In order to comply with the State of California’s new
sustainability regulations while providing the durability to outlast other
systems that have failed in the past, Meyer + Silberberg Land Architects turned
to T.B. Penick & Sons, Inc. to find a solution to these requirements while
maintaining a look that fits in to the natural landscape of the Presidio. The
answer to these requirements is T.B. Penick’s new Pervious Concrete Elements™
system which improves pervious concrete by solving its aesthetic deficiencies while
providing a smoother walking surface. Pervious Concrete Elements™ opens the
door to an unlimited range of colors in glass, aggregates, and integral color
while providing the functionality of standard pervious concrete.
According to Adrienne St. John of Meyer + Silberberg:
“The National Parks Service works hard to maintain a natural
look in a park that is hugely popular: Battery East alone gets more than 7,000
visitors per day. Paving needs to be very durable, ADA accessible, and yet also
look like it fits in to the natural landscape of the Presidio.
The Park has tried out numerous paving materials over the
years, and learned about a lot of potential problems. Decomposed granite
doesn’t usually meet ADA. Stabilized DG systems have proven difficult to
install correctly, and don’t look good when repaired. This plaza is adjacent to
a bike lane, and we didn’t want loose aggregate to be scattered on the
road surface, so a bonded aggregate material was important.
The parks have used permeable concrete in the past, and have
been satisfied with its durability, but it didn’t give the look they wanted. TB
Penick allowed us to customize the aggregate and concrete mix colors for a
natural decomposed granite look, that blends with the site. Penick provided
custom samples and a large scale mock-up on site for client approval.
The environmental and regulatory reasons for choosing
permeable concrete were a bit more complex:
The State of California has implemented new sustainability
regulations that require new projects to reduce the volume of stormwater runoff
that projects generate. If we had paved the plaza at Battery East with an
impermeable material (traditional concrete or stabilized DG) we would have
needed to concentrate the plaza runoff in bioswales and let it percolate into
infiltration basins—which simply wasn’t feasible. We couldn’t concentrate
stormwater in different parts of the site because there were buried historic
batteries that we didn’t want to damage, there was a slope that we couldn’t
risk destabilizing, and there was risk that buried contaminants left by the
army might be spread underground.
The safe way to proceed was to let the rainwater infiltrate
directly in the plaza, with a permeable paving material.”
Battery East’s history:
Battery East, once an integral part of San Francisco Bay
defense, is located on the coastal bluffs of the bay near the Golden Gate
Bridge behind Fort Point. It was first built in the 1870’s due to advances in
artillery during the civil war which proved that masonry forts such as Fort
Point were unable to withstand bombardment by heavy ordinance. This led to
innovative revisions in seacoast defense. Battery East was the result of such
innovation, and was completed during the Spanish-American War of 1898 with the
installation of 8-inch Rodman cannons to protect the bay, and by extension the
entire Pacific coast. Although no longer in use, Battery East’s earthen works
built to protect the large Rodman guns are still visible as are the brick-lined
magazines used to store ammunition.
Today, Battery East serves a different purpose. Thanks to a
grant from the Tiffany Foundation, the trail and vista located at the site were
designed to highlight the 1870’s fortifications under and adjacent to the site,
as well as provide an introduction to the Golden Gate bridge for visiting
cyclists and hikers. The new Battery
East Vista also features stadium seating and accessible viewing areas overlooking
the stunning coastal bluffs, the Golden Gate Bridge, and beautiful surrounding vistas.
The renovation of Battery East first began back in
2012 in anticipation of the 75th anniversary of the Golden Gate Bridge
and was later completed by 2015. T.B. Penick was proud to be a part of this
project and was tasked to install our innovative Pervious Elements system along
the trails and plaza due to the durability and beautiful aesthetics of Pervious
Elements along with its functionality as a porous concrete system.