study schedule

[squishles10]

Let me see if I can help too-

mt=mw+ms=5lb (given)

w=mw/ms=0.2 (given)

w=0.2=mw/(5-mw) (substitute for ms)

solve for mw, mw=0.83lb when w=0.2

mt=5 lb=mw+ms=0.83lb+ms

ms=5lb-0.83lb=4.17lb

ms doesn't change, because the only difference is water is added, so

w=mw/ms is now w=0.3=(mwcontained+mwadded)/4.17lb

solve for mw, mw=1.25lb

you know that the mwcontained for 0.2 is 0.83lb, and mwcontained for 0.3 is 1.25lb, so now just subtract them, leaving mwadded =0.42lb

 

[starkman]

Let me see if I can help too-
mt=mw+ms=5lb (given)

w=mw/ms=0.2 (given)

w=0.2=mw/(5-mw) (substitute for ms)

solve for mw, mw=0.83lb when w=0.2

mt=5 lb=mw+ms=0.83lb+ms

ms=5lb-0.83lb=4.17lb

ms doesn't change, because the only difference is water is added, so

w=mw/ms is now w=0.3=(mwcontained+mwadded)/4.17lb

solve for mw, mw=1.25lb

you know that the mwcontained for 0.2 is 0.83lb, and mwcontained for 0.3 is 1.25lb, so now just subtract them, leaving mwadded =0.42lb

Thanks for the questions and answers! Is it possible you could help me out on #1, it seems simple but I'm not arriving at the answer. I used the equation then solved for the dry unit weight:

total density= [1+WC(H20density)]/[WC/S+1/SG]

Got it from the CERM but it seems rather much for this problem. Thanks for any help!

 

[owillis28]

Thanks for the questions and answers! Is it possible you could help me out on #1, it seems simple but I'm not arriving at the answer. I used the equation then solved for the dry unit weight:
total density= [1+WC(H20density)]/[WC/S+1/SG]

Got it from the CERM but it seems rather much for this problem. Thanks for any help!

Here are the equations that I used to arrive at the answer

Know specific gravity, water content and saturation

Find e (void ration)?

e = ((2.68)(0.20))/0.80

e=0.67

Unit Weight (gamma??) = ((SG)(pw))/(1+e)

= ((2.68)(62.4))/(1.67)

= 100.14 lb/ft

Seems to make sense. There are a bunch of ways to do these problems.

owillis

 

[starkman]

Here are the equations that I used to arrive at the answer
Know specific gravity, water content and saturation

Find e (void ration)?

e = ((2.68)(0.20))/0.80

e=0.67

Unit Weight (gamma??) = ((SG)(pw))/(1+e)

= ((2.68)(62.4))/(1.67)

= 100.14 lb/ft

Seems to make sense. There are a bunch of ways to do these problems.

owillis

Ok...that does make alot of sense, I didn't recognize that equation when I trying to solve it. Thanks!

 

[squishles10]

Here are the equations that I used to arrive at the answer
Know specific gravity, water content and saturation

Find e (void ration)?

e = ((2.68)(0.20))/0.80

e=0.67

Unit Weight (gamma??) = ((SG)(pw))/(1+e)

= ((2.68)(62.4))/(1.67)

= 100.14 lb/ft

Seems to make sense. There are a bunch of ways to do these problems.

owillis

Huh- I didn't even think to do it like that. I did this:

w=mw/ms

S=Vw/Vv

SG=ms/(Vs*rho w)

unit weight (gamma d)=ms/Vt

now just rearrange equations and substitute, solving for ms mostly (you need the variables to cancel out in the last equation), and remember, gamma w=mw/Vw and Vt=Vv+Vs.

You end up with this equation:

gamma d=ms/[

((0.2ms/62.4)/0.8)+(ms/(2.68*62.4)]

after that its just cancelling and math.

 

[squishles10]

Transportation Questions!

A horizontal curve is going to be constructed for a paved county road in northern Michigan. The

pavement is 20 ft wide with 4 ft shoulders. The legs of the proposed curve are perpendicular. A design

speed of 60 mph is desired. What is most nearly the minimum radius needed to provide a design

where there is no reliance on a lateral friction force?

Two reverse-horizontal curves have external angles Δ1 = 30° and Δ2 = 60°. The distance between

PI and PI is 1000 ft. The maximum allowable side friction factor is 0.06, and the maximum

super-elevation rate is 0.06. What is most nearly the maximum velocity (design speed) that can be

provided while allowing for a 3 sec tangent distance between curves?

The baseline of a ramp curves to the left at a radius of 3000 ft and must clear a pier corner by 50 ft.

The pier corner is located 27 ft to the left of the curve back tangent at sta 108 + 50. What is the

station of the PC?

A new highway with a design speed of 50 mph is to be connected to an existing highway by a pair of

reverse 1° curves. The new highway is parallel to the existing highway, offset 30 ft to the right. What

is the length of the reverse curve transition, from PC to PT?

A horizontal curve is to be constructed for a paved county road in northern Michigan. The pavement is

20 ft wide with 4 ft shoulders. The legs of the proposed curve are perpendicular. A design speed of 60

mph is desired. What is most nearly the minimum length of the curve?

A ramp is to tie into an existing road at elevation 1207.44 ft, sta 16 + 00 on a 3% downgrade. The

vertical curve must clear a brick arch sewer by 4.5 ft. The sewer is 125 ft back from the tie point, and

the top of the brick arch is at elevation 1204.69 ft. The grade leading into the vertical curve is + 6%.

What is the length of the vertical curve?

The design of a high-speed train curve transition spirals calls for a maximum rate of change in lateral

acceleration of 1 ft/sec3. A curve has a radius of 10,000 ft and is to be designed for a speed of 150

mph. What is the length of spiral transition required?

 

[owillis28]

Transportation Questions!
A horizontal curve is going to be constructed for a paved county road in northern Michigan. The

pavement is 20 ft wide with 4 ft shoulders. The legs of the proposed curve are perpendicular. A design

speed of 60 mph is desired. What is most nearly the minimum radius needed to provide a design

where there is no reliance on a lateral friction force?

Two reverse-horizontal curves have external angles Δ1 = 30° and Δ2 = 60°. The distance between

PI and PI is 1000 ft. The maximum allowable side friction factor is 0.06, and the maximum

super-elevation rate is 0.06. What is most nearly the maximum velocity (design speed) that can be

provided while allowing for a 3 sec tangent distance between curves?

The baseline of a ramp curves to the left at a radius of 3000 ft and must clear a pier corner by 50 ft.

The pier corner is located 27 ft to the left of the curve back tangent at sta 108 + 50. What is the

station of the PC?

A new highway with a design speed of 50 mph is to be connected to an existing highway by a pair of

reverse 1° curves. The new highway is parallel to the existing highway, offset 30 ft to the right. What

is the length of the reverse curve transition, from PC to PT?

A horizontal curve is to be constructed for a paved county road in northern Michigan. The pavement is

20 ft wide with 4 ft shoulders. The legs of the proposed curve are perpendicular. A design speed of 60

mph is desired. What is most nearly the minimum length of the curve?

A ramp is to tie into an existing road at elevation 1207.44 ft, sta 16 + 00 on a 3% downgrade. The

vertical curve must clear a brick arch sewer by 4.5 ft. The sewer is 125 ft back from the tie point, and

the top of the brick arch is at elevation 1204.69 ft. The grade leading into the vertical curve is + 6%.

What is the length of the vertical curve?

The design of a high-speed train curve transition spirals calls for a maximum rate of change in lateral

acceleration of 1 ft/sec3. A curve has a radius of 10,000 ft and is to be designed for a speed of 150

mph. What is the length of spiral transition required?

Ready for some answers!!!! I hope I got them all right since this is supposed to be my specialty

owillis

 

[squishles10]

Ready for some answers!!!! I hope I got them all right since this is supposed to be my specialty
owillis

Good grief... good thing you did- I'm going to need help with these! I only tried one so far and I didn't get it right :-(

A horizontal curve is going to be constructed for a paved county road in northern Michigan. The

pavement is 20 ft wide with 4 ft shoulders. The legs of the proposed curve are perpendicular. A design

speed of 60 mph is desired. What is most nearly the minimum radius needed to provide a design

where there is no reliance on a lateral friction force? 3000ft

Two reverse-horizontal curves have external angles Δ1 = 30° and Δ2 = 60°. The distance between

PI and PI is 1000 ft. The maximum allowable side friction factor is 0.06, and the maximum

super-elevation rate is 0.06. What is most nearly the maximum velocity (design speed) that can be

provided while allowing for a 3 sec tangent distance between curves? 42 mph

The baseline of a ramp curves to the left at a radius of 3000 ft and must clear a pier corner by 50 ft.

The pier corner is located 27 ft to the left of the curve back tangent at sta 108 + 50. What is the

station of the PC? sta 101 + 69

A new highway with a design speed of 50 mph is to be connected to an existing highway by a pair of

reverse 1° curves. The new highway is parallel to the existing highway, offset 30 ft to the right. What

is the length of the reverse curve transition, from PC to PT? 830 ft

A horizontal curve is to be constructed for a paved county road in northern Michigan. The pavement is

20 ft wide with 4 ft shoulders. The legs of the proposed curve are perpendicular. A design speed of 60

mph is desired. What is most nearly the minimum length of the curve? 1900 ft

A ramp is to tie into an existing road at elevation 1207.44 ft, sta 16 + 00 on a 3% downgrade. The

vertical curve must clear a brick arch sewer by 4.5 ft. The sewer is 125 ft back from the tie point, and

the top of the brick arch is at elevation 1204.69 ft. The grade leading into the vertical curve is + 6%.

What is the length of the vertical curve? 3.5 sta

The design of a high-speed train curve transition spirals calls for a maximum rate of change in lateral

acceleration of 1 ft/sec3. A curve has a radius of 10,000 ft and is to be designed for a speed of 150

mph. What is the length of spiral transition required? 1100 ft

 

[owillis28]

Good grief... good thing you did- I'm going to need help with these! I only tried one so far and I didn't get it right :-(
A horizontal curve is going to be constructed for a paved county road in northern Michigan. The

pavement is 20 ft wide with 4 ft shoulders. The legs of the proposed curve are perpendicular. A design

speed of 60 mph is desired. What is most nearly the minimum radius needed to provide a design

where there is no reliance on a lateral friction force? 3000ft

Two reverse-horizontal curves have external angles Δ1 = 30° and Δ2 = 60°. The distance between

PI and PI is 1000 ft. The maximum allowable side friction factor is 0.06, and the maximum

super-elevation rate is 0.06. What is most nearly the maximum velocity (design speed) that can be

provided while allowing for a 3 sec tangent distance between curves? 42 mph

The baseline of a ramp curves to the left at a radius of 3000 ft and must clear a pier corner by 50 ft.

The pier corner is located 27 ft to the left of the curve back tangent at sta 108 + 50. What is the

station of the PC? sta 101 + 69

A new highway with a design speed of 50 mph is to be connected to an existing highway by a pair of

reverse 1° curves. The new highway is parallel to the existing highway, offset 30 ft to the right. What

is the length of the reverse curve transition, from PC to PT? 830 ft

A horizontal curve is to be constructed for a paved county road in northern Michigan. The pavement is

20 ft wide with 4 ft shoulders. The legs of the proposed curve are perpendicular. A design speed of 60

mph is desired. What is most nearly the minimum length of the curve? 1900 ft

A ramp is to tie into an existing road at elevation 1207.44 ft, sta 16 + 00 on a 3% downgrade. The

vertical curve must clear a brick arch sewer by 4.5 ft. The sewer is 125 ft back from the tie point, and

the top of the brick arch is at elevation 1204.69 ft. The grade leading into the vertical curve is + 6%.

What is the length of the vertical curve? 3.5 sta

The design of a high-speed train curve transition spirals calls for a maximum rate of change in lateral

acceleration of 1 ft/sec3. A curve has a radius of 10,000 ft and is to be designed for a speed of 150

mph. What is the length of spiral transition required? 1100 ft

For anyone that is not taking the transpo depth afternoon session, check to you exam specifics. I believe you will not see any spiral curves or any similar transpo depth type question.

owillis

 

[csb]

I need to try these out tonight

 

[owillis28]

I need to try these out tonight

Can someone post their solution for number one? I came up with a different answer and can't seem to find my mistake.

owillis

 

[squishles10]

Can someone post their solution for number one? I came up with a different answer and can't seem to find my mistake.
owillis

Well, I feel better! That was the only one I had done that I got wrong!

Here's the solution that is with the problem:

The maximum superelevation for a cold climate should not exceed 0.08 due to the potential for snow

and ice. Also, since the curve is to be designed for zero lateral friction, f = 0.

e+f= v^2/ 15R

Rmin= v^2 /15( e+f ) = ( 60 mi hr )^2/( ( 15 mi^2 ft-hr^2 )( 0.08 ft/ft +0.0 ) )=3000 ft

The equation used above is 79.37( B ) with the f requirement for snow two paragraphs below that (pg 79-7).

 

[owillis28]

Well, I feel better! That was the only one I had done that I got wrong!
Here's the solution that is with the problem:

The maximum superelevation for a cold climate should not exceed 0.08 due to the potential for snow

and ice. Also, since the curve is to be designed for zero lateral friction, f = 0.

e+f= v^2/ 15R

Rmin= v^2 /15( e+f ) = ( 60 mi hr )^2/( ( 15 mi^2 ft-hr^2 )( 0.08 ft/ft +0.0 ) )=3000 ft

The equation used above is 79.37( B ) with the f requirement for snow two paragraphs below that (pg 79-7).

Got it! I had 10 percent for paved roads in my notes. Didn't have the CERM or Green Book with me when I was working this problem. I misread the the third paragraph under "Maximum Superelevation Rates" (pp. 141, 2001 Green Book) which states "Superelevation rates above 8 percent are only used in areas without snow and ice.

I am going to have to spend some more time reading.

Thanks for the post

owillis

 

[squishles10]

AWESOME webpage for nearly everything we'll need to know in the morning! Google rocks!

http://www.webs1.uidaho.edu/niatt_labmanua...oryandconcepts/

They even have excel sheets you can download to try them!

 

[Guest]

Squishles, that is a nice website BUT please note the following ..

All of the excerpts within this chapter come from the 1994 edition of A Policy on Geometric Design of Highways and Streets,

Just make sure that the formulae are based on the same exam specification for the AASHTO Green Book.

JR

 

[squishles10]

Squishles, that is a nice website BUT please note the following ..


Just make sure that the formulae are based on the same exam specification for the AASHTO Green Book.

JR

Thanks! I do water so I never pay attention to the transpo stuff- good point!

 

[squishles10]

Yay construction questions!!!

A contract has 90 days remaining until completion. Advance completion will be paid $10,000 bonus per

day. The most critical activity duration can be shortened by employing more crews. There is a

reduction in efficiency as the number of crews increase; that is, the number of schedule days saved is

not directly proportional to the number of crews added. For each crew added, the cost is $2800 per

day for labor and equipment. If crews must be added as a complete unit, how many crews can be

added without exceeding the bonus amount? 1

crews added added crew cost per day schedule days reduced

1 $2800 20

2 $5600 26

3 $8400 30

Excavation quantities have been determined from cross sections and must be adjusted for shrinkage.

Tabulated here are the unadjusted volumes required. Shrinkage is 10%. The cut volume increases

18% when hauled in 15 yd3 capacity trucks. How many truckloads of borrow are required? 44

station cut fill

(yd3) (yd3)

20 1500 0

21 1350 0

22 800 500

23 250 950

24 0 1200

25 0 1400

A compacted fill is to be constructed with a total volume of 10 000 m . The fill is to be compacted to a

dry unit weight of at least 20 kN/m and a minimum water content of 10%. Soil in the borrow area has

a dry density of 19.0 kN/m and an average water content of 8%.

The weight of soil solids required to build the fill is most nearly 200,000Kn

A compacted fill is to be constructed with a total volume of 10 000 m . The fill is to be compacted to a

dry unit weight of at least 20 kN/m and a minimum water content of 10%. Soil in the borrow area has

a dry density of 19.0 kN/m and an average water content of 8%.

The amount of borrowed material that must be removed is most nearly 11,000 m3

Asphalt paving operations have been described as a system of four items: batch plant operation,

transporting, placing, and rolling. A contractor has a project that requires critical airport paving in a

strict 40 hr time window. Using equipment matched to the asphalt paver production rate, the

contractor's historical reliability of the equipment is shown in the table.

Due to the critical nature of the project, the contractor has decided to assign a second paver to the

job, while using the same amount of other equipment that would support a single paver. What is the

reliability of the paving system for this project? 0.93

equipment reliability

a batch plant 0.97

b hauling equipment 0.99

c asphalt paver 0.90

d rolling equipment 0.98

An asphalt paving surfacing alternative is being evaluated using the present worth for future

expenditures over an expected 40 yr life. The initial cost of the asphalt surface is $700,000. It will

require overlays at several intervals during the expected life. The cost of the future overlays will be

$252,000 at 10 yr from construction, $332,000 at 17 yr, $420,000 at 23 yr, $530,000 at 29 yr, and

$671,000 in 35 yr. The inflation rate is set at 4% annually for the analysis. What is the present worth

of the asphalt alternative? $1,550,000

 

[inspirit00]

I am in too - am taking the Transportation depth.

 

[inspirit00]

The TAMU review course material is pretty handy and also the stuff from SmartPros which was posted here, last year.

 

[Brody]

Count me in too! I also do better with structure.

Does anyone know if the Construction module is new to the breadth portion in the 2008 exam spec? I know that it is a new depth module.

I'll be doing WR depth.