Located in a prime location, the existing 21-story steel building, originally designed and built in the early 60’s, traditionally dominated the skyline at Westwood’s eastern gateway. In order to attract tenants to this desirable location, plans were envisioned to change the appearance of the building by replacing the old precast spandrels with new floor-to-ceiling glass curtain walls. The steel structure was also going to be renovated using a composite structural system. The then-existing lateral resisting element in the longitudinal direction consisted of steel perimeter trusses rigidly connected to steel columns.

To improve the structural performance of the building during earthquakes, the existing trusses were cut and replaced with reinforced concrete beams. Rebars of the new concrete beam were welded to the flange of the existing steel column. The bottom chord of the existing truss was integrated as part of the bottom reinforcement of the concrete beam. During construction close coordination between our firm and the contractor eliminated temporary shoring. Although the perimeter steel trusses were cut, the gravity system of the structure was maintained during construction. By making use of existing elements, the project saved money and time, and the bracing system of the building was considerably enhanced in the process.