Project Description: The hospital renovation involved installing multiple Magnetic Resonance Imaging (MRI) machines on the third floor of their building in downtown Chicago. The existing floor was not designed for such heavy loading as these machines weigh upwards of 25,000 lbs. The structure consisted of a 3" slab supported by joists and beams. Structural steel was installed at the permanent MRI locations but the floor needed to be strengthened along the corridors where the MRI machines would be rolled into their final location.
Solution: The floor area to be strengthened was deficient in both shear and flexure. The beams were fine but the joists needed to be strengthened. The machines were going to be hoisted in through an opening in the facade and rolled to their final location. FRPs were used to strengthen the joists in shear and the slab was wrapped with FRPs to improve for both negative and positive moment capacity. The underside of the slab had FRPs applied in strips while the slab topside had a continuous full coverage application.
Summary: This project was a classic case of "change of use" of an existing structure. An alternative could have been the installation of steel but this would have been time consuming and perhaps more expensive than using FRPs. Fibrwrap® was able to mobilize quickly and get the work done despite all the other trades and encumbrances. In fact the hospital went ahead and strengthened the underside of the fourth floor because once the mechanical trades had completed their work it would have been impossible to access the joists and slab.
