The 22-story high-rise tower is enclosed in a combination of granite cladding panels, aluminum strip windows, and a unitized curtain wall system. The granite panels and strip windows are attached to a modular steel truss system, with each unit comprising an area one structural bay wide and one floor high.
RRJ was retained by the property manager to conduct a Critical Examination of the exterior walls of tall buildings as required by the Chicago Facade Ordinance. During one such review period, RRJ’s close-up examination from suspended scaffolds identified several conditions requiring repair in order to meet the facade ordinance safety requirements.
Subsequently, RRJ was retained to develop repairs to resolve these conditions. This task required reviewing relevant portions of the building’s original architectural and structural drawings, design calculations and shop drawings for the curtain wall system, strip windows, granite panels, and steel truss support system to develop an understanding of the design intent for the exterior building envelope.
The repairs designed by RRJ included the addition of supplemental anchors to granite panels deemed repairable, epoxy injection of certain types of stone cracks, replacement of extensively damaged granite panels, and replacement of all broken window glass. The granite panel replacement work and supplemental anchorage installations required the development of new stone anchors that could engage the supporting steel trusses and provide resistance for both wind pressure and suction loads. Laboratory testing of the new anchor design by RRJ confirmed the structural capacity of the anchor system and demonstrated its feasibility for use in repair construction.
RRJ provided bidding assistance to secure competitive repair bids and performed construction administration services.
