Subsurface Drainage Systems in Roadway Construction

The installation of subsurface drainage systems has been a common practice in roadway construction for many years. Until recently, however, the ability to inspect and report on the condition of these systems once they are in place has been limited. The use of a high-tech, closed-circuit video monitoring system for the inspection of subsurface drainage systems has been developed and utilized with a high degree of success. The use of this system is beneficial for maintenance and rehabilitation of existing systems and as a quality control measure for new highway systems. In an ongoing project for FHWA, video monitoring has identified crushed mainline drainage pipes in new systems that have yet to be open to traffic. All of the components of this monitoring system can be easily operated by one person in the field. Substantial cost savings can be realized by accurately identifying the specific areas that need repair rather than assuming that an entire system needs to be replaced in highway rehabilitation projects. Results from use of this new technology to date are presented here.