A fast modeling approach for numerical analysis of unreinforced and FRCM reinforced masonry walls under out-of-plane loading

Abstract

A new discretized homogenization approach is proposed in this study in order to predict the behavior of unreinforced and FRCM reinforced masonry structures. The proposed approach allows overcoming the common disadvantages of the existing homogenization approaches: (a) being difficult to implement and (b) not allowing to couple the in-plane and out-of-plane actions. Reference experimental results and detailed numerical modeling are used for validation of the proposed modeling strategy. In the proposed model, the elastic cells are linked by homogenized interfaces. The mechanical properties coming from the homogenization procedures are lumped at the interfaces by means of the generic Concrete Damage Plasticity model, allowing easy implementation and avoiding computational issues peculiar to other approaches available in the literature. The new approach shows accurate results in predicting the global behavior and the damage pattern for both unreinforced and FRCM strengthened masonry walls. The results are promising also with a view to be applied for more complex reinforced applications as double curvature masonry structures. INTRODUCTIONThe heterogeneous character of masonry structures, along with their weak behavior under tension, make their analysis a challenging task. The need for introducing a reinforcing system, in order to reduce the vulnerability of masonry structures to seismic actions, adds a further complication in the numerical modeling procedures. A wide overview of the most diffused strengthening techniques used for improving the seismic performance of unreinforced masonry buildings is discussed in [1], which provides as well an insight into the numerical approaches used in literature. In the last five years, the application of fiber composite materials has met successively the requirements defined by guidelines, such as the ones from the International Council on Monuments and Sites. At first, after a successful application of FRP (Fiber Reinforced Polymer) on concrete substrates, the technology started to be applied also on masonry ensuring a marked increase in terms of strength and deformation, along with a relative easy execution [2]- [9]. Its effectiveness has been proved also at buildingscale level, an evidence supported by non-linear numerical analyses on case studies [10].In the case of interventions with FRP, the use of epoxy resins as matrix is able to provide an efficient bond with the masonry substrate. On the other hand, there are some disadvantages in terms of compatibility, as reported in [11]. The main issues are related to damp incompatibility, as the application of epoxies can be unsuccessful on humid surfaces. Also, the system masonry substrateepoxy matrix may be subjected to strain incompatibilities due to different thermal coefficients. Moreover, when applying this kind of reinforcement, the vapor permeability is strongly reduced. The issues are not only related to incompatibility with the substrate, but also to the potential of harm for workers when the epoxies are applied, to its hi...

An Automatic and Fast Procedure for the Numerical Analysis of Curved Masonry Structures

“…In this section, a general overview of the method is provided. The validation and its implementation are deeply discussed in [7] and the interested readers are directed to this research for a point of reference.…”

“…The efficacy of the method has been already described for the case of brick walls loaded out-of-plane, in the unreinforced and TRM-reinforced configuration in [7]. The extension of the method even to curved structures is suitable as the modeling of interfaces with flat 3D elements leads to a full coupling of in-and-out-of-plane actions.…”

A Discrete-Macro-Element-Model for the in-Plane Analysis of Masonry Structures Strengthened by FRCMS

“…Then the challenging problem of the scientific community is to simulate the complex mechanical behavior of unreinforced/strengthened masonry constructions with a limited computational cost and with sufficient accuracy. Is the case of simplified continuum finite element models where the masonry is represented as an equivalent homogenized continuum material [9,10]. Simplified structural macromodels aiming at drastically reduce the computational effort by describing each structural element through a single computational element (macro-element) or a coarse mesh of them, are largely used both in engineering practice and research [11,12].…”

Role of Repeated Seismic Events on the Collapse of Two Calidaria in Rome Dating Back to the Imperial Age

“…The characteristics of the Roman concrete, poor tensile resistance compared with high compressive strength, provide it a quasi no-tension behavior [2] allowing to follow the numerical strategies proposed for vaulted masonry structures [3]. Among the methods currently available from the technical literature, we can mention the modern limit analysis tools based on the static [4][5][6] and the kinematic theorem [7][8][9][10][11][12] but also the recent numerical techniques relying on the Finite Element (FE) method [13][14][15][16].…”