Different FEM models of reinforced concrete frames stiffened by infill masonry for lateral loads

Abstract

The aim of the paper is to introduce how to model more accurate masonry infilled reinforced concrete frames with commercially available FEM software. We developed some numerical models. One question is how to model the infill masonry for monotonic increasing lateral load? Three different numerical models were investigated. The simplest model is the equivalent diagonal strut model, where the masonry wall is replaced by a compressed diagonal strut. The next model is the orthotropic surface model, where the masonry wall is taken into account as a membrane or shell surface. Between the RC frame and the boundary of the surface are modelled with special spring and contact elements. The last model is called "suggested sophisticated model", where the bricks and the mortar layers are separately modelled. The brick is taken into consideration as an orthotropic membrane element, while the mortar layers are substituted with short perpendicular and diagonal equivalent compressed struts. In case of all models small displacements are assumed. We give the necessary data to the material properties in accordance with Eurocode 6. In this paper "only" one numerical example is presented to demonstrate the operability of the different models. In the next step the practical usability and the verification with experiment results of the different models will be presented in another article.Keywords masonry infilled RC frames · numerical modelling of infill masonry wall · material characteristics of the masonry infill István Haris

Comparison of Experimental and Analytical Results on Masonry Infilled RC Frames for Cyclic Lateral Load

“…In this main part of the article we present numerical results of different finite element [14] models.…”

“…In this study we utilize the experimental results of [13,16] and [17] to compare with and verify the numerical results received by "Mesh surface model" and "Suggested sophisticated model", which were defined in [14] (under monotonic increasing lateral load).…”

“…By the evolution of the softwares using in structural design process many analytical and numerical models and results [14,22,24,27,28] were published. Above all many experimental results also were presented in connection with the masonry infilled steel frames [30,35] and concrete frames [4,6,7,23].…”

“…The constitutive equations of the masonry infills are based on the models were introduced in [14] and [15], but modified by the theories of continuum damage mechanics. In the theory of damage mechanics the main goal is to evaluate the description of the micro cracks due to mechanical loads.…”

“…To describe and specify the behaviour of the masonry infilled concrete frames for cyclic lateral loading an experimental research was started at BME in Hungary. At the beginning different finite element models had been worked out [12,14] to describe the behaviour of the infilled frames under lateral loading. A bilinear stress-strain relationship was suggested for the masonry wall, to take into consideration the infills in the RC skeleton.…”