The Construction Dictionary/ Glossary

New words added ; Updated on 03/09/2013!

This post has been compiled in order to increase awareness and provide theoretical knowledge within the construction industry in particular equipment. A list of definitions used frequently by experts and some popular formulas will allow one to capture aspects and grasp concepts within this field; information that matters in your daily site operation and decision making process.

This list will be updated every week or two, so stay tuned!

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Abbreviations

  • ANSI; American National Standards Institute
  • BCY/BCM; Bank Cubic Yard/Bank Cubic Meter
  • BIM; Building Information Modeling
  • CCY/CCM; Comapcted Cubic Yard/Comapcted CubicMeter
  • CICE: Construction Industry Cost Effectiveness
  • CM; Construction Manager
  • EIS; Environmental Impact Statement
  • ICC; International Code Council
  • ICT; Information and Communications Technology
  • ISO; International Organization for Standardization
  • LCY/LCM; Loose Cubic Yard/Loose Cubic Meter
  • OSHA; Occupational Safety and Health Administration
  • QA; Quality Assurance
  • QC; Quality Control
  • QM; Quality Management

Dictionary

  • Activity-based costing (ABC); an accounting term that aims to price an activity (product or service) by allocating indirect costs and adding them to direct costs. This method is more accurate than traditional methods even though time consuming.
  • Actual life; the period of time the machine is actually owned.
  • Aggregate processing plant; generates aggregates and material from excavated rocks and gravel. Raw material loaded and hauled to the plant can be crushed, screened, sorted, blended or washed. Aggregates produced are mainly used in asphalt and concrete mixes. The processing plant receives raw material through the feeder into the jaw crusher, which is the primary crushing process. The secondary crushing step, made possible through roller crushers, follows and treats large stones before screening aggregates according to different size ranges.
  • Articulated hauler; is a concept first introduced by Volvo BM, currently Volvo CE, in the 1950’s. An articulated hauler is an equipment that is used to haul earth on all kind of terrains, and can cope best with low-trafficability soils; soils that are very soft and muddy for instance. An articulated hauler has a greater versatility and higher speeds than traditional dump trucks. It consists of a tractor and dump body that are connected trough a rotating hitch that allows all tires to stay on the ground and thus avoid slippage. The hitch allow the machine to both bend and rotate.
  • Asphalt paver; refer to Paver.
  • Backhoe loader; is a concept first introduced by Joseph Cyril Bamford known as JCB in 1953. It is a merge between a wheel loader and an excavator. It is mostly suitable for soft to medium conditions. It has great versatility and maneuverability as it can serve a big number of applications thanks to it’s lift arms and bucket on front, and the boom, arm and excavating bucket on the back.
  • Basement construction; is a designation of a building’s construction that allows one or more full stories below ground level, to be used as basements.
  • Batching; is the first step of producing concrete. It is the process during which the different components required to mix concrete are proportioned adequately.
  • Breakdown repair; a series of technical works and missions that aims to restore a malfunctioned machine to its normal working  mode.
  • Breakout force; is the force exerted by the edge of the bucket and is generated by the bucket cylinder. The force is tangent to the radius drawn by the end of the bucket.
  • Building construction; (aka vertical construction) is one of the two major categories within the construction industry consists on the construction of buildings; wether residential/non-residential, public or private.
  • Bucket fill factor; is a unit-less number that is derived based on studies and simulations on different materials. This factor is used to estimate the productivity of excavators by calculating the volume of material a bucket can practically hold. This number is multiplied by the heaped volume (maximum volume) of the bucket.
  • Compaction; is the process during which soil loses the void and air particles within, and thus have its density increased. Compaction is possible through the use of soil compactors that allow the soil to become more uniform and rigid before laying asphalt and paving for instance. The drum of the soil compactor delivers high frequency vibration.
  • Concrete; is produced by mixing portland concrete, aggregates such as limestone or granite and water. Some chemical or mineral additives can be used to improve workability and extract specific properties of the concrete. The process behind producing concrete involves batching, mixing, transporting, placing, consolidating, finishing and curing. Many types of concrete can be found in which density can vary, each for specific application. Some types of concrete are lightweight insulating concrete, mass concrete that does require little or no steel reinforcement, heavyweight concrete used to shield nuclear radiation, and refractory concrete used under very high-temperature applications.
  • Crawl space construction; is a designation of a building’s construction in which the first floor of the building is suspended less than one floor’s level height higher than the ground, and that is to ease access to utility lines.
  • Crushing plant; refer to Aggregate processing plant.
  • Depreciable life; life used in depreciation accounting.
  • Diesel engine; is one type of internal combustion engine that is found on heavy equipments. Power is generated by burning diesel instead of gasoline, for instance, as can be seen in commercial cars. The combustion in diesel engines does not happen with the help of spark plugs but by the sole action of compressing hot air in the combustion chamber.
  • Displacement; is a term used to describe hydraulic pumps. It defines the volume of fluid (oil) moved by one cycle of the pump. It should be noted that displacement is not necessarily fixed in a pump; it can also be variable.
  • Down-time; the period of time when a machine is not operating due to malfunction.
  • Dozer, bulldozer; is a concept first developed by Caterpillar in the early 20th century. It consists of a tractor equipped with a blade attached on its front and allows to move earth thanks to its remarkable traction power. Several blades design can be equipped on the dozer each for a particular application. A dozer can be both tracked or wheeled. A tracked dozer has a much greater pushing power, but less versatility and maneuverability on roads compared to a wheeled dozer.
  • Drawbar pull; is the traction power that a crawler machine can deliver. Manufacturers provide charts of the drawbar pull curves versus different operating conditions.
  • Earth-moving; is the process of moving soil and rocks from a place to another for the purpose of preparing a site or a land to meet construction specification and design. Earth-moving processes are mostly excavating, grading, hauling, loading, finishing, compacting.
  • Economic life; optimum time that the equipment should be held from an overall income/cost viewpoint.
  • Excavator; is a construction equipment that comes in different sizes; from compact to large and heavy machines. The machines  has a boom, arm or stick and a bucket that are driven hydraulically. The cab, engine, pumps and the rest of the hydraulic complements are part of the superstructure of the machine and sits on the undercarriage. The latter combines the tracked chains or wheels in addition to the drive/ travel motors. The cab can rotate 360 degrees on the undercarriage. The main components on the excavator are: engine, hydraulic pumps, main control valve (MCV), swing motor, travel motor, cab and finally the pistons holding the boom, arm and bucket. Excavators can have several attachments installed given the first is fitted with an additional hydraulic function. Hydraulic breakers, cutters, crushers and grabs are common examples of attachments.
  • Finish grading; follows grading and consists on making the soil smooth and shaping ditches.
  • Fixed-displacement pump; is a hydraulic pump having a fixed displacement.
  • Foundation; of a structure refers to both the structural design that holds the load and transmits it to the supporting ground and the soil or rock upon which the structure rests.
  • Grade-ability; is a slope, expressed in percentage value, that a machine can climb.
  • Grading; is the process of bringing earth and soil to a desired level and shape.
  • Ground pressure; is the weight of the machine divided by the surface area of the ground supporting the machine.
  • Hauling; is the process of transporting earth and material through the use of trucks, wagon or carts.
  • Heaped volume; refers to the maximum volume of material an excavator’s bucket can hold without spillage.
  • Heavy construction; (aka horizontal construction) is one of the two major categories within the construction industry. This division captures all sort of construction other than construction of buildings; such as bridges, airports, road construction projects, dams, tunnels to name a few.
  • Hot-mix asphalt (HMA) paving; is the highest level of asphalt pavement. It is mainly used in airport runways, highways and streets. HMA paving is made possible by first spreading the hot-mix and compacting it. HMA trucks unloads their loads on the asphalt pavers. The asphalt pavers are designed to push the trucks through their from push-rolls, while the truck is unloading. Paver initially compacts the placed pavement. Having paved the HMA, the mix should be compacted immediately using asphalt roller compactors.
  • Hydraulic motor; is responsible of converting the pressure generated by the pumps in to mechanical movements in most cases. For instance, hydraulic motors allow the swing and travel movements on an excavator.
  • Hydraulic pump; is at the heart of the operation of construction equipment. It is responsible of delivering pressure to the system and thus achieve movements of the pistons or hydraulic motors.
  • Information and communication technology (ICT); as the name suggests, ICT refers to all technologies referring to information management and project communication
  • Kaizen; is a Japanese model/philosophy that stands for “continuous improvements” in any industry, in particular manufacturing. Kaizen was applied after the Second World War by Japanese firms first, in particular Toyota, before being implemented and adapted by other international firms. This philosophy relates to a great extent with “Lean”. Refer below.
  • Lean; allows a firm to maximize the product or service value for customers by increasing quality, reducing costs and eliminating wastes.
  • Lift force; is the capacity of a machine to lift weights and is generated by the arm cylinder.
  • Loadability; defines a characteristic of the soil by measuring how easy or difficult it is to excavate and load the soil. Loadability affects to a great extent the excavation costs and time. The harder and compacted the soil is, the more time and wear on the machines will the earth require to be moved.
  • Loader; consists of a tractor on with a bucket is equipped. The bucket is attached on lift arms and can be titled inwards and outwards. A loader can be used for earth moving, stockpiling, loading, hauling and several other purposes. A loader can be both wheeled or tracked. It should be noted that wheeled loaders are more popular that tracked loaders.
  • Motor grader; is an equipment that has a long blade equipped use for finishing, stripping, grading and trimming mostly. The grader has a wide use in highway construction. It allows flattening and maintaining haul and highway roads before compaction.
  • Net present value (NPV); is a financial term, used to assess the viability and profitability of a investment or business idea. It calculates the numerical value of a possible investment by projecting a series of cash inflows and outflows resulting from the investment over a specific period of time. This value takes into consideration the time value of money as money now has greater earning power than money in a year from now for instance.
  • Operating cost (of a construction equipment); covers the cost of maintenance and repairs, operating conditions, horsepower ratings, fuel consumed and lubricants. Operator cost is excluded from the operating cost of the machine.
  • Operating hour; the period of time during which a construction equipment/machine is running, whether operating or running idle.
  • Ownership cost (of a construction equipment); covers the cost of money (i.e. interest rate for money invested), the depreciation of the equipment, taxes on the equipment, insurance costs and the storage expenses.
  • Paver, Asphalt paver; are machines used to spread the asphalt mix during the paving process. The paver can either be wheeled or tracked. Some people describe the paver as an orchestra since the paving operation cannot be completed unless all paver’s operations work with synchronization. The paver is made of two principal units; the tractor and screed units. The tractor unit allows the paver to propel and to push the hot-mix asphalt truck while unloading its content, through its front push-rollers. Also the tractor units allows the mix to travel through the conveyor to the screed unit. The screed unit, on another hand, allows the HMA to spread transversely through the augers. Also, the screed allows the paver to deliver the HMA on different elevations, keep the mix warm through heaters and provides initial compaction. It should be mentioned that common screeds can have its width extended from 2 up to 9 meters.
  • Power by the hour (PBH); this concept is a trademark of Rolls-Royce plc. According to the PBH, the owner a heavy equipment is charged a fixed hourly fee by the dealer of provider of the equipment, that would cover all maintenance and repairs resulting from break-downs of the machines. This would allow the owner a much accurate definition and understanding of his costs. This would help greatly the owner in setting a price for the his services (see also Activity-based costing, ABC).
  • Ready-mixed concrete; refers to the concrete being mixed and transported directly in the truck mixer. Concrete elements are introduced in the truck mixer at the batch plant.
  • Relief valve; is a common component in a hydraulic system. It sets specific pressures on different part of the hydraulic system. The maximum pressure delivered by the pumps can thus be lowered on some lines while left higher on others; that is achieved by allowing excess pressures to return to the tank.
  • Retarder; is a hydraulic device that is used to control the speed of a machine when driving down a slope. It is used in order to reduce the wear on the service brakes. Retarder is very common on articulated haulers.
  • Rimpull; is a common term used to describe the pull available at the rim of a wheeled machines under standard operating conditions. Performance charts are available to show the changes of the rimpull vis-a-vis the gear engaged, taking in consideration different operating conditions.
  • Rock ripping; is the process of breaking up the soil. It is considered as the cheapest way of breaking up the soil. This process can best be accomplished with a dozer.
  • Rolling resistance; is a term used to calculate the total resistance that drags a loading or hauling machine. Total Resistance helps calculate the maximum travel speed of the machine. Rolling resistance is directly linked to the flexing behaviour of the tires and the penetration between soil and tires. Rolling resistance is found to be the lowest on firm grounds such as asphalt and the highest on muddy and soft soil.
  • Shovel; or hydraulic shovel is a machine that is very similar to an excavator, in terms of design and hydraulics, except that the bucket is facing outward (not towards the bucket). A shovel is very efficient when digging on the track level or above compared to an excavator that is more versatile when digging on the ground level.
  • Shrinkage; is the opposite phenomenon of Swell, explained below. Soil in bank or loose condition will reduce its unit volume once compacted. Air will be forced out of the soil particles under compaction.
  • Skid-steer loader; is a another type of loader first introduced in the 1950’s. It is a small loader having one rigid compact body. A skid-steer is a machine that gained popularity thanks to its remarkable versatility, speed and productivity. It’s operating and maintenance costs are relatively low and that is because of its small size. The skid-steer application is limited to soft material handling.
  • Slab-on-grade construction; is a designation of a building’s construction in which the first floor of the building is on the ground level.
  • Soil; is the natural upper layer of earth. It is a mixture of minerals and organic matters. It consists of five main matters, that depends on their proportion define a specific behavior and characteristic of the soil; gravel, sand, silt clay and organic material.
  • Superpave; is a new design and construction system of asphalt paving. Superpave is sponsored by the US Congress and developed by the Strategic Highway Research Program (SHRP). Superpave was introduced to improve the paving process and achieve lower failure of asphalt pavements. Superpave mainly differ from the conventional HMA in that it uses stiffer mixes obtained by using smaller and less rounded crushed aggregates in addition to a lower asphalt content in the mixes.
  • Swell; is the phenomenon during which soil in bank (natural) condition gains volume after being excavated, loaded and then hauled. That is due the fact that excavated soil will gain air and void within after being removed from its natural condition.
  • Taxable life; life used for tax purposes.
  • Trafficability; defines a characteristic of the soil and is used in the construction environment. It describes the capacity of the soil to allow traffic to circulate over. This term accounts primarily to the soil type and moisture condition. This term is mostly used in construction projects where soil is left unimproved given earthmoving machines access these roads. Construction companies pay particular attention to trafficability when selecting the machine fleet.
  • Truck mixer; is a truck capable of mixing and transporting concrete to the unloading site. The truck is equipped with a rotating drum capable of holding 5m3 up to more than 12m3 of concrete. Truck mixer should be discharged from the ready-mixed concrete one and a half hour (1.5hrs) after mixing starts and before 300 revolutions of the drum. It should be noted that truck mixing requires between 70 and 100 revolutions for concrete to be ready.
  • Utilization, Machine Utilization; the percentage of time the machine is being operated over the maximum available time during which the machine can be utilized.
  • Variable-displacement pump; is a hydraulic pump that can have its displacement increased or decreased throughout its operation depending on the load on the machine. Changing the displacement of the pump is achieved through a regulator built on the pump, thanks to a feedback system. Excavators usually have what is know as negative feedback, while wheel loaders have a positive feedback. The feedback is called load sensing, since it senses the load.

Some formulas and equations

  • Production of an equipment = Volume of earth moved per cycle x Cycles per hour
  • Production of an excavator = Cycles per hour x Swing-depth factor x Heaped bucket volume x Bucket fill factor x Job efficiency; where Swing-depth factor depends on the swing angle and the depth of the excavation, Heaped bucket volume depends on the bucket installed on the excavator, Bucket fill factor depends on the behaviour of the material excavated and the Job efficiency depends on other indirect factors that relates most to managerial and organisational behaviour within the company.
  • Cost per unit of production = Equipment cost per hour / equipment production per hour

References

  1. Dun & Bradstreet; http://www.dnb.co.uk/
  2. Fan, H and Jin, Z. (2011). A Study On The Factors Affecting The Economy Life Of Heavy Construction Equipment. Department of Building and Real Estate, The Hong Kong Polytechnic University. 27 (1), p923-928.
  3. Featured picture courtesy of  Advantage Group Insurance.
  4. Nunnally, S (2007). Construction methods and management. 7th ed. Ohio: Pearson Prentice Hall.
  5. Nunnally, S (2010). Construction methods and management. 8th ed. Upper Saddle River, N.J: Prentice Hall.
  6. Peurifoy, R, Ledbetter, W and Schexnayder, C (1996). Construction planning, equipment, and methods. 5th ed. New York: The McGraw-Hill Companies, Inc.

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