Street Utility Poles – analysis, modelling and testing:

MJ Civil Engineering has the capability to carry out detailed analysis and modelling of a variety of poles and fixtures. This can, in many instances, significantly reduce or even eliminate the need for extensive and costly prototype testing.

An example of this was the analysis and assessment of an adapted slip-base frangible pole. The pole is designed to have a sliding base plate mechanism which dissipates the force of any significant impact before the eventual failure of the pole. This frangible approach is becoming common in the design of street furniture, so as to minimise harm to the occupants of a vehicle in the event of a traffic of an accident. 

The design must also ensure that the fixing remains stable and the base does not prematurely slip in normal conditions when subjected to forces such as wind .

The above video clip shows the modelled pole being having a force applied to simulate a vehicle impact. An interesting point is that the forces in the pole are dissipated through the initial base slip, so the pole firstly sides then topple away from the impact, rather than the more traditional rigid approach, where the pole would hinge at the point of impact with a high probability of the section of pole above the hinge point falling onto the vehicle.

The lower video clip shows the action of the baseplate in more detail, firstly the sliding of the pole baseplate across the mounting plate before buckling.

Despite the expense of the intricate modelling there are significant savings to the manufacturers with respect to time and testing costs through the significant reduction in number of prototype tests required for code acceptance, especially where the product is to be installed populated areas, where public safety is paramount.

MJ Civil Engineering has also been involved in implementing laboratory prototype tests of poles and brackets, some of which have been carried out to destruction. Where appropriate, the results of the tests have been compared with those from prior analytical modelling. This has made it possible to calibrate the model for use in future analysis of similar elements.

The lower illustration indicates the models predicted movement relative to the original position shown by the red outline.

This predicted movement from the modelling was then compared against a physical test featured in the photographs to verify / calibrate the model.