Comparison of equivalent beam models and refined approaches for the modelling of masonry portal frames

Abstract

The recent evolutions in the analysis and design of masonry structures tend to let consider these structures at the same level as the more traditionally engineered materials, namely steel and concrete, as far as it comes to the refinement of the analysis and of the control of the failure modes in the framework of a limit-state design approach. Such an evolution comes together with the development of reliable analysis tools. In this context, the most promising approach whose use could reasonably be generalized in regular design offices for the analysis of full buildings is the use of equivalent beams to model walls and spandrels, resulting in a global frame modelling approach of entire structures. Such models need however to be properly calibrated regarding a large number of aspects such as deformation properties, resistance models, behaviour of the nodes, lintels, spandrels... The proposed paper aims at illustrating such a calibration process. It starts from experimental results achieved at the University of Liege on small clay masonry structures made of two walls connected by a spandrel, with a RC lintel over the door opening and a RC beam emulating the presence of a concrete slab at the first floor level. The tests specimens are then modelled using a refined finite element approach and compared with a frame modelling considering the vertical and horizontal structural elements as equivalent columns and beams.