ROCKFALL PROTECTION DESIGN TESTING IN NEW ZEALAND

The design and build of a Modular Rockfall Protection Wall (MRPW) for the Kaikoura Earthquake Response project was a team effort driven by the North Canterbury Transport Infrastructure Recovery (NCTIR); including Fulton Hogan, Stahlton Engineered Concrete and Geofabrics.

The main challenges facing the design team were space and time - they needed a rockfall protection solution to fit within the narrow coastal corridor and they needed it quickly. The team worked together to develop a practical solution using materials readily available on site – a key element being the concrete blocks, which are a modified version of the more than 7,000 concrete blocks that have been used to build a new sea wall along parts of the corridor.  Adding in some research on rockfall protection walls, the team developed a new configuration that they thought would meet the needs of the project.  The next challenge was to demonstrate to themselves and to key stakeholders that the solution actually worked.  The dynamic nature of rockfall means that it is not that easy to predict the performance of the wall with a set of mathematical equations or computer models.  For this reason, the team recognised the need to test the wall under real impact loading conditions.     

Holmes Solutions undertook a full scale, dynamic impact testing of the solution.  With limited test literature available, a full review of national and international standards was required to identify an appropriate benchmark for product validation.  Once identified, Holmes Solutions developed a test programme capable of assessing the impact of a full scale install with 750 kilojoules (kJ) of energy (ie. approx. 25% more energy than a 36,000 kg truck and trailer travelling at 80 km/hr impacting a safety barrier). With the test sample installed at their impact test facility, the next step was to commence the test programme.  Watch the veido below to see the outcome. 

The results speak for themselves.  After multiple impact tests, the Modular Rockfall Protection Wall met the test programme required, enabling confidence in its future use.  A special thanks to Eliot Sinclair who captured the tests using their Leica P40 with 3D Reshaper software and drone. 

This story was originally published by Holmes Solutions.