Evaluation of natural composit materials in structures - Essay Example

331). In relation to structures, natural composite materials have been employed in the formation of load-bearing elements. These include roofs, beams, multipurpose panels, pedestrian bridges and water tanks. Beams are vital components in bridges, buildings and other structures. In fact, beams are considered to be structural elements that are in flexural mode or bending. They may have rectangular or square cross section depending on the requirements of a structure or even the design. Beams are commonly made of reinforced concrete, timber, laminated veneer lumber or steel profiles.

Research shows that recent developments of using natural composite beams lead to possible weight, cost, time and installation advantages. There is therefore an opportunity for the use of natural composites in the construction of structural beams. This opportunity can be also explored in construction of pedestrian bridge girders because they demand moderate design loads. The use of natural composite materials in beam construction is necessitated by the low cost and densities of natural fibres and their environmental benefits.

Among the feasible concepts of natural composites is the composite sandwich beam. The composite sandwich beam incorporates the use of several layers of materials. More often than not, the same material is utilised for the slim bottom and top section and the compact core material located in between. The core is of lesser strength as compared to the material utilized for the bottom and top. Dweib et al. (2004, p. 150-151) have analysed and formulated sandwich beams which constitute cellulose fibres that are made from paper that is reused, foam core and Acrylated Epoxidized Soy-bean Oil (AESO) which has added strength.

An I-shaped beam was another idea that was derived from the natural composite beam. Using the Vacuum Assisted Resin Transfer Molding technique, soybean oil based resin system and woven burlap (jute fabric) composite has been utilized in a successful manner to produce an I-shaped beam (Alms, Yonko, McDowell and Advani, 2009, 83). According to Marsh (2000, p. 57), the primary design methods that are normally utilized in structural design are tensile stiffness, bending stiffness, bending strength and tensile strength [36].

For some applications like roof however, impact strength is as well crucial. For polyester which is strengthened by glass fibre to be utilized as roof materials it has to demonstrate a tensile strength that is not less than 50 MPa and have no hole or crazing or cracking visible after being tested. It also has to demonstrate SREC2010-F1-5 4 impact resistance of 1.96 J in Australian standard. Roof material needs to be designed in a manner that it supports all types of loads whether it is live load, dead load and at other instances snow load.

Other features of the material are; it should be water resistant, lightweight, weather resistant (for instance ultraviolet light resistant) and fire resistant. Coming second to electricity, the roofing sector is the second largest user of glass fibre in the construction and building sector in Europe. In third rank, in terms of percentage, is the utilization of glass fibre for industrial infrastructure which includes tanks, pipes and corrosion