Engineering Commons^™

Reliability Of Sfrp-Strengthened Rc Bridge Columns Subjected To Blast Loads, Ahmad Alsendi, Christopher D. Eamon

Civil and Environmental Engineering Faculty Research Publications

The reliability of reinforced concrete bridge columns strengthened with externally bonded, steel-fiber reinforced polymer fabric subjected to blast loads was investigated. Columns were modeled with a nonlinear finite element approach that considers material damage, fracture, and separation. Different concrete strengths, longitudinal reinforcement ratios, and gravity and blast load levels were considered, while uncertainties in material strength and stiffness parameters, as well as load characteristics, were incorporated in the probabilistic analysis. It was found that the use of SFRP can allow significant increases in blast load while maintaining the same level of column reliability.

Seismic Design Coefficients For Speedcore Or Composite Plate Shear Walls - Concrete Filled (C-Psw/Cf), Shubham Agrawal, Morgan Broberg, Amit H. Varma

Bowen Laboratory Research Reports

This report summarizes the results from FEMA P695 analytical studies conducted to verify the seismic design factors for composite plate shear walls – concrete filled (C-PSW/CF), also referred to as Speedcore. ASCE 7-16 provides the seismic design factors, which include the seismic response modification factor, R, deflection amplification factor, C_d, and overstrength factor, Ω_o, for various approved seismic systems. C-PSW/CFs are assigned a response modification factor of 6.5, a deflection amplification factor of 5.5, and an overstrength factor of 2.5 for C-PSW/CFs. These seismic design factors were selected based on the seismic performance of similar structural …

Quantitative Resistance Assessment Of Sfrp-Strengthened Rc Bridge Columns Subjected To Blast Loads, Ahmad Alsendi, Christopher D. Eamon

Civil and Environmental Engineering Faculty Research Publications

The blast resistance of a typical reinforced concrete bridge pier column design was modeled with a nonlinear finite element approach that considers material damage, fracture, and separation. While varying concrete strength, amount of longitudinal reinforcing steel, and gravity load, the effect of applying an externally bonded steel fiber reinforced polymer (SFRP) wrapping was assessed. The presented approach uniquely quantifies column blast resistance in terms of charge weight. It was found that blast capacity was roughly linearly related to concrete strength and steel reinforcement ratio, the former of which is most influential. It was further found that a single layer of …

Generalized Beam–Spring Model For Predicting Elastic Behavior Of Partially Composite Concrete Sandwich Wall Panels, Salam Al-Rubaye, Taylor Sorensen, Robert J. Thomas, Marc Maguire

Faculty Publications

Partially composite sandwich wall panels (SWP) have been used in the construction industry for at least twenty years. Currently there is limited codified guidance for designers of partially composite concrete SWP, but they are being designed safely and routinely. Design is often guided by the composite connector manufacturers who sell proprietary composite connectors often using a variation of truss-type matrix methods for prediction of elastic behavior of SWPs. The purpose of this paper is to quantify the accuracy of such a model in a uniform manner by developing a generalized version of these matrix models called the beam-spring model (BSM). …

A Novel Concrete-Based Sensor For Detection Of Ice And Water On Roads And Bridges, Habib Tabatabai, Mohammed Aljuboori

Civil and Environmental Engineering Faculty Articles

Hundreds of people are killed or injured annually in the United States in accidents related to ice formation on roadways and bridge decks. In this paper, a novel embedded sensor system is proposed for the detection of black ice as well as wet, dry and frozen pavement conditions on roads, runways, and bridges. The proposed sensor works by detecting changes in electrical resistance between two sets of stainless steel poles embedded in the concrete sensor to assess surface and near-surface conditions. A preliminary decision algorithm is developed that utilizes sensor outputs indicating resistance changes and surface temperature. The sensor consists …

Ductile Corrosion-Free Gfrp-Stainless Steel Reinforced Concrete Elements, Maged A. Youssef, Mohamed E. Meshaly, Ahmed Elansary

Civil and Environmental Engineering Publications

Corrosion of steel rebars is known to cause deterioration of concrete structures that can lead to catastrophic failures. To mitigate this problem, steel rebars can be replaced with Glass Fiber-Reinforced Polymer (GFRP) rebars. However, the lack of ductility of GFRP-reinforced elements has prevented their use in many structural applications, especially in seismic areas. Stainless Steel (SS) rebars are corrosion resistant and have adequate energy absorption and ductility. However, they are much more expensive than steel rebars. This paper proposes the combined use of SS and GFRP rebars to achieve ductile and corrosion-free elements. The first challenge for such a proposal …

Phase I Evaluation Of Selected Concrete Material Models In Ls-Dyna, Bradley J. Winkelbauer

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Numerous roadside safety systems are configured with reinforced concrete materials, such as bridge railings, median barriers, and roadside parapets. These protective barrier systems are intended to safely contain and redirect errant vehicles as well as prevent impacts into hazardous fixed objects or other geometric features. The analysis and design of these structures may involve impact simulation with finite element software, like LS-DYNA, which includes multiple concrete material models. For such investigations, limited guidance is available for selecting preferred concrete material models and determining appropriate values for specific parameters. This Phase I study investigated the viability and performance of existing concrete …

The Performance And Service Life Prediction Of High Performance Concrete In Sulfate And Acidic Environments, Shuo Zhang

FIU Electronic Theses and Dissertations

Concrete substructures are often subjected to environmental deterioration, such as sulfate and acid attack, which leads to severe damage and causes structure degradation or even failure. In order to improve the durability of concrete, the High Performance Concrete (HPC) has become widely used by partially replacing cement with pozzolanic materials. However, HPC degradation mechanisms in sulfate and acidic environments are not completely understood. It is therefore important to evaluate the performance of the HPC in such conditions and predict concrete service life by establishing degradation models.

This study began with a review of available environmental data in the State of …

Mechanical And Transport Properties Of Alkali-Activated Natural Pozzolans As Sustainable Binders, Brittany Radke

Calvert Undergraduate Research Awards

OPC production accounts for 5 to 7% of the global carbon dioxide (CO₂) emissions, contributing to global warming. The desire to reduce CO₂ emissions and produce more durable concrete has given impetus to search for new binders. It is suggested that alkali-activated natural pozzolans have the potential for use as a sustainable replacement for OPC in concrete.

The current study presented herein evaluated fresh, mechanical, and transport properties of alkali-activated natural pozzolan mortars containing various concentrations of sodium hydroxide solutions as an alkaline activator. To this aim, alkali-activated natural pozzolan mortars were made with concentrations of sodium …

Reliability-Based Design Optimization Of Concrete Flexural Members Reinforced With Ductile Frp Bars, Bashar Behnam, Christopher D. Eamon

Civil and Environmental Engineering Faculty Research Publications

In recent years, ductile hybrid FRP (DHFRP) bars have been developed for use as tensile reinforcement. However, initial material costs regain high, and it is difficult to simultaneously meet strength, stiffness, ductility, and reliability demands. In this study, a reliability-based design optimization (RBDO) is conducted to determine minimum cost DHFRP bar configurations while enforcing essential constraints. Applications for bridge decks and building beams are considered, with 2, 3, and 4-material bars. It was found that optimal bar configuration has little variation for the different applications, and that overall optimized bar cost decreased as the number of bar materials increased.

Precast/Prestressed Concrete Truss-Girder For Roof Applications, Peter S. Samir

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

Steel trusses are the most popular system for supporting long span roofs in commercial buildings, such as warehouses and aircraft hangars. There are several advantages of steel trusses, such as lightweight, ease of handling and erection, and geometric flexibility. However, they have some drawbacks, such as high material and maintenance cost, and low fire resistance. In this paper, a precast concrete truss is proposed as an alternative to steel trusses for spans up to 160 ft. without intermediate supports. The proposed design is easy to produce and has lower construction and maintenance costs than steel trusses. The proposed design is …

Historic Bridge Evaluation Using Finite Element Techniques, Helena M. Charron

Masters Theses 1911 - February 2014

The present study examined the application of modern, computer-based analysis methods to two existing historic bridges in Massachusetts. The first bridge featured in this study is the Woronoco Bridge, a reinforced concrete open spandrel arch bridge that was constructed in 1923. It was hoped that a computer-based, parametric study of this bridge would prove it to be deck-stiffened, similar to select bridges of Swiss engineer Robert Maillart. However, the results do not support that there was any intent to reduce bending in the arch as a result of increasing the stiffness of the bridge deck. Instead, the Woronoco Bridge appears …

Enhancing Concrete Barrier Reflectivity With A Focus On Recycled Glass Aggregate Replacement, Regina Shklyan

Masters Theses 1911 - February 2014

Increased accident rates during the nighttime and wet weather conditions on the United States highways necessitate the enhancement of highway concrete barrier visibility. The visibility of these delineators is dependent on their reflectivity. Several methods are proposed that stand to increase the reflectivity of these concrete barriers, such as the use of white cement versus gray cement and the attachment of raised pavement markers to the side of the barriers. The incorporation of recycled glass into the concrete mixture is one of the proposed methods that was put through further laboratory study. The aim of the laboratory testing was to …

Nonlinear Model For Reinforced Concrete Under Cyclic Loading, Aly Said, M. Elmorsi, M. Nehdi

Civil and Environmental Engineering and Construction Faculty Research

Most of the available shear models for reinforced concrete rely on empirical formulations. In this study, a rational shear stress function is used to define the shear stress–strain envelope for reinforced concrete. Cyclic rules are proposed to define the loading, unloading and reloading relationships for reinforced concrete under shear stress reversals. A normal stress function describing the cyclic relationship of concrete under axial stress is also introduced. The proposed functions are verified using experimental data of reinforced concrete panels tested under monotonic and cyclic loading. Subsequently, the normal and shear stress functions along with their cyclic rules are integrated in …