Located within walking distance of the popular Ballston Quarter shopping mall, 4100 North Fairfax Drive is an impressive 13-story office building that stands tall above a 5-level below-grade parking garage. Completed in 2001, the building is not just a workspace; it features a modern fitness center and locker rooms. 

However, cracks in tile and finishes, and excessive deflections of the fitness center and locker rooms floors raised concerns regarding the structural integrity of the floor system. Significant cracks appeared on the underside of the slab, and large gaps became apparent beneath the Concrete Masonry Unit (CMU) walls.  

In response to these concerns, the BECS team was called in to conduct a meticulous evaluation of the fitness center’s floors and walls. Our mission? To uncover the underlying issues, propose a range of effective repair solutions, and devise a strategic plan to tackle the various cracking and separation problems.

We carried out a detailed investigation, starting with a thorough visual inspection to identify cracking patterns and identify possible signs of structural failure, and obtain measurements to document the conditions. After reviewing the existing building plans and repair histories, we performed non-destructive testing of the CMU walls and concrete floor slab used a Ground-Penetrating Radar (GPR) to detect and confirm the placement and installation of steel reinforcement in the concrete slab and performed calculations to identify structural deficiencies. Our findings revealed that the reinforcing bars were not properly installed and structurally deficient, and the downward deflection of the slab exceeded industry standards. Additionally, cracks surrounding the columns raised potential structural concerns that needed immediate and effective solutions.

Action was taken to stabilize the concrete floor slab and re-establish its structural integrity.  A supplemental concrete beam was installed in conjunction with external carbon-fiber reinforcement.  After the stabilization efforts were completed, a deflection gauge was installed to monitor and ensure the safety of the slab, and the finishes in the locker room and fitness center were restored. 

Addressing these issues is not only critical for the building’s safety but also for ensuring its structural integrity and functionality for years to come. Our proposed strengthening repairs fortified the structure, making sure that this vibrant office building continues to stand proud in the heart of North Fairfax Drive. With BECS on the job, you can trust that the future of this property is in capable hands!