Structural Engineers

In 2009, the leaders of the St. Mark’s Episcopal Church in Capitol Hill recognized a need to update their aging facilities to respond to current requirements while allowing for flexibility and future growth. The final project involved excavating and constructing a new full basement level beneath the existing Parish Hall, removing and replacing the entire first floor with new framing, and constructing an entirely new second-floor space dedicated to offices, all beneath the extents of the existing roof.

Other goals of the client’s included the implementation of sustainable systems, making spaces more welcoming, accessible and available, and providing its staff with a functional, pleasant, safe work environment contained in one location to better integrate them into the daily working of the church.

The Challenge

Structura faced three notable challenges working on this project:

1. The greatest challenge was to deliver a structural design that was both cost-effective and served the needs of the Church. The mix of assembly and office areas required for the new space necessitated a relatively high design live load. To achieve that, the design team worked through several combinations to arrive at a solution that maximized space planning while remaining within the capacity of conventional wood framing.

2. The next challenge was finding a way to support the existing roof while allowing sufficient room for the new 2nd Floor office space while working with the column layout carried up from the floor below.  The existing roof was framed with exposed heavy timber trusses, and the only way to make room for the 2nd Floor was to modify the trusses by removing chord members and replacing with new framing that fitted with the new program. 

3. The final challenge was working with a building originally designed and constructed in the 1920’s. Structura was able to obtain a copy of the original base building design plans, which while helpful were not as detailed as drawings created today. To better understand existing conditions, Structura’s design process included several site visits and field surveys during demolition which did uncover several surprises.

 The Solution

Through a collaborative approach with the architect, E&G Group project manager and the builder, Monarch Construction, the design team arrived at the most economical structural solution. Several pricing exercises vetted each framing option and ensured all space requirements were met.

The most challenging structural task was the modification of the existing roof trusses.  Keeping the original form was never an option simply because the new 2nd Floor space would be in conflict with the web and bottom chords. Structura therefore developed a scheme that used the columns from below to support the top chords of the trusses. The columns were located in a way that did not require reinforcement of the existing members while accommodating the offices below.

 The Takeaway

– Time spent surveying and understanding existing conditions is well worth it.  The more problematic conditions are identified in the beginning of the project, the better.

– Work closely with other consultants and trades to determine the limitations for the extents of the structure. 

– Make sure there is an understood protocol among all design team members and the Client for what happens when unforeseen conditions are discovered and have an impact on assumptions.

Through a team approach, a proven process and creative problem-solving, Structura and the rest of the design team was able to deliver a final project that met the client’s goals of preserving their historic property while renewing the existing space, enhancing their mission and providing for the future.