On a California beach, manhole shafts provide a delightful alternative to block construction for restroom facilities.
By Fernando Pagés Ruiz
Most people who use the stylish showers and privies located along the picturesque, white sand beaches of San Buenaventura State Beach in Ventura, Calif., don’t realize that they have actually stepped into a manhole. When Jim Pleasants, general manager of Inland Concrete Inc. in Riverside, learned that his precast manhole shafting would become an architectural component, he explained to the project architect, “These pipes are not finished for above ground applications. They’re, well, rough!”
As it turns out, this was exactly what Tony Keith had in mind when his firm, RRM Design Group, was challenged to come up with a new design for the San Buenaventura bathroom facilities. Keith faced a daunting criteria: Design modern bathroom facilities that combine vandal-proof durability, low cost and a 1960s vision of the 21st century – not to mention making sure the structure was ecologically compatible with the seascape. It was a task that would require plenty of head scratching.
Keith had previously designed many facilities for the California Department of Parks and Recreation, so he understood that his client wanted to highlight the unique characteristics of each state park with original landmark architecture. In this case, San Buenaventura State Beach had been developed in the 1960s and the parks department was looking for something best described as “nostalgic-modern,” says Keith. “Something in the George Jetson genre.”
Unfortunately, they couldn’t afford a budgetary departure from what had been a purely utilitarian approach to facilities design. Construction for park facilities usually consisted of a concrete block box with a wood-framed roof and very little imagination. To combine originality with cost control, Keith reasoned that whatever material he chose, it would have to resemble concrete block in its availability, price and modular construction flexibility. He struggled with a solution until, one day, while sitting at the design table, scratching a bald spot into his head, a fortuitous glance outside the window revealed the solution.
Coursing down the road right in front of the office, Keith spotted a big rig loaded with precast concrete sewer pipe. “That’s it!” he thought, realizing he could use large-diameter, round segments of precast to build individual bathroom stalls quickly and inexpensively. After phoning a few precast concrete producers, Keith confirmed the viability of his inspiration. By stacking 30-inch high, 8-foot diameter manhole riser sections, a tower of precast concrete cylinders could be combined in inventive clusters to build bathroom facilities that joined economy with flair.
Of course, the idea required a lot of refinement. But in the end, the RRM Design Group persuaded the California Parks Department to try the idea. The bathrooms and showers evolved into a cluster of two and three precast concrete towers about 20 feet tall. To accommodate the doors, Inland Concrete created a custom manhole sections with blockouts for openings. To shed water off the roof, the precaster built a cleaved pipe segment, upon which the designers specified a simple translucent polycarbonate sheet on a standard fiberglass grid commonly used for industrial decking.
Although Keith wanted to preserve the rustic character of the manhole, the material proved a little too rough and uneven for a cohesive architectural aesthetic. But instead of plastering or painting the material to disguise it, Keith decided to sandblast the cylinders and bring out the cobbled texture of the aggregate. The resulting finish complemented the colors and textures of the rocky shoreline.
To attach the cylinders, RRM Design Group used carbon fiber matting adhered with epoxy. The combination of the precast concrete cylinder’s compressive strength with the tensile strength of carbon fibers resulted in a practically indestructible assembly.
Furthering the Parks Department’s goal of thwarting vandalism, Keith connected the cylinder clusters in groups of three, shaped like a triangle, with three precast concrete wall sections connecting the towers to provide a screened shaft for mechanical access. The shaft also holds trash receptacles, accessible to the public through a slot, so that only park maintenance personnel can access them. This configuration provides a neat, clean appearance for patrons and eludes malicious mischief.
After building the facilities, Jon Hanson, owner of Hanson & Son Construction, has mixed feelings about the ultra-modern appearance, but he has no doubt that precast concrete components saved him time and money over cast-in-place construction. “I can’t imagine trying to form and pour this sort of thing on site,” says Hanson.
Besides saving labor on the job, Hanson points out a less obvious cost benefit of using precast concrete components in any municipal application. “When you take into account the prevailing wage requirements on government projects,” explains Hanson, “precast products make a lot of sense. The manufacturer does not have to pay his laborers nearly $40 an hour like we have to on site.”
This combines with the benefit of ordering precast concrete components early in the job sequence so that by the time the site is prepared, it’s just a matter of assembling the finished product. In this case, Hanson says assembly went quickly, despite the novelty of the materials used and the design. Hanson says the resulting structure is permanent and almost maintenance free.
Maintaining a landmark
During the design phase, RRM architects met with park maintenance personnel to solicit advice about the facility’s upkeep. Besides outright property damage, the crews complained about the difficult task of cleaning graffiti. By coating the interior of the precast concrete cylinders with epoxy paint and treating the exterior with a translucent epoxy sealant, park crews can easily clean off any paint with light scrubbing.
Although the quasi-sculptural facility hasn’t yet met the test of time, Barbara Fosbrink, chief facilities manager for the California Department of Parks, feels confident that the innovative landmark will still be in use 50 years from now. “There are no plans to re-create the same facility in another park,” says Fosbrink, but she hopes that “other architects will draw inspiration form RRM Design Group’s creative use of precast components.”
The towering final touches
If you are into kite boarding or wind surfing, you probably know about San Buenaventura State Beach. The cove is famous for its unique combination of calm seas and strong winds. To tie the precast concrete towers into a cohesive unit that complements its unique surroundings, Keith designed a canopy of three triangular nylon sails that soften the silo-like monoliths and pay tribute to the wind.
More than just a practical, maintenance-free facility, the creative use of precast concrete manholes has provided San Buenaventura State Beach with a distinctive identifying landmark. You can see the towers capped by colorful sails from anywhere on the beach, and they have become a meeting place and geographic reference point for park patrons. From subterranean sewers to seaside monuments, only human imagination can limit the application of precast solutions. After all, creativity, like fine cooking, is all about new combinations of very old ingredients.
Project: San Buenaventura State Beach Facilities, Ventura, Calif.
Owner: California Department of Parks and Recreation, Sacramento, Calif.
Architect: RRM Design Group, San Luis Obispo, Calif.
Contractor: Hanson & Son Construction, Oxnard, Calif.
Precast Manufacturer: Inland Concrete Inc., Riverside, Calif.