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# Pittsburgh bridge collapse32

## Pittsburgh bridge collapse

### RE: Pittsburgh bridge collapse

Is one trillion enough?

### RE: Pittsburgh bridge collapse

Here is the location:

This is not a small, forgotten bridge on a back road somewhere.

Construction P.E. (KY), MBA
Bridge Rehab, Coatings, Structural Repair

### RE: Pittsburgh bridge collapse

2
https://bridgereports.com/1456104

Name: FORBES AVENUE over 9 MILE RUN & FERN HOLLOW
Structure number: 000000000002410
Old structure number: 027301000030330 (from 1992 edition)
Location: 301033 NEAR S BRADDOCK AV

Latest Available Inspection: September 2017
Good/Fair/Poor Condition: Poor
Average daily traffic: 14,500 [as of 2005]
Truck traffic: 7% of total traffic
Deck condition: Fair [5 out of 9]
Superstructure condition: Poor [4 out of 9]
Substructure condition: Satisfactory [6 out of 9]
Structural appraisal: Meets minimum tolerable limits to be left in place as is [4]
Deck geometry appraisal: Basically intolerable requiring high priority of corrrective action [3]
Water adequacy appraisal: Superior to present desirable criteria [9]
Roadway alignment appraisal: Better than present minimum criteria [7]
Channel protection: There are no noticeable or noteworthy deficiencies which affect the condition of the channel. [9]
Scour condition: Bridge foundations (including piles) on dry land well above flood water elevations. [9]
Sufficiency rating: 18.7
Recommended work: Bridge rehabilitation because of general structure deterioration or inadequate strength. [35]
Estimated cost of work: $1,522,000 Bradley Wilder, P.E. Construction P.E. (KY), MBA Bridge Rehab, Coatings, Structural Repair ### RE: Pittsburgh bridge collapse Hard to see on Google, but it looks like a rigid K-frame. Bradley Wilder, P.E. Construction P.E. (KY), MBA Bridge Rehab, Coatings, Structural Repair ### RE: Pittsburgh bridge collapse Condition rated as poor since 2011. [/sarc] Nothing to see here. [/end sarc] ### RE: Pittsburgh bridge collapse Gathering some data... Story says there was an articulated city bus on the bridge and at least 4 vehicles. There was at least some snow on the bridge. As of the May 2019 street view photo, the bridge was posted at 26 TONS. From Wikipedia, PAAC has New Flyer D60LFR buses, which have a 41,500-43,700 curb weight and New Flyer XD60 Xcelsiors which have a curb weight of 39,000-45,500 lb. Bradley Wilder, P.E. Construction P.E. (KY), MBA Bridge Rehab, Coatings, Structural Repair ### RE: Pittsburgh bridge collapse I grew up 5 or six miles from that bridge. I remember its predecessor, but I had to search to refresh my memory of the current structure, which agrees with the picture above. Google street view shows it posted with a 26 ton weight limit. Also, for what it's worth, from Wednesday night into yesterday morning it was awfully cold here. Minus 12 at 7:30 a.m. where I was. ### RE: Pittsburgh bridge collapse Pic from December 2018 from Twitter @gpk320 Bradley Wilder, P.E. Construction P.E. (KY), MBA Bridge Rehab, Coatings, Structural Repair ### RE: Pittsburgh bridge collapse It looks like they tried a band aid fix for that. But not a large enough band aid if that member goes into compression. With a few inches of snow and the bus, that was well over the posted weight limit. Interesting to see how this might affect public transportation policy if our vehicles are too large for our aging infrastructure. ### RE: Pittsburgh bridge collapse It looks like the east bent is missing the lower cross bracing compared to the west end. It's a bit blurry from the google street view but its still clearly missing. The resolution is too poor to see if the cables are still there. The images are from 2020, 2 years after the pic of the cables was posted. ### RE: Pittsburgh bridge collapse bradw1128 Thanks for the inspection report, I was just watching a video of Mayor Ed Gainy (sp) speaking to reporters as he was given false information on that inspection date, he was told September of 2021. First he said he thought it was about 2 yrs ago. https://www.youtube.com/watch?v=Nl6LgfLEJCU - time stamp at around 15:00 in. It's amazing timing that 3 days ago Biden planned this visit to Pittsburgh today. ### RE: Pittsburgh bridge collapse There was a snow event on Jan 16-17 that put down about 7" in that area, but this morning's snow was an inch, or less. ### RE: Pittsburgh bridge collapse Looks like maybe the city was considering repairs as of 2019: From the 2019 capital budget https://apps.pittsburghpa.gov/redtail/images/4499_... Page 172: Legislative & Contractual Committments [OMB] Maintenance and Improvements to Forbes Ave Bridge$ 3,000,000.00 $- 4 I can't tell if it was ever actually funded. And from a draft STIP project page, a longer term replacement plan: https://www.spcregion.org/wp-content/uploads/2021/... Page 45: Allegheny Forbes Ave Bridge over Fern Hollow*$6,892,000 7301 Long‐Term (2033‐2045)
Bridge restoration/replacement on Forbes Avenue
Bridge over Fern Hollow in the City of Pittsburgh,
Allegheny County; Project sponsor is City of
Pittsburgh
Bridge Reconstruction 20192023

Construction P.E. (KY), MBA
Bridge Rehab, Coatings, Structural Repair

### RE: Pittsburgh bridge collapse

A more interesting question, "How much more of that stuff is out there?" I'm glad there were no fatalities.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

### RE: Pittsburgh bridge collapse

dik, as I drive around Ohio and surrounding states, I would have to say that it is extensive. The levels of corrosion and failing concrete is spooky. 90% of this issues in this area are a direct result of the application of de-icing materials, be it salt, calcium chloride, brine, etc. At some point, we need to wake up and stop the direct application of these chemicals to our bridge decks. Galvanizing and epoxy paint can only do so much. My state DOT uses and average of 600,000 tons of salt per year. This does not include all of the cities, counties, townships, etc. that also clear roads.

### RE: Pittsburgh bridge collapse

I was thinking of that condo unit in Florida that collapsed, killing nearly 100. I suspect a lot of the problem was poor design and lack of maintenance. Things will not get better without 'fixing' things.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

### RE: Pittsburgh bridge collapse

This represents the 2019 routine inspection and 2020 fracture critical and special inspection. All seemed to be on a September schedule. There likely was a +/- September 2021 inspection after this data was uploaded.

There were fracture critical and special inspections on a 12 month frequency.

STATE_CODE_001 PA
STRUCTURE_NUMBER_008 000000000002410
RECORD_TYPE_005A on
ROUTE_PREFIX_005B city street
SERVICE_LEVEL_005C mainline
ROUTE_NUMBER_005D n/a
DIRECTION_005E n/a
HIGHWAY_DISTRICT_002 11
COUNTY_CODE_003 Allegheny
PLACE_CODE_004 61000
FEATURES_DESC_006A
CRITICAL_FACILITY_006B
FACILITY_CARRIED_007 'FORBES AVENUE'
LOCATION_009 '301033 NEAR S BRADDOCK AV'
MIN_VERT_CLR_010 99.99
KILOPOINT_011 0
BASE_HWY_NETWORK_012 1
LRS_INV_ROUTE_013A
SUBROUTE_NO_013B
LAT_016 40262229
LONG_017 79540120
DETOUR_KILOS_019 5
TOLL_020
MAINTENANCE_021 City or Municipal Highway Agency
OWNER_022 City or Municipal Highway Agency

FUNCTIONAL_CLASS_026 other principal arterial
YEAR_BUILT_027 1970
TRAFFIC_LANES_ON_028A 4
TRAFFIC_LANES_UND_028B 0
APPR_WIDTH_MT_032 15.2
MEDIAN_CODE_033 0
DEGREES_SKEW_034 0
STRUCTURE_FLARED_035 0
RAILINGS_036A 0
TRANSITIONS_036B 0
APPR_RAIL_036C 0
APPR_RAIL_END_036D 0
HISTORY_037 Bridge is not eligible for the National Register of Historic Places
NAV_VERT_CLR_MT_039 0
NAV_HORR_CLR_MT_040 0
SERVICE_ON_042A highway-pedestrian
SERVICE_UND_042B waterway
STRUCTURE_KIND_043A steel continuous
STRUCTURE_TYPE_043B frame
APPR_KIND_044A n/a
APPR_TYPE_044B n/a
MAIN_UNIT_SPANS_045 3
APPR_SPANS_046 0
HORR_CLR_MT_047 15.2
MAX_SPAN_LEN_MT_048 50.6
STRUCTURE_LEN_MT_049 136.2
LEFT_CURB_MT_050A 2.1
RIGHT_CURB_MT_050B 2.1
DECK_WIDTH_MT_052 19.5
VERT_CLR_OVER_MT_053 99.99
VERT_CLR_UND_REF_054A N
VERT_CLR_UND_054B 0
LAT_UND_REF_055A N
LAT_UND_MT_055B 0
LEFT_LAT_UND_MT_056 0
DECK_COND_058 poor
SUPERSTRUCTURE_COND_059 poor
SUBSTRUCTURE_COND_060 satisfactory
CHANNEL_COND_061 There are no noticeable or noteworthy deficiencies which affect the condition of the channel
CULVERT_COND_062 n/a
OPERATING_RATING_064 29.9 metric tons
INVENTORY_RATING_066 17.2 metric tons
STRUCTURAL_EVAL_067 Meets minimum tolerable limits to be left in place as is
DECK_GEOMETRY_EVAL_068 Basically intolerable requiring high priority of corrective action
UNDCLRENCE_EVAL_069 n/a
POSTING_EVAL_070 10.0 - 19.9% below (relationship of operating rating to maximum legal load)
WATERWAY_EVAL_071 Superior to present desirable criteria
APPR_ROAD_EVAL_072 Meets minimum tolerable limits to be left in place as is
WORK_PROPOSED_075A Bridge rehabilitation because of general structure deterioration or inadequate strength.
WORK_DONE_BY_075B Work to be done by owner's forces
IMP_LEN_MT_076 136
DATE_OF_INSPECT_090 Sep-19
INSPECT_FREQ_MONTHS_091 24
FRACTURE_092A Yes - 12 months
UNDWATER_LOOK_SEE_092B N
SPEC_INSPECT_092C Yes - 12 months
FRACTURE_LAST_DATE_093A Sep-20
UNDWATER_LAST_DATE_093B
SPEC_LAST_DATE_093C Sep-20
BRIDGE_IMP_COST_094 113,000
TOTAL_IMP_COST_096 1,522,000
YEAR_OF_IMP_097
OTHER_STATE_CODE_098A
OTHER_STATE_PCNT_098B 0
OTHR_STATE_STRUC_NO_099
STRAHNET_HIGHWAY_100 0
PARALLEL_STRUCTURE_101 N
TRAFFIC_DIRECTION_102 2
TEMP_STRUCTURE_103
HIGHWAY_SYSTEM_104 Inventory Route is on the NHS
FEDERAL_LANDS_105 n/a
YEAR_RECONSTRUCTED_106 0
DECK_STRUCTURE_TYPE_107 Concrete Cast-in-Place
SURFACE_TYPE_108A Bituminous
MEMBRANE_TYPE_108B none
DECK_PROTECTION_108C none
NATIONAL_NETWORK_110 The inventory route is not part of the national network for trucks
PIER_PROTECTION_111
BRIDGE_LEN_IND_112 yes
SCOUR_CRITICAL_113 Bridge foundations determined to be stable for calculated scour conditions; scour within limits of footing or piles
MIN_NAV_CLR_MT_116 0
FED_AGENCY N
SUBMITTED_BY 42
BRIDGE_CONDITION P
LOWEST_RATING 4
DECK_AREA 2655.9

Construction P.E. (KY), MBA
Bridge Rehab, Coatings, Structural Repair

### RE: Pittsburgh bridge collapse

While salt/chlorine is bad for bridges, I do think a part of the issue here is lack of maintenance over the year. Relatively speaking the bridge being 50 years old should not be in such a poor condition for so long (since 2011?). We use probably just as much salt here in Toronto and of all the road bridges I inspected past few year I do not recall seeing one with an entire bracing member corroded through.

### RE: Pittsburgh bridge collapse

Dik - I'd wager every major city in a snowy climate has at least 1 similar situation. when i lived in pittsburgh, there was an old (80 years old) concrete bridge i remember that had such bad spalling problems they ended up building a deck over the road below to catch the falling debris. they finally replaced the concrete bridge a few years back but that catch deck was up for 10 or 15 years.

In our small town in Maine the DOT has been trying to replace an 80 year old truss bridge since 2017 but has been stymied by court efforts from historic preservation groups that want it preserved and rehabbed rather than replaced. a beautiful bridge for sure, but the prolonged court proceedings has meant that neither replacement nor repairs have been made at all and the bridge was posted to 10 tons a couple months ago.

https://bridgehunter.com/me/cumberland/2016/

I'll be reconsidering my driving routes the rest of winter.

### RE: Pittsburgh bridge collapse

#### Quote (Post Gazette)

The bridge collapsed as the city prepared for a visit from President Joe Biden, who is scheduled to speak about infrastructure Friday afternoon at Mill 19 in Hazelwood. Multiple officials said the collapse illustrated the need for infrastructure investment.

Glad nobody was seriously hurt, but truly this bridge had a sense of humor.

### RE: Pittsburgh bridge collapse

Karma...

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

### RE: Pittsburgh bridge collapse

Here is the element level data.
https://infobridge.fhwa.dot.gov/Data/BridgeDetail/...

All 4 steel columns were at condition state 4 (severe)
2 of 4 movable bearings were at CS3 (poor)

I would expect that having a CS4 condition on a primary structural element like that would have triggered a more detailed structural review. I don't know the policies in PA though or how city-owned bridges might follow it.

Construction P.E. (KY), MBA
Bridge Rehab, Coatings, Structural Repair

### RE: Pittsburgh bridge collapse

Old timber truss bridges are neat...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

### RE: Pittsburgh bridge collapse

How are the reduced posted weight limits determined in these scenarios? Is 26 tons chosen through detailed structural analyses assuming certain failed members or is it a judgement call based on the types of vehicles that they want to prohibit?

### RE: Pittsburgh bridge collapse

#### Quote (bradw1128 (Civil/Environmental)28 Jan 22 14:02)

It makes one wonder how they decided that the cross member required supplemental measures but the column didn't.

### RE: Pittsburgh bridge collapse

#### Quote (timeforchili)

How are the reduced posted weight limits determined in these scenarios? Is 26 tons chosen through detailed structural analyses assuming certain failed members or is it a judgement call based on the types of vehicles that they want to prohibit?

Someone would have had to completed a structural evaluation (inspection and analysis) to determine the load posting. They would have modelled failed connections, section loss, verified material strengths, etc.

### RE: Pittsburgh bridge collapse

I am not sure how we got to a point in the country were a bridge in a local municipality needs to be paid for by the federal government. I can see perhaps federal involvement on bridges in the interstate highway system. I think waiting for the benevolent hand of the feds to dole out money is never going to work. The local agency should be responsible. If they need to raise taxes or utilize tolls, so be it.

### RE: Pittsburgh bridge collapse

#### Quote (timeforchili)

How are the reduced posted weight limits determined in these scenarios? Is 26 tons chosen through detailed structural analyses assuming certain failed members or is it a judgement call based on the types of vehicles that they want to prohibit?

It goes through a certain structural analysis program for the load rating of bridges, in accordance with the FHWA and state DOTs.

### RE: Pittsburgh bridge collapse

3
Bill Watterson is the best!

### RE: Pittsburgh bridge collapse

2
Well the feds aren't going to pay for it anyway because Congress can't get out of their own way, and the locals aren't going to raise taxes because then people might actually care about local elections and replace them.

So I think deficient bridges should simply be closed. Don't let people drive across them. Eventually people will be pleading the local government to take their money to make the repairs that are needed...or we'll all just wait in traffic for 2 hours to get to the grocery store. Either way, we get what we deserve.

### RE: Pittsburgh bridge collapse

4
Without getting political, there's a real downside to Reaganomics; this is the beginning.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

### RE: Pittsburgh bridge collapse

#### Quote (phamEng)

So I think deficient bridges should simply be closed. Don't let people drive across them.

Especially non-redundant ones.

### RE: Pittsburgh bridge collapse

2

#### Quote:

So I think deficient bridges should simply be closed. Don't let people drive across them.

As I often point out on disaster posts, this is how the existing process is supposed to work. Unfortunately nobody stateside seems interested in holding the muni engineers accountable for failing to close infrastructure before disasters like this, instead they spend hours blaming politics for lack of funding. Sorry not sorry but an engineer belongs in jail for this.

### RE: Pittsburgh bridge collapse

#### Quote (bridges that are owned by railroads in Pittsburgh are not maintained at the expense of the City.)

I would venture to say that today railroads only maintain bridges carrying their tracks. In NYC, there are a fair amount of bridges - rail and vehicular - that were constructed by the railroads in the 19th & early part of the 20th Centuries. As the railroads starting going bankrupt after the war the ownership of the vehicular bridges was transferred to the city and state, mostly in the 50's/60's. Even in the 80's to get plans for these bridges we had to go to the railroad for them. A bit of history.

### RE: Pittsburgh bridge collapse

I doubt there were many railroads that included vehicular pathways on their railroad bridges. Safety comes to mind. Plus: why would they do that?

Not saying it didn't happen, but I see it as quite rare.

However.

Transit rail is another thing. I do not view that as "railroad". For example, they are generally not common carrier. There was, for example, transit rail on the San Francisco Bay Bridge. I do wonder what, if anything, that carrier paid the "authority" for usage.

By now, most/all transit rail has been rolled into government ownership/support. So they wouldn't appear to be sources of more funding for bridge maintenance.

However.

In this case, we're talking about Pittsburgh, and its 400+ bridges. Separating transit rail from common-carrier rail, I wonder which bridges handling the latter do also support vehicular traffic.

spsalso

### RE: Pittsburgh bridge collapse

PA also has their famous turnpike. About ten years ago my wife wandered onto the NE extension on a trip from DC to NY. I remember marveling from the passenger seat at the nice new road and a sign that must've been 10' tall bragging about ~$100M in construction, we thought PA was pretty ok until she had to pay$70 in tolls for her commuter car.

### RE: Pittsburgh bridge collapse

#### Quote (I doubt there were many railroads that included vehicular pathways on their railroad bridges. Safety comes to mind. Plus: why would they do that?)

Let me clarify: I wasn't talking about a bridge with tracks and vehicles side by side on the same structure. If a grade separation was required, the railroad was responsible for the bridge.

#### Quote (\$70 in tolls)

That's two round trips on the extension, without the EZ-Pass discount.

### RE: Pittsburgh bridge collapse

#### Quote (bridgebuster)

Let me clarify: I wasn't talking about a bridge with tracks and vehicles side by side on the same structure. If a grade separation was required, the railroad was responsible for the bridge

Oh. If there was an existing railroad, and there was to be constructed a road with a grade separation over the railroad, the railroad was responsible for the bridge?

I would have thought whoever arrived at the location second pays for the crossing. And that if one party wanted an improvement in that crossing (changing an at-grade crossing to a separation), that party would pay for it.

spsalso

### RE: Pittsburgh bridge collapse

Perhaps, but the railroad operators receives benefits as well, if nothing else than not having to maintain a grade crossing including gates and lights to say nothing of the infrastructure along the tracks required because of the crossing. And then there's the fact that the trains no longer have to slow down nor sound their horn (to the discomfort of the nearby residents) as they approach and pass the grade-level crossing. In our city, they've constructed three underpasses, replacing all but one grade-level crossing, on the mainline track (a double track shared by Amtrak, Metrolink and the freight operators).

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

### RE: Pittsburgh bridge collapse

Here is an interesting discussion of funding for Riverside County grade separations:

A quick read shows little railroad money included. The various physical structures (bridges, piers, abutments) involved would appear to be government owned and maintained.

spsalso

### RE: Pittsburgh bridge collapse

#### Quote (Optical98)

It's amazing timing that 3 days ago Biden planned this visit to Pittsburgh today.

I am amazed that none of the very smart engineers around here have not made that cause and effect linkage yet.

(That collapsed section is in a deeper state than previously you could even say.)

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

### RE: Pittsburgh bridge collapse

yeah...and if you squint really hard, turn your monitor upside down, and then look out of the window 6 times, the bridge even forms the shape of a Q on the ground...

### RE: Pittsburgh bridge collapse

Thanks!

Bridges look much bigger when they're on the ground.

spsalso

### RE: Pittsburgh bridge collapse

NTSB release.

This space intentionally left blank.

### RE: Pittsburgh bridge collapse

#### Quote (Nukeman948)

NTSB release.

Time for the news agencies to start incorrectly defining "fracture critical" to the public.

### RE: Pittsburgh bridge collapse

Design is moving along; construction to begin in April. There was an article in Roads and Bridges today.

### RE: Pittsburgh bridge collapse

If I may summarise, as the bus is approaching the east end of the bridge (just prior to the east ends imminant collapse), the west end has already collapsed (behind the bus).

### RE: Pittsburgh bridge collapse

Lawsuits ... make it official that this incident did indeed happen in the USA.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

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