Thaddeus in NYC!

The legendary ARE Structural Systems tutor David Thaddeus is coming to NYC next week (5-7 June)!

The three-day, 30-hour intensive course will take place at Perkins Eastman’s office, near Union Square. (I can’t find how much it will cost though…)

I actually don’t know anyone who took the course myself – but words are if you schedule your test 2 weeks or so after you take that class, you have a very high chance of passing. Check it out:

https://david-thaddeus.squarespace.com/calendar

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SS Vignette

Since I am not supposed to disclose any contents of the exam, all I can do is to draw your attention to one point that I was (still am) very confused about, something that almost threw me off entirely.

In the sample SS vignette on NCARB’s official guide, instruction #11 says “The structure must accommodate a clerestory window to be located along the FULL LENGTH of the north wall of the common area”. In the sample passing solution, there are two columns in that north wall, hence, according to my understanding, violating the FULL LENGTH requirement.

People on the forum suggest that instruction #4, which says “Columns may be located within walls, including the window wall and the clerestory window wall.” means it’s ok to put columns in the middle of the wall. My interpretation is that you can put columns at the ends of the wall, not in the middle of it; it just sounds like two conflicting requirements to ask for “full length accommodation” yet allowing columns in it.

Anyway, all I am saying is that I was not aware of this before going into the exam and it took me a long time to decide whether to put columns in the middle of the wall or make the beam span longer than it’s supposed to- more than 40′, which almost cost me the whole test.

ss vignette

ncarb sample vignette program

ss vignette 2

ncarb sample vignette passing solution- upper level

 

That said…. (I can’t believe) I passed!!! Other than this hiccup in the vignette everything was pretty reasonable, not too many curve balls and WTF questions. I am working on “visualizing ARE 4.0” diagram #3, hopefully can share it soon.

Retaking CDS next month… last one!! Almost, almost there!!!

 

 

Back from Italy!

After retaking SS on 23rd June, I went on a short trip to Italy, as a little reward for myself for all the studies I’ve done so far. I saw two buildings from Kaplan’s “notable buildings”… The Pantheon and Palazzetto Dello Sport. Pantheon I planned to see (duh), but Palazzetto Dello Sport I just randomly came across on my way to Zaha Hadid’s MAXXI. What a pleasant surprise! It was a humble, quiet gem in a less busy area of Rome. If you are going to Rome, make sure you don’t miss it!

Sure I learned about them in “architecture 101”, but seeing these beautiful structures after taking the exam help me appreciate them even more.

pantheon

pantheon

palazzetto dello sport

palazzetto dello sport

(re)Starting with Flash Cards (SS)

Coming back from a two-week vacation in Hong Kong, it’s time to get back to study mode again. This is also about exactly one year since I took my first test, so maybe it’s a good time for a recap. For your reference, I did:

April 2013 – SD – pass
June 2013 – SS – fail
June 2013 – PPP – pass
Sept 2013 – BS – pass
Oct 2013 – SPD – pass

Nov 2013 – CDS – fail
Mar 2014 – BDCS – pass

In a nutshell, I passed 5 out of 7 tests in a year’s time, which I am pretty happy about. Looking back it might not have been the best testing order, but I was thrown off by the July-August blackout last year so it was different.

When I was studying for my BDCS exam, I realized it is extremely helpful to start with flash cards. I guess being familiar with the terminologies makes all the readings much easier. I also pin as much as I can on pinterest  cuz a lot of times pictures are better than words. As I prepare for my re-match with Structural Systems (SS), I plan to do exactly the same.

Kaplan Flash Cards

Kaplan Flash Cards

Difference between Malleability and Ductility

“The difference between malleability and ductility is that malleability is the ability to deform easily upon the application of a compressive force, and ductility is doing the same with tensile force.

*Ductility is a mechanical property used to describe the extent to which materials can be deformed plastically without fracture.

In material science, ductility specifically refers to a material’s ability to deform under tensile stress; this is often characterized by the material’s ability to be stretched into a wire.

Malleability, a similar concept, refers to a material’s ability to deform under compressive stress; this is often characterized by the material’s ability to form a thin sheet by hammering or rolling. Ductility and malleability do not always correlate with each other; for instance, gold is both ductile and malleable, but lead is only malleable. ”

Source: http://answers.yahoo.com/question/index?qid=20090303051823AAFRJmT

Difference between Laitance & Efflorescence

Laitance and efflorescence are really two completely different things, but they are both white, powdery substances, which can be confusing.

In short, laitance is formed when there’s too much water in the concrete mix, while efflorescence is the deposit on masonry surfaces caused by soluble salts in the units or in the mortar.

Laitance can be avoided by controlling the amount of water in the concrete mix. Efflorescence can be prevented, or at least minimized, by selecting materials free of harmful salts and by preventing water from penetrating the masonry. This may be accomplished by the use of solid and tight mortar joints, capped walls, effective flashing, and adequate weather protection of the masonry during construction.

Both laitance and efflorescence can present both cosmetic AND structural problems.

read more:
http://en.wikipedia.org/wiki/Efflorescence
http://www.concreteconstruction.net/concrete-articles/meaning-of-laitance.aspx

 

 

List of Sizes, Spans, Spacings, and Ratios (SS)

[WOOD]
– Wood joists: 2×8, 2×10, 2×12 spaced 12, 14 or 16 inches apart
– Maximum slenderness ratio for column (l/r) is 50

[STEEL]
– Deflection limit for steel members= L/360 for live load only
– General steel beam depth= 1/22 x span
– Depth to span ratio of joists is limited to 1/24
– For composite beam to be efficient= slab thickness of 4 to 5 1/2 inches
– Preferable maximum allowed radius of gyration(Kl/r) = 200

[CONCRETE]
– Code specifies width b of T beam may not exceed 1/4 of span
– For T beam, in general d should be about 1.5 times b
– Net strain reinforcement must be greater than or equal to 0.004
– For Tensile reinforcements, code requires a maximum spacing between bars on the main reinforcement for bending to be 3 times slab thickness or 18 inches, whichever is smaller
– For compressive reinforcements, ties must be at least #3 in size, at spacing less than 16 times the diameter of the longitudinal bars or 48 times the diameter of the tie bars
– Minimum size of spiral reinforcement is 3/8 inch
– Clear spacing between spirals must be between 1 to 3 inches
– Reinforcing bars with strengths of 40, 60 and 75psi are common

[STUD WALLS]
– Common 2×4 studs places 16 inches on center

[REINFORCED BRICK MASONRY]
– Bar spacing about 18 to 36 inches

[SYSTEMS]
– Wind tunnel test: for buildings with height to width ratio > 5:1, or taller than 400′
– Staggered truss is good for buildings at least 8-10 stories tall, with spans larger than 45′
– Optimum depth to span ratio for truss is 1:10
– Span to depth ratio for diaphragms: 4:1
– For wind force, drift should be limited to 1/500 of building’s height, and drift between adjacent stories should be limited to 0.0025 times story height
– Removal and compaction of fill for foundation is usually economical up to 6 feet
– Base isolation is most effective for buildings 4 stories tall
– Depth of 2 way systems varies between 1/12 to 1/20 of span
– Cable structure: economical up to 150 feet