Safety analysis for bridge pier under nearby road construction and operation

Abstract

A temporary road underneath a riverine expressway was constructed to accommodate the need of transporting soil for land reclamation. One of the most outstanding characteristics of the new temporary road was that it passed underneath the piers of a continuous reinforced concrete bridge. The additional loads caused by the road construction and later on operation with heavy trucks potentially jeopardized the safety of bridges. The objective of this study was to examine the influence of the road construction and operation on the behavior of bridge piers and foundation piles. In addition, the effectiveness of a retrofit countermeasure of using steel sheet walls for improving the stability of the bridge was studied. A detailed three-dimensional finite element (FE) model, capable of addressing the interactions between pier columns, pile foundations, surrounding soils, and heavy truckloads, was developed to facilitate the analyses. After validating the model with the common analytical M method, the developed model was employed to investigate the behavior of bridge under the combined effects from temporary road loads (i.e., soil excavation load, pavement weight, and heavy truckloads). Field measured data from a tilt health monitoring system were utilized to verify the performance of FE analyses and confirm the performance of the retrofit countermeasure for pier deformation control. The steel sheet walls were found to be effective in increasing the safety of existing bridge piers.