Christchurch Infrastructure Recovery - Beca Ltd

ClientChristchurch City CouncilLocationNew Zealand
ConsultantBecaContractorAnna Collins

Christchurch Infrastructure Recovery

Project Summary

The 2011 earthquake activity in Christchurch cause widespread liquefaction and seismic settlement resulting in considerable damage to the wastewater network. One of the greatest resulting concerns was loss of reticulation grade in the wastewater network (which in turn affects capacity of the pipe). In order to answer the question of how much loss of grade can be accepted before renewal of a gravity pipe is necessary; Christchurch City Council (CCC) implemented a policy which compared the post-earthquake grades of the network with the pre-earthquake grades and the pre-Infrastructure Design Standard grades.

The Challenge

Following the implementation of the CCC policy, it then became apparent that the team needed to find a way of comparing the original grades of the network “pre-earthquake” to the surveyed inverts and grade “post-earthquake”. Other designers had done this comparison by using Excel spreadsheets, but they wanted a visual means of representing the data which could easily be reviewed and form part of the concept design report for a particular project area.

The Solution

They decided to use 12d Model to build two wastewater networks for a particular project area - one to represent the pre-earthquake network and the other the post-earthquake network. The post wastewater network was built using manhole lid and invert data provided by the survey team.
This model was then copied and pre earthquake data taken from the Council GIS maps were inputted to form the pre model. Using 12d Model’s exporting/importing functionality, pre-earthquake grades and inverts were copied from the pre model and included as separate attributes to the post model. Following this, pre and post long sections were plotted using a 12d plot file.


The result was a quick and visual means to assess the loss of grade and settlement within the wastewater network and assist in the design of the network restoration.

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