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)