M-DEM simulation of seismic pounding between adjacent masonry structures.

Seismic damage due to pounding between adjacent buildings is often observed after significant earthquake events in old urban centers and globally recognized as a potential trigger for complete collapse. This is relevant for unreinforced masonry (URM) structures, which are particularly vulnerable to horizontal actions and seldom feature appropriate seismic detailing. Quantifying pounding damage between dynamically interacting URM buildings, however, is a challenging task, the details of which are difficult to simulate through analytical modeling alone. Numerical simulation of pounding failures, on the other hand, involves impact, separation and re-contact phenomena that often require advanced 3D micro-modeling strategies, often entailing a high computational expense that is not feasible when modeling the coupled seismic response of multiple buildings. To enable simulation of pounding damage in URM structures with relatively low computational cost, this paper investigates the use of a recently developed Macro-Distinct Element Model (M-DEM) approach. To this end, a M-DEM is herein used to simulate the shake-table biaxial pounding response of two dynamically interacting stone building prototypes, tested within the framework of the Seismic Testing of Adjacent Interacting Masonry Structures project sponsored by the Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe. Numerical results were obtained before the experimental test and then subsequently evaluated against the experimental results. The M-DEM predictions satisfactorily reproduced the measured base shear and interface opening, although they underestimated the floor displacement demand, especially in the transversal direction. Building on these encouraging outcomes, a post-test refined M-DEM model was also developed, and results are discussed alongside the lessons learned and proposed enhanced strategies to improve the quality of predictions. [ABSTRACT FROM AUTHOR]