Engineered Timber Materials - Assignment Example

ENGINEERING TIMBER MATERIALS Name: Institution: Course: Instructor’s Name: Date: Timber remains to be one of the oldest structural materials ever in existence. Its use as a structural material dates back many years ago. With time, timber materials become more used for various purposes. At the same time, timber materials have been diversified through manufacturing processes to form more advanced materials called engineered timber materials (Aicher, 2013). Engineered timber products are now available in different forms, and they have improved efficiency in a great deal in the building industry. Depending on the species from which timber originates, timber is categorized as either soft or hardwood. Softwood timber originates from coniferous trees while hardwood trees originate from broad-leafed trees (Aicher, 2013). The terms hardwood and softwood do not necessarily mean that the timber is neither high in density nor does it describe the weight of the wood, but the terms are just botanical terms used to categorize timber. Softwood timber is readily available, and its cost is low when compared to the hardwood timber. The softwood timber comes from fast growing trees which mean that the wood is easier to supply from the regenerated forests areas (Aicher, 2013). Softwoods are used for timber structures. On the other hand, hardwood is used in making wall claddings and other exposed structures. The color from hardwood together with its grain patterns are the main characteristic that enables the wood to be used in the exposed structural materials as decorating components. In many countries across the world, timber was the main construction material, especially in the medieval period. Later, masonry was introduced to replace timber as demand for more durable materials grew across the building industry (Aicher, 2013). Timber was also becoming depleted which sparked environmental concerns. Use of timber as a structural component was not however fully departed as it was used in internal designs. Iron discovery also changed how timber was used in the construction of structures. Iron metals and timber were used together in supporting long span and heavily loaded structures. Types of engineered timber products Plywood Plywood is part of the engineered timber that is manufactured by gluing wood veneer into sheets with their wood grain rotated at an angle up to 90 degrees. Plywood belongs to the family of manufactured boards. In some cases, the plywood is altered by binding resin and wood fiber sheets to form a composite material that improves the tendency of wood to split when nailed at the edges (Aicher, 2013). Different types of plywood are used for various purposes: Softwood, hardwood, tropical, decorative, Aircraft, and flexible plywood, among others. Plywood also is available in different grades ranging from “A” to “BB/CC” grade. Grading is a method of categorizing plywood according to their qualities. Applications Plywood materials have existed since the beginning of World War II. Plywood is used in marine and aviation purposes for structural strengthening of its components. Plywood is also used for the stress-skin application. Laminated timber Laminated timber is comprised of some dimensioned layers that are glued together with long-lasting moisture-resistant adhesives. Laminated timber acts as a structural member used in vertical columns or horizontal beams. Laminated timber is a flexible type of timber that can be modified to different shapes. Connections in the material are mainly prepared using bolts or plain steel dowels (Aicher, 2013). Laminated timber materials can be manufactured from a variety of small trees from second and third grown forests hence optimizing the structural values of renewable resources. The ability of laminated timber to exist in different shapes helps Cross laminated timber panels Cross laminated wood panels are similar in structure to plywood only that the cross-laminated timber panels are made into prefabricated solid panels. Cross laminated timber panels are light in density due to the materials used in their structure but yet very strong mechanically. Cross laminated panels have given architects and builders an easy time as they can be used in long spans in walls, roofs, and floors. These cross laminated timber panels have superior acoustic, fire, thermal and seismic performances. Laminated veneer Laminated veneer timber is manufactured by joining thin wood veneers under intense heat and pressure. After joining, the bonded veneers are then fabricated into billets of different sizes, customized according to the buyers needs right in the manufacturing industry (Aicher, 2013). Laminated veneer and plywood are similar in how they are manufactured and are different only in the orientation of piles. Laminated veneer timber is used in framing for residential and commercial constructions. Laminated veneer timber is also used open web steel joists, and light steel beams are required. Structural forms in which engineered timber can be used: Frames Framed structures are structures that use the combination of beams, columns, and slabs to resist horizontal and vertical forces such as gravitational force. Frames are significant in the construction of structures and are extensively used to support large weights that develop as a result of applied loads in the structures. Frames exist in two forms: Planar (2D) and space (3D) forms. 2D forms have all members on the same plane while 3D frames have their members in more than one plane. Frames are also categorized on the base of the connections between the beams and columns (Reynolds, 2015). Braced frames have connections between beams and columns pinned, and their members are diagonally braced. The other type of frames on the base of connections is moment resisting frames, these kinds of frames have their beams and columns in rigid states, and they do not require diagonal bracing of their members. Cables and Arches Cable and arch structures are used to distribute loads over longer spans than trusses. A cable structure utilizes tensioned cables to support or transmit the loads of the structure to which it is offering support. Arch structures are curved structures that are used in supporting loads over a large span and normally assume a curved shape. Arch structures may be erected just for aesthetic purposes meaning that they may not carry any load with them. The arch shape is maintained by making the arch a rigid structure (Reynolds, 2015). Arch structures are made to withstand mainly the compression forces although in some cases, they are subjected to shear and moment forces. Arches are used in various structural parts of a construction project including the strengthening of bridge structures, dome roofs and also in masonry walls openings. Trusses A truss is defined as a structural framework consisting of rafters, posts, and struts supporting loads from a bridge, roof or any other structure. Trusses consist of two force members that are arranged in such a way that they form a single object. The single object formed from the arrangement of the two members ensures that force is applied only at two points. Trusses take five or more triangular units connected at joints referred to as nodes. There are two types of trusses: planar trusses and space trusses (Reynolds, 2015). Planar trusses consist of members that lie on the same plane. Planar trusses are used to support bridges with a span range of 30-40ft. Space trusses, on the other hand, consist of members making 3D extensions and are mainly used in transmission line towers. Truss members are subjected to axial forces only, and they use fewer materials to support loads but require much fabrication. Benefits of using timber materials as structural materials Timber engineered materials are natural materials. Timber does not emit toxic chemicals into the building, and it is safe to handle when building. During decay, timber completely exits the environment leaving no environmental implications to the environment. Timber is renewable. As long as people plant trees to replace the already cut trees, the materials are and will always available (Aicher, 2013). Timber also requires very little energy to get converted from wood from the forest to timber used in construction. Due to this aspect, timber is considered to embody the lowest amount of energy among all common building materials hence reduces construction cost. Timber materials are used as a natural store of carbon dioxide. Carbon dioxide consumed when trees manufacture their food is retained in their barks, and even after they are turned into timber, the carbon content remains stored in the timber for as long as the timber material exists. Timber materials are also used for insulation purposes (Aicher, 2013). Insulation is the act of reducing the amount of energy used to heat and operate a building. When used in window frames and as solid door structures, timber reduces the amount of energy requirement. Insulation as a factor makes timber an important material in the achievement of sustainable building goals. Barriers for using timber structures as structural materials Timber materials are scarce, particularly when replacements of the felled trees are not made. In such cases, timber becomes expensive to acquire hence escalating building costs. Timber materials do not last very long when compared to other construction materials (Aicher, 2013). Their lack of length in durability makes its use in construction an expensive endeavor as the worn out elements need to be accessed and replaced from time to time. Information concerning the modern timber materials and their uses is overshadowed by the use of other materials such as steel and concrete. Technology transfer becomes a challenge because many learning institutions lay more emphasis on other construction materials at the expense of timber materials. National building codes are comprised of regulations available in many countries that control how buildings are constructed (Aicher, 2013). In many countries, for example, timber buildings are not permitted beyond six stories. This creates a limitation of using timber as a material in the building industries especially where the building as to surpass the set limit. Timber as a sustainable building material compared to other construction materials. Sustainability could be described as the capability of material to be used for current use and also be availed for the future generations. Sustainability in construction industry entails conservation of materials, recycling, energy conservation and cost implications of a building system. Unlike other building materials, timber is a renewable material (Aicher, 2013). Timber also reduces the amount of carbon released into the atmosphere by storing carbon in its structure. Also, wood is used as an insulating material as mentioned earlier in the paper. Conservation of energy ensures there is sufficient energy to use by the future generations. Alternative building processes: Prefabricated houses Prefab homes have had some time in the housing sector and simply houses that are prepared in the manufacturing industries and assembled on sites (Aicher, 2013). Timber parts are measured and prepared into blocks which are then assembled in the building sites. Timber is used as the major building material because it is light and easily cut into different sizes and shapes. Mobile houses Mobile homes belong to the prefab class of houses, but they are prepared in factories then transported to their destinations by Lorries (Aicher, 2013). Mobile homes have mobile wheels which help them to change the location at will. Ecolog cottage Cowichian Valley. Ecolog cottage cowichian is a structure that is owned by Egbert who lives in Germany but uses the Ecolog cottage when on vacation. Ecolog cottage was designed and supervised by Ecolog designers and built by Randy Churchill. The building process started early 2016 and was completed in September 2016. Photo (EcoLog, 2016). Structural system sketch Load balancing (Liu, 2015) Ecolog home in Saanich Vancouver Island. Photo (EcoLog, 2010). The Ecolog home in Saanich is located near Victoria, British Columbia. The house was constructed in 2010 applying engineered timber materials in its structure (Liu, 2015). The Saanich house utilized ICF basement construction that saved large amounts of energy and had solar water heating systems installed in it. This Saanich house utilized yellow cedar and red cedar from the Cowichan Valley. Red cedar timber was used for exteriors to make the building look attractive. Structural System Structural system (Auer, 1985) Load distribution Load balancing (Liu, 2015). References Aicher, S., Reinhardt, H. W., & Garrecht, H. (Eds.). (2013). Materials and Joints in Timber Structures: Recent Developments of Technology (Vol. 9). Springer Science & Business Media. Auer, J. R. (1985). U.S. Patent No. 4,557,091. Washington, DC: U.S. Patent and Trademark Office. Buchanan, A. H., & Abu, A. K. (2017). Structural design for fire safety. John Wiley & Sons. Liu, Z., Lin, M., Wierman, A., Low, S., & Andrew, L. L. (2015). Greening geographical load balancing. IEEE/ACM Transactions on Networking (TON), 23(2), 657-671. Reynolds, P. D. (2015). Primer in theory construction: An A&B classics edition. Routle. http://www.ecolog-homes.com/projects Read More