Rodrigo Gonçalves, Ph.D., Assistant Professor at NOVA University Lisbon is the 2017 recipient of the MAJR Medal.

The McGuire Award for Junior Researchers (MAJR Medal) has been established in honor of the late Professor William “Bill” McGuire, a long-term member of SSRC, who emphasized that state-of-the-art research is instrumental to improve the quality of stability design. The award recognizes the research activity of the candidate in a period not exceeding nine years after obtaining his/her Ph.D. degree.

Gonçalves will receive the award and deliver a presentation on his recent research activity at the 2018 SSRC Annual Stability Conference in Baltimore, Maryland.

The following jurors collaborated to select Gonçalves as the recipient of the 2017 award:

  • Larry A. Fahnestock, University of Illinois at Urbana-Champaign
  • Todd A. Helwig, University of Texas at Austin
  • Daniel G. Linzell, University of Nebraska

2017 Annual Stability Conference Presentation

Session S8 – Stability of Wall Systems
Thursday, March 23, 2017
3:00 pm

SC Wall Compression Behavior: Interaction of Design and Construction Parameters

Modular steel-plate composite (SC) construction involves pre-fabricated steel modules that are transported to the site, assembled and then filled with concrete. The construction parameters (concrete casting height, etc.) and casting sequence for these modular walls may vary, leading to small but permanent stresses and deformations (or imperfections). These geometric imperfections, combined with the variations in SC wall design and detailing parameters (such as steel and concrete grades, tie bar spacing, faceplate slenderness), could influence the compressive behavior and capacity of the SC walls. This paper explores the effects of imperfections and design parameters on the axial compression capacity of the SC walls. The analysis procedure involves simulating the effects of initial imperfections, construction sequence, etc., followed by axial compressive loading up to failure. Parametric studies are conducted to evaluate the effect of variability in steel grades, faceplate slenderness, and height of concrete pour on the compression behavior of SC walls. The analysis results indicate that the compression behavior of SC walls (for nuclear facilities) is dominated by concrete. Faceplates for SC walls meeting the requirements of AISC N690s1 perform adequately (yield in compression before buckling) for concrete pour heights up to 30 ft. However, the concrete pour height and plate slenderness affect the faceplate waviness tolerance, and need to be addressed in the analysis. The performance of specimens with 36 ksi faceplates is acceptable for the current configuration of ties, but needs to be explored for different configurations. Future studies will further evaluate the effects of tie spacing and configuration, and concrete grades.

Saahastaranshu R. Bhardwaj and Amit H. Varma, Purdue University, West Lafayette, IN

2017 Annual Stability Conference Presentation

Session SS2B – Technical Presentations: Stability at Elevated Temperatures
Tuesday, March 21, 2017
3:15 pm

Stability Analysis of Steel Columns under Cascading-Hazard of Earthquake and Fire

In this study, a nonlinear finite element formulation is developed and utilized to perform stability analysis of W-shape steel columns subjected to non-uniform longitudinal temperature profiles in the absence or presence of inter-story drift, representing residual drift following an earthquake. This formulation takes into account the residual stress distribution in steel hot-rolled W-shape sections, initial geometric imperfections in the steel columns, non-uniform longitudinal temperature distribution, and temperature-dependent material properties. The results indicate an excellent agreement with available strength design equations of steel columns at ambient and elevated temperatures. A set of equations is then proposed to predict the critical buckling stress in steel columns under fire and fire following earthquake considering residual drifts and non-uniform longitudinal temperature distributions. The proposed equations can be implemented to investigate the performance of steel structures under fire and fire following earthquake considering stability as engineering demand parameter.

Mehrdad Memari and Hussam Mahmoud, Colorado State University, Fort Collins, CO

2017 Annual Stability Conference Presentation

Session S9 – Stability of Shells
Thursday, March 23, 2017
4:15 pm

On the Investigation of the Most Critical Shape Imperfections for Wind Turbine Tower Shell Structures

Among the many technical goals of today’s wind energy industry is to develop solutions for taller wind turbine towers. The increase in height of wind turbine towers is imperative to achieve goals of efficiency and competitiveness, as the wind profile is stronger at higher heights. However, making higher wind turbine tower structures poses numerous challenges to structural engineers. One of the biggest challenges for thin cylindrical shells, such as tall wind turbine structures is their high sensitivity to geometric imperfections. It is expected that the capacity of this type of shells can drop significantly in the presence of geometric imperfections. This paper is studying this sensitivity by investigating the worst shape imperfection for a specific wind turbine tower geometry. For this investigation, the elastic modes of the structure are utilized either as individual shapes or as the basis for shape combinations, in order to find the worst initial geometric imperfection shape.

Kshitij Kumar Yadav and Simos Gerasimidis, University of Massachusetts, Amherst, MA;  Jens Lycke Wind, Vestas Wind Systems A/S, Aarhus, Denmark