Employing Knitted-Fabric Composites for Bridge Construction




About the Project


The “Bridge in a Backpack” system, developed at the University of Maine’s Advanced Structures and Composites Center (ASCC), is currently constructed using Concrete Filled Fiber-reinforced polymer (FRP) Tubes (CFFTs) made with braided fabrics.  This project aims to investigate the potential for using a knitted reinforcing fabric in the CFFTs. It is unknown what the outcome of using knitted fabrics will be, but possible benefits include changes to the strength of CFFTs, stiffness of CFFTs, ability to manufacture FRP sleeves with non-constant cross sections, and the ability to manufacture FRP sleeves having a shape that is similar to the desired final shape, thus reducing residual stresses due to shaping of the FRP sleeves.

This project proposes to investigate the potential of knitted reinforcing fabrics by manufacturing and characterizing properties of four 1/5th-scale CFFTs employing two types of fabrics: braided and knitted.  Specifically, it is proposed that a non-concrete-filled CFFT of each type will be loaded in four-point bending, and a concrete-filled CFFT of each type will be loaded in four-point bending.  Additional tests may include coupon testing of each type of fabric in dry and resin-infused conditions.  The estimated completion date is May 2016.









Additional Content

Knitted CFFTs is an expanded research of the braided CFFTs used in the bridge-in-a-backpack. The bridge-in-a-backpack technology has been used in 18 bridges and beyond in the United States. The system has decreased construction time, is corrosion resistance, and lasts roughly 2 or 3 times longer than a standard bridge. The goal in investigating knitting technology is to understand the behavior of the composite when loaded, and to hopefully even further decrease construction time by being able to knit an arch nearly the shape needed for the project. To learn more about the current bridge-in-a-back technology please visit the Advance Structures and Composite Centers website. ASCC






Team Bios



Carlton Allen






My name is Carlton Allen. I grew up on a farm in central Maine. Sometimes you need to get creative doing repairs. I always wondered how some of the… peculiar DIY projects held together. Those are just a few of the many things that got me interested in Mechanical Engineering Technology. I am always searching for how stuff works and why.

I have started my career in the HVAC industry with an internship this past summer and I am continuing to work over the school year.


Niall Craig







Niall Craig is a senior at the University of Maine with a major in Mechanical Engineering Technology and a minor in Renewable Energy Science and Technology.  Niall was born in Dundee, Scotland but moved to Walpole, Massachusetts and was raised there.  After graduation Niall would like to begin a career in the Renewable Energy Engineering field.


Tim Heno






Tim Heno is majoring in Mechanical Engineering Technology (MET) while minoring in Electrical Engineering Technology (EET) at the University of Maine. He is from Franklin, Massachusetts and has chosen the University of Maine because of how hands-on and practical designing the MET programs is. Tim plans on achieving his masters in Mechanical Engineering with a focus of study on mechanical systems for commercial buildings while working full time after graduation.


James Martin






James Martin is a senior in Mechanical Engineering Technology at the University of Maine. James has previous engineering experience including a Project Engineering Internship at a pulp mill and an undergrad research experience in automotive engineering at Virginia Tech. After graduation James would like to start a career in Engineering or Project Management.





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