Ashley Thrall

University of Notre Dame | ND · Department of Civil and Environmental Engineering and Earth Sciences

This paper experimentally investigates the axial load behavior of square reinforced concrete columns confined using dual-phase high-strength (100 ksi [690 MPa] yield strength) steel coiled strips. Two phases of testing were conducted on reduced-scale specimens (8 × 8 in. and 10 × 10 in. [203 × 203 mm and 254 × 254 mm]). Varied parameters include co...

Vehicles often collide with girders of low-clearance bridges, yet there is a knowledge gap in understanding the behavior of damaged steel girders. This paper addresses this gap by performing non-destructive field testing on four damaged steel girder bridges. The focus is on two- and three-span continuous multi-girder steel bridges for which an exte...

The objective of this paper is to present a numerical investigation of the redundancy of steel truss bridges composed of novel modular joints when subjected to the sudden loss of diagonal members. The modular joint - a prefabricated steel nodal connector composed of flat web plate welded to flat and curved cold bent flange plates - represents a new...

This paper describes an experimental investigation on the use of high-strength steel and high-strength concrete to reduce the required reinforcement areas in nuclear shear walls. Two squat rectangular walls with uniformly distributed reinforcement (i.e., without boundary regions) and rectangular penetrations commonly found in nuclear power plant co...

This paper presents the behavior of the Delaware River Bridge, measured via the non-contact photographic measurement technique digital image correlation (DIC), as the bridge was repaired through vertical jacking and post-tensioning. Constructed in 1956 by American Bridge, the Delaware River Bridge is a continuous steel truss joining the New Jersey...

This paper experimentally and numerically investigates the service and ultimate behavior of adjustable bolted steel plate connections—slip-critical, splice plate connections that can join wide flange sections at a range of angles as well as adjust in situ to achieve additional angles or compensate for erection and fabrication tolerances. The connec...

This paper presents an experimental investigation of bolt behavior in adjustable bolted steel plate connections during field installation and a numerical finite-element (FE) parametric investigation of the impact of (1) bolt diameter; (2) plate thickness; and (3) member flange thickness on the strains induced in the plates and bolts during field in...

Modularity, a design philosophy in which a structure is comprised of identical components called modules, offers economical advantages as the modules can be mass produced in high quality controlled facilities. Prior research investigated structural optimization as a means of improving modular design, focusing on optimizing separately (i) the module...

Digital image correlation (DIC)—a photographic measurement technique that relies on pattern recognition to calculate displacements and strains—can provide unprecedented data on bridge behavior, strength, and overall condition. A major challenge in using DIC to measure full‐field strains and displacements (as opposed to point tracking) in bridges is...

Prefabrication of steel reinforcement (rebar) assemblies can reduce construction costs and time while improving fabrication quality and safety. However, changes in rebar spacing (i.e., shifting of rebar from their original tied positions) can occur during the transportation and final placement of these assemblies, potentially leading to violations...

This paper describes an experimental evaluation on the isolated and combined effects of high-strength concrete and high-strength steel on the behavior of stocky reinforced concrete structures. Monotonic lateral load tests were conducted on four cantilever deep beam specimens, which represented slices along the length of a prototype stocky shear wal...

Including stability in truss topology optimization is critical to avoid unstable optimized designs in practical applications. While prior research addresses this challenge by implementing local buckling and linear prebuckling, numerical difficulties remain due to the global stability singularity phenomenon. Therefore, the goal of this paper is to d...

This paper presents a bolted steel plate connection to join steel members at a range of angles with the capability of adjusting in situ to accommodate additional angles or tolerances through cold bending. The connection features plates that are prebent (cold bent via a press brake) to defined angles, and then further cold bent during field installa...

Previous numerical research has shown that high-strength steel reinforcing bars (rebar) combined with high-strength concrete can increase the lateral strength of stocky (i.e., low height-to-length aspect ratio) reinforced concrete (RC) walls in noncontainment safety-related nuclear structures as well as nonnuclear building structures. However, ther...

Stocky reinforced concrete (RC) walls with low height-to-length aspect ratios stand to benefit greatly from high-strength steel and concrete because the lateral load designs for these walls are governed mostly by strength, with reduced demands for ductility, which is compatible with the reduced strain capacities of high-strength materials. This pap...

Modularity in structural engineering offers significant cost advantages since identical components can be mass-produced in high quality-controlled facilities. While prior research has investigated the optimization of modular structures, this work is limited to the module topology periodicity, leading to solutions where some structure parts remain i...

With the recent American Association of State Highway and Transportation Officials bridge design code acceptance of cold bent fracture-critical and nonfracture-critical plates and the increasing use of cold bending by the bridge industry, there is a need to better understand and predict residual strains in cold bent steel. However, measuring residu...

This paper presents a new strategy for modular steel construction: an adjustable module. Existing rapidly erectable, steel panelized bridge systems (e.g., Bailey, Acrow, Mabey-Johnson) have limited material efficiency (span squared per weight) as they are comprised of rigid modules in a girder-type configuration. This paper addresses this limitatio...

Rapidly erectable, folding structures comprised of sandwich panels offer light-weight, energy efficient sheltering solutions. Field implementation requires better understanding of the impact of the erection conditions and fabrication errors on behavior, including (1) out-of-level ground conditions, (2) number/location of ground anchors, and (3) fab...

This paper investigates the load-bearing capability of sandwich panels (composed of fiber-reinforced polymer faces and a foam core) connected by aluminum hinges in an origami-inspired deployable structure intended for temporary sheltering. The structure is studied (1) during deployment (loaded under self-weight only), and (2) as both individual and...

Lightweight, thermally insulated, temporary shelters are essential for disaster relief and military operations. To minimize cost and increase sustainability, it is advantageous to reduce wasted material in manufacturing these shelters. This paper investigates quilt patterns – designs of interlocking geometric shapes – as inspiration for structural...

Panelized bridge systems (e.g., Bailey, Mabey Johnson, Acrow) are intended for girder-type bridges and have been implemented for military, civilian, and disaster relief applications. Design challenges, however, include material efficiency (span squared per number of panels), lateral bracing, and achieving longer spans. These challenges are addresse...

This paper discusses the impact of hinged connectors (a common connection in folding structures) on the behavior of sandwich panels (with fiber-reinforced polymer faces and foam core). A sandwich panel is subjected to uniform loading and tested when restrained by hinged connectors in compression and in tension. The measured results are compared to...

In a dynamic and evolving society there is a need for temporary and mobile structures. For this, deployable scissor structures – structural mechanisms that can transform from a compact state to a fully deployed configuration – are suitable. However, this transformational capacity complicates the design process since there is a strong interaction be...

Origami can be a source of inspiration for rapidly deployable, rigid wall shelters. Folding panels comprised of sandwich panels will result in a lightweight, transportable design. The design of connections between panels is critical to the overall structural performance, but can pose a major design challenge. This paper investigates the implementat...

Deployable scissor structures are well equipped for temporary and mobile applications since they are able to change their form and functionality. They are structural mechanisms that transform from a compact state to an expanded, fully deployed configuration. A barrier to the current design and reuse of scissor structures, however, is that they are...

For military and disaster relief housing, rapidly deployable shelters must be lightweight, be packaged in a small volume for transportability, and be erected without heavy lifting equipment. A critical design criterion is also energy efficiency in heating and cooling. To meet these priorities, the research team has utilized origami as inspiration f...

Rapidly deployable shelters are critical for housing on forward operating bases and for relief following natural or anthropogenic disasters. In addition to meeting structural performance criteria specified by design code, key design priorities include a low self-weight (preferably being person-portable), deployability (i.e., capable of being packag...

Disaster relief shelters must be transitional, meaning capable of serving an affected community from emergency, to rehabilitation, to reconstruction. Deployable scissor structures are well-suited for this application since they are lightweight, can be compactly packaged, and have a high volume expansion ratio. Their constitutive parts can be reused...

Deployable scissor structures can transform from a compact bundle of elements to a fully expanded configuration. Due to this transformational capacity there is a mutual relation between the geometry, the kinematics and the structural response of the scissor system, resulting in a relatively complex design process. In order to understand how geometr...

Lightweight, deployable structures are critical for temporary sheltering in military or disaster relief operations. For these purposes, rigid wall shelters are preferable to soft wall (canvas) solutions since they provide enhanced thermal insulation. However, challenges in implementing rigid wall solutions include transportability and erectability....

Rapidly deployable shelters, which can be packaged small but offer a high volume expansion ratio, are a critical asset for forward operating bases and can also be effective for disaster relief. Origami-inspired deployable shelters provide significant design advantages, including that (1) the rigid folded plates of these structures provide enhanced...

Determining the global shape of a deploying structure and the section profiles of its members is a challenging design problem. Geometry, meaning the lengths and relative angles of members, is critical to achieving stable deployment to a desired span, while the design must also satisfy structural capacity demands at each stage of deployment. This pa...

There is an increasing demand for rapidly deployable causeways that can provide access from ship-to-shore for military and disaster relief operations. Existing systems have major limitations including only being transportable and emplaceable by large strategic sealift vessels, having high weight and packaged volumes, and requiring intensive on-site...

Origami, the art of paper folding, is becoming increasingly recognized as a fruitful area of inspiration for engineering design and research. The state-of-the-art in origami engineering ranges across disciplines. At the structural scale, origami-inspired structures offer particular advantages for rapidly deployable shelters since (1) in the deploye...

Portable and rapidly deployable bridges are critical for providing access routes for troops during military operations and for restoring vital lifelines for communities affected by large-scale disasters. This paper reviews the history and the state of the art in portable and rapidly deployable bridge technology, primarily for U.S. systems. Four typ...

This paper presents a technical, historical, and aesthetic study of the Maria Pia Bridge over the Douro River in Porto, Portugal which was designed and built by G. Eiffel and Cie. between 1875 and 1877. Through these analyses, this paper demonstrates the significance of this bridge due to its (1) economy as shown through the design competition, (2)...

Linkages have been widely used in machines and deployable structures, but these mechanisms have rarely been employed in the design of movable bridges. This paper explores the use of linkages both to actuate the kinematic motion and to serve as structural elements of movable bridges. First, the design methodology for these forms is presented which i...

This paper explores a novel form for movable bridges which uses linkages as the main kinematic and structural elements. The proposed linkage-based movable bridge form was designed through 1) physical shape-finding, 2) generating a parametric model and kinematic equations, and 3) multi-objective structural optimization for minimum self-weight and mi...

Finding efficient forms and section profiles for a deploying structure is a challenging design problem traditionally approached through trial and error. Alternatively, heuristic search algorithms can be used to pursue an optimized geometry and design the section profiles. This paper proposes a methodology for the design and optimization of a deploy...

Between 1875 and 1877, G. Eiffel & Cie designed and built the Maria Pia Bridge in Porto, Portugal. Original analyses included dead load and three positions of static live loads. The dynamic effects of a train crossing the bridge were not considered. This paper will discuss the original calculations and present a dynamic analysis of a train crossing...

The goal of this paper is to demonstrate the significance of the Bayonne Bridge and to identify it as a work of structural art, because its designer, Othmar Ammann (1879-1965), focused on efficiency, economy, and elegance. To understand Ammann's ideas and his great arch bridge, we will: (1) briefly describe his educational background; (2) explore h...

In dense stellar clusters, binary-single and binary-binary encounters can ultimately lead to collisions involving two or more stars. A comprehensive survey of multi-star collisions would need to explore an enormous amount of parameter space, but here we focus on a number of representative cases involving low-mass main-sequence stars. Using both Smo...