Paving the Islands towards the Marina
With a growing number of suburban McMansions declared wasteland in recent times as a result of poor quality, one wonders where invisible construction quality has survived the battlefield of the economy. One place that keeps going strong as a result of visible and invisible quality demands is Oyster Bay Harbour and Yachtclub.
Recently we witnessed road paving activity going on on the island between Waterway Oaks and the Yachtclub, as the development is ready to add another phase of cottages and town homes to the offering. In a time when road surfacing is only afforded as a government stimulus project, Oyster Bay continues to build on its vision of quality and preservation.
With a solid involvement in resort communities and residential developments across the globe since 1973, I have experienced only a handful of properties in the class of Oyster Bay Harbour. And even though I have heard some people claim it’s too far out or too quiet or too wooded or too elaborate, they all miss the true diversity that the marshes and the location offer. Last weekend we took the boat out for a daytrip to Cumberland Island and again it struck me how quickly we were passing historic downtown Fernandina. Faster than by car. Having a condo in a marina may sound attractive when you’re 30 without children, but with children and a daily routine it becomes a huge hassle. Having a house in the suburbs with a 30 ft. Bay Cruiser for weekend fishing sitting in the driveway, is a nuisance that ultimately leads to getting rid of the “toy”. Oyster Bay Harbour has the perfect scale and distance to live majestically and have the boat in the river on a moment’s notice.
That’s life, without being charged extra.
What I personally admire in the OBH siteplan is the way the residences are built around nature. When you move into a newly built home, nature is fully intact because trees, bushes and brushes have been spared wherever possible. Most developments start out with moving bulldozers in. Not here.
As Marc’s overall vision to preserve nature was a mission in itself, it took project supervisor Shaun Harrell to make sure it could actually work inside of the financial parameters. I had the opportunity recently to spend a weekend in a glorious isand villa next to the yachtclub facilities. This villa was staged for sale last week by Fabulous Homes and Fabrics on 8th Street, but more about that later.
What was intended to be a Friday night and Saturday, stretched easily into late Sunday evening before we hit the road back home across the bridge onto Amelia Island and up to the beach. We actually didn’t miss the beach that weekend. If you’re interested in our bike trips, fishing from the docks, lazying around the pool, enjoying a Clubhouse wedding with Cajun tunes or just gazing over the marshes in a painter’s palette sunset, check out some stories on this website.
A story I could never do enough justice however, is the one that explains the invisible (and sometimes visible) quality of a meticulous execution of the master plan. As Oyster Bay Harbour is getting ready to add several dozens of Island Cottages between the villa area Waterway Oaks and the Yachtclub, the traffic structure was recently laid out and paved in a way that saved nature and its location almost entirely. The impact of all pieces of heavy equipment was so “remote” that even the famed “Bird Sanctuary” and the Roseate Spoonbills that have made OBH their home, never felt threatened.
The execution was done so underhanded and unpretentious, that the next night, when we had our monthly European American Business Club meeting at the Yachtclub, none of the 40 or so members, had a notion that roads were just paved a day earlier. Nature was literally undisturbed, and no matter if you have a conscious notion of these balances or not, it takes pure artistry to pull that off. Reason why I asked Shaun Harrell to outline the process and execution, more for my own satisfaction that the reader, no doubt.
Here is Shaun’s story on what it takes to put a road through Oyster Bay Harbour:
1) Subgrade: The roads at OB are mostly built on a sandy soil. However, in some places we had to remove a layer of “organic soils” to find the sand layer. You cannot compact organic soil so it has to be removed and replaced with “structural grade fill’. Soil samples are sent to a lab to determine the maximum level of compaction the soil can yield. Heavy vibratory rollers are used to compact the soil and it is tested to be certain it meets or exceeds the lab specifications. All of our tests exceeded the specifications.
2) Base: County specifications for road base requires six-inches of limerock. Limerock is a fine sandy material that contains lime (calcium carbonate) that can be compacted to higher levels than subgrade soils. A lab will specify the compaction requirement as an LBR (Limerock Bearing Ratio). One of the problems with limerock is it can loose some of its compaction if it becomes wet. Since Oyster Bay is in the marsh, the natural level of the ground water is only a couple of feet below the surface. During the summer rainy season or during a tropical cyclone there is a good chance that ground water levels will saturate the limerock. It could loose compaction, creating potential problems with the roads. We asked the County to allow us to use crushed-up concrete, known as crushcrete, as a substitute. We worked with W.R. Townsend in Jacksonville and used crushcrete made with 6,000 psi concrete. Instead of the meeting the County’s minimum of six-inches we installed eight to ten inches of crushcrete. The crushcrete is compacted with heavy vibratory rollers until it meets or exceeds 98% of maximum LBR. All of our LBR tests exceeded the lab specifications. In fact, the base was so compacted; in some cases the lab’s testing rod would not penetrate the base.
3) Pavement: The County’s specification is for 1½ inches of asphalt pavement. I consider this a minimum standard. Prior to authorizing the paving, I confirm that the height between the top of the road base to the top of the curbs about two-inches. When the paving crews spread the hot asphalt they use the top of the curb as a guide. Roads that are built properly (subgrade & base) seldom have problems in the center of the road. However, if roads are built to the minimum County standards, over time the edge of the pavement near the curb can degrade. Increasing the depth of the pavement to at least two-inches at the curb helps prevent the problem. When the 305º to 325ºF asphalt is spread on the roads it is left about a half-inch higher than the curbs. Soon after, rollers compress it down to the finished grade. The section that Duval Asphalt paved last week used ten-tons more asphalt than would be expected on a road built just to County standards. This construction is more typical of State highways designed for heavy use like construction, logging and military vehicles.
4) Curbs: Concrete curbs are not required in Nassau County road specifications. Next time you are driving around study the County’s roads; except in the City areas you will not see curbs. Over time the outside edge of the asphalt cracks and breaks away (very obvious on SR 200 from the heavy logging trucks.) Since the homeowners association will maintain our private roads, every effort is made to build them correctly. Curbs are expensive costing about $16 to $20 per foot and are installed on both sides of the road. Once installed, the asphalt is locked between the curbs preventing the cracking and breaking at the edge. The reason asphalt is used is that it is a flexible surface: over time (especially on hot summer days) it will mold and bend. A good subgrade and concrete curbs keep it in place.
5) Drainage: To prevent the obvious risks of driving through standing water, the roads must be built to channel several inches of rain off of the roads. Preserving the ancient live oaks and working with a relatively flat ground are especially challenging for stormwater drainage. Once the subgrade is compacted, curbs are installed. All of the drainage flows are “set in concrete” when the curbs are installed. Our curbs were set with vertical tolerances of less than one-half inch. Most of curbs in the new section are called ribbon curbs; water is designed to flow off of the flat surface. The other curb we use is called “high-back” which, as the name implies, has a six-inch tall back. Water is designed to spill out of the curb (not flow over.) Compass Point Circle has a fourteen-foot wide pavement that allows for one-way traffic only. We used high-back curb on the inside (driver’s side) and ribbon curb on the outside. The circular road tilts several inches toward the outside, channeling rain to runoff the flat curb into wide, shallow basins in the woods. Several parts of Bay View Drive have ribbon curb on both sides of the road. In these sections the road is higher in the center, or crowned, and sheds rain off on both sides. When the roads are near obstructions or higher than the natural ground levels, we use the high-back curbs to prevent cars from driving off the road. The real art is to smoothly transition from a crowned road to high-back curb and back.
6) Design vs. field modification: Most roads in Nassau County are two-way roads that have a minimum width of 20 feet. Working with a survey of the exiting trees, the roads at Oyster Bay were snaked around the trees. Adding the curb on both sides of the roads makes our roads 23-feet wide. To maximize safety, the turns use a radius of 100-feet at the center of the road. Landscape islands were used to preserve specimen trees. In some cases using a 14-foot wide one-way road offered more opportunity to save trees than the wider two-way road. This was used on Compass Point Circle.
In closing: There are always things that look good on paper that look different in the field. For example, when we started building the intersection of the one-way road and Bay View Drive, there were three nice live oaks in the way. We redesigned the “T” intersection into a “Y” intersection. The designs were discussed with Nassau County and received support from Rodger Henderson with the fire rescue department. (A lot of the road standards are to facilitate access for emergency vehicles.) We were able to save all three trees by splitting the road into two 14-foot wide lanes. There was another opportunity to save a live oak. The original plans showed the 20-foot road going between two trees. The faces of the trees were exactly 22 feet apart – our road was 23-feet wide with the curbs. Our choice was to remove either of the trees and shift the road. We decided to stop the curbs a few feet short of the trees and install a section of pavers between the trees. This meets the County’s 20-foot wide driving surface (curbs are optional) requirements, hopefully saved the trees and the pavers will give the tree’s roots the needed flexibility.