Evaluating the structural capacity of concrete elements through in-situ instrumentation

The difficulty in predicting the long term load capacity of concrete elements is well documented. Time dependent effects such as creep and shrinkage coupled with varying loading events, particularly during construction, can all have an adverse effect on the long term performance of a concrete structure. This paper proposes a method that utilises in-situ instrumentation to predict the load carrying capacity of concrete members. During the construction of the Engineering building at the National University of Ireland, Galway over 260 sensors were embedded in a number of key concrete elements. The sensors are being continually monitored with the use of automatic datalogging equipment and the data is being used to monitor changes in geometric and material properties along with the subsequent time dependent deterioration of the elements. The paper will illustrate how the in-situ data from the demonstrator building can be used to estimate the real time behaviour of the concrete elements and how these elements might respond to future changes in use and potential retrofitting. A cost analysis will show how such a monitoring system can be used to reduce the uncertainty levels involved when retrofitting concrete buildings.