WPCNR IN TRANSIT. By John F. Bailey. August 3, 2007: A New York State Transportation spokesperson reported to WPCNR Thursday that the Department of Transportation had no plans to reinspect the Tappan Zee Bridge in the wake of the Minneapolis I-35 Bridge Collapse Wednesday.

The spokesman said work on the outer right two lanes of the Tappan Zee Bridge in both directions would begin at the end of August and would include replacement of steel members that the new deck would rest on. He added that as more information on what caused the I-35 bridge to fail becomes known, all bridges in the state of similar construction and materials would be inspected for the defects as they are defined. Here is WPCNR’s interview with Ramesh Mehta, speaking for the Department of Transportation:

The Tappan Zee Bridge.

WPCNR conducted an interview with Ramesh Mehte spokesman for the New York Department of Transportation late Thursday afternoon. Here is how it went:

 

WPCNR: Your’e redecking it..you started that in the spring.

Mr. Mehte: Actually what we have been doing so far is the prefabrication of the material, the steel and the concrete. At the site we will be starting the work at the end of this month. The steel is fabricated and they attach the concrete deck to the steel.

WPCNR: So the redecking includes replacing some of the steel support (of the deck)?

Mr. Mehte: Some of the components of the steel will be replaced, yes.

WPCNR: When is it estimated the redecking will be complete?

Mr. Mehte: The end of next year (December, 2008)

WPCNR – How much life will this deck give the present bridge?

Mr. Mehte: The new decking wherever we are replacing it should give 40 to 50 years (life to the bridge).

WPCNR: How are the DOT engineers reacting to the Minneapolis Bridge Collapse – are they thinking of reinspecting the Tappan Zee Bridge again throgoughly just to make sure in a more intensive manner? What is their reaction to that?

Mr. Mehte: We still don’t know what was the mode of failure of that bridge in Minnesota. We do not know exactly how it happened…the type of members, the type of connections. Once we get that detail, if we have similar bridges in New York State or this region we will go and inspect them again. We are trying to find out more information what materials it was which actually prompted the failure of that bridge.

It was a steel arch bridge, I do not know exactly. The TZB is a completely riveted structure. I do not know if the Minnesota Bridge was a riveted structure or a vended structure. Vended structures can have their own sets of problems. So we are still trying to get the details. We are trying to say what was the reason that it failed then we will identify all the bridges in New York State. We’ll all be working together to see what type of additional inspection we should be doing so we do not compromise the structures.

WPCNR: The Tappan Zee Bridge Deck replacement, it is a partial replacement?

Mr. Mehte: Yes, it is only the right two lanes in each direction. Some of the bridge deck we have already replaced in the past.

WPCNR: Is it fair to say the Tappan Zee Bridge is going to remain there regardless of what replacement is deemed necessary?

Mr. Mehte:  Yes, but the decision of replacement, whether we have to retain this bridge, or we have to have a major rehab of the bridge, that will come at the end of 2008. In meantime, whatever is necessary to keep the bridge going. If we have to replace the bridge we will replace the bridge if that is the decision. In the meantime we have to continue to invest money in this bridge to make sure the bridge is to remain safe for the passage of the people.

WPCNR: At this point there’s no plan to immediately go over the Tappan Zee Bridge with a fine tooth comb, so to speak?

Mr. Mehte: Correct. That’s right.

WPCNR: When was the Tappan Zee Bridge last inspected?

Mr. Mehte:  It was  inspected last year from May to November 2006.

WPCNR: Was that when you decided to replace the deck (the upcoming rehab)?

Mr. Mehte: No,  we knew those items which require the rehab work. This project of $147 Million was let in December of 2005, and we awarded the contract to the contractor in August 1, 2006. We had already initiated that project. It takes some time to design the whole thing, the lead fitting, and awarding the contracts. Some of the deficiencies observed during the 2006 inspection we knew it and it was already covered in this contract. When we get some more details (on the Minnesota bridge) in the next few days, we will make plans to go and do the inspection.

WPCNR: The work being done now includes some steel members?

Mr. Mehta: Some steel members and the top deck which is the riding surface.

WPCNR: The underpinnings of the bridge, the uprights, no work is being done?

Mr. Mehta: Very little work. Only isolated members. Otherwise it is in good condition.

 

WPCNR’S THE DAILY BAILEY.  News & Comment By John F. Bailey. August 2, 2007 UPDATED 2:31 PM EDT: The shocking, unexpected descent of the I-35 West Bridge (in Minneapolis, Minnesota) into the Mississippi River yesterday – which began life in 1967 – eight years after the Tappan Zee Bridge opened – should be a sobering wake-up fall to the Department of Transportation, the MTA and the New York State Thruway Authority and the Port of New York Authority bridgemasters, too — as well as county leaders in Rockland and Westchester County.

 

How Safe Is the Tappan Zee Bridge Now?

Donna Greene, Assistant Communications Director for Westchester County gave County Executive Andy Spano’s reaction to the Minneapolis collapse in a statement: “I have been assured by the Thruway Authority that the millions of dollars that have been spent on the bridge ensure the safety of it. However a long-term solution obviously is needed.” Greene assured WPCNR that “The county executive, of course, will stay on top of it through his many conversations with key state officials, his TZB Task Force and his work with  NYMTC (the NY Metropolitan Transportation Council). 

The state obviously needs to make a decision on the future of the Tappan Zee Bridge and soon and stop fumbling the political football of how we replace or augment the bridge. They need to replace that political game by getting a solid grasp on the question: how good is the bridge now? And how adequate will be the deck repairs that began this spring? And, how safe is it anyway? 

The makeshift repairs on the TZB have been going on for years. How long will the new TZB deck last? How long can it be expected to support traffic while a replacement is built?  What has to be done now to buttress the present structure? Does the structure need to be reinforced?  And does the present support structures need work? These are questions the DOT needs to answer in light of the Minneapolis bridge failure.  We the trusting public always assume the professionals know their bridges.

The DOT is currently replacing the deck over a two-year schedule that will replace 40% of the entire deck. This was what Minnesota workers were doing on the Minneapolis Bridge that collapsed yesterday, after declaring the steel support structure fatigued but having no cracks, according to news reports. So what happened? This will be very instructive.

According to the New York State Thruway news release this spring on the deck replacement, “The deck replacement project, expected to take place over a two-year phased schedule, will replace approximately 40% of the entire deck. This portion of the deck, including the west end of the bridge and the main truss, is in the most need of work and is therefore the most critical to replace. In previous years, the Authority replaced half the length of the center lane of the causeway and the entire east truss deck.”

Years ago a pal and I were heading across the George Washington Bridge on our way West. I remarked to Paul, noting the age of the George Washington Bridge (1931), how do they know this is safe? Paul said, “they inspect it.” We both laughed uneasily. But does the Minneapolis collapse say something about overall structure soundness the engineers did not know? Can it all go at once?

The Mianus River Bridge Collapse Revisited

A reporter who covered the Mianus river bridge collapse in   Greenwhich, Connecticut on the night of June 28, 1983, recalled that when that bridge collapsed it was a section of the bridge that fell due to a joints problem. She expressed interest that an entire structure collapsed in the Minneapolis case.

The Mianus River Bridge, Greenwich, Connecticut.

More sobering is that the engineering firm was not found to be at fault in that accident and the State of Connecticut eventually settled suits with the three persons killed in that collapse. According to United Press International dispatch of May 25, 1984, the state of Connecticut did not distribute Federal regulatory guidelines that could have made state inspectors “aware” of problems leading to the collapse.

The National Transportation Safety Board said that the manuals “remained in supervisors’ bookcases and were not available to maintenance inspectors,” in a preliminary report. UPI, in addition pointed out that the NTSB preliminary report “drawn from four days of testimony by engineers, officials and witnesses,” that  “the  (Connecticut) state officials were cited for not alerting inspectors to the inspection procedures for pin-and- hanger structures and for not maintaining an inspection schedule.”

Well, persons who use the Tappan Zee Bridge every day have to be asking themselves how good are the inspections of the TZB? We have had a lot of suggestions that it needs replacing. Why does it need replacing? And how worn out is it?

Should shore-up supports be constructed right away on the suspended portion of the TZB? This is no longer a question of what shall we do to replace the bridge? In light of the Minneapolis bridge failure, the analysis of the Tappan Zee structure has to address the question of how safe is it now? And why is it safe? And how can we be sure it’s safe?

Previously, the information on replacing the Tappan Zee Bridge was not one of safety. The Tappan Zee Bridge website says the bridge is inadequate for present traffic needs, reporting, “More than 135,000 vehicles cross the 3.1 mile Tappan Zee Bridge every day, with volumes as high as 170,000 vehicles daily. If nothing is done to relieve congestion in the I-287 corridor between Suffern and Port Chester, by 2030 traffic crossing the bridge will increase to 200,000 cars per day. Travel times are expected to grow significantly.”

 

The Tappan Zee Bridge website (www.tzbsite.com) acknowledges the old TZB has problems, to wit: “The Bridge does not meet current seismic criteria… Although the bridge is safe, due in large part to a rigorous program of maintenance and inspection, it is nearing the end of its service life.”

The website elaborates on the bridge “problems,” emphatically stating: “Yes, the Tappan Zee Bridge is safe. The New York State Thruway Authority operates a regular program of scheduled maintenance designed specifically to ensure the bridge is safe for travel. The bridge also receives a detailed inspection every two years by qualified engineers.”

The Westchester County Department of Communciations  in their statement above did not address whether the county was going to ask for an update of bridge conditions in light of the totally unexpected failure of Minnesota’s “safe” bridge – declared safe with a bit of “fatigue” last year, according to media reports.

More than ever the rebuilding of the bridge has to stop becoming a political issue and become a safety issue.

If it were up to me I’d say the present bridge has to be repaired extensively immediately from a support standpoint. Admittedly, this is not the same structure bridge that fell in Minneapolis. But how safe is it, anyway? And we are not talking about the lack of breakdown lanes, the movable media barrier or the lack of speed enforcement on the bridge. (That’s another column).

Can you imagine the disaster if this bridge collapsed? In loss of life immediately? And long term – the commuting nightmare as all traffic diverted to Newburgh Beacon Bridge, the Bear Mountain Bridge and the  George Washington Bridge?

As of this hour the New York State Thruway Office of Public Affairs has not responded to WPCNR questions about their Tappan Zee Bridge safety program effectiveness, whether they plan to take a more detailed look at the bridge, and how long the bridge will last after the deck repair.

I think the Thruway engineers have to be having sobering thoughts this morning.

I would.

And I’d be going over that bridge with a fine tooth comb.

Right now.