Reinforcing Transparency and Resilience
155 North Wacker is a prominent Class A office tower in downtown Chicago, distinguished by its dramatic 45-foot-tall covered arcade and stone-clad lobby. From the beginning, the building’s design emphasized transparency. A cable-supported “netwall” of oversized glass panels blurred the line between exterior and interior, presenting the lobby as a luminous extension of the street. Over time, however, the netwall system began to fail. Excessive deflection caused panels to break and the walls to bow significantly inward, compromising both performance and appearance.
The building’s owner seized this challenge as an opportunity to reinforce the original design intent while implementing a more resilient solution. HED was engaged to develop a replacement glass wall system that could meet the building’s ambitious architectural goals while addressing the technical risks of construction in an occupied tower.
The solution features an all-glass wall system enclosing monumental 50-by-50-foot openings. Ultra-clear glass panels are supported by single-piece, full-height structural glass fins, eliminating the need for cables and restoring the clean geometry of the façade. At the time of construction, these fins were the tallest single-piece glass fins in North America, underscoring the innovation and precision required to achieve the design. Hardware connections were kept intentionally discreet. On the exterior, the surface reads as a pristine plane of glass, uninterrupted except for the minimal entrance portals. On the interior, polished metal portals reflect the arcade and lobby, reinforcing the elegance of the design while highlighting the play of light on glass and stone.
The renovation also allowed the owner to reconsider building signage. Working with HED’s experiential graphic design team, a strategy was developed to balance visibility with subtlety, ensuring that branding would complement rather than compete with the architecture. Custom dimensional polished metal signs, paired with razor-thin entrance portals, reflect the crystalline quality of the glass façade. At night, backlit signage enhances visibility along both Wacker Drive and Randolph Street while preserving the building’s minimal, transparent character.
By replacing the aging netwall with an innovative structural glass system, the project restored the integrity of one of Chicago’s most distinctive towers. The intervention reasserts transparency as the defining quality of 155 North Wacker, maintaining the building’s prominence while advancing its resilience.
It demonstrates how thoughtful design and engineering can respect original architectural intent while bringing forward new levels of technical achievement and long-term performance.
