Re-Evaluation of the Design During Construction with Monitoring Data and Utilization of the Observational Method in Shoring Works

Monitoring studies provide opportunity to compare the target performance of a shoring project in the design phase and its actual behavior during the excavation. This data allows a timely response to the mismatches between the estimated and occurred. Either increase or decrease of the support elements can be considered according to the necessary action. As examples of these actions two shoring projects located in Istanbul were reviewed within this study. The projects consisted of different shoring techniques such as diaphragm wall and soil nailing and monitoring data gave the opportunity to re-evaluate the design during the excavation. Displacements were monitored with inclinometers and reflectometers throughout the gradual excavations. Loadcells were utilized to monitor the anchor loads during the excavation steps. In one project it was necessary to strengthen the supporting system and in the other one monitoring allowed an optimization of the remaining applications. These shoring projects were back-calculated to check the considered soil properties in the design phase. A comparison study was also conducted to see the impacts if observational method was followed in the design phase. Design process of the observational method in shoring works was described. Impacts of the observational method on the cost, duration and environment were discussed.