Sunday, February 8, 2015

Structural Depth Practice Exams



Structural Depth Practice Exams
    How do you prepare for the structural depth exam? How much time should you allot to review for the structural PE exam?
    The structural depth exam is the toughest option for the PE exam. You will want to acquire and take as many structural depth practice exams as you can before the date of your PE exam. The following are the best options, according to reviews by other exam takers.
    One of the first things you want to do is to take a practice exam. Set aside the full amount of time you will need to complete the exam. Be sure to choose your question answering system. The e-book Pass the PE like a Pro explains the two main strategies (lion or fox) and why one is greatly superior to the other and will almost certainly make a positive difference in your final score.
    The first practice test will provide a baseline for your strengths and weaknesses. The areas of the Structural Depth module are:
The following paragraph is taken from a review on Amazon: 


So I set the CERM companion aside and started working from this sample exam, and it was a world of difference! These are much more representative of the problems one should expect to see on the PE. The majority of problems are easily solved within 6 minutes and there are no multi-part problems, just as the exam is formatted. This book restored the confidence that the CERM companion stole. –A. Henley (on Amazon)


    Henley is correct. The best, most representative questions will be found in the NCEES Structural Sample Questions and Solutions book. So, this is the first book you want. It is the first sample exam you want to take. This book has 40 questions from the morning breadth and 40 questions in the afternoon structural format. 

    You can take only the afternoon portion, if you are hard pressed for time. But, you really should take the full 8-hour exam. Taking the full exam requires 9 hours; lunch takes one hour between the two portions of the exam. Here is the format: 

8:00 a.m. to 12:00 noon- 40 breadth questions covering all topics.
12:00 to 12:55 p.m. – Lunch (and a quick nap if you have time and a reliable phone or watch alarm.)
12:55 to 1:00 – Sit in your chair inside the exam room waiting for the afternoon structural depth portion.
1:00 to 5:00 – Afternoon structural depth problems

    Once you complete it, you will have a feel for the quality of the kind of questions you will find on the exam. You will understand how you need to study. And, you will have a score to compete against, to improve upon, while studying. The reason you should take the full 9-hour format is fatigue. The mind, like muscles, depends on the body system to provide what it needs to operate. It can fatigue. So, the afternoon portion includes a level of tiredness which you should build into your study program. If you take the afternoon portion alone, without working the morning problems first, your score will be slightly inflated. But, it will show your strengths and weaknesses either way.
    Every person is competitive. Something to beat provides inspiration. Schedule a second practice exam for two weeks later. This forces you to keep your scheduled study sessions. Knowing you will have another practice exam will keep you honest. You will want to show improvement; this will be motivating and increase confidence.

Here is a graph of results from one examinee who took and passed the structural afternoon exam:



The score you will need to pass will depend upon how difficult the particular exam you sat for was. A team of professionals “fine tunes the passing score based on the exam’s difficulty.” However, most sources that mention a percentage (few do) say that approximately 60% is a passing score. However, because of statistical variance, set the bar higher. You want to score 70% correct on a practice exam before your actual exam date. 


    Here are additional options for the structural depth exam: 

1.   Structural Depth Practice Exams for the Civil PE Exam. (May 6, 2014). This 96-page book contains two afternoon exams. These contain afternoon structural depth exam problems. There is no morning portion. But, you can supplement one of these with Mike’s Civil PE Exam Guide: Morning Session to create one full exam. The second practice exam you can take in an evening and score and review during the next few days.
2.   Six-Minute Solutions for Civil PE Exam Structural Problems. (July 15, 2014). Review rating: 4 stars. 108 pages. 80 structural depth problems and another 20 thrown in for the morning breadth portion.
3.   Structural Engineering Reference Manual. (May 15, 2014). This is not a practice exam. But, as it is cousin to the Civil Engineering Reference Manual. It has an average 4.6 star review on Amazon. This is very high for an engineering review book. Anything better than 3.2 is good. Anything over 4.0 is gold.
4.   Steel Design for the Civil PE and Structural SE Exams. (March, 2012). Contains 50 examples and 35 practice problems. These focus on steel design and connections. If you are weak in this area, this is a must-have.
5.   Structural Engineering Solved Problems. (November, 2011). 100 structural practice problems. Note: uses AISC 13th edition (one edition stale, but not that big a deal with the Steel Manual); uses LRFD Bridge Design 2010. But, it covers bridge design, which is somewhat lacking in other options.
6. AASHTO LRFD Bridge Design Specifications. (2012). This is a spiral bound version of the standard for the design and evaluation of bridges.

Monday, February 2, 2015

PE Exam Sample Question, Structural



How to Calculate the Compression Capacity of a Steel Column 

... the easy way.

Examinees lose the most points in the structural questions. Here is a tip for answering structural questions. Many questions can be answered using tables in AISC 360, the "Steel Construction Manual."
For example, look at Table 4-22. For any section, convert to KL/r (L in inches) and then use the table to find the maximum axial compressive load (Fcr in ksi). Multiply Fcr by the cross sectional area of the column and that is the capacity.
Problem:
Given:
Column = HSS 6x6x1/4
Material = A500 Grade B, Fy = 46 ksi
Column Height = 18 feet, no bracing
K = 0.8
Find:
Maximum axial capacity in compression

Solution:
1.) Look up the r value in Table 1-12 of AISC. r = 2.34 inches. Also note the area of the cross section for later. A = 5.24 square inches. (page 1-93 of the steel manual)
2.) Calculate KL/r = (0.8)(18ft x 12"/ft) / (2.34) = 73.8
3.) Use Table 4-22 (page 4-323). Find the column for Fy = 46 ksi. Within that column, find the sub-column for KL/r on the left. Follow the KL/r column down to the value closest to 73.8, which is 74. Now, follow the row to the right. You will see two values. The ASD value is 19.1 ksi (highlighted green in the 14th edition) and the LRFD value is 28.6 ksi.
4.) Multiply Fcr x A = 19.1 x 5.24 = 100,100 pounds maximum capacity in axial compression.


Notes:
* Linear interpolation within the table is permitted. (But, the precision of the answer choices on the exam will not likely require it.)
* If you use Euler's equation, there are several checks you would have to calculate rather than the two simple ones in this procedure.
* This example uses a bi-symmetric section. The X-X and Y-Y axes have the same r value. If you had a Wide Flange or other section, you must check both axes and use the lower r value.
* L is the least braced length and can differ from one axis to the other.
* 35 ksi: railing (A53, Grade B carbon steel)
* 36 ksi: pipe, angles, channels (A36)
* 42 ksi: round HSS (A500 Grade B)
* 46 ksi: square and rectangular HSS (A500 Grade C)
* 50 ksi: W shapes, WT shapes (A572, A992)
* Notice that omega-o and phi-sub-c are already applied to the values for Fcr. Do not apply these reductions a second time. 
* Tables 4-1 to 4-12 can be used for specific sections of plain steel. 
* Tables 4-13 to 4-15 can be used for axial compression capacity of concrete-filled hollow sections. 
* Share this with your friends!

Buy AISC 360, 14th edition Steel Construction Manual

Structural Engineering Exam SE Practice Problems books