Final Term Grades

 

The final term grades have been posted.  The following may be interesting.

• The average exam score was 86/100
• I graded the “Least” and “Most” questions myself, giving 10/10 in almost every case – you did a good job at being specific.
• I checked that there were not any multiple-choice or calculation questions on which more students got wrong answers than correct ones – which would have implied an error in the way I phrased the questions.
• Two people achieved 100/100

• The following Allowances were made before calculating the term grade

  • Attendance was adjusted
    • 1 “free” lab
    • 2 “free” lectures
  • The Lab grade was adjusted
    • The lowest lab was removed from the lab score
  • The Discussion grade was adjusted
    • The lowest discussion was removed from the discussion score
• The average class score for the term after allowances was 90%
• The grade calculated in VBB is not visible because it does not take into account the effects of the adjustments – which all increase that grade.

Exam–Least & Most Valuable Aspects of CAEE-201

I’ve just completed reading all the answers to the two questions that asked you about the LEAST and MOST valuable aspects of this course.  There were, as one might expect from 180+ short essays, a wide range of responses, but there were themes that recurred.

My Overall Impression

CAEE-201 has served its purpose for most of you. Most were happy with the course overall. Some had vehement objections to an aspect (particularly discussions), but liked other aspects a great deal. At the end you know more about the fields, the department, the professors, the kinds of calculations one makes, and what life is like in the profession.

 

Aspects that were broadly popular with no almost dissent

• The overall course – many people liked the mix of lectures, labs, site visits, discussions
• Some found particular aspects unhelpful, but were overall satisfied.
• Site Visits – almost all who mentioned them found them intriguing and beneficial for several reasons
• Motivation – they made the topic interesting
• Understanding – they made the connection between “reality” and the calculations more comprehensible
• NOTE:  The student professional societies often sponsor site visits.  For those of you who value them I urge you to join your society and take advantage of the site visits.
• Laboratories – they made understanding the practice of engineering more understandable
• There were a few who found them not beneficial, but not many
• There were specific concerns about the quality of instructions, level of consistency, frequency.
• The use of Excel as a tool was both praised and regarded as too limiting.

Aspects for which there were conflicting views

• Discussions
• As in the past there were multiple complaints that they were boring, confusing, too structured or unstructured.
• There were also many positive comments on their benefits for understanding the lectures, for dialog with other students, for exploring the field.
• My comment is that there’s probably never going to be unanimity, but I’ll stick by the idea that introducing you to the professional literature is worth the effort.  I’ll also continue to tinker with the specific requirements, attempting to incorporate some of your suggestions such as assigning a specific article for discussion
• Lectures
• Many people lauded the variety of lectures and the enthusiasm of the lecturers.
• Others were uninterested in the lectures and labs that weren’t in their particular focus area.

 

Aspects that received explicit but not wide appreciation

• Graduate Studies Panel Discussion
• Some felt it was very beneficial in helping plan their career
• Others wanted more on the non-graduate career
• Software Tools
• A number of you singled out learning specific software tools as beneficial:  Revit; Excel; ArcGIS
• Senior Design
• Quite a few appreciated the opportunity to see your future
• A number of the Business & Engineering students, however, felt it was irrelevant to them

 

Suggestions I’ll Try to Implement in Future

Many of you made specific suggestions.  The following are ones that I’ll do my best to implement in future versions of this course.

• Industry Professionals Panel – I’ll try to bring in graduates to talk about careers in industry
• Change the “Extra Credit” for labs to include discussions of related topics, current industry projects that are related, etc.
• Provide a Sample Memo & Discussion – to help people understand the format that’s expected
• Change the discussions (again) to provide more variety – discussion of a particular article is one strong idea.

Jim Mitchell

No Exam This Week

Question:

I just wanted to be clear that we do not have a final this week correct? I just want to make sure that the online final is the only part we had to take and do not have to show up to the time slot tomorrow? 

 

Response:

Correct!  There is no sit-down final this week.  The online exam is the only final.

Exam Grading

Question:

I just wanted to know how fast we are getting the grades for the final exam, since I do not know if I should to do another attempt which will be determined by the grade I have.

Response:

You won’t know the exam grade till after the exam is closed.  The point of multiple tries is twofold.

a) To give you a chance to reflect on what you answered the first time and try again if you were worried about some aspect.

b) To permit students to recover from a computer mistake – that has already happened with one student.

Jim Mitchell

Senior Design–Topic Changes

Question:

I have a quick question. I attended a senior design on tuesday 1:30 pm. The group talked about the construction of a new dorm in Drexel. When i went to the google calendar the project title says 'Design a Community Center in Chapel Hill, Maryland'. Is this the right title?

Response:

You should use what the group identified as the title for the topic since that’s the reality.

What probably is the origin of the discrepancy quite regularly happens.  During the fall term, especially, groups find that their interests have changed.  They are permitted to change their topic, but unfortunately the original title sticks for a while to the kind of information that I used to generate the calendar.

Memo for Senior Design

Question:

Quick question about the memo heading. Currently I have the heading laid out in the following format:
TO: Group #, Group Names, Advisor Name
From :My name
Date: Presentation date, presentation time, presentation location
Subject: Project title
Is this the correct formatting? Thanks!

 

Answer:

That’s fine.

Lab9–PM Concentrations

Question 1:

on question 2 where it says "3.) Calculate the average monthly PM2.5 concentration for each month in 2010, and add to the table below."
Is this just the average of what is already on the table for each month?

Response:

You are asked to calculate the average concentration for each month and insert that into column “C”

Question 2:

The table is titled PM concentration, so I'm not sure what PM2.5 concentration is.

Response:

The data in column “0” are indeed PM2.5 concentrations

Lab-9 Submission Format

Question:

I was wondering for the air quality lab, if you would prefer that the questions be answered on the Excel sheet, or if I could upload them in a separate word file?

Response:

We would prefer that you use the Excel spreadsheet to submit the labs.  It makes the grader’s life easier.

Lab-9–What’s It About

It may not have been clear what were the connections between the various parts of the Air Quality and GIS lab.  What we were attempting to do is to show how we can use ozone measurements taken at discrete sites to evaluate its level at various times and locations.

Tabs #1, 2

In the first two tabs of the lab you’re given a set of ozone measurements taken at a single point at various times.  The questions ask you to determine a variety of measures of the ozone concentrations using that data.

Tab #3 – ArcGIS work

Here we’re given (the data in the table, which Dr. Pradhan transferred to an ArcGIS file that you actually used) the ozone concentrations at a single time at twenty different locations in the Delaware Valley.  None of those locations are at Drexel, but we’d like to know what was the ozone concentration here at that time.

To estimate that concentration we use a small portion of the capabilities of ArcGIS, a professional-level program, one it might be useful to have on your resume.  The capability we used (one of many) takes a set of data that has geographic location and then creates a contour map of the ozone concentration levels for the entire area bounding the set of data points.  What you’re doing when you query for the “cell” data is asking ArcGIS to tell you the value of the ozone concentration (in this case) at a particular geographic location (the cell).

 

Taken together these tools allow you to understand how ozone (and similarly many other characteristics that vary by geographic location) varies by both time and location.  That’s fundamental to further understanding of the hazards (for ozone) for particular populations.

Lab-8 Conversion Factor Use

Question:

Do we have to use the conversion:

1 BTU = .293071 watt-h?

We found for EER that the units are BTU/kwh^2. Is this right? We are just worried that we need to use the conversion above for something, we didn't, but we want to know if that is something we are actually supposed to use.

Response:

It's often true in "real life" that you have available information that is not directly needed - sometimes its totally irrelevant and other times it's helpful for understanding, but not necessary for a specific calculation.  I'd suggest that this may well be the case with this piece of information.  If you can do the problem without using the info, then it's not required.

Lab-8 EER

Question:

I have a question for calculating the consumed electricity (Ele) in Q2 in Lab 8. The instructions have the formula:
     EER = Ecooling * Electricity     (1.1)
rearranging to:
     Electricity = EER / Ecooling    (1.2)
However, the text in the instructions says, "The efficiency of chiller can be rated by the Energy Efficiency Ratio (EER) which is defined as the cooling output in Btu divided by the total electric energy input in watt-hours during the same period..." which would lead to this formula:
    EER = Ecooling / Electricty    (2.1)
rearranging to:
    Electricity = Ecooling / EER    (2.2)
Since EER has no units, I was unable to determine the correct way of calculating the electricity.  I'm assuming it would be like 2.2, but I would like to make sure which formula to use.

Response:

• EER is defined in the instructions as Ecooling / Eelectricity – which is your 2.1
• EER is NOT a dimensionless number – the units weren’t written next to the definition but are given in the instructions.

Lab-8 Number of Plots

Question:

I just want to know if I can do three separate plots for question 3 instead of having just 1?

Answer:

We want to see them all on a single plot.  The single plot with three datasets should be generated automatically.

Lab-8 Total Airflow

Question 1:

I have a question on Quest 1. It asks for the Total Airflow Rate, when it is talking about Qv + Qr = Qe + Qr; I am kind of confused. I understand that Qv = Qe, but I'm not sure what I'm supposed to be calculating for this, the value of Qr? and what is the significance of the 7,200? I read the instructions, but I still don't understand.

Response:

The problem instructions state “Consider a system with a total volumetric flow of (Q_v + Q_r) = (Q_e + Q_r) = 7,200 m³/h.”

The 7,200 m³/h is therefore a constant which is given to you, which in turn allows you, in other parts of the assignment, to calculate Qv.

Question 2:

I also am confused about the part directly after this where it asks to perform one sample calculation for a Qv = Qe = 800 m3/h, what exactly are you asking for here?

Response:

You are being asked to calculate the items that follow on that page, the ozone and CO2 concentrations as well as the intermediate numbers for that specific value of Qv.  In Q3 you’re asked to make the same calculation for a variety of ventilation rates.

Lab-8 Temperature and Humidity

Question:

For the Energy calculation for both Ventilation and Exhaustion, I'm not sure which temperature&humidity ratio to use for each. Is it Ti and Wi for Exhaustion or vice versa? Thank you.

Response

A useful way to think about this question is to imagine a cubic foot of air going through the system. 

• Does it enter the building with “indoor” characteristics or “outdoor” characteristics? 
• Similarly does it leave the building with “indoor” characteristics or “outdoor” characteristics?

Lab-7–Dr. Montalto Notes Missing

I discovered by reading the comments to this blog that Dr. Montalto’s lecture notes are not present as I had stated.  That’s because I thought I had received them and posted them as I have with other lecturers.  I apologize to any who were affected by this.

For any student who was unable to complete the lab because they felt they needed the notes I offer the following:

• You may hand in the lab up till 10:00AM next Monday without a late penalty
• Jingjie will be present in Randel-326 at 1:00 today to answer questions about that lab as well as this week’s lab.

Jim Mitchell

Lab-7–Question-2

Question:

I am trying to figure out the equations that are needed in Quest 2, but there is no direction whatsoever of what these would be. I am confused as to what each of the columns is supposed to be equation wise. Is there anything you can tell me?

Answer:

Dr. Montalto reviewed the equations and logic in his lecture.  His slides are on VBB in the Lecture Notes folder in Resources.

Lab-7–Relation to Site Visit

Question:

In the memo grading section on the lab, it asks us to talk about the 'Relation to site visit.' Is this referring to the eiolca.com website in terms of how the data we got from it was important, or am I misunderstanding this?

Response:

Oops.  That question applies to the visit we’re making this week (week-8).  In past years we’ve visited when doing Dr. Montalto’s Lab.  I didn’t catch the change of weeks when revising. 

You may ignore that question this week.

Lab-6–Modifying Walls and Floors

Question:

When I went to annotate my longest wall, it turned out to be 111' as opposed to the 110' it is supposed to be. I must have not realized it, or it may have changed when I was creating my other walls, but I've have been trying to adjust the dimensions with no succes.

Response:

• Look in Revit Help for “Modifying Sketched Elements”.  That gives good directions.
• I found that if I’m in Plan View (Level-1) I can:
• In the “Home” menu select the wall with the “Modify” arrow
• This switches to the Modify|Walls Menu
• Use the “move” tool (Modify group in lower left corner) to drag the wall.
• It also changed the floor at the same time.

Lab-6 Revit Experienced User

Questions:

I have a question about the experienced Revit user part of the lab pertaining to the directions

Develop a model with an output "sheet" that includes the following.

• * A building model that you build for this assignment - not something from work or prior.
• * A new aspect of Revit that you haven't explored before - e.g. structural column info or a rendered view.

I am confused about the first bullet. It may be the wording, but I am unsure what it is asking to put on the sheet.

For the second bullet, I am also not sure what to place on the sheet. My senior year in high school I took a class where we spent the whole year working with the Revit program. Because we spent all year on it, I believe we learned the majority of the features. We were required to have, I believe, 4 sheets that had all 4 elevations, the floor plans, a section view, schedules for all materials, a rendered view (including the landscape we imported from another program), and the floor plan of a walkthrough. We were also required to annotate everything. I was wondering, if because of this, if there was something I was missing, or if I could just pick one that I had already done to put in. I was starting a section view when I read that it was supposed to be a new aspect, but was having difficulty with the annotations. The annotating aspects are a little different between the two versions I have used (It was either '09 or '10 that I used in high school).

 

Answers:

New Building

The intent here is simply that you do not reuse an old file from some other class or work project.  You’re to create your building from scratch.

Be sure to include all the information that the “novice” users are asked for as well as whatever new that you create.

New Aspect

Again, I’m not trying to make life too complex for you, just asking you to extend your prior knowledge.  Your example of using annotations would be fine if they’re significantly different in this version of Revit from before.  Another example would be to create your own “Family” of some object.  There’s an excellent tutorial on the Autodesk site on creating a bookcase that you could follow.

Lab-6 Revit Capabilities

Question:

First of all I have a question that is not directly to class:

• is it possible to import an AutoCAD file to REVIT in order to make a 3D disgn of it?
• The next question is the following: Is it possible to get other types of doors and windows for the design?

Response:

The answer to both is yes, although an AutoCAD drawing will import essentially as a template on top of which you can building your Revit model.

Read about Families in Revit’s help to learn about how to use many, many different building elements including doors and windows.

Lab-6 - Hints from the Lab

Below are the hints from the blackboard in the CadLab during today's session and a couple of extras.

• Save file to desktop in the cadlab to avoid using
• Email it to yourself, or use a flash drive
• Videos online are helpful if the text instructions aren't clear
• If you have only 3-4 letters in your last name - multiply by 20
• Make walls go to 2nd level 
• set "property" before  drawing, but you can change later
• Remember to put on a dimension 
• under the annotate menu
• Not all things in the videos are required for this lab

Lab-6 Which Version(s) of Revit

Question:

I went to the student site to download the software Revit.  While I was on the site i noticed a couple of different Revit programs.  After reading through the lab assignment for CAEE 201, you said to download the Revit Architecture 2012 software, but as an architectural engineering student, would it be wise for me to also download Revit Structure 2012?  Or, is it either too similar to the architecture version or completely unrelated to what I need that it's not worth it?

 

Answer:

If you pursue structural or mechanical engineering within AE you’ll want those programs too. At the moment they’re overkill. Since there’s a new version each year it’s probably not worth getting them till you’ll actually be using them.

Each builds upon a model begun in Revit Architecture and adds features that are unique to those disciplines.

Lab-5 Incremental Costs

Question:

In question 3 are we solving for the incremental cost and payback for option A or option B? I thought it was option B because the incremental cost is provided in the question. However, in question 4 it says "1) You've already calculated the construction "costs" in these two units for the two options. 2) Calculate the incremental "cost" for implementing the "green" strategy in these units". Do the "costs" refer to the CO2 and GHG emissions? And why do we have to calculate the incremental cost for the green option if it's provided in question 3?

Answer:

In Question 3 You are given the amount of rainwater that is saved by using Option-B compared to Option-A.  That allows you to calculate the incremental dollar saving in operation.

In question 4 you are indeed asked to calculated incremental cost in units other than dollars – GHG and energy. 

Please read the other posts to get ideas why calculating costs (and thus paybacks) in multiple units can be worthwhile.

Lab-5 Payback Period

Question:

In step three i got that the you only save $xxxxx a year. That seems like a very trivial amount of money to save for how much the Incremental Construction cost was. This means it would take xxxx some years to see payback money wise. Why would an engineer want to spend so much more money on this? Especially considering that it was not even any greener CO2 wise to build.

Answer:

You’re discovering why engineers perform these calculations.  It’s as important to determine what makes does not make “sense” as what does. 

What’s also important, and a major reason for this lab, is to see that using different measures of calculating the payback period can produce quite different results.

Finally, often dollar calculations of costs and benefits to the owner do not always take into account the societal costs of various projects.

Lab-5 Avoided Annual Cost

Question:

I am still confused on the section of question 4 about the avoided annual cost. What information is used to calculate these values?

Answer:

The logic of avoided dollar cost is that the “green” construction option reduces the amount of water that runs off the property.  Because the municipality charges to treat the sewer water, reducing the amount the runs off saves on the fees that the property owner pays each year.

You are given the information to calculate the average annual avoided water runoff and thus to calculate the dollars that the property owner doesn’t have to pay in fees.

Lab-5 Memo Grading Criteria

Question:

In the memo grading section on the lab, it asks us to talk about the 'Relation to site visit.' Is this referring to the eiolca.com website in terms of how the data we got from it was important, or am I misunderstanding this?

Answer:

Oops.  You’ve caught a carryover between two versions of the lab.  This “site visit” criteria is inappropriate this term (it was valid last spring) and the graders will ignore it, distributing the points as follows

• Purpose of the lab - [7 pts]
• Implications - [4 pts]
• Limitations - [4 pts]

Lab-5 Incremental Cost

Questions:

1. about Question 4. Is "Incremental 'cost'" Option B minus Option A?
2. Is the avoided annual cost the values given in the calculation instructions? If we did our calculations right should our "inremental cost" be the same?

Answers:

1. Yes
2. The incremental cost referred to is the construction incremental cost – a one-time cost which you are given – $150,000 (as I announced in class don’t use the $800K).  You are being asked to calculate the annual dollar value of the water that doesn’t run off the site.  It’s not the same thing as the construction cost.

Lab-5 Material Choice

Question:

“for question one it asks for concrete pavement but in table 3 there in not a category for it there is asphalt concrete, porous concrete, and curb concrete, which one of these do u want use to use?”

Response:

When you look in the “Assumed Raw Material” column you’ll see that “Concrete” is listed as the choice to “Concrete Curb with openings”.  That’s the line that doesn’t have a modifier for “concrete”.  Use it.

Lab-5–Why is Option-B Green?

Question:

I have a conceptual question from lab 5. In question 2, why does option B, which is the environmentally friendly option, have more carbon emissions than option A?

Answer:

Your question gets at the heart of the kind of questions engineers have the tools to answer.  The presumption is that if you “spend” a bit more at the beginning you’ll accrue savings over the life of the project that justify the extra initial “cost”?  We can measure that “cost” in many ways:  $, Energy, GHG, radiation….. 

What we can do, and indeed you’re doing it in this assignment, is evaluate the extra initial costs and the savings, and then relate them (in this case “payback”) to see whether the option is “worthwhile.”

Lab-5 LCA Analysis–Friday Availability

An Excel spreadsheet for the lab this Friday will be mounted early Friday (10/21/2011) morning before the 10:00 lab.  We’re checking the formatting and calculations to be sure that we’re giving you as well-tested a lab as possible.  Our apologies for the lateness.

Lab-4 Truck Weight

Question:

Item 6 in the instructions tells you that W is the weight of the truck, which you can calculate at this point, however the next question asks you to measure the weight of the truck. Is it asking you to do this again? Is the 'W' in 6 the same as the 'W' in 7?

Response:

Please read the text of the question carefully.  #6 does not address the absolute weight of the truck.

Lab-4 Graphing Data

Question:

I read the blog and it says i should graph the sensors data over time, i am having trouble with this is there any place i could find excel help?

Response:

In Excel-2010(PC) if you open Help (File Menu “Help”  OR F1) and search for “graph” the second entry is “Create a chart from start to finish”.  That help item (and others) will help you graph the data provided.  Note that the first column in the data is time.

You can also ask for help in Korman.

Lab-4 Appropriate Drawing

Question:

“the sketches of the bridge that are in VBB have two pages 11 and 12 with different measurements for the top chord where the sensors were placed, which pages measurments should i use?”

Answer:

I checked the smaller PDF that has only the drawings - “Tacony-Palymra Drawings”.  In that set p.11 is entitled “Approach Span Details”.  P.12 is entitled “Truss Spans Stress Sheet”.  You need to decide, based on where the measurements were taken on the bridge, which of these is appropriate.

Lab-4 Weight Calculation

Question:

I'm having a problem with the weight i am getting for the truck, and after talking to two other people they were also having problems with the weight as well. Every time i do the calculations my weight comes out to something 10^9. I am pretty sure that there is no way that the vehicle could weigh that much. I used the maximum strain on the graph of sensor 2, as well as the average for all of the sensors and still got a very large number that seems impossible. How would i take into consideration the weight of the bridge so i can find the mass of the truck only?

Response:

You’re having a problem that is quite common in the real world, and why it’s important to have a “cross-check” on the expected answer.  I’m putting several comments below that may help.

• Very often this kind of problem arises from a units issue.  Often it has to do with not being consistent (and converting where necessary) between inches and feet.
• Later Addition – Mr. DeVitis reviewed this response and agreed that the problem was probably units.  He says “This is certainly a unit issue. The measurements provided are in micro-strain [ue] and need to be converted to strain [e]. Accounting for this, his answer would be ~10,000lbs which is pretty close to the xxxxx lbs I calculated” (JEM deleted his exact answer.
• See the other blog posts for comments about the sensor location
• You should not need to take the weight of the bridge into consideration since the strain measurements start with the bridge already in place.

Lab-4 Calculation Questions

Question 1:

Where can we find the dimensional data to calculate the cross sectional area for the bride? We looked through the Tacony Palmyra drawing saved in the 'resources' folder and did not see it. We saw some things that look sort of correct but it is a bit ambiguous which to use.

Response:

This is determined by the location of the member on the bridge.  It’s why you need to know where you were.  See the other blog posts.

Question 2:

It seems to me that the average of the sensor data is the best to use because it will have the least variation, however my friend thinks that the top member is the best because it has the direct tension forces from the truck. Does it matter which sensors we use?

Response:

Both of you are right.  You can use either without problem.  Each provides advantages.  You might discuss them in the “sources of error” question.

Lab-4 Measurement Location

I’ve received several questions relating to where the measurements were taken.  Here’s a representative one:

Question:

“In the lab description we are given an example of how to calculate the cross-sectional area of the top chord. Are we supposed to know which member the measurements were taken at? The excel spreadsheet has "(ue)" next to every sensor's name. Does that have something to do with the location? “

Answer:

You were asked during the field trip to be careful to locate where on the bridge the measurements were taken, and warned that it wasn’t as simple as it might seem.  Here are several hints to help:

• For your purposes you can ignore the “ue” – you know that the sensors were all on the upper “flange” member of the truss.
• It’s OK to ask your classmates where the measurements were taken – give them credit in your lab report if you didn’t determine the location yourself.
• Refer to the drawings that are on the VBB site for assistance.  Once you’ve located the measurement location you’ll also be able to determine the components of the truss member at that location as Dr. Moon explained.
• The three truss spans are mirror images of each other.  Only one set is drawn on the plans for that reason.

Lab-4 Requirements

Question:

“While looking over the lab I noticed that there were two word documents that explain what to do for this lab.  However I noticed that they differ in the questions they ask, one is more detailed than the other, and I wanted to know what questions exactly are we looking to answer? 

• Is it the contents document or the more detailed lab description? 
• Also in what form is this lab to be submitted?  Is it a written report? Or are we to write out our calculations and hand them in in class?”

Answers:

1. The instructions in the document “T-P Lab Description 2011-10-11” are the ones that govern the lab requirements.  The “Data Explanation” document is meant to be an aid.  The questions in that document are ones that should assist in meeting the main requirements.
1. The graders will give you up to 5 points  extra credit (up to a maximum of 100 points for the lab) for answering the “Bonus” question in the “Data Explanation” document.
2. You are to submit the lab in electronic form to VistaBB.  I heartily recommend using Excel, but you may use Word or you may scan to PDF hand prepared documents (but they must be readily legible).

Lab-4–How to Start–Determining Truck Strain

Question:

“I am confused on how to start. The data given to us is about the sensor and time.”

Answer:

Please look at Prof. Moon’s description of the lab.  You’ll see in item #5 that you need to know the maximum strain.  In order to calculate that maximum strain you need to look at it over time to see an “average” when there isn’t a truck and then find the maximum when there is a truck.

Hint:

If you plot the strain (individual or average) over time using Excel you’ll almost certainly see a negative peak as well as the average that will allow you to determine strain.

L4 - Data from Bridge Visit Added to Lab 4 Assignment Submit

10/15/2011 5:50 PM Three additional files were added to the assignment that give the strain data, a picture of the truck that produced the strain data, and an explanation of what the data is and how to handle it.

Lab-3 Question about Piers

Question:

I had a question about Quest 4 & 5. Since we have two piers that make up the one pier which is being impacted by the tanker. Would you have to multiply the height by 2 to account for both piers when calculating for the Moment? I assumed that it would only have be just the height of the first pier since thats the one the tanker is actually making contact with. Does the same apply for the section modulus? would the section modulus need to be multiplied by two to take into amount there are two piers?

Answer – Prof. Dasaro:

No. You don't multiply the height of the piers by 2. They are what they are. What you adjust is the stiffness of the two-pier system by increasing the given k value by a factor of two. This is because two piers share the tanker load and the given k value is the stiffness for only one pier. You do that in Question 2.

Lab-3 File Reposted Again

Several students have written saying that the Excel file for Lab-3 wouldn’t open.  VistaBB apparently corrupted it.  I’ve uploaded and tested a clean version that should be OK.  The filename ends in “v2”  10/13/2011 7:10AM.

Prof. Dasaro’s associated lab slides are in the “Resources” folder in “Lecture Notes”

Jim Mitchell

Lab-3 Question-6 (revised)

Question:

“I am confused about Question 6 in Lab 3. When performing the back calculations, how is the value for Stage 2 deflection determined? Since, the equation is x Stage 2=(KE-PE)/P and KE is unknown, I do not see how it can be calculated. Should I use the same value I came up with in Question 2? Do I assume we don't want any Stage 2 deflection and use 0?”

Response from Prof. Dasaro

“I wanted the students to think a little.   That's why I did this” after a set of calculations that essentially recreate the lecture example.

He advises that you consider in what “region” of the stress-strain curve this stress in the pier would be located.  That will tell you something about whether you need to know the KE or not.

You’ll still need to think about what steps you need to take, but hopefully this hint will enable you to do so.

10/11/2011 07:40AM Addition from Prof. Dasaro

"Question 5 yields the bending stress in the bridge pier at the onset of unrestrained plastic flow. Compare this stress value against the 3,000 psi limitation in question 6."

Lab-3 Excel File Problem

Several students reported problems opening the file for Lab-3 (Tanker hits Bridge).  I checked and found that somehow the file had been corrupted.  I’ve uploaded a repaired version as of 9:00PM Sunday night.

Soils Lab Questions

Question

I am aware of how to calculate the total vertical stress at the points, although I am not quite sure what needs to be put in the depth column. Is it the thickness of the layer, the depth at which you first hit the layer, or the depth to which the layer stretches?

Answer:

The depth is the absolute depth below the surface at which you’re calculating the pressure – positive going down from the surface.

 

Question

I also was wondering how to go about calculating the pore pressure.

 

Answer

Dr. Sjoblom explained how to calculate the pore pressure in the lecture. His notes are online in the folder:  Resources/Lecture Notes.

Lab Template attached to Submit

For the rest of the term the files associated with the labs will be attached to the “submit” link in VistaBB. 

To get the template and any associated files (e.g. TA notes)

• Click on the “submit” link for that lab  e.g. “L3 submit”
• Download the files you need by click on them
• CANCEL the submission – you’ll come back to it once you’ve completed the lab.

Discussions–Grader’s Advice

While grading the discussions, I am noticing that the majority of the students are simply summarizing what their chosen articles say rather than weighing their personal input into the discussion thread. The purpose of these assignments to identify what the student finds the most interesting and what they are confused about, rather than reiterating the information contained in the articles? If I wanted to know what the articles said, I would just read them myself.

The interesting/confusing discussions should also be kept within the realm of the weekly topic. For example, being interested in the color of a building when looking at the structural engineering aspect is not relevant.

Also, I am finding that most students are not addressing the weekly special question directly. We suggest the following format to the class? This would make grading the discussions much easier, as well as increase the grades for the students.

First Article Title, Author, Hyperlink, etc.

• * A very brief (2-3 sentences) identification of the article’s subject
• * 1 paragraph (3-4 sentences) about what you found the most interesting about the article
• * 1 paragraph (3-4 sentences) about what you found the most confusing about the article

Second Article Title, Author, Hyperlink, etc.

• * A very brief (2-3 sentences) identification of the article’s subject
• * 1 paragraph (3-4 sentences) about what you found the most interesting about the article
• * 1 paragraph (3-4 sentences) about what you found the most confusing about the article

Special Question

• * 3-4 sentences directly addressing the weekly question

Finding Highway Bridge Info

Question:

I am having a hard time locating the data for the number of highway bridges by owner, 1996 - 2006.

Response:

Open the web link in the instruction box, and go through the web page by finding the report name with the key word of highway bridges. Open the report and the table 1 has the data you are looking for.

Jingjie Teng

Significant Digits

Question:

“what is the appropriate amount of significant figures for our calculations?”

Answer:

The significant figures in the answers depend on the significant figures in the measurements (i.e. the given values). When we are doing calculation, the rules below need to be followed:

"When multiplying or dividing measured quantities, round the answer to as many significant figures in the answer as there are in the measurement with the least number of significant figures; When adding or subtracting measured quantities, round the answer to the same number of decimal places as there are in the measurement with the least number of decimal places."

From Jingjie Teng

J. Mitchell Addition

• Intermediate calculations do NOT need to be rounded
• Conversion factors should be considered as exact unless you know they are accurate only to a limited number of figures
• e.g. 12” per foot is exact and has as many significant digits as needed.  Do not round to two digits because of this conversion factor
• Using Pi as 3.14 has only three significant digits.  Your answer should be rounded to three significant digits.

No Course Textbook

We have found no book that covers the material in this course.  For that reason there is no textbook.  Enjoy the savings!

About this Blog

We'll use this blog to post announcements and answer questions that are raised throughout this term related to CAEE-201.  We advise you to subscribe to it via an RSS reader such as Google Reader.  That way you won't have to go into VistaBB to see any changes.  There are many, many blogs available on interesting topics.  A good place to search for others that may interest you is Technorati.

Jim Mitchell