Trimble Site Supervisor system puts design information at the fingertips of supervisors

The SafeLink Alliance project is an $AU700 million highway construction job located in Brisbane, Australia. It involves upgrading 8km of two multi-lane motorways; a new multi-level interchange system; a new rail formation through the interchange that will join at either end to an expanding public transport system; over 5km of new service roads; 27 bridge structures; as well as a new outdoor sporting complex and numerous pedestrian and cycle paths. The work involves moving approx 1.2 million cubic meters of bulk earthworks and over 420 thousand tonnes of asphalt.

The project makes up a significant section of the Qld Government’s $AU16.2 billion dollar investment in road construction and upgrade projects over the next 5 years. With south-east Queensland currently experiencing a significant economic boom period and rapid population growth, much of this funding has been invested in large scale projects designed to open up already congested traffic routes in order to promote new residential communities throughout the region.

The sheer number of large-scale construction projects in south-east Queensland’s relatively small geographical area has resulted in a skills shortage in all segments of the construction industry. This includes the availability of surveyors and qualified field supervisors – especially those with the ability to read and interpret design drawings. This skill shortage coupled with SafeLink’s vision of best practice and commitment to safety has resulted in a re-think of the traditional construction methods.

The SafeLink Alliance employs the use of Trimble machine control across all work areas. The project utilizes 20 GPS-guided machines including excavators, pad-foot compactors, bulldozers, smooth-drum vibrating rollers – as well as 7 graders that are able to switch between GPS and UTS guidance.

SafeLink still have quite a number of traditional survey crews on-site. The project operates with 8 field crews along with 3 surveyors that split their time between office and field and 2 full-time office surveyors.

Some of these crews are dedicated completely to bridge and wall structures (for which no machine control is used). Their involvement with the earthworks side of the job is largely limited to topographical pick-ups and Quality Assurance checks along with the set-out of objects that occur after the machine control has left – e.g. kerb and channel, concrete barriers, road furniture, line-marking, etc.

Thus, with the widespread use of machine control replacing traditional survey methods in bulk earthwork operations, SafeLink Alliance have gone a long way to creating a pegless site. The site relies heavily on the use of 3D guidance methods rather than the rows of batter boards and survey stakes that line traditional work areas.

The Challenge of a Pegless Site

The move to a pegless site presented SafeLink with its first and biggest problem. While a pegless site has certainly helped streamline the survey operations of the project, it did pose a significant challenge to the supervisors responsible for overseeing on-site operations. With no survey marks available to them, the field supervisors were effectively working in the dark – struggling to visualise what they were trying to build. In fact, instead of the supervisors, the actual machine operators now had all the design information at their fingertips.

Therefore if the Alliance was going to try and keep the site pegless, it was necessary to find a solution that allowed the field supervisors’ access to the same design information as the machine operators. This is where the Trimble® Site Supervisor system really came into its own.

As part of their day-to-day job, the field supervisors are constantly driving up and down the job-site. By installing the Trimble Site Supervisor system into their site car with the screen display mounted on the vehicles windscreen, supervisors now have access to both basic cut/fill levels as well as long-section and cross-section information – displayed right in front of the operator and covering every millimeter of the roadworks.  With just some basic system training, supervisors are now empowered with the information they required to both visualise the job and check on the progress of the equipment under their supervision.

SafeLink originally tested the Site Supervisor kits by having one system available to the whole job on an as-required basis. However, it was such a popular item that, within weeks each work area had their own dedicated Site Supervisor kit assigned to a vehicle in that area. The individual vehicles are generally driven by the Leading Hand who is the main field contact and always on site, but the Foreman or Engineers are able to use the vehicles as required. The supervisor vehicles are also equipped with roof-mounted flags so that if anyone on the ground requires a level, they can simply waive down one of these flagged vehicles for an instant update.

The same problems of a pegless site also apply to Client Inspectors. These State Government representatives are often required to come on site and inspect various aspects of the works. This is a difficult task when there are no pegs to reference and very little design information available. To combat this, the Alliance decided to purchase extra Trimble Site Supervisor kits and fit these to the Client Inspector vehicles. Now, in the same way as the Supervisors and Engineers do, the client representatives can drive anywhere throughout the site and gain realtime information on the progress of the works.

As well as this, Client Inspectors – who often inspect multiple sites around the local area – are able to obtain design information from any other Trimble-equipped project in the same manner. This empowers the client to inspect on-site operations at any stage with minimal disruption to field crews.

The SafeLink site currently utilises 7 Trimble Site Supervisor systems – split between field supervisor crews, engineers and client inspectors. On top of this, many of the field survey crews have special brackets that allow them to mount their SPS881 Rovers to the outside of their vehicles and effectively create their own Site Supervisor system when required. 

Changing Designs

The second challenge encountered on the SafeLink project was related to the design itself. As both the client and the designers are part of the Alliance venture, the roadwork design is continually being refined and updated as the project progresses. The consequence of this is that any design drawings that were available to the field were continuously being superseded and there was real risk of an intended design change being missed in the field.

This was also true of any survey marks that had been set-out in the field. When a design was changed the pegs became inaccurate until the survey crews were available to re-mark (or completely remove) them. Indeed, you would need an army of surveyors available if they were required to update all changes in designs instantaneous.

However, by using the Trimble Site Supervisor system in replacement of survey pegs, the design changes are electronically updated into the system in the same manner as survey crews ’ controllers – making any design change almost instantaneous. The operator merely needs to bring the SCS900 Tablet back into the office to synchronize with the designs folder – or if necessary, the new design can be uploaded in the field via USB transfer.

Confined Working Spaces

The third obstacle encountered at SafeLink is the difficulty of access within confined spaces around the jobsite. Much of the works are alongside existing motorway and one of the pre-requisites of the project is that the traffic reliability and existing traffic routes are to be maintained during construction. Because the cut and the fill operations are often separated by live motorways, earth is moved using truck and dogs. This results in continuous rounds of road trucks coupled with heavy earthworks machinery – all working in confined spaces that are difficult to access.

There is an obvious safety concern with surveyors or supervisors walking around in such conditions. The project is very conscious of safety matters – as is evident in the "SafeLink" name – and maintaining a safe working environment is the top priority of the Alliance.

This confined environment also makes any peg set-out difficult to maintain. With so much construction activity and heavy vehicle movements, any pegs that are on the ground are destined to lay on their side sooner rather than later.

But with the Trimble Site Supervisor system mounted on top of site vehicles, the operator is able to quickly and easily acquire real-time information and provide that to others in the field, all without leaving the relative safety of their vehicle. This is undoubtedly safer than surveyors needing to be on the ground trying to sledgehammer pegs whilst dodging trucks – and is also safer than foreman and general earthworks crews having to be on the ground to read and utilise the pegs. 

Thus the Trimble Site Supervisor system has helped solve a number of potential on-site problems. It has helped facilitate the use of a pegless site by empowering field supervisors, engineers and client representatives with the required design information previously held exclusively by survey crews and/or machine control operators. The system has also ensured that the latest designs can be instantaneously updated in the field and has helped the safety aspect of the job by reducing the need for on-the-ground set-out and stringlining. 

Extra Benefits

In addition to solving these challenges, there have been more than a few added benefits that have been gained from using the Site Supervisor systems – mainly arising out of the fact that field supervisors have instant access to valuable information that can help in both planned and unplanned works.

Forward Planning

The first of these benefits is that everyone – surveyors, supervisors and machine-guidance operators – are all working with the same information. Thus, everyone has a similar knowledge of the job.  Because everyone has a similar knowledge of the job, all the information is readily available for supervisors to be able to forward plan their works. No longer does the Leading Hand or Foreman need to spend time liaising with Designers and Surveyors and waiting for the required information. They can now quickly and easily access information for the entire job and plan their forward works accordingly.

Unplanned Works

Another benefit that has arisen from utilising the Trimble Site Supervisor systems is the ability for field crews to work without the need to wait for surveyors. Especially useful for unplanned works, the supervisor now has the ability to commence basic works prior to survey set-out or without machine-control. This includes the ability to start topsoil strips and cut/fill operations.

It has also helped with on-site planning of basic infrastructure such as haul road positions, site compound locations and temporary drainage requirements. These tasks can be commenced – if not completely accomplished – using the Site Supervisor system without the need for booking survey crews or GPS machinery.

Less Reliance on Survey

The Trimble Site Supervisor kits have allowed supervisors to take responsibility of basic – yet time-intensive – survey tasks. Using the Site Supervisor kits, Leading Hands can easily record significant locations such as soil tests. They can also perform other relatively simple survey tasks whilst on-site like picking-up bulk earthwork levels. This also allows more efficient use of valuable survey crew time. 

Similar to this, the supervisor is able to easily perform basic volume calculations in the field. Even if they are not comfortable with the Cogo functions, the supervisor can easily determine basic surface area and cut/fill measurements. This can be used for simple calcs in order to help determine whether more material is required and assist more efficient on-site plant management. 

A further unexpected advantage of using the Trimble Site Supervisor system is that we have effectively developed a whole breed of quasi field surveyors. At times when basic survey tasks are required but no surveyor is available, a supervisor that is familiar with the system is able to borrow a traditional survey rover and operate it with a fair amount of confidence. The SafeLink project has even had Leading Hands and Engineers working on night shift with the ability to perform basic survey pick-ups and set-outs – rather than needing a surveyor to sacrifice a day shift for what is a relatively simple task at night. 

Site Supervisor in the Office

When back in the office, the supervisors can also take advantage of the Site Supervisor PC Simulator. The Simulator is easily installed onto any computer and the supervisor simply uses their current knowledge of the system to run it – effectively "walking the job" in the office. Earthworks supervisors can even be found firing up the PC Simulator rather than reaching for design drawings when trying to visualise the project or explain something to engineers or subcontract suppliers. 

Closer Relationships

Another somewhat unexpected benefit of giving field supervisors access to traditional survey information is the closer working relationship that has developed between the two groups. Traditionally in the Australian construction environment, surveyors do not get involved with any earthworks planning – they are largely removed from the earthworks operation and responsible purely for setting out the intended design and then checking completed works against the design. SafeLink surveyors have found that they are now working closer with the field crews, which has helped open up communications between them and helped both crews develop a better understanding of the others position.

Cost Benefits

It is certain that the Trimble Site Supervisor kits have produced some project savings – although putting real figures on this is somewhat difficult. If required to peg the job in order to provide a reference for field supervisors, a conservative estimate would require the employment of at least one extra survey crew for each of the 4 major work areas.

Comparing the cost of the Trimble Site Supervisor systems purely against what would be required in the extra survey crew wages and required equipment over the 3 year length of the project, the estimated project saving is in the $AU4 million dollar range. This doesn’t include the cost of the survey stakes that would be required, nor the cost of hardcopy drawings that the supervisors would need to carry with them for reference.

It should be noted that the Alliance has also invested over $AU2 million dollars in machine control guidance. This investment has not come into the above equation because the machine guidance was already being used on-site. The cost savings are merely a comparison of employing surveyors to peg the job for the sole purpose of being used as a reference by supervisors (which was what was being requested at one stage of the project) versus the use of the Trimble Site Supervisor system as a referencing system.

All this being said, the biggest cost saving to the project would have to be the increased job satisfaction – which in turn results in less staff turnover. Because of all the benefits mentioned above, the field supervisor has become more involved with the project and is taking more pride and ownership of their section of the job. Engineers and office staff are realising that the field supervisors are fast becoming very valuable employees and are putting greater trust in their Leading Hands to get things right. Similarly, as the survey crews are performing less of the manual and repetitive task of pegging, they too are able to move on to more satisfying tasks, increasing their job satisfaction.

Conclusion

The Trimble Site Supervisor system has become an integral part of our works on the SafeLink Alliance project. The system works perfectly in conjunction with machine-control guidance as a way of empowering users with information previously held exclusively by survey crews and machine operators.

The Site Supervisor system can also provided solutions to many other construction challengers. This instant electronic update of designs helps to ensure that all amendments are quickly and easily transferred to the field. The very nature of the system being installed into a vehicle and all design information being available without needing to step out of a site vehicle can have enormous OH&S benefits also.  But more than this, the Trimble Site Supervisor system also allows users access to information that can assist in planning future works and helps field crews react to unplanned works without the need to wait for surveyors or machine-guidance. It also reduces the reliance on traditional survey crews, allowing on-site users to assume responsibility of basic survey tasks and facilitates simple field calcs in order to more efficiently control resources such as plant and material ordering. Sharing the survey tasks between crews also helps with team bonding and individual job satisfaction as well as creating individuals that become more valuable to the project as a whole. Additionally, there is a very real cost saving for the project with the use of the Trimble Site Supervisor systems.