Gold Excellence Award
3D Laser Scanning of the Triumphal Arch on the Bridge of Remembrance, Christchurch
Entered by Woods Ltd; NZIS Members: Vanda Kadlecikova and Rowan Hallam
Most, if not all, guests in this room will be familiar with the Bridge of Remembrance over the Avon River located in the heart of Christchurch. Like numerous structures throughout Christchurch, the Triumphal Arch and Bridge of Remembrance were affected by the 2010 and 2011 earthquakes and required to be bought up to 100% building code. Consequently, an enormous amount of additional strengthening needed to be added to the existing arch structure, which, as Historic Places Category 1 meant the strengthening had to fit inside the existing cavities of the arch structure. At 14m high for the major columns and 7m high for the minor columns, the relationship of the internal cavities of each column and arch to the external surfaces was critical. 3D laser scanning by Woods was commissioned to capture the cavities that engineers would use for 3-dimensional structural design.
The judges were impressed with the innovation by Woods to overcome professional and technical challenges in this project. At the commencement of the contract the exact nature, access and layout cavities were not known due to the sealed nature of the structure. The features of each void were only available as each cavity was exposed. An example of such challenges is the platforms that were discovered in the internal cavities would mean scanning from the void top and bottom the point cloud could not join and a gap would exist for the middle third of the voids. Without the ability to tie the top and bottom scans together the accuracies of each scan could not be verified. The intermediary platforms inside the narrow vertical cavities were removed and access provided to the bottom of the 7m and 14m cavities. Another challenge was the data capture down the tall and narrow cavities so they inverted the scanner above the void the top of the arch structure by half a meter on a bespoke bracket which allowed a greater overlap of point cloud and assisted the cloud to cloud registration by sampling a greater volume of data.
An accurate point cloud allowed the designer to proceed with confidence, identify design clashes, confirm the ability to build, and demonstrate the available space to manoeuvre the structural steel into place. Vanda Kadlecikova carried out Site scanning and led the data processing, while Rowan Hallam was responsible for project Planning and set up, as well as data processing and delivery.
Silver Excellence Award
Waterview Tunnel – The Northern Monitoring Zone
Entered by Well Connected Alliance ( NZ Transport Agency, Fletcher Construction, McConnell Dowell Constructors, Parsons Brinkerhoff, Beca Infrastructure, Tonkin & Taylor and Obayashi Corporation)
NZIS member Michael Cutfield (Fletcher Construction)
Continuous Real time monitoring is a complete Surveying and Information Communications Technology system designed to detect movements of 2mm or greater in the built environment. Measurements can be viewed as they happen and are processed and presented in a form that can be interpreted by anyone. NZTA required this monitoring regime as part of the Waterview connection tunnelling project to provide immediate alerts of structural movement and safety risks and immediate identification of trends and future risks.
The Northern Monitoring Zone was designed as an array of survey marks which span across both tunnels for the northern 400m of the twin tunnels and the real-time monitoring allows the tunnel boring machine operators to monitor surface changes. With 55,000 vehicle movements pre day Great North Road is the busiest local government owned road in the country and is also where Alice is the shallowest and in the weakest soil. Real-time monitoring of this area was important for public safety and early detection in case of ground failure. Alice costs the project around $100k per day to operate and the continuous real-time monitoring ensures no delays.
Level control came from 10 benchmarks over the length of the project, 2 of those marks were on bridge columns/piles, and 8 were drilled into the bedrock - in one case, this was 28m deep. These were levelled many times with a precise level and for the purpose of the Continuous monitoring, the primary level control is checked against the local secondary control on a daily basis.
Survey marks needed to be measured by conventional methods but situated so they didn’t impede the public’s enjoyment of the area. On the road, specialised prisms were ordered that looked like normal cats eyes. A total station needed to be on site 24/7, so a protective wooden box was fabricated that provided protection from the weather and discouraged vandals. The real-time monitoring was supported by daily precise level monitoring. A laptop received the readings and needed to be within continuous radio range so it was kept in the security guard’s hut.
Using the Trimble 4D monitoring suite a web portal provided access to live updates. The major challenges that the Alliance dealt with were keeping Alice’s operators, design verifiers, the local council and the client informed of any immediate ground movements; establishing control that is fixed and will not move with the changing seasons; transferring the primary control to be within range of the total stations, keeping survey costs affordable; and monitoring in public areas. The system has since been implemented in other parts of the project with success and is a testament to the professional input from Michael Cutfield.
Merit Excellence Award
850 Cameron Road, Tauranga
Entered by Mike Stott, Lysaght Consultants
Lysaght Consultants played an integral part of a recent site development at 850 Cameron Road, Tauranga. 850 Ltd purchased a site that was vacant and being used as a free carpark by Hospital staff and visitors to the hospital. There were numerous hurdles to cross to bring this to a successful multi-use development. During the design phase, Lysaght’s obtained a land use consent to allow continued operating as an unofficial car park – even though no fees were being collected from the site.
One of the significant risks for 850 Ltd was that any redevelopment of the site creating vehicle movements over and above the existing residential movements would require the intersection at 18 th Avenue Ave and Cameron road to be signalised. Cameron Road would also have to be widened to accommodate the new signals. Early pricing of signals and road widening was priced in the order of 1 million dollars.
Fortunately, Lysaght’s established working relationship with Tauranga City Council helped negotiate a cost share agreement between Council and 850 Ltd, because the project would not be viable if 850 Ltd had to foot the entire bill. Limited notified; non-complying; land use and unit title consents completed Lysaght’s planning process.
850 Ltd identified the site as being in a perfect location to build a commercial development that had activities that were complementary to the Tauranga Hospital campus, which is located directly across from the site on Cameron Road. It was determined that the construction of three separate buildings on the site specifically designed to cater for a motel, child care facility, café and associated professional medical suites were going to be the best utilisation of the site.
Lysaght’s engineering team undertook the detailed design of the widening of Cameron Road in conjunction with Traffic Design Group, and the detailed engineering design of the internal services of the development site itself.
One of the major milestones of the development was the signalisation of the 18 th Avenue and Cameron Intersection which needed to be completed and operational before any activity could commence on the site. The delivery time for the road widening was very tight and included construction during the Christmas close-down period. A good working relationship between Lysaght and the contractors allowed the commissioning of the lights to be completed one day before the childcare facility officially opened.