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A critical healthcare provider for the local community and home to a care program that serves 3.2 million Kaiser members from Southern California, the Kaiser Los Angeles Medical Center (KLAMC) is Kaiser Permanente’s largest hospital in Southern California. With the recent opening of the seven-story, 700,000-square-foot Stage 1 Rebuild Hospital at 4867 Sunset Boulevard, KLAMC is also now one of the newest hospitals in Southern California and is positioned to remain a leading healthcare service provider in the region for years to come. The collaborative efforts of structural engineering firm Degenkolb Engineers, the architect, and the contractor makes KLAMC a Sunset Boulevard landmark.
Challenges at the epicenter
In the late 1980s, Kaiser completed a detailed evaluation of its existing facilities in California including KLAMC. While considering the functionality of the existing infrastructure and potential to implement new technology and improvements in healthcare, Kaiser also focused on the functionality of its hospitals after a local major earthquake. Based on the evaluation of KLAMC, Kaiser elected to replace the existing 1950s-era facility with a new, modern hospital.
Given the directive to rebuild KLAMC, Degenkolb, SmithGroup, and the rest of the design team faced a difficult challenge. The team, with preconstruction support from Kaiser and contractor Rudolph and Sletten (R&S), had to design a world-class facility while satisfying the Office of Statewide Health Planning and Development (OSHPD) requirements for healthcare construction in the state of California. The new facility had to be constructed in a dense urban environment with no open space on which to build, all the while remaining fully operational until the patients were moved into the new facility.
Based on KLAMC’s programming needs and the project constraints, the design team determined the general shape, size, and function of the Rebuild Hospital. The final design features a seven-story, 840,000-square-foot hospital building with a single basement level that houses the hospital’s acute care functions. Stage 1 of the project is a seven-story, 700,000-square-foot building with a single basement level that was recently opened. There is also a Service Building — a three-story, 100,000-square-foot building with two basement levels that house the loading dock and central plant services and is connected to the basement of the Hospital Building with a two-story tunnel.
Kaiser, the design team, and the construction team established a sequencing of the design and construction that allowed the existing hospital to remain operational during the construction of Stage 1. This sequencing included the following steps:
- design and obtain permits for the Barnsdall Park and Road improvements, Service Building, connecting tunnel, Stage 1 of the Hospital Building, and a possible Stage 2 addition to the Hospital Building;
- demolish an existing parking structure and replace it with the Service Building;
- move into the Service Building and then demolish another parking structure and a medical office building;
- construct the 700,000-square-foot Hospital Building Stage 1 by fully erecting the eastern half, starting build-out, erecting the western half, and finally integrating the new Hospital Building into the rest of the facility; and
- relocate all acute care functions of the existing hospital into the Hospital Building Stage 1 by providing a temporary bridge between the new and existing buildings to facilitate patient transfer.
Constructing a modern hospital
Once the architecture, phasing, and constructability concerns of the different portions of the project were established, Degenkolb Engineers designed structural systems for the Service Building and the Hospital Building. The potentially large seismic forces from an earthquake on the nearby Raymond Fault, approximately two kilometers from the site, governed the structural design. After considering various structural systems and considering the impacts on the architectural design, structural performance, structural loads, cost, schedule impacts, and constructability, the design team selected distinct structural systems for the Service and Hospital Buildings.
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The concrete shear wall lateral force-resisting system and flat slab gravity system provided necessary stiffness and strength in the Service Building’s structure to resist all of the potential loads while also accommodating the central plant services. Because of the tight site, the ground floor loading dock is located entirely within the footprint of the Service Building. Concrete beams and girders were used selectively to transfer gravity columns that would have interfered with the loading dock.
The Hospital Building —While a cast-in-place concrete structure was most appropriate for the Service Building, the project team selected steel as the primary structural material for the Hospital Building. The Hospital Building’s structure consists of metal deck and concrete fill floors supported by structural steel beams and columns. An eccentric braced frame (EBF) lateral force-resisting system is the primary system to resist the potential wind and seismic forces. The resulting structure’s combined gravity and lateral steel weight is approximately 16.25 pounds per square foot (psf).
The EBF system resists lateral loads primarily through the ductile deformation of the link in the frame’s beam while the rest of the frame remains essentially elastic. In addition to the more ductile performance in resisting lateral forces, EBFs also avoid the extremely large and costly gusset plate connections common in high-seismic regions for the brace-to-beam and brace-to-column connections of special concentric braced frames. By avoiding the large gusset plates, the EBFs were much easier to blend into the architecture.
The EBFs were blended into the architecture by working closely with SmithGroup. To maximize daylight into the patient rooms and thereby enhance the patient experience, the architects at SmithGroup designed a building with very large windows. By incorporating a sufficiently long center link in the eccentric brace frame bays, the structural engineers at Degenkolb were able to blend the braced frames into the exterior expression of the building without impacting the large windows.
Project sequencing — Design of the Hospital Building was complicated by the project sequencing. Stage 1 was designed as a fully functioning 700,000-square-foot hospital. Concurrent with the Stage 1 design, a combined Stage 1/Stage 2 building was also designed. With this Stage 1/Stage 2 approach, construction documents for the Stage 1-only building and the Stage 1/Stage 2-combined building were completed simultaneously by the design team, reviewed by OSHPD, and then permitted.
In collaboration with contractors at R&S, structural engineers at Degenkolb tailored the structural design and detailing to expedite construction. The number of unique sections used in the EBF frames was limited to facilitate steel fabrication. With the selected sizes of the structural steel framing, the team at R&S was able to employ just a single crane and still quickly erect Stage 1. Heavier steel sections associated with other lateral systems or fewer braced frame bays would have required multiple cranes and street closures, which would negatively impact the project schedule and cost.
Additionally, critical details needed to facilitate the R&S team’s means and methods were incorporated into the approved construction documents. These intricacies included special detailing for the construction joint between the eastern and western halves of Stage 1, mechanical couplers and form savers at critical interfaces between different phases of the construction, and customized framing around the tower crane. This approach saved valuable time during construction by avoiding the potentially costly and delay-inducing change order process.
Successful results
A structural engineer’s role on a healthcare project in California is not limited to specifying the structural elements and specifying all of the connections and structural details. Non-structural elements such as equipment anchorage, MEP system bracing and support, exterior skin, partitions, ceilings, and soffits often require structural engineering assistance. Failure in the support of one of these elements during an earthquake may be enough to render a hospital non-operational. Consequently, the collaboration between the team of Degenkolb, SmithGroup, R&S, and the rest of the design and construction group also focused on developing coordinated, cost-effective, high-performing solutions to the support and bracing of the non-structural elements.
Kaiser Permanente, Degenkolb, SmithGroup, R&S, and the rest of the design and construction team have delivered a complicated project on a tight urban site in the middle of a high-seismic region. Through the collaborative efforts of Kaiser, Degenkolb, and the dedicated team of experienced designers and builders, KLAMC now features a new world-class healthcare facility that will be there for the community and Kaiser’s Southern California members for years to come.
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Kaiser Los Angeles Medical Center Structural engineer Architect MEP engineering Civil engineering Geotechnical Contractor Construction manager |
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Spotlight: SmithGroup JG: What was the most interesting thing about this project that inspired you during the design process? CC: This project literally began two decades ago. Several aspects both challenged and inspired us, the most unique probably being the site. This is one of the largest, if not the largest, hospital Kaiser Permanente has built. It is shoe-horned into an urban environment bordered by a major thoroughfare, historical park, and a residential neighborhood. The entire project had to be phased like a fine Swiss timepiece — every movement well choreographed and synced. JG: What new design innovations were employed by the design team? CC: There were several design innovations. One of the most prominent and visible is the curtain wall where we used silicon-bonded glazing. This is common for commercial buildings, but the KLAMC is one of the first hospitals in California to be done this way due to building codes. This offers significant cost savings on the project plus allows for a better design aesthetic. JG: What sustainable aspects were pursued by the architectural team? CC: Even though this project started two decades ago, green elements were even being considered then. Day lighting is absolutely essential to the healing process. We designed the hospital to have three major courtyards that allowed for as much daylight as possible. We also designed a comprehensive green roof system, as well as a centralized utility plant to share power to other campus buildings. Sustainable aspects make buildings healthy, as well as the people inside. |
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Spotlight: Degenkolb Engineers Q&A with the structural engineer JG: How was the most challenging aspect of the structural design solved? MB: Integration of a robust lateral force-resisting system into the Hospital Building architecture was one of the more challenging aspects of the project. Unbalanced soil loads including three stories of unbalanced soil load on the Service Building, the set-backs, courtyards, the project phasing, the possibility of a Stage 2 addition, the Office of Statewide Healthcare Planning and Development requirements for the building design and construction, escalation in material prices … all of these elements of the project made it challenging. In the end, we were able to implement cost-effective structural systems that blended with SmithGroup’s architectural vision and was capable of resisting the potentially large seismic forces from an earthquake on the adjacent Raymond Fault. JG: Were there any construction considerations that affected the structural design? MB: Constructability, given the site limitations and phased nature of this project, was a central issue. We had to keep that in mind from the inception of the design. For example, by coordinating the eccentric braced frame locations with SmithGroup and R&S, Degenkolb was able to keep the steel framing sizes small enough so that R&S, and their steel fabricator/erector Strocal, could erect the Hospital Building using a single tower crane. JG: Is there anything you’d like to discuss? MB: While this project was being developed, the state of California mandated through SB 1953 that all existing hospitals be capable of providing a minimum level of structural performance during an earthquake. In essence, the law required that existing hospital buildings that would perform poorly in an earthquake be removed from service, retrofitted, or replaced. This project was initiated by Kaiser after their evaluation of the functionality of the original KLAMC concluded a replacement hospital was needed and before SB 1953 was conceived. Since this project does satisfy the requirements of SB 1953, additional work to comply with the law is not needed and the Service Building and Hospital Building will be able to house acute care services for years to come. Firm Facts |
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Matt Barnard, S.E., P.E., is an associate principal at Degenkolb Engineers. He can be reached at mbarnard@degenkolb.com. Special thanks to Jay Love, David Lee, Madeline Field, and Alethea O’Dell at Degenkolb Engineers, as well as Carl Christiansen at SmithGroup and Tom Conroy at R&S for their contributions to the article.
