What Architects Do

Precast Concrete

Precast concrete is a sustainable building system that provides slender, efficient structural elements.  Precast plants provide many advantages over concrete cast in the field.  Better control over conditions, materials, and workmanship gives a higher strength, higher quality product in a safer environment.  Repetitive forms can be reused.  The limitations of transportation, however, means widths over 14' can be problematic and expensive to move.


Testing is similar to that of site-cast concrete.

Precast concrete is often pre-stressed - prestressing allows a much more efficient distribution of compressive and tensile forces, thus it allows for smaller, cheaper concrete members.  Tensioned steel squeezes the concrete, putting the entire concrete section under compression, reducing cracking.  The strands can be shaped to more closely match the path of tensile forces through the beam, which tends to be at the top near the ends, but at the bottom near the center of the span.  T








Prestressing comes in two flavors:


PRE-TENSIONED:

Manufactured with steel cables or bars, called “tendons,” are pulled taut prior to the casting of the concrete, which bonds to the tendons and the force is transferred along the surface area of the rebar.  This site goes slightly further in depth.

POST-TENSIONED:
The tendons are not allowed to bond during curing by sheathing them.  After the concrete has cured, the tendons are jacked taut and anchored to the ends of the concrete, pulling the concrete section into compression.  Most commonly used in large building projects such as high-rises and bridges. Post-tensioned concrete slabs-on-grade also can be found where there are unusual soil conditions.

Precast pieces were used to reinforce the stage floor prior to Kirstie Alley's appearance on Dancing With The Stars.

Anger Management #2: Pass/Fail Letters

The ARE process makes me want to start fires. Nothing huge, just a small toilet paper fire in the bathroom of the testing center. But that would only hurt the maintenance staff of the office building involved, and that’s not who an ARE candidate should direct rage toward. These rants are an outlet to prevent any harm coming to you, Prometric-tenant building maintenance workers. You’re welcome.

I know you must grade a lot of exams. I mean there were around thirty from my school’s alums alone last year! Whew! So I guess we’re lucky to get any feedback at all. Positive feedback is a waste of space, so that is not given, ergo being given no information equals a shiny gold star – you got it, dude! But failure prompts a little more info, so we can correct what we did. Emphasis on “a little” more. Yes, you FAILED MISERABLY on the stair vignette. Everything else was fine except SOMETHING ON THE STAIR. We’re not going to tell you what, as you certainly remember everything you did on that particular drawing – you know what you did, dumbass. You now get to slowly lose your mind as OMIGOD DID I DRAW THE STAIRS UPSIDE DOWN? DID I END THEM 6 FEET ABOVE THE FLOOR I CAN’T REMEMBER! GAAAH! Maybe you emptied out that gutter right over a door way, maybe you didn’t… there’s no proof you didn’t, and thus, no proof that you are not a retard. So suck on that for six months, and try harder next time. Good job on everything else though! Except that thing. You know.

Masonry Mortar

Don't mistake wine for mortar; however, both depend on quality of ingredients

Mortar can be similar to wine in that you should be aware of the labels because each type is different. Similar to wine, Mortar is created by several different ingredients making some mortar stronger than others. There's suitable mortar for colder climates and there's a variety of colors to choose from. I am not encouraging the use of wine on job sites, btw. This is just to help you remember the differences in mortar types.

Mortar is made up of portland cement, hydrated lime, and sand (aggregate) & water.

Lime is added to impart smoothness and workability. Its produced by burning limestone or shells in a kiln to drive off carbon dioxide and leave quicklime (calcium oxide).

Hydrated Lime (slaked lime): released large quantities of heat.

Mortar mix can be obtained in shades ranging from pure white to pure black; makes up 20% of exposed surface area of brick wall, therefore color is important.

Mortar composition standard for unit masonry refer to: ASTM C270

TYPE N: used for most purposes

TYPE M & S: higher strength structural walls (or for severe weather). S is used below grade, as well.

TYPE O: most economical and used for non-bearing walls

For more information on selecting the right mortar for your job refer to Masonry Contractors Association of America

Movie Building Inspector #1

It's time for episode 1 of Movie Building Inspector, where today we are responding to reports of violations at a certain school for wizards and witches... I hear it's one of those liberal ones over in Europe.  Let's just take a look in the main hall and GAAAH!

Hogwart's Dining Room

Holy crap, Hogwart's is a fire hazard if I have ever seen one!

Sure, heavy timber construction is better than light frame, but lets back those 5,000 open flames away from the roof structure, unless you have an anti-litigation spell for all those angry parents of flattened children - class action suiticus dismissum! The more resistant the structure is to heat, the bigger the building can be! Also, should Hogwarts have a proper sprinkler system (which they do, although the fairies-with-tiny-buckets-of-water system is only approved for use in England), the structure could be enlarged and travel distances to exits lengthened. See the chart below for Construction Types.

Click to enlarge

Who isn't a fan of magic stairs that swing from corridor to corridor? Of course, this design would get an immediate stamp of rejection from the DOB...

Stairs to Gryffindor Hall

If you want to bring these up to code, here's a few design rules you should know:

• Handrails at the bottom of stairs shall extend 12" plus extend the slope for a horizontal distance the depth of one more tread. 
• Vertical distance between landings may not exceed 12'-0" with headroom clearance no less than 6'-8".
• Monumental Stairs are stairs 88" in width or wider and require intermediate handrail.
• Avoid single steps; where there are more than three steps, handrails must be provided.
• Handrails must be located 34"-38" above nose of stair or ramp.
• Width of an egress stair is based on occupancy: in most cases, 44" is the minimum but you can go to 36" in a residential occupancy.
• American Disabilities Act requires the below dimensions for handrail design:

You should always refer to your local building code for regulations regarding stair design, as they may have added a few requirements of their own.

Rainwater Collection

My last year in school, I was a member of a studio that designed and helped construct a 1200 SF home for a Central Texas ranch manager and his wife.  We used as many green materials and technologies as we could, as the ranch's goal was not cattle-raising, but environmental preservation.  The centerpiece was a rainwater collection system that gave the house a self-sufficient water supply that did not further strain the drying aquifers of what was then a baby drought.  Flash forward 7 years and the drought has not relented, however, the house continues to maximize the little rainfall it receives and provide plenty for the house's owners.  The manager elaborates on the system in his journal here and gives a good break down of the basic functions.  As the AREs look more and more like the LEED exam, particularly the SPD exam, it's all good stuff to know.

The NY Times is down with Steel Connections

The New York Times has a great series of photos showing steelworkers, and inadvertently, connection details of the Freedom Tower (1,776 feet, baby!)  Click through the gallery here. 

Iron worker on the Freedom Tower, credit NYTimes.com.

Shear studs are used to connect beams to the concrete floor structure, effectively bonding the two.  The floor structure then becomes the top flange of the beam, increasing its capacity to resist bending.  This composite beam action is very efficient because it doubles up on usage of the concrete slab's strength.  This allows heavier  loads and longer spans.  Walking on shear studs 75 stories in the air also causes you to become a certified bad-ass, even if you are hooked up to proper safety equipment.

That gusset plate is pretty cool.  What's it gonna do?  You can see the continuous fillet weld connecting it to the top flange of the beam - that bad boy was probably shop welded, as that would be an intense weld to perform in its current place.  As many welds as possible should be done in the shop rather than the field - it's cheaper, easier, and the results are better.  Pre-formed holes indicate it's gonna get bolts.  I assume a diagonal beam will be bolted at an angle perpendicular to the right face of the plate, and a big connector clip will cover all the bolt holes and connect it to the gusset plate.

Flip through the gallery and look for other cool stuff.  If this don't jazz you up, more than you already are for football season, I don't know what will.

In conclusion, STEEL! WOOOO!