Friday, June 13, 2014

Best and Worst Aspects of Course–Your Opinions

I’ve just completed grading the essay question that each of you completed on the exam.  I’m happy to say that all of you took it seriously and thus almost everyone received a “10 out of 10”.  Only a few people had entries that were too short or not read for grammar, thus losing portions of a point.  One or two, sadly, did not complete the question at all and thus received no points.

Since I use this question as a prime way of learning what’s good about the course and what needs improvement I keep a tally while grading of “Best” things and Worst things.  Here’s a summary of what I learned.

Best Aspects of the Course – by number of mentions above 5
  • The diversity of the course, introducing you to all aspects of what the department does - 35
  • The lectures – mostly for their variety and enthusiasm – 35
  • Discussions – 25 (though 3 disliked them)
  • Site Visits – 22
  • The labs – generally (and see below for problems) – 15
  • Course design overall - 8
  • Connection of theory to reality - 6
  • There were quite a variety of aspects with fewer than 5 mentions including specific lecturers, specific labs, aspects of the administration
Worst (or problematic) Aspects of the course
  • Various aspects of the labs, though a maximum of 6 in each area
    • Lack of detailed rubrics, guidance on some labs
    • Lab instructions not clear
    • A variety of aspects with less than 5 mentions including: Discussions, lab instructions, dull lecturers, specific labs.
Some Statistics
  • 48 people chose to write exclusively about the Best
  • 2 chose to write exclusively about the Worst
  • 31 chose to write about the best and worst
  • Longest essay – 624 words
  • Average essay – 276 words

To get a sense of your overall satisfaction with the course I rated each essay on a 1-to-7 scale with one being “intense dislike” and seven being “best course of the term” – a four being neutral.  Using that scale your rating was 6.1 out of 7 overall.  I will look at the course evaluations when you complete them to see how they match this rating.

Here’s a link to the overall Final Assessment Comments

Take-Home Assessment – Comments

Some of you may wish to know how the class performed on the final Take Home Assessment. Here are some comments

The Process
  • I graded all the essay questions myself – almost everyone was careful and received full credit
  • I reviewed the “item analysis” provided by BbLearn.  It looks at the performance on each question to see if there problems because they were poorly written or possibly required material that was not presented in class.
    • As a result of that review I decided to add 8.7 points to each person’s raw score to make allowance for possible lack of clarity, although I found no questions that I felt were wrongly stated.
    • The result of this increase in the exam is reflected in the column –CAEE-201 TakeHomeAdj
Some comments on questions where there were difficulties.
  • Learning after Graduation – It’s almost certain that you’re going to need to go on learning throughout your career as an engineer.  Many of you chose answers that indicated your thought there wouldn’t be much later learning.
  • Heat Transfer Calculation – this was the same basic question as in Lab #1
  • Nested IF Function – This was admittedly a difficult question, but it was directly based on the hydrology lab.  Learning to use this kind of logic will almost certainly be beneficial in your engineering career.
  • Gas Concentrations – A key result of the IAQ lab was that you cannot have all things – low ozone and low CO2 merely by ventilating.
  • Revit Type – Revit is BIM software, not a sketching or drafting tool.  When I Googled the word Revit the first entry stated that as I did in class.
  • EER – EER is a ratio of BTU/Watt-Hour – It’s a measure of efficiency of an air conditioning system.  it is NOT dimensionless as it is used. 
  • Member Weight Calculation – It’s surprising that a number had difficulty with this one.  You needed to calculate the volume and multiply by the density, being sure to watch the units of volume to work in either in^3 or ft^3.
Short Essay on Best or Worst Aspect of CAEE-201

I covered this in a separate post

Wednesday, June 4, 2014

Units for Bridge Lab–Sources for Calculation Problems–Dimensions and Micro-Strain

There are two potential sources of error on the bridge lab, one of which is probably not as obvious as it ought to be.

#1 Consistent Units

It’s easy to forget to convert your lengths into consistent units – usually inches.  That often introduces big errors.

 

#2 Micro-Strain

The data for the lab are marked “ue”.   It is probably not obvious that this means the real strain is 10^6 times smaller than shown in the excel spreadsheet.  It’s shown that way in the spreadsheet to avoid showing many, many zeroes before the significant digits.

So: a strain shown on the spreadsheet as –1.23 ue  is really –1.23/10^6 = 0.00000123

Lab-9 T-P Bridge Questions

 

Questions

Are these problems that need to be done for the lab? 

(2) Monitor the strain gage data under traffic and inform the engineer operating the data acquisition system when a truck approaches so they can record the strain time-history.

(3) Take a photograph of the truck that caused the measured strain in the top chord and note the lane (upstream, downstream or center) it occupied. 

      (8) Is the computed truck weight less than the legal limit?   (Where are we to find the legal limit?) 

Added Later

And is the max stress level the values in the one in the -30 range or in the 4-5 in/in range

 

Response

#2 & #3 – We provided the strain gauge data and the truck photograph this time

#8 – As Dr. Moon said in his lecture and I said in class today you can find this by a Google Search looking for Federal truck weight load limit or something similar.

Max Stress Level – It’s up to you to determine the max stress level.  Usually a maximum (in absolute terms) is the greatest departure from the average.

Tuesday, June 3, 2014

Bridge Calculation Question

Question

I find the figure 'Truss Chord Diagram' very confusing. Specifically, I am unsure as to where each label is referring to in regards to the information in the 'T-P Lab Description' file. 

The description states:

One Cover Plate: 28 in. by 1/2 in. è Area = 28in(1/2in) = 14 in2

Four Angles: 6 in. by 4 in. by 3/8 in. è Area = 4*(6in(3/8in)+4in(3/8in)) = 15 in2

Two Webs: 24 in. by 1/2 in. è Area = 2*(24in(1/2in)) = 24 in2

Two Plates: 12 in. by 5/8 in. è Area = 2*(12in(5/8in)) = 15 in2

I would like to know where these pieces are, as I see two labels for Web Plate 1 and Web Plate 2 for example, and do not understand which label goes to which piece. 

Follow-On Question

My confusion is more about the difference between a "webplate" and "web" and "plate." The diagrams show "Webplate" but the information in the attached description lists these separately. 

 

Response

The Truss Chord (The top one for your problem) is a “built-up” member composed of a series of steel pieces.  The “example” in the instructions for the lab is supposed to help you understand how to read the labeling on the drawings.  Our expectation is that you’ll look at the drawings and find the label that is similar to the one in the example for the truss chord where the strain gauges are labeled.  You then calculate the cross sectional area of the truss chord as in the example.

There is a diagram in the documents attached to the assignment that shows the typical assembly of a top chord.

To perform the calculation you don’t actually have to know where each piece is in the built-up member, although it’s nice to be able to interpret the code to be able to visualize it.

Web is the technical term for  the long middle piece between the two shorter parallel pieces in an “I” or “H” structural member.  Flange is the term for the shorter pieces.

Webplate probably should have been two words meaning “a plate that forms part of the web of a built-up member”

About the Online Final Assessment

Where Do I Find It?

  • Click on the “Quizzes and Exams” menu item in the course website in BbLearn

When It’s Available

  • Opens – Midnight Thursday Morning  6/5 
  • Closes – 11:59PM Sunday Evening 6/8

How Much Does It Count?

  • 18% of the total grade

What is on it?

  • 75% Multiple Choice + True/False + Multiple Answers (more than one answer per question possible)
    • These are drawn from the lectures and the labs in the course.
    • A few require you to be careful in your thinking, but most are straightforward.
  • 15% – Calculation Questions based on the labs
    • The description and logic for calculating the answer are the same, but each student will see different numbers
  • 10% – 200 words or more on the Best or Worst (or Both) Aspects of CAEE-201 – graded on being specific, not on your opinions.

May I take It More than Once?

  • Yes, you may take it up to three times – each time you have 3 hours
  • You will not receive your score after taking the assessment– not until I have graded the essays after the assessment closes
  • You may not save and resume during one instance of the test.
  • Each time you take it the numbers for the calculations and the order of the questions will probably be different.
  • You should assume that we will use the grade from the last instance that you take the assessment.

Lab-9–Tacony-Palmyra Bridge Questions

Questions

#1 What files do we submit to Bb Learn for this assignment? If it is a singular Excel workbook, then are we to create the Memo sheet from scratch? If not, what other files are we to complete?

#2 When analyzing the strain values from the sensors, I noticed that a lot of them, including the largest ones, are negative. Does this imply that the strain is in compression? Are we to use these larger negative values in our calculations and disregard the negative sign?

#3 Which distribution factor are we supposed to use? Are we to use just one? Or do we calculate the weight of the truck three separate times for all three scenarios?

 

Responses

#1 – As in any work situation you are to submit what is required to address the problem.  We left it more open.   If it were me, I’d submit a single Excel sheet using what I’d learned from the other labs.

#2 – Think about the truss and how it bends.  The bottom wants to stretch and the top wants to compress.  Negative values indicate compression.

#3 – You are to look at the information provided and decide which lane the truck is in and thus which distribution factor is appropriate.