good morning and welcome to the special meeting for today march 25, 2013 directors sartipi is not available to attend. metcalf present, reiskin, kim present as well. madam chair you do have a quorum?

>> thank you, is there any new business? seeing none we move on to the directors report. >> good morning everyone. we have a full agenda today. i'm going to report on one item, preparatory school in palo alto shadowing us and they are from grades 6-12. all of these students graduate and go to college. i want to thank you for attending. that concludes my report. >> thank you. at this time we'll move to item # 6, which is a public comment. >> we don't have anyone who wishes to comment on this item. thank you, patrick from san francisco. i know you are

looking for areas to save money, i think you can save money in position decisions which include buildings that is right going to attach to the dooept. a policy decision that could be made easily. thank you very much. >> thank you, mr. part patrick. any other m members for public comment? thank you no comment. item is closed. next comment? item?

>> update and vulnerability assessment in the construction document. >> directors will be part on this item? >> thank you, chair. executive members, board. bob with p a. i want to provide you on an update today on two aspects of the design flt . in the past 2 board meetings we've updated you on the project. in the meantime the design team is making good problem on the construction documents and there are two aspects of the design which we felt was important to seek guidance from

the board. the first is value of engineering of the w 1 awning system and the rba design guidance criteria in the construction document preparation and i will speak more on that after fred presents. >> thank you, bob. good morning directors. my name is fred clark. i'm a senior design principle architect for the transit center. we want today to bring you into discussion and development of the exterior wall of the building changing from glass to exterior wall.

it's a change. the critical issues even though these are dramatically different materials, the critical issues that they still have certain aspects in common. one is that since the days of the competition we've always envisioned the transit center, even those it a very light building, it touches the ground very lightly and we felt the glass did that and metal does that equally well. the other thing that is very important that this is going to be the centerpiece of an entirely new neighborhood in san francisco. it has to be a great neighbor, it has to be a welcoming civilized humane presence and a building you want to live in and the wall does it equally.

will : what you are seeing today, even though there are a number of the options, all of them will be what you will see today which has no discernable or dangerous scheduling impact on the work at hand. the construction documents are due may 31st, that will be the target we hit. the system is a design build system. that design build package is going to be delayed a little bit because of this change but not in a material fashion. so what you have seen today fits in the schedule and cost parameters. >> can i ask a brief question. when you say it fit in cost parameters, what cost parameters? >> the idea is to save some $17

million to achieve the target. what i wanted to note that first is an aspects are still being developed but all within that save target. so the images on the screen are not always wonderful. sorry about that. but what you see is an oddly crop image of the building as it was previously. this is a grass exterior wall and that is one of the reasons we brought the prints to the room. this is the new metal exterior wall. we are looking at the following options. no. 1 we are looking at an aluminum panel, we are looking at a

stainless steel panel which is thicker, outside of our cost parameters and we are looking at a painted aluminum panel and i will pass these around so you can see what we are talking about. in the blowups the building will result in a light silvery wall with a great deal of character. it changes appearance during the daytime as the light changes. it is a very lively exterior presence. here you see the glass version and metal version on beel street. it had a pattern that made the opaque part 40 percent opaque, the clear part was 60 percent clear. in the metal

version we have reversed that. in the holes in the metal, they are 40 percent. essentially we have taken the opacity in the glass and metal and reversed those. we do those for strength and visual reasons. we felt the 60/40 perforation is the most satisfactory. the interesting thing about the building is that as you can see it's a very complex form, but it's a form that's made up of modular parts. the most fundamental aspects of the course is what you call a super structure which you see here. this will be an important issue later when we talk about lighting. it a very large light piece of construction. that

gets fitted with a substructure which holds the interior wall in place and it's the subject structure that starts to define, the geometry of the exterior wall that substructure is then covered with a panel previously it was a glass panel, currently it's going to be a metal panel and what i'm going to do now is take that one piece of metal panel and talk about what it takes to design it and construct it as we convert to metal. what is interesting about that subject substructure it dissolves itself into 8 unique shapes. the colors that you see here define those 8 unique shapes. in order to achieve the curved panel, each of these substructural pieces is actually a trapezoid in shape. if you blew up any of those

colors you would find that even though they might look squared from a distance, there are no right angle corners. that's important to the ultimate patterning of the wall itself. but in that we also saw distinct opportunities just as in the glass panel which would create a unique identity for the transit center in solving the geometry and perforation of the wall, we felt there was an opportunity to create something that was really quite unique to the transit center and a pattern that might be called to the center itself. it led to us reexamine some of our earlier thoughts. this is pattern in reverse of the glass. this was if you imagine that the glass panel previously was a dot pattern, 60/40 perforation to opaque. if we rendered that in metal this is what it would

look like and that pattern has an underlying grid lock pane to it. if it were a trapezoidal shape or non-angle corner. it would look sloppy at the edges. that presented an opportunity for us that we'll get to in just a minute. there are various patterns. this is a snowflake pattern that are interesting mathematically derived crystal lion like forms and they are in grid like structures called periodic structures. our panels are not really right angled panels. they are trapezoidal shape so it caused us to look beyond grid like patterns. after a bit of research we found other

scientific relationships. this is an electron microscope photograph of the atomic structure of an aluminum alloy, very similar to the aluminum alloy that we are proposed for the building itself. it's also a very good example of what's called a quasi crystal or non-periodic pattern. even those there is elements that repeat, there is no grid structure to it. it's one of the ideas behind the 2011, to understand what a quasi crystal non-periodic pattern in nature. from england it came from a similar idea called the

pen rows panel. it repeats in a fashion. since it's not periodic, it's not grid like. it can be tut cut at the edges without any resulting -- sargs. when it's cut at a non-right angle, the edges become rather frayed. you can see the pen rows panel adapts quite readily to the edges of the building. we started becoming very interested in the idea of the kind of crosscurrent of

science, engineeringnd architecture and art that all come together that looks at patterning quite well. it looks an is a narrative to key into the bay area. all of the areas have similar underlying values and if that narrative is built into building it could become quite powerful. it's also a series of dots and there is a great range in how one might render the building to start to the developed. let me pass down the materials and colors we are looking at. so the first piece that you see here is clear anodized aluminum in the pen rows pattern. that is an 18 inch square. the panel

itself is roughly the size of two of those boards. so that panel is '116 of the whole panel exterior wall. there are no curves in these panels but the way the panels are motion to dismiss motion -- the panel will be '3'18 inch square. the panel itself is roughly the size of two of those boards. so that panel is '116 of the whole panel exterior wall. there are no curves in these panels but the way the panels are -- the panel will be '316 of an inch thick. it will be a very controllable surface, very beautiful surface. what is interesting about this idea is that there are a number of metal panel buildings in san francisco. one of the ones that has aged the best is macky art center. the sidewall of that the building is also clear

anodized aluminum. it looks as handsome as the day it was first finished. we believe it's a good choice. it's also possible to be painted. it has a white finish. it possible we might use the same white as the finish for the new metal exterior wall. this is a choice we can make later. if you look at it carefully at the sample being passed around, there is a metal flake quality to it that creates a very light surface. you'll another option which is another form of paint which has an ir -- it might be related to

the tower but different, a very lively exterior wall. we have to look at it carefully on-site. the third option is stainless steel. it's out of our cost parameters. we can entertain it to ask whether it could be steel. it may look very handsome like if we look at the disney concert hall in a los angeles, those are gastrointestinal steel structures. frank gary's famous

buildings. those are options. i will go to close-ups to show how the wall might seem in detail. although the the building is curved, it's made up of flat panels that are facetted curved shaepd shapes. the lowest the building gets to the ground is the molding as the wall turns to the ceiling. one of those panels is 16 of those small samples you just sent. although that pen rows apparently panel that you see here is appropriate. so this is that same view, but rendered in the pen rows pattern. this is with lines

rather than dots. you can see that instantly that it's a very beautiful wall. but we think equally handsome. this is again why we brought the large gloss because it's hard to appreciate on the screen, delicacy and unique pattern. it's slightly more dense, this is a bit more metal in this version than there is open but it's also quite beautiful. once again that's what you see in this panel. one question is what would this be like inside. one shows the previous glass version and bear in mind that previous forms, the wall was 60 percent transparent versus 40

percent in the pen rows pattern is the issue being looked at here. this is interior view when the the building is wrapped in the per forted metal skin. it's what one finds in a theatrical stage, it's a very beautiful kind of warm presence and a very unique place to be inside of, particularly the bus deck which is where this view is taken from. we also saw other opportunities in the change from glass to metal that come about because once again this is a less transparent wall, this is like a theatrical set which creates drama in the evening and lighting in the building. the last two images

here shows two ideas. one idea on the left is to light that massive super structure that you see running 5 blocks from one end to the other. if just those 2 big columns are lit from the street to the park with a beautiful presence also an led light source which might be used for special occasions. it might be programmed and be used to celebrate anything from holidays to winning the world series again which is bound to happen. so we think the building itself then becomes a very lively presence in the city. and i believe that's everything

that we have. >> great, are there any questions from directors? >> director reiskin. yes. i would like to comment you and the team to what seems a lot of stop has come to this and 2 challenges which is the vulnerability of the initial design and the cost. it's great. i have a number of small questions. the first is the increased opacity. what does that do to the demands for interior art, interior lighting and the energy use of the building and lead issues? >> well, we are study that right now. we are trying not to have increased usage of

artificial light inside the building. we have a number of light sources including a natural light tube that brings like from the park level that is still there even with the metal scan. but to be obvious it's a technical question we are looking at now. the opacity is flexible. we may wind up with 50/50 percent proliferation. >> in terms of -- this is -- would be more open air than the glass configuration? >> it's a per fraetd skin. in both cases the skin is hanging out from the