A review of methods applicable to the study of masonry historical construction, encompassing both classical and advanced ones, is presented. Firstly, the paper offers a discussion on the main challenges posed by historical structures and the desirable conditions that approaches oriented to the modeling and analysis of this type of structures should accomplish. Secondly, the main available methods which are actually used for study masonry historical structures are referred to and discussed. The main available strategies, including limit analysis, simplified methods, FEM macro- or micro-modeling and discrete element methods (DEM) are considered with regard to their realism, computer efficiency, data availability and real applicability to large structures. A set of final considerations are offered on the real possibility of carrying out realistic analysis of complex historic masonry structures. In spite of the modern developments, the study of historical buildings is still facing significant difficulties linked to computational effort, possibility of input data acquisition and limited realism of methods.

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Structural Analysis of Masonry Historical Constructions. Classical and Advanced Approaches

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Metal Foams A Design Guide

Damage and performance evaluation of masonry churches in the 2009 L’Aquila earthquake

SUMMARY Recent seismic events have caused damage or collapse of invaluable historical buildings, further proving 7 the vulnerability of unreinforced masonry (URM) structures to earthquakes. This study aims to understand failure of masonry arches—typical components of URM historic structures—subjected to horizontal ground 9 acceleration impulses. An analytical model is developed to describe the dynamic behaviour of the arch and is used to predict the combinations of impulse magnitudes and durations which lead to its collapse. The 11 model considers impact of the rigid blocks through several cycles of motion, illustrating that failure can occur at lower ground accelerations than previously believed. The resulting failure domains are of potential 13 use for design and assessment purposes. Predictions of the analytical model are compared with results of numerical modelling by the distinct element method, and the good agreement between results validates 15 the analytical model and at the same time confirms the potential of the distinct element framework as a method of evaluating complex URM structures under dynamic loading. Copyright q 2007 John Wiley & 17 Sons, Ltd.

Failure of masonry arches under impulse base motion

Since the late 1970s, nonlinear static analysis have had an increasing use in the seismic assessment of existing unreinforced masonry (URM) buildings. Different modelling strategies can be used to evaluate the global seismic response of these buildings, such as the Continuous Constitutive Laws Model (CCLM) and the Equivalent Frame Model (EFM). Despite the CCLM modelling approach seems to be the most suitable at this aim, it needs many input data, which are often quite difficult to be known, and requires a high computational effort. For this reason, the EFM, which is based on strongly simplified hypotheses, is preferred in professional practice, where a small computational burden and a time- and cost-saving structural analysis by using few mechanical parameters is needed. In this paper, a review of its uses and limits is proposed, in order to identify the most critical issues and define its proper use in professional practice when applied to existing URM buildings. As a result, it is highlighted that the EFM can be reasonably used as a first conservative approach for the seismic assessment of existing URM buildings with box behaviour and quite regular opening patterns. Thus, up to now, from this review its use is encouraged in seismic analysis of existing URM buildings after providing them a reduction of their floors and roofs deformability, an adequate wall-to-floor and wall-to-roof connections and a regularization of the opening patterns.

Uses and limits of the Equivalent Frame Model on existing unreinforced masonry buildings for assessing their seismic risk: A review

Sandwich foam beams, made of solid skins and aluminium foam core, are usually applied in high-tech engineering field while they are not yet adopted in civil structures. An initial, explorative study on the structural application of metal foam is presented in this paper. The potentials of sandwich foam beams are studied through analytical models and parametric analyses; the sensitivity of the flexural response of the media to the total amount of pores and their spatial distribution are investigated. An analytical tool able to design functionally graded beams of metallic foam is presented and applied with reference some commercial aluminium foams. An experimental campaign is being planned to validate the presented results.

Design of Functionally Graded Beam of Aluminium Foam for Civil Structural Application

The severe damage to masonry buildings after earthquakes has pointed out the need of studying new seismic protection techniques in order to guarantee appropriate safety levels against earthquakes. In historical buildings, such as basilica churches, a seismic rehabilitation should have also a minimum impact on the construction, preserving the original structure as far as possible. The Base Isolation System (BIS) balances the opposite requirements of structural safety and architectural preservation. In this article, the design of BIS for retrofitting masonry churches is discussed and applied to four case studies. Dynamic behavior of the isolated structures is evaluated and compared with the “as is” structures. Some major design issues are examined, namely: the use of mixed isolation system for lightweight buildings; the values of design vertical stress on isolators and the effect of selecting different rubber compounds and isolator geometry; and the effect of rigid slab at the isolation plan on the stress d...

Design Aspects in Seismic Isolation: Application to Retrofit Churches

Prove sperimentali di isolatori elastomerici: influenza del carico verticale V e del fattore di forma secondario S2.

Implications of code provisions in the seismic design of concentric braced frames

Publisher Summary
This chapter focuses on an experimental program on welded beam-to-column connections aimed at evaluating the effect of the column dimensions and panel zone design on the cyclic behavior, ultimate strength, and deformation capacity of the welded connections, varying the applied loading history. A total of 18 beam-to-column fully welded joints are designed, fabricated, and tested up to failure under different loading histories. The specimens, made of S235 JR steel, are T-shaped beam-column subassemblages, consisting of a 1000 mm long beam and 1800 mm long column. In the three types of specimens—respectively appointed as BCC5, BCC6, and BCC8–the beam cross-section is the same, while the column cross-section is varied, being respectively HE160B for the BCC5 series, HE200B for the BCC6 series, and HE240B for the BCC8 series. The basic monotonic stress-strain curve and the mechanical properties of the specimen steel components are determined through coupon-tension tests. The values of the total rotation capacity, in the increasing amplitude test, reach 0.064 rad for the BCC5 specimen, 0.053 rad for the BCC6 specimen, and 0.046 rad for the BCC8 specimen. These values correspond to low values of beam plastic rotations, respectively, equal to 0.0057, 0.0175, and 0.0242 rad for the three specimens, thus confirming that large rotations can be experienced due to the column web panel deformations.

Elena Mele

Papers

Design of Functionally Graded Beam of Aluminium Foam for Civil Structural Application

Design Aspects in Seismic Isolation: Application to Retrofit Churches

Prove sperimentali di isolatori elastomerici: influenza del carico verticale V e del fattore di forma secondario S2.

Implications of code provisions in the seismic design of concentric braced frames

Cyclic Behaviour of Beam-to-Column Welded Connections