Technology provides tightly connected office and field operations for a single, unified view of the project
The MacKays to Peka Peka (M2PP) project is being built by an alliance made up of the New Zealand Transport Agency, Beca Planning and Infrastructure, and Fletcher Construction. The M2PP Alliance brings together a high performing, integrated team to address this project's complex design, construction, environmental and lifecycle issues. This model of contracting that has been successfully used around the world to deliver complex and challenging infrastructure projects.
The M2PP Alliance is providing consulting, design and construction services for the 18-kilometer [11.2 mile] stretch of expressway that cuts through the Kapiti Coast in New Zealand from MacKays Crossing to Peka Peka. It’s the first of eight sections that will eventually form a larger 100- kilometer [62 mile] expressway called the Wellington Northern Corridor. Sponsored by the NZ Transport Agency, the Wellington Northern Corridor is one of seven ‘roads of national significance’ that the NZ Government has identified as essential state highways which require upgrading to reduce congestion, improve safety and support economic growth.
The $630-million NZD project will deliver approximately 18 kilometers [11.2 miles] of four-lane expressway through Kapiti. The new route will take approximately four years to build and involves moving 3.5 million cubic meters [123 million cubic feet] of earth, including more than 800,000 cubic meters [28 million cubic feet] of peat. In fact, the $52 million earthworks subcontract awarded to Fletcher and their subcontractor Goodmans is the largest contract awarded in New Zealand history to date. With all payments being calculated on volume, one of the big issues being faced by the Alliance was how to manage and account for these movements in an efficient way. This also needed to be managed in conjunction with the survey requirement for building the expressway, its 18 bridges and the 18 kilometers [11.2 miles] of cycle way, bridleway and footpath.
The team adopted the entire Trimble® Connected Site® portfolio, including on and off machine Trimble technology that tightly connected office and field based operations for a single, unified view of the project.
- Reduction in re-work - 3D machine control cut, fill and grade work is accurate the first time
- More effective planning – Faster earthworks planning, reliable production monitoring from 2D and 3D project monitoring to check as-builds and plan mass haul routes
- Removed days (and much confusion) from the billing process - Can now pay earthworks subcontractors with monthly volume reports calculated in Business Center - HCE and VisionLink
- Increased safety - Automatic measurement with 3D machine control on excavators means machines can measure the bottom of a peat dig-out; this eliminates the need for to have a surveyor in a boat measuring manually
- Better modeling and mass haul planning - Can create a subgrade model for the job, add and remove variables and constraints to run mass haul analysis to calculate efficient routes
Excavation work on the M2PP project began in January of 2014 and the road is expected to be open to traffic by 2017. The project has required the compulsory purchase of over 80 homes and businesses and involves building 18 new bridges, creating an end-to-end cycle way, bridleway and walkway, and creating connections to local roads. The expressway travels through ecologically important wetlands, streams and native bush, and the project work includes creating and re-planting over140 hectares [346 acres] of new native plants to mitigate its impact. Every hectare lost or impacted is replaced with over five times its equivalent.
The expressway route also includes several archeological points of interest, and traverses culturally significant Maori land. Because of this special connection, care and consideration is also required during excavation and building phases, and both an archaeologist and an iwi monitor (Maori cultural adviser) are always on site when all new ground is broken.
Connecting Site Processes
With all of the moving pieces in this project, M2PP Survey Manager Will Newall and his team realized early on that streamlined data management and effective communication was going to be critical. The team also wanted a single unified view of the project to track progress and drive productivity across the M2PP initiative. Already a power user of Trimble machine control and GPS, Fletcher Infrastructure began by adopting Trimble Connected Community. The web-based Connected Community is a centralized information management system designed to tightly connect people, sites, processes and devices wirelessly in real time. It essentially provides the two-way data synchronization backbone for the Trimble Connected Site solution.
Using Trimble Connected Site solutions, Newall can communicate in real time with his team and machines on the site. This means his team is using:
- Trimble Site Positioning Systems to collect site data throughout the process
- Trimble Connected office software including Business Center - HCE, VisionLink and Connected Community to create site plans and digital models as well as track earthworks, and
- Trimble GCS900 Grade Control Systems for faster, more accurate earthworks.
“The data workflow for the expressway project works like this: our project design files and 3D models are loaded into Business Center - HCE for data prep,” said Newall. “Then, those files run through Trimble Connected Community, the synchronizer software that sends the information to the cloud; our three base stations are connected to the cloud. Our 3D machine control systems can transfer and receive plans and information whenever we want. If I’m in the office or a pub after work I can hit synchronize and everything is all connected to the cloud and into VisionLink allowing me to see where machines and materials are at any given time. It’s brilliant, and I couldn’t imagine managing a project of this size without it.”
The project was divided into three separate zones approximately six kilometers each: South, Central, and North. The project is being run by Trimble Internet Base Station Service (IBSS) leveraging GNSS base stations. The North Island VRS network (Virtual Reference Station) Network provided high-accuracy, real-time kinematic (RTK) GNSS positioning for the wider area. The base station equipment consisted of a GNSS receiver, GNSS antenna, radio and radio antenna. These receivers enable remote configuration and provide corrections to 12 GNSS-based Trimble Site Positioning Systems. Trimble total station-based Site Positioning Systems are also being used for survey work across the project.
Data Prep, Workflow and Modeling
The team used engineering design packages, including Bentley’s MX platform, as well as Trimble’s Business Center - HCE to create and adjust the 3D models and check volumes of materials across the project site. Newall considers Trimble Business Center - HCE the ‘hub’ of the M2PP operation because it’s where all project data is centralized. He and his team can also efficiently edit, process, and adjust the survey data and 3D model as it changes—such as discovering there is more cut available or that there is an excess of sand, in the northern section of the roadway.
“The beauty is I may be in my office on my fourth cup of coffee, but I can get real time information on materials used and where it’s going as it happens,” said Newall. “I am responsible for making sure that the correct revision of the design is pushed out to the machines so I can say, ‘that is the correct design and it needs to go to that machine.’ And if changes have to be made, I don’t have to hop in the truck to get the site. I’m in constant wireless communication with our people and machines over the Internet.”
Newall points out that CAD files, PDF files and design models are imported into Business Center - HCE for data prep. They are digitized to help the quantities takeoff and cost estimating of how much peat will be removed and sand required for laying subgrade, for example.
“From the 3D design we also create a subgrade model in Business Center - HCE, and that works for us on a couple of different levels: it calculates our volumes first, and then we can determine if we are going to have enough sand for cut and fill,” said Newall. “We’re able to send this to our operators and they can see what they are grading to on their Trimble CB460 control box in the cab of the machine; there’s no offsetting needed. Essentially there’s much less room for error, and they can just go straight to work.”
3D Machine Control Means Going ‘Stakeless’ and Saving Money
The M2PP Alliance equipped several pieces of equipment with the Trimble GCS900 Grade Control System, including: five excavators, three graders, two bulldozers and two compactors. Using digital terrain models, the machine control system uses GNSS technology to compare the position of the bucket or blade to the 3D site plan. Newall can transfer survey controllers’ data and surface model data captured from the machine blades, all remotely from his office.
Newall explains that the Trimble Connect Site solution and 3D machine control systems have been a complete game changer for a number of reasons. One of them is the fact that he has only used a handful of stakes across the 18-kilometer [11.2 mile] project. Initially his team staked about 1.6 kilometers [1 mile] of the expressway, pounding in stakes every 40 to 50 meters. These were used to show where the edge of the earthworks footprint was and to mark where topsoil could be striped. At about $10 per stake, for this small section alone it cost approximately $10,000 NZD. Newall estimates running and managing survey crews and stakes for the entire project would have been well over $150,000 NZD.
Calculating Mass Haul
When it comes to mass haul, the team has a significant advantage using Trimble technology. The team can create a subgrade model for the job, add variables such as areas where the bridges are going, where bridges aren’t yet built, where dump sites are located, and more. Then, Newall can run the mass haul analysis in Business Center - HCE to calculate the most efficient way to move material from place to place within the job site.
“Across the top we have all of our haul roads; we can add new constraints, remove constraints and rerun our routes,” said Newall. “Business Center then recalculates our haul route in about five minutes, whereas before it would have taken as much as two weeks to plug all of those numbers into Excel. On an 18-kilometer expressway project that scenario happens over and over―so that’s a massive savings of time and effort.”
Improved Safety with Automatic Measurements
Because much of the survey and measurement on the job is now done with GNSS and machine control, risk to surveyors has been cut and project safety has improved. For instance, with 3D machine control on his 50-ton excavator, the machine can actually measure the bottom of a peat dig-out to create an asbuilt survey. Previously without machine control, a surveyor in a boat had to get out there with a wetsuit and lifejacket and survey the bottom of the excavation site with a five-meter pole. This alone is a full-time job, because as soon as the peat is removed, operators have to backfill. This is because there's always a risk of collapse with this type of soil composition.
“We had to do that a couple of times because our machines were busy and it's just not good; we lost a surveyor for two full days to that work,” said Newall. “But with 3D machine control I don't have to have a surveyor anywhere near that kind of dangerous situation. The machine does it all, which makes it worth its weight in gold. Now with machine control, our earthworks subcontractor can dig until they get a bucketful of clear gravel at the bottom. Then that's it and it's measuring all the time to create an as built of the bottom.”
Newall attributes significant productivity gains and on the job site and less rework to machine control and the whole Connected Site.
“Instead of removing the stakes every 20 meters for a cross section cut, across the entire project let’s say, with machine control now every single millimeter of the job is in 3D; essentially every single millimeter is cut perfectly, which vastly reduces the potential for rework,” said Newall. “That is a very difficult thing to put your finger on in terms of actual cost savings, but it’s a lot.”
Volume Tracking and Billing
Newall explains that calculating volume and monthly payouts for subcontractors like Goodmans Contracting is also much easier with Business Center - HCE. This is important because not only is the M2PP Alliance paid by each cubic meter of dirt moved, the rate M2PP pays its subcontractors varies as well. For instance, cut versus haul rates per section of road vary, as do rates for volume of material placed in-ground compared to solid volumes extracted. Where dirt is placed for bulk backfill versus where dirt is received and placed for peat replacement can also impact the payout for subcontractors. As a result, all parties want to monitor and manage volumes carefully.
Today, using Business Center - HCE Newall produces 3D surface images and volume reports that very clearly shows how earthworks payouts are calculated. He believes this level of documentation improves communication between M2PP Alliance and subcontractors. It also adds accuracy and overall transparency to the billing and payment process, which is appreciated by all.
Several months into the project now, Newall explains that M2PP expressway is moving ahead quickly and is on track to meet its aggressive timeline. He also believes the Trimble Connected Site portfolio has been a game changer.
"When you look at the volume of information we collect, share and analyze on a daily basis, it just gives us a huge advantage in accuracy and productivity in everything from modeling and earthworks, to mass haul,” said Newall. “It’s hard to imagine we’d be able to produce these results so quickly without a unified view of the project and without the Connected Site from Trimble.”
For more information on M2PP www.m2pp.co.nz
Also watch the Connected Site and SPS Essentials Video
Trimble solutions used, include:
- Connected Office, Connected Community powered by Trimble
- Connected Machine (Trimble GCS900 Grade Control System)
- Trimble SNM940 Connected Site Gateway
- Connected Controller (Trimble SCS900 Site Controller Software)
- Trimble TSC3 controller
- Trimble SPS985 GNSS Smart Antenna
- Trimble SPS855 GNSS Modular Receiver