Experimental Study On The Strength Of TL-5 Concrete Bridge Barrier Reinforced With Stainless Steel Bars

AASHTO-LRFD Bridge Design Specifications provide equations for the flexural capacity of concrete barriers subjected to vehicle impact based on the yield-line theory. However, no experimental testing nor computer modelling was found in the literature to support the AASHTOLRFD triangular yield-line failure pattern. The objective of this study is to generate experimental research data on the behavior of Test-Level 5 (TL-5) concrete barrier reinforced with stainless steel bars when subjected to transverse vehicular loading. The experimental program included testing four actual-size barriers, two of 6.5 m length and two of 4.5 m length. One barrier in each group was cast over a thick undeformable concrete base, while the other barrier was cast over a short slab cantilever. The 6.5 m long barriers were tested under a transverse line load centered at their mid-length, while the 4.5 m long barriers were tested under transverse exterior line loading.

Results showed a trapezoidal flexural crack pattern in the barrier wall in contrast to the AASHTOLRFD triangular yield-line pattern. The 4.5 m long barrier supported on thick concrete slab and the two 6.5 m long barriers failed in a punching shear mode. While the 4.5 m long barrier supported on a cantilever failed due to flexural cracks in the barrier wall and the slab cantilever along with anchorage cracks at the bottom end of the diagonal bent bars in the barrier wall embedded in the deck slab. Finally, the experimental transverse capacity of the tested barriers was greater than the design value in the Canadian Highway Bridge Design Code. However, it is recommended to increase the embedment length of the diagonal bent bars at the barrier-deck junction to be 185 mm instead of 125 mm to assist in altering the observed flexural/anchorage failure mode to punching shear failure at greater applied loading.