Structural research in UMN's MAST Laboratory

Structural engineering faculty help ensure safe structures

It is often said that the work of engineers goes unnoticed until something goes wrong.  In June of 2021, news was dominated by the account of a condo building collapse in Florida. The collapse of the multi-unit residence in the middle of the night caused multiple deaths. Minnesotans are still mindful of the 2007 collapse of the I-35W bridge. These dramatic incidents bring the public’s attention to the work of engineers, but the greater percentage of their work to protect the health, safety, and welfare of the public takes place out of the public eye.

The first precept in the ASCE Code of Ethics establishes that engineers “first and foremost, protect the health, safety, and welfare of the public.” Engineers protect on many fronts: through establishing codes and standards that govern the design and maintenance of infrastructure, by developing and applying models to simulate and test multiple scenarios and minimize risk, and by studying sensor data to understand what is going on inside or underneath structures.

The structural engineering faculty at UMN help to ensure and improve the safety of concrete structures.

Carol Shield (now Emeritus) and Catherine French have been involved in the development of structural codes and material standards for concrete construction.

Carol Shield served as secretary and then chair for the American Concrete Institute’s (ACI) Committee 440 Fiber Reinforced Polymer Reinforcement. She is currently working with Vicki Brown (Widener University) to prepare the ACI standards and codes for the use of glass fiber-reinforced polymer (GFRP) reinforcement for the internal reinforcement of concrete. The potential of GFRP to alleviate corrosion problems in reinforced concrete cannot be fully realized until standards and codes for its use are established. The next goal is to make the standard available for public comment.

Catherine French is a member of ACI’s Committee 318 Structural Concrete Building Code, which is the standard that governs how concrete structural systems are designed in the US and other regions of the world. French served as chair of the subcommittee on Reinforcement and Development from 2004–2014, during which time she facilitated the development of provisions for adhesive anchors. During the major restructuring of the Building Code Requirements for Structural Concrete, French oversaw the design provisions associated with steel reinforcement, which included properties, durability, and detailing, as well those dealing with anchoring to concrete.

Structures are designed to minimize the risk of potential failure by ensuring the capacity of the structure exceeds the demand. Once a structure is built, maintenance is key to its continued good performance.

Jia-Liang Le works with probabilistic models to address two unique challenges of concrete structures. One is the extrapolation of laboratory test results to full-scale design, and the second is modeling of time-dependent damage and failure of structures. Le and his research group work developed a weakest-link model, based on the concept that a structure is only as strong as its weakest element. 

Identifying damage or wear within a structure is not straightforward. It can be difficult to know what is going on inside a structure, when a triggering event might happen, and what the outcome might be.

Lauren Linderman uses sensors to gather data on structures and to “see” what is happening inside and below surfaces. She and her colleagues recently presented on ten-years’ worth of data collected from thousands of sensors placed on the new I-35W bridge. Her studies are also helping engineers understand the potential of sensors to monitor large structures.

Inspired and innovative engineering for society means apply engineering skills and knowledge to learn from research, to discover new solutions, and to transform our structural systems to be ever more safe, efficient, resilient, and economical.