This set of Civil Engineering Drawing Multiple Choice Questions & Answers (MCQs) focuses on “Classification of Timber, Carpenter’s Work”.
1. ___________is a type of wood that has been processed into beams and planks, a stage in the process of wood production.
Explanation: There are two main types of lumber. It may be supplied either rough-sawn, or surfaced on one or more of its faces. Besides pulpwood, rough lumber is the raw material for furniture-making and other items requiring additional cutting and shaping. It is available in many species, usually hardwoods; but it is also readily available in softwoods, such as white pine and red pine, because of their low cost.
2. One among the following is the insect and mollusc which is not responsible for the decay of timber-
a) Marine borers
d) Woodboring beetles
Explanation: Timber decay (rot) is caused by a biological attack within the wood by certain species of fungi. The fungus can lie dormant in the timber for years until the right conditions present themselves. The conditions needed are oxygen, moisture and nutrients, with moisture being the critical component. If moisture is not present in timber, then the fungi will remain dormant, even when oxygen and the nutrients they require are abundant.
3. There are two main natural forces responsible for causing defects in timber: abnormal growth and ____________________
a) rupture of tissues
Explanation: Rupture of tissue includes cracks or splits in the wood called “shakes”. “Ring shake”, “wind shake”, or “ring failure” is when the wood grain separates around the growth rings either while standing or during felling. Shakes may reduce the strength of a timber and the appearance thus reduce lumber grade and may capture moisture, promoting decay. Eastern hemlock is known for having ring shake. A “check” is a crack on the surface of the wood caused by the outside of a timber shrinking as it seasons.
4. _______________is a skilled trade in which the primary work performed is the cutting, shaping and installation of building materials.
Explanation: Carpenters traditionally worked with natural wood and did the rougher work such as framing, but today many other materials are also used and sometimes the finer trades of cabinetmaking and furniture building are considered carpentry. Carpentry in the United States is almost always done by men. With 98.5% of carpenters being male, it was the fourth most male-dominated occupation in the country in 1999, and there were about 1.5 million positions in 2006. Carpenters are usually the first tradesmen on a job and the last to leave.
5. A _______________is a carpenter who does fine and detailed work specializing in the making of cabinets made from wood, wardrobes, dressers, storage chest, and other furniture designed for storage.
a) Scenic carpenter
b) Log builder
c) Trim carpenter
Explanation: A cabinet is a box-shaped piece of furniture with doors and/or drawers for storing miscellaneous items. Some cabinets standalone while others are built in to a wall or are attached to it like a medicine cabinet. Cabinets are typically made of wood, coated steel, or synthetic materials. Commercial grade cabinets, which differ in the materials used, are called casework.
6. The vertical timbers include _______and wall studs.
Explanation: A wall stud is a vertical framing member in a building’s wall of smaller cross section than a post. They are a fundamental element in frame building. A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member.
7. Wood contains water in three forms- vapour, bound or hygroscopic water and____________
a) contact water
b) capillary water
c) free water
d) bulk water
– Free water: The bulk of water contained in the cell lumina is only held by capillary forces. It is not bound chemically and is called free water. Free water is not in the same thermodynamic state as liquid water: energy is required to overcome the capillary water. Furthermore, free water may contain chemicals, altering the drying characteristics of wood.
-Bound or hygroscopic water: Bound water is bound to the wood via hydrogen bond. The attraction of wood for water arises from the presence of free hydroxyl (OH) groups in the cellulose hemicelluloses and lignin molecules in the cell wall. The hydroxyl groups are negatively charged. Because water is a polar liquid, the free hydroxyl groups in cellulose attract and hold water by hydrogen bonding.
-Vapor: Water in cell lumina in the form of water vapour is normally negligible at normal temperature and humidity.
8. Rough lumber is supplied in standard sizes, mostly for the construction industry
Explanation: Finished lumber is supplied in standard sizes, mostly for the construction industry- primarily softwood, from coniferous species, including pine, fir and spruce (collectively spruce-pine-fir), cedar, and hemlock, but also some hardwood, for high-grade flooring. It is classified more commonly made from softwood than hardwoods, and 80% of lumber comes from softwood.
9. Dimensional lumber is lumber that is cut to standardized width and depth, specified in inches.
Explanation: Carpenters extensively use dimensional lumber in framing wooden buildings. Common sizes include 2×4 (pictured) (also two-by-four and other variants, such as four-by-two in Australia, New Zealand, and the UK), 2×6, and 4×4. The length of a board is usually specified separately from the width and depth. It is thus possible to find 2×4s that are four, eight, and twelve feet in length.
10. Laminated veneer lumber (LVL) comes in 1 3⁄4 inch thicknesses with depths such as 9 1⁄2, 11 7⁄8, 14, 16, 18, and 24 inches, and are often doubled or tripled up.
Explanation: They function as beams to provide support over large spans, such as removed support walls and garage door openings, places where dimensional lumber is insufficient, and also in areas where a heavy load is bearing from a floor, wall or roof above on a somewhat short span where dimensional lumber is impractical.
11. Wood with less than 25% moisture (dry weight basis) can remain free of decay for centuries.
Explanation: Fungi attack timber when these conditions are all present:
-The timber moisture content is above 25% on a dry-weight basis
-The environment is sufficiently warm
-Oxygen (O2) is present.
12. The seasoning of lumber is typically either kiln- or air-dried.
Explanation: Wood drying (also seasoning lumber or wood seasoning) reduces the moisture content of wood before its use. When the drying is done in a kiln, the product is known as kiln-dried timber or lumber, whereas air drying is the more traditional method.
13. Green carpentry is the specialization in the use of green timber.
Explanation: Green carpentry is the specialization in the use of environmentally friendly, energy-efficient and sustainable sources of building materials for use in construction projects. They also practice building methods that require using less material and material that has the same structural soundness.
14. Carpenters normally framed post-and-beam buildings until the end of the 19th century; now this old fashioned carpentry is called timber framing.
Explanation: Timber framing and “post-and-beam” construction are traditional methods of building with heavy timbers, creating structures using squared-off and carefully fitted and joined timbers with joints secured by large wooden pegs. It is commonplace in wooden buildings from the 19th century and earlier. If the structural frame of load-bearing timber is left exposed on the exterior of the building it may be referred to as half-timbered, and in many cases the infill between timbers will be used for decorative effect.
15. Box frame is a simple timber frame made of straight vertical and horizontal pieces with a common rafter roof without purlins.
Explanation: The term box frame is not well defined and has been used for any kind of framing other than cruck framing. The distinction presented here is the roof load is carried by the exterior walls. Purlins are also in a simple timber frame.
Sanfoundry Global Education & Learning Series – Civil Engineering Drawing.
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