Effectiveness of different base isolation systems for seismic protection: Numerical insights into an existing masonry bell tower

Ahmad Basshofi Habieb, Marco Valente, Gabriele Milani*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)


Recent earthquakes in Italy have emphasized the high seismic vulnerability of historical masonry constructions and the need of effective retrofitting interventions. This paper investigates the possibility of improving the seismic performance of a historical masonry bell tower using different types of commercial isolators: High Damping Rubber Bearing (HDRB), Lead Rubber Bearing (LRB) and Friction Pendulum System (FPS) Isolator. Detailed three-dimensional (3D) finite element (FE) models are created to characterize the behavior of the three types of isolators. Then, an Abaqus User Element (UEL) is used to represent the 3D behavior of the isolators for global seismic analyses of isolated structures. The results of cyclic shear analyses show that the proposed UEL model can accurately predict the behavior obtained through detailed 3D FE models. Non-linear dynamic analyses are performed to investigate the seismic response of the historical masonry bell tower in the original and base-isolated configurations subjected to moderate-to-high seismic actions: moreover, the effects of near fault earthquakes are analyzed. The results obtained from the numerical simulations show that the HDRBs do not ensure an adequate seismic protection of the masonry bell tower in terms of damage patterns and top displacements. On the other hand, the LRBs and FPS isolators are very effective in reducing the earthquake effects on the masonry tower: residual displacements are negligible and the isolator displacements are limited. In case of near fault earthquakes, an isolation system with higher damping and larger dimension is required to reduce the drifts of the tower and to accommodate the large displacements of the isolators.

Original languageEnglish
Article number105752
JournalSoil Dynamics and Earthquake Engineering
Publication statusPublished - Oct 2019
Externally publishedYes


  • Abaqus user element
  • FE model
  • Masonry bell tower
  • Near fault earthquake
  • Non-linear dynamic analysis
  • Seismic isolation


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