Sustainability in enhancing the resilience of major route in Wellington

Abstract

Uncertainty in the seismicity of Wellington and climate change were key issues that influenced the design of strengthening of a key arterial route in Wellington. The abstract describes the innovations and technology adopted in the project to strengthen a large retaining wall along the Chaytor Street in Wellington, considering sustainability. Strengthening design was developed for two retaining walls along a continuous 220 m long alignment, along the critical Chaytor Street in Wellington to enhance route resilience. MASW geophysical surveying supplemented with few boreholes were carried out as part of site investigations, reducing traffic disruption and materials costs. Preliminary design option comprised more conventional anchors closely spaced along a surface area of nearly 1000 m2. A sustainability assessment was carried out to select the best sustainable option from many other options to strengthen the walls. The relative importance of the three sustainability pillars (environmental, economic, and societal/functional) were key drivers in selecting the option for strengthening the wall. The strengthening scheme comprising a concrete overlay supported by rock anchors and piles, developed using various models for optimized use of materials like steel and concrete. This option made use of the existing unreinforced and lightly reinforced walls with a new structural overlay, connected at the anchor locations to minimize concrete use. Post-grouted rock anchors were adopted to enhance capacity and reduce construction time and environments issues. The integrated three dimensional model was used to consult with stakeholders, and this digital twin will facilitate meaningful construction input and future asset management.