Nibbi Brothers was proud to be involved in a project that gives back to the community. In 2003, work began on the African Savanna, which was part of a $100-million bond measure to upgrade and renovate the San Francisco Zoo.
Created on existing zoo land, the 3+-acre site has been transformed into flat, treeless grassland, featuring African wildlife in a large, multi-species environment. The new exhibit was designed to give animals the space to interact and move about. Nibbi’s scope of work included removal of existing trees and construction of the pedestrian walkways, the holding barns and paddock. The two major buildings constructed for the project were a giraffe barn with a 43-foot roof in the northeastern section of the savanna and a hoof stock holding barn in the northwestern savanna. The hoof stock barn will be the new home to zebra, antelope and African birds, including ostrich, ground hornbill, white-bellied storks, waldrop and the sacred ibis. Both barns have adjacent outdoor paddocks for the animals.
The exhibit consists of the North and South Savanna, a contiguous space bisected by the Donga, or dry riverbed, which serves as the pedestrian walkway. Marking both ends of the riverbed are large engineered rocks, which are truly one of the most unique elements of the project. Manufactured and assembled by Tucson-based CemRock Natural Landscapes, each engineered structure began with a concrete foundation outlining the footprint of the rock. After the concrete was cured, crews bent the rebar to form to a predetermined shape. This enabled them to construct the rocks per the architect’s specifications. Rebar was drilled and epoxied into the tunnel, and then shaped after the epoxy was set. Wired burlap was then tied behind the rebar to create a backing so that when the shotcrete was applied, it had something to conform to. In front of the burlap, metal lath was then tied to the rebar, giving the shotcrete another medium to adhere to. This structural layer is about six inches thick. After the structural layers cured, a second 3-inch layer of brown colored shotcrete was applied. The crews troweled the brown concrete while it was still wet to give the rock its final shape, cutting in cracks and crevasses, in addition to patting the rock with a stiff brush. This gave the concrete a dimpled appearance and its final shape. After the colored layer was cured, a team of artists painted the rocks with a wide variety of colors, mimicking the colors from the model, giving cracks and crevasses darker shades, while surfaces that are constantly exposed to the sun received lighter colors. The rocks are designed to mimic a type of rock called kopje, which are indigenous to the savanna areas of Africa. Both the architect and owner are very happy with the final product.