Assessment of seismic design provisions for confined masonry using experimental and numerical approaches

Abstract Experience of designing buildings with structural masonry walls and masonry non-structural elements using Codes CR 6-2006 [15a] and P 100-1/2006 [16a], that were developed based on design principles and rules of Eurocodes adopted in Romania SR EN 1996-1-1[13] and SR EN 1998-1[14], revealed the need of some additions and corrections of texts. These interventions made by developing Codes CR 6 -2013[15] and P 100-1/2013[16], which we can characterize synthetically as follows: - Are aligned with the Structural Eurocodes principles but correcting some identified deficiencies. - Resume some previous provisions of national regulations that lack in Eurocodes - Introduce the results of recent theoretical and experimental research - Provide practical application rules, simple and explicit, accompanied by “Commentary” and “Design examples” The communication exposes and justifies synthetically the following new approaches introduced in the 2013 editions of the two regulations: Modification of the methodology for the partial safety factors (γM) and for establishing the minimum necessary strength values of masonry. Additions and explanations of the design rules for unreinforced and confined masonry subjected to combined axial compression and flexure and to shear loading.

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Classification and seismic fragility assessment of confined masonry school buildings

Bulletin of Earthquake Engineering ◽

10.1007/s10518-021-01061-9 ◽

2021 ◽

Vol 19 (5) ◽

pp. 2213-2263

Author(s):

Ahsana Parammal Vatteri ◽

Dina D’Ayala

Keyword(s):

Seismic Design ◽

Field Investigation ◽

Critical Parameters ◽

School Buildings ◽

Seismic Zone ◽

Social Infrastructure ◽

Seismic Behaviour ◽

Building Stock ◽

Confined Masonry ◽

N2 Method

AbstractSchool buildings being a critical social infrastructure, assessment of their seismic behaviour is of utmost importance in ensuring safe schooling facilities in locations of high seismicity. This study presents two important aspects in analysing any existing building stock for seismic behaviour: the development of an appropriate taxonomy system and an appropriate analytical method to conduct fragility assessment. A detailed desk study of existing schools’ databases and tailored field investigation in Guwahati, Assam, situated in India’s highest seismic zone, reveal that the majority of school buildings can be categorised within the confined masonry (CM) typology. This study discusses first, the addition to the World Bank promoted Global Library of School Infrastructure taxonomy of the specific category relating to CM as to include the buildings under study, which are non-engineered CM buildings with flexible roofs. Identifying the density of confinement and quality of connections as critical parameters for the seismic response of these buildings, varying seismic design levels are defined in relation to these indicators. Secondly, the paper presents an approach for carrying out nonlinear static pushover analysis of these buildings with flexible diaphragms and elaborates on the criteria adopted for determining the performance drift limits in buildings with varying levels of seismic design. Numerical analysis for the capacity assessment of selected index buildings is carried out using a commercial software that enables nonlinear extreme loading analysis. Different failure mechanisms as a function of the level of confinement are identified and the performance range for three damage states for three index buildings is obtained by using the N2 method. The study shows the influence of both choices of performance indicators and intensity measure on the resulting fragility functions. Given the consistency of the educational building stock in Guwahati, the results can be used for investment on retrofit decision making at regional level.

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