Reliable non-destructive evaluation of heavily reinforced large concrete structures becomes more important every day as the US civil infrastructure continues to age. Use of low frequency ultrasound has shown some success, however, as the level of reinforcement and thickness increase, inspection issues remain. There is a need for tools to design, optimize and evaluate inspections to estimate detection capability as a function a wall thickness and level of reinforcement. A numerical testbed is being developed to meet this need. Using a 2D approximation simulation of inspection of concrete up to 1m thick and using frequencies of 50kHz can be assessed efficiently. Image processing techniques were used to mesh images of concrete microstructure and to generate a realistic local geometry for concrete samples. For initial code validation, the scattering response from a 3mm side drilled hole (SDH) in immersion was assessed. The code had good agreement with both analytical and experimental results. The code is being extended to consider various rebar geometries and aggregate combinations and initial data are reported. Material properties used were based on experimental measurements. The test bed is now being used to consider a sparse phased array, to optimize sensor placements, and evaluate inspection performance.