Ambient vibration test

This paper presents the results of an experimental and theoretical investigation on the Pietratagliata cable-stayed bridge (Udine, Italy). Ambient vibration tests were performed in order to estimate the dynamic characteristics of the lower vibration modes of the bridge. Structural identification is carried out by means of a manual tuning procedure based on finite element models of increasingly accuracy. The analysis allows to improve the description of boundary conditions and mechanical interaction between the bridge components. Results from local dynamic testing are used to estimate the traction on the cables and to assess the integrity of the suspending system of the bridge.

Most of the historical unreinforced masonry structures were built in Bangladesh during Mughal period and British rules. This type of structures is seismically vulnerable and need to strengthen for preserving its historical and cultural heritage value. This study was conducted to collect preliminary information on dynamic properties of old historical unreinforced masonry buildings located in Bangladesh. A series of ambient vibration tests (microtremor records) were performed to evaluate structural dynamic properties (damping ratio, fundamental natural frequency, etc) of three old unreinforced masonry buildings including mosque and educational use occupancy. Microtermor record was taken for 30 minutes for each building. After obtaining microtremor records, random discrete technique was performed to estimate transfer function and relevant characteristics. This paper describes the buildings tested, applied methodologies, equipment used and test results. Based on experimental information, variations of dynamic properties with preliminary influence factors are discussed.

The paper describes the approach followed in the characterization of the structural behavior of the historical masonry church of San Filippo Neri in Macerata, severely damaged and condemned after the Central Italy Earthquake occurred in October 2016. The case study of San Filippo Neri is particularly interesting: first for the historical and artistic importance of the church furthermore for the evidences of recurrent structural damage. The laboratory of Proof and Research on Structures and Materials of Roma Tre University carried out an extensive onsite testing campaign-including geometric survey, flat-jack test and ambient vibration test-in order to investigate the state of the building. Operational modal analysis was used to assess the dynamic behavior of the church; the results of the testing campaign were interpreted and correlated with an accurate finite element model of the construction. The numerical model was finally tuned up based on the experimental results in order to match the dynamic behavior. The aim of the research is to set the first steps for an integrated approach able to fit and combine the results from experimental onsite testing and numerical modelling.