The Thin-walled Structures group, and Professor Schafer, work across these broad categories of research:
|Structural Engineering||Structural Stability||Structural Reliability|
|Thin-walled Structures||Cold-Formed Steel Structures||Steel Structures|
|Experimental Mechanics||Computational Mechanics||Biomechanics|
|Earthquake Engineering||Resilience/Resilient Cities||Future Energy Structures|
|Structural History||Structural Art||Building Design/Const.|
Structural Engineering is the broad field in which the group works. Our efforts generally focus on building structures, but the group has worked on bridges, towers, racks, cars and numerous other structural systems. Professor Schafer is a Fellow of the American Society of Civil Engineers – Structural Engineering Institute.
Structural Stability is the consideration of buckling and geometric nonlinearity in the performance of structures – our group contributes in this area extensively and Professor Schafer is a past Chair of the Structural Stability Research Council.
Structural Reliability is the consideration of uncertainty in the design of structural systems, our group has worked in this area primarily in relation to cold-formed steel framing and system reliability, with works such as this one. Recognizing the need for robust statistical characterization of inputs we have performed fundamental work on imperfections and residual stresses in cold-formed steel members to better inform stochastic models and reliability studies.
Thin-walled Structures are the class of structures in which stability and geometric nonlinearity of the components that form a section typically drive the response. The group works broadly in this area and Professor Schafer is past North American Editor of the journal Thin-walled Structures. The team has worked on thin-walled structures comprised from plastics, aluminum, cold-formed steel, hot-rolled steel, stainless steel, wood, bone, and more.
Cold-formed Steel Structures are comprised of lightweight steel members formed to shape at room temperature from coil steel typical 1-3mm thick and are used in buildings, racks, metal building systems, support structures and more. The group has authored large portions of the governing U.S. standard for cold-formed steel structures and originated the Direct Strength Method of design (review article one and two). Professor Schafer is the Founder and Director of the Cold-Formed Steel Research Consortium. He is the past Chair of the Cold-Formed Steel Engineering Institute and the ASCE Committee on Cold-Formed Steel. He serves on the American Iron and Steel Institute committees that create the U.S. Standards for cold-formed steel design. He Chairs the ASCE 8 committee that creates the standard for Cold-Formed Stainless Steel Structural Members.
Steel Structures are comprised of heavier rolled shapes and plate are are used widely in buildings, bridges, and the broader civil infrastructure. Professor Schafer serves on the American Institute of Steel Construction committee that creates the U.S. standards on hot-rolled steel design and is Vice-Chair of the committee on stainless steel structural members.
Experimental Mechanics are foundational to the study of thin-walled structures and the group maintains a testing laboratory that has performed studies on cold-formed steel walls, joist-stud assemblages, beam-columns, columns, beams, fastener assemblages, and materials testing. We developed a unique laser scanning rig for geometric imperfection characterization and a completely unique multi-axis testing rig for full wall testing under multiple actions (compression, shear, out-of-plane bending).
Computational Mechanics that encompass geometric and material nonlinearity are necessary for the study of thin-walled structures. Our group is best known for its contributions to cross-section elastic stability analysis and the application of the finite strip method and development of the constrained finite strip method. See CUFSM.
Biomechanics is a collaborative effort for our group. We have worked with radiologists to characterize the role of cortical bone slenderness in stability-induced hip fracture, with biomolecular engineers to elucidate the role of stability in actin filaments in living cells, and with mechanical engineers to develop methods to steer slender needles through tissue for surgery.
Earthquake Engineering is critical to the advancement of structural engineering, and our group has worked extensively to advance the seismic design of cold-formed steel structures. We performed the first full-scale shake table test on a cold-formed steel framed building, authored a major rewrite of the AISI S400 Specification, and continue to work extensively to advance our understanding of buildings as complete systems – including the interaction of lateral and gravity systems as well as vertical and horizontal lateral force resisting systems. The group is involved in seismic performance-based design efforts and considers earthquake engineering as an important starting point for advancing multi-hazard engineering and building structural system design in general. See CFS-NEES, SDII, and more.
Resilience/Resilient Cities are broad and increasingly important areas that address the ability of a system (material, building, city) to adapt and recover from shocks and hazards. Our group’s expertise begins at the structural level and relates to the selection of systems for buildings and structures that are more robust to hazards and damage; however, our interests are broader and include collaborations with those interested in (a) the broader infrastructure that forms the physical backbone of cities and (b) the social-technical interactions that comprise community-level resilience.
Future Energy Structures consist of the infrastructure to support alternative energy solutions: solar support structures, and wind turbine towers are two examples that our research group has expertise and research efforts within. In both cases the critical supporting structure is thin-walled and our groups expertise can be used to optimize and improve efficiency in these important structures. The group is interested in other alternative energy structures and ideas, including the solar chimney.
Structural History is an important aspect of structural engineering education and Professor Schafer has specific interests in this area. He has collaborated with the National Park Service on covered wooden bridges and performed independent research on the contributions of John Wellborn Root to the development of the steel skeletal skyscraper in Chicago.
Structural Art is a means to critique our built environment, and through assessment of social, scientific, and symbolic significance determine the great works of structural engineering. Professor Schafer teaches about Structural Art in the course Perspectives on the Evolution of Structures. The notion that full evaluation of structural success requires examination across multiple criteria (e.g. social-economy, scientific-efficiency, and symbolic-elegance) was first provided to Professor Schafer as an undergraduate at the University of Iowa and formed the genesis for a life-long interest in structural engineering not as only “structural response,” but the role of structures in resilience, sustainability, disaster mitigation and a variety of related areas.
Building Design is an engineering design process focused on creating a safe final form given extreme uncertainty and the inability to prototype and test at scale. Professor Schafer has a deep interest in this area as an educator and an engineer. Building Construction is evolving with the growth in panelized and modular construction. Professor Schafer is keenly interested in the application of thin-walled structures growing from the member (e.g. a thin-walled lipped channel) to the subsystem (e.g. panel or module) to the complete structure (e.g. the punched tube lateral system for high-rise buildings).