CABRILLO Historic Structures Report

The following section summarizes information on each of the nineteen structures dealt with in this report, including their location, a brief history, physical description, current condition and a structural analysis. Information on structures of similar type, such as the two end stations Calef & Wilkeson, is grouped.

The structures are concentrated primarily in two locations. Structures on the east side of Point Loma overlooking San Diego Bay are accessed via the Bayside Trail and those located on the west side facing the Pacific Ocean are accessed by roads.

The subject structures are primarily reinforced concrete construction, with concrete floors, walls and roofs. Most of the structures are partially buried beneath the ground or bermed into the hillside. Variations from this typical description include the wood-framed roof of the army radio station, the steel-framed roofs of the searchlight shelters, the primarily corrugated steel pipe bunker complex structures, and the circular concrete gun emplacements, almost fully buried in the ground.

STRUCTURAL SUMMARY

Based upon visual observations (structural drawings are not available), the existing structures typically appear adequately sized and constructed to resist the expected vertical (gravity) and lateral (wind and earthquake) loads. Because they were designed for military purposes, they would likely have been intended to withstand substantial forces. Hence the concrete walls and roofs appear to have been provided with generous thicknesses and reinforcing.

Some deterioration has occurred in the reinforced concrete walls and roofs. This consists primarily of cracking in the concrete walls and localized spalling of the concrete, with the reinforcing bars exposed and corroded in some locations. In addition, the steel components of the structures are corroded in many areas. This deterioration is consistent with the age and weather to which these structures are exposed. In most cases the deterioration is not advanced enough to significantly compromise the integrity or capacity of the structures, however if left unchecked it will eventually become a problem. Specific locations where this deterioration is more significant are noted in the evaluations.

Figure 3. Cabrillo National Monument historic harbor defense structure locations. (click on image for an enlargement in a new window)