Civil and Environmental Engineering Answers

A block weighing 60 N rests on a horizontal floor. a) What is the minimum force that will make the block move if the coefficient of static friction is 0.20? b) What is the minimum force that will keep the block moving at uniform speed once it starts moving if the coefficient of kinetic friction is 0.10?

Design the concrete mix using the following conditions:(ACI Method)

Summarize also the total batch weights for one cylinder mold

f'cr= 28 Mpa

Water-Cement Ratio = 0.5

Non-air entrained concrete

Slump = 75 mm

No Admixture

Spec.Gravity of Cement = 3.15

Fine Aggregates

Fineness modulus = 2.80

Spec.Gravity(SSD) = 2.50

Moisture Content,% = 2.00

Absorption,% = 0.50

Coarse Aggregates - Subangular

Nominal Max.Size = 19 mm

Spec.Gravity(SSD) = 2.75

Moisture Content,% = 1.25

Absorption,% = 0.50

Oven dry-rodded density = 1700.00 kg/cu.m.

Summarize also the total batch weights for one cylinder mold

Determine the uncorrected and corrected weights based on the following data:

A.Fine Aggregates - Natural

Fineness Modulus = 2.80

Specific Gravity (SSD) = 2.50

Moisture Content,% = 0.50

Absorption, % = 1.80

B.Coarse Aggregates - Angular

Maximum size,mm = 19.00

Spec.Gravity(SSD) = 2.65

Moisture Content,% = 1.35

Absorption,% = 0.80

C.Class of Concrete = Structural

D.Cement Factor = 11.10 bags/cu.m.

E.Slump,mm = 76.20

F.Spec. Gravity of Cement = 3.15

G.Flexural Strength,Mpa = 27.50

A +4% grade line intersects a -2 % grade line at station 6+800, where the elevation is 642.40 m. as shown in the figure. Determine the elevations of 100-m stations for this 1,000-m unequal tangent curve

A construction company has an opportunity to submit a bid for the construction of a new apartment building. From the specification provided by the developer, the PERT network along with the three time estimate (in week) for each activity as shown in figure-1.

For the water shooting out of the pipe and nozzle under the conditions shown

in figure below, find the height, h about the nozzle to which the water jet will

shoot. Assume negligible head loss.

nozzle

diameter=0.1m

point A

dia=0.2m

PA=55kPa

Find the centroid of the solid generated if the region bounded by y = 2- x^2, x=0, and y=0 is revolved about the y-axis.

Find the area between the curves y^2 - y + x = 0 and y^2 = x + 3.

The city of a population of 161,565 has requested to evaluate its solids waste collection system.

Determine:

i) mean time per collection stop plus the mean time to reach the next stop,

ii) number of pickup locations per load

iii) minimum number of trucks the city must own.

Consider the following data:

a) Average truck capacity =18 m3

b) Average observed compaction ratio =3.28

c) Crew size = 2 persons

d) Number of pickups = 1/week (no rear-of-house service)

e) Average number of residence per stop= 2.5

f) Average uncompact density = 122 kg/m3

g) Average transport time to disposal site including delay and dumping = 1.5 h/trip

h) Average number of trips to disposal site =2/day

i) Rest breaks = 2 at 15 min

j) Average maintenance downtime = 36 min/day

k) Average work day = 8 hours

l) Average percentage of truck out of service for majority repairs = 15%

m) Average number of cans per stop = 2.5/wk at 0.0911 m3/can

A contractor is trying to estimate the distance to be expected of drawdown of 4.81 m from pumping well under the following conditions:

a) Pumping rate 0.028 m3/s

b) Pumping time = 1066 days

c) Drawdown in observation well = 9.52 m

d) Observation well is located 10.0 m from the pumping well

e) Aquifer material = medium sand

f) Aquifer thickness = 14.05 m

Assume that the well is fully penetrating in an unconfined aquifer.