not that it’s more of an issue now; it’s just that it’s being discussed more. [Working platforms] have been an issue for a very long time.” In 2018, the ADSC-The International Association of Foundation Drilling (ADSC), DFI and Pile Driving Contractors Association (PDCA) came together and published a deep foundation industry consensus position on working platforms for foundation construction and related equipment in the U.S. In the document, the organizations outline that they will support the general guidelines used in the U.K., spearheaded in the early 2000s by the Federation of Piling Specialists (FPS), the piling association in the U.K. What Are Working Platforms? Essentially, the working platform is the part of the construction site above the natural subgrade on which a rig is placed and that holds the rig level to start its foundation construction activity. The working plat- form is what prevents these large pieces of machinery from tipping over and causing catastrophic damage. The scope of the consensus position statement from the ADSC, DFI and PDCA is focused on ground-supported working platforms and includes not only the platform itself, but also its associated ramps/roads and access points. Anywhere that a rig is tramming/ driving or working from must be able to support safely the weight of the equipment and any bearing pressures during con- struction activity. An example of a well-constructed and maintained working platform “The platform must safely support any type of tracked equipment — whether it be a crawler crane, a piling rig or whatever it may be — under all loading conditions,” noted Gildea. “And the way we look at this is under extreme loading conditions; we’re looking at the worst case here because the platform needs to be fully stable under all potential loading conditions for these rigs so that there is no possibility that it can collapse and the rig topple over.” The Concerns In 2017, DFI conducted a survey of its membership about experiences with working platforms. The results highlighted the significance of the problem: 88% of respondents to the survey indicated that inadequate working surfaces caused safety issues for their company, and 98% specified that the working surfaces caused opera- tional issues for their company. Even more alarmingly, 68% admitted that their com- pany had tipped a large piece of equipment due to inadequate working surfaces. “These results weren’t surprising,” commented Taube, who along with Matthew Meyer, P.E., principal at Langan Engineering and Environmental Services, assisted DFI in creating the survey questions and presented the results during DFI’s SuperPile ’17 Conference. “You can see that it’s a huge issue.” Inadequate working platforms have myriad issues that result in safety concerns. “The most common hazard is soft soil that is too weak to support the construction equipment,” added Timothy Siegel, P.E., G.E., D.GE, senior principal engineer with Dan Brown and Associates. In addition to soft soil, steep slopes can result in failure, as can inadequately con- structed ramps, or platforms that do not have enough coverage over a site. Uneven terrain, ineffectively backfilled utility trenches and poor site drainage can also be causes for concern. The size of the working platform can be a potential problem, too. “Sometimes, the working surface isn’t large enough,” declared Taube. “You might not have a working platform in the laydown area or access roads to the site. And then, within the site, the working platform may be laid out only to encompass the installation point locations, not considering that some of the equipment may need to traverse out beyond the actual perimeter of the installation area.” And, in some cases, there is no working platform to speak of. “Another issue is that a platform isn’t provided at all,” added Taube. “Either contractually it’s not required, or it’s an oversight. There are still contractors that will go out and work without a working platform.” Examples of tipped over drill rigs due to unstable working platforms 96 • DEEP FOUNDATIONS • SEPT/OCT 2019
