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.
In: Civil Engineering
what is material testing and why is important for civil engineers?
I want detailed answer with the resources.
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In: Civil Engineering
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.
In: Civil Engineering
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.
In: Civil Engineering
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: Civil Engineering
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.
In: Civil Engineering
In: Civil Engineering
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)
In: Civil Engineering
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 ⁄ .
In: Civil Engineering
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.
In: Civil Engineering
Determine the present and future peak discharge and total runoff from a 150-mm 24-h storm. If all flow in excess of the present flow must be stored, how much reservoir capacity is required? The average slope is 1 percent.
Factor |
Present Value |
Future Value |
Area m2 |
3.88 x 106 |
3.88 x 106 |
CN |
80 |
85 |
% impervious |
- |
50 |
% modified |
- |
65 |
In: Civil Engineering
In: Civil Engineering
A 4 m-wide tank with height of 1.8 m filled with water is pulled with a cable inclined at 30o to the horizontal. The constant acceleration value in the cable direction is 4 m/s². The water depth is measured as 1.5 m before the motion starts. Determine the angle between the water surface and the horizontal. Compute the maximum and minimum pressure values on the bottom of the tank. How many volume of water are spilled?
In: Civil Engineering
In: Civil Engineering
Q 1: Design a concrete mix for the following performances and ingredients:
* Compressive strength at 28 days = 32 MPa, slump 80 mm
* Crushed coarse aggregate of max size 20 mm readily available
* Fine aggregate is river sand, fineness modulus = 2.5
* Cement Strength Class = 42.5
* Specific gravity of combined aggregate =2.6
* Water absorption of coarse aggregate = 0.8%
* Water absorption of fine aggregate = 0.5%
Q 2: Design a concrete mix for the following performances and ingredients:
* Characteristic compressive strength 50 N/mm2 at 7 days
* Defective rate 1 %
* Previous control data: standard deviation 5 N/mm2
* Cement: class 52.5 * Slump required, 30-60 mm
* Maximum cement content 550 kg/m3
* Coarse aggregate: Crushed single sized 10 mm
* Fine aggregate: Uncrushed with 45% passing 600 μm sieve
* Relative density of aggregate: 2.7 (assumed)
* Volume of trial mix: 0.08 m3
In: Civil Engineering