Simplified Mechanical Model to Estimate the Seismic Vulnerability of Heritage Unreinforced Masonry Buildings

Traditional or historic masonry structures occur in large populations throughout the world, particularly in preserved historical city clusters. Being non-engineered and aging these structures are in urgent need of assessment and seismic repair/rehabilitation. However, traditional masonry presents important challenges to computational modeling, owing to complexity of structural system, material inhomogeneity, and contact interactions that collectively can only be addressed through detailed 3D nonlinear representation. In this article, a simple performance assessment model is developed in order to address the need for preliminary assessment tools for this class of structures. The objective is to be able to rapidly identify buildings that are at higher risk in the event of a significant earthquake, potentially justifying a second round of more detailed evaluation. The proposed model defines the characteristics of a Single Degree of Freedom representation of the building, formulating consistent 3D shape functions to approximate its fundamental mode of vibration considering both in-plane and out-plane wall bending as a result of insufficient diaphragm action. Parametric expressions for the dynamic properties are derived in terms of the important geometric, material, and system characteristics, and are used to express local demand from global estimates. Acceptance criteria are established both in terms of deformation and strength indices to guide retrofit. An application example of the proposed assessment methodology is included to demonstrate the ability of the model to reproduce the essential features of traditional masonry buildings under seismic action.

[1]  S. J. Pantazopoulou,et al.  SIMULATION FOR SEISMIC ASSESSMENT OF TRADITIONAL HOUSES IN THE HISTORICAL CORE OF THE CITY OF XANTHI BEFORE AND AFTER NON-INVASIVE STRUCTURAL INTERVENTIONS , 2011 .

[2]  S. BRODETSKY,et al.  Theory of Plates and Shells , 1941, Nature.

[3]  R. Clough,et al.  Dynamics Of Structures , 1975 .

[4]  Serena Cattari,et al.  TREMURI program: An equivalent frame model for the nonlinear seismic analysis of masonry buildings , 2013 .

[5]  Rui Pinho,et al.  DEVELOPMENT AND VERIFICATION OF A DISPLACEMENT-BASED ADAPTIVE PUSHOVER PROCEDURE , 2004 .

[6]  Anil K. Chopra,et al.  A modal pushover analysis procedure for estimating seismic demands for buildings , 2002 .

[7]  Fulvio Parisi,et al.  Non-Linear Seismic Analysis of Masonry Buildings , 2010 .

[8]  Amr S. Elnashai,et al.  Design Methodology for Seismic Upgrading of Substandard Reinforced Concrete Structures , 2007 .

[9]  John B. Mander,et al.  Seismic performance of an unreinforced masonry building: An experimental investigation , 2009 .

[10]  Serena Cattari,et al.  PERPETUATE guidelines for seismic performance-based assessment of cultural heritage masonry structures , 2014, Bulletin of Earthquake Engineering.

[11]  Stavroula J. Pantazopoulou,et al.  Seismic response of traditional masonry buildings: Parametric study and evaluation , 2009 .

[12]  Gian Michele Calvi,et al.  In‐plane seismic response of brick masonry walls , 1997 .

[13]  R. Oppermann.  Strength of materials, part I, elementary theory and problems , 1941 .

[14]  S. Timoshenko,et al.  THEORY OF PLATES AND SHELLS , 1959 .

[15]  C. Şimşir,et al.  OUT-OF-PLANE DYNAMIC RESPONSE OF UNREINFORCED MASONRY BEARING WALLS ATTACHED TO FLEXIBLE DIAPHRAGMS , 2002 .

[16]  Cheng Yu Wu,et al.  The seismic response , 1996 .

[17]  Paulo B. Lourenço,et al.  Abbreviated Title : Homogenised limit analysis of masonry , failure surfaces , 2007 .

[18]  Anil K. Chopra,et al.  Dynamics of Structures: Theory and Applications to Earthquake Engineering , 1995 .

[19]  Vincenzo Gattulli,et al.  Structural performance of the historic and modern buildings of the University of L’Aquila during the seismic events of April 2009☆ , 2010 .

[20]  E. Vintzileou,et al.  Seismic behaviour of the historical structural system of the island of Lefkada, Greece , 2007 .

[21]  Aw Page,et al.  THE BIAXIAL COMPRESSIVE STRENGTH OF BRICK MASONRY. , 1981 .

[22]  C. Arya.  Eurocode 6: Design of masonry structures , 2009 .

[23]  Amorim Varum Humberto.  Seismic Assessment, Strengthening and Repair of Existing Buildings , 2003 .