Experimental evaluation of shear and compression strength of masonry wall before and after reinforcement: Deep repointing

Masonry presents some inadequacies due to its almost total lack of tensile strength. Typical damage to multiple leaf walls during earthquakes is the loss of bond between the leaves with consequent collapse of the external leaf. Retrofitting or repair of this damage is a very difficult task. In many cases grout injection or wall jacketing fail due to incompatibility with the construction technique of the walls. A complementary technique to the grouting has been proposed by the authors. Experimental results and applications of the technique on site have shown positive characteristics and the results of tests carried out on site show, in some cases, increases in shear strength and stiffness of the masonry walls

El comportamiento a largo plazo de torres y estructuras de fábrica. El Campanario de la Catedral de Monza

[EN] After the collapse of some heavy buildings and towers in Italy and elsewhere, the hypothesis of possible continuous damage to these structures due to the dead and cyclic loads (wind, temperature variations, etc.) has been formulated by the authors. The long term behaviour of historic masonry has also been detected by laboratory creep and cyclic tests. The results indicate that a laboratory and on site investigation together with analytical modelling are important peculiarly for tall bell-towers. The application of these procedures on the Bell-Tower of the Cathedral of Monza is here reported and discussed.[ES] Tras el colapso de varios edificios de fábrica y torres en algunos países como Italia, los autores han formulado la hipótesis de un posible deterioro continuo de dichas estructuras debido tanto a las solicitaciones derivadas del peso propio como de las cargas cíclicas (viento, variaciones de temperatura, etc). El comportamiento a largo plazo de la mampostería histórica ha sido también objeto de estudio mediante un seguimiento continuo de ensayos en laboratorio y la aplicación de pruebas cíclicas. Los resultados indican que una investigación, tanto en laboratorio e in situ, sumada a una modelización analítica puede resultar fundamental en casos de campanarios de cierta altura. A continuación, se propone la aplicación de dichos procedimientos en el Campanario de la Catedral de Monza.La investigación ha sido apoyada por el CNR-GNDT, MURST y la parroquia de Monza. Los autores desean agradecer a los Srs. P. Perolari, G. Ghilardi, M. Cucchi, M. Antico, C. Arcadi y M. Iscandri por su ayuda y colaboración en el trabajo experimental tanto in situ como en laboratorio.Binda, L.; Saisi, A.; Tiraboschi, C. (2018). El comportamiento a largo plazo de torres y estructuras de fábrica. El Campanario de la Catedral de Monza. Loggia, Arquitectura & Restauración. (22-23):108-121. doi:10.4995/loggia.2010.3040SWORD10812122-23Archivio Capitolare di Monza, Sezione Cronache 2, 1805-1838Archivio di Stato di Milano, Fondo Religione, Cartella 2566Biblioteca Capitolare di Monza, Burocco-Sirtori, Annuali di Monza, Vol.III, 1770-1850Biblioteca Capitolare di Monza, Burocco-Sirtori, Annuali di Monza, Vol.IV, 1770-1850Anzani A, Binda L, Mirabella Roberti G: A Numerical Interpretation of Long-term Behaviour of Masonry Materials under Persistent Loads. 4th STREMA, Architectural Studies, Materials & Analysis, Computational Mechanics Publications, Vol. 1, 1995; 179-186Astori B, Bezoari G, Guzzetti F: Analogue and Digital Methods in Architectural Photogrammetry. XVII Int. Congress of Photogrammetry and Remote Sensing, Commission V,Washington 1992Binda L, Gatti G,Mangano G et al.: The Collapse of the Civic Tower of Pavia: a Survey of the Materials and Structure. Masonry International 1992:11-20Binda L,Mirabella RobertiG, Poggi C: Il Campanile del Duomo di Monza: valutazione delle condizioni statiche. Editoriale L'Edilizia 1996; 7/8: 44-53Binda L, Poggi C: Ricerca volta a stabilire le condizioni statiche del Campanile del Duomo di Monza mediante analisi chimiche, fisiche e meccaniche dei materiali. D.I.S. Politecnico di Milano; 1996Binda L, Poggi C: Ricerca volta a determinare il comportamento meccanico della muratura del Campanile del Duomo di Monza mediante procedure sperimentali e simulazioni numeriche. D.I.S. Politecnico di Milano; 1997Binda L, Anzani A,Mirabella Roberti G: The failure of ancient Towers: problems for their safety assessment. Int. Conf. on Composite Construction - Conventional and Innovative, Zurich, 1997; 699-704Binda L., Tiraboschi C., Flat-jack Test as a Slightly Destructive Technique for the Diagnosis of Brick and Stone Masonry Structures, 8th Int. Conf. Structural Faults and Repair, CD-ROM, 1999L. Binda, A. Saisi, C. Tiraboschi, Investigation procedures for the diagnosis of historic masonries, Construction and Building Materials, ed. Elsevier-Norwich, Vol. 14, N. 4, June 2000, pp. 199-233L. Binda, A. Saisi, C. Tiraboschi, Application of sonic tests to the diagnosis of damaged and repaired structures, Non Destructive Testing and Evaluation International, ed. Elsevier Science Ltd., Vol. 34, N. 2, January 2001, pp. 123-138L.Binda,A. Saisi, S.Messina, S. Tringali,Mechanical damage due to long term behaviour of multiple leaf pillars in Sicilian Churches, III International Seminar on Structural Analysis of Historical Constructions, University of Minho, Guimarães (Portugal), 7th-9th November 2001, pp. 707-718L. Binda, C. Modena, A. Saisi, R. Tongini Folli, M.R. Valluzzi, Bed joints structural repointing of historic masonry structures, 9th Canadian Masonry Symposium Spanning the Centuries with Masonry, Fredericton (Canada), 4-6 June 2001, CD-ROML. Binda, A. Anzani, A. Saisi, G. Mirabella Roberti, Structural Integrity in Historic Structures, in AA.VV, Comprehensive Structural Integrity. Fracture of Materials from nano to macro, Volume I: Structural Integrity Assessment -Example and Case Studies, Editors I. Milne, R.O. Ritchie, B. Karihaloo, Pergamon Elsevier Science, Oxford, Vol. 1, Cap. 1.02, 2003, pp. 25-47Gantert Engineering Studio: Technical opinion about the collapse of the Bell Tower of St. Maria Magdalena in Goch (Germany). November 1993C. Gentile, A. Saisi, L. Binda, Dynamic investigation of a historic masonry Bell Tower, 6th International Masonry Conference, London, 4th-6th November 2002, pp. 192-199Gentile C., Saisi, A., Dynamic-based F.E. model updating to evaluate damage in masonry towers, IV International Seminar Structural Analysis of Historical Constructions (P. Laurenço, C. Modena, P. Roca Eds.), Padova 10th -12th November 2004, Balkema, Vol. 1, pp. 439-449Iacono B: Noto, la Cattedrale: cenni storici ed architettonici dalle origini al crollo. In Noto...mia! la Cattedrale -Architettura ed Urbanistica del Centro Storico- 1976-1995, Sicula Editrice netum, Noto (Siracusa), 1996LencznerD,WarrenDJN: In situ me a surement of Long term Movements in a Brick Masonry Tower Block. Proceedings of the 6th IBMaC, Rome, 1982; 1467-1477Scotti A: L'età dei Borromei inMonza. In Il Duomo nella storia e nell'arte, Electa, Milano, 198

Measurement of Grout Injection Efficacy for Stone Masonry Walls

For nearly a century, cementitious materials have regularly been injected into masonry structures in attempts to rehabilitate and retrofit them. Typical subjects for this treatment are multiple-leaf, stone walls characterized by poor bonding between external and internal leaves, presence of voids, lack of adhesion between the mortar and the stones, poor cohesion of mortar in the joints and in the rubble infill, possible presence of dry walls in the load bearing system. Unfortunately, most of this has been done without the ability to measure the success of the intervention. Though important progress has been made for establishing potential grout flow through extremely fine material, little is known on the efficacy of treatment in heterogeneous stone walls. The experimental work presented in this paper provides a contribution in establishing a laboratory correlation between visual verification and ultimate resistance, through the assessment of a material groutability and the determination of compressive strength.The research was financially supported by MURST and CNR-GNDT

Assessment of the St. Giusta Church in Bazzano after the L’Aquila earthquake on April 6, 2009

On April 6th 2009 an earthquake with a moment magnitude of 6.3 Mw hit the centre of Italy and especially the historical city of L’Aquila, causing the collapse of many buildings both modern and historic. An overview of the historical cultural heritage showed that the constructions built properly many centuries ago, although the strong seismic events of the past, did not collapse during this last event. It is the case of St. Giusta church in Bazzano, built in the 13th cent and one of the most beautiful churches of the area. St. Giusta, already hit by different historic seismic events, had serious damages during this last earthquake to the facade, with the collapse of the bell tower, to the columns and to the pillars. The paper will report the first investigation of damages carried out soon after the earthquake, the individuation of the mechanisms of failure and of their causes, the emergency provisional structures realized by the fire brigade and the characterisation of the masonry quality through non-destructive tests (flat-jack, sonic, radar and thermography)

Seismic Vulnerability of Historic Centers: A Methodology to Study the Vulnerability Assessment of Masonry Building Typologies in Seismic Area

A methodology of investigation and diagnosis on the built patrimony of historic centres in seismic areas is presented with the aim of collecting an extensive knowledge on the structural typologies and behaviour of historic masonry buildings. This investigation is also the base for the prevention and/or repair of damages caused by earthquakes. Small historic centres or residential buildings in larger centres have been considered for long time as “minor architecture”, but they are meaningful testimonies of the local cultural heritage and express the evolution of a society and of its cultural identity. The results of the investigation carried out on different Italian historic centers, allowed also a critical review of the reliability of the analytical models and of the effectiveness of the repair techniques applied in the past decades. The guidelines emerging from the research results are here presented. A “minimal” diagnostic investigation program is also suggested, in order to support the designers in their projects and to set up appropriate mathematical models to study the vulnerability of the structures

The Basilica of San Vitale in Ravenna: Investigation on the current structural faults and their mid-term evolution

A finite element model was developed to analyze the Basilica of San Vitale in Ravenna (Italy), a Byzantine building which suffers diffused cracking and excessive deformation, mainly as a consequence of complex architectural vicissitudes (extensions, demolitions …) and ground settlements. In the structural analyses, account was taken of permanent loads (self-weight), boundary displacements increasing in time, and seasonal thermal changes. Thanks to previous topographical surveys of part of the building, to chemical and mechanical investigations, the geometry of the Basilica and the main physical properties of the materials are reasonably well defined. The geometric model does not virtually neglect any structural element and accounts for the lack of symmetries in the building. Because of the complexity of the geometric model, a simplified (linearly elastic, isotropic) constitutive law had to be assumed to keep the computing time within reasonable limits. Accordingly, the performed analyses constitute only a first step toward the understanding of the structural behaviour of the Basilica, as the adopted constitutive law can only partially explain the surveyed crack pattern, which is influenced by the brittleness and the anisotropy of the constituent materials

Stress analysis of the Byzantine Basilica of San Vitale in Ravenna: evaluation of its current state and mid-term predictions

A finite element model was developed to analyze the Basilica of San Vitale in Ravenna, a Byzantine building which suffers diffused cracking and excessive deformation. In the structural analyses account was taken of permanent loads and ground settlements increasing in time. The tensile stresses predicted by a linear elastic stress analysis agree with most of the observed cracks. Assuming the ground settlements to increase at the currently estimated rate, the stresses in several parts of the Basilica might seriously endanger the stability of the building during the present century