A strain measurement model using a limited number of sensors for steel beam structures subjected to uncertain loadings

The maximum stress of a structural member has been extensively adopted as a safety assessment indicator in structural health monitoring. Due to construction errors in the field and changes in the loading conditions during or after construction, it is impractical to accurately predict the location and magnitude of the maximum strain of a member a priori. To avoid the dependency of strain sensing methods on information of the structural and loading conditions, this paper proposes a strain distribution measurement model for steel beam structures subjected to uncertain loadings with uncertainties in magnitudes and shapes. With strains measured from a limited number of sensors, a general form equation of the strain distribution is determined for the estimation of the strain distribution. The performance of the strain distribution measurement model is verified by comparing estimated strain values from the proposed method and measured strains directly from fiber Bragg grating sensors or electrical strain gauges during static loading tests on single- and multi-span beam structures.