Should we care about what lies behind the surface of the cultural objects we value? If a feature ... more Should we care about what lies behind the surface of the cultural objects we value? If a feature is invisible to our senses, does its existence really deserves our attention and concern? Engineers like doctors obviously needs to know about anatomy, materials... bones and skin diseases. Their job is to preserve what society cherish and their mean of action requires this knowledge. But should said society be concerned only by failures of plastic surgery and facade cleaning, overlook the viscera and leaving their cure to the experts? And should these last understand their duty as not only caring for what people see but also caring for what they, themselves, have the privilege to see? These are the questions that the paper tries to develop and discuss.
This paper presents works done in March-July 2010, in the framework of the UNESCO programme” Capa... more This paper presents works done in March-July 2010, in the framework of the UNESCO programme” Capacity Building of Human Resources for Digital Documentation of World Heritage Sites Affected by 2006 War in Lebanon”. The aim of the project was to develop a methodological framework for the establishment of a Risk Preparedness Strategy (RPS) for the World Heritage Property of Baalbek (Fig. 1, 2;[1, 2]).
Nowadays, powerful methods are available for the calculation of structural safety values. These p... more Nowadays, powerful methods are available for the calculation of structural safety values. These permit to calculate the global failure probability of complex structures, relying on deterministic techniques able to determine the stability state for a prescribed set of parameters. The safety of arches is a typical example of new fields for these methods. Traditionally their stability is assessed using a deterministic approach, resulting in safety factors. To relate these safety factors to an absolute safety, requires a great deal of engineering judgement. In case of an existing arch, this judgement depends on a variety of uncertainties such as on the accuracy of the geometry measurements, the uncertainty on the material properties, support conditions and the constructional history of the structure. The proposed method calculates an absolute value for the global probability of failure at level III on the basis of the quantified uncertainties. Several techniques are available for the ca...
Although more and more computer-aided technologies are utilised or demonstrated on well-known mon... more Although more and more computer-aided technologies are utilised or demonstrated on well-known monuments or archaeological sites, there is at least for the professionals working in the field still some lack of clarity about their application. The main idea of our research project is to construct a prototype of a tool that tries to bring new technologies closer to the daily practice. It incorporates recent developments in computer vision and reverse engineering, while at the same time tries to answer the practical concerns from civil servants, architects, topographers, art-historians... who are responsible for the conservation of monuments or archaeological sites. The proposed system covers automatic correspondence analysis and point cloud manipulation to build up a textured 3D model. This model then acts as the central core of a multimedia data structure for the annotation, geometric and thematic interrogation and visualisation of the building or site being studied.
The hydrostatic levelling system (HLS) is a highly accurate technique to monitor differential ver... more The hydrostatic levelling system (HLS) is a highly accurate technique to monitor differential vertical settlements. The monitoring system is based on the principle of communicating vessels. The working principle is outlined and the results of two case studies are presented. These case studies not only focus on the use of the HLS as an accurate way of measuring differential settlements, but emphasize the relation with the structural behaviour of the building itself. Comparisons with more conventional geodetic systems are made. This provides objective information on which further options on strengthening and consolidation of the structure are based. d1 d2 d’1 d’2 d’12 Vessel 1 Vessel 2 Thermometer Data-acquisition Air water After vertical displacement Before vertical displacement Average water level Vessel 1 Vessel 2 530 Structural Analysis of Historical Constructions The readings range from 5000μm to 10000μm. Measurements are taken with the system frequency (about 33 Hz) and the resu...
ABSTRACT The present paper is concerned with the masonry webs of Gothic rib vaults built in the f... more ABSTRACT The present paper is concerned with the masonry webs of Gothic rib vaults built in the former Duchy of Brabant between the thirteenth and the sixteenth century. Contemporary documents providing information on vault geometry and construction are exceptional in Europe; they are non-existent or at best very fragmentary in Brabant. The buildings themselves are the principal source of information. Rib vaults are complex three-dimensional structures. In order to facilitate their understanding, four exemplary vaults were surveyed using a hybrid technique combining reflectorless total station measurements and digital photogrammetry. Four textured 3D computer models were built. After a short description of the surveying and modelling technique, the vaults are analysed and hypotheses are formulated on their construction technique. Emphasis is given to the close relationships existing between materials, geometry and construction techniques.
Virterf is a software combining recent developments in computer vision and reverse engineering ta... more Virterf is a software combining recent developments in computer vision and reverse engineering targeted for professionals working in the field of architectural conservation. The first part of the software aims at building relatively automatically a 3D model. In this article, focus is given to the second part, offering tools to qualify and query it. Information can be added, organised in themes or linked to the model. The resulting database with the software’s visualisation capacities facilitates comparison, synthesis and decision. Some reference concepts are first presented, the functionalities offered described and following first applications some possible development are discussed.
ABSTRACT The construction of the church dates back from 1220. During several subsequent building ... more ABSTRACT The construction of the church dates back from 1220. During several subsequent building phases, the wooden roofs in the central and side naves were replaced with masonry vaults, and flying buttresses were added. The structure itself is located on a former swamp, resulting in large differential settlements. In the past, restoration works took place. However, due to the excessive cracks observed, it was decided in 1963 to close the church for service, to remove the severely cracked masonry vaults of the side naves and to shore up the pillars of the main nave. Additionally, in 2000, the remaining flying buttresses were removed and replaced by tie-rods. The focus of this paper is on the structural understanding of this historical building, to determine the most appropriate strengthening and consolidation measures, respecting the authenticity of the building and preserving it for the future.
Should we care about what lies behind the surface of the cultural objects we value? If a feature ... more Should we care about what lies behind the surface of the cultural objects we value? If a feature is invisible to our senses, does its existence really deserves our attention and concern? Engineers like doctors obviously needs to know about anatomy, materials... bones and skin diseases. Their job is to preserve what society cherish and their mean of action requires this knowledge. But should said society be concerned only by failures of plastic surgery and facade cleaning, overlook the viscera and leaving their cure to the experts? And should these last understand their duty as not only caring for what people see but also caring for what they, themselves, have the privilege to see? These are the questions that the paper tries to develop and discuss.
This paper presents works done in March-July 2010, in the framework of the UNESCO programme” Capa... more This paper presents works done in March-July 2010, in the framework of the UNESCO programme” Capacity Building of Human Resources for Digital Documentation of World Heritage Sites Affected by 2006 War in Lebanon”. The aim of the project was to develop a methodological framework for the establishment of a Risk Preparedness Strategy (RPS) for the World Heritage Property of Baalbek (Fig. 1, 2;[1, 2]).
Nowadays, powerful methods are available for the calculation of structural safety values. These p... more Nowadays, powerful methods are available for the calculation of structural safety values. These permit to calculate the global failure probability of complex structures, relying on deterministic techniques able to determine the stability state for a prescribed set of parameters. The safety of arches is a typical example of new fields for these methods. Traditionally their stability is assessed using a deterministic approach, resulting in safety factors. To relate these safety factors to an absolute safety, requires a great deal of engineering judgement. In case of an existing arch, this judgement depends on a variety of uncertainties such as on the accuracy of the geometry measurements, the uncertainty on the material properties, support conditions and the constructional history of the structure. The proposed method calculates an absolute value for the global probability of failure at level III on the basis of the quantified uncertainties. Several techniques are available for the ca...
Although more and more computer-aided technologies are utilised or demonstrated on well-known mon... more Although more and more computer-aided technologies are utilised or demonstrated on well-known monuments or archaeological sites, there is at least for the professionals working in the field still some lack of clarity about their application. The main idea of our research project is to construct a prototype of a tool that tries to bring new technologies closer to the daily practice. It incorporates recent developments in computer vision and reverse engineering, while at the same time tries to answer the practical concerns from civil servants, architects, topographers, art-historians... who are responsible for the conservation of monuments or archaeological sites. The proposed system covers automatic correspondence analysis and point cloud manipulation to build up a textured 3D model. This model then acts as the central core of a multimedia data structure for the annotation, geometric and thematic interrogation and visualisation of the building or site being studied.
The hydrostatic levelling system (HLS) is a highly accurate technique to monitor differential ver... more The hydrostatic levelling system (HLS) is a highly accurate technique to monitor differential vertical settlements. The monitoring system is based on the principle of communicating vessels. The working principle is outlined and the results of two case studies are presented. These case studies not only focus on the use of the HLS as an accurate way of measuring differential settlements, but emphasize the relation with the structural behaviour of the building itself. Comparisons with more conventional geodetic systems are made. This provides objective information on which further options on strengthening and consolidation of the structure are based. d1 d2 d’1 d’2 d’12 Vessel 1 Vessel 2 Thermometer Data-acquisition Air water After vertical displacement Before vertical displacement Average water level Vessel 1 Vessel 2 530 Structural Analysis of Historical Constructions The readings range from 5000μm to 10000μm. Measurements are taken with the system frequency (about 33 Hz) and the resu...
ABSTRACT The present paper is concerned with the masonry webs of Gothic rib vaults built in the f... more ABSTRACT The present paper is concerned with the masonry webs of Gothic rib vaults built in the former Duchy of Brabant between the thirteenth and the sixteenth century. Contemporary documents providing information on vault geometry and construction are exceptional in Europe; they are non-existent or at best very fragmentary in Brabant. The buildings themselves are the principal source of information. Rib vaults are complex three-dimensional structures. In order to facilitate their understanding, four exemplary vaults were surveyed using a hybrid technique combining reflectorless total station measurements and digital photogrammetry. Four textured 3D computer models were built. After a short description of the surveying and modelling technique, the vaults are analysed and hypotheses are formulated on their construction technique. Emphasis is given to the close relationships existing between materials, geometry and construction techniques.
Virterf is a software combining recent developments in computer vision and reverse engineering ta... more Virterf is a software combining recent developments in computer vision and reverse engineering targeted for professionals working in the field of architectural conservation. The first part of the software aims at building relatively automatically a 3D model. In this article, focus is given to the second part, offering tools to qualify and query it. Information can be added, organised in themes or linked to the model. The resulting database with the software’s visualisation capacities facilitates comparison, synthesis and decision. Some reference concepts are first presented, the functionalities offered described and following first applications some possible development are discussed.
ABSTRACT The construction of the church dates back from 1220. During several subsequent building ... more ABSTRACT The construction of the church dates back from 1220. During several subsequent building phases, the wooden roofs in the central and side naves were replaced with masonry vaults, and flying buttresses were added. The structure itself is located on a former swamp, resulting in large differential settlements. In the past, restoration works took place. However, due to the excessive cracks observed, it was decided in 1963 to close the church for service, to remove the severely cracked masonry vaults of the side naves and to shore up the pillars of the main nave. Additionally, in 2000, the remaining flying buttresses were removed and replaced by tie-rods. The focus of this paper is on the structural understanding of this historical building, to determine the most appropriate strengthening and consolidation measures, respecting the authenticity of the building and preserving it for the future.
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Papers by Pierre Smars