Holy Family Hospital - Nuclear Medicine Addition
Daigle Engineers, Inc. was the structural engineer for the Nuclear Medicine Addition at the Holy Family Hospital in Methuen, MA. The addition was a five story steel building with 65,000 square feet of floor space and a price tag of approximately $22 million.
One of the main challenges to this project was dealing with the fact that the proposed building was to abut four existing buildings which were designed by various engineers and constructed by different contractors over the course of several decades. Each floor plate had a different layout due to the varying perimeter configuration of the abutting buildings. In order to minimize considerations of Chapter 34 (renovations to existing buildings) of the Massachusetts State Building Code, the new structure was kept seismically separate from the existing structures. RAM Steel was used to aid in the structural steel design of this complex addition. Foundation strap beams were employed to support column loads directly abutting the existing structures. One section of the addition had to bridge across a three lane access drive to the ambulatory day care entrance. This was done by employing long span composite steel girders with composite concrete slabs.
Another challenge on this project was the fact that the floor to floor elevations were very tight (i.e. 11'-0") in order to match up with the existing floors. This required that shallow beams be employed. Use of concrete slabs with composite, cambered beams allowed the intermediate 27' beams to be 8" deep while maintaining deflection control.
Our office also had to locate over 100 holes to be fabricated in the steel for installation of the sprinkler system as close as possible to the underside of the floor deck. Due to the shallow beams, the locations of these 4" holes were critical to the proper performance of the floors system.
Ambitious Project Schedule:
After a delay in the schedule the project went into fast track design. Structural "design development" was completed and CD's had been started when the project shifted into high gear. Foundation drawings were developed in advance of the superstructure and numerous assumptions had to be made with regard to the architectural design since the structural drawings were being advanced well ahead of other disciplines. Due to problems with the mechanical design phase of the project the mechanicals were changed to a "design build". This further complicated the structural design since we were already in the shop drawing phase. The large pre-engineered/fabricated penthouse that was planned for the roof was eliminated and the structure had to be revised to support isolated 60,000 pound HVAC packages which shifted the loads on the supports enough to warrant a redesign of the roof structure. Other changes required that the main chevron bracing for the building be adjusted to suit last minute door locations. This altered the foundations which were already under construction.
Fortunately, the hospital had fairly accurate construction drawings of the surrounding buildings. This along with the extensive field investigations and measurements made prior to and during the design phase of this project allowed the construction to proceed with very few field conditions/change orders.
The building at the time of this writing had all of the structural steel in place along with the composite floor slabs. Exterior walls were in place, awaiting the window and window wall installation.
Steffian Bradley Architects, Inc.
Payton Construction Corp.