Overlapping free-standing portable concrete barriers (PCBs) are commonly used in work zones. Despite widespread implementation, overlapping configurations have not been evaluated through full-scale crash testing under the Manual for Assessing Safety Hardware (MASH) (1). As a result, transportation agencies rely largely on engineering judgment when deploying overlapping PCBs.

This study evaluated the safety performance of overlapping free-standing F-shape PCBs under MASH Test Level 3 (TL-3) conditions through a combination of survey research, finite element (FE) simulations, and full-scale crash testing. A survey of Roadside Safety Pooled Fund members identified common barrier profiles, connections, and overlap configurations. FE models were developed and validated against prior MASH TL-3 crash tests involving free-standing F-shape barriers (2). The validated models were then used for parametric simulations to evaluate the effects of overlap length, gap size, and impact location, leading to identification of the recommended configuration.

The configuration with 1.5-barrier-segment-length overlap and no gap between parallel barrier runs was selected for full-scale crash testing. MASH tests 3-10 and 3-11 were conducted and met the evaluation criteria. The results establish a practical, crash-tested configuration for overlapping free-standing F-shape PCBs and support safer work zone barrier installations.