Ing. Dave van Vliet
- road construction
- road construction materials
Transition joints and transition structures form the 'bridge' between roads and civil structures. Both types of structure are susceptible to deformation and strong load fluctuations. This can lead to damage and therefore undesirable consequences for traffic safety and/or structural safety.
Transition joints connect roads to viaducts and bridges. They are designed to absorb movement in the structures, and the movement of the traffic that passes over them. Even if a transition joint sustains minor damage (e.g. deformation, fractures, detachment), this can cause serious damage to the civil structure. It can also lead to unsafe situations for traffic. Apart from this, deformation and other damage to transition joints often increases noise levels for traffic passing over them. It is in the interest of road operators, motorists and local residents that the construction and maintenance of the road network is carried out as efficiently and sustainably as possible. Transition joints are, however, at right angles to the direction of traffic movement, which means that maintaining and renovating them is often time-consuming and causes considerable disruption and hindrance.
TNO works to improve the life-cycle performance of transition joints. We develop innovative technical concepts for accelerating the construction and maintenance processes for transition joints. In this context we are working on a joint system with fast assembly/disassembly that can be used in viaducts of average length. The system will cut the cost of maintaining and replacing the joints. Because the work can be done more quickly, nuisance and disruption are reduced. This substantially reduces both the indirect cost of traffic congestion and the direct cost of joint replacement.
If the approach road to a bridge is built on weak or unstable subgrade, this can lead to a difference in height between the road and the bridge. This is due to differential settlement. The run-on slabs that are often used cannot guarantee rideability and safety in the long term. Differential settlement calls for radical maintenance work, which is costly. There are several innovative solutions on the market for construction and renovation. These often remain unused because, without convincing research or practical experience, the level of risk is regarded as too high for public works with stringent requirements for safety and/or sustainability. TNO, in collaboration with Deltares and the private sector, is setting up a 'laboratory' for researching and testing innovative solutions. This involves the entire innovation process, from modelling, laboratory validation and validation in practical trials, to regulations and knowledge transfer.