Coupling effect between masonry spandrels and piers

In-plane performance of masonry load-bearing walls was tested in a quasi-static fashion by loading individual brickwork perforated walls with constant normal force and increasing lateral force. Fifteen full-scale unreinforced frames were constructed by professional bricklayers, from ordinary bricks and lime-mortar according to ancient techniques, so as to be representative of historic masonry. Each wall was subjected to two monotonic loadings (with unloading), up to the full drop-off in the stiffness and complete development of the kinematic mechanism. The specimens exhibited significant overstrength with respect to the strength provided by the masses and high deformation capacity, which are not adequately represented by code provisions for analysis of ancient masonry buildings. The overstrength is here described by several key parameters, namely: (1) Level of coupling piers by spandrels, (2) virtual work done by interlocking and friction forces, (3) and maximum tensile stress in the top spandrel and nodal panels. The paper attempts also to calibrate the behavior factors (q) for masonry frames that are not overly conservative, as code-prescribed q-factors are. Thus, another key issue in the paper is to derive q-factors directly on the basis of the measured values to reproduce the overstrength, allowing for the normal force in the piers and the masonry texture of the wall.

[1]  Paolo Foraboschi.  On the seismic analysis of masonry arch bridges , 2001 .

[2]  Julian J. Bommer,et al.  The Influence of Strong-Motion Duration on the Seismic Response of Masonry Structures , 2004 .

[3]  Christoph Butenweg,et al.  Modelling methods of historic masonry buildings under seismic excitation , 2006 .

[4]  Maria Rosa Valluzzi,et al.  Behavior and modeling of strengthened three-leaf stone masonry walls , 2004 .

[5]  Nelson Lam,et al.  EXPERIMENTAL INVESTIGATION OF UNREINFORCED BRICK MASONRY WALLS IN FLEXURE , 2004 .

[6]  M. Geers,et al.  An enhanced multi‐scale approach for masonry wall computations with localization of damage , 2007 .

[7]  Roberto T. Leon,et al.  Analyses of a Two-Story Unreinforced Masonry Building , 2006 .

[8]  Paolo Foraboschi.  UnReinforced and FRP-reinforced masonry perforated walls: experimental and theoretical analyses , 2007 .

[9]  Paolo Foraboschi,et al.  Strengthening of Masonry Arches with Fiber-Reinforced Polymer Strips , 2004 .

[10]  Haluk Sucuog.  PERFORMANCE EVALUATION OF A THREE-STOREY UNREINFORCED MASONRY BUILDING DURING THE 1992 ERZI0 NCAN EARTHQUAKE , 1997 .

[11]  Mervyn J. Kowalsky,et al.  Compressive Behavior of Unconfined and Confined Clay Brick Masonry , 2004 .

[12]  Guido Magenes,et al.  Testing of Masonry Structures for Seismic Assessment , 1996 .

[13]  Paolo Foraboschi.  Strength assessment of masonry arch retrofitted using composite reinforcements , 2001 .

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

[15]  Siro Casolo,et al.  Modelling the out-of-plane seismic behaviour of masonry walls by rigid elements , 2000 .

[16]  K. Jagadish,et al.  Flexural bond strength of masonry using various blocks and mortars , 1996 .

[17]  G. Pande,et al.  A comparative study on the approximate analysis of masonry structures , 1998 .

[18]  Andreas J. Kappos,et al.  Evaluation of Simplified Models for Lateral Load Analysis of Unreinforced Masonry Buildings , 2002 .

[19]  Paulo B. Lourenço,et al.  Cyclic behaviour of stone and brick masonry under uniaxial compressive loading , 2005 .

[20]  Nelson Lam,et al.  Cyclic testing of unreinforced masonry walls in two‐way bending , 2007 .

[21]  Frieder Seible,et al.  Seismic Response of Full‐Scale Five‐Story Reinforced‐Masonry Building , 1994 .

[22]  Sergio Lagomarsino,et al.  DAMAGE MODELS FOR THE SEISMIC RESPONSE OF BRICK MASONRY SHEAR WALLS. PART II: THE CONTINUUM MODEL AND ITS APPLICATIONS , 1997 .

[23]  Luigia Binda,et al.  RILEM TC 127-MS: Non-destructive tests for masonry materials and structures , 2001 .

[24]  Keith Webster.  TEXT IN ENGLISH , 2000 .

[25]  Haluk Sucuoğlu,et al.  Performance evaluation of a three-storey unreinforced masonry building during the 1992 Erzincan earthquake , 1997 .

[26]  Miha Tomaževič,et al.  Verification of seismic resistance of confined masonry buildings , 1997 .

[27]  Arturo Tena-Colunga,et al.  Seismic Evaluation of Unreinforced Masonry Structures with Flexible Diaphragms , 1992 .

[28]  Michel Bruneau,et al.  State-of-the-art report on seismic performance of unreinforced masonry buildings , 1995 .

[29]  Claudio Modena,et al.  Experimental evaluation of the ductility of a reduced-scale reinforced masonry building , 2001 .