A nonlinear macroelement model for the seismic analysis of masonry buildings

The macroelement technique for modelling the nonlinear response of masonry panels is particularly efficient and suitable for the analysis of the seismic behaviour of complex walls and buildings. The paper presents a macroelement model specifically developed for simulating the cyclic in-plane response of masonry walls, with possible applications in nonlinear static and dynamic analysis of masonry structures. The model, starting from a previously developed macroelement model, has been refined in the representation of flexural–rocking and shear damage modes, and it is capable of fairly simulating the experimental response of cyclic tests performed on masonry piers. By means of two internal degrees of freedom, the two-node macroelement permits to represent the coupling of axial and flexural response as well as the interaction of shear and flexural damage

Pushover and dynamic analysis of URM buildings by means of a non linear macro-element model

A mechanical macro-element model representative of the in-plane nonlinear behaviour of masonry piers and lintels (with shear-sliding, bending-rocking damage mechanisms and compressive crushing) has been used to realize models of masonry walls and whole three-dimensional buildings. Both for two- and three-dimensional models, several structural analysis procedures have been implemented: non-linear incremental, pushover, modal and non-linear dynamic. The numerical simulation of an interesting quasi-static experimental test on a full scale prototype building has been used as significant validation of the model implemented in the TREMURI code. Pushover analysis permits to obtain the capacity curve of the 3-dimensional building and this result can be used in the Capacity Spectrum Method in order to determine the expected seismic performance. The results can be then verified by time-history non-linear analyses. Finally, a new fast implementation of the Capacity Spectrum Method, according to the inelastic demand spectra approach, is presented: it allows to avoid iterative procedures and it is very effective, in particular, for seismic damage scenario studies, where buildings vulnerability can be described by bilinear capacity curves

TREMURI program: An equivalent frame model for the nonlinear seismic analysis of masonry buildings

The seismic analysis of masonry buildings requires reliable nonlinear models as effective tools for both design of new buildings and assessment and retrofitting of existing ones. Performance based assessment is now mainly oriented to the use of nonlinear analysis methods, thus their capability to simulate the nonlinear response is crucial, in particular in case of masonry buildings. Among the different modelling strategies proposed in literature, the equivalent frame approach seems particularly attractive since it allows the analysis of complete 3D buildings with a reasonable computational effort, suitable also for practice engineering aims. Moreover, it is also expressly recommended in several national and international codes. Within this context, the paper presents the solutions adopted for the implementation of the equivalent frame model in the TREMURI program for the nonlinear seismic analysis of masonry buildings

Analisi non lineare di edifici in muratura con il programma TREMURI

Modelli tridimensionali completi di strutture esistenti in muratura possono essere ottenuti assemblando macroelementi a 2 nodi, che rappresentano il comportamento nonlineare di pannelli in muratura e maschi murari. Questa strategia di modellazione \ue8 stata implementata nel programma TREMURI, con procedure di analisi non lineari statiche e dinamiche che richiedono un onere computazionale limitato. Per mezzo di variabili interne, il macroelemento \ue8 in grado di considerare sia la rottura per taglio-scorrimento e la sua evo-luzione, controllando il deterioramento della resistenza ed il degrado della rigidezza, sia i meccanismi di pressoflessione-ribaltamento, tenendo conto degli effetti della rottura per compressione degli spigoli. I modelli degli edifici in muratura possono essere ottenuti assemblando strutture piane, pareti e solai