Report and Gallery

NEWS: 2015 HNTB Report Finds Bridge is Restorable!

PROVIDES EVIDENCE THAT RESTORING ORIGINAL BRIDGE WOULD SAVE MILLIONS

(Editor’s Note: This PedBridge.com Article was Published in November 2020)

The bridge can be restored according to a 2015 report by HNTB, the highly respected engineering and architecture firm, and at a savings to boot, it appears. The firm’s report included methods for replacing piers and a total cost estimate. (Note: The estimate was for the proposed two-deck version of the bridge—restoring the bridge as-is could save millions more; see further below.) The report contains a great deal of technical information and should be examined closely by those interested from beginning to end. You can download the PDF further below.

Below: Methods for addressing the bridge piers (excerpts)

Below: HNTB’s preliminary estimate of probable cost. Notice that, even with upper and lower decking, the estimated total cost was some millions less than the estimated cost of the currently proposed replacement bridge (which, at about $27 million dollars, still lacks shade, benches, and lighting funds). If the bridge were to be restored as-is (with only lower decking), it would likely be a considerably greater financial savings. How much less? Read on for more info…

If you notice the term “Demolition,” it is because the firm recommended demolishing specific areas of the bridge, such as “the first span at the west bank of the river”; “It is proposed that these areas be demolished and replaced with new structure” (see page 5-2 of the report).

Looking at the report, a local engineer provided the following conversational opinion about restoring the bridge, proceeding on the basis of the report’s numbers (this was offered in a private communication):

If you take out the unnecessary work required for bicycle access to upper deck, upgrade lower deck only, and leave in necessary work and basic lighting you come up with a total cost of approx. the following (using their numbers):

Mobilization, site prep, etc. = $1,173,431
Replace piers and bearings = $3,008,364
Superstructure repairs = $2,160,766
Upgrade lower decking only (no bicycle deck) approx = $1,500,000
Auxiliary structures (only new pedestrian ramp to lower deck needed) = $300,000 max.
Subtotal = $8,142,561
30% contingency adder = $2,442,768
Total rehab and partial upgrade = $10,585,329

The engineer then added the following statement:

If you take the report statement below (pg 5-15) as correct, the cost to actually repair the bridge and “pretty it up” would be less than 50% of the planned cost of $20+million of the new bridge.

[Report statement] “The cost of rehabilitation should be compared against the replacement cost. Many bridge owners prefer to replace a bridge if the cost for rehabilitation approaches 70% to 80% of the cost of replacement.”

Imagine using this to justify tearing down the Brooklyn Bridge or San Francisco Bay Bridge.

To download the full HNTB report, click below. (Be sure to note the proposed fixes to the problems discussed near the outset.)

2015-07-15-hntb-zink-bridge-concept-report-2015-07-15 Download

Comment accompanying the PDF provided by a Tulsa engineer: “Highlighted are a few things that should answer some people’s concern on safety and what caused the big price increases.”

Some additional notes on the report (conversational) from same Tulsa engineer:

The bridge was not condemned as unsafe for pedestrians. Pg 3-1

2. Major cost increases resulted from trying to put in the upper deck for cyclists. These are the “functional services” mentioned in Chapters 1 and 3.

Bridge could be repaired and its service life extended.

From Chapter 4: “The end of service life for a component of a bridge does not necessarily signify the end of the bridge system service life, as long as the component could be replaced or its function resumed with a retrofit measure. If a component could be replaced or retrofitted, it may be possible for the bridge to continue providing the desired function.”

Most of the repairs were from neglect or never painting steel members installed in the past.

5. It would be prudent to replace the present lower wooden deck with a more durable surface.

The $3 million set aside for lighting system upgrade did not have a design in mind. They merely set that large budget in the estimate to reserve plenty of money. That is a very large number for lighting and would most likely never come close to that number. It should be closer to the $1 million lower limit.

Editor’s note: See this article and this page for more information on the HNTB engineering documents.