscope analysis coupled with EDX probing, transmission electron microscopy and grain size distribution analysis, permeability and pore size distribution of stone, mortars, core binders and other construction materials. Second phase included the determination of mechanical properties of building stones, such as compressive strength, modulus of elasticity, tensile s...
ABSTRACT A three-dimensional numerical model has been proposed of the central Rotunda of the cata... more ABSTRACT A three-dimensional numerical model has been proposed of the central Rotunda of the catacombs of Kom El-Shoqafa with its six supporting rock pillars, excavated in sandy oolitic limestone deposit. The model was based on a 3D realistic simulation of the problem geometry. The required input for the analysis (strength and deformability of the rock materials) was derived from laboratory tests and empirical assessments. The rock mass in general is normally widely jointed (> 1 m). In the analysis it is considered as an un-jointed homogeneous medium with low strength. Where 2D analysis fails to model properly the column behaviour, we use 3D modeling to evaluate the stress state in the supporting rock pillars of the excavated Rotunda, taking into account their 3D arrangement.. The results of the numerical analysis on the central supporting Rotunda show that some surface subsidence was induced during excavation of the catacombs. In particular, the displacement developed at the surface above the Rotunda reaches a maximum of 3 mm. This numerical result corroborates the observed displacements in the underground structures and the surface subsidence. The first part of this paper presents a comprehensive geotechnical survey undertaken in the archaeological site, comprising geophysical ambient noise measurements along with field and short-and long-term laboratory experiments, in order to define the physical, mechanical and dynamic properties of the soils and soft rock materials. The second part presents the main results of the detailed 3D numerical analysis of these underground monuments, using an advanced soil-rock elastoplastic modeling
One of the most durable building materials, stone has been used throughout history to build build... more One of the most durable building materials, stone has been used throughout history to build buildings. In particular, marble is the most common material in historical structures. For thousands of years, these materials have been valued for their beauty and versatility. Despite the permanent aura, marble can suffer from wear and tear. As a result of increased urbanization today in Rashid city, a high level of groundwater, salt accumulation and pollutions, marble degradation is occurring much faster than in the past. Accumulation of dust, cracked construction, spelling, and loss of structural integrity are among the problems affecting marble structures. There are many sources of marble deterioration, especially in the city of Rashid. Damage occurs through physical, chemical, and environmental weathering factors, air pollution, and soiling build-up. More damage can occur through corrosion, as a result of movement in marble (thermal expansion / shrinkage), damaged or broken impact point...
Present study summarizes an overview on the available experimental and practical data and results... more Present study summarizes an overview on the available experimental and practical data and results from laboratory testing (ungrouted and grouted) three leaf masonry wallettes in compression and in diagonal compression. On the basis of the experimental results, (A) the structural behavior of the multiple leaf-masonry walls studied in details (b) the parameters that affect the behavior of ungrouted masonry are detected and commented upon, and (c) the behavior of grouted masonry studied in details. Particularly attention to be paid to large walls whose construction may comprise different kinds of materials. Such walls include cavity walls; rubble filled masonry walls and veneered brick walls which have poor quality core. Not only may the interior of the wall be less capable of carrying load but movement of the core material may also be a source of new stresses. As the experimental results show that the key parameter for the improvement of the mechanical properties of masonry is not the...
Geotechnical modeling of complex soil problems requires an advanced 3D discretization and a sophi... more Geotechnical modeling of complex soil problems requires an advanced 3D discretization and a sophisticated soil models. The aim of the present study is to accurately analysis the geotechnical and induced structural failure mechanisms observed in the field and experimental studies. In order to provide a contribution to quantify the stress and deformation analysis and settlement of soft clay subsoil, a geotechnical analytical model is presented in details. The study presents an attempt of a PLAXIS 3D FE analysis model to simulate the subsoil problems, deformation and stress analysis of the multi-layer masonry structures of Abu Serga church in Cairo, Egypt which is loaded in plane. Advanced soil plastic modeling has been used throughout the different phases of the numerical analysis. The numerical and experimental analysis allowed us to define the pathology of this unique architectural heritage and to estimate the subsoil deformation as well as the stress–strain analysis of its superstructure, also to define the ultimate load that they can survive under their present conditions. The results are discussed with respect to the stress–strain and volumetric behavior of the soil. Consequently it can be concluded that modeling the behavior of subsoil soft clay underneath Abu Serga church by the Numerical analysis is suitable for understanding of the studied behavior of this kind of problematic soil.
The Valley of the Kings (KV) is a UNESCO world heritage site with more than thirty opened tombs. ... more The Valley of the Kings (KV) is a UNESCO world heritage site with more than thirty opened tombs. Since the first tombs were constructed, at least 24 historical flash flood events has been identified, each of which has been contributed to the destruction and deterioration of the tombs. Recently, most of these tombs have been damaged and inundated after 1994 flood. In order to understand the Geo-environmental impact mainly the past flash floods due to the intensive rainfall storm on the valley of kings and the long-term rock mass behavior under geostatic stresses in selected Horemheb tomb (KV57) and its impact on past failures and current stability, Remote sensing, GIS, LIDAR, 3D finite element stability analysis and rock mass quality assessments had been carried out using advanced methods and codes. Our work provides environmental satellite space views via landviewer Erath Observation System (EOS) Platform with passive and active sensors which include the Normalized Difference Vegeta...
Alexandria is one of the Mediterranean UNESCO World Heritage sites at risk from coastal flooding ... more Alexandria is one of the Mediterranean UNESCO World Heritage sites at risk from coastal flooding and erosion due to sea-level rise. The city’s position on the Mediterranean coast means it is especially vulnerable to rising sea levels. Alexandria is one of UNESCO sites in Egypt at risk from flooding. All the archaeological sites in the northern coast of Egypt are also said to be at risk from coastal erosion. The flood risk in Alexandria is expected to reach a tipping point by 2050. This research presents the numerical analysis of geotechnical and structural damage mechanism of Catacombs of Kom El-Shoqafa and El-Shatbi Necropolis; the sites have the lowest topography in Alexandria induced by the sea level rise and heavy rain due to the Climate Change, based on Finite Element PLAXIS Code. The purpose of the study was to investigate the behavior fully-saturated soft rock/ hard soil subjected to ground water intrusions. The main objective of this study is to very accurately record and an...
The Pyramids complex in Giza consists of three main pyramids in addition to the famous Sphinx and... more The Pyramids complex in Giza consists of three main pyramids in addition to the famous Sphinx and small queen's pyramids. Recently, the pyramids of Cheops (Khufu), Chephren (Khafre) and Mykerinos (Menkaure) on the Giza plateau have been threatened by a rising groundwater table resulting from water leakage from the suburbs irrigation canals, and mass urbanization surrounding the Giza pyramids. The pyramids at Giza suffer from a lot of Geo-environmental and structural problems. The main objectives of this study are (1) to assess the current status of the preservation of this unique and high valuable archaeological site, (2) to analyze the various actions that cause the destruction of the pyramid complex, in particular the weathering activities and strong seismic event, and (3) to determine the geochemical and engineering properties for construction materials using different types of tools and advanced analytical and diagnostic techniques. Structural stability analysis requires good assessment of present conditions of major materials used such as stones and structural mortar. The paper shows a thorough analysis of the current condition of the Great Pyramids at Giza. The work includes a discussion and analysis of the natural character and source of the pyramids building stones, geological context, damage survey, petrographic investigation, and physical and mechanical characterization of the stones and structural mortars, by means of laboratory and in situ testing. The results are displayed, described and analyzed in the paper in the context of potential threats to the monuments. The experimental study indicates the dependence of mechanical geological properties on the physical properties and the mineral composition of the studied building materials. The physical and petrographic characteristic of the stones are related. The modeling of properties indicates a reliable relationship between the various visible pores and uniaxial compression force parameters that can be applied to predict and characterize limestone elsewhere.
International Journal of Conservation Science, 2013
The understanding of the geotechnical problems and failure mechanisms of stone structures of Saka... more The understanding of the geotechnical problems and failure mechanisms of stone structures of Sakakini palace (1897 AC) entails a comprehensive study on the mechanical behavior of the stones and other construction materials. In addition to micro analysis, geological and geomorphologic interests, several investigations on stone deterioration and engineering geology were performed. First phase included more advanced techniques, which provided additional information on particular aspects of site deterioration and it included laser analysis (LIBS), electron probe micro analysis, micro XRD and XRF analyses, scanning electron microscope analysis coupled with EDX probing, transmission electron microscopy and grain size distribution analysis, permeability and pore size distribution of stone, mortars, core binders and other construction materials. Second phase included the determination of mechanical properties of building stones, such as compressive strength, modulus of elasticity, tensile s...
ABSTRACT A three-dimensional numerical model has been proposed of the central Rotunda of the cata... more ABSTRACT A three-dimensional numerical model has been proposed of the central Rotunda of the catacombs of Kom El-Shoqafa with its six supporting rock pillars, excavated in sandy oolitic limestone deposit. The model was based on a 3D realistic simulation of the problem geometry. The required input for the analysis (strength and deformability of the rock materials) was derived from laboratory tests and empirical assessments. The rock mass in general is normally widely jointed (> 1 m). In the analysis it is considered as an un-jointed homogeneous medium with low strength. Where 2D analysis fails to model properly the column behaviour, we use 3D modeling to evaluate the stress state in the supporting rock pillars of the excavated Rotunda, taking into account their 3D arrangement.. The results of the numerical analysis on the central supporting Rotunda show that some surface subsidence was induced during excavation of the catacombs. In particular, the displacement developed at the surface above the Rotunda reaches a maximum of 3 mm. This numerical result corroborates the observed displacements in the underground structures and the surface subsidence. The first part of this paper presents a comprehensive geotechnical survey undertaken in the archaeological site, comprising geophysical ambient noise measurements along with field and short-and long-term laboratory experiments, in order to define the physical, mechanical and dynamic properties of the soils and soft rock materials. The second part presents the main results of the detailed 3D numerical analysis of these underground monuments, using an advanced soil-rock elastoplastic modeling
One of the most durable building materials, stone has been used throughout history to build build... more One of the most durable building materials, stone has been used throughout history to build buildings. In particular, marble is the most common material in historical structures. For thousands of years, these materials have been valued for their beauty and versatility. Despite the permanent aura, marble can suffer from wear and tear. As a result of increased urbanization today in Rashid city, a high level of groundwater, salt accumulation and pollutions, marble degradation is occurring much faster than in the past. Accumulation of dust, cracked construction, spelling, and loss of structural integrity are among the problems affecting marble structures. There are many sources of marble deterioration, especially in the city of Rashid. Damage occurs through physical, chemical, and environmental weathering factors, air pollution, and soiling build-up. More damage can occur through corrosion, as a result of movement in marble (thermal expansion / shrinkage), damaged or broken impact point...
Present study summarizes an overview on the available experimental and practical data and results... more Present study summarizes an overview on the available experimental and practical data and results from laboratory testing (ungrouted and grouted) three leaf masonry wallettes in compression and in diagonal compression. On the basis of the experimental results, (A) the structural behavior of the multiple leaf-masonry walls studied in details (b) the parameters that affect the behavior of ungrouted masonry are detected and commented upon, and (c) the behavior of grouted masonry studied in details. Particularly attention to be paid to large walls whose construction may comprise different kinds of materials. Such walls include cavity walls; rubble filled masonry walls and veneered brick walls which have poor quality core. Not only may the interior of the wall be less capable of carrying load but movement of the core material may also be a source of new stresses. As the experimental results show that the key parameter for the improvement of the mechanical properties of masonry is not the...
Geotechnical modeling of complex soil problems requires an advanced 3D discretization and a sophi... more Geotechnical modeling of complex soil problems requires an advanced 3D discretization and a sophisticated soil models. The aim of the present study is to accurately analysis the geotechnical and induced structural failure mechanisms observed in the field and experimental studies. In order to provide a contribution to quantify the stress and deformation analysis and settlement of soft clay subsoil, a geotechnical analytical model is presented in details. The study presents an attempt of a PLAXIS 3D FE analysis model to simulate the subsoil problems, deformation and stress analysis of the multi-layer masonry structures of Abu Serga church in Cairo, Egypt which is loaded in plane. Advanced soil plastic modeling has been used throughout the different phases of the numerical analysis. The numerical and experimental analysis allowed us to define the pathology of this unique architectural heritage and to estimate the subsoil deformation as well as the stress–strain analysis of its superstructure, also to define the ultimate load that they can survive under their present conditions. The results are discussed with respect to the stress–strain and volumetric behavior of the soil. Consequently it can be concluded that modeling the behavior of subsoil soft clay underneath Abu Serga church by the Numerical analysis is suitable for understanding of the studied behavior of this kind of problematic soil.
The Valley of the Kings (KV) is a UNESCO world heritage site with more than thirty opened tombs. ... more The Valley of the Kings (KV) is a UNESCO world heritage site with more than thirty opened tombs. Since the first tombs were constructed, at least 24 historical flash flood events has been identified, each of which has been contributed to the destruction and deterioration of the tombs. Recently, most of these tombs have been damaged and inundated after 1994 flood. In order to understand the Geo-environmental impact mainly the past flash floods due to the intensive rainfall storm on the valley of kings and the long-term rock mass behavior under geostatic stresses in selected Horemheb tomb (KV57) and its impact on past failures and current stability, Remote sensing, GIS, LIDAR, 3D finite element stability analysis and rock mass quality assessments had been carried out using advanced methods and codes. Our work provides environmental satellite space views via landviewer Erath Observation System (EOS) Platform with passive and active sensors which include the Normalized Difference Vegeta...
Alexandria is one of the Mediterranean UNESCO World Heritage sites at risk from coastal flooding ... more Alexandria is one of the Mediterranean UNESCO World Heritage sites at risk from coastal flooding and erosion due to sea-level rise. The city’s position on the Mediterranean coast means it is especially vulnerable to rising sea levels. Alexandria is one of UNESCO sites in Egypt at risk from flooding. All the archaeological sites in the northern coast of Egypt are also said to be at risk from coastal erosion. The flood risk in Alexandria is expected to reach a tipping point by 2050. This research presents the numerical analysis of geotechnical and structural damage mechanism of Catacombs of Kom El-Shoqafa and El-Shatbi Necropolis; the sites have the lowest topography in Alexandria induced by the sea level rise and heavy rain due to the Climate Change, based on Finite Element PLAXIS Code. The purpose of the study was to investigate the behavior fully-saturated soft rock/ hard soil subjected to ground water intrusions. The main objective of this study is to very accurately record and an...
The Pyramids complex in Giza consists of three main pyramids in addition to the famous Sphinx and... more The Pyramids complex in Giza consists of three main pyramids in addition to the famous Sphinx and small queen's pyramids. Recently, the pyramids of Cheops (Khufu), Chephren (Khafre) and Mykerinos (Menkaure) on the Giza plateau have been threatened by a rising groundwater table resulting from water leakage from the suburbs irrigation canals, and mass urbanization surrounding the Giza pyramids. The pyramids at Giza suffer from a lot of Geo-environmental and structural problems. The main objectives of this study are (1) to assess the current status of the preservation of this unique and high valuable archaeological site, (2) to analyze the various actions that cause the destruction of the pyramid complex, in particular the weathering activities and strong seismic event, and (3) to determine the geochemical and engineering properties for construction materials using different types of tools and advanced analytical and diagnostic techniques. Structural stability analysis requires good assessment of present conditions of major materials used such as stones and structural mortar. The paper shows a thorough analysis of the current condition of the Great Pyramids at Giza. The work includes a discussion and analysis of the natural character and source of the pyramids building stones, geological context, damage survey, petrographic investigation, and physical and mechanical characterization of the stones and structural mortars, by means of laboratory and in situ testing. The results are displayed, described and analyzed in the paper in the context of potential threats to the monuments. The experimental study indicates the dependence of mechanical geological properties on the physical properties and the mineral composition of the studied building materials. The physical and petrographic characteristic of the stones are related. The modeling of properties indicates a reliable relationship between the various visible pores and uniaxial compression force parameters that can be applied to predict and characterize limestone elsewhere.
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