FRP STRUCTURE DESIGN METHOD BASED ON THE STIFFNESS EQUIVALENCE: CASE STUDY AND PRACTICE
Article history: Received 08.05.2012. Received in revised form 20.07.2012. Accepted 03.09.2012. Nowadays, fiber reinforced polymer materials are getting widely used in civil engineering. They have some advanced engineering characteristics like high stiffness-to-weight ratio, high strength-toweight ratio, anti-electromagnetic interference, electrical isolation and their long term durability. Metal and concrete, two main kinds of construction materials, are prone to failure during their structure service lives because of environmental adverse effects and atmospheric weathering. Those harsh attacks/impacts are oxidization, acidification, high temperature and alkali corrosion. After various maintenance methods like isolating the attacks or protecting plastic skins, an interface crack between protections can easily propagate and cause some durability concern. Fiber reinforced polymer emerges in a new era of civil engineering and can surely be added to traditional materials and/or traditional materials can surely be substituted by this material. This paper sets out to unfold a case study on how fiber reinforced polymer works in civil structures.
Study and Characterization of Flexural and Tensile Properties of Hybrid Bamboo/Sisal Fiber Reinforced Epoxy Composite
Bamboo and Sisal fibers are among the most common used reinforcement materials in the fabrication of new natural fiber based composite materials. In this work, an attempt is made to fabricate, characterize and analyze the mechanical property of hybrid sisal/bamboo fibers reinforced epoxy matrix composite. The fibers were manually extracted from sisal and bamboo plants. After extraction, bamboo and sisal fibers were chemically treated with 8% and 5% sodium hydroxide respectively, to remove the extra lignin and hemicelluloses so that the bond and interfacial, shear strength of the fibres can be improved. The experiment was conducted based on Taguchi experimental method by considering weight fraction of hybrid sisal/bamboo fibers, fibers orientation and curing temperature as basic parameters which affect product strength. Hand lay-up and compression techniques were employed in the fabrication of the experimental composite. The tensile and flexural strength tests of the experimental hybrid sisal/bamboo fiber reinforced epoxy matrix composites were determined by taking samples as per the ASTM standard. The result revealed that, the bamboo–sisal fiber reinforced epoxy composites fabricated with 25/25% weight fraction of sisal to bamboo fibers, fibers stacked unidirectional and cured at 25°C demonstrate a high tensile and bending strength.
The evolution of and the way forward for advanced polymer composites in the civil infrastructure
Abstract The introduction of polymers and advanced polymer composites in the civil infrastructure has been a very rapid process in comparison to other civil engineering materials when they were in their infancy. Advanced polymer composite materials have hitherto been utilised predominately in the aerospace and marine industries, but for the last three decades there has been a growing awareness amongst civil/structural engineers of the importance of the unique mechanical and in-service properties of these materials together with their customised fabrication technologies. These extraordinary properties have enabled the design engineers to have greater confidence in the materials’ potential and consequently to use them in the renewal of civil infrastructure ranging from the strengthening of reinforced concrete, steel and cast iron, and the seismic retrofitting of bridges and columns for the use in replacement bridge decks and in the new bridge and building structures. This paper will outline the developing stages of this exciting material and will indicate future prospects for it.