Dr. Eng. Ahmed Elyamani

Historical structures and sites are among the important touristic attractions if they are properly managed and exploited. Rehabilitation is one of the important approaches of their re-use. This paper is throwing the light on one of the modern techniques in the rehabilitation which is the three dimensional (3D) virtual shows. The paper presents an inventory about three of these shows including: 3D cinema; 3D shows using projection maps and hologram. This new technique is an out-of-the-box idea in rehabilitation which doesn’t increase the loads on the historical structure since it depends on light and small size devices. As well، this new rehabilitation technique is interesting in attracting new class of visitors for historical structures and sites، i.e. children who are helped via this technique in exploring their history in an attractive way. The paper is written in Arabic since there is a lack in the Arabic literature about these rehabilitation techniques.
إن التكنولجيا سهلت الحياة كثيراً وجعلت ما كان مستحيلاً في الماضي متاحاً للجميع الآن ، ولكن هل يمكن أن تفيدنا التكنولجيا يوماً في مجال تأهيل المباني والمواقع الأثرية؟ لقد حاول العلماء كثيراً أن يسافروا بخيالهم لاختراع ما يسمي بآلة الزمن. فميل الانسان لان يعيش زمن غير زمنه متأصل في فطرته فهل يمكن الرجوع للماضي عن طريق المستقبل لإرضاء فطرة الانسان وفضوله؟ إن فكرة البحث بنظرة أوسع تعتمد علي وجود آلة الزمن في كل مبني أو موقع أثري، واله الزمن بالنسبة لهذا الموضوع هي العروض التخيلية ثلاثية الابعاد والتي أضحت من ضمن التقنيات الحديثة التي يتم الإعتماد عليها في تأهيل وإعادة إستخدام المباني والمواقع الأثرية. ولهذا مردود إقتصادي جيد للسلطات المالكة لهذه الآثار حيث أن الدراسات الإقتصادية واستطلاعات الرأي توضح أن أعداد الداخلين يومياً الي دور السينمات تساوي اضعاف أعداد الداخلين لأشهر المباني الاثرية في العالم. ويسلط البحث الضوء على ثلاث من التقنيات المختلفة التي يتم إستخدامها في هذه العروض وهي: السينما ثلاثية الأبعاد؛ والعرض ثلاثي الأبعاد بطريقة خرائط الإسقاط؛ والهولوجرام. وتظهر أهمية هذه التقنية في الخروج من الدائرة المغلقة لفكرة التأهيل وإعادة التوظيف للمباني الاثرية التقليدية عن طريق تقليل الأحمال الواقعة علي المبنى والناتجة عن إعادة التوظيف التقليدية نظراً حيث أن الوظيفة الجديدة باستخدام هذه التقنية تعتمد علي استخدام أجهزة خفيفة الوزن مستغلة الفراغ والعالم الافتراضي. وكذلك تجذب هذه التقنية فئات جديدة للإستمتاع بالمباني والمواقع الأثرية وهم الأطفال لأن هذه التقنية تساعدهم في معرفة تاريخهم بطريقة شيقة ومبسطة.

The discovery of the tomb of Meryneith is one of the recent and important discoveries in
Saqqara. The tomb was discovered in the period from 2001 to 2003 by the archaeological
mission of Leiden University (the Netherlands). The importance of the discovery goes back to
the positions held by the tomb owner Meryneith. He was the High Priest of Aton in the reign
of King Akhenaten and also was the Minister of Finance in the reign of King Tutankhamun.
The tomb was subjected to a complete restoration project. It was afterwards open for visit in
2011. The authors of this paper visited the tomb many times during late 2014 and October
2015. They conducted many times a detailed visual inspection of the tomb during those visits.
This paper discusses the tomb description and the signs of damage currently noticed and the
possible reasons behind. As well, it comments on the restorations carried out by the Holland
mission and comparing it with the tomb status at the time of the discovery. The paper aims at
comparing the restorations done with the basics and the common scientific rules in
architectural and fine restoration of monumental structures. The objective is to contribute in
improving the current situation of the tomb and to give recommendations for possible future
restorations of similar tombs.

This work intends to provide seismic vulnerability analysis for a building stock in Al Khalifa District, Fatimid Cairo while focusing on the historic buildings in the area. The work represents part of an interdisciplinary study targeting the management and conservation of a UNESCO World Heritage Site. The project inspects several aspects including behavior of masonry walls, structural health monitoring of selected structures, conservation studies, in addition to influence of rising ground water. In the current study, seismicity of Egypt generally and Cairo specifically is reviewed. Afterwards, large-scale seismic vulnerability is adopted to calculate the vulnerability index for buildings within the study area. Data are collected through extensive on-site surveys for more than one hundred buildings. Observed typologies are listed alongside possible mechanisms of failure. Egypt has moderate seismic hazard; however, many buildings are prone to damage due to inadequate seismic design. This leads to retrofitting requirements to reduce seismic vulnerability and adhere to imposed seismic requirements in design codes. The study is intended to understand seismic risk of buildings within study area as part of a comprehensive study. Developed vulnerability map show that many buildings are prone to damage during seismic events.

The paper presents an integrated approach aimed at assessing the seismic safety of Mallorca cathedral. This cathedral is an extraordinary historical construction dating back to the middle ages. The experimental modal parameters of the cathedral were identified using Ambient Vibration Testing (AVT). The cathedral numerical model was updated using the identified modal parameters. This updated model was then used to study the seismic response of the cathedral using non-linear static (pushover) analysis. A sensitively analysis was carried out to reveal the dependency of the seismic capacity on the input materials properties. To assess the seismic performance and the safety of the cathedral, the N2 method was employed. It was found that the cathedral is safe when subjected to the earthquakes expected in Mallorca Island.

Barcelona Cathedral is one of the most important monuments not only in Spain but also all over the world. The construction of the Gothic cathedral started in 1298 under King Jaume II and in 1460 the main building was completed. The two architects Josep Oriol Mestres and August Font i Carreras completed the construction of the gothic façade in 1889 and the central spire in 1913, following the same design previously proposed by the French architect Charles Galters in 1408. The central spire reaches a height of 90 m over ground level which makes it very vulnerable when subjected to lateral loads like wind and earthquakes. Being finished at the beginning of the 20th century (when the concept of reinforced concrete was being widely spread) gave the builders the chance to centrally reinforce all masonry beams of the spire with steel ties and nowadays these steel ties are facing very severe problems due to corrosion. A complete project for restoration of the spire is being executed nowadays in which a complete dismantling and reconstruction will be carried out. The steel ties will be replaced with titanium ones in order to eliminate the corrosion problem. In order to understand wind and seismic performance of the spire and the role and strength contributions of the steel ties, the different applied loads on the spire which are self weight, wind loads and earthquake loads have been estimated ,then a numerical model of the spire has been created and analyzed using the finite element program DIANA. First a linear elastic analysis under the effect of spire self weight then a combination of spire self weight and wind loads and finally a combination of spire self weight and earthquake loads. The high tensile stresses in masonry beams under the effect of the combination of spire self weight and wind loads and the combination of spire self weight and earthquake loads meant that linear elastic analysis wasn't enough to describe the structure behavior and a nonlinear analysis was essential. A nonlinear analysis under the effect of spire self weight (using three different constitutive models to describe masonry nonlinear behavior) was investigated and it revealed an elevated safety margin as the spire can carry more than ten times its self weight. Then to investigate the seismic performance of the spire a nonlinear static pushover analysis (using two different constitutive models) has been carried out.As a conclusion of this study the steel ties are highly needed to carry the tensile stresses resulted from seismic actions and the spire would be able to resist a maximum base shear of 420 KN (16% of the spire self weight).

Historical structures are vital to the realization of how the technical, artistic, and scientific skills of the human kind have developed over time. These structures are one of the motors of the tourism industry, and therefore, the studies related to their conservation do not only have social benefits but as well economical ones. It is unfortunately that many countries rich with valuable architectural heritage are characterized by high seismic activity, Italy and Turkey are obvious examples. Due to earthquakes, many invaluable historical structures have been lost forever. Consequently, there is an increasing need for more research on the topic of seismic assessment and protection of this class of buildings. This work contributes to the methodological approaches adopted for the seismic assessment of historical structures. In many cases, due to the lack of knowledge about the assessed historical structure, it is essential to combine many investigation activities in such approaches. The aim is to minimize any possibly required seismic strengthening interventions (minimum intervention concept) by increasing the level of knowledge about the structure. In the current research, the employed experimental investigation activities are the dynamic identification tests and the dynamic monitoring. Most approaches for dynamic monitoring are based on the use of a threshold limit which is used to trigger the system when the parameters measured surpass the limit. Here, an alternative is considered that consists of a continuous monitoring system based on the permanent measurement of the ambient vibration. A thermography monitoring is used as a complementary system for the measurement of temperature. The integration between the dynamic investigation and the numerical modeling is essential and it includes two main features. On one hand, tentative structural analyses are carried out to identify important aspects of the dynamic tests and monitoring strategies such as critical points of the structure where to place the sensors. On the other hand, the results of the dynamic investigation are used to perform model updating until obtaining a satisfactory structural model adequately matching the measured dynamic properties of the structure. Once the structural model is validated, it is used to carry out the seismic assessment of the structure. This assessment is performed using different methods, to cross check the results, including the pushover analysis, the kinematic limit analysis and the nonlinear dynamic analysis. It is then possible with these assessments to identify the seismic behavior of the structure. Using the N2 method, the evaluation of the structural performance and its safety are carried out. Hence, the needs for any possible seismic strengthening are revealed, keeping in mind, the respect to the "minimum intervention" concept. As an application, the cathedral of Mallorca (Spain) is taken as a case study. This structure is one of the largest cathedrals built during the Middle Age. For each of the previously mentioned research steps, the followed criteria and the experience gained are transferred into recommended methodological approaches to be applied to other historical structures. Finally, the integration of these partial steps into one integrated methodology is discussed.

The presented research aimed at studying the dynamic behavior of Mallorca cathedral (Mallorca Island, Spain) under ambient sources of vibration and seismic events. The cathedral is one of the greatest built masonry structures worldwide. It is characterized for its audacious dimensions and slender structural members. Because of it, the study of its dynamic behavior is a clear concern. The cathedral dynamic properties were firstly identified using ambient vibration testing. Afterwards, a dynamic monitoring system was implemented to continuously measure, record, and wirelessly transfer the acceleration records without having to set up an activating threshold. This monitoring type was implemented because of the low seismic intensity of Mallorca Island with a basic ground acceleration of only 0.04 g according to the Spanish seismic standard. The continuous monitoring allowed for capturing some seismic events and some drops in the natural frequencies were noticed because of a breathing crack effect. Using both ambient vibration testing and continuous monitoring system, global modes could be more accurately identified than more local ones. The identification of the global modes was more attainable than in the case of more local ones. The temperature was a more influential environmental parameter than humidity and wind for all of the identified modes except for one more directly depended on wind.

Cultural heritage buildings are prone to failures when subjected to seismic events, and recent earthquakes worldwide resulted in many losses of these buildings. Therefore, there is a need for methodologies for assessing their seismic safety that should be based on enough knowledge of the building. Here, dynamic investigation by dynamic identification testing and dynamic monitoring increase significantly the level of knowledge about the assessed building. The dynamic identification tests give global information about the dynamic properties like natural frequencies that are useful in calibrating and updating a numerical model of the building that could be used in the seismic safety evaluation. Dynamic monitoring gives the dynamic properties’ evolution in time and may be used as an early warning tool able to send alarms when meaningful changes in dynamic properties are observed. This chapter gives some considerations on the different investigation activities of dynamic identification, dynamic monitoring, numerical model updating, and seismic safety assessment of cultural heritage buildings. As an application, the case study of the historic Mallorca cathedral is discussed.

The spire of Barcelona cathedral suffered from severe problems due to the corrosion of the steel ties used in reinforcing its stone masonry beams. Wide visible cracks were noticed in the stone beams and large parts were detached. Therefore, the full spire was dismantled and reconstructed using titanium ties to eliminate the corrosion problem. A finite element model of the spire was created and analyzed using DIANA software to support this decision. This analysis helped in understanding the role and strength contributions of these ties in resisting the applied loads on the spire, specifically, the lateral loads of earthquakes and wind. A nonlinear static (pushover) analysis was carried out to assess the spire capacity under the lateral loads. A number of constitutive models for modeling the masonry behavior were tried. Also, a number of seismic actions patterns were considered. As a main conclusion of this study, the ties were highly needed to carry the tensile stresses caused by earthquakes and wind loads. Therefore, in the reconstruction of the spire, such ties must be kept in the masonry beams.

The paper presents the application of continuous dynamic monitoring and thermographic monitoring to the study of Mallorca Cathedral, one of the largest medieval structures built in Europe. The dynamic monitoring has been carried out by means of a network of three strong motion tri-axial accelerometers installed in December 2010. This network has allowed the capture of seven seismic events characterized by different epicenter locations and frequency contents. The post-processing of the information recorded during these events has provided significant insight on the cathedral dynamic response. The paper also presents the post processing of raw data of nine months of continuous dynamic monitoring, allowing the characterization of the effect of temperature changes on the natural frequencies of different mode shapes. A complementary study undertaken by thermographic monitoring, in which a part of the cathedral has been monitored for at least two weeks in summer and also in winter using an IR camera, is also presented. The relation between the stone masonry temperature of different structural elements (columns, vaults, arches, walls) and natural frequencies has been investigated. This study is part of a more detailed research, still in progress, aimed at investigating the seismic behavior and vulnerability of Mallorca Cathedral.