Author: David Williams

Scour & Shake: preparing for testing on the large table

Posted on by David Williams
A large aluminium and rubber container with support frames mounted to a large shaking table. Next to it is a dumbell-shaped concrete and aluminium specimen mounted vertically.
Specimen mounted to the table next to the shear stack for fixed base testing.

We’re almost ready to start testing on our large shaking table, for the first of four projects being undertaken in SoFSI as part of the wider European-funded ERIES project. This project, in partnership with a multi-national user group, aims to investigate the effect of river scour on the seismic performance of bridge foundations.

The first stage of testing is a fixed-base test of the specimen mounted directly on the shaking table. This will help to characterise the model so we understand it’s resonant frequencies.

We will then mount the model in sand in our shear stack (laminar soil box) for the main set of tests in April. For these we’ll subject the model to white noise and seismic motions, before excavating increasing depths of sand from around the foundation to simulate scour of the sediment.

A dumbell-shaped specimen made of concrete masses and aluminium bar mounted vertically on a steel surface. Sensors are attached to the central bar.
The 1:15 scale model of a bridge pier, with concrete foundation section, aluminium bar selected to model the stiffness of the prototype bridge pier, and concrete top mass to simulate the load from the bridge deck.

 

Hexapod moves to SoFSI

Posted on by David Williams

The final major piece of equipment has now arrived at SoFSI, with our six degree of freedom shaking table making the move from Queen’s Building to its permanent home in Langford. With decommissioning in Queen’s Building starting in mid-August, the Hexapod was moved and recommissioned at SoFSI by mid-September. The higher pressure and flow rate of the hydraulic system here allows the Hexapod to reach its full triaxial performance of 8g with a 500kg payload. Since moving, it has already successfully been put to use for seismic qualification work.

Small yellow shaking table with blue hydraulic actuators and base plate in position.

First research project underway

Posted on by David Williams

Construction is complete on our first research project at the Soil-Foundation-Structure Interaction Laboratory. This project, which makes use of our 4m deep soil pit, has been under construction since late May. Researchers aim to better understand the interaction between the abutment and backfill of integral bridge abutments.

We are now at an exciting stage in the project, having completed the physical construction, and are now preparing instrumentation ready for testing in August. In total, over 100 tonnes of concrete and sand form the experimental set-up, and this has been a great opportunity to pilot the use of the pit, and hydraulic actuator for the first time.

  • A 4m deep pit, with precast concrete blocks being positioned to form a retaining wall

Shaking table commissioned

Posted on by David Williams

In December the large biaxial shaking table underwent commissioning testing. This involved operating the table for the first time and checking all safety and performance functions, followed by validating its performance against the original specification. It was great to see it in motion and we’re looking forward to the training and using it in anger later this year.

Shaking table installed

Posted on by David Williams

Another major milestone was passed at the end of September as the 30 tonne surface of our biaxial shaking table was lifted into its final position. The four actuators have since been installed around the table, and once the final hydraulic hoses have been connected, physical installation within the facility will be complete. The next significant event will be acceptance testing of the table which is expected towards the end of November, and will mark the final activity before the faculty is handed to the University.

Wide angle view of the yellow painted shaking table with machined surface in position within its pit.
The 6x4m shaking table in position.