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Maybe it was not built this way. Would need to check with photographs.
Looking for where the missing negative steel reinforcement would have been is interesting.
Hard to tell.
In the second level terrace balcony the concrete joists extend from west parapet uninterrupted to east parapet. There are 4-3/4" dia. rods in each beam - 2 at the top and 2 at the bottom. They are hooked on each end and embedded into the parapet.
The concrete joists on the main level don't seem to have anything like that. There could have and maybe should have been continuous steel rods from west to east bent into a "smile" - low in the center bending up to high on the east and west ends.
Maybe that's part of what is missing.
but the shower in EJ's room has plate glass set on plaster for the walls and the floor.
In one drawing the cork is continuous around the shower stall and glass is set upon that.
In terms of the furniture and casework
- the drawings really bring out as some of the Flickr shots confirm all the wooden rounded edges.
Curves are a huge part of this work.
The door edges are even curved - bullnosed in section.
No hinges - only pins top and bottom.
Because flitches (consecutive slices) of veneer depend for their width upon the diameter (or more precisely, upon the chord) of the tree trunk which yields the flitch, and more so when the narrow bands of light-colored sapwood under the bark of the tree is to be included, and because no two trees are alike, Wright could not expect to maintain a predetermined vertical design unit where these veneered panels were concerned. Thus, varying widths of these horizontal bands of walnut can be detected, from one place to another, in the house and guest house . . .
Pretty much, Tom. Silman notes the plans do not indicate the critical missing reinforcement. He also makes the point this actually prevented the large, long beams from being calculated accurately as a true cantilevers. This puzzled him as this calculation was well known in 1935, and since the common claim to fame of FW is being cantilevered over a waterfall. The investigation found the fatal cracking occurring at the beam bolsters, and as the building weight/bending moment increased over time, and possibly only the additional steel that was added prevented a catastrophe from happening sooner. Upon hearing the initial results, Glickman exclaimed something in the order of "OMG, I forgot the negative reinforcement!". That's the simple answer to the whole thing, and FLLW never deserved any bad press as far as his design being flawed; assuming the engineering had been done properly.Tom wrote: ↑Thu Jun 18, 2020 12:37 pmThe concrete joists on the main level don't seem to have anything like that. There could have and maybe should have been continuous steel rods from west to east bent into a "smile" - low in the center bending up to high on the east and west ends.
Maybe that's part of what is missing.
The additional steel being added issue is interesting. I'm not aware of any mention to Kaufman from his engineers, upon their review of the plans, that the most important calculation and requirement for the building's integrity was missing. The record only reports that "more steel" was needed. Any additional steel would have been pointless, as turned out to be the case, unless the component of engineering for the cantilever was considered. Wright protested, and as far as he was concerned things went ahead as planned. It's possible his faith in Wes and Glickman was valid enough to be so vehement-if they convinced him the engineering was thorough. Unfortunately, it was not. It's almost unbelievable Kaufman's engineers would not find the calculation missing and detail its importance to him. Perhaps they did, and if so, it certainly did not make it back to Wright's engineers. Regardless, it would still put tremendous blame on them for incorrectly addressing the problem, whether or not they actually did discover it...
Can someone correctly explain "negative reinforcement" in terms a high-schooler could understand ? I've never managed to absorb it.
Engineers balance forces in their calculations for buildings to stand up.
The typical and most basic calculation involves an equation in which both sides of the equation must be made to cancel each other out in order to equal zero or static equilibrium.
So if you have a force bearing down you must have an equal and opposite force bearing up to balance (Isaacs 2nd law).
Call the downward force positive. Then you must have an upward, or negative force, to balance.
Those positive and negative forces are translated into the equations and work just like numbers: +a-a=0.
I mean if you leave out the negative reinforcement it's kinda like leaving out THE reinforcement.
It is not a peripheral oversight.
Maybe I'm interpreting this all wrong. But will have to stand until a better explaination appears here.
Take the droop of the main level balcony. It droops on either end like a frown.
That is it's positive bending. It's the shape of the forces. Some call it the positive bending moment.
That frown needs to be negatively reinforced directly. Negative reinforcement would be shaped the oppoiste of a frown.
From what I can tell from the scant structural drawings in the file, it was not addressed. There is steel in the concrete beams and joists, and they do hold things together, but there is no continual reinforcement E/W across that cantilever in the opposite direction of the forces that shape the droop.
One day at the entrance to the Hillside Draughting Room, Wes and I were chatting about something or other ... when he suddenly lit into Mr.Wright's structural understanding of "wood". He didn't go into much detail, but I was absolutely taken aback: totally surprised at how vehement he was, considering that the incident must have occurred twenty-five or thirty years or more before that day. Anyone who knew Wes understood how worked up he could get about things ... but then ... a second later ... his mind would shift to something else, entirely, and he would be off and running on a problem far more important.
Evidently Mr. Wright had been trying to reduce costs, as Wes said he was working on a design for a house that would use only one stock wood item for every part of the house ... floors, walls, roof: everything. Not wanting to egg Wes on ... I let it go, but I've often wondered if the house in question might have been the 1940 Franklin Watkins Studio for Barnegat City, New Jersey, except that design included several heavy concrete forms, designed to lift and support the wood structure off its low, sandy, ocean-side site.
I am reminded of my cabinet-shop foreman, an artist, not an engineer, who tried to tell me that "moment"---as in bending moment---was a temporal matter . . . literally, a moment in time of some sort. I changed the subject . . .
Here's a start; unfortunately the writer forgets to tell us what negative reinforcement is---but his diagram might be useful.
https://www.quora.com/What-do-you-mean- ... ent-design
Rood: I could see Wes referring to a single wood section being used throughout, for the non-masonry elements in the construction. Watkins would be a candidate. In Schindler, it would be the Log House he designed in 1916-17 . . .?
I may be wrong but I don't think so.
...bending moment is simply the shape the beam takes under a certain load.
If the beam is loaded with a force A it has a certain shape.
If it's loaded with a force B it has another shape.
Two different "moments"
I took one year of structures - I was a B student.
I forgot about the positive reinforcement!
Went through those links you provided.
I had forgotten about positive and negative forces existing in a beam at the same time although typically in distinct areas.
For a simple beam he shows the reinforcement low in the middle and high on the sides.
Which would mean for the main level balcony at FW it would need to be high in the middle and low on the sides - the opposite of what I was saying.
and that really does confuse me.
Wish someone who knows what they're talking about was with us here.
P.S. I want to understand this so I'm not giving up.
So if the main level balcony terrace at FW bends into a frown, and it does, then steel needs to be toward the top of those joists all the way across and not bent into a smile.