Seismic retrofits and structural repairs were needed for the Morro Hills Reservoir to minimize earthquake vulnerability and ensure the safety, security, and reliability of the City of Oceanside’s water supply. Services provided by Beyaz & Patel for the Morro Hills No. 1—an above ground, 5.0 MG pre stressed concrete reservoir—included structural engineering analysis to define additional details specific to the site, apply site specific parameters from the geotechnical investigations, and develop design alternatives and final detailed design for structural repairs and upgrades. Analysis included structural calculations to assess the seismic resistance and code compliance and finite element analyses to optimize the structural design. Final design included a complete seismic retrofit of the reservoir.
Structural deficiencies included a lack of seismic cable, circumferential hoop over stress, dome roof ring girder over stress, extensive concrete cracking on roof slab, and extensive concrete cracking on floor slab. The retrofit addressed these deficiencies by adding seismic cables to address the overturning coverings, adding to wire strands to wall and roof ring girder to mitigate hoop over-stress, and repairs to the concrete cracks in the roof and floor slab.