Construction of the UCSF Health Helen Diller Hospital is progressing in San Francisco’s Parnassus Heights, with two WOLFF 1250 B US tower cranes serving as the main machinery on a site bordered by residential areas, forest, and the existing hospital.
The new 15-storey facility, a $4.3bn project, is being built directly adjacent to active hospital functions, requiring extensive logistical planning and regulatory compliance to allow medical operations to continue uninterrupted.
Only five WOLFF 1250 B US cranes are currently in operation in the US, and this build marks the first occasion where two have been deployed together on an American construction site.
Each crane can lift up to 40t in two-fall operation and up to 19.7t at the tip of its 65m jib.
Due to severe space constraints, the cranes were installed along the plot’s perimeter, enabling access to large sections of the site while ensuring that they could remain for both structural and interior phases of the build.
The XXL luffing cranes, which were erected in 2025, have a compact tower footprint of 3.3m by 3.3m but reach approximately 85m freestanding, and 152m with their jibs raised.
Traditional crane foundations were not feasible due to seismic, geological, and surrounding utility concerns, so the installation used purpose-engineered foundations of pipe piles and steel grillages.
The WOLFF cranes handle not only standard hospital construction materials, such as rebar and steel, but also support the entire site’s logistical needs.
Components weighing up to 32t, including steel box columns, have been managed, and both cranes sometimes work in tandem.
Notably, even a 38t mobile crane was lowered into the site’s basement.
UCSF Health Helen Diller Hospital project construction manager Drew Szabat said: “There is very little space available for logistics and material handling. The ongoing hospital operations, combined with the geological challenges and the extremely limited logistical possibilities that San Francisco presents, meant that the two WOLFF 1250 B US cranes were the only machines that could meet the requirements of our project.”
Site preparation began in 2022 to minimise disruption to patient care areas including operating rooms and the emergency department.
Construction activities were coordinated with hospital departments, and protective measures were introduced to reduce noise, dust, and vibration.
A rare procedure will take place near the end of the project, when one WOLFF crane is used to dismantle the other, with regulatory approval required from Cal/OSHA years in advance.
Upon expected completion in 2030, the new building will provide around 83,600m² of floor space and unify several specialist medical services.
