Properties of Construction Materials

Field Trip to Metriguard

2009-12-07T19:54:00.000-08:00

Field Trip to Metriguard, Pullman, WA ...

Metriguard manufacturers machines for testing and rating lumber (Machine Rated Lumber). The machines are sold and serviced all over the world.

Pictured is General Manager James Allen explaining to UI CE 357 students how the machine in back of him E-rates lumber. Though the machines were idle during our visit, we are told that the machine in back of him rates 3 pieces a second and can shoot them out the end across the parking lot (back door open, presumably).

Thank you, Metriguard for the tour.

Dr. Bayomy Delivering Asphalt Lecture

2009-11-11T16:24:00.001-08:00

Dr. Fouad Bayomy, P.E., our Asphalt Expert - and who normally teaches this course - giving a fabulous overview of asphalt as a construction material and asphalt binder.

We will hear more from Dr. Bayomy on Friday.

Don Parks

2009-11-10T13:23:00.000-08:00

Don, getting us ready for tensile tests in Con-Mat ...

Go Don!

Composites

2009-11-09T19:48:00.000-08:00

Okay - I put a `sanitized' version of our talk today on the web:

http://serioushunter.com/edu/engr/357/composites.htm

In it I placed a link to a slideshow from a guy I know (even though he probably doesn't know I scooped up his slideshow) on FRP (or FiRP ... Fiber Reinforced Glulam).

I Also expanded somewhat on the author's (course text) on reinf. in concrete (see red).

Doc

Second Exam ...

2009-11-05T11:42:00.000-08:00

... more of a long quiz, really. Should be easy if you have good notes. There are a few minor calculations, so bring a calculator. As mentioned in the review session ... `no calcs' means no long, drawn out calcs like a complete mix design, or the calculation of Py, or ... etc.

Aluminum ...

2009-10-30T18:18:00.001-07:00

So, here is my outline for our talk (or non-talk) about Aluminum. Read the book. Consider that I will hold you responsible for the book materials, and (especially) stuff (emphasized) in the outline.

(Here)

Steel Lecture ...

2009-10-26T15:55:00.000-07:00

Okay, in html format, is today's lecture ...

10/26 Steel (Lecture 1) ...

Some of this is from the book, some is fun, and some is from other sources.

Tomorrow - beam break day!

Fineness Modulus ...

2009-10-23T13:13:00.000-07:00

Okay, if we look at the def. on p. 184, we see the words `sum of the cumulative' percentage weight retained. What this means is that a bunch of sand with larger particles is gonna get more stuff hung up early, which gets counted again and again in the `summing of cumulative' process - thus higher FM means larger particles. Alternately, if the `handful' of sand is all really, really fine, and say it all pass through the sieves and gets hung on the one at the end (bottom), we will get a smaller cumulative amount, and thus smaller FM.

... that's why, then, Table 7.5 for example, demands less coarse agg in a mix with higher FM ... I think.

Table 5.5, Text

2009-10-23T13:08:00.001-07:00

Table 5.5 in the text is rather cumbersome. Think of the left hand column as simply being the `name' of the coarse aggregate. So, "Coarse Agg No. 1" ... and so on. So, for a pile of aggregate that has nominal sizes pieces 1 in. and less, there are several `names' (sizes) to choose from. Choose the size that best fits your sieve analysis, and then describe how well (or not) your stuff meets the distribution in the Table, for that size.

Agg and Paste ...

2009-10-22T11:21:00.001-07:00

I couldn't resist ... here is the aggregate (noodles) and paste (Alfredo sauce) before placing in the microwave (for curing).

Sieve Analysis Progress Report ...

2009-10-21T13:03:00.000-07:00

... a couple people have asked about the `Predicted' part of this report. You can see in the Outline (here) that I changed the wording slightly to `Anticipated Results' ... and then go on to suggest language along the lines of the gradations falling in the limits of Table 5.4 and 5.5 of the text. You could leave out this section of the report, but if you do - you should still discuss the lab results with Tables 5.4 and 5.5 and the suitability of our stuff for use in Portland Cement Concrete.

Con*Mat Students ...

2009-10-20T20:58:00.001-07:00

Hey - I appreciate the way you people are `jumping in' during lab and getting things done! "Good Job."

Update ...

2009-10-20T16:17:00.001-07:00

Okay - lab went well today. We accomplished all of what I wanted to get done in Lab and on Wed and Friday (provided we did it all right). As such, on Wed and Fri we will meet in TLC 223 at the regular lecture time and I will simply be available to help you with calcs and reports.

Doc

Lab Today ...

2009-10-20T13:14:00.001-07:00

Okay, ... the procedure today in lab basically follows Experiments 7, 8, and 9 in the Appendix of the Text. The only info values hanging are the oven dry weights, which Adam will email. With that the information we should be able to get what we need by the `cook book' equations in the Text.

Also: someone in Sec 02 left a calculator. (I have it now.)

Doc

Cook's Question ...

2009-10-19T12:50:00.000-07:00

Yeah, list all the Code Issues, even the ones not addressed ...

(Addressed ...)

1. Strength - YES (Safe Service Load P)
2. Serviceability - YES (Deflection issues)
3. Bar Cover and Spacing - YES (I gave you values in class ... )
4. Extension of Reinforcement into Supports - YES (as discussed)

Deal with as `Not Addressed'

5. Min. Reinforcement
6. Max. Reinforcement
7. Development Length
8. Additional Embedment (Terminated Rebar)
9. Bar Size / Pullout
10. Splices

Progress Reports

2009-10-19T12:47:00.000-07:00

Yes, I do still like you all - even though it may seem otherwise with all these `Reports'. They are not as bad as they might seem - and do keep you on track. The Due Date for the Beam Break Calcs is 10/28 ... I should make it earlier - so you can indeed go into the lab with the numbers the beams should break at ... so maybe I'll make it earlier, or later, ... in the mean time, work on these others:

... from the Course Schedule, updated ...

10/19 Progress Reports on Concrete Lab:

Early Break of Cylinders

Sieve Analysis (Coarse and Fine) (See Experiment 6, Text Appendix)

Strength and Deflection Calcs

10/20 LAB: Specific Gravity and Absorption of Coarse Aggregates
Specific Gravity and Absorption of Fine Aggregates

10/21 Bulk Unit Weight and Voids (Experiment 9, Text)

10/23 Bulk Unit Weight and Voids

Thank You - GREG

2009-10-14T20:00:00.001-07:00

Gang, our very own Greg Elmore send me some pics from his gig in Iraq. Thank you, Greg, for serving our country.

...

Sieve Analysis Lab ...

2009-10-14T08:07:00.000-07:00

So, I told my students - "Look, the last time I did this was probably before you were born - so I won't pretend to be an expert, and not even a novice. So, Don (Parks) is gonna tells us about sieve analysis, and lead us in the Lab."

Here the students are going at it.

These are a good bunch of kids - they jump right in there.

One thing I `got' from Don's talk was about the issue of scale. I generally work on relatively small projects, where small differences are generally `no big deal'. But on big projects (miles and miles of highway, for example), little differences ADD UP!

Sec 03 Early Break Data ...

2009-10-12T15:02:00.000-07:00

I just emailed out the raw data for the early break of the Sec 03 cylinders (that we did last week). The third test data numbers look suspicious. As I recall - that was a 4 in. diameter cylinder.

Doc

Early Break of Lab 02 Cylinders ...

2009-10-12T13:39:00.002-07:00

Okay - I just emailed the cylinder data for our `early breaks' of the Sec 02 cylinders. All three breaks were up in the 46k range, which, for a 4-in. dia. cylinder, is putting us in there above 3600 psi. BABY! Plus, the break values were pretty consistent. (Unlike Sec 03 data.)

... test info ...

2009-10-08T09:07:00.000-07:00

Q: ... do we need to calc the cracked section (concrete) properties on the exam?

A: No. But you should still know how to do them.

Q: ... will we have to do a (concrete) mix design on the exam?

A: No.

But everything else we have talked about ... KNOW!

Q: Are there fill-in-the-blank-type questions?

A: Yes.

Q: Are there calcs-type problems?

A: Yes.

... as you study! ...

2009-10-07T15:46:00.000-07:00

1. You probably should have a strength-gain curve (for concrete), or strength gain `info’ somewhere in your notes/notebooks. As I recall, the book has a strength gain curve, but it is pretty tiny. You might google something a bit better (as long as it is correct).
I googled and found this: http://www.ce.memphis.edu/1101/notes/concrete/section_3_properties.html

2. Do not count on me giving you necessary equations, for example, for the Bearing Area Factor. I might give an equation that you will need for the exam, but I also might not.

3. Remember, it is an open book – open notebook exam. (Paper books, paper notebooks only.)

4. And, no, I will not necessarily define terms, and symbols, that I throw at you. That’s what I’m talkin’ about – you need to be able to identify the terms, and symbols.

5. Office hours 9-11 AM, Thu, if you still have questions.

Doc

Upcoming exam ...

2009-10-06T22:20:00.000-07:00

The exam this Friday is `open book, open notebook'. (Paper media only.) Bring your calculators.

Beams DRYING OUT??? ...

2009-10-06T19:24:00.000-07:00

Q: What about our beams drying out (while we let them cure)?

A: Don has been kind enough to go into the lab and `wet' them a bit (and the cylinders).

And this week ...

2009-10-02T21:48:00.000-07:00

We batched our own concrete ... and took slump tests and made test cylinders. Concrete was placed in the forms for our beams. While the concrete cures, we will review, work on previous labs, and take a test.

We also tested air content.

Previously, in Con*Mat ...

2009-10-02T21:46:00.001-07:00

(If you are just joining us ...)

Previously we assembled forms for concrete beams - one will be plain, and the other reinforced. We will mix (batch) our own concrete.

Review ...

2009-10-02T15:14:00.000-07:00

Here is a review: http://serioushunter.com/edu/engr/357/FIRST-REVIEW.pdf

We have covered a lot of stuff.

Doc

SO,

2009-10-02T09:58:00.000-07:00

... even though our materials go non-linear near failure, our service loads are down the in the linear range (via our factors of safety), SO, we can still use I, and E (the stuff we learned in Mech of Mat) to calculate deflections!

BABY!

Due Dates for 2A and 2B ...

2009-09-30T23:41:00.000-07:00

I will be handing back Lab #1 in 342 Recitation tomorrow.

I think you'll want to see my feedback and also the info in the previous post before you turn 2A and 2B in.

Probably what you should do is make any changes you'd like to, and let me see your reports on Friday, for turning in next week.

You may turn in 2A and 2B either as 2 separate reports, or as one, but don't get the two parts blurred if you turn in as one.

Doc

Regarding Reports ...

2009-09-30T23:38:00.001-07:00

Report Format …

Updated ... here

PLUS TWO SLUMP ...

2009-09-28T22:38:00.000-07:00

Good question ...

So, yeah, if I want a " ... PLUS 2 in." slump ... (say 4 in. PLUS 2) ...

Then, options ...

1. Use Table 7.8 with slump = 4 + 2 = 6 in.

2. Use Table 7.8 with slum = 4 in., and then add 10 lb per cu.yd. per in. x 2 in. = (add) 20 lb per cu.yd.

Or, do both and compare.

In either case you will have more water ... and then you will also have more cement (to maintain the w/c ratio).

Probably will give roughly similar answers???

Doc

Slump Test ...

2009-09-28T22:14:00.000-07:00

Some of you I may pull aside and ask to do this test ... so, here:

http://en.wikipedia.org/wiki/Concrete_slump_test

http://www.gatesconcreteforms.com/pdfs/slumpTest.pdf

Doc

Concrete Specs ...

2009-09-27T18:37:00.000-07:00

Concrete Specifications in Design ...

Bring this to class tomorrow ... http://serioushunter.com/edu/engr/357/concrete-specs.pdf

Open-toe shoes ...

2009-09-26T09:56:00.000-07:00

Gang, I do not want to see open-toe shoes in the lab ...

(Despite how beautiful they might be.)

... more example calcs ...

2009-09-23T14:04:00.001-07:00

Example strength calcs for a lab beam ... for your viewing enjoyment.

http://www.associatedcontent.com/article/1320264/strength_of_a_reinforced_concrete_beam.html?cat=15

Example calcs ...

2009-09-23T13:33:00.000-07:00

Okay - for kicks and giggles here are some example beam calcs ...

Deflection calcs, uncracked lab beam:

http://www.associatedcontent.com/article/1570371/deflections_of_an_uncracked_reinforced.html?cat=4

Cracked beam section calcs ...

http://www.associatedcontent.com/article/1570415/cracked_beam_neutral_axis_and_moment.html?cat=4

Internal Stresses Calcs ...

http://www.associatedcontent.com/article/1570451/internal_stresses_in_a_cracked_reinforced.html?cat=4

Effective Moment of Inertia calcs ... YIKES!

http://www.associatedcontent.com/article/1570437/effective_moment_of_inertia_and_deflections.html?cat=4

Rehder / Filler Calc Check ...

2009-09-23T13:16:00.000-07:00

Dang that was fun!

If we tweak the Rehder / Filler calc check just a bit further ... recognizing that if the concrete is linear, then the resultant `C' of the concrete in compression acts 2/3 of the way from the tip (n.a.) across the compression zone ... or 1/3 or 2.01 in. = 0.667 in. from the top of the beam ... then the more precise distance between T and C are ... 5.5 - 0.667 = 4.83 in. ... call it d*.

T = fy As = 40,000 psi x 0.31 in.^2 = 12,400 lb.

M = Td* or Cd* ... = 12,400 lb x 4.83 in. = 59,900 lb-in. (60,000 lb-in.) = 5000 lb-ft.

(I like it when things check!)

BABY! ...

Rebar

2009-09-22T13:23:00.000-07:00

Article on Rebar ...

http://www.associatedcontent.com/article/1349471/rebar.html?singlepage=true&cat=15

In the article there is a link to the CRSI site with even more info, and a video.

http://www.crsi.org/rebar/id.cfm

SHIRT!

2009-09-21T14:30:00.000-07:00

I had the thing made at Shirt Shack here in town (3rd Street ... 882-2203) ... wasn't cheap, but IS FUN! I suppose the template is still on file if you want to get one. If a whole bunch of you want one - maybe we can get a discount! (One of my daughters wants one!)

Doc

Take-Up Device

2009-09-16T16:16:00.000-07:00

Gang, here is an example of the Take-Up-Device (TUD) thing I was talking about in class. I am going to use them along with a manufactured shear wall system for a custom home I am doing the engineering for east of here. Where possible I design `engineered' shear walls, not `manufactured' ones; however, the spaces are so narrow in current application (24 in. wide and 9 ft plus tall walls ... and lots of `window') that I need to climb into the manufactured systems. And since things are so narrow (tight), I really want to eliminate any `looseness' ... alas, the TUDs.

http://www.strongtie.com/ftp/bulletins/T-SWWOOD08/T-SWWOOD08_p09.pdf

Second Lab ... Moist Lumber

2009-09-15T22:51:00.001-07:00

Couple things on the second lab piece ...

It was moist. How moist???

Your handout on adjustment factors for Dim. Lum. also has CM ...

Here is a page I put together dealing with moisture content and spec gravity ...

http://serioushunter.com/edu/engr/357/mc-and-sg.pdf

Outlines for Lab - Wood in Compression

2009-09-14T14:28:00.000-07:00

here are outlines of sorts for our lab tomorrow ... (most of this we discussed in class).

Compression Parallel to Grain: http://serioushunter.com/edu/engr/357/compression-para-lab2a.htm

Compression Perp. to Grain: http://serioushunter.com/edu/engr/357/compression-perp-lab2b.htm

Creep ... wood

2009-09-11T16:16:00.000-07:00

The book also talks about creep in wood members on p. 413. Ughhh ... I don't like the wording. IRL we design against creep at well below the maximum stress levels (I guess depending on how one defines `maximum') ... we design against creep at service load levels. You have all probably seen the effect of creep ... a board or joist or 2x or whatever ... permanently bent, even though it didn't break. And it was probably bent due to loads below the maximum level - but that were there for a long time.

Creep ... Concrete

2009-09-11T16:07:00.000-07:00

Gang, though in the outline, I did not discuss `creep' in our talk today. You need to know what it is - it is basically `plastic' deformation / deflection due to long term load. You can read about it in the book - but the book is more heady (p. 13-14 and 275 for concrete). Plastic meaning permanent (or non-elastic). In concrete members the creep (long term deflection) can be up to 2x the initial deflection (or total being 3x). All the more it leads to deflection problems / challenges in concrete structures ... and is generally mitigated by what is called `compression steel'.

Friday, if I'm here ...

2009-09-09T20:08:00.000-07:00

Outline ... http://serioushunter.com/edu/engr/357/Structural-Concrete.htm

Graphic ... Strength-Gain Curve, below (or, if you like the one on p. 267 of the text???)

Cool sites ...

2009-09-08T21:06:00.000-07:00

I have been snooping around on the web, and have found some cool stuff related to our conversation ...

DOC PS-1 ... this is the product standard for plywood ...
http://ts.nist.gov/Standards/Conformity/upload/PS%201%20final%20complete%20w%20cover.pdf

West Coast Lumber Inspection Bureau ... here are their grading rules for National Grades ...
http://www.wclib.org/R17-PDF-Online/WCLIB/pdfs/e_WCLIB_2004_RulesBook_3.pdf

Doc

Cement and Concrete

2009-09-08T20:17:00.001-07:00

So, I am thinking of starting a conversation on Cement, Concrete ...

http://serioushunter.com/edu/engr/357/Session-7-CementandConcrete.htm

If you are dying for more reading ... Ch. 6 and 7 of the text.

Doc

Metriguard

2009-09-04T15:45:00.000-07:00

A short bike ride west of here, over in lil' ol' Pullman, is a company called Metriguard. They make machinery for testing wood. Maybe we'll do a field trip or something over there - if there is some interest. A buddy of mine works there - he could probably arrange something.

Link is ... http://www.metriguard.com/

Generally I specify visually graded lumber ... on only one or two occasions have I spec'd MSR/MEL ...

Lumber, and ...

2009-09-04T15:39:00.000-07:00

The more I think of it, `Lumber' is a pretty broad term ...

Dimension LUMBER, sawn LUMBER, manufactured LUMBER, laminated veneer LUMBER, laminated strand LUMBER, oriented strand LUMBER (we didn't talk about that one), parallel strand LUMBER (and when you look those up - they are more like TIMBERS).

So, just about any framing member coming from trees (sawn, sawn and glued, peeled and glued, `strands' and glued, whatever), and especially if used as framing members, could be `lumber'.

As opposed, perhaps, to stuff like OSB (oriented strand board).

I'm not too concerned how the names `sort out' - but that you have some understanding of what these different things are.

PSL, LVL, etc.

2009-09-03T21:42:00.001-07:00

Gang, ... here.

This (above link) is to the TrusJoist Specifier's Guide on their LVL, PSL, etc.L stuff. Cool. Definitely print out the first 5 pages.

Doc

Strength Properties ...

2009-09-03T21:14:00.001-07:00

Again I reference (below) the Wood Handbook, Chapter 6 ... it has a lot of good stuff pertinent to our lab.

http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/ch06.pdf

Included is a Load Duration Factor curve.

... tomorrow's talk ... Structural Wood

2009-09-03T20:42:00.000-07:00

Okay, I put together an outline, of sorts, of tomorrow's talk.

You can download it ... here.

I'd like to provide some links to illustrate some of the stuff, but I'm tired.

Doc

Be Clear on this ...

2009-09-02T18:00:00.000-07:00

Okay, I'm drinking a beer and thinking about our conversation in 357 today. Good stuff. When we lay the 4 x 6 flat, our Cfu goes from 1.0 to 1.05. (You can see that in the handout.) What that means is that our unit strength, or design value, increases ... our `psi' value. Our UNIT strength increases by 5%.

BUT, the strength of the member, however, probably decreases.

Let's check ...

The reference resistance or reference capacity, for bending, is M = Fb S ... (it comes from the equation f = M/S and setting f = Fb).

So, (and for the time being NOT showing the other adjustment factors) ...

... for the 4 x 6 on edge ... S = bh^2/6 = 3.5 (5.5)^2/6 = 17.65 in.^3

M = 2540 psi x 17.65 in.^3 = 44,820 lb-in. = 3735 lb-ft.

... for the 4 x 6 on the flat ... S = 5.5 in. (3.5 in.)^2/6 = 11.23 in.^3

M = 2540 psi (1.05) x 11.23 in.^3 = 2667 psi x 11.23 in.^3 = 29,950 lb-in. = 2496 lb-ft.

So,

... by laying the thing flat, the unit strength of the material went up, but the capacity of the member went (way) down.

Oh, BABY! ... I feel a test question coming on.

Lab 1 Report Contents

2009-09-02T16:21:00.000-07:00

Okay ... I elaborated a bit on what I want to see in a lab report ... (elaborated from the previously posted outline) ...

HERE

8. Report Contents

1) Intro
2) Background
3) Lab setup
4) Predicted Performance (calcs)

(Based on `adjusted reference strength values' we saw how to calc in class.)

P to break the beam in bending
P to break the beam in shear
P to crush wood in bearing (bearing perp to grain)
And thus `which governs’?
Beam Stiffness, k = P/Δ

5) Actual Performance

Plot of P vs. Δ
Observed k vs. calculated
Nature of failure

Also: calculate the stress `f' at which we had `failure' ... and compare to the corresponding `adjusted reference strength value'.

If you did this correctly, you should be able to check, since the ratio of predicted P / P at observed failure ... should = ... ratio of adjusted reference strength /calc'd stress at failure.

6) Discussion
7) References
8) Appendix/Appendices

Bring your work to Lab on Tuesday and we'll work on this during lab time ...

And maybe break some more stuff.

CL ...

2009-09-02T16:12:00.000-07:00

I just calc'd the CL for the 4 x 6 on edge for our situation.

It is 0.996.

Close to unity. We could say that the beam is only `very slightly unstable' as loaded.

For your report you can reference me on this blog for CL.

Bearing Area Factor

2009-09-02T15:56:00.000-07:00

Here is the Bearing Area Factor ... (link is here).

This equation gets real `interesting' when the bearing length is a `knife-edge'. Might want to discuss this as applied to the support conditions.

Doc

Adjustment Factors ...

2009-09-02T15:48:00.001-07:00

Here are the Adjustment Factors applicable to our lab situation ...

Fb’ = Fb CD CM Ct CL CF Cfu Ci Cr

Fv’ = Fv CD CM Ct Ci

Fcperp’ = Fcperp CM Ct Ci Cb

Fc’ = Fc CD CM Ct CF Ci CP

...

For the 4 x 6 laid flat, CL = 1.0.

I will need to calc the CL for the 4 x 6 on edge (stand by).

CP is for compressive load, which we haven't talked as much about yet.

Cb ... Bearing Area Factor ... I'll put up on another post.

(Sorry, I'm not sure how to do subscripts on this blog.)

Load Duration Factor

2009-09-01T23:04:00.000-07:00

... borrowed from the WSU Timber site, here:

http://timber.ce.wsu.edu/Supplements/LoadDuration/Default.htm

Browsers ...

2009-08-31T21:16:00.000-07:00

Gang, for reasons I don't understand, the Outline for the first lab, when I pull it up in IE 8, is all strange. However, when I view it with Mozilla Firefox, or Seamonkey, it's fine ... so, either use one of the other browsers, or pull it off IE 8 and just delete all that formatting stuff.

http://www.serioushunter.com/edu/engr/357/Lab-1.htm

Doc

Lab Groups ...

2009-08-31T13:36:00.000-07:00

So, as indicated in the syllabus, and in class, I want you working in groups of 3 to 5 people. Five is better because you can better spread out the work, and I and my grader have less to grade.

Consider the following (roles):

1. Group LEADER
2. Note-taker
3. Photographer
4. Operator (e.g., pumps the hydraulic jack)
5. Measurer (reads gages, dials, etc.)

You might see what the book (or web) has to say about: 1) Load Cells, and 2) Dial Gages ... prior to lab tomorrow.

Doc

Connection Hardware - Metal Side Plates

2009-08-30T18:11:00.001-07:00

Okay, here is a link to some metal side plate connection hardware ... note the max distance across grain between bolts (3 in.). My sketches in class make sense to me - but in case some of you were sitting there going ... "Huh????" ... here:

http://www.strongtie.com/products/connectors/cc-ecc-eccu.asp

For some of the hardware it looks like, strictly speaking, the distance from the top bolt to the bearing is more than 5 in. ... but, strictly speaking, the NDS requires 5 in. max between outermost rows of bolts, not nec. down to the bearing plate.

Course Index - 357

2009-08-30T16:09:00.000-07:00

Amazing ... I have put together a course index for CE 357, have started a schedule, and the schedule has some links to stuff we have talked about and WILL. You can download an outline for tomorrow's talk, plus an outline for a lab - where we'll bust some wood.

here: http://www.serioushunter.com/edu/engr/357/

Adjustment Factors for Wood

2009-08-29T23:01:00.000-07:00

On Monday we will be talking about `Adjustment Factors' in wood design. I'll post an outline later, but for now - here are some links:

NDS Commentary on Adjustment Factors ... here

Load duration factor blurb ... here.

The Wood Handbook ...

2009-08-27T16:52:00.000-07:00

Gang, the authoritative source of information on wood (as a structural material) is The Wood Handbook. I have provided a link to a downloadable .pdf version ... here.

There is so much I could say at this juncture, but, for now, won't.

... wood!

2009-08-27T16:49:00.000-07:00

... tomorrow we will start talking even more about wood. Our conversation will launch from the linked outline of `Design Values - Wood' ( ... here).

Deflections ... and Stiffness calcs

2009-08-26T15:34:00.000-07:00

In the previous post I calc'd the stiffness of 4 x 4 beam ... 19,230 lb/in. This value should be good for the `linear' range. As mentioned in class, as we near `failure', our materials, and members, start to `depart from linear'. Thus the `k' would no longer relate P and delta ... and nor do our PL^3/48EI and other equations work.

So, why teach these equations in school?

The reason we teach them in school - is because we still use them in real life (at least in a lot of applications) ... because our factors of safety (on order of 2 or more) demand that we are using our buildings and structural members at levels (still) down in the linear range.

Deflections are calculated at WORKING or SERVICE load levels, not failure load levels. (I feel a test question coming on.)

BABY!

... member stiffness, k

2009-08-26T15:31:00.000-07:00

Okay, so, for our example calcs, we could say that the 4 x 4 has an expected stiffness of ...

k = P / delta = 1000 lb/0.052 in. = 19,230 lb/in.

(This value is dependent on the L = 3 ft, load at mid-span, 4 x 4 nominal dimensions, etc. A 6 x 6 of the same material, same span, etc., would have a different stiffness.)

Syllabus, in Blog form ...

2009-08-24T20:18:00.000-07:00

CE 357 – PROPERTIES OF CONSTRUCTION MATERIALS - FALL 2009

M,W, F: TLC 223 11:30 am - 12:20 pm Sections 02,03
TUE: BEL 116 11:30 am - 01:20 pm Section 02
BEL 116 02:30 pm - 04:20 pm Section 03

PROF: Jeff R. Filler, Ph.D., P.E. (Consulting Engineer)
PROF INFO: http://woodengineering.com/Filler-CV-8-2009.pdf
OFFICE: BEL 103 (Tentative)
OFFICE HOURS: (TBA)
PROF CONTACT INFO: (TBA)

COURSE DESCRIPTION (BRIEF): course will cover the use and testing of common materials used in engineered construction including wood, cement/concrete, steel, etc. Course includes a lab where students will be able to `test’ materials, obtain and interpret data, and write lab reports.

GRADING (Proposed): 40% Three Exams
60% Lab Reports

Prerequisites: CE 215, ENGR 350

TOOLS NEEDED: hand held calculator with basic trigonometric functions (sine, cosine, square root, etc.). Access to a personal computer with Excel or similar spreadsheet software.

OTHER: students must have a working email address and access to the Internet.

All lab reports must be `group effort’. Groups shall consist of 3 to 5 students. Individual reports/papers will not be accepted for lab assignments.

TEXT: Materials for Civil and Construction Engineers, Mamlouk & Zaniewski, available at Bookstore.

COURSE WEBSITE: go to: … CE357.blogspot.com

Getting started items to review ...

2009-08-24T20:17:00.001-07:00

List of things for you to review to get started …

1. Strength
2. Stress
3. Strain
4. Stiffness (of a Material)
5. Stiffness (of a Structural Member)
6. Elastic
7. Plastic
8. Linear (Linear Elastic)
9. Section Modulus, S
10. Elastic Modulus, E
11. Area Moment of Inertia, I
12. Stress-Strain Curve

Blow the dust off your Mech of Mat book ... you will be using it.