Design and free vibrations of a large temporary roof FRP structure for the Santa Maria Paganica church.. – CICE 2012

Proceedings of CICE 2012 6th International Conference on FRP Composites in Civil Engineering - Rome, Italy, 13-15 June 2012

Abstract
Presented in this paper are the design approach, construction (assembly) and free vibration measurements for a Pultruded Fibre Reinforced Polymer (PFRP) temporary structure built to protect the partially collapsed Santa Maria Paganica Churchin L’Aquila, following the devastating earthquake of 6.3 magnitude on 6thApril 2009. To accommodate future restoration work, a freestanding rectilinear frame structure of up to 30 m in height, and covering 1050 m2 was executed using standard (‘off-the-shelve’) sections of PFRP. Strut members are built-up of channel sections using stainless steel bolted connections. Frame joints use conventional bolting and gusset plates of a FRP material made by the bag molding process. The design approach checks for Ultimate Limit States with internal forces and moments determined by both linear and non-linear analyses for loads to account for live actions from earthquakes, wind and snow. Because there is a lack of accepted design recommendations the final detailing provides a conservative (safe) engineered solution. The exceptional size and complexity of the L’Aquila structure (having 8.5 tonnes of FRP) is enabling researchers, for the first time, with an all-FRP structure to measure dynamic parameters such as, natural frequencies, damping ratios and vibration modes. Reported are dynamic results from an interferometry measurement technique, which are compared with computational predictions from finite element analyses using the Strand 7 finite element code.

Keywords: FRP construction, Design, Field application, Free vibration dynamics