Honoring Pittsburgh's Bridge Legacy: The Three Sisters Bridge Restoration Project

WEBVTT
00:00:00.000 --> 00:00:17.360
Music.
00:00:17.458 --> 00:00:21.718
Gearing up for our 58th Annual Engineering Excellence Awards.
00:00:21.918 --> 00:00:26.558
And today we want to focus on one of the projects that is going to be awarded
00:00:26.558 --> 00:00:32.838
an honor award at that event in May, and that is from Michael Baker International
00:00:32.838 --> 00:00:34.758
out of Pittsburgh, Pennsylvania.
00:00:34.758 --> 00:00:37.738
And we're talking about the Three Sisters Bridges.
00:00:37.858 --> 00:00:42.578
Now, if you are familiar with or have ever watched a Pittsburgh Steelers game
00:00:42.578 --> 00:00:46.658
or you know of Pittsburgh, you know it is a city of bridges.
00:00:46.658 --> 00:00:53.498
And there are three bridges that are really historic because they are the only
00:00:53.498 --> 00:00:58.558
bridges of identical side-by-side crossings in the world, essentially identical
00:00:58.558 --> 00:01:01.198
but different in many different ways.
00:01:01.238 --> 00:01:06.338
We're talking about, first, the Roberto Clemente Bridge, the 6th Street Bridge,
00:01:06.538 --> 00:01:12.238
the Andy Warhol Bridge, which is the 7th Street Bridge, and the Rachel Carson 9th Street Bridge.
00:01:12.238 --> 00:01:19.058
And they all cross the Allegheny River, and they are really one of the biggest landmarks in the city.
00:01:19.638 --> 00:01:24.238
But they've been around for a while, since the early 1920s, and the weather
00:01:24.238 --> 00:01:26.898
and the environment takes its toll, especially in Pittsburgh,
00:01:27.198 --> 00:01:29.318
and they need to be rehabilitated.
00:01:29.578 --> 00:01:31.878
Michael Baker International was brought in to do that project,
00:01:32.098 --> 00:01:34.758
and their work has earned them an honor award.
00:01:34.858 --> 00:01:40.278
So I'm very pleased to be joined today by Aaron Colorito. He is the technical
00:01:40.278 --> 00:01:42.518
manager, Bridges, for Michael Baker International.
00:01:42.818 --> 00:01:46.138
Thank you, Aaron, for joining us to talk about the project. Thanks for having
00:01:46.138 --> 00:01:47.178
me. Really appreciate it.
00:01:49.058 --> 00:01:52.078
So this is something else because, I mean, really, you know,
00:01:52.138 --> 00:01:55.018
I'm a Pennsylvanian myself, so from the other side of the state,
00:01:55.178 --> 00:01:57.258
but, you know, everybody knows Pittsburgh, right?
00:01:58.058 --> 00:02:01.598
And you can't not know these bridges.
00:02:02.518 --> 00:02:07.198
They are just really unique to the city. I mean, how was it to get really to
00:02:07.198 --> 00:02:11.198
work on such an identifiable landmark for a city?
00:02:11.518 --> 00:02:16.098
It's really something because I started, I graduated college.
00:02:16.098 --> 00:02:20.778
I had got a master's degree in 2011 in Cleveland. And I spent a couple of years
00:02:20.778 --> 00:02:22.258
working for a small consultant there.
00:02:22.318 --> 00:02:26.998
And I had interned with Michael Baker before and kind of worked on just when
00:02:26.998 --> 00:02:30.098
Michael Baker got in the contract and just kind of dabbled in it.
00:02:30.098 --> 00:02:36.338
But you can't walk two steps anywhere in the city without either being able
00:02:36.338 --> 00:02:40.938
to see them or they're on a billboard, they're on someone's logo,
00:02:41.218 --> 00:02:46.358
they're on the jumbotrons at the Penguins and the Pirates games.
00:02:46.398 --> 00:02:50.978
You really can't go far without seeing some image of these bridges somewhere.
00:02:51.438 --> 00:02:55.658
So I've worked on them at this point for basically my entire career.
00:02:56.348 --> 00:03:01.708
And it's really been something. Yeah, I mean, looking at just the fact that
00:03:01.708 --> 00:03:06.588
they're built in the 1920s first and they've been servicing,
00:03:06.588 --> 00:03:09.188
you know, an entire population in the city.
00:03:09.388 --> 00:03:13.688
There's a lot there, historical significance and just how do you approach the project.
00:03:13.868 --> 00:03:18.788
What are some of the challenges that the firm faced when rehabbing these bridges?
00:03:19.068 --> 00:03:22.348
You know, there are three separate bridges designed at the same time,
00:03:22.488 --> 00:03:25.168
but, you know, they're all different in their own special way.
00:03:25.168 --> 00:03:30.048
Yeah, it's funny because they are, you know, we call them the three sisters.
00:03:30.268 --> 00:03:34.768
They're identical for all intents and purposes. They are this type of bridge
00:03:34.768 --> 00:03:36.228
had only ever been done once before.
00:03:36.788 --> 00:03:41.388
And there was a crossing over, I think it was the Rhine river in Cologne, Germany.
00:03:41.828 --> 00:03:46.268
It was built in 1915 ish. And if you look at pictures of it,
00:03:46.308 --> 00:03:50.208
I mean, the portal looks the same with the kind of windows in it.
00:03:50.448 --> 00:03:53.708
It's almost if they had copy paste back then, it was almost copy paste.
00:03:54.348 --> 00:03:57.328
So they you know designed and built the seventh
00:03:57.328 --> 00:04:00.308
street bridge was kind of the prototype that one
00:04:00.308 --> 00:04:03.248
was done first and then the sixth and ninth street bridges the
00:04:03.248 --> 00:04:08.088
ones that are on either side are slightly different from seventh street seventh
00:04:08.088 --> 00:04:12.308
is slightly narrower and slightly longer but sixth and ninth were actually produced
00:04:12.308 --> 00:04:16.688
from the same set of shop drawings actually you know sixth street bridge is
00:04:16.688 --> 00:04:22.388
written nicely in the title block and then handwritten above it is and 9th Street Bridge on top of it.
00:04:23.648 --> 00:04:27.248
But, I mean, they're really cool bridges designed and built by the American
00:04:27.248 --> 00:04:30.648
Bridge Company or not designed, I should say built by the American Bridge Company.
00:04:30.648 --> 00:04:32.568
They were designed by Allegheny County.
00:04:33.148 --> 00:04:36.748
I'm actually from Ambridge, you know, the company town. There you go.
00:04:37.168 --> 00:04:39.748
My grandfather was a drafter for them for many years. Oh, wow.
00:04:39.808 --> 00:04:43.328
So you actually, this is multi-generational for you. I mean,
00:04:43.388 --> 00:04:44.768
this goes back to I've got them in my blood.
00:04:45.188 --> 00:04:47.488
Yeah, that's cool. Yeah.
00:04:47.868 --> 00:04:51.408
Yeah. And they've, you know, they're not the first bridges at these sites.
00:04:52.308 --> 00:04:55.368
Sixth Street Bridge is actually the fourth, or I should say the Clemente Bridge
00:04:55.368 --> 00:04:56.588
is actually the fourth bridge there.
00:04:56.788 --> 00:04:59.988
It replaced a suspension bridge that John Roebling had designed,
00:05:00.188 --> 00:05:01.548
you know, one of his first ones.
00:05:01.968 --> 00:05:07.308
And it kind of gave them the first inkling that a traditional suspension bridge
00:05:07.308 --> 00:05:12.868
wasn't going to work because the soils in that part of the town are not great.
00:05:12.868 --> 00:05:15.728
So they built it and actually the anchor just started
00:05:15.728 --> 00:05:18.708
slipping so they would add more
00:05:18.708 --> 00:05:21.508
weight to it and just kind of hope and pray that
00:05:21.508 --> 00:05:27.668
it would be all right so about i want to say it was i think it was around 1918
00:05:27.668 --> 00:05:34.248
1914 somewhere right after world war one so 1819 there's actually a mandate
00:05:34.248 --> 00:05:40.188
from the department of war you know what it was called back then that all cities
00:05:40.188 --> 00:05:41.488
that had navigable rivers,
00:05:41.688 --> 00:05:46.568
they wanted all the rock river crossings had to be raised so you could get a warship under it.
00:05:47.748 --> 00:05:52.248
And right now, back then and right now, 6th, 7th and 9th street are the lowest
00:05:52.248 --> 00:05:53.488
crossings on the Allegheny.
00:05:54.548 --> 00:05:57.448
And they were, the city was mandated to raise them.
00:05:58.648 --> 00:06:02.508
So they put forth a whole bunch of different concepts, you know,
00:06:02.608 --> 00:06:06.128
lift bridges, suspension bridges, truss bridges.
00:06:06.868 --> 00:06:12.568
But you're so confined in that area, going into town, and then especially on
00:06:12.568 --> 00:06:17.388
the other side of the river, what's now the North Shore, that was a different city at that time, too.
00:06:17.508 --> 00:06:21.968
That was Allegheny City. So it was a completely different set of folks that you had to work with.
00:06:22.568 --> 00:06:26.888
So they had an art commission back in that rejected all of the prototypes,
00:06:27.088 --> 00:06:28.548
all of the types that they put forth.
00:06:29.688 --> 00:06:34.848
So about that time was when probably the county got word of that self-anchored
00:06:34.848 --> 00:06:36.468
suspension bridge that had been built in Germany.
00:06:37.228 --> 00:06:40.268
And there was a paper written about it. They looked at it and said,
00:06:40.448 --> 00:06:41.608
all right, let's give this a shot.
00:06:41.928 --> 00:06:46.668
The art commission accepted it. So they went ahead and designed and built all three of them.
00:06:47.068 --> 00:06:53.148
Oh, man. Yeah, I, looking back at some of the, I mean, did you go back into
00:06:53.148 --> 00:06:58.048
the original, some of the original designs and some of the early drafts on that
00:06:58.048 --> 00:07:01.568
bridge back from the, from the, you know, 1910 and 1900s?
00:07:01.708 --> 00:07:06.528
There were a couple of images, like kind of drawings, renderings,
00:07:06.708 --> 00:07:08.608
but nothing that was design wise.
00:07:08.808 --> 00:07:11.988
We didn't, we were actually really lucky. They had, the county still had the
00:07:11.988 --> 00:07:14.548
original design calcs for the
00:07:14.548 --> 00:07:17.648
bridges. And it was really funny because they're, it's about this thick.
00:07:18.688 --> 00:07:23.908
It's maybe a hundred pages, you know, and I feel like today one of my,
00:07:24.624 --> 00:07:28.724
One of my slim calc books is maybe like 16,000 pages or something like that.
00:07:31.084 --> 00:07:35.644
But yeah, and they designed and built them with, you know, the design drawings
00:07:35.644 --> 00:07:37.024
for about 30 sheets a piece.
00:07:37.184 --> 00:07:40.124
The shop drawings are about 90 to 100. Yeah.
00:07:40.724 --> 00:07:42.564
It took us 150 to rehabilitate them.
00:07:43.984 --> 00:07:46.964
You know, looking, I mean, applying a lot of modern, I mean,
00:07:47.024 --> 00:07:49.844
how did you apply those modern techniques, the engineering practices,
00:07:50.204 --> 00:07:55.304
with the bridges keeping that structural integrity, keeping that historic integrity
00:07:55.304 --> 00:08:02.064
in place, but, you know, applying some more of the modern engineering practices?
00:08:02.424 --> 00:08:06.464
So it started out with, you know, reviewing those original calcs.
00:08:06.764 --> 00:08:10.444
And we found that they had a couple of errors even back then.
00:08:10.924 --> 00:08:16.804
So when we did that, and then all through the years, the bridges had never been analyzed in 3D.
00:08:17.184 --> 00:08:20.684
Not once. So we said, well, we're going to try doing it in 3D,
00:08:20.824 --> 00:08:23.884
3D finite element, just to see kind of, we were interested,
00:08:24.124 --> 00:08:28.904
especially because, you know, these bridges are loved so much that we will close
00:08:28.904 --> 00:08:32.384
them down to traffic and put festivals, parties.
00:08:32.884 --> 00:08:37.724
There's a boxing ring on one, the Picklesburg Festival, all kinds of different
00:08:37.724 --> 00:08:38.544
things that were on them.
00:08:38.544 --> 00:08:44.524
So what we were really interested in was seeing how if you model crowds of pedestrians.
00:08:45.084 --> 00:08:47.884
On it you know how does the bridge react kind of
00:08:47.884 --> 00:08:51.304
it doesn't want to torque does it want to twist you know
00:08:51.304 --> 00:08:53.984
what happens there so that was kind
00:08:53.984 --> 00:08:57.044
of the first shot and then once we started really
00:08:57.044 --> 00:09:00.164
digging deep into repairs and
00:09:00.164 --> 00:09:02.924
designing you know the repairs and their
00:09:02.924 --> 00:09:05.884
connections we started to realize that a lot
00:09:05.884 --> 00:09:08.764
of places we were actually pushed at
00:09:08.764 --> 00:09:11.904
the very beginning to use rivets new rivets in
00:09:11.904 --> 00:09:15.544
construction and just based
00:09:15.544 --> 00:09:18.384
on you know there's their nature and you found in
00:09:18.384 --> 00:09:21.384
a lot of places that they wouldn't you
00:09:21.384 --> 00:09:24.764
know even if you were able to drive a new rivet using
00:09:24.764 --> 00:09:27.724
like an old rivet spec like a502 from
00:09:27.724 --> 00:09:30.844
astm they wouldn't work either there's just
00:09:30.844 --> 00:09:35.884
two modern lows are just too heavy so at
00:09:35.884 --> 00:09:40.844
the time at least i thought maybe because i had a lot of hopes and dreams and
00:09:40.844 --> 00:09:46.444
sparkle left on my eyes back when we started that i would just provide that
00:09:46.444 --> 00:09:51.284
information and then everyone would be satisfied and it was just the beginning,
00:09:52.424 --> 00:09:57.484
because in in this you know we have there's multiple multiple stakeholders from.
00:09:58.797 --> 00:10:02.197
Just from the city and the county themselves, there's PennDOT,
00:10:02.377 --> 00:10:05.237
there's the Coast Guard, there's all the people that live and work there.
00:10:05.957 --> 00:10:09.837
You know, PNC Park is about 18 feet from the end of the mining bridge.
00:10:10.377 --> 00:10:16.417
Yeah, so, and then the big issue that we ran into was with the SHPO,
00:10:16.637 --> 00:10:20.977
State Historic Preservation Office, and the Pittsburgh Historic Museum Commission.
00:10:21.637 --> 00:10:26.677
They were wanted to really know that there was no way that we could use rivets.
00:10:26.677 --> 00:10:30.697
So actually you know i have this thing that i've been i've dragged around the
00:10:30.697 --> 00:10:37.977
country with me for show and tell was to show well to explain to people really
00:10:37.977 --> 00:10:41.817
like is this you know an option so,
00:10:42.357 --> 00:10:47.577
i had knocked something together out of wood in my garage at one point and got
00:10:47.577 --> 00:10:50.137
some a chance to make it out of steel because i was like it should be made out
00:10:50.137 --> 00:10:56.577
of steel but to say okay if i take This is a rivet from one of the Three Sisters Bridges,
00:10:56.617 --> 00:11:00.877
and you put it next to an A325 bolt. I mean, you could tell they're different.
00:11:01.977 --> 00:11:06.457
So one of these possible solutions that someone had thrown out was,
00:11:06.637 --> 00:11:14.097
is there some way we could take a plastic cap or something to snap on or to emulate it?
00:11:14.197 --> 00:11:17.017
And I said, okay, well, let me think about that.
00:11:17.017 --> 00:11:21.597
And about a dollar later and a couple of, you know, half hour at Hobby Lobby,
00:11:21.777 --> 00:11:29.197
I said, okay, well, that's how big your cap would need to be just to cover the head end.
00:11:29.297 --> 00:11:33.077
And that's not even counting the nut end, which could have any amount of stick out.
00:11:33.377 --> 00:11:36.717
So they were pretty satisfied that that wasn't a good idea.
00:11:37.357 --> 00:11:41.997
So, you know, I threw out there, we have, you know, there's an alternate to hex headed bolts.
00:11:41.997 --> 00:11:47.197
There's the F1852 tension control bolts that have, you know,
00:11:47.277 --> 00:11:51.137
it's still a nut on one end, but you have this advantage of having the domed,
00:11:51.137 --> 00:11:54.017
you know, button head on the other. And.
00:11:54.756 --> 00:11:58.536
You know, just by happenstance, you know, their head for the proportions of
00:11:58.536 --> 00:12:02.356
the head when you're looking at it and you're just walking by pretty much the
00:12:02.356 --> 00:12:08.196
same, especially once you get, you know, a real industrial three coat paint system on there.
00:12:08.516 --> 00:12:11.616
You can't tell to just a lay person.
00:12:11.876 --> 00:12:16.476
So we made an effort. We said, would this be an acceptable solution if we were
00:12:16.476 --> 00:12:21.236
to, you know, make sure that we orient the heads, you know, to where people would see them the most?
00:12:21.816 --> 00:12:26.716
And that was an acceptable solution to everyone. So we actually had some language
00:12:26.716 --> 00:12:30.356
in the drawings and in the specifications to say, Mr.
00:12:30.476 --> 00:12:32.876
Contractor, you must use these bolts everywhere you can.
00:12:33.416 --> 00:12:36.476
There's a couple of places here and there where you can't get them domestic
00:12:36.476 --> 00:12:43.976
or we might have needed, there's a repair where we needed about 20 of them of a very specific size.
00:12:44.256 --> 00:12:49.736
And they said, well, we could either get them from Japan or we can order a cask of 6,000.
00:12:50.916 --> 00:12:55.576
That's the minimum order for these. I think it will be okay if we use hex headed
00:12:55.576 --> 00:12:57.836
bolts here in that situation.
00:12:58.316 --> 00:13:01.496
Yeah, that compromises the, you know, compromises a beautiful thing.
00:13:02.156 --> 00:13:06.336
Especially when it works your way. Exactly. But I think that really underscores
00:13:06.336 --> 00:13:13.496
the amount of care that goes into the restoration work on these cherished pieces
00:13:13.496 --> 00:13:14.696
of infrastructure, right?
00:13:14.696 --> 00:13:18.436
I mean, you know, there are going to be interest groups that,
00:13:18.456 --> 00:13:23.556
of course, will focus specifically on the size diameter of a bolt,
00:13:23.696 --> 00:13:25.876
you know, without question, right? This is what they do.
00:13:26.236 --> 00:13:30.676
But the general public is going to see it and go, well, you know, it looks the same.
00:13:31.936 --> 00:13:37.576
But the care and detail that, you know, you went home, you created a mock-up
00:13:37.576 --> 00:13:43.096
out of wood in your own garage to do, you know, to demonstrate and then to bring up options.
00:13:43.096 --> 00:13:46.576
And, and, and I think it just, there are a lot of people out there who are like,
00:13:46.656 --> 00:13:49.056
okay, they, they rehabbed the bridges and it looks great.
00:13:49.236 --> 00:13:52.036
And, and, and it's, you know, it's going to be safer, but they don't realize
00:13:52.036 --> 00:13:56.836
exactly how detailed these, these projects go. Oh yeah. Yeah.
00:13:58.736 --> 00:14:02.116
It's difficult, especially when you get questions from, you know,
00:14:02.176 --> 00:14:04.436
our friends, family, you know, what's going on? How do you do that?
00:14:04.436 --> 00:14:06.556
And I said, well, do you have an hour?
00:14:06.736 --> 00:14:10.616
Cause that's kind of what I need to really drill down and explain it to you.
00:14:10.616 --> 00:14:13.776
They said could you give it to me in 25 seconds
00:14:13.776 --> 00:14:16.576
we're fixing it there you go
00:14:16.576 --> 00:14:19.636
yeah well i you know when you mentioned the
00:14:19.636 --> 00:14:25.036
3d modeling and the fact that you were able to kind of do the dynamics of crowds
00:14:25.036 --> 00:14:29.856
on the bridge or different traffic patterns on the bridge and use cases not
00:14:29.856 --> 00:14:34.876
just you know travel with with with vehicles i mean you know having that i mean
00:14:34.876 --> 00:14:36.736
that's going to correct me if I'm wrong,
00:14:36.796 --> 00:14:39.136
but that's going to help in the future.
00:14:39.496 --> 00:14:42.616
It really is that digital modeling that's going to help,
00:14:43.368 --> 00:14:46.288
define how these bridges can use tolerances and the
00:14:46.288 --> 00:14:49.788
like so it really is a creating an entire new
00:14:49.788 --> 00:14:52.668
chapter for these bridges that have been around for
00:14:52.668 --> 00:14:55.368
you over a century that now you have
00:14:55.368 --> 00:14:58.448
a better because everything before was yeah we'll do a festival on the bridge
00:14:58.448 --> 00:15:01.888
it should be fine it's been standing up since 1920 so it's not nothing's going
00:15:01.888 --> 00:15:06.868
to happen but now you actually have detail and say here are the tolerances of
00:15:06.868 --> 00:15:13.728
this bridge yeah now we can the county now can because you You know, it's the cap, the funds,
00:15:13.928 --> 00:15:17.548
even more fun thing about it, I should say is, you know, the county owns the bridge.
00:15:18.088 --> 00:15:22.988
The city of Pittsburgh owns the streets that lead up to it. You know, the Coast Guard and the.
00:15:24.248 --> 00:15:27.588
Deals with the river, and then you have Penn dot who owns the street there,
00:15:27.848 --> 00:15:29.168
the road that runs underneath it.
00:15:29.328 --> 00:15:33.468
So there's a lot of coordination that has to go between all these players when,
00:15:33.688 --> 00:15:36.748
for example, they want to close one of the bridges, you know,
00:15:36.808 --> 00:15:39.628
except for a pirate game where that's that's an event.
00:15:39.628 --> 00:15:43.408
If they do it during the day or something it's pretty common and
00:15:43.408 --> 00:15:46.668
the great thing about these bridges especially doing
00:15:46.668 --> 00:15:50.468
the rehabs was we could close them down all
00:15:50.468 --> 00:15:53.268
the way because oh what's the detour just go to the next bridge
00:15:53.268 --> 00:15:56.028
over and then go to the next bridge after that if
00:15:56.028 --> 00:16:01.548
there's a problem over there so that was you know pretty unique part of it was
00:16:01.548 --> 00:16:07.968
still having to define a detour and not being able to put on the plans a picture
00:16:07.968 --> 00:16:11.348
of me just pointing to the distance where there's a bridge a couple of feet
00:16:11.348 --> 00:16:13.308
away that you could go to.
00:16:14.968 --> 00:16:23.108
How did you kind of roll in demands for sustainability into the bridge rehab project?
00:16:23.308 --> 00:16:26.948
You have to look at the structural side of things, but then also there's always
00:16:26.948 --> 00:16:33.568
a push for making sure that there is a sustainability function here going into it.
00:16:34.288 --> 00:16:38.828
So probably one of the biggest things that I would say is the great thing about
00:16:38.828 --> 00:16:43.168
the bridges is they're made out of steel, you know, and that's a little bit
00:16:43.168 --> 00:16:45.008
of preference on my part.
00:16:45.148 --> 00:16:49.568
I'm very much a steel guy, but especially modern steels, they're essentially
00:16:49.568 --> 00:16:50.728
a hundred percent recycled.
00:16:51.758 --> 00:16:57.458
Things that are used in an electric arc furnace, anywhere between 90% to 100% recycled.
00:16:58.138 --> 00:17:02.438
So that was a great place to start when we start thinking about sustainability.
00:17:03.638 --> 00:17:06.318
Now, you have to go the opposite end that we have to deal with concrete.
00:17:06.538 --> 00:17:08.738
Concrete's a pretty big CO2 producer.
00:17:08.938 --> 00:17:16.358
But as of this moment, we don't have, I would say, a lot of attractive alternatives to that.
00:17:16.358 --> 00:17:20.518
So we're kind of trying to play that balance of, you know, how do we,
00:17:20.518 --> 00:17:27.938
you know, how do we play with that to make, use, use the materials in a justified way.
00:17:29.118 --> 00:17:35.918
And then one of the big things I think that we did that kind of improved quality
00:17:35.918 --> 00:17:39.558
around the bridges was we cleaned all the masonry, all the subs,
00:17:39.678 --> 00:17:41.998
so all the masonry substructures, you know, they're sandstone.
00:17:41.998 --> 00:17:48.378
So they're basically, you know, a color anywhere from, this is a pretty typical
00:17:48.378 --> 00:17:50.978
color, actually, it's pretty close, you know, like a sandstone,
00:17:51.258 --> 00:17:53.778
a light brown, a little bit of orange kind of color.
00:17:54.598 --> 00:17:57.898
But, you know, they've been essentially gray and black for decades,
00:17:57.898 --> 00:18:00.458
you know, our sooty past.
00:18:00.658 --> 00:18:06.438
So we tried in our first contract with 7th Street, we had to input an item in
00:18:06.438 --> 00:18:09.018
the contract to say, hey, we're going to clean this masonry and we're going
00:18:09.018 --> 00:18:11.838
to do all these bridges one at a time. They're going to look great.
00:18:11.998 --> 00:18:15.238
We're going to get all that contamination and pollutants off of there.
00:18:16.038 --> 00:18:20.358
And then everything that we had put in there is like all these chemicals didn't work.
00:18:21.698 --> 00:18:25.218
So we had some options that we could try.
00:18:25.538 --> 00:18:29.038
The contractor that was working on the bridge at the time even brought out someone
00:18:29.038 --> 00:18:31.718
that had a laser that would actually burn.
00:18:32.158 --> 00:18:35.098
Oh, wow. So you're burning off the layer of sandstone.
00:18:35.738 --> 00:18:40.238
So we didn't like it for that reason that we could potentially damage a stone.
00:18:41.418 --> 00:18:44.558
It didn't get to the color that we thought it was it
00:18:44.558 --> 00:18:47.398
kind of just made it went from black to kind of like a darker gray
00:18:47.398 --> 00:18:54.718
like a lighter gray and then it was wildly expensive and it was slow it took
00:18:54.718 --> 00:18:59.118
you know an hour to clean maybe a couple of square feet and we had over 9700
00:18:59.118 --> 00:19:05.878
square yards of material total for all three bridges to clean so we went back to the drawing board,
00:19:06.518 --> 00:19:09.738
tried it again with the six street contract because we were already going to
00:19:09.738 --> 00:19:15.718
go back and touch all three bridges and we came up with another list of different things to try,
00:19:16.338 --> 00:19:20.518
contractor went out none of those worked so they
00:19:20.518 --> 00:19:25.938
actually had a masonry specialty subcontractor on the contract and they brought
00:19:25.938 --> 00:19:31.038
up the idea of doing a brace of blasting so with a very gentle it's actually
00:19:31.038 --> 00:19:35.238
it was glass beads mixed with water okay so like a silico i I was thinking silico
00:19:35.238 --> 00:19:37.278
or it's just like glass beads and water. Okay.
00:19:37.578 --> 00:19:40.198
So they did try a couple of things. They tried Black Beauty.
00:19:40.198 --> 00:19:46.078
They tried a couple of different grades of sand, but those beads ended up being
00:19:46.078 --> 00:19:47.538
a pretty good blend of sand.
00:19:48.203 --> 00:19:52.763
Aggressiveness, but they didn't remove the texture from the stones,
00:19:52.783 --> 00:19:58.323
which was actually a really important thing that we had to keep under control
00:19:58.323 --> 00:20:01.703
because below the deck level, all the masonry is just, you know,
00:20:01.783 --> 00:20:02.823
it's like rough cut stone.
00:20:03.223 --> 00:20:08.163
It's nicely dressed, but it's a rough face. When you get from deck level up,
00:20:08.403 --> 00:20:10.803
all that stone is hand textured.
00:20:11.083 --> 00:20:14.483
You know, it has a stippled finish on it that was done with like a bush hammer.
00:20:15.043 --> 00:20:18.063
It was physically a mason that would stand there and do that.
00:20:18.203 --> 00:20:20.023
So we couldn't lose that.
00:20:20.643 --> 00:20:26.643
So after the contractor got a couple of test patches, they were able to really dial the procedure in.
00:20:26.783 --> 00:20:31.863
And then all of that stuff they were able to collect either with turbidity curtains
00:20:31.863 --> 00:20:35.203
or sandbags and pumping.
00:20:35.683 --> 00:20:39.443
So they were able to collect all that waste, which, you know,
00:20:39.583 --> 00:20:41.363
luckily had no added chemicals.
00:20:41.583 --> 00:20:45.303
But, you know, we don't know what was it's mostly carbon probably just from soot.
00:20:45.563 --> 00:20:48.323
Yeah, but you never know. Right. And that's the you can't really. Exactly.
00:20:48.743 --> 00:20:52.483
Yeah. So, so it was all able to be collected, you know, stored,
00:20:52.643 --> 00:20:53.883
shipped, disposed of properly.
00:20:54.123 --> 00:20:58.303
So those are, I would say those are probably our two big, our two big pushes
00:20:58.303 --> 00:20:59.823
towards sustainability on those bridges.
00:21:00.003 --> 00:21:02.203
Those are not small pushes on sustainability.
00:21:02.523 --> 00:21:06.063
So, I mean, that, that, and that, I mean, that, but that makes everybody happy,
00:21:06.163 --> 00:21:07.603
right? So, so PennDOT's happy.
00:21:07.783 --> 00:21:11.803
DEP, I'm sure is happy because they have to, you know, figure out about,
00:21:12.023 --> 00:21:15.043
you know, what's going to be going into the Allegheny. But then it brings up
00:21:15.043 --> 00:21:17.143
the question of like, you know, just the other stakeholder groups,
00:21:17.263 --> 00:21:20.803
the community groups, you know, you mentioned, you know, everybody who was involved here.
00:21:21.363 --> 00:21:26.623
I mean, how did that how did you guys work with those groups just to keep them kind of happy,
00:21:26.763 --> 00:21:30.523
informed and on board with the project, especially, you know,
00:21:30.563 --> 00:21:35.643
the communities that are directly impacted by the bridges right around,
00:21:35.863 --> 00:21:37.363
you know, each of the bridges?
00:21:37.363 --> 00:21:42.923
Because, you know, Pittsburgh is a, it's a big city, but it's a fairly compact city.
00:21:43.063 --> 00:21:46.123
So these bridges do have a direct impact on the people living there.
00:21:46.343 --> 00:21:49.943
What was the community response to the project?
00:21:51.823 --> 00:21:57.983
The initial response was happiness mixed with a little bit of dread, I think.
00:21:58.963 --> 00:22:02.643
I think the initial response, I think people thought we were going to close
00:22:02.643 --> 00:22:05.663
all three bridges at the same time, which was never going to be the plan.
00:22:05.663 --> 00:22:07.723
I'm just kind of doing them one at a time.
00:22:08.263 --> 00:22:11.263
But at the same time, the last time I counted...
00:22:12.365 --> 00:22:16.545
Trying to actually put together an award submission was I lost count at 20 or
00:22:16.545 --> 00:22:19.045
25 different stakeholders.
00:22:19.945 --> 00:22:25.005
Not only just residents that live, there's an apartment community like right
00:22:25.005 --> 00:22:26.285
at the end of the 9th Street Bridge.
00:22:26.605 --> 00:22:30.205
You've got the people that live downtown on the south end of the bridges.
00:22:30.665 --> 00:22:34.825
And then there's a lot of people that work right at the north end of the bridges,
00:22:35.045 --> 00:22:37.785
notwithstanding PNC Park that's right there.
00:22:38.785 --> 00:22:42.305
So the biggest thing, and you said it when you were starting the question,
00:22:42.425 --> 00:22:43.445
was just communication.
00:22:43.985 --> 00:22:50.145
Is we figured that we had a sub-consultant with us that dealt specifically with
00:22:50.145 --> 00:22:51.485
communication, you know,
00:22:51.845 --> 00:22:56.265
press releases, and then working with Allegheny County Department of Public
00:22:56.265 --> 00:23:01.185
Works has their own press officer that we spent a lot of time going back and
00:23:01.185 --> 00:23:05.525
forth with him to make sure that if something was going to change,
00:23:05.765 --> 00:23:09.485
if something needed to be done at night, you know, people were aware of it.
00:23:09.885 --> 00:23:13.545
So like, for example, the enhanced lighting system that was installed on the
00:23:13.545 --> 00:23:17.065
bridges that has been of really nice success.
00:23:17.245 --> 00:23:22.525
You know, we had to do some work at night because one, if the contractor,
00:23:22.885 --> 00:23:27.785
the electrical subcontractor was working on a barge on a man left under the, on the river.
00:23:28.085 --> 00:23:31.425
So you have to work at a time where there's not a lot of river traffic.
00:23:31.665 --> 00:23:33.005
So naturally that's at night.
00:23:33.465 --> 00:23:39.225
And then also because they had a very limited amount of time that they could be in the river,
00:23:39.845 --> 00:23:44.025
essentially obstructing navigation, they wanted to make sure that when they
00:23:44.025 --> 00:23:47.925
installed these lights that they would look the way the county wanted to look,
00:23:48.325 --> 00:23:49.865
which meant doing it at night.
00:23:51.005 --> 00:23:54.705
So that enabled them to kind of set the light,
00:23:54.985 --> 00:23:59.565
everyone look at it, agree this is what we want, and then the electricians were
00:23:59.565 --> 00:24:03.145
able to build jigs that they could go when they went to the next location,
00:24:03.425 --> 00:24:06.105
just set a jig, set the fixture, and they knew that it would,
00:24:06.883 --> 00:24:09.663
be good but then of course you know you've got a man lift
00:24:09.663 --> 00:24:14.423
that might be moving you've got the barges so informing
00:24:14.423 --> 00:24:17.383
people that hey we're going to be working at night you're going to see lights you're
00:24:17.383 --> 00:24:21.523
it's going to be a little bit noisier but we're doing our best to limit the
00:24:21.523 --> 00:24:27.943
noise every project had a noise monitoring item you know within it so they had
00:24:27.943 --> 00:24:32.163
to constantly monitor you know construction site noise they weren't allowed
00:24:32.163 --> 00:24:36.083
to work certain hours let's say 99% of the time overnight,
00:24:36.463 --> 00:24:43.323
weekends, to try to intrude in people's lives as little as possible.
00:24:44.463 --> 00:24:47.423
And that really came to a head when we finished the Clemente Bridge,
00:24:47.623 --> 00:24:53.683
the Sixth Street Bridge, because none of the bridges had a large area to work around.
00:24:54.063 --> 00:24:58.383
The contractors are working on top of each other. You've got material stacked on the bridge itself.
00:25:00.303 --> 00:25:04.403
Sixth Street Bridge ends at Federal, it becomes Federal Street on the north
00:25:04.403 --> 00:25:07.983
side, that's where the pirates will have you know, family days,
00:25:08.243 --> 00:25:12.883
the inflatables and bounce houses and food trucks and all kind of stuff.
00:25:13.083 --> 00:25:15.863
So making sure that we would.
00:25:17.146 --> 00:25:24.666
Interfere with that as little as possible was a real was a real challenge. Yeah, I can imagine.
00:25:25.666 --> 00:25:30.526
From a, you know, it's wrapping it up. I it's it's just one of those projects
00:25:30.526 --> 00:25:33.806
that is going to have I, you know, with the rehabilitation, I guess.
00:25:33.946 --> 00:25:36.646
First off, I mean, with rehabilitation being done now, I mean,
00:25:36.686 --> 00:25:39.546
how many years does this add on to the lifespan of the bridges?
00:25:39.586 --> 00:25:44.626
Like when is the when is the next projected rehab going to have to happen after
00:25:44.626 --> 00:25:52.226
this project? So our goal was 50 years is, you know, we kind of established that as a minimum. Yeah.
00:25:52.726 --> 00:25:56.466
In all likelihood, you may need to come and do some deck work,
00:25:56.626 --> 00:25:59.986
probably maybe 25 to 30 years.
00:26:00.126 --> 00:26:04.566
The bridges will need painted in about 20, probably about 20, 25 years.
00:26:05.246 --> 00:26:08.446
And that's, you know, modern paints. That's pretty good.
00:26:08.746 --> 00:26:12.366
Yeah. So, I mean, really, I mean, essentially, you're looking at something that
00:26:12.366 --> 00:26:18.726
you worked on that is going to stand for at least 50 years until it's the next
00:26:18.726 --> 00:26:19.766
project is going to happen.
00:26:20.566 --> 00:26:23.746
I mean, you're looking back.
00:26:23.906 --> 00:26:26.486
I mean, you had members, like you said, members of your family that were that
00:26:26.486 --> 00:26:29.366
were essentially drafting with the company that actually built the original bridges.
00:26:29.586 --> 00:26:32.526
I wasn't mean to you because we always like to talk, you know,
00:26:32.666 --> 00:26:36.086
and people watching this and trying to get them engaged and interested in engineering.
00:26:37.086 --> 00:26:41.026
And the next generation, of course. But, you know, from a personal standpoint,
00:26:41.226 --> 00:26:42.006
professional standpoint,
00:26:42.286 --> 00:26:44.946
I mean, what does it mean to you to be able to work on a project like this that
00:26:44.946 --> 00:26:50.186
has such an impact and historical and then also be able to leave your mark on
00:26:50.186 --> 00:26:55.006
something which is such a loved piece of infrastructure in a city?
00:26:55.986 --> 00:27:00.706
It's, I mean, honor is what comes to mind, really, for me.
00:27:00.826 --> 00:27:05.106
And my wife will be the first one to tell you that I'm a huge nerd when it comes to bridges.
00:27:06.086 --> 00:27:08.646
Can't go anywhere without saying, oh, I don't like the way that is.
00:27:08.726 --> 00:27:10.506
And she goes, it's standing. It's fine. Leave it.
00:27:12.447 --> 00:27:16.327
But so much, these bridges have been, this project and these bridges have been
00:27:16.327 --> 00:27:19.847
such a huge part of my life over the last 10 years. Yeah.
00:27:20.227 --> 00:27:24.467
You know, before we were talking before that I have three children,
00:27:24.667 --> 00:27:29.367
six, four, and two, one of them was born during each and every one of these projects.
00:27:29.827 --> 00:27:32.767
Yeah. So, you know, I make the joke, I tell people, you know,
00:27:32.807 --> 00:27:35.667
my three boys, and they'll say, are they named after the bridges?
00:27:35.787 --> 00:27:41.587
So, yeah, my boys, Andy, Roberto, and Rachel are very near and dear to me.
00:27:41.587 --> 00:27:45.627
I guess that was not to be the pun intended, I guess, bridge too far for your
00:27:45.627 --> 00:27:47.327
wife if you want to do the movie, right?
00:27:50.247 --> 00:27:53.147
I knew better. Yeah. Better than to push that.
00:27:56.187 --> 00:27:59.867
Yeah, it's just fantastic. I mean, congratulations again. I mean,
00:27:59.927 --> 00:28:04.067
this is the kind of project that fits right into the awards program.
00:28:04.427 --> 00:28:08.147
Looking forward to, hopefully you're coming down for the program. I will be.
00:28:08.547 --> 00:28:12.967
Wonderful. So I get to see you in person. But for anybody out there,
00:28:13.067 --> 00:28:15.387
I mean, we're looking at a great awards program,
00:28:15.747 --> 00:28:19.387
of course, Three Sisters Bridges, one of many projects being awarded,
00:28:19.647 --> 00:28:23.987
but wanted to get special recognition to Michael Baker International for the
00:28:23.987 --> 00:28:25.467
work that they did on the project.
00:28:25.467 --> 00:28:29.127
And just next time you find yourself in Pittsburgh, inevitably,
00:28:29.167 --> 00:28:31.587
you'll probably find yourself on one of these bridges.
00:28:31.747 --> 00:28:36.287
And when you do, remember the people who actually made that possible to keep
00:28:36.287 --> 00:28:39.547
it standing for another 50 years and good standing and the history that went
00:28:39.547 --> 00:28:43.587
into it. So, Aaron, really appreciate you taking time to join us today.
00:28:43.987 --> 00:28:45.607
Thank you so much for having me. I had a great time.
00:28:46.067 --> 00:28:51.867
Awesome. Wonderful. Well, again, we have the Engineering Excellence Awards coming up in May.
00:28:52.880 --> 00:29:12.323
Music.