Structural Laboratories
There are two Structural Engineering Laboratories within the combined Geotechnical and Structural Engineering group. The labs are situated either side of the main foyer of the Cassie building. On one side we have the NUROLF (Newcastle University Rolling Load Facility). On the other side of the foyer we have the heavy structures laboratory.
Heavy Structures Laboratory
This laboratory has a set of reaction frames (a bit like a very big mecano set). It has a solid reinforced concrete floor, 1.5m thick, to which the reaction frames can be bolted. Loads can then be applied to the test specimens using hydraulic actuators. Data is acquired using computer based systems linked to various transducers.
This photograph shows a concrete bridge that is reinforced with disused tram rails from the city of Liverpool. It is under test in one of the reaction frames (blue) and load is applied using the actuator (yellow).
NUROLF Laboratory
The head of the Structural Engineering group, Professor John Knapton, has left Newcastle University to further his career in Consultancy and writing. The Structural Engineering group has been combined with the larger Geotechnical Engineering group. The combined group is now headed by Professor Colin Jones.
Work on the NUROLF facility is now in abeyance and a study has been undertaken to decide the future of this laboratory.
The NUROLF laboratory is a unique facility for the full scale testing of pavement design. The pavement area is built into a test pit 9m x 2m x 1m deep. Into this we can build a complete pavement structure. This pavement is then trafficked using an ex drain cleaning vehicle, whose axle loads can be varied by altering the liquid levels in the vehicles tanks. The vehicle is electrically driven through the vehicles existing transmission imparting a realistic acceleration and deceleration loading pattern to the pavement. Permanent movement of the pavement is recorded using an array of linear transducers linked to a computer based data acquisition system. The data is then processed by software to give a graphical interpretation of pavement deformation.
Permeable Pavements
The latest tests carried out have investigated permeable paving structures. The problem with standard pavement and road structure design is that any rainwater falling on the surface must be drained from the surface quickly. Standard drainage systems move water to rivers very quickly which can cause problems with river levels.
The pavement structure under test was designed to detain water in a tanked area under the surface. This water could then be drained at rate that would not cause environmental problems. The pavement structure must also be able to sustain trafficked loads.
The test pit was lined with a waterproof liner.
The test pit was then filled to a depth of 400mm with a river washed aggregate.
A laying course of screeded sand was then applied to a depth of approximately 30-50mm. Two types of sand were to be considered, one a coarse crushed grit (red) and the other a standard laying course sand (brown).
Finally a specially shaped paving block was layed as the pavement surface. These blocks had larger spacers than a standard concrete paving block which would allow increased drainage to the underlying layers.
This structure was then tested for it's drainage characteristics and it's ability, whilst saturated, to perform as a trafficked pavement.
The pavement proved a success. The structure was able to drain water from the surface at a rate far in excess of that required. It also proved durable under sustained traffic loads.