Constructed in 1971, the office building at 180 N. LaSalle Street is a 39-story conventionally-reinforced concrete structure. The roof of the building is composed of multiple levels, a steel-framed sloped section and a narrow perimeter walkway. An original davit system was connected to the steel-framed perimeter walkway. No original roof anchor system was present. Due to the existing davit system lacking adequate design strength to support current code-required loading, the building pursued the replacement of the existing davit system and installation of a new roof anchor system.

Professional Services

Our team was initially engaged to value engineer an alternate roof access system to the more expensive design of another structural engineer. The various roof framing types required multiple davit and roof anchor connection details. The task was complicated, since the existing davit support structure was originally designed for lesser load requirements. Our scheme focused on a roof access system that could be installed from the topside without the need for structural reinforcement. The roof anchor system utilized many of the new davit bases to double as fall arrest points but also used the existing mechanical steel framing and penthouse wall framing to minimize the need for localized roofing removal and replacement.

K&H performed a comprehensive review of the onsite conditions and original construction drawings to develop a cost effective scheme. K&H provided a full set of bid documents including structural and waterproofing detailing. Bidding and construction phase services included compiling bids, holding bid interviews, reviewing shop drawings/submittals, attending weekly project meetings, and providing timely responses and alternate details to various field conditions. K&H worked with Universal Construction Testing to test and provide final certification of the roof access system upon completion of the work.

K&H value engineered a roof access system that was installed at approximately 50% the cost of the previously designed system. Despite the complex roof structure, the careful planning allowed the project to be installed with no change orders and minimal design deviations

Chicago, IL

Roofing Systems
Ordinance & Special Inspections
High Rise

04/2018 - 02/2019

Homa Ghaemi, Senior Principal
Jon Carag, Associate IV