Polyester strap reinforcement, Maccaferri

Polymer Strip Reinforced MSE Wall, TRB
Polymeric strip reinforcement, I95 Delaware
The annual Transportation Research Board (TRB) meetings in Washington, D.C. provide some of the most influential transportation engineering discussions. Geosynthetics are always part of papers, standards discussions, research awards, and more at this 12,000+ attendee event that draws experts from around the world. Now, it has been announced that the TRB 2015 paper “Instrumented MSE Wall Reinforced with Polyester Straps” (Paper #15-0985) has been named Best Paper 2015 by the Soil Mechanics Section.
The paper, which was sponsored by TRB committee AFS10 Transportation Earthworks, was co-authored by Yushan Luo, Dov Leshchinsky, Pietro Rimoldi, Giulia Lugli, and Chao Xu.
Mechanically stabilized earth (MSE) walls are using more polyester strap reinforcement with large concrete panel facing. The paper, using AASHTO methodology, shows how instrumentation has been used to establish extensibility in a reinforced wall system. The system is, in fact, part of a new interchange on Interstate 95 in Christiana, Delaware.
In the abstract, they write:
Monitoring included tensile force distribution at selected straps and force at the connection of a few straps to the large concrete panels. The recorded data is from April, 2012, the beginning of construction of the instrumented wall, to June 2014, about 20 months after the end of its construction. When classifying this reinforced wall system as “extensible”, the maximum load in the straps and connections are about 4 times smaller than predicted using AASHTO and the lengths of the reinforcing straps are adequate enabling it to mobilize the required loads. The indicated conservatism of the measured versus predicted maximum load in the reinforcements is attributed to significant underestimation of the reinforced soil strength in AASHTO’s design and, potentially, to a large toe resistance. The data suggests that AASHTO’s design based on extensible reinforcement for this family of MSE walls is adequate.
The chair of the Soil Mechanics Section will present the award to the authors during the TRB 2016 Annual Meeting (January 2016) at the Transportation Earthworks Committee.
The paper is available from TRB.
The 95th Transportation Research Board Annual Meeting (TRB 2016) will be held 10–14 January 2016 at the Walter E. Washington Convention Center in Washington, D.C.