Dr. Eng. Ahmed Elyamani

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 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.

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 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.

This paper summarizes recent investigations into the structural and material response of ambient-dry and wet clay-brick and lime-mortar masonry elements, with focus on those used in heritage structures in Historic Cairo. In addition to cyclic tests on large-scale masonry walls subjected to lateral displacement and compressive gravity loads, the studies included complementary tests on small scale masonry panels and material specimens. It is shown that moisture can have 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 in addition to a reduction in ductility. Simple and cost-effective strengthening techniques, using textile-reinforced mortars, for enhancing the lateral performance of low-strength heritage masonry element, are also considered in this study. The effectiveness of the strengthening approach is illustrated and quantified through additional tests on the small-scale panels and large-scale wall specimens. It is shown that simple analytical assessment methods can be reliably adapted for predicting the response of the wall specimens, in terms of the lateral stiffness, strength and overall load-deformation behaviour.

This paper examines the experimental structural response of clay brick lime mortar masonry walls in wet and ambient-dry conditions. The properties of fired-clay bricks and hydraulic lime-mortar materials are selected to resemble those of existing heritage masonry structures in Historic Cairo. The investigation includes tests on square panels under diagonal compression, and large-scale walls subjected to gravity loading and in-plane lateral cyclic displacements. In addition to the conditioning type, the effectiveness of strengthening with helical bars in horizontal bed joints is also investigated. Implications of embedding helical bars in lime mortar as well as the provision of end anchorages are assessed. The complete load-deformation response of the large-scale members is also evaluated, including the main behavioural characteristics and failure modes. The results show that moisture has a notable effect on the main mechanical properties and overall structural response of such masonry components. For the panels subjected to diagonal compression, the strength reduction under wet conditions is shown to be more than 40% compared to the dry counterparts. For the large-scale walls, subjected to combined lateral loading and precompression, this reduction is significantly lower but can exceed 10%. It is also shown that the provision of helical bars can, depending on their end anchorage and arrangement, double the diagonal tension strength of masonry and offset the adverse effects occurring due to moisture.

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 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 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.

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.