Innovation & Excellence in testing bridge load capacities.
In practice, the elastic load capacity of a structure is usually greater than that predicted from a standard desktop analysis. To address this challenge, VEC introduced an economical bridge load testing and rating system into Australia, which has also resulted in substantial savings on strengthening and/or replacement requirements for clients.
In association with Bridge Diagnostics Incorporated (BDI) of the USA, VEC created a fast and accurate method of developing a ‘calibrated elastic model’, which involves:
- developing an elastic model based on the as-constructed drawings, visual inspection and other documentation of the structure;
- measuring the strain at up to 48 locations on the structure as a truck or other vehicle of known weight crosses; and
- calibrating the theoretical model by adjusting (within recognised limits) member stiffnesses and boundary conditions so that the strains and deformations in the model are matched with the test results.
Once the model has been calibrated, any vehicle load configuration (including design vehicles, permit vehicles or overloads) can be applied with the appropriate live load and dynamic load factors to determine the structure’s actual live load rating.
The system can be used to rate all manner of steel, timber, reinforced concrete and prestressed concrete structures.