Recent changes in building code requirements and the TIA standard, compounded with ever increasing load requirements, have made it increasingly critical to obtain actual foundation data for tower structures. This includes not only the dimensions of the foundation element(s), but also the rebar content to ensure an accurate foundation analysis can be completed. Over time, foundation design drawings are either lost or the tower loading has changed and foundation recommendations are usually requested.
Until recently the only way to evaluate a foundation without any drawings was to excavate and expose the foundation to obtain dimensions and then chip out the concrete to obtain the rebar content. This type of effort involves disturbing load bearing soil and carries the risk of damaging the foundation and/or structure.
In addition, chipping of concrete to obtain rebar content compromises the integrity of the concrete and has the potential to damage rebar elements. Current technology allows for Non-Destructive Testing (NDT) methods to provide approximate dimensions and rebar content of existing foundations (in most circumstances), while minimizing the need for destructive methods.
EGSci Consulting has conducted over 2,000 foundation mapping investigations over the last 10 years across the United States on existing telecommunication towers (monopole, self-support, guyed), as well as billboards, water tanks, wood poles, embedded poles, and buildings to evaluate both foundation dimensions and rebar content. EGSci’s team of engineers and geophysicists employ an array of NDT methods using the latest equipment and software to provide the most accurate results.
Below is a list of methodologies that EGSci commonly employs for the mapping of existing foundations. The wide variety of methodologies at our disposal allows for EGSci to customize each foundation mapping investigation to meet the specific needs of the project. All services and equipment are in-house to maximize response and cost effectiveness.
• Ground Penetrating Radar (GPR)
• Sonic Echo / Impulse Response (SE/IR)
• Parallel Seismic
• Impact Echo (IE)
• Spectral Analysis of Surface Waves (SASW)
• Ultrasonic Pulse Velocity (UPV)
• Pulse Induction