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Design and Implementation of the Manitoba Constrained-Width Tall Wall Barrier


Manitoba Infrastructure (MI) desired a new, tall concrete median barrier capable of satisfying the
Test Level 5 (TL-5) safety requirements of the Manual for Assessing Safety Hardware (MASH).
It needed to fit within the footprint of an existing F-shape median barrier located in a narrow
median. It also was required to address headlight glare from opposing traffic. The barrier was
designed with a height of 1,250 mm, a maximum width of 600 mm and to resist a load of 845 kN
applied at the top of the barrier. The Manitoba Constrained-Width, Tall Wall was optimised to
withstand the design load while minimising the amount of steel reinforcement. Variations of the
barrier were developed, including a bridge rail and a roadside barrier.
The bridge rail was considered to be the critical design due to its narrow width and anchorage to
a relatively thin, cantilevered bridge deck. Thus, one full-scale vehicle crash test was conducted
on the bridge rail system to verify the entire family of barriers. A vertical back barrier (45.72 m
long) was constructed. It had a height of 1,250 mm and widths of 450 mm at its base and 250
millimetres at the top. The upstream half of the barrier (22.86 m) was constructed on a
simulated bridge deck that was 280 mm thick. A gap in the bridge rail was constructed that was
168 mm wide and a gap in the bridge deck that was 19 mm wide; these were placed mid-span
to simulate an expansion joint. A steel cover plate was placed over the barrier joint to prevent
vehicle snag. During the test, the tractor trailer impacted just upstream from the joint and was
safely redirected. The barrier sustained minor damage in the form of cracks and spalling.
Anchorage options were developed for use with the TL-5 barrier system, including a foundation
slab and an independent footing. Transition systems were also detailed for the connection of
the TL-5 median barrier to various other new and existing barrier shapes. Finally, Manitoba
Infrastructure developed a full series of barrier systems for median and roadside conditions that
will provide designers many options to create construction drawings for their projects that are
specific for their site(s).

Conference Paper Details

Session title:
Innovations in Road Safety
Larsen, H.
Rosenbaugh, S.
Pankratz, A.
Emerson, D.
Schmidt, J.
Faller, R.
Regier, E.
Road safety