An elongated structural barrier is provided including a base, a first panel extending upward from the base, a first sealer wall extending downward and transversely to the base, a second panel joined with the first panel and extending upwardly, a lower wedge extending upward from the base adjacent the first sealer wall, and a core compartment bounded by the lower wedge and the panels, with an open face defined above the lower wedge and offering a view into the core compartment. The lower wedge can include a flange to produce a first cavity of the compartment, in which an intumescent core can be positioned and configured to expand into a second cavity of the compartment when it swells. A second flange can oppose the first flange to further secure the core in the first cavity, and can form a bloom gap therebetween. A related method of use also is provided.