Squibb Park Brooklyn NYC - Zoli designed pedestrian suspension bridge failure - pride comes before the collapse!

Submitted by Jeff Buster on Mon, 01/04/2016 - 17:03.

 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.   
 
 
 
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. Squibb bridge image from brooklyn heights blog.JPG
 
2.  “tree”  like towers are not sufficiently rigid or massive to act as gravity anchors – compare to cable anchorages of the Golden Gate Bridge
Squibb bridge image underside of anchorage from max-carr blogspot.JPG
 
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 ConzettFirst travertina bridge Jurg Conzett.JPG
 
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

 

line-height:115%;Times New Roman"">A Critical Look at Bridge Design Practice:                                     March 24, 2014
Beyond Material Efficiency                                                             
line-height:115%;Times New Roman"">3:30pm – 4:30pm
                                                                                                                                                      131 DeBartolo
Theodore P. Zoli, P.E.
National Bridge Chief Engineer, HNTB
Minimizing materials, which is at the core of the way we teach and practice bridge design, is becoming less relevant.   Fabrication, transportation, and erection dominate the costs of modern bridges, and offer new opportunities for innovation.  Given these new sets of constraints, there is great potential to create much safer, more robust structural systems than before. These ideas are explored through a number of recently built structures. 
Ted Zoli is one of the bridge engineering and design industry’s most recognized figures, the subject of profiles in magazines such as Esquire and Popular Mechanics, and the first structural engineer to receive the prestigious MacArthur Foundation Genius Award. To his leadership position as HNTB’s national bridge chief engineer, Zoli brings international acclaim as the innovator behind numerous bridges — long span, movable, pedestrian and rail. Among his most notable projects are the cable-stayed Leonard P. Zakim Bunkerhill Bridge in Boston, the curved cable-stayed Bob Kerrey Pedestrian Bridge in Omaha, Neb. and the Lake Champlain Bridge between New York and Vermont. Ted Zoli’s areas of expertise range from network tied arch bridges, bridges in disaster relief and terrorism protection to other unique bridges. With more than two decades at HNTB, Zoli's noted accomplishments include Blennerhassett Island Bridge over the Ohio River and the 396-foot-long Squibb Park Bridge in Brooklyn Heights, N.Y. Zoli is also using a grant from the MacArthur Foundation to develop a lightweight, ultra-portable pedestrian rope bridge for rural areas, as well as a lightweight hypar semi-permanent shelter that is an adaptation of boat hull technology. In terrorism prevention, his innovations have included protective measures for the main cables and hangers of suspension bridges incorporating advanced composite materials.  Zoli is recognized throughout the world as an expert in creating safer, less expensive, more sustainable and better-performing bridges of all kinds.
 
 
This is what the document looks like in its Word format:
 

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!