Whether a tile system, earthworks, paving project or landfill, there are three common threads in planning a successful project:
1. A high accuracy topographic map of the project area is critical. Depending on the scope of the project the designer can use photogrammetry, GPS mobile mapping, LIDAR, or standard data collection methods. Background imaging and existing data can also be incorporated for more detail.
To ensure the data is accurate and repeatable, a good survey control network should be the basis for the following data layers. Depending on the area or complexity of the project, the density, accessibility, and accuracy of the network has to be thought through and implemented accordingly.
Where large areas are involved, the surface data collected has two major components: accuracy and density. Make sure that both of these are addressed in the final product.
2. There are many planning and design tools available. Many of these are built for specific types of work, ranging from simple site work to detailed construction plans. Planning a project can be a very time consuming and costly part of the end result.
A design program should fully address the scope of the work, but recognize that many projects succeed based on the practical application of knowledge gathered by people without the time or proclivity to run high level engineering software. It is imperative to understand what will be expected by the customer and his budget, then choose the right program to fulfill these expectations.
3. Once the data is collected and the design is in place, the layout and machine control functions are ready to be implemented for a final product. Choosing the right methods and instrumentation is critical. A contractor must understand the abilities and limitations of the different types of machine control available. Lasers, RTK GPS and Robotic Total Stations (RTS) are generally considered to be the three modern options for machine control.
Lasers and RTS are both optical instrumentation. They are affected by atmospheric conditions like dust, precipitation and heat. They are are ground-based and need a clear line of sight to the machine-based target. Distance from the transmitting instrument to the target is critical and can force moving and resetting the instruments. Linear projects can dictate a setup crew with multiple instruments to keep a fast paced project on schedule.
GPS is satellite-based and has other issues to conquer. Space weather, storm fronts, multi path and clear view to the sky are all important. Setting up the RTK base station properly is essential. Knowledge of GPS signals and their idiosyncrasies is fundamental to a successful machine control system. Used properly, its accuracy and ease-of-use can keep a project on grade and on time, every time.
At the end of the day, it takes the right people, using equipment in good working order, with proper machine control technology to complete a successful project. Are you bringing those to your job sites?