AIC AC EXAM - ENGINEERING CONCEPTS EXAM | QUESTIONS & ANSWERS (VERIFIED) | LATEST UPDATE | GRADED A+

1 AIC AC EXAM - ENGINEERING CONCEPTS EXAM | QUESTIONS & ANSWERS (VERIFIED) | LATEST UPDATE | GRADED A+ Sweet's Catalog Correct Answer: compiles technical construction material advertising literature published by suppliers. It is organized by Construction Specification Institute's Master Format American Society for Testing and Materials (ASTM) Correct Answer: Organization engaged in the standardization of technical specifications and testing methods American Standards Association (ASA) Correct Answer: Develops national industrial standards representing manufacturers, technical organizations and government agencies Underwriters Laboratories (UL) Correct Answer: nonprofit organization which investigatesa and tests materials, products, equipment, construction methods and construction systemsin its laboratoies. A ULAPPROVED seal of approval is recognized as a safeguard 2 What is a UL-APPROVED seal of approval recognized as... Correct Answer: ...as a safeguard against hazards to life and property. Thomas' Register Correct Answer: Compiles manufacturer's information on various manufactured products. What Materials are most widely used in the construction industry? Correct Answer: aggregates, asphalt, Portland cement concrete, masonry, steel, wood, and glass Aggregates Correct Answer: particles of random shape and size that are found in nature, such as, sand, gravel, or rock that can be crushed. Size can vary from several inches to the smallest grain of sand. Smaller than a grain of sand is considered an impurity What are aggregates used for? Correct Answer: as bases placed on top of the soil to uniformly distribute the lod over the soil for a footing or road. Riprap Correct Answer: placed at the end of culverts or along the edge of a body of water to prevent erosion. 3 Soundness of aggregate Correct Answer: aggregate quality of resisting weathering Permeability Correct Answer: the measure of the ease with which water will flow through an aggregates voids. High permeability is needed if the aggregate is used as a filter or drain Gradation Correct Answer: distribution within the range covered. Well-graded Correct Answer: sizes of particles within the entire range are in approximately equal amounts Poorly-graded Correct Answer: sizes of particles widely vary Uniform Gradation Correct Answer: a large percentage of the particles are of approximately the same size. Gap graded Correct Answer: most of the particles are of a large size or a small size with very few particles of an intermediate size. 4 Sieve analysis Correct Answer: normally graphed using the percentage retained for each gradation level and plotted on a gradation curve. The shape of the curve provides visual help in identifying the type of gradation. A vertical or nearly vertical line indicates that a large quantity of material is retained on one or possibly two sieves indicating a Uniform gradation. A line with a constant slope indicates that approximately the same amount of material is retained on successive sieve indicating a well-graded gradation A horizontal or nearly horizontal line indicates that there is no change or little chnage in percentage finer through several successive sieves. Course Aggregate (ASTM Standard C125) Correct Answer: aggregate predominately retained on the No. 4 (4.76-mm) sieve Fine Aggregate (ASTM Standard C125) Correct Answer: aggregate passing the 3/8-inch sieve, almost entirely passing the No. 4 sieve, and predominately retained on the No. 200 sieve Gravel Correct Answer: granular material predominately retained on the No. 4 sieve and resulting from the natural disintegration of rock 5 Sand Correct Answer: granular material passing the 3/8-inch sieve, almost entirely passing the No. 4 sieve and predominately retained on the No. 200 sieve Bank Gravel Correct Answer: gravel found in natural deposits, usually more or less intermixed with fine materials such as sand or clay, and normally referred to as a gravelly clay, gravelly sand, clayey gravel, and sandy gravel Concrete Correct Answer: composed of 60-80% aggregates, sand, and gravel, and 20-40 percent of active ingredients, which are water and Portland cement which produces a concrete mixture weighing 150-154 lbs/cf What is the chemical reaction that occurs when Portland cement is mixed with water which bonds it to other cement particles, aggregates and any reinforcements it may encounter Correct Answer: hydration What are the 5 types of Portland cement produced and what are their applications Correct Answer: Type I - reasonably resistant to most forms of chemical attack that might occur Type II - used where resistance to moderate sulfate attack is important, as in areas where sulfate concentration is higher than normal but not severe 6 Type III - AKA High-Early-Strength because it achieves its specified strength in 7 days rather than 28 days but there is also the corresponding increase in the heat of hydration Type IV - Low Heat - used where the rate and amount of heat generated must be minimized Type V - high resistance to sulfate attached and primarily used where the soil or ground water contains high sulfate concentrations. Water/Cement Ratio Correct Answer: Most important parameter used to control the compressive strength of concrete and determines the strength of Portland Cement concrete. Too much water will reduce strength, hardness, durability, and resistance to chemical attack, however there is a minimum of whater that must be hadded to complete the hydration of all the cement molecules. Air-Entrainment of Portland cement Correct Answer: process of adding microscopic bubbles of air which are distributed uniformly throughout the mix. Air entrainment provides resistance to freeze-thaw and to scalling caused by chemicals and freeze-thaw. Concrete Reinforcement Correct Answer: used in most structural applications because Portland cement is quite weak in tension. Usually reinforced with deformed reinforcing bar AKA rebar. Concrete Reinforcing Steel Institute (CRSI) Manual of Standard Practice 7 Correct Answer: describes the selection, use, and standard placement methods for bar supports and reinforcing bar. Bar supports are commonly known as chairs and bolsters and can be made of steel wire, plastic, or precast concrete. Types of concrete reinforcement Correct Answer: Welded Wire Fabric (WWF) - contains of wires arranged in square or rectangular configuration and welded at their intersection [MW] Deformed Reinforcing - rebar [MD] How is concrete reinforcement placed? Correct Answer: according to moment diagrams for a beam supported by two columns under typical load conditions. The beam is under tension on the bottom of the section at the mid-span between the two columns and on the top of the section over the columns therefore proper size reinforcing bar must be placed in the correct position to sustain the tensile forces. Concrete Cover over Reinforcement Correct Answer: Specified from the outside of the bar to the face of the concrete and are based on the size of the bar and location. Masonry Design and Construction Correct Answer: An established engineering approach by organizations such as the International Masonry Institute (IMA) and the Brick Institute of America (BIA) which provides the latest in engineering data, design guidelines, and construction practices for masonry construction. 8 Mortar Correct Answer: binds masonry wall units together into a single permanent struction and seals the joints against moisture and air penetration. Acts as a bond for the various components such as reinforcement rebar, metal ties, and anchor bolts. Masonry Cement Correct Answer: pre-blended by the manufacturer and includes lime, an air-entraining agent, and other ingredients to produce the desired properties Individual Proproperties of Masonry Cement Correct Answer: Portland Cement - allows Type I, II, and III when used in mortars. Airentraining Portland cement hould be used with extreme caution since it can tend to provide wide various in the actual meausred air content at the job site. Hydrated Lime - key ingredient which improves workability, elasticity, and water retention. Also improves bond strength and the mortar's plasticity, and flexibility. Shrinks the least of all the properties due to its minimual change in volume and is resistant to weather Sand - acts as a filler and contributes to the strength of the mix. Decreases the shrinkage of the mortar which occurs during setting and drying which minimizes cracking. Important to use a good grade of sand. Retempering 9 Correct Answer: The process of adding water to mortar mixs that have lost water while sitting on the mortar board. Reduces compressive strength but increases the bond strength of the mortar mix (Tech specs often limit the amount of times retempering is allowed and establishes a time limit for the use) Types of Masonry Cement Correct Answer: Type N mortar - medium-strength recommended for use in exposed masonry above grade. Type S mortar - medium-high strength used where high bond strength and lateral strength are important, recommended for use in foundations, basements, exterior walls, interior load-bearing walls, reinforced walls and non-reinforced masonry where maximum flexural strength is required Types of Masonry Walls Correct Answer: Concrete Block Wall - consists of masonry units bonded together with morter to form a load-bearing or non-load-bearing wall above or below grade Solid Brick Wall - consists of two tiers or wythes of brick bonded together with header bricks Composite wall - consists of face brick with a header brick interlocked back into a block backup wall containing header blocks to receive the header brick and regular block Insulated cavity wall - consists of two tiers or wythes of masonry separated by a continuous air space and bonded togehter using metal ties to provide water drainage 10 using flashing and weep holes. BIA recommends this construction where there is severe weather exposure, or where a maximum resistance to rain penetration is desired. Veneer masonry wall - single thickness of masonry units attached to the backing wiht corrugated metal ties but is not bonded to the backing.. Veneer wall - non-load bearing and primarily used for decorative purposes Metal ties Correct Answer: used to bind face wall to the backup wall Reinforced Masonry wall Correct Answer: consists of masonry units tied together using horizontal reinforcing wire or metal ties and vertical reinforcing bars Horizontal joint reinforcement Correct Answer: used to tie masonry units together to form a single structural unit Control joints Correct Answer: vertical joints that separate walls into sections and allow freedom of movement, occur at specified intervals in long straight walls, or where abrupt changes in wall thickness occur. Should be placed at opening, intersections of main walls and cross walls, and at locations of structural columns in main walls. 11 Bond Beam Correct Answer: a continuous, case -in-place lintel block with reinforcement bars placed in the core of the lintel block. May run around the perimeter or between control joints. Structural members which transmit lateral loads to other structural members and provide bearing for beams and joints. Lintels Correct Answer: used over opendings in block walls to carry the load around the opening Brick Positions Correct Answer: 6 different positions: Stretcher position - brick laid in a horizontal position with the longest, narrowest side facing the front of the wall (most common position) Header position - laid in a horizontal position with the shortest, narrowest side facing the front of the wall (also referred to the header course where a masonry unit is laid over two individual wythes of wall) Soldier position - laid in a vertical position with the longest, narrowest side facing the front of the wall Shiner position - laid in a horizontal position with the largest side facing the front face of the wall 12 Rowlock position - brick is laid in a horizontal position with the narrowest side or face edge placed in the bed of mortar and the longest side running back into the wall (commonly used on window sills) Sailor position - brick is laid in a vertical position with the largest side facing the front of the masonry wall Brick pattern bonds (how bricks are laid) Correct Answer: 5 basic structural bond patters: Running bond pattern - consists of all bricks laid in a stretcher position with 1/2 or 1/3 lap (commonly referred to as the stretcher bond pattern) Common or American bond pattern - consists of all stretchers with a course of header brick at a specified interval such as fifth course, sixth course, or seventh course header. Flemish bond pattern - consists of alternating stretcher and header bricks on the same course with the headers on every other course centered over the stretcher below. English bond pattern - consists of alternating courses of header and stretcher bricks Stack bond patter - consists of masonry units laid directly over one another so that all of the head joints line up in a plumb vertical position (used for decorative purposes and is structurally the poorest since there is no overlapping of units) Specification for the Design, Fabrication and Erection of Structural Steel for Buildings 13 Correct Answer: Published byt the American Institute of Steel Construction (AISC) which covers structural steel design properties with nominal dimensions and weight, and steel construction methods Erection drawings Correct Answer: issued to the contractor by the manufacturer indicating the location and proper positioning of each piece of steel within the structure. Open-Web Steel Joists Correct Answer: lightweight trusses used for supporting roofs and floors. Most common series are the K series, the LH Series, the DLH Series and the Joist Girders. Major Occupancy Classification Correct Answer: Fireproofing classification assigned to each building during the initial design states of a project due to structural steel and metal decking being extremely susceptible to fire and must be adhered too (include arena and theater, health care and detention, etc) Steel Joists Institute (SJI) and Steel Deck Institute (SDI) Correct Answer: Published specifications, load tables, and weight tables for their respective materials Welding methods Correct Answer: Two most common: Fillet weld - used to weld two pieces together that are perpendicular to each other 14 Butt or groove weld - used to weld two pieces of metel together that are set end to end or parallel to ech other (typical: Square Butt Weld, Single-V Weld, and the Single Bevel Butt Joint) Structural/Dimensional Lumber Correct Answer: Classified as common grade, rough sawn, surfaced grade, or dressed. 2" to 4" thick and 2" or wider. Further divided into: Joists are 2 to 4 inches in nominal thickness and at least 6 inches wide graded according to their bending strength on their narrow edge Planks are 2 to 4 inches in nominal thickness and at least 6 inches wide graded according to their wider dimension Light Framing - 2 to 4 inches in nominal thickness and 2 to 4 inches in nominal width/sometimes referred to as wood frame construction and consists of studs, plates, joists, and rafters Decking - 2 to 4 inches thick and 4 inches or wider, used on their their wider dimension Timber Correct Answer: Timbers are 5" and thicker and 5" and wider. Boards and dimensional lumber are known by their nominal size such as 2 x 4 which is actually 1.5" thick x 3.5" wide. Further divided into: Beams and Stringers - members with a width more than 2 inches greater than the thickness. Normally at least 4 inches thick and at least 2 inches wider than thick. 15 Installed horizontally and ranked according to the Extreme Fiber Bending stress (Fb) when loaded on the narrower of the 2 dimensions. Posts and Timbers - have a width that is no more than 2 inches greater than the thickness. Members that are either square or nearly square in a cross section. Normally installed vertically and ranked according to their Compression Parallel to the Grain (Fc//) because the loads are carried on the cross section Grades of Structural Lumber Correct Answer: Select structural grade - top grade of a species used only where high strength, stiffness, and good appearance are all required. No. 1 grade lumber - may have tiny knots but otherwise have almost the same qualities as select structural No. 2 grade lumber - may have larger knots than No. 1 but the knots are tight and the grade is excellent for floor and roof framing members No. 3 grade - still more and larger defects and can be used for sills and some plate members in residential construction. Construction grade - falls somewhere between Select strutural and No.1 and is used for extreme fiber stress in bending, standard where straightness and strength are more important, such as in concrete formwork 16 Stud grade - Stiff straight lumber with a high Compression Parallel to the Grain (Fc//) value, used for vertical walls in residential construction Standard grade and Utility grade are lower grads than stud Economy grade is used for non structural purposes National Design Specifications for Stress-Grade Lumber and It's Fastners Correct Answer: Manual published by the National Forest Products Association (NFPA) whcih includes grades established for each species of wood with allowable stresses for each grade. Stresses are derived by multiplying the basic allowable clear wood stresses by ratios Grading mark or stamp Correct Answer: Placed by the manufacturer's association on each piece of lumber which shows the sawmill number and the logotype establishing the grade rules, species, grade or stress rating, possibly the moisture content or seasoned % Allowable stresses and strengths of wood Correct Answer: Extreme Fiber Bending (Fb) stress as single member or repetitive memeber uses is the stress that must be resisted in a beam undergoing bending. The Fb value of a beam is the strength of extreme fibers in bending when a member is used horizontally, such as a floor joist, rated in psi and the beam will resist a force exerted downward at the center of the joist 17 Compression Perpendicular to the Grain (Fc_I_) stress induced by pressing the fibers together in a transverse direction Compression Parallel to the Grain (Fc//) is the stress induced by pressing the fibers together longitudinally Horizontal Shear Parallel to the Grain (Fv//) is the stress induced by the tendency for the upper fibers to slide over the lower fibers as the beam bends Tension Parallel to the Grain (Ft//) is the stress induced by pulling apart in a longitudal direction Modulus of Elasticity (E) is the measure of the stiffness or resistance to deflection whcih shows the ability to resist failure due to excessive deformation. Used to predict movement under a load and avoid failure due to excessive movement. the E value is a ratio of a load between the load of the member and the amount the member will have to deflect under the load. The higher the E value the stiffer the lumber. Plywood Correct Answer: contains thin layers or plies of wood called veneer that is bonded together with glues under heat and pressure. Plywood always has an odd number of plies such as 3, 5, or 7 and the grain is alternated and glued at right angles for max strength. B-B plyform Class I or Class II Correct Answer: Concrete grade with a high reuse factor, has a smooth surface on both sides with no splits and all the defects are plugged. The plywood is 7 layers, waterresistant and is mill oiled to resist concrete adhering to the surface. Plyfrom is also available in High Density Overlay (HDO) and Structural I grades. Class I is the most commonly available plyform. 18 Engineered grade's stamp Correct Answer: indicates the grade of the veneers, species group number, the indentification index numbers or the species group, type of plywood use, the thickness, the mill number or product standard and the type of glue specified Types of Plywood Grade Correct Answer: Grade A - smooth, has no open defects, but may have some neat repairs Grade B - solid surface with no splits wider than 1/32" and all the defects are repaired with smooth plugs Grade C - may have splits up to 1/2" and knot holes up to 1-1/2" as long as they do not affect the required strength of the plywood Grade D - poorest grade and it has a rough appearance and knots. Plywood Identification Index Correct Answer: Two numbers indicating the max span of the plywood sheet if used on the roof the second to the right of the slash provides the max span if the plywood is used for a sub floor. Force Correct Answer: push or pull on a material. The most common force in construction is the pull of gravity however other forces such as wind and water must be taken into 19 consideration. Force excerted on the surface of an object is assumed to be uniform over the internal areas of the object. Stress Correct Answer: is the force per unit area over which the force acts and is calculated by dividing the force by the areas on which it acts. Expressed as pounds per square inch (psi) or kips per square inch (Ksi) where a Kip = 1000 lbs Deformation Correct Answer: change in the outside dimension of a material caused by a force. Expressed in terms of strain. Strain Correct Answer: total change in dimension divided by the original dimension. A ratio with no units but the amount of deformation and the original lenth must utilize the same unit to provide the correct ratio Allowable Stress Correct Answer: Nothing is designed to be stressed to the point of failure so an allowable stress is selected by a factor called the safety factor Load Correct Answer: external force applied to beams and other structural forces Reactions 20 Correct Answer: reacting forces at the beam supports which counter the applied load and keep the beam in static equilibrium Load and Reactions Correct Answer: combined they can cause a beam to bend Types of Beams Correct Answer: Simple Beam - spans between two reactions located at the extreme ends of a beam Overhanging beam - beam that rests on two reactions and extends beyond one bearing point Double Overhanging Beam - rests on two reactions and both beams extend beyond the reactions Continuous Beam - supported by three or more reactions Cantilever Beam - extends from a single reaction Moment (M) of a force Correct Answer: measure of its ability to cause turning, rotating, or twisting about an axis of rotation. M can be determined as the product of a force, P, and the perpendicular distance, d, from the line of action of the force to the axis of rotation about which we can find the moment. 21 Shear Stress Correct Answer: occurs when two forces with parallel but offset lines of action act in opposite directions on the beam Vertical shear Correct Answer: shearing force that tends to cause a member to fail by cutting perpendicular to the beams's longitudinal axis Horizontal shear Correct Answer: tendency of theoretical layers in a member to slide horizontally