Ann Albright: Knocking down walls to keep walls standing

This piece was written in the fall of 2024 by GRAD 5144 (Communicating Science) student Ekenedilichukwu Anekwe as part of an assignment to interview a classmate and write a news story about her research.

We’ve learned a lot about how to “earthquake-proof” new buildings. Ann Albright wants to enhance the safety of older buildings during earthquakes, too.

    A Ph.D. student in Virginia Tech’s Department of Civil and Environmental Engineering, Albright has a strong background in bridges but shifted focus to buildings in an earthquake research opportunity with faculty member Ioannis Koutromanos in structural engineering and materials.

    Structures built prior to 1960, which were designed to the best standards of the time, are likely inadequate to provide modern levels of safety during a severe earthquake, Albright says, and may be susceptible to collapse. The past 65 years of research have improved engineers’ understanding of earthquakes and how buildings respond to them.

    Albright is designing ways to enhance older structures so that they align better with our current safety standards for earthquakes. This means they should sustain less damage in an earthquake, keeping people safer and making communities more resilient in a post-natural disaster situation.

    Albright uses both experimental tests and computer models to analyze buildings. She hopes to make old buildings stronger and to learn enough to make recommendations for new building codes. Her present work is based on medium-rise building structures (8- to 12-story buildings) built with concrete. She is focusing on the core concrete structural wall, which is built with reinforced concrete. The structural wall is an important component of a building because it resists the forces caused by earthquakes.

    The core concrete structural wall is commonly used for medium-rise buildings because concrete can withstand high compression. This balances the reinforcing steel, which can hold high tension, she said. Albright’s particular focus is horizontal wall systems, as they withstand earthquakes more effectively than the vertical system.

    To conduct her research, Albright uses a scale model that she builds in her laboratory. It is a one-half scale model that represents one story of a midrise building.

    She applies a compressive load that pushes down on the structure to simulate additional walls above the ground floor. She simulates this additional wall weight in the lab and also takes account of it in her model.

    Albright builds this physical model from scratch by using concrete, which contains cement and rocks and a reinforcing cage, together making one cohesive structure. Her walls are built to match the old codes, which were not meant to withstand lateral forces.

    Once the structure is built, Albright applies a horizontal force, which acts to simulate an earthquake. The researchers push the structure at the top and hold the bottom firmly at the foundations; this is similar to how an earthquake shakes a building.

    Albright’s desire is to improve the performance of these old structures by retrofitting. Retrofitting is defined as adding a new modern technology to an existing thing. Specifically, she adds carbon fiber to the walls by using an incredibly strong epoxy or glue. This is not a new technique, Albright explains, but it is under-studied. She considers how these modern updates to an old structure can reliably change its behavior from a brittle, unsafe failure mode to a ductile, safe one.

    Coating the walls with carbon fibers, a reinforced polymer, can slow down the speed of wall breakage, Albright says. This reinforcement results in the structure failing slowly, or in a ductile manner, which gives people time to escape before the building totally collapses. By applying these carbon fiber “band-aids” to old walls, Albright says, she hopes engineers and builders can save lives.