The Dangers of Demolition

The Orange County Legislature has approved a plan to renovate the iconic Paul Rudolph designed Orange County Government Center that will irrevocably alter its appearance by removing the signature corrugated concrete exterior walls. In fact, their plan as currently approved, is to gut the building to the floors and columns before beginning renovation.

There is currently a lawsuit attempting to stop this plan based on it being an unnecessary waste of taxpayer funds.

But there is a very important environmental concern that isn't being addressed. Namely, removing all that old concrete, crushing it, and burying on the property has very dangerous environmental costs. There will be massive amounts of concrete (estimated to be about 10,000 tons) that must be crushed locally. Crushing causes noise and dust. These conditions could exist for long periods of time. Concrete is alkaline and burying the concrete locally will drastically change the pH of ground water.

EXECUTIVE SUMMARY – 10 key points :

 1.       The planned renovation will irrevocably alter the building by demolishing the signature exterior, as well as gut the building down to the floors and columns—But aside from the questions that have been raised about the project’s unnecessary expense to taxpayers, there are very important environmental concerns that aren’t being addressed.

2.       Removing all that old concrete, crushing it, and burying on the property has potentially very dangerous environmental consequences.

3.       If the plan proceeds, massive amounts of concrete (estimated to be about 10,000 tons) must be crushed on site.

4.       Crushing causes intense noise and dust.

5.       Concrete is alkaline and burying the concrete locally will drastically change the alkaline content of ground water.

6.       In 2013, State Departments of Transportation were surveyed on their use of recycled concrete aggregate in roadways. About half of the respondents mentioned problems, including high alkaline levels related to chemical reactions, groundwater leaching; and debris and contamination.

7.       Orange County’s own commissioned report stated that the depth of ground water ranges from 3 to 13-1/2 feet on the site—and these depths would be chemically affected by buried crushed concrete.

8.       That immense amount of rubble has to go somewhere—and the site can only take so much (or they’d have to raise the level of the land)—So will the rubble have to be relocated?—and if so:   Where?  At whose expense??

9.       The legislature has offered no clear & convincing answers to these very serious questions:

·         How will the community deal with the noise this will create?

·         What is being done to address the dust this will create?

·         What is being done to address the alkaline groundwater this will create?

·         Who would be affected by any poisoned ground water?

·         Where are they going to put all the recycled concrete? (Will it really fit on the 0.7 acre construction site?)

·         Who will bear liability for all this?

10.   These negative conditions could be dangerous, expensive, and last for very long periods of time.

We recently contacted Vincent DeSimone, a prominent engineer, who worked with Paul Rudolph on other projects and was familiar with the construction of the Orange County Government Center. He is the President of DeSimone Consulting Engineers, a world renowned engineering firm,  and he told us: "We are not demolition experts but I remember the design vividly and I must say that the structure for this facility was very robust. Much more so than a conventional building. It would require a very dirty demolition procedure either implosion or a very tedious manual demolition. Either process will create tremendous noise and air pollution. As I recall the actual [buildings] had concrete walls which were supported on a number of linear girders. As a result of the dimensions of the girders, they were chock full of reinforcing. My opinion is that if the demolition was Manual rather than implosion, the facility would have to be shored thru out and a very slow process of sawing and pneumatic hammering would be necessary. In either event it will be very expensive to demolish by hand and environmentally unacceptable to demolish with explosives."

The Orange County Legislature commissioned QCQA Labs to prepare a GEOTECHNICAL ENGINEERING REPORT. QCQA Labs released this report in May 2014. On page 7, section 3.3, the report stated that ground water ranges from 3 to 13.5 feet underground at the site. These are depths that would be affected by the high pH resulting from buried crushed concrete. Who would be affected by this poisoned ground water?

On page 59 of the same report, the engineer states:

"All controlled fill placed beneath foundations, structures, utilities, slab-on-grade and pavement construction should be compacted to a minimum of 95 percent of the maximum dry density as measured by the modified Proctor test (ASTM D1557), or as directed by the geotechnical engineer. Fill placed in non-loaded grass areas can be compacted to a minimum of 90 percent of the maximum dry density (ASTM D1557). Placement of fill should not exceed a maximum loose lift thickness of 6 to 9 inches and should be reduced in conjunction with the compaction equipment used so that the required density is attained. Fill should be placed in level lifts. Where fill is placed on sloping ground, the fill should be “benched” into the slope.

With those limitations, can the site take all the concrete rubble or must a large amount be disposed elsewhere and at what expense?

In 2013, the state DOT’s were surveyed on their use of Recycled Concrete Aggregate (RCA) in roadways. Some of the results of the study were: About half of the respondents discussed problems in using crushed concrete as aggregates, including high pH levels related to the alkali-silica reaction (ASR) and groundwater leaching; high absorption of crushed asphalt concrete; and debris and contamination.

In a study published at Oxford University in 1990 on concrete recycling worldwide, it was noted that:

  1. A mobile recycling plant has limited debris cleaning facilities and therefore the recycled aggregate is normally of low quality.
  2. The mobile recycling plant can cause high levels of dust and noise which would be unacceptable close to residential areas.
  3. This type of plant can only be used if there is sufficient quantity of rubble on the site to justify the expense of setting up the recycling plant

If rather than bringing an expensive mobile recyling plant to the site, the contractor merely uses a pulverizer, the capacity of a larger pulverizer is only about 50 tons per hour and it will generate even more dust and noise pollution. Note that 10,000 tons would require such a pulverizer to work 200 hours to pulverize the required amount of concrete.

Lets look at some calculations --

A finely recycled concrete for fill is usually crushed to a 1.5" to 3" size and weighs 1.3 tons per cubic yard. (This size is achieved with a mobile recycling plant. A pulverizer attachment will not achieve such a fine fill, and it would be even less dense resulting in a greater volume per ton.)

10,000 tons of recycled concrete would generate at least 7,692 cubic yards of fill.

The latest SEQRA filing says in item D.1.b.b that only +/- 0.7 acres on the site will be disturbed.

0.7 acres is equivalent to 4,840 square yards.

7,692 cubic yards of fill spread over the entire 4,840 square yards would result in fill 57 inches high (just under 6 feet high)!

It boggles the mind to think that the contractors will raise the entire site almost 6 feet high with recycled fill...or do they actually plan to disturb more than the 0.7 acres legally certified in the SEQRA filing...or will there be an additional un-budgeted cost to haul all this debris away?