Beyond Crashworthiness A Critical Review of Structural Demand Damage Mechanisms and MASH Compliance in Permanent Concrete Median Barriers

Permanent concrete median barriers are generally considered rigid roadside safety systems; however, their behavior depends on the interplay between barrier geometry, barrier height, reinforcing, anchorage systems, supporting structure, vehicle attributes, and impact conditions. With the introduction of the MASH, the difficulty level of the single-unit-truck Test Level 4 impact increased, and shortcomings of using only historical crash test acceptance criteria became evident. This literature review focuses on permanent concrete barrier geometries, MASH evaluation criteria, observed displacements and damages, impact forces and structural demands, and full-scale crash tests versus finite element nonlinear analyses. Data from crash-test reports, experimental studies, and LS-DYNA analysis reveal that the containment and stability of vehicles cannot be determined solely based on the nominal strength of the barrier. While geometry and height influence vehicle climbing and rollover tendencies, reinforcing, deck/foundation continuity, and load transfer define cracking, punching shear, and plastic deformation. While full-scale testing provides a basis for safety evaluation, validated nonlinear simulations allow analyzing force history, failure modes, and variants that cannot be tested once. In view of the current literature, the approach to evaluating the behavior of permanent concrete median barriers should encompass a combined consideration of MASH crashworthiness criteria, structural capability, and validated simulations. The remaining challenges relate to the proper definition and reporting of barrier deformations and damages, more advanced dynamic force definitions, validation of concrete failure models, and performance-based criteria for extrapolation of test results to similar barriers.