The Shriner’s Hospital for Children in Sacramento, California, serves as the gateway to a multi-functional redeveloping medical center. Situated in an old neighborhood populated with brick residences, the nine-story hospital and its adjacent three-level above grade and three-level below grade parking structure had to reflect the existing heritage while also projecting a contemporary image. To achieve this goal, the designers created a façade using architectural precast concrete featuring spandrel panels with two sandblast finishes incorporating a variety of reveals, a band of red granite and green terra cotta medallions that protrude attractively from the wall. The adjoining parking structure also is clad with architectural precast panels that reflect the style of the hospital façade. This was all accomplished while satisfying fire safety regulations and Seismic Zone 3 code requirements.

Challenge

Executives at Shriner’s Hospitals for Children prefer to position their medical facilities in close proximity to teaching hospitals. That relationship benefits both organizations, but it also generates additional design challenges for producing a cohesive aesthetic exterior design. Not only must the hospital fit into the surrounding neighborhood and the physical site restraints, but it also must blend with the adjacent medical campus while projecting the strong image of the Shriner’s Hospitals fraternity.

The hospital's design also had to address changes in the health-care industry, such as shorter patient stays, increased focus on outpatient care and family-focused care. This meant adapting traditional designs to create more community-gathering areas, better access and transportation for out-patient arrivals and departures and other elements affecting interior and exterior design driven by changing patient needs.

Additional Challenges

Creating the curved panels to clad the entire main facade provided another significant challenge for Clark Pacific. Precast concrete panels featuring nine different radii had to be worked out, with three materials integrated into most of these panels. As a result, Clark Pacific devised more than 20 different panel geometries, including curved architectural precast spandrel panels with integral soffits. Twenty-one different steel forms had to be constructed to mold the panels, with as many as 20 different form casts on any given day to meet the specific shapes and number needed. These custom forms produced extremely tight tolerances on the panels, minimizing erection problems once they arrived on site.

Due to the seismic zone, Clark Pacific used push-pull connections at the lower levels of the panels as well as the cast-in-place bearing connections at the tops. The panels were designed to accommodate 2 inches of lateral drift on each floor, giving them sufficient ductility in the event of an earthquake. The precast panels required special connections, which Clark Pacific typically uses on such designs in this seismic zone. These are comprised of closed-loop straps on the back of the embedded piece, through which the mild reinforcing steel is run. This added reinforcing ensures the embed and panel remain attached even under extreme seismic vibrations.

Solution

Aesthetically, this high profile positioning meant the structure had to blend into the context of the major medical center while also responding to the architectural design of the surrounding neighborhood. The area features many old brick homes, with a dominant Spanish Colonial style. Neighbors were concerned that the new facility would stand out too dramatically with its need for contemporary styling and large mass. Clark Pacific worked closely with local citizens groups to reassure them and receive their input on many concerns. In all, six neighborhood associations reviewed the final building plans and provided input on appearance issues.

The hospital was also designed to have a circular, sun-filled atrium that continues through all of the above-grade floors. The basic design of the hospital resembles a square with a quarter circle carved out of one corner. This helped reduce the visual mass of the building against the residential neighborhood it adjoins while providing a dramatic face to present to traffic as visitors approach the hospital.

Clark Pacific created and installed some 1400 architectural precast panels which were used to clad the facility. These panels range in weight from 1700 to 32,000 pounds and feature considerable complexity in their shapes, owing especially to the curved form of the main facade. In addition, red granite insets were provided to create an intermittent horizontal dark band running the length of the building at every storey. This reflects the surrounding brick architecture of the neighborhoods, giving them a touchpoint that ties the hospital to them without surrendering the facility's need for a contemporary, strong image.

Green terra cotta medallions that protrude attractively out from the wall were also interspersed among the granite bands at spandrel intersections to add further detail and interest. By providing two different levels of sandblasting, Clark Pacific was able to create a contrasting finish to the windows, with reveals added between and around the insets and bands.

Parking Structure Matches Design

An additional challenge came in the form of the adjacent 650-car parking structure that connects to the hospital via a wide, second-level pedestrian walkway. This building is prominent along the main thoroughfare and combines with the hospital to form the campus' new gateway image. That meant it had to present a unified front with the main facility and avoid a parking garage type of image. The large scale of the structure and the need to blend with the elegant architecture next door posed a distinct challenge in its design.

The most significant consideration came in the need to include a children's play area for the adjacent hospital on top of a portion of the parking structure's roof. This incorporates both hard and soft play surfaces, meaning both asphalt and grass, as well as an area planted with vines growing on top of trellises, providing both shade and natural stimulation for the rehabilitation of patients. Adding this function to the parking structure required that it include a separate and higher fire rating than the rest of the building. Precast concrete easily met this requirement.

Children's Play Area is Prestressed

The large post-tensioned beams supporting the play terrace's deck had a unique stage-stressing requirement. All final dead loads that were to be supported by these beams had to be placed on the deck prior to final tensioning of strands. This included not only all of the soil fill that was being used in the planters and decks for the natural grass areas but also the precast concrete panels that close up the structure prior to attaching the internal portion of the full-wrap column covers. This required all of the column covers and sill panels to be set temporarily and braced out of position as close to final position as possible. Once completed, the length tensioning process began. When finished, all of the panels had to be reset and welded into their final position.

Puzzling Results

Overall, many elements of this project made it resemble a three-dimensional jigsaw puzzle with each piece weighing 10,000 lbs. It required considerable preplanning and discussion among Clark Pacific, the architect, and general contractor to make it work properly. Through their mutual efforts, teamwork and ingenuity, the work progressed smoothly and quite rapidly.