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Most of the bridges in the North America were built before the earthquake design procedures were developed and implemented. The contemporary seismic design practices of RC structures encourage the use of adequate means to prevent premature failure of members subject to inelastic cyclic loading. Recent earthquakes have repeatedly highlighted the vulnerabilities of the corroded and old RC bridges to seismic deformation demands.

The term seismic retrofitting refers to structural upgradation designed to enhance the resistance of an existing concrete member to seismic loads. The analysis and evaluation of a structure highlights the shortcomings which prevent the structure from performing and fulfilling established seismic standards. The rehabilitation process is then designed to upgrade a structure in terms of seismic response.

When bridges are evaluated, it is defined whether or not the bridge is functional and does its intended job. If a bridge structure cannot handle weight, traffic volume and speed or lacks in terms of safety, it is considered as structurally deficient. The implementation of corrosion control systems and seismic rehabilitation can extend the service life of a bridge.

The use of fiber reinforced polymer (FRP) is becoming increasingly common in the development of new concrete structures. However, reinforcement corrosion and structurally deficient structures represent one of the longstanding structural challenges. The composite materials (FRP) are high-performance materials that can be used for seismic rehabilitation of reinforced concrete bridge columns. The favorable properties of composite materials and appropriate seismic strengthening practices can enable a bridge to withstand heavy earthquakes. This is why seismic rehabilitation of old bridges is largely performed using FRP materials.

Related: The Application of FRP Composites in Bridge Structures

Why FRP composites for seismic rehabilitation?

Seismic vulnerabilities of bridge structures constructed prior to 1970 have become evident following the major earthquakes. This put extra strain on the construction industry to upgrade deficient bridges which comprise a major portion of civil infrastructure in North America. Following are some of the factors that justify the use of FRP composite in bridge rehabilitation applications:

• High strength-to-weight ratio
• High stiffness-to-weight ratio
• The ease of production, handling, and installation of FRP wraps
• Minimal disruption to traffic
• Corrosion resistance of FRP protects the inner reinforcement against further corrosion
• FRPs do not reduce the clear height of a bridge
• Reduced maintenance cost
• The properties of FRP can be tailored for unique applications

The concrete infrastructure has been adversely affected by corrosion and weathering over the past three decades. Highway concrete bridges, in particular, experience premature structural decay as a result of heavy seismic activities and steel reinforcement corrosion. Because of enormous rehabilitation cost, FRP materials are being increasingly used in new bridge applications.

About Tuf-Bar

Tuf-Bar is an innovative producer and seller of GFRP fiberglass rebar in North America where we design and manufacture sustainable construction materials that can be used for both new and rehabilitation applications. Our products include fiberglass rebar, concrete anchors, rock bolts, and form ties. Visit our site to explore how advanced composites can help you build durable RC structures.

Rapid degradation and corrosion of steel reinforcement has been a major concern in North America. Following the infrastructure crisis, the use of fiber reinforced polymer (FRP) and its variants as an alternative to steel has gained popularity due to the ability of FRP composites to fight corrosion. Concrete structures such as bridges and seawalls are subjected to aggressive environmental conditions where it is hard to stop corrosion process using old-fashioned techniques. Concrete bridges also have to resist the impact and dynamic loads.

Researchers have conducted a number of experimental investigation programs to study the behavior of beam-columns joints reinforced with GFRP fiberglass rebar and strips. The major purpose of those studies was to investigate the performance of GFRP reinforcement and compare it to that of steel reinforcement.

There is a broad range of possible applications of unidirectional FRP grid-reinforced structures. The applications include barrier walls, water tanks, curtain walls, tunnel lining, and bridge decks. FRP grids offer a number of advantages ranging from fatigue resistance to high durability. FRP composites are lightweight and can be manufactured in accordance with the requirements of a project. Reduction in assembly work at sites can reduce the cost of a project. FRP grids is an excellent reinforcement solution for offshore or coastal concrete structures.

Corrosion of traditional reinforcement is considered the primary cause of deterioration of concrete infrastructure. We know how expensive it is to repair or rehabilitate the structurally deficient structures. According to an estimate, more than 40% of the global production of steel is used to fix corrosion related issues.

Electromagnetic neutrality is another reason why FRP composites are gaining attention from the civil engineering community. Sensitive structures such as hospitals, military facilities, and scientific research centers require a nonmagnetic environment with no metallic reinforcement. GFRP rebar is a non-metallic product that offers electromagnetic neutrality. This has led to the increasing use of GFRP reinforcement in waterside and other critical applications. Moreover, GFRP reinforcement makes it easy to embed fiber optic strain measurement devices. Measurement devices or sensors are critical so far as monitoring process is concerned.

Composite materials will play an important role in building sustainable concrete infrastructure. Unique and favorable characteristics make GFRP rebar suitable for applications where steel cannot meet sustainability requirements.

Detailed experimental studies conclude that GFRP-reinforced concrete structures have been performing extremely well under aggressive environmental conditions. It’s high time to explore the true potential of these innovative and promising construction materials.

At Tuf-Bar, we have been striving to design and manufacture high-quality, corrosion-free construction products for many years. Being a leading producer and seller of GFRP fiberglass rebar in Canada, our prime focus is to build and strengthen the concrete infrastructure through durable, maintenance-free solutions. Reach us to know more about our GFRP products!

Concrete is an incredible building material which engineers have been using for centuries to build all kinds of structures. The civil engineers started using reinforced concrete in the 1800s. Since that time, the construction industry has taken full advantage of reinforced concrete and its properties. Wastewater tanks and other water management facilities are largely built with reinforced concrete.

Unfortunately, the use of steel as concrete reinforcement gave birth to a new problem called corrosion. The corrosion of reinforcement can seriously affect the durability and service life of a structure. When the steel reinforcement corrodes, it can lead to cracking and spalling. The concrete spalling and cracking not only allow deleterious elements to penetrate through concrete but also damage the structural integrity.

Water treatment facilities are sensitive structures subject to the harsh environment. Freeze-thaw, abrasion, and chemical attacks are some of the reasons why waterside structures corrode. The ideal technique is to reinforce water tanks with corrosion-free materials such as fiber reinforced polymer (FRP). There are thousands of water tanks built with traditional materials in the 70s. As these tanks enter their fourth and fifth decade of service, the deterioration of the reinforced steel starts to become apparent. The damaged layer of concrete accelerates the deterioration process as corrosive elements easily find a way into the concrete.

As mentioned earlier, corrosion is the most common cause of deterioration of concrete tanks. The steel reinforcement corrodes in the presence of oxygen and moisture. In the water treatment facilities, chlorides in the contained water enter through the concrete and damage the passivating layer, a natural protective oxide layer around the reinforcement. The quality of concrete also plays a crucial role in protecting the reinforcement from an aggressive environment.

For structures that contain wastewater, the reinforcing rebar must be able to withstand the harmful effects of the particular chemicals present in the contained water. Coating is a traditional method engineers use to protect concrete. However, traditional materials and construction techniques cannot adequately address the aggressive environment and corrosive agents. Municipalities around the globe spend heavy resources to replace and rehabilitate corroded RC tanks.

Traditionally reinforced concrete tanks have been largely used in municipal and industrial facilities for water treatment plants for years. There are three major kinds of water tanks; underground tanks, tank resting on the ground, and elevated tanks. The underground tank is the most common type used in wastewater treatment plant. The design of these tanks requires attention when it comes to corrosion of steel reinforcement, crack control, and strength requirements.

Researchers and structural engineers are looking for innovative and sustainable solutions that can provide longer service life with minimum maintenance and repair. The FRP reinforcing bars is one such innovation which is rapidly becoming a promising alternative for RC water tanks. Because of corrosion resistance, cost-effectiveness, and improved strength, FRP composites have turned out to be a great alternative to steel reinforcement. Zero corrosion, superior tensile strength, neutrality to electrical and magnetic disturbances, and high strength-to-weight ratio make GFRP rebar a perfect material for water tanks and other sensitive waterside concrete structures.

Related: The Application of GFRP Rebar in Water Facilities: A Case Study

TUF-BAR is one of the largest producer and seller of GFRP fiberglass rebar in North America. Being a proud member of Canada Green Building Council, we focus on producing environment-friendly and sustainable construction products which include fiberglass rebar, rock bolts, form ties, and concrete anchors. Visit our site to know more about our products and their applications.

Seawater is an aggressive environment where concrete infrastructure such as seawalls, jetties, and water tanks deteriorate quickly. Corrosion of steel reinforcement or disintegration of concrete is the sign of deterioration of concrete structures. There is a number of factors affecting the deterioration of reinforced concrete in an aggressive environment. The ultimate service life of a structure and the severity of corrosion attacks depend on the environment in which a concrete member is situated.

Corrosion of steel reinforcement is one of the leading reasons why RC structures fail in marine environments. Water and salt ions penetrate through concrete cover and develop contact with internal reinforcement. This process leads to oxidation and corrosion of the rebar. Chloride-induced corrosion of reinforcement is considered as the leading cause of deterioration of concrete. The rust occupies volume and creates tensile stresses in the concrete which ultimately leads to spalling and cracking.

The sustainability and durability of RC structures particularly in marine environments remain a matter of big concern despite extensive research programs and many years of practical experience with reinforced and prestressed concrete. There are hundreds of examples of modern, steel-reinforced members that show signs of rebar deterioration providing with likely shorter serviceable lives than might be expected. In the coastal environment, corrosion of reinforcement is usually observed already after a few years and cracking/spalling of concrete occurs within 1-3 decades.

Most of the concrete deterioration has been linked to the excessive use of de-icing salts causing either salt frost attack on the concrete surface or reinforcement corrosion. Traditional rebar, no matter the protective layers or coating, cannot withstand the impact of de-icing salts and harsh coastal environments.

Sustainable marine infrastructure demands high-quality, corrosion-resistant materials. Fiber reinforced polymer (FRP) is the construction material which is not only high in tensile strength but also corrosion-resistant. FRP usually consists of fibers and polymer resin matrix. The glass fibers function as the reinforcement providing tensile strength, while, on the other hand, the resin surrounds the fibers providing corrosive resistance to the composite system.

The civil engineers are now increasingly adopting FRP technology to fight corrosion in marine structures. FRP composites have been used extensively in the recreational boating industry for more than 30 years. We are now beginning to see applications for more widespread uses of FRP in larger marine structures.

FRP composites can play a crucial role in building sustainable and maintenance free marine structures. Countries like the US and Canada cannot undermine the significance of marine infrastructure. Thorough planning and corrosion-free construction strategies can save these countries billions of dollars every year. The construction industry now clearly understands how costly it is to repair or rehabilitate deteriorated concrete members.

Rehabilitation of corroded and deteriorated members is a very expensive activity. In order to avoid costly maintenance and repair, the construction industry should start exploring and using FRP materials at large scale.

TUF-BAR designs and manufactures fiberglass rebar which is a stronger and lighter alternative to conventional steel. Our GFRP products including fiberglass rebar are specified for use in bridges, dams, barrier walls, tunneling and other sensitive marine applications. Visit our site for more information!

Corrosion is a universal phenomenon which is generally described as the deterioration of a material when it reacts with its surroundings. It is a natural process that takes place when refined metals start returning to a more stable compound. During that process, engineered materials disintegrate into its constituents atoms. The process is also called rusting.

In the presence of oxygen and water, electrochemical oxidation of metal occurs leading to rust and corrosion. Metal reinforcement used in underwater concrete pillars experiences a different form of corrosion where iron and chlorine create a reaction.

Every concrete structure has to survive in a unique environment. It is the corrosive elements that make an environment hostile and conducive to rust. Acidic soil, humidity, chlorides, alkaline and fog are some of the elements that make it hard for a concrete member to achieve its expected service life. Countries such as the US and Canada have a variety of environments and soil conditions, mostly corrosion conducive. Concrete members reinforced with traditional steel cannot withstand an environment where high acidity, salts, moisture content, and high electrical conductivity are in abundance.

We cannot limit corrosive conditions to certain boundaries; acid rain damages the environment and leads to corrosion damage beyond boundaries. Industrial pollution is also one of the factors that cause and accelerate corrosion. Governments spend trillions of dollars as annual corrosion-related costs. The construction industry has already tried many techniques such as, surface treatment, costly metals and coatings to fight corrosion. None of the traditional material and technique could sustainably resolve this long-standing issue. How can modern construction materials help civil engineers eliminate costly corrosion?

The composite materials also called fiberglass reinforced polymers (FRPs) are being widely used in military and aerospace industries where corrosion is a big concern. Following the success in previous applications, composite materials have produced incredible results in civil engineering applications. FRPs have emerged as the only sustainable solution to concrete deterioration-related problems. They are corrosion-resistant, high in tensile strength, and lightweight materials that can help structures achieve the service life of 100+ years. The unique and advantageous properties of FRPs have completely outperformed traditional steel.

FRP composites, especially GFRP reinforcement, are safe and reliable construction solutions, capable of fighting corrosive conditions in various types of environments. Being a thoroughly tested and proven technology, GFRP rebar can provide sensitive concrete structures with an extended service life with minimum maintenance. This is the main reason why composite rebar and accessories are now being increasingly used in new and rehabilitation applications. Moreover, the properties of FRP materials can be customized depending on the nature of an application.

TUF-BAR is one of the few GFRP rebar producers and sellers in the world. We produce fiberglass rebar and accessories using our proprietary patented pultrusion manufacturing process. Our products include fiberglass rebar, rock bolts, anchors, and form ties. Contact us to discuss your project and requirements!

FRP materials have turned out to be a durable solution to some of the long-standing challenges of civil engineering. Concrete deterioration, for instance, is one of the major problems the construction industry has been facing for decades. The useful service life of a concrete member usually depends on the corrosion rate of reinforcement. A structure starts corroding when aggressive elements such as chlorides and carbon dioxide penetrate the concrete and reach the embedded reinforcing steel. Corrosion of concrete reinforcement costs the construction industry billions of dollars every year.

A concrete structure may deteriorate due to inadequate maintenance, construction errors, and design. As mentioned earlier, the most common cause of deterioration in concrete infrastructure is corrosion of traditional reinforcement. Freeze-thaw attack, carbonation induced corrosion, and alkali-silica are also notable causes of deterioration.

There is a need for thorough investigation of existing deterioration so that a maintenance and rehabilitation strategy can be developed. There are specialized engineering companies which conduct investigation programs. On-site surveys and testing of materials are two major components of such investigation. The process involves detailed observation and documentation of the structure’s condition, with attention paid to the structural changes, expected service life, typical conditions and a brief survey of the structure’s environment.

During the last three decades, structural engineers and contractors have developed many repair and protection techniques. However, all of the techniques are designed to meet short-term needs. There is a difference between structural rehabilitation and protection against deterioration. The repair process involves the removal of rusted concrete, preparation of reinforcing steel and repair cavity. It is a complex task that involves the selection, placement, and curement of the repair material.

Despite the extensive research and development of several rehabilitation techniques, structural engineers are still struggling to find materials that can provide long-lasting deterioration solutions. Traditional steel cannot provide concrete structures with adequate protection against harsh environmental elements. Structures subject to corrosive environment demand corrosion-free reinforcement materials.

FRP composites have shown promising results in applications where strength, deterioration and non-conductivity are prime concerns. They have emerged as a potential solution to corrosion and other deterioration issues. Fiberglass rebar, for example, is an FRP construction product which offers corrosion-resistance, high strength-to-weight-ratio, ease of installation and other advantageous characteristics. Developed countries such as Canada, the US, and Japan have already developed design codes, guidance on the engineering, and construction of concrete members with FRP composites. This guide is a result of worldwide research and analytical work, and field applications of FRP bars.

GFRP construction materials clearly outsmart traditional materials when it comes to corrosion-resistance, durability, maintenance, and strength. This is why the structural engineers are now increasingly accepting GFRP composites as a strong alternative to conventional steel.

TUF-BAR is a proud manufacturer and seller of fiberglass bars and other durable construction products such as rock bolts, concrete anchors, and form ties. We produce high-quality GFRP reinforcement for both new and rehabilitation applications. Sea walls, dams, water tanks, bridges, buildings, research facilities, and parking garages are some of the major applications of our fiberglass rebar. Visit our site to know more about our products and see how our sustainable construction solutions can extend the service life of your next project.