Introduction
The need for innovative construction techniques and sustainable construction materials have completely reshaped the construction industry. Following the need for high-performance and environmentally-protected construction materials, FRP composites have gained gradual but wide acceptance from civil engineers around the world. Properties like high tensile strength, ease of installation, low maintenance cost, and resistance against harsh environmental conditions give FRP composites a clear advantage over traditional construction materials. The application of fiber reinforced polymer in civil construction ranges from rehabilitation of existing reinforced concrete (RC) to building new projects. This blog post will talk about the application of FRP composites in bridge infrastructure.
What are FRP composites?
Fiber and matrix are two major ingredients that are used to develop FRP construction materials. The properties of these modern construction materials are largely determined by the quality and ratio of its constituents and manufacturing process. The function of fiber is to provide stiffness and strength while matrix is responsible for providing FRP composites with environmental protection and rigidity.
The application of FRP composites in bridge structures
As a result of extensive research investigating the applicability of FRP composites in the bridge construction, advanced composite materials, especially GFRP rebar, is now being increasingly used to construct the new bridges and strengthen the existing structurally deficient bridge structures in North America. Why should traditional materials be replaced with FRP composites?
Concrete provides a solid cover for steel reinforcement, however, despite the cover, severe environmental conditions can cause the formation of hydrated ferrous oxide that can lead to the deterioration of concrete members. FRP composites provide complete protection against the environment and concrete degradation and this is exactly why the focus of civil engineers have shifted from steel to fiberglass bars over the past few years. It is in the interest of a country to build bridges that can offer an exceptionally long service life with very low maintenance cost.
Since FRP composites are corrosion resistance, they can be used to replace steel reinforcement in the forms of rebar for shear and flexural reinforcements, and tendon for pre-stressing or post-tensioning. FRP rebar and tendon can be manufactured in multidimensional or one-dimensional forms depending on the nature of application.
Rehabilitation of existing bridge structures
Fiber reinforced polymers was first introduced to civil engineering as a replacement of steel materials to strengthen and retrofit existing bridge structures using externally bonded FRP composites. In the strengthening and retrofitting application of FRP composites, sheets and strips are employed to increase the efficiency and strength of an underperforming or deteriorated bridge. These techniques have been used for improving both shear and flexural capacity of concrete members.
So far as seismic retrofitting of reinforced concrete is concerned, FRP composites can be used in the form of wrapped column. Traffic disruption is the biggest hurdle that engineers face while carrying out seismic retrofitting of bridges. One of the advantages of fiberglass rehabilitation material is that they are easy and quick to install without disrupting the flow of traffic.
The use of these corrosion-free and modern construction materials can save governments billion of dollars annually and can help build a sustainable bridge infrastructure.
