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Squibb Park Brooklyn NYC - Zoli designed pedestrian suspension bridge failure - pride comes before the collapse!Submitted by Jeff Buster on Mon, 01/04/2016 - 16:03.
A Friend of mine who lives in NYC sent me a link to the 12.24.15 New York Times article reporting on the continuing closure of the Ted Zoli designed/engineered pedestrian bridge in Squibb Park, Brooklyn, New York City. Reporter Lisa W. Foderaro explains that the bridge was constructed and opened in 2013, the bridge was closed without explanation in 2014, and remained closed in 2015. No one will say why the bridge is closed. No one is talking. Too embarrassing.
When the bridge was opened Mr. Zoli explained that his design inspiration was the “trail” style suspension bridge.
You know, something similar to the catenary cable, end anchored, pure suspension bridge that is used all around the world.
Image credit See more trail bridges here.
But Mr. Zoli’s bridge is different from a “trail” bridge because the Squibb bridge has a compressive deck and is not end-anchored in tension.
Mr. Zoli said the Squibb Bridge was meant to bounce and rock – for fun. You can see lateral deck bending in the image below. Note also that right hand side of walkway is lower (10"?) than the left side of the walkway. Not good. The walkway deck is in the process of overturning.
In the image below chair binders or come-a-longs are visible on the deck - used in post-slosure effort to "straighten" the deck. Image from NYTimes.
Think about it, if a bridge moves, there will be wear and tear. If there is wear, the bridge dimensions will change asymmetrically. So, intentionally designing a bridge that bounces and rocks is like designing a car with steering that doesn’t go straight – for “fun”! The Tacoma Narrows Bridge swayed and moved too – collapsing in a catastrophic wind powered harmonic .
The ends of the Squibb bridge are not anchored in tension to the concrete tree-like towers. This is obvious because:
1. The bridge sections are not in alignment but zig zag – so no tension or compression can be transferred between the (2) independent deck “suspension” sections.
2. “tree” like towers are not sufficiently rigid or massive to act as gravity anchors – compare to cable anchorages of the Golden Gate Bridge
Instead the tension cables at the bottom of the Squibb bridge are put into tension by compression on the flat deck. But the deck is not a monolithic compressive element but rather a sectional compressive element. The bridge sections between the tree towers are trusses – with a lower tension chord and an upper compressive chord.
What should have been designed is this below: First travertina bridge Jurg Conzett
Who will say it? The Squibb Bridge design is flawed, The bridge needs to be removed.
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closed Squibb Bridge engineer Zoli provides CV
The following Word document can be found at this link: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwi-jtiNmLHKAhVF4SYKHVILCPwQFggcMAA&url=https%3A%2F%2Fceees.nd.edu%2Fseminars-field-trips%2FZoli_final.docx&usg=AFQjCNFMOOGP1JDLFWRObfsfZW6S-Ih2FQ&sig2=TCQE6Qknz1k_DffqVQtvRg&bvm=bv.112064104,d.eWE
Beyond Material Efficiency line-height:115%;Times New Roman"">3:30pm – 4:30pm
131 DeBartolo
National Bridge Chief Engineer, HNTB
Lawsuit filed today vs Zoli re: Squibb bridge failure
Read the lawsuit here at gothamist.com
Where are the engineering ideas/suggestions for resolving this bridge failure?
Big opportunity to show your stuff here....
The suit is brought by the City of New York against HNTB...two paragraphs from the suit sum it up...
"24. HNTB breached the Contract by failing to exercise due care in its performance,and breached the terms and conditions of the Contract by reason of its defective design, all of which resulted in a structurally unsound, faulty and defective Bridge,requiring its closure and repair.
25. As a direct result of HNTB's aforesaid breaches of the contract, BBP has been damaged in an amount to be determined at trial, but not less than 3 million."
Squibb Bridge "public-private-partnership" park scam
There are at least two things of interest in this image taken March 24, 2016: 1. On the top of the pedestrian deck the slack rachet lever chain hoists which were installed diagonally across the deck with the intention of lifting one side of the walkway relative to the other.... 2. On the underside of the deck tension rods are visible that are not straight - meaning they are not in tension (the far side of the deck is being pushed up).
Also of interest is the building that is proceeding while the "public park" bridge lies un-usable. This development is a new model for funding public parks in NYC. Perhaps this is really the big story here - not that Mr. Zoll has made engineering mistakes - but that we have been sold the "public-private-partnership" scam.
The apartments are being erected for private profit, while the public amenity which the private profit is supposed to build and maintain has gone off the rails.
NYC better wake up!