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Full-Text Articles in Engineering

Load Distribution Of Adjacent Prestressed Concrete Box Beam Bridges, Luis F. Urrego, Ryan T. Whelchel, Robert J. Frosch, Christopher S. Williams Aug 2018

Load Distribution Of Adjacent Prestressed Concrete Box Beam Bridges, Luis F. Urrego, Ryan T. Whelchel, Robert J. Frosch, Christopher S. Williams

The Summer Undergraduate Research Fellowship (SURF) Symposium

One of the most common bridge types is the adjacent prestressed concrete box beam bridge because the system is economical and simple to build; over 43,000 are currently in service within the US. However, they are highly susceptible to strand corrosion and concrete deterioration which can result in early loss of load capacity. Therefore, an experimental program sponsored by the Indiana Department of Transportation (INDOT) was initiated to determine the behavior of deteriorated beams and develop recommendations for load rating and design of this bridge type. Displacement sensors were installed on a bridge in service to measure its deformation under …


Performance Of Mud Mortar Walls Under Seismic Loading, Christian L. Berneking Vi, Santiago Pujol, Prateek Pratap Shah, Lucas Laughery Aug 2017

Performance Of Mud Mortar Walls Under Seismic Loading, Christian L. Berneking Vi, Santiago Pujol, Prateek Pratap Shah, Lucas Laughery

The Summer Undergraduate Research Fellowship (SURF) Symposium

The inherently brittle nature of unreinforced masonry structures results in poor performance during earthquakes, presenting major hazards to communities. Many of these structures found in Nepal were severely damaged or destroyed during two earthquakes in 2015. The purpose of this project is to test the effect on seismic response of several modifications to stone and mud mortar structures. These structures are common in many areas of Nepal. Two T-shaped stone and mud mortar masonry walls are constructed. The first wall has no modifications and represents current building practices. The second wall uses steel wire mesh as external reinforcement. Each wall …


The Effect Of Reinforcing Bar Bend Radius On The Strength And Behavior Of Knee Joints, Xitong Zhou, Christopher S. Williams, Hwa Ching Wang Aug 2017

The Effect Of Reinforcing Bar Bend Radius On The Strength And Behavior Of Knee Joints, Xitong Zhou, Christopher S. Williams, Hwa Ching Wang

The Summer Undergraduate Research Fellowship (SURF) Symposium

The strut-and-tie method (STM) is used by structural engineers to design discontinuity regions of reinforced concrete structures. Using STM, the stress distribution in a concrete member is expressed as a set of struts, ties, and nodes in a strut-and-tie model. These components are then proportioned and evaluated to develop an appropriate design. One type of node that appears in knee joints (i.e., frame corners) subjected to closing moments is referred to as a curved-bar node. Although curved-bar nodes represent a unique concentration of stresses in a structure, little research focused on curved-bar node design has been conducted. In response to …


Buckling Of Cylindrical Shells Under Wind Loading, Tianlong Sun, Eyas Azzuni, Sukru Guzey Aug 2017

Buckling Of Cylindrical Shells Under Wind Loading, Tianlong Sun, Eyas Azzuni, Sukru Guzey

The Summer Undergraduate Research Fellowship (SURF) Symposium

Cylindrical shells such as aboveground steel storage tanks are widely used to store gases, chemicals and fuels. Stiffener rings are introduced to prevent cylindrical shells from buckling due to wind loads. The current top wind stiffener design rules used in the USA for such cylindrical storage tanks are specified in API 650. However, the design methodology of top stiffener rings is overly conservative. Therefore, relaxation of the design rules for the top stiffener is investigated in this study. The API 650 mandated top stiffener size was reduced to the same size as the mandated intermediate stiffener ring in this study. …


Hazard Assessment Of Meteoroid Impact For The Design Of Lunar Habitats, Herta Paola Montoya, Shirley Dyke, Julio A. Ramirez, Antonio Bobet, H. Jay Melosh, Daniel Gomez Aug 2017

Hazard Assessment Of Meteoroid Impact For The Design Of Lunar Habitats, Herta Paola Montoya, Shirley Dyke, Julio A. Ramirez, Antonio Bobet, H. Jay Melosh, Daniel Gomez

The Summer Undergraduate Research Fellowship (SURF) Symposium

The design of self-sustaining lunar habitats is a challenge primarily due to the Moon’s lack of atmospheric protection and hazardous environment. To assure safe habitats that will lead to further lunar and space exploration, it is necessary to assess the different hazards faced on the Moon such as meteoroid impacts, extreme temperatures, and radiation. In particular, meteoroids pose a risk to lunar structures due to their high frequency of occurrence and hypervelocity impact. Continuous meteoroid impacts can harm structural elements and vital equipment compromising the well-being of lunar inhabitants. This study is focused on the hazard conceptualization and quantification of …


Post-Earthquake Fire Assessment Of Steel Buildings, Yi Li, Rachel Chicchi, Amit H. Varma Aug 2017

Post-Earthquake Fire Assessment Of Steel Buildings, Yi Li, Rachel Chicchi, Amit H. Varma

The Summer Undergraduate Research Fellowship (SURF) Symposium

Resilience of structural systems after hazardous events is a crucial concern of building design. An abundance of research has focused on hazards such as seismic and fire separately. This project conducted a multi-hazard study on steel buildings considering both seismic and fire damage. A literature review of the behavior of steel-framed buildings due to fires after earthquakes, known as post-earthquake fires (PEF), is offered. The new PEF methodology, delivered in this study, starts with creating a three dimensional (3D) model of the examined steel building using the finite element method software, ABAQUS. Next, varying intensities of seismic and fire hazards …


Strength Of Reinforced Concrete Beams With High-Strength Steel, Brian C. Rogers, Aishwarya Puranam, Santiago Pujol Aug 2016

Strength Of Reinforced Concrete Beams With High-Strength Steel, Brian C. Rogers, Aishwarya Puranam, Santiago Pujol

The Summer Undergraduate Research Fellowship (SURF) Symposium

Structures are commonly made of reinforced concrete, which is a composite material made of concrete and steel reinforcement. Using high-strength steel, with yield stress larger than 100 ksi, could help reduce the quantity of steel required in structural members, thus reducing costs and improving constructability. The hypothesis being tested is that smaller quantities of high-strength steel reinforcement (HSSR) can be used in place of conventional steel in reinforced concrete beams while maintaining similar strength and deformation at failure. Two reinforced concrete beams with two different types of longitudinal steel reinforcement were constructed. The beams were 18 in. wide, 30 in. …


High Strength Steel In The Reinforced Concrete Structures: Serviceability, Alan Kanybek, Aishwarya Puranam, Santiago Pujol Aug 2016

High Strength Steel In The Reinforced Concrete Structures: Serviceability, Alan Kanybek, Aishwarya Puranam, Santiago Pujol

The Summer Undergraduate Research Fellowship (SURF) Symposium

The use of high-strength steel (yield stress larger than 100 ksi) in reinforced concrete structures can provide an effective alternative to using conventional steel (yield stress up to 80 ksi). The goal of this study is to investigate if slabs with reduced quantities of high-strength steel reinforcement meet the serviceability criteria. Instantaneous and long-term deflections in slab specimens with conventional steel and reduced amounts of high-strength steel (as compared with conventional steel) were studied. Two sets of two reinforced concrete slabs, each 14 ft. long, 30 in. wide, were built. The depth, quantity, and type of longitudinal reinforcement were varied …


Straining Definitions, William Pollalis, Santiago Pujol Aug 2015

Straining Definitions, William Pollalis, Santiago Pujol

The Summer Undergraduate Research Fellowship (SURF) Symposium

The concept of strain is ubiquitous in engineering textbooks. It is defined early in engineering education as change in length divided by initial length, and is used to quantify deformations due to things like stresses and temperature changes. The concept itself is quite straightforward and represents homogenous materials well, but homogenous materials are rarely present in engineering design. Composite materials such reinforced concrete cannot be simply defined, as their properties are heavily influenced by their non-uniformity. For example, there are large deformations around tensile cracks in reinforced concrete, where the reinforcement withstands all the tensile stress, and little deformation in …


Role Of Soil Parameters On Loading Of Buried Structures, Xiao Zhang, Mark D. Bowman, Rafael R. Armendariz Briones Aug 2015

Role Of Soil Parameters On Loading Of Buried Structures, Xiao Zhang, Mark D. Bowman, Rafael R. Armendariz Briones

The Summer Undergraduate Research Fellowship (SURF) Symposium

Load rating is the process to evaluate and explore the structural capacity of bridges as much as possible within safety range. As a balance between economy and safety, proper load ratings save money and keep public safe. Knowing the contribution and interaction of each different soil parameter on the loading can significantly reduce the amount of work when load rating those structures. However, for buried structures without plans, such contribution or interaction is never known. This parametric study explores how much each soil parameter of three types of soils can affect the loading of buried structures without plans. An existing …


Seismic Vulnerability Assessment Of Low-Rise Reinforced Concrete Buildings In Kathmandu, Nepal, Prateek Pratap Shah, Santiago Pujol Aug 2015

Seismic Vulnerability Assessment Of Low-Rise Reinforced Concrete Buildings In Kathmandu, Nepal, Prateek Pratap Shah, Santiago Pujol

The Summer Undergraduate Research Fellowship (SURF) Symposium

In seismically active cities like Kathmandu, there often exists a need to assess the seismic vulnerability of a large number of poorly designed buildings within a short period of time. Traditional analysis techniques do not work because they require building data that are either inaccurate or unavailable. One alternative to traditional analysis techniques is to use simple correlations like the Priority Index. This index uses basic building information such as floor area, column area, and wall area to estimate the seismic vulnerability of a building. Following the 2015 Nepal earthquake, 146 low-rise reinforced concrete buildings were surveyed in Kathmandu, Nepal. …


Finite Element Analysis Of Bolted Connections Under Fire, Ke Liu, Qiaqia Zhu, Amit H. Varma Aug 2014

Finite Element Analysis Of Bolted Connections Under Fire, Ke Liu, Qiaqia Zhu, Amit H. Varma

The Summer Undergraduate Research Fellowship (SURF) Symposium

Over the course of human history, fire disasters are one of the major catastrophes that causes loss of lives and properties. In order to ensure building safety against fire, civil engineers seek to understand the behavior of structures at high temperatures. Moreover, they need to study the behavior of bolted connections, given the important role it plays in steel structures. Sarraj (2007) proposed a plate-bearing computational model used to describe this behavior; however, it has never been experimentally verified. Prior to this specific project, a series of single-bolted connection tests at 400°C and 600°C were conducted in the Bowen Laboratory …


Compression Testing And Failure Modes Of Steel-Concrete Composite (Sc) Structures For Nuclear Containment, Patrick Michael Wanamaker, Amit H. Varma Oct 2013

Compression Testing And Failure Modes Of Steel-Concrete Composite (Sc) Structures For Nuclear Containment, Patrick Michael Wanamaker, Amit H. Varma

The Summer Undergraduate Research Fellowship (SURF) Symposium

Although being able to provide much cleaner power than burning coal and other fossil fuels, nuclear power plants are still a tough sell to the general public due to their history of being spontaneously dangerous. The containment structures surrounding these nuclear plants, however, can play a huge role in reducing the risks associated with them. Relatively new designs for these containment assemblies, known as SC (steel-concrete composite) structures, aim to increase the strength and durability of the containment facilities while keeping costs down. By varying the spacing between shear studs, the ratio of concrete to steel, and the ratio of …


Real-Time-Hybrid-Simulation Of Multi-Degree-Of-Freedom Systems With Multiple Time Steps, Lanxi Liu, Arun Prakash Oct 2013

Real-Time-Hybrid-Simulation Of Multi-Degree-Of-Freedom Systems With Multiple Time Steps, Lanxi Liu, Arun Prakash

The Summer Undergraduate Research Fellowship (SURF) Symposium

Computational simulation and physical experiments are both widely used in testing the response of a structure under earthquake loadings, but physical experiments can be expensive for large problems and numerical may result in the loss of important structural behavior caused by a large amount of assumptions. Real-time hybrid simulation (RTHS) is a combination of these two approaches, which uses both a numerical and physical substructures that interact in real time to simulate structural behavior. The numerical and physical substructures are connected using a transfer system that enforces compatibility between them. The physical substructure needs to be run at a very …


Recursive Multi-Time-Step Coupling Of Multiple Subdomains, Yukun An, Payton Lindsay, Xiaowo Wang, Arun Prakash Oct 2013

Recursive Multi-Time-Step Coupling Of Multiple Subdomains, Yukun An, Payton Lindsay, Xiaowo Wang, Arun Prakash

The Summer Undergraduate Research Fellowship (SURF) Symposium

The need for efficient computation methods for modeling of large-scale structures has become critically important over the past few years. Efficient means of analysis often involve coupling in space through domain decomposition and multi scale methods in time. The multi-time-step coupling method is a coupling method in time which allows for efficient analysis of large-scale problems for structural dynamics where a large structural model is decomposed into smaller subdomains that are solved independently and then coupled back together to obtain the global solution. For coupling of more than two subdomains that are solved at different timesteps, we employ recursive methods. …