what is compression test and why is it important when testing materials for civil engineers?

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What is the difference between free vibration and forced vibration? Derive the necessary equations and draw necessary pictures.

7–44 Reconsider Prob. 7–43. Using appropriate software, investigate the effects of the source temperature and final pressure on the total entropy change for the process. Let the source temperature vary from 30 to 210°C, and let the final pressure vary from 250 to 500 kPa. Plot the total entropy change for the process as a function of the source temperature for final pressures of 250 kPa, 400 kPa, and 500 kPa, and discuss the results.

Apply the discrete particle settling theory to calculate the terminal settling velocity of a sand particle in the water at 25°C having a particle diameter of 300 µm and a density of 2,450 kg/m3. Show the calculations and logic for at least two of your iterations.

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A concrete for a weave breaker is to be designed at a w/c ratio of 0.45.
A maximum size of aggregate of 25 mm was used hence a water content of 200 kg/m3 (with 2% air) was required to achieve satisfactory workability.
Both the coarse and fine aggregate conform to the grading requirements of ASTM C33.
The fine aggregate having a fineness modulus of 2.4, and an absorption of 2%, a BSG (SSD) of 2.6, whereas the coarse aggregate have a bulk density of 1500 kg/m3; an absorption of 3% and a BSG (SSD) of 2.50.
The moisture content for both aggregate is 2%. Compute mixture proportions (in kg/m^3) before and after moisture corrections following ACI procedure.

what is material testing and why is important for civil engineers?

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A concrete mix is required for reinforced concrete wave breaker at seashore where frequent mild freezing and thawing is dominant. A specified compressive strength of 25 MPa is required at the age of 28 days, and the size of the section and reinforcement dictate using a maximum aggregate size of 19 mm. The company had no history of testing concrete used. The coarse aggregate meets the ASTM grading requirements. It has absorption of 2%, a BSG (D) of 2.70 and a unit weight of 1550 kg/m3. The fine aggregates have absorption of 1%, a BSG (D) of 2.7 and a fineness modulus of 2.7. Both coarse and fine aggregates are used while dry. For each bag of cement (50 kg); calculate the number of containers of coarse and fine aggregate equivalent to required mass quantities. The volume of each container is 20 liters; and the loose density of the coarse and fine aggregates are 1250 and 1200 kg/m3, respectively.

A corridor connecting a suburban region to the Central Business District (CBD) is experiencing significant congestion during morning peak periods. The primary purpose of travel during the peak period is “work”, and the corridor has two main modes-drive alone (single occupant vehicle= SOV), and carpool. The city transportation engineer is considering converting a lane in each direction of travel into a high occupancy vehicle (HOV) only lane. The city officials want 2 to know what impact this proposed measure would have on current mode split in the corridor. A multinomial logit model is to be used for the analysis. The utility functions for the model are:

VSOV = 2.0 - 0.05( TTSOV) - -0.2 (TC SOV) Vcarpool = - 0.05(TTCarpool) - 0.2(TC Carpool)

TTi=travel time by mode i, minutes TCi=travel cost by mode i, dollars

Carpool =2-person carpool

Assume 2-person carpool cost is half cost for single occupant vehicle in the base condition only

The current count of vehicles in the corridor based on vehicle occupancy is:

Number of single occupant vehicles=3268

Number of 2-person carpool vehicles=532

The expected system attribute values if the HOV lane were to be implemented are:

TTauto = 20 minutes TTcarpool = 12 minutes TCauto = $7.75 TCcarpool = $3.75

i. Determine what the current mode split is in the corridor

ii. Determine what the current average car occupancy is in the corridor.

iii. Determine what the expected mode split would be after implementation of the HOV lane.

iv. Determine what the expected average car occupancy in the corridor would be after implementation of the HOV lane.

QUESTION 5
A consolidated drained triaxial test was conducted on a normally consolidated clay.
Following are the results of the test:
• Cell or Chamber pressure = 130 kN/m2
• Deviator stress at failure = 230 kN/m2
a) Determine the consolidated drained friction angle
b) What is the pore water pressure developed in the clay specimen at failure?
c) What is the angle θ that the failure plane makes with minor principal stress?
d) Determine the normal stress and shear stress on the failure plane

In construction and accordance with OSHA,

1. Cement blocks (CMU) can be used to level a scaffold frame as long as the block is placed on its side with a scaffold base plate placed firmly on it.

2. For trench and excavation safety, shoring supports should be removed from the bottom up.

3. For trench and excavation safety, closed sheeting must be used in saturated or submerged soil.

A horizontal pipe 10 cm in diameter and 3000 cm long is filled with a sand of 20 % porosity. The permeability of the sand is estimated to be 250 md. The sand is saturated with an oil of viscosity 0.65 cp, and the same oil is injected into the sand pipe. You are asked to calculate

a. What is the Darcy velocity in the sand pipe under a 100-psi pressure differential?

b. What is the flow rate through the sand pipe under a 100-psi pressure differential?

c. Calculate the oil contained in the pipe and the time needed to displace it at the rate of 0.055 cm3/sec using another fluid which has the same properties with oil but it is cheaper so that it is profitable to replace with oil.

d. If there is an immobile water saturation of 30% in the sand (i.e. water does not flow only oil flows) what will be the flow rate to oil under a pressure differential of 120 psi (assume permeability is reduced to 200 md due to presence of immobile water)

Design a wall footing to support a 30cm − wide reinforced

concrete wall with a dead load DL =293 KN/m and a live load

LL = 218 KN/m. The bottom of the footing is to be 1. 2m below the

final grade, the soil weighs 16 KN m3 ⁄ , the allowable soil

pressure, qa = 192 KN m2 ⁄ , and there is no appreciable sulfur

content in the soil. fy = 420MPa and fc′ = 21MPa, normal-

weight reinforced concrete with density equal to 23. 5 KN m3 ⁄ .

A square foundation 1.5? × 1.5? is founded at a depth of 1.5 m below the ground surface in
sand soil having a cohesion ?
′ = 0 ?? ?2 ⁄ and angle of shearing resistance∅
′ = 33°
. The water
table is at a depth of 6 m below ground level. The unit weight of soil above the water table is
? = 18 ?? ?3 ⁄ and the saturated unit weight of the soil ???? = 19 ?? ?3 ⁄ .Use the General
Bearing Capacity Equation. Determine the net allowable bearing pressure for a factor of safety
of 3.