Title: Settlement of Precast Culverts Under High Fills-Influence Structural Effects of Longitudinal Strains

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Publication: CIA

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Date: 2/13/2011

Abstract:
The Morwell River in Victoria was diverted as part of a project associated with the Morwell Power Station. The diversion required the construction of four conveyor tunnels under high fills (up to 45 metres above base level), with varying foundation conditions. Detailed finite element analyses of each conveyor were carried out before construction, to predict upper and lower bounds for the expected settlement, and maximum differential settlement. These analyses were used to preset the vertical alignment of the culverts, so that the conveyors would have close to a constant grade in the finished structures. The differential settlement predictions were also used to assess the effect of longitudinal strains on the culvert structure, and to size movement joints between culverts, and in the foundation raft slabs. In this paper the predicted settlements are compared with actual measured values, and reasons for discrepancies between these values are investigated, including three dimensional effects. The effect of longitudinal differential settlement on the maximum stresses and joint movements calculated at design time are also compared with those due to the measured settlement.