Construction Engineering Formula Cheat Sheet

Construction Engineering Formula Cheat Sheet

Earthwork Construction and Layout

Basic Conversions

1 cubic yard = 27 cubic feet

Basic must know properties

Density of Water = 62.42 pounds per CF (pcf), 1,000 g/liter = 1,000kg/m3

Economic Haul Distance; Large Dozer up to 300 ft; Scraper 300 500 ft; Trucks > 500 ft

Excavation and embankmentGeneral Trapezoidal Formula: Area = (h0/2 + h1 + h2 + + h(n-1) + hn/2) x w

Average end area Method = V = ((A1+A2)/2) * L

Prismoidal Method = Vp = L*(A1+4AM+A2) / 6

Pyramid Method = V = AL / 3

Borrow Pit VolumesConical Spoil Pile = Vol = (Ab x H) / 3; D = (7.64V / tan ()1/3; H = (D/2) tan ( ;where Ab=base area; H=pile height;D=diameter; ( = angle of repose (deg)

Triangular Spoil Bank = Vol = Cross section Area x L ; B = (4V/(L x tan ()1/3 ; H = (B x tan () / 2 ; V= pile volume; B= base width ; H = pile ht; L = pile length ; ( = angle of repose (deg)

Density of Water = water = Mw/Vw

Moisture Content (w) = Mw/Ms

Degree of Saturation (S) = Vw/Vv

Total or Wet Density of Soil (wet) = M/V where M = Mw + Ms ; V = Vw + Vs + Va

Density of Solids = Ms/Vs

Specific Gravity = Gs = solids /water ; or = Ms/(Vs * water )

Porosity (n) = Vv/Vt ; Vv = Volume of Voids = Vw + Va ; Vt = Total Volume = Vs +Vw + Va

Void Ratio (e) = Vv/Vs

Dry Density of Soil (dry) = Ms /V

Dry Density of Soil (dry) = wet / (1+w); (dry) = (water*Gs) / (1+(w/S)*Gs)

(dry)=(water * Gs)/(1+e)

Specific Gravity = S * e = Gs * w

Porosity (n) = e/(1+e)

Void Ratio (e) = n/(1-n)

VCompacted = VBanked (1 SHRINKAGE)

VLoose = VBanked (1+SWELL)

Swell % = ((DB DL) / DL) x 100 ; Swell = (DB DL)/DL

Shrinkage % = ((DC DB) / DL) x 100 ; Shrinkage = (DC DB)/DL

DL = Dry Loose unit wt (pcf) ; DB = Dry Bank unit wt (pcf) ; DC = Dry compacted unit wt(pcf)

Vloose = Vc (1+Swll)/(1- Shrinkage) ; Vbank = Vc / (1-Shrinkage)

Site Layout and Control Height of Instrument (HI) = Known elevation + Backsight (BS)

Turning Point (TP) = Height of Instrument (HI) Foresight (FS)

Trigonometric Leveling ( Elevation at unknown location = elevation at known + HI + (slope distance sin (angle of slope)) distance from known to unknown location

Traverse Area: Method of Coordinates ( The area is A = (Sum of full line products Sum of broken line products)

Earthwork Mass Diagrams Rising section = cut; Falling section = fill; zero slope = moving from cut to fill or vice versa

Estimating Quantities and Cost

Quantity take-off methods

Trenching: Be careful to fully understand what the dimensions represent, Use horizontal In-In and Vertical Out-Out

Estimating # bricks in wall : net wall (sf) = Gross surface Area of Wall (sf) Area of open surface (sf) ( then find surface area of brick with mortar (sf) ( (net wall / SA of one brick) x # rows = bricks in wall

Volume of mortar per brick = (mortar thickness)(brick width)(length + height + mortar thickness)

Board feet = Thickness(in) x Width (in) x Length (in) / 144

Rebar = When finding the number of rebar bars in wall = (the length of wall / spacing of bars) + 1

Cost estimating

Engineering economics

Present/Future Value: F= P(1+i)n or P = F/ (1+i)n ; i= (F/P)1/n 1 Series Payment : P=A[(1+i)n- 1]/[I (1+i)n] ; F=A[(1+i)n- 1]/[i] Future/Present Value and Arithmetic gradient: F=G/i[((1+i)n- 1)/i)-n] ; P=G(i(1+i)n- iN - 1)/(i2(1+i)n]

Depreciation:

Straight Line Method : Dn = (Initial Cost Salvage Value)/ NSum of the years Digit Method: Dn = (n2 + n)/ 2 Declining balance Method: Dn = 2 x (1/n) Construction Operations and Methods

Lifting and RiggingSolve for Center of Gravity: Ax = (A1)(x1) + (A2)(x2) + + (An)(xn) ; where A= Total Area

x = distance to the CoG in the x direction, A1 and A2 = Area/Volume or Mass; x1 and x2 = distance to the CoG

Crane selection erection and stabilityCrane Stability: Factor of Safety against toppling = Resisting moment / Toppling moment

Toppling Moment = (Weight of Load(WL)) x (Distance from toppling pt to Load)(LL) + Weight of boom(WB) x Distance to Center of Boom(LB)

Resisting Moment = = (Weight of Counter Weight (WC)) x (Distance from toppling pt to Counterweight)(LC) + Weight of Crane Body(WG) x Distance to Center of Crane Body(LG)

Dewatering and PumpingEquipment ProductionDozer: Total Time = Q / (P x N) : Q = Quantity of material to be moved; P = hourly production rate per dozer; N = Number of Dozers

Grader: Total Time = (P x D) / (S x E): P= number of passes required; D = distance traveled in each pass, in miles or feet; S = speed of grader, in mph or fpm (multiply mph by 88 to convert to fpm; E = efficiency factor

Scraper: Total time (hours) = Q / P x N ( Q = total volume to move(BCY), P = hourly production rate (BCY/hr), N = number of scrapers

Loader: Maximum production rate (LCY per hour) = heaped bucket capacity x bucket fill factor x 60 minutes/ loader cycle time (min) ( Net production rate (LCY per hour) = maximum production rate (LCY per hour) x efficiency factor

Excavator: q = ((3600 sec/hour x B x E x P)/ C) x Volume Correction ( q = Volume of soil excavated and dumped in a truck by the excavator (CY/hr), B = Bucket struck capacity (CY), E = Bucket efficiency factor, P = Productivity factor, C = Cycle time for 90 degree angle and optimum depth

Compactor: Production (CCY per hour) = (16.3 x W x S x L x E) / N ( W = compacted width per pass (in feet), S = compactor speed(mph), L= compacted lift thickness(in), E = efficiency, N = number of passes required

Compactor: Compactors required = FD x SCF / CP ( FD = amount of fill delivered (LCY per hour), SCF = soil conversion factor (LCY:BCY), CP = compactor production (CCY per hour)Dump Truck: Number of trucks required = 1 + truck cycle time (minutes) / loader cycle time (minutes)

Productivity analysis and improvementsTemporary Erosion ControlIV. Scheduling (17.5%: ~7 Afternoon questions and 1/2 morning)* Construction SequencingCPM Network AnalysisActivity Time Analysis* Resource Scheduling* Time Cost Trade offV. Material Quality Control and Production(10%: 4 Afternoon questions and 1 morning)* Material Testing(eg. concrete, soils, asphalt)

Welding and Bolting TestingQuality Control Process(QA/QC)

Concrete Mix Design- (Q&A)

VI. Temporary Structures (12.5%: ~ 5 Afternoon questions and 1 morning)* Construction LoadsFormworkFalseworkand Scaffolding Shoring and ReshoringConcrete maturityand early strength evaluation

BracingAnchorageCofferdam (systems for temporary excavation support)

Codes and standards (e.g. American Society of Civil Engineers(ASCE37), American Concrete Institute(ACI 347), American Forest and Paper Association NDS, Masonry Wall Bracing Standard)

VII. Worker Health, Safety, and Environment (7.5%: ~3 Afternoon questions)OSHA RegulationsSafety ManagementSafety Statistics(e.g., incident rate, EMR)

VIII. Other Topics (10%: ~4 Afternoon questions)Thesetopics are actuallysomeofthe depth sections for theother Engineering modules. As you can see there is a lot of material to study forjust four questions that will be asked. These things are worth looking overbut I wouldnt spend to much time studying these sections.

Groundwater and well fields (Groundwater control including drainage, Construction Dewatering)

Subsurface exploration and sampling (drilling and sampling procedures)

Earth retaining structures (a. Mechanically stabilized earth wall, b. Soil and rock anchors)

Deep foundations (a. Pile load test, b. Pile installation)

Loadings(a. Wind, b. Snow, c. Load paths)

Mechanics of materials(Progressive Collapse) - in-depth courseMaterials (a. Concrete(Prestressed concrete, post tensioned), b. Timber)

Traffic safety( Work zone safety)