Ashley P. Thrall

Myron and Rosemary Noble Associate Professor

of Structural Engineering

University of Notre Dame
Department of Civil and Environmental Engineering
and Earth Sciences
Ashley P. Thrall



CAREER: Transitional Bridging: From Rapidly Deployable Disaster Relief to Permanent Infrastructure Solutions


Funded by a National Science Foundation Faculty Early Career Development (CAREER) Program award, ongoing research efforts are building a theoretical framework for transitional bridging - bridges that can be rapidly deployed for immediate disaster relief and can be transformed in-situ for higher load capacity to support long-term, sustainable development. Following natural and anthropogenic hazards, rapidly deployable bridges are critical to restoring vital transportation arteries. The long recovery times following the 2010 Chile earthquake and tsunami demonstrate the need for bridging solutions that can provide an immediate response but also serve as permanent infrastructure. To this end, the project will test the hypothesis that novel adjustable connections can increase efficiency of rapidly erectable bridging systems by enabling a diversity of structural forms which can more effectively carry load using less material. The research plan will also test the hypothesis that novel adjustable modules can provide transitional capabilities. The efficiency of the transitional bridging framework which integrates the adjustable connections and modules will be verified numerically and experimentally. For more information on this project, see the project-specific website.


 A New Approach to Accelerated Fabrication of Steel Bridges: Design, Optimization, and Demonstration


With support from the Indiana Department of Transportation - Joint Transportation Research Program and in collaboration with HNTB Corporation, this project will develop and demonstrate a new approach to the accelerated fabrication of resilient steel bridges. Research objectives include: (1) Design and build a simply-supported and a multi-span continuous demonstration bridge; (2) Measure the dead and live load strains of the demonstration bridges as experimental evidence demonstrating behavior; and (3) Develop and optimize a kit-of-parts system to facilitate adoption.


An Innovative Approach to Concrete Confinement Reinforcement


This research is investigating a new approach to confinement reinforcement. This innovation has the potential to improve the ductility and strength and accelerate the fabrication of seismic precast concrete columns. While the research will focus on confined concrete columns, results will be relevant to boundary regions and plastic-hinge zones of beams, walls, and piers.


A Precast/Prestressed Concrete Institute Daniel P. Jenny Fellowship is providing support to experimentally investigate the behavior of the confined columns under axial load. 


Funding from the American Concrete Institute Concrete Research Council is supporting experimental testing of the columns under combined axial and reversed-cyclic lateral loads. 


Assessment of Bridges Subjected to Vehicular Collision


Funded by the Indiana Department of Transportation - Joint Transportation Research Program, the aim of this project is to understand the impact of vehicular collision on the behavior and load carrying capacity of slab-on-steel-girder bridges. Research will include (1) performing non-destructive field testing using Digital Image Correlation, (2) developing validated numerical models, and (3) performing parametric investigations to extend results to other loadings and bridge geometries. Research will culminate in analysis recommendations and assessment guidelines for bridge inspectors to evaluate damaged bridges for repair.


Novel Deployable Origami Shelters with Integrated Energy Planning and Management


Funded by the US Army Natick Soldier Research, Development and Engineering Center, a novel deployable origami shelter with integrated energy planning and management has been developed. This research was motivated by the rising priority for reducing fuel consumption for heating and cooling military shelters. To address this need, the Kinetic Structures Laboratory (KSL) has designed a concept for a folding, rigid wall structure inspired by the art of origami. It is comprised of sandwich panels which provide a high strength-to-weight ratio and thermal insulation. The structure folds to a compact state for transportability. To develop this concept, the KSL has performed structural analysis according to design loads, and optimized the shape for structural performance and energy efficiency in heating and cooling. The concept has been demonstrated through the erection of a full-scale prototype. To further investigate behavior of this structure, the KSL has performed experimental testing on a half-scale prototype (including material testing according to ASTM standards, component testing on a single panel, testing during deployment, and testing of the erected prototype). The KSL is collaborating with mechanical and electrical engineers who are testing thermal behavior of the shelter and developing a control system for heating and cooling the shelter with the aim of conserving fuel consumption.


See a feature website and video here.



Prefabricated High-Strength Rebar Systems with High-Performance Concrete for Accelerated Construction of Nuclear Concrete Structures


This project involves innovative research that offers the promise of dramatically reduced field construction times and fabrication costs for reinforced concrete (RC) nuclear structures through: 1) high-strength steel deformed reinforcing bars (rebar); 2) prefabricated rebar assemblies with headed anchors; and 3) high-performance concrete. The focus is on shear walls, their connections/joints, and around large penetrations/embedments because they are the most common lateral load-resisting members in non-containment nuclear structures. Specific research goals are to: A) develop transparent limit/cost-benefit frameworks; B) develop an optimization methodology for design; C) conduct experimental evaluations of structural members, member-to-member/foundation joints, splices, anchorages, and penetrations; D) develop validated numerical simulation models; E) develop validated design procedures/tools/criteria; and F) develop field procedures that are consistent with current methods. The experiments to be used for the validation of the design methods and simulation models include testing of: 1) high-strength materials; 2) headed rebar details (e.g., anchorages); 3) shear-wall-to-foundation joints under pure shear; and 4) multi-story shear walls under service, thermal, and seismic loads (combined shear and flexure). This project is funded by the Department of Energy. It is a collaborative effort with Dr. Yahya Kurama (University of Notre Dame, Lead), Dr. Scott Sanborn (Sandia National Laboraties), and Mr. Matthew Van Liew (AECOM).


See the dedicated project website here.


Robust Design Optimization of Modular Lightweight Structures


In collaboration with the Universite libre de Bruxelles, the KSL is investigating modular design through structural optimization. This research is focusing on topology optimization (i.e., member layout) of modular truss structures.


Re-Conceptualization and Optimization of a Rapidly Deployable Causeway


In collaboration with the US Army Engineer Research and Development Center (ERDC), a rapidly deployable, modular, floating causeway was re-conceptualized and optimized. Prior to the collaboration, ERDC developed a prototype of the causeway (comprised of aluminum modules joined by compliant connections and supported by pneumatic floats) in response to the demand for a lightweight, air-liftable, quickly emplacable causeway. ERDC identified eliminating the heavy and complex compliant connections as a potential area for improvement. To eliminate these compliant connections, the KSL has re-conceptualized and optimized this design so that a desired superstructure flexibility (that takes advantage of buoyancy while meeting deflection limits) is achieved.


Transitional Sheltering and the Universal Scissor Component


In collaboration with the Vrije Universiteit Brussel (VUB), the KSL investigated the behavior of scissor-like elements as components for transitional shelters - shelters which can be rapidly deployed for immediate disaster relief and later reconfigured to support long-term recovery and reconstruction. Research to date has included parametric finite element modeling and experimental validation using digital image correlation and tracking of a deployable scissor arch (see video below). Research activities have also included optimizing the universal scissor element - a multi-configurable scissor element which has the potential to improve the transitional capacity of scissor shelters. A parametric evaluation of the scissor arches provided further insight for design.