Asset Assessment of Concrete Structure

Abstract

Infrastructures which were constructed in the last century are approaching or have exceeded their design life. It is essential to maintain, repair and rehabilitate existing structures to ensure safety and develop a sensible rehabilitation plan. This paper suggests an inspection program for the condition evaluation of existing structures, particularly for structures that are approaching or exceeding their design/campaign lives. Cracking on concrete bridges is often induced by static and cyclic temperature loading. Throughout the service life of the structure, cracks will initiate, propagate, coalesce and form a greater damaged zone. Depending on the location and severity of the crack network; corrosion of reinforcement, debonding between concrete and reinforcement, and spalling of concrete may occur. The implementation of regular inspection or monitoring of structural condition is an essential component of asset management. Early detection of damaged zones can ease scheduling and reduce the cost of repair, which in turn also allows extension of structural lifespan without compromising safety. Similarly, for industrial properties, asset management and rehabilitation programs are paramount as they can significantly reduce capital expenditures in asset maintenance, if implemented prior to or at the early onset of structural degradation. This paper illustrates the use of NDT techniques for the condition assessment of a prestressed concrete bridge, as well as concrete storage silos. Both of which were either approaching or have exceeded their design campaign life and were needing a proper rehabilitation plan. The assessment included crack movement monitoring, crack depth determination, concrete strength estimation, and the detection of debonding between rebar and concrete.