Dr. Eng. Ahmed Elyamani

This research aims at throwing the light on one of the few survived examples of Ancient Egyptian vaulted structures; those are the storerooms of the temples of the Ramesseum and Sety I built in the 13th century BC. In the first case, only some of the adobe vaults and walls are still standing; whereas in the second case all the vaults collapsed and only the walls exist. Due to lack of maintenance and also scientific research on this topic, the survival remains may be lost forever. The research started with tracking the chronological development, the architecture and the construction of the adobe barrel vault in Ancient Egypt. The two case studies of the research were visually inspected and the existing damage symptoms and causes were reported and investigated. A structural analysis were carried out to understand the structural behavior and the causes of damage. Finally, a number of interventions were proposed that may help the existing ruins to survive.

The paper presents the current state of an on-going research aimed at characterizing the seismic response of Mallorca cathedral. Mallorca cathedral is an audacious Gothic structure built in the island of Mallorca during 14th-16th centuries, characterized for its large dimensions and slender structural members. So far, experimental and numerical modal analysis, in addition to tentative model updating and seismic analysis, have been performed. The dynamic identification tests have been carried out by ambient vibration testing, while the frequency domain decomposition (FDD) technique has been used to obtain the modal parameters. A 3D Finite Element (FE) model has been used to determine the vibration modes. The model has been updated by modifying some structural parameters to improve the matching between experimental and numerical modal parameters. Once updated, the model has been utilized to study the seismic response of the cathedral using non-linear static pushover analysis. Conclusions on the possible collapse mechanisms and the seismic performance of the structure are presented.

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.

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.

Historic Cairo has been a UNESCO World Heritage Site since 1979. It has more than 600 historic structures, which require extensive studies to sustain their cultural, religious, and economic values. The main aim of this paper is to undertake dynamic investigation tests for the dome of Fatima Khatun, a historic mausoleum in Historic Cairo dating back to the 13th century and consisting of mainly bricks and stones. The challenge was that the structure was difficult to access, and only a small portion of the top was accessible for the attachment of accelerometers. Current dynamic identification procedures typically adopt methods in which the sensors are arranged at optimal locations and permit direct assessment of the natural frequencies, mode shapes, and damping ratios of a structure. Approaches that allow for the evaluation of dynamic response for structures with limited accessibility are lacking. To this end, in addition to in situ dynamic investigation tests, a numerical model was created based on available architectural, structural, and material documentation to obtain detailed insight into the dominant modes of vibration. The free vibration analysis of the numerical model identified the dynamic properties of the structure using reasonable assumptions on boundary conditions. System identification, which was carried out using in situ dynamic investigation tests and input from modelling, captured three experimental natural frequencies of the structure with their mode shapes and damping ratios. The approach proposed in this study informs and directs structural restoration for the mausoleum and can be used for other heritage structures located in congested historic sites.

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.

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.

This paper presents an experimental investigation into the structural and material response of ambient-dry and wet clay-brick/lime-mortar masonry elements. In addition to cyclic tests on four large-scale masonry walls subjected to lateral in-plane displacement and co-existing compressive gravity load, the study also includes complementary tests on square masonry panels under diagonal compression and cylindrical masonry cores in compression. After describing the specimen details, wetting method and testing arrangements, the main results and observations are provided and discussed. The results obtained from full-field digital image correlation measurements enable a detailed assessment of the material shear-compression strength envelope, and permit a direct comparison with the strength characteristics of structural walls. The full load-deformation behaviour of the large-scale walls is also evaluated, including their ductility and failure modes, and compared with the predictions of available assessment models. It is shown that moisture has a notable effect on the main material properties, including the shear and compression strengths, brick–mortar interaction parameters, and the elastic and shear moduli. The extent of the moisture effects is a function of the governing behaviour and material characteristics as well as the interaction between shear and precompression stresses, and can lead to a loss of more than a third of the stiffness and strength. For the large scale wall specimens subjected to lateral loading and co-existing compression, the wet-to-dry reduction was found to be up to 20% and 11% in terms of stiffness and lateral strength, respectively, whilst the ductility ratio diminished by up to 12%. Overall, provided that the key moisture-dependent material properties are appropriately evaluated, it is shown that analytical assessment methods can be reliably adapted for predicting the response, in terms of the lateral stiffness, strength and overall load-deformation, for both dry and wet masonry walls.

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.

This research paper deals with Sednaoui El-Khazender building which is one of the unique buildings in Cairo dating back to the beginning of the 20th c. It was designed by the famous French Architect Eiffel. The building was visually inspected and the different signs and symptoms of damage were identified. Intervention techniques were proposed for the restoration of the building. A proposal for the rehabilitation of the building is discussed aiming at maximizing the economic benefits of the building.
يتناول هذا البحث أحد المباني ذات الطراز المعماري الفريد وهو مبنى صيدناوي الخازندار بمنطقة العتبة، والذي يرجع تاريخ تشييده إلي أوائل القرن العشرين، وصممه المعماري الفرنسي الشهير إيفل (مصمم برج إيفل بباريس). تمت معاينة المبنى وتشخيص أهم مظاهر وعوامل التلف المؤثرة عليه، ثم تم وضع اقتراحات الترميم والعلاج. لتعظيم الإستفادة الإقتصادية من المبنى فقد تم وضع مقترحات لتأهيله وإعادة إستخدامه بما يتوافق مع محيطه العمراني وقيمته المعمارية الكبيرة.