Dynamic monitoring of buildings as a diagnostic tool during construction phases

Abstract

The paper discusses the usefulness of the dynamic characterization of buildings based on the use of ambient vibration tests at different construction phases. The proposed experimental procedure, integrated with more conventional non-destructive in-situ tests for the estimation of the material mechanical properties, foresees the monitoring of the evolution of the building modal properties during the main construction phases. The monitoring makes it possible to assess the correctness of the construction through comparison with expected trends, and to consider possible countermeasures in case of unexpected behaviours. A case study, monitored during its construction, is presented to show the additional value of information obtained from the proposed experimental approach: (i) tests on the bare frame can be adopted to validate the design numerical model of the structure, in which non-structural elements are neglected in performing ultimate limit state verifications, (ii) the proposed monitoring allows the identification of the infills contribution on the building dynamics, providing useful information to address the interaction problem between structural and non-structural elements that may be detrimental at ultimates, and (iii) trends of resonance frequencies during the construction, validated through numerical applications, constitute an important tool for interpreting data from structural health monitoring system, as well as to establish alert thresholds of demand parameters (e.g. relevant to the building occupancy or structural damage).