Non-destructive testing helps finish design-build project a year early

Columbus, Ohio — Serving as the lead design consultant for a design-build team, Resource International, Inc. (Rii) used non-destructive testing (NDT) technology to accelerate the design and construction of a $54 million interstate widening and reconstruction project, which is now projected to finish a year earlier than originally scheduled. Rii credits construction acceleration to the use of innovative technologies and asset management capabilities in the planning and design process of the MRW-71-3.22 Interstate Reconstruction Project.

Rii's Heavy Falling Weight Deflectometer (FWD)/Ground Penetrating Radar (GPR) combination equipment.

Using the GPR/Heavy Falling Weight Deflectometer (HFWD), engineers in the field were able to determine structural information about the pavement in a short time throughout this project. This NDT technology provided an accurate estimate of layer thicknesses, pavement abnormalities, pockets of moisture accumulation, presence of voids, and material degradation. In addition, Rii’s JILS-20HF FWD, which is a high-force Heavy Weight Deflectometer, simulated the effect of a moving wheel load and provided an accurate estimate of layer moduli without destructive coring and sampling.

The Automated Dynamic Cone Penetrometer system provides accurate, fast and efficient test methods for pavement design projects.

Additionally, the Automatic Dynamic Cone Pentrometer (ADCP) system was used to provide non destructive, non intrusive information on subgrade soil strength. This was achieved in a matter of minutes instead of hours and days, which is often needed for conventional soil strength measurements.

The Rii Team uses technological capabilities such as these to give them expertise on design-build, public-private partnership, construction management, and transportation asset management projects. Without these technologies, a pavement failure would be more likely to occur on a project. A pavement failure at even the smallest size during construction would have a significant effect on maintenance of traffic operations and would cause delays, accidents and increased user cost to the public, design-build, or P3 teams.

The conventional solution for a pavement failure is to rebuild the shoulder diversion lanes to a sufficient strength. This comes at a substantial cost and loss of time for the client. However, this risk of failure can be unavoidable, depending on uncertainties associated with the condition of pavement and shoulder layers. Thickness variations, voids, abnormalities and localized failures may be unseen to the surface rating process. In addition, drainage, moisture conditions and sub grade soil strength variations require extensive investigation to document.

For the MRW-71-3.22 Interstate Reconstruction Project, the Rii Team proposed a design solution with 95-percent reliability, where the risk and probability of failure was minimized and Rejection Quality Levels (RQL) were set at less than 5 percent.

The conventional design recommendations for a no risk, high reliability design requires destructive testing, sampling and laboratory analysis at every 400 for each shoulder. This typically takes weeks of field and lab work at substantial cost to the project. In contrast, the Rii Team used non-destructive technology to perform the sub grade soil strength investigation at six to eight minutes each, saving time. Additionally, engineers mapped the pavement and shoulder abnormalities, voids, moisture and thickness. The pavement support stiffness values of all layers at 250 feet took less than two minutes each.

The innovative asset management technologies that were used on the MRW-71-3.22 Interstate Reconstruction Project have been developed, implemented and updated within the last 30 years by Rii. The Rii Team strives to use these technologies in all phases of projects including the development, scoping, maintenance of traffic, and construction phase.