Search

Increasing energy efficiency of final energy consumption is a very actual and important topic, in parallel with activities and measures worldwide targeting an increased share of renewable energy sources. Despite recent expansion in building construction, old buildings characterized by high energy consumption still represent a great majority of both residential and public building stock in many countries in the Balkan region. Located in seismic-prone countries, such as the Republic of North Macedonia, these old buildings are also characterized by the high risk of partial or complete destruction during earthquakes. This imposes the need for mandatory screening at the outset of an energy efficiency program, which will categorize buildings according to seismic risk and thus determine which buildings are suitable for energy efficiency investments. This paper presents how the methodology for high-level seismic screening, originally proposed in the World Bank's Country Report (North Macedonia), is extended and customized by the Institute of Earthquake Engineering and Engineering Seismology, IZIIS, Skopje to correspond to the country specificities, i.e., to be based on overall knowledge on aseismic design and construction practice in the country, detailed on-site inspection of each particular building, and to be carried out by structural engineers with appropriate knowledge and experience in earthquake engineering. The high-level seismic screening was performed in the Republic of North Macedonia, applying this extended and customized methodology, for a total number of 27 medical facilities, dominantly healthcare centers, and 50 municipality buildings (schools, kindergartens, and municipal buildings).

The historic building of “Sokolski dom” in Kumanovo belongs to the plain masonry type of buildings. Built in the thirties of the last century for the needs of the “Sokolski Society”, this building was once the main impetus for enrichment of cultural, entertainment and sports life, enabling the proper development of many generations. Due to its significance it was put under the protection as cultural-historic heritage in the country. The subject of this paper is a detailed analysis of the stability of existing structure, which proved the need for its repair and seismic upgrading. With detailed analysis of the bearing and deformation capacity it was determined that the existing structure does not meet the requirements according to the national regulations. Therefore, the need for repair and strengthening was imposed, with the main goal of ensuring seismic stability of the building. Considering the possibilities and certain limitation for structural interventions from one hand, and the required bearing and deformation characteristics of the elements and the structure as whole from other hand, a traditional solution for strengthening was adopted, by reinforced concrete jackets and horizontal belt course. This technical solution provides increase of the structural bearing and deformation capacity of the system, as well as its ductility capacity, which is especially important for this type of buildings in case of seismic excitations. By increasing the deformation capacity, the input energy in the system would be consumed, which would greatly increase the seismic safety and security of the building.

The structure of the Clock Tower in Skopje is massive, constructed of stone masonry with a height of about 29 meters and brick masonry in the upper octagonal part. It was damaged during the Skopje Earthquake in 1963. A rehabilitation of the structure was carried out in 1964, but without a seismic strengthening. Recently, field investigations were carried out and a three-dimensional analysis of the structure in its actual state for gravitational and seismic forces was performed. It has been concluded that it is necessary to perform protective interventions to ensure longer-term protection, stability and further existence in the form of repair of existing structural damage, structural consolidation, repair of damaged timber elements and strengthening. To improve the behaviour and resistance to dynamic impacts, a technical solution for consolidation and retrofitting has been proposed. The basic concept consists of existing structural damage rehabilitation, structural consolidation with systemic injection, rehabilitation of load-bearing wooden beams and braces and strengthening the whole structure. Due to the specificity of the structure of the Clock Tower in terms of its shape, used material, structural system and the type of structural elements, as well as its importance as a cultural and historical heritage, which requires respect of certain conservation principles and rules, the options for rehabilitation and strengthening are strictly limited. It excludes inserting new structural elements that would provide sufficient ductility during maximum expected earthquakes. The rehabilitation and strengthening were carried out with innovative composite materials that were experimentally verified, but never applied before. The analysis results show that the retrofitted structure can withstand the maximum expected seismic loads according to the actual technical regulations.

The impact of present building code requirements for seismic design of new buildings can readily be acknowledged, however applying regulation to existing buildings is an area less well defined. Presently, there is a diverse list of existing code references which could be interpreted to require seismic upgrades of existing structures. Unfortunately, these references do not provide a clear path toward addressing the hazards, evaluation and retrofitting of existing buildings. And when it comes to existing old buildings and monuments, constructed with low or no seismic consideration, the topic becomes much more complex and challenging. The problem of earthquake protection of historic buildings and monuments is radically different from that of other existing structures, due to the priority given to preservation of aesthetic, architectonic and historic values instead of keeping the structure operational. In providing the protection of these structures in a manner that requires the least intervention and the greatest care to preserve authenticity, the experts are permanently challenged by the fast development and the improved performance of new materials and techniques. This paper presents the integrated multidisciplinary approach to seismic protection of important structures that has been developed by the Institute of Earthquake Engineering and Engineering Seismology, IZIIS, Skopje, and implemented in the process of seismic upgrading or reconstruction of historic buildings and monuments in the country and beyond.

Republic of North Macedonia is a seismic prone country with a long tradition and positive experience in the field of seismic design of new and strengthening of the existing buildings up to pre-defi...

As part of the development of a European Seismic Risk Model 2020 (ESRM20), the spatial and temporal evolution of seismic design across Europe has been studied in order to better classify reinforced concrete buildings (which represent more than 30% of the approximately 145million residential, commercial and industrial buildings in Europe) and map them to vulnerability models based on simulated seismic design. This paper summarises the model that has been developed to assign the years when different seismic design levels (low code, moderate code and high code) were introduced in a number of European countries and the associated lateral forces that were specified spatially within each country for the low and moderate codes for typical reinforced concrete mid-rise buildings. This process has led to an improved understanding of how design regulations evolved across Europe and how this has impacted the vulnerability of the European residential building stock. The model estimates that ~ 60% of the reinforced concrete buildings in Europe have been seismically designed, and of those buildings ~ 60% have been designed to low code, ~ 25% to moderate code and 15% to high code. This seismic design model aims at being a dynamic source of information that will be continuously updated with additional feedback from local experts and datasets. To this end, all of the data has been made openly available as shapefiles on a GitLab repository.

In this paper, a two-level multi-group approach to seismic performance assessment of existing building stock is presented and discussed. The first level of assessment is a simple visual screening based on the principles originally developed in FEMA (Rapid visual screening of buildings for potential seismic hazards: a handbook—FEMA 154 and 155, Applied Technology Council, Redwood City, 2002). The second level of assessment is based on an integrated approach (field survey, geotechnical investigations, experimental testing and analytical investigations) with incorporated procedures of different levels of complexity. The acceptance criteria for assessment are founded on demand versus capacity relationships, defined at element and story level. The developed approach was applied in performance assessment of the existing buildings in Karposh, which is one of the largest and oldest municipalities in Skopje, the capital of the Republic of Macedonia. Rapid visual screening (level_1 activity) was performed for 161 existing buildings. For two selected buildings, level_2 assessment was carried out. The results from the assessment were uploaded into the existing geo-referenced building inventory database on the Karposh municipality that represents a practical tool for the decision makers in enforcing decisions on design and construction of seismically resilient building environment.

This public report provides an overview of the problems raised by the management of heritage buildings and sites (HBs/sites) in their surroundings. A multidisciplinary team comprising conservation professionals, art historians, archaeologists, architects, biologists, civil engineers and information technology experts have joined forces within the framework of the European Cooperation in Science and Technology1 Action TD1406 - i2MHB (Innovation in Intelligent Management of Heritage Buildings) to provide their expertise and experience on the risks to which HBs/ sites are exposed (urban development, infrastructure works, demographical changes, natural and technological hazards, bio-deterioration, lack of cultural heritage education and technical knowledge and skills, etc.). Traditional and new approaches to manage the principal risks are then developed. Nine representative European HBs/sites are used to illustrate the different problems raised and to offer possible solutions. The report ends with a number of recommendations to better integrate HBs/sites in their surroundings. This report is addressed to policy makers at the local, regional and national governments; economical and industrial players; research and education stakeholders; and, the public to the preservation and valorisation of HBs/sites in their surroundings. We hope that readers will find tentative answers to their question(s) on the difficulties encountered by the management of HBs/sites in their surroundings. Further reading is available through the references and the online literature provided.

The problem of earthquake protection of historic structures and monuments is radically different from that of other structures, due to the priority given to the preservation of the aesthetic, architectonic and historic value, instead of keeping the structure operational. In their effort to protect these structures with the least intervention and the greatest care to preserve authenticity, experts are challenged by the fast development and improved performance of new materials and techniques. However, the implementation of a particular strengthening methodology depends on the extent it has been investigated. Proving the effectiveness of a selected consolidation system can be successfully overcome by design assisted by testing. This Chapter presents the implementation of an original, experimentally verified strengthening methodology in the reconstruction of three very important cultural-historic monuments.

The cultural-historic heritage is the key element for the history and the identity of society, contributing to its economic and general well-being. Damages caused to historic buildings and monuments by earthquakes that occurred in the past are irreversible and these lost “documents” cannot be retrieved. In providing the protection of these structures in a manner that requires the least intervention and the greatest care to preserve authenticity, the experts are permanently challenged by the fast development and the improved performance of new materials and techniques. However, the implementation of particular strengthening methodology depends on the extent it has been investigated as well as its analytical and experimental verification. This paper presents the most important seismic shaking table investigations of models of historic buildings and monuments carried out in the IZIIS’ Dynamic Testing Laboratory, the main goal of which was assessment of the vulnerability of structures as well as testing and experimental verification of different methodologies for seismic strengthening.