Publication Pidgin Fall 2007 Text

7/31/2019 Publication Pidgin Fall 2007 Text

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Its J st a FacadeMarc SimmonsAs told to Brian Tabolt

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I wanted to talk with you about your offices work with OMA on the Prada

Beverly Hills Epicenter because it is a really good illustration of Fronts

approach. The end result looks incredibly simple; but is actually quite

complicated to achieve. It is an instance where the clarity of the diagram

really rests on a detailand this crucial detail is actually a lack of detail,

a moment where the tectonic isnt really expressed. When I first saw the

facade, I thought what can there possibly be to talk about here? but it is

exactly that restraint which makes the solution so successful - and there

IS an incredible story behind how the team got to that point. If this project

had been constructed with more conventional building techniques, it

would probably look much more techy. But here, incredible technology

and effort were exerted to make the engineering disappear. So I would

love to hear how you and your office worked with the project team to help

retain the clarity of OMAs original diagram.

Well, as you can see, the pure concept is this 14 x 42 oot sheet o aluminum.The box is conceived o as a pure prism oating in space, with a void in

the middle. That opening is then dematerialized by the perimeter PDLC

(Polymer-Dispersed Liquid Crystal) screens. Within the void are two

staircases, symmetrical around the void centerline rising simultaneously

rom the ront and the rear o the store.

Its a brilliant idea. In OMAs shopping analysis a key concept is to maximize

a consumers experience o and exposure to display -- this being achieved by

generating universally interesting but di erentiated circulation relative to

the amount o sur ace area in the store. By introducing this reverse staircase

you can modi y what is ront and what is back. A shopper comes in, and as

they circulate around back, they are re-oriented towards the middle. You

circulate the other way, and you realize the back is somehow equal. Its not

like the Apple store here in New York City where you go up and you have to

double back. This is a loop. As you rise, the PDLC screens yield at the middle

allowing you to to choose le t or right, entering into an e ective gure 8


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that you couldnt achieve that e ect at that larger scale. The acade as a

single pixel becomes and index or abrication and logistical limits.

Once you understand that there is a possibility o success and there is a

commitment to the concept, then everyone is prepared, in a sense, to ail-- a

recognition by the owner o a chance o ailure by the design/contracting

team is key-- it is a pre-condition or taking the risk. Simply because this

hasnt been done be ore, and you dont know that it can be done at all. You

certainly dont know that it can be done within a budget, or within a time

rame that meets the project requirements. But i you suspend your disbelie

a or a little while and you look at the scale, look at the size, you think...well,

we can truck that. Its difcult - you probably have to do it on an angle, and

14 is kind o a limit. So you know you can truck it. You can probably handle

it, you can probably install it, so the rst question becomes can you make

it? Thats probably the most important thing or us. The other question iso course can you hoist it on Rodeo Drive over the weekend or whatever...so

there are Beverly Hills issues involved.

The cast o characters was OMA, Brand + Allen Architects, Prada and their

own design/construction team led by Marco Lenardon, and BCC Project

Managers led by Chris Beetha. The Brand + Allen team was Nicole Long and

Ingrid Schoenlank. The main people rom OMA apart rom Rem Koolhaas

were Ole Scheeren, Jessica Rothschild - she had a lot to do with it - Amale

Andraos, Hilary Sample and Eric Chang who executed the back end o the

project. You have Plant Construction, the construction management rm

who is looking a ter the construction or the whole building. Plant was led

by Elliott Grimshaw and Je Gherardini who did an amazing job making

everything happen. They were very committed to making it work. And then

one o the better metal abricators in the area, CS Erectors Inc, was brought

on board. They initially looked at the project, be ore Front even got involved,

and saw it at a conceptual level and they werent really interested in pursuing

it.

shopping space. Once again the circulation loops are equal. The conceptual

interior o this oor is the sponge material developed by OMA and lining all

interior walls. The staircase up to the next level is concealed within a wall

cavity, ensuring that the purity o the second oor space is uninterrupted.

The exterior o the prism is all aluminum. The top is an aluminum oor,

the soft is an aluminum ceiling. There is an aluminum ascia capturing

the PDLC screens. And o course, the acade is aluminum where it projects

beyond the portal rame to the exterior, both on the Rodeo Drive aade and

on the rear alley-way aade. So you can make it look like the building is two

portal rames with the box suspended rom it; which is partly the case.

So the concept o the acade is really important to the reading o the whole

building, and thats why OMA and Brand + Allen (Executive Architects) were

so ocused on making that piece one, and making the joint go away.

Its a game o abstraction. Why this is conceptually an aluminum

prism, youd have to ask Rem-- but i the joint were articulated, it would

undoubtedly change the magic. I the panel on the ront were divided into

multiples, it would change the single-pixel abstraction into something that

becomes less about raw texture and material and into something more

about pattern.

First, what you have to understand is that the conceptual logic has to be

strong enough to convince someone to even want to do this. Because the

path o least resistance will prevail in the absence o that clarity. Thats the

precondition or even making this happen. And whats interesting about

OMA as an ofce is that they have that conceptual clarity. We all recognized

that the building exists at a precise scale, that the diagram is actually

achievable - meaning that 42 eet might be achievable in a single panel.

I the building was 60 eet wide instead o about 45 eet, you probably

wouldnt propose this. Nobody knew this ahead o time, o course, but it

would have become clear


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It wasnt their job to solve

it rom scratch-- they werent going to

be hired on a kind o design-build basis until the

design team had a more evolved strategy.

So we became involved around the beginning o design

development. We said, OK, the contractors are saying no, but everyone

is still interested in the idea so lets just try to engineer something-- a

plausible strategy. The rst decision was that we werent going to use the

panels as any part o the weather enclosure system - only as a rain-screen.

We were going to need per orated metal panel on the top, and broken-

down metal panels on the soft, which have lighting and other things in

them, so the conceptual diagram o a pure prism is already compromised

there. The per orated metal on the roo is to let water drain, so we havea complete insulated and water-proo drained roo system underneath.

The sides and ront are conceptually solid, but we have waterproo ng and

insulation on all sides o the exposed box rst. The verticals are designed as

conventional wall systems, the roo is designed as a roo system, and the

soft is designed as a vapor-impermeable sur ace that doesnt have to take

direct rain. So all the sur aces in reality are slightly di erent.

O course when you start hanging ve di erent sur aces o metal, you have

to make all necessary structural penetrations through the waterproo ng

substrates. At the top there are a series o metal stando s that penetrate

through rom the structure. The waterproo ng is then built up around

them and drainedaway. There are then

a series o horizontal rails

that are set up on the roo , riding

above the waterproo ng layer. The

per orated panels are then set on top o that,

and they all have a concealed locking mechanism and

each one is individually hinged. So you can get up there and

open them up to service the cleanouts and the drains. So when you

are standing up on the third oor retail space, and you are looking through

that ull height glass wall, you are looking at a plane o metal plates on the

oor, with a seamless recessed glass panel, which then goes out smooth

and ush onto this per orated metal sur ace. Obliquely, it actually does

look like a continuous sur ace, so you have to achieve that e ect at the

top o the prism while making a roo system that is ully accessible,

maintainable, and drained.

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The vertical walls are easy in a way. The ront o the Schaulager Museum in

Basel by Herzog & de Meuron is a huge welded up steel plate acade with

a olded geometry. That baby must have been built in a similar way. The

sel -weight is taken out at two points near the corners, and are actually

slipped horizontally. There are a series o additional wind-load restraints tied

in all the way along the panel at the top, which are really more like tension

rods that you can dial in and out. You can adjust them once the panel is in.

But the idea is that the panel has to hang at the top and be restrained rom

wind pressures by a line o lateral ties running continuously across the top

and bottom with sti eners connecting them to make sure the panel can

span. But at the same time, the panel has to be able to breathe thermally.

Its taking on a huge amount o heat, and expanding sideways. So that is

why all the wind-load restraints have to be slipped horizontally, to allow the

panel to move about a 1/4 inch in each direction over 42 eet.

The next thing you ask is, what is a reasonable material thickness? Youcould decide to engineer the panel to be 1/8 inch thick, and put sti ener

rames on it up the whazoo, so the sti ener rame would be doing all the

work. But, obviously you couldnt handle or abricate a sheet o aluminum

that big while being that thin-- it would likely crumple and and pillow losing

all sense o atness. The next challenge is size-- you cant buy a sheet o

aluminum this large, so you have to hot-roll it custom - no cold ormed

coil options here. We talked to the guys at Alcoa or a recommendation

on which kind o alloy is suitable or corrosion resistance and hot-rolled

applications, and it turns out there is only one. They recommended hot

rolling it to about an inch thick--just to handle it. We were very ear ul that

the tolerances and pitting would be horrible. So we knew that we might

eventually mill it down to nominally hal an inch thick. So now the material

has a lot o spanning capacity. Hal an inch is pretty strong, which starts to

set up the sti ener depth, the sti ener rhythm, etc. So when you look at

the elevations, the continuous horizontal sti eners, and the intermittent

vertical sti eners correspond to working compositely with a 1/2 inch

material thickness. So i the material was 1/4 inch, there would be a lot more

sti eners, and they would all be deeper. The nal structural combination

was quite efcient.

The other thing is both lines o restraints are close to the top and bottom

so you can access them with tools once the panel is installed. You couldnt

put it in the middle because we werent going to build the waterproo ng

rom the inside out, so accessing the mid- eld o the large panel would be

impossible once it was set on its support brackets. We wanted to sew the

whole substrate assembly up ahead o time with regard to waterproo ng

and then eld water test it. Once the panels are on, getting in to x the

waterproo ng would be a nightmare. The interior nishes, the case work,

and the clothing would all be right there on the inside. You would have to

rip all that out, rip out the interior waterproo ng and try to do it rom the

inside; and the invasiveness o getting to it rom the outside is even worse--

imagine taking the panel o just to x a leak! So the idea was to get thewaterproo ng right the rst time and then ully protect it.

The next challenge was seismic movement - Los Angeles is one o the most

active earthquake zones in the world. We had originally settled on having

a 1/2-3/4 thick corner joint where the panels meet, because over the height

o the panel, the oors would rack during an earthquake by about that

dimension. Arup carried out the structural analysis or the building and

these nal movements were provided by them as a basis o design or the

exterior cladding team. Which means that the panel on the side would

stay in a rectangular con guration and would just get dragged back and

orth sideways without racking. The ront panel would be connected to

two oors, one moving and one not, so it would actually be changing its

inclination relative to the vertical.

This was going to happen no matter what kind o joint we had. We were

all ear ul that i you didnt have a joint, the corner would just rip itsel open


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during any kind o serious earthquake. We had to design to a level that

under an elastic seismic event, the panels had to be ully serviceable; they

have to return to their original condition without requiring any urther

work. In an inelastic seismic event, which is really catastrophic, they are

not allowed to come o the building but it would be ne or them to be

damaged. Sa ety rst! There is always the risk that one panel would rip

another o its bearings, all the wind-load restraints would pop out rom theorce created by the racking and the panel might actually rip o .

However, it became clear a ter a ew quick 1:1 mock-ups that 1/2 - 3/4 inch

joint would totally destroy the conceptual e ort going into building the

ront panel. I you are going to take the trouble to abricate a monolithic

ront panel, youve got to nd a way to eliminate the joint. So the way to

do that is to take all three panels and lock them up seismically. That means

locking each corner up like a piano hinge. So when it moves thermally,

one panel actually twists. Now the rst connection or the panel has to belocated slightly away rom the corner so there is room or the metal to bend

without producing a permanent cold ormed de ormation in the material.

A ter that you have to release the bottom so that it is no longer connected to

the primary steel work. So now where is the windload rom the bottom o

the panel going?

Well, you have these two side-panels that can work as a kind o shear wall.

The only way to do this was to build a horizontal truss above the soft

panels, much like the roo but much lighter. The truss would then lock up

all three hal inch thick panels ( ront, side, side), with all panels supported

by deadload hangers rom the soft above. The whole thing then sits under

its own gravity, but under an earthquake, the box just swings rom the top,

moving back and orth independent o the oors since it is no longer tied at

the bottom to the primary structure.

A company called United Aircra t Engineering in St. Louis had an 80 by 240

oot milling bed that they normally use to mill aircra t wings. We were really

worried about the tolerances o this huge sheet o aluminum coming out

o the actory, UAE was able to grind the panels down rom 7/8 to 1/2 inch.

They also had a shear big enough to cut the 42 eet dimension all in one go.

At the end o the day, they were able to get the diagonal tolerance to 1/16

inch over the entire sheet. The diagonal. Pretty amazing. The panels were

too big to be anodized (they wouldnt t in any bath), so the nal nish is

hand-applied, done by Italian artisans imported by Prada and put to work inLong Beach.

The acade contracting business is kind o like the car industry: the good

companies know thousands o suppliers. They can outsource a component

or process that makes the project possible. Sometimes the consultant does

this work instead-- identi ying specialist abricators and nominating them

to the acade contractors. The manu acturers o ten service other industries

because they have developed such a specialty. A lot o the companies we

deal with to do acade work do industrial, marine, automotive, and aircra tcomponents. These industries have very high-tolerance demands that

buildings only rarely require, let alone a ord.

The Beverly Hills Store was one o these rare projects, and was executed

with extreme precision-- I could tell similar stories about the roo which is

100 percent skylight while serving as a horizontal Vierendeel rame or the

building, or the berglass cone and elliptical glass oor display windows, or

the Liquid Crystal projection screens, or the 40 oot wide aluminum ront

door that is ully retractable into the ground, and certainly an entire book

could be written about the development o OMAs sponge material.

An exquisite undertaking.

Marc Simmons is a partner in Front Inc., a acade consultancy ofce based in New York City.

To date they have consulted on projects with SANAA, OMA, Herzog & de Meuron, and Renzo

Piano among others. Marc Simmons was interviewed at Fronts ofce on March 6, 2007.

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