Performance of a Post-Byzantine Triple-Domed Basilica under Near and Far Fault Seismic Loads

In this Chapter a triple-domed basilica constructed at the end of the 19th century is selected as a case study to present a methodology for the selection of the appropriate intervention techniques in monumental structures. The methodology includes in-situ and laboratory testing, application of analytical methods, consideration of geotechnical parameters and regional seismicity. Seismic loads are estimated according to contemporary and older concepts for seismic design. Since the impact of near-fault phenomena on masonry structures has not been thoroughly studied, although considered as responsible for extensive structural damage during major seismic events, a procedure is presented in order to account for the special characteristics of strong ground motion, in the so-called near-fault region. The seismic performance of the structure before and after interventions, using traditional and new technology, is assessed by applying a validated finite element model. Also, the out-of-plane behavior of structural parts is evaluated through kinematic analysis of selective collapse mechanisms.

Seismic Vulnerability Assessment of Masonry Building from Ottoman Period in Bosnia and Herzegovina

Traditional art of building in Bosnia and Herzegovina comprises brick or stone masonry structures. Most historical buildings belonging to national cultural heritage were made of stone-masonry. The country is situated in seismic active region of South-East Europe. In the case of strong earthquake motion such buildings could suffer heavy damages. Some structural elements of historical buildings, as domes and arches, cracked already by moderate earthquake but without the loss of stability. Substantial damages were caused by recent war disaster. Damages could be accumulated through the history as well. Generally, stone-masonry buildings in Bosnia and Herzegovina can be classified in vulnerability classes between A and C according to European Macroseismic Scale. Design and construction procedures for rehabilitation are presented here with examples of repair and strengthening of mosques, which present historical stone masonry structures dating from the Ottoman period in Bosnia and Herzegovina. Traditional and contemporary materials were used for their rehabilitation. It is important to preserve original forms, especially those of damaged elements. The challenge for structural engineers and architects was to find equilibrium between aesthetical and structural demands.

Seismic Performance of a Mixed Masonry-Reinforced Concrete Building

The 6th of April 2009, a quite strong earthquake of magnitude ML =5.8 (Mw=6.3), struck in the city of L'Aquila. The seismic event caused serious injure to several masonry buildings, compromising a large part of the valuable historical and architectural heritage. The present work deals with seismic performance evaluation of an existing mixed masonry-reinforced concrete building in downtown L'Aquila city. A comprehensive discussion on the current limit capacity of the building based on the visual inspections of the occurred seismic damage, the experimental data from a wide campaign of on-site tests on the material properties, the results of numerical simulations from different naturally discrete models of the mixed masonry-reinforced concrete structure are presented. The seismic performance is evaluated through well-recognized N2 nonlinear static procedure. The Frame by Macro-Elements method is used to define an equivalent 3D frame representation of the structure. The obtained numerical results are directly compared with the surveyed damages.

In-Situ Static and Dynamic Testing and Numerical Modelling of the Dome of the Siena Cathedral (Italy)

The chapter reports on the in-situ experimental campaign and the numerical modelling that were performed to assess the static and dynamic behaviour of the Cupola of the Siena Cathedral in Italy: an irregular polygonal masonry structure built in the 13th century and composed of two domes. The research was motivated by the failure of some of the stone-trusses which connect the two masonry domes and consists of: a) single and double flat-jack tests in the internal dome, b) dynamic vibration tests on the Cupola under environmental (wind) and artificial (vibrodyne) loads and c) dynamic vibration tests on the double colonnade located below the Cupola (hammer impact tests). Results of tests were employed to identify a numerical model of the Cupola, which allowed to simulate its structural behaviour and to account for the failure of the stone-trusses between the two domes. The numerical model was later extended to the whole Cathedral. Through the discussion of an emblematic case study, the chapter shows a careful application of non-destructive testing (NDT) and numerical modelling in the field of assessment (and rehabilitation) of heritage buildings.

A Case Study for Seismic Assessment and Restoration of Historic Buildings

This chapter focuses on seismic assessment and restoration of one of the numerous historical buildings in Turkey; the Arditi Residence in Urla, Izmir. It is a 150 years old two story masonry building located in a seismically active region. From the structural point of view, the building can be regarded as a mixed system since three different techniques had been used during the construction. The Arditi Residence has been investigated in three stages: preliminary evaluation, seismic performance assessment and intervention. The building has been observed to possess serious deficiencies, which are not easy to handle due to the complexity of the construction system. On the other hand, the proposed intervention strategies should have the minimal impact on the historic information building carrying and provide a certain level of safety against the seismic demands. Overall, the chapter presents a contribution to seismic assessment and restoration of historical structures on the basis of Arditi Residence, a unique historical building with serious problems in an earthquake-prone region.

Traditional Timber Frame Walls

Timber frame construction is a characteristic of several historic city centres as well as of vernacular architecture in several countries around the world, either motivated by the availability of materials and construction traditions or by the need of reducing the seismic vulnerability of buildings, namely in south European countries, where this construction technique was adopted for seismic-resistance purposes. From past earthquakes, it has been seen that timber frame construction can be viewed as an interesting technology as it has exhibited a very reasonable behaviour when compared to other traditional construction techniques such as masonry walls. This chapter provides an overview of the main insights on the seismic performance of timber frame buildings from the evidences of past earthquakes and provides the main results of recent research focused on the in-plane cyclic behavior of timber frame walls with distinct geometrical configurations. Additionally, the main seismic performance indexes of timber frame walls, both unreinforced and retrofitted, are presented and discussed in detail.

Structural Identification and Numerical Models for Slender Historical Structures

In the present chapter the theoretical basis of different methods developed for the calibration of FEMs are discussed. In general, Model Updating techniques are based on the use of appropriate functions that iteratively update selected physical properties (characteristics of the materials, stiffness of a link, etc.). In this way the correlation between the simulated response and the target value could improve if compared to an initial value. The FE model thus obtained can be used for a detailed structural analysis with a great confidence. The technique described in the first part of the chapter is applied to the evaluation of the structural properties of the tower of the Provincial Administration Building in Bari (Italy).The final purpose is to predict the performance of the tower to different combinations of static and dynamic loads, i.e. earthquakes or other induced vibrations. Ambient vibration tests have been performed on the above mentioned tower with the aim of determining its dynamic response and developing a procedure for modeling this building (Foti et al., 2012a). The Operation Modal Analysis (OMA) has been carried out both in the frequency domain and in the time domain to extract the dominant frequencies and mode shapes of the tower.

Emerging Technologies and Materials for the Seismic Protection of Cultural Heritage

Cultural heritage artifacts and buildings are under a constant thread of destruction during devastating earthquakes. Any intervention should be such that it neither violates their form nor changes drastically their structural behavior and should be reversible. In addition, the materials to be used must be compatible with the ones the monument is constructed of. Traditional seismic retrofitting techniques have the disadvantage that most of them violate the above conditions. An alternative approach is the use of innovative seismic-protection systems to enhance the seismic resilience of cultural heritage against the effects of earthquakes, which is reported in this chapter. The potential of seismic-isolation strategy to mitigate the seismic risk of museum artifacts will be first exploited. Subsequently, the state of the art of the use of energy-dissipation devices, such as viscous dampers and shape memory alloys, as well as innovative materials such as FRPs, for the protection of monuments and historic structures will be presented.

Selected Assessment and Retrofitting Application Techniques for Historical Unreinforced Masonry Buildings

This chapter includes application of recent research on the repair and strengthening of historical structures and provides a structural assessment of five historical mosques in Albania. Apart from visual inspection, terrestrial laser scanner (TLS) data are used to analyze the historical structures. The FEM analysis conducted in SAP2000 aims to investigate the structural behavior of the undamaged model under static and dynamic loads. Stress concentration and mode period results have a considerable difference, which highlights earthquake vulnerability and changes the strategy of possible retrofitting. As a result, possible practical solutions for the structural problems based on previous research and enhancement of the existing structural resistance are suggested.

Non-Destructive Testing for Assessing Structural Damage and Interventions Effectiveness for Built Cultural Heritage Protection

Non-destructive techniques - NDT are used in the field of built cultural heritage protection, as they are applied in-situ and do not require destructive sampling. Infrared thermography is used for materials/decay mapping, assesses the compatibility and effectiveness of restoration materials and interventions, and reveals moisture transfer phenomena within structures. Ultrasonic testing assesses the residual properties of historic materials, reveals the decay layers and evaluates the effectiveness of consolidation treatments. Ground penetrating radar reveals the internal structure of masonries, identifies and locates subsurface voids, structural cracks and incontinuities. Portable imaging systems, in conjunction with digital image processing, are used for in-situ materials characterization, and for the study of the decay typologies. Data management systems correlate data from NDTs, from other methods and from seismic/environmental impact assessment analyses to evaluate the preservation state of a historic structure and to plan interventions.