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Full-Text Articles in Engineering

Pressure Loss Coefficients For Large Mitered Elbows With Diameters Ranging From 36-Inches To 144-Inches, Hayden J. Coombs May 2019

Pressure Loss Coefficients For Large Mitered Elbows With Diameters Ranging From 36-Inches To 144-Inches, Hayden J. Coombs

All Graduate Theses and Dissertations

When designing a pipeline system, it is important to understand the pressure losses that will occur within the system. One common source of pressure loss is from elbow pipe fittings. There is extensive research available for pressure loss coefficients of elbow pipe fittings, but the research is derived from elbows with relatively smaller pipe diameters. The purpose of this research is to investigate pressure losses associated with larger diameter mitered elbows (36-inches to 144-inches). The dimensions for all mitered elbows considered in this research follow ANSI/AWWA C208-17 recommendations (AWWA 2017).

Due to the large size of the mitered elbows ...


Measuring Nitrogen Transformation In Wastewater Impacted Streams Using In-Situ Benthic Chambers, Makenzi Beltran May 2019

Measuring Nitrogen Transformation In Wastewater Impacted Streams Using In-Situ Benthic Chambers, Makenzi Beltran

All Graduate Theses and Dissertations

Acrylic chambers and metal frames were installed at the sediment-water interface of streams impacted by the effluent from wastewater reclamation facilities in order to determine nitrogen rates for nitrification, denitrification, assimilation, ANAMMOX, and DNRA. Each chamber was dosed with an isotopic form of nitrate (15NO3 - ), and both isotopic (15N) and non-isotopic (14N) samples were collected. The project locations included East Canyon Creek near the East Canyon Wastewater Reclamation Facility in Park City, Utah and Box Elder Creek near the Brigham City Wastewater Treatment Plant in Brigham City, Utah. Separate chamber measurements were conducted upstream and downstream ...


Synopsis Of Engineers Without Borders (Ewb) Trip, Guatemala January 5 To January 12, 2019, Willis Weight Apr 2019

Synopsis Of Engineers Without Borders (Ewb) Trip, Guatemala January 5 To January 12, 2019, Willis Weight

Engineers Without Borders

The Carroll Guatemala Engineers Without Borders (EWB) team assembled at a variety of locations from around the western USA before traveling together as a group into Guatemala City from a flight from Los Angeles. The flight from Los Angeles on Saturday morning departed about 11:00 AM local time. Two of us departed about 6:00 am from the Missoula airport (Willis Weight and Kennedy Bahm) and the following students: Ian Kirby, Josiah Groux, Amelia Schuver, Ericka Seehafer, Mary Van Dyke (health and safety officer), and Amber Pickering (project leader) came in from Portland, Seattle, and SLC). Professional mentor Ryan ...


The Influence Of Asphalt Ageing On Induction Healing Effect On Porous Asphalt Concrete, Shi Xu, Xueyan Liu, Amir Tabakovic, Erik Schlangen Feb 2019

The Influence Of Asphalt Ageing On Induction Healing Effect On Porous Asphalt Concrete, Shi Xu, Xueyan Liu, Amir Tabakovic, Erik Schlangen

Articles

Induction healing is a proven technology which is able to improve the self‐healing capacity of asphalt concrete. Healing is achieved via electromagnetic current produced by passing induction machine, where steel asphalt constituents heat up which in turn soften the bitumen in the asphalt layer, allowing it to flow and close cracks, repairing the damage. This paper reports on the study which investigated the influence of ageing on the healing capacity of Porous Asphalt (PA) concrete. Porous Asphalt concrete mix was prepared first, then subjected to an accelerated (laboratory) ageing process using a ventilated oven. In order to further evaluate ...


Motion-Based Design Approach For A Novel Variable Friction Cladding Connection Used In Wind Hazard Mitigation, Yongqiang Gong, Liang Cao, Simon Laflamme, James Ricles, Spencer Quiel, Douglas Taylor Feb 2019

Motion-Based Design Approach For A Novel Variable Friction Cladding Connection Used In Wind Hazard Mitigation, Yongqiang Gong, Liang Cao, Simon Laflamme, James Ricles, Spencer Quiel, Douglas Taylor

Civil, Construction and Environmental Engineering Publications

Cladding systems typically serve architectural purposes and protect occupants against the external environment. It is possible to leverage these systems to enhance structural resiliency. A common application is the use of blast resistant panels for enhanced protection against man-made hazards, whereas energy is dissipated through sacrificial elements. However, because these protection systems are passive, their mitigation capabilities are bandwidth limited, therefore targeting single types of hazards. The authors have recently proposed a novel variable friction cladding connection (VFCC), which enables the leveraging of cladding inertia for mitigating blast, wind, and seismic hazards. The variation in the friction force is generated ...


Download Bmp Trains 2020 Newest Version, Martin Wanielista Feb 2019

Download Bmp Trains 2020 Newest Version, Martin Wanielista

BMP Trains

BMP Trains 2020 is an improvement from all previous versions – most notably because of the departure from the Microsoft Excel platform to being programmed and compiled using the C++ programming language. The entire user interface and much of the internal function has been completely overhauled, while still preserving the essential goal of quantifying pre- and post-development average annual nutrient loadings (Nitrogen and Phosphorus) and determining the average annual effectiveness of a wide variety of Best Management Practices (BMPs) for the nutrients’ removal. The research by Dr. Harvey Harper, Dr. Marty Wanielista, Dr. Mike Hardin, Eric Livingston, and others in computing ...


A Primer On The Safe Systems Approach, Christopher M. Monsere Feb 2019

A Primer On The Safe Systems Approach, Christopher M. Monsere

Christopher M. Monsere

A presentation given at the Bellevue, WA Vision Zero Summit Feb 2019


User Manual - Bmp Trains 2020 Version 1.2.5, Martin Wanielista Feb 2019

User Manual - Bmp Trains 2020 Version 1.2.5, Martin Wanielista

BMP Trains

A user's manual to accompany the computer program called BMP Trains 2020. The user's manual provides example problems useful to understanding the program. The user's manual is updated when there is a need to respond to user inputs. The program is used to assess the average annual effectiveness of nutrient removal from combinations of stormwater BMPs.


The Effect Of Fine Material Amount On Optimum Water Content Of Roller Compacted Concrete, Kubilay Akçaözoğlu, Bedrettin Menemencioğlu Feb 2019

The Effect Of Fine Material Amount On Optimum Water Content Of Roller Compacted Concrete, Kubilay Akçaözoğlu, Bedrettin Menemencioğlu

International Journal of Business and Technology

In this study the effect of fine material amount on the optimum water content of roller compacted concrete (RCC) was investigated. The fine aggregate was replaced with calcite which maximum particle size was 63 μ, in amount of 0%, 2%, 4%, 6%, 10% and 14% by weight of total aggregate. Six different mixtures were prepared in the study. The optimum water contents of the mixtures were determined by using modified proctor test. Optimum water content, maximum dry unit weight and maximum fresh unit weight of produced specimens were measured. Optimum water content of specimens decreased depending on increasing fine aggregate ...


The Effect Of Particles Pm10 And Pm2.5 In Dust Emission Of Urban Infrastructure From Thermal Power Plant Technology Kosovo, Afrim Syla Feb 2019

The Effect Of Particles Pm10 And Pm2.5 In Dust Emission Of Urban Infrastructure From Thermal Power Plant Technology Kosovo, Afrim Syla

International Journal of Business and Technology

Airborne particulate matter with aerodynamic diameters less than 10 microns (referred to as PM10) is one of the six criteria pollutants used by the U.S. Environmental Protection Agency as indicator of air quality. During the last decade, the health effects of urban aerosols have become a major concern for the society.

The main environmental problems in Kosovo include all issues related to water supply and sanitation system, air quality, solid waste management and urban infrastructure. The major problem remains high pollutions, energy losses and low collection efficiency. The awareness of environmental issues among the general public is poor. Air ...


Using Of Proper Pavement Material For The Intersections With Slow-Moving Traffic, Bekim Selimi Feb 2019

Using Of Proper Pavement Material For The Intersections With Slow-Moving Traffic, Bekim Selimi

International Journal of Business and Technology

Use of proper pavement material for some of intersections need special attention by road designers. At Camp Bondsteel-Kosovo on 2002 were built four road intersections using the concrete as pavement material. Heavy and slow-moving trucks that are turning or accelerating exposed these intersections to some of the highest stress level. After some years this intresections start deteriorating on their surface due to friction. The concrete pavements did not survive this period of usage and after eight years were removed and replaced with asphalt pavements. After more than seven years, the asphalt has shown minor distress but is still in good ...


The Effect Of Elevated Temperature On The Lightweight Concrete Containing Waste Pet Aggregate, Semiha Akçaözoğlu Feb 2019

The Effect Of Elevated Temperature On The Lightweight Concrete Containing Waste Pet Aggregate, Semiha Akçaözoğlu

International Journal of Business and Technology

In this study, the effect of waste PET as lightweight aggregate (WPLA) replacement with conventional aggregate on the some physical and mechanical properties and residual compressive strength of concrete was investigated. For this purpose, five different mixtures were prepared (the reference mixture and four WPLA mixtures including 30%, 40%, 50% and 60% waste PET aggregate by volume). The fresh and dry unit weights, compressive strengths, flexural-tensile strengths, water absorption and porosity ratios of the mixtures were measured. In addition the specimens exposed to elevated temperatures at 150, 300 and 450 °C and the residual compressive strengths were measured. Test results ...


Negative Impacts (Sbs) In Residential Buildings Case Studies From Kosovo, Muhamet Ahmeti, Mimoza Sylejmani Feb 2019

Negative Impacts (Sbs) In Residential Buildings Case Studies From Kosovo, Muhamet Ahmeti, Mimoza Sylejmani

International Journal of Business and Technology

This paper presents the negative impacts on residential buildings in Kosovo, - as well as the main factors of the occurrence of sick building syndrome (SBS) in residential buildings in the case of Kosovo. It also examines the impact of different materials on this phenomenon and how many constructions in Kosovo are protected from this phenomenon.

For the assessment of the impact of materials on health and the environment, it is necessary to consider all the phases. Starting from the phase of construction, selection of materials, application from the beginning of the use of the building, including all the materials processing ...


Reducing The Porosity And Sealing Cracks By Using Crystalline Admixture In Conventional Concrete, Visar Krelani, Liberato Ferrara Feb 2019

Reducing The Porosity And Sealing Cracks By Using Crystalline Admixture In Conventional Concrete, Visar Krelani, Liberato Ferrara

International Journal of Business and Technology

There is a continuous increase of quality on civil engineering materials in developed countries and parallel increase of need for new constructions in developing countries. Professional community should propose solutions for the durability that can resist in different severe environments. The most important factor that can affect concrete durability is represented by the pore distribution. Transport properties can take place through the porous network inside the cementitious composites and the aggregates interface, permitting the ingress of aggressive agents damaging concrete function intrinsically as a material and the wellfunctioning of the entire structure. The use of a crystalline admixture during the ...


Optimal Design Of Grillage Structures With Steel Crossed Beams Using Genetic Algorithms, Ersilio Tushaj, Niko Lako, Fatjon Saliu Feb 2019

Optimal Design Of Grillage Structures With Steel Crossed Beams Using Genetic Algorithms, Ersilio Tushaj, Niko Lako, Fatjon Saliu

International Journal of Business and Technology

The optimal problem in the structural design is an important issue in the engineering design. Various authors have analyzed the optimization of steel structures using algorithmic approaches. These techniques are generally grouped in deterministic or meta-heuristic techniques. From the introduction of structural optimization in the 1960’ up to now, various methods have been proposed. A genetic algorithm, is built and applied in this study using MatLab soft R2017a to a crossed beams system. The structural analysis is done with the direct stiffness method with constraints verification based on EuroCode 3:2005 criteria. Results are reported in the study.


Seismic Actions Induced By Cladding Panels On Precast Concrete Frame Structures, Bruno Dal Lago, Francesco Foti, Luca Martinelli Feb 2019

Seismic Actions Induced By Cladding Panels On Precast Concrete Frame Structures, Bruno Dal Lago, Francesco Foti, Luca Martinelli

International Journal of Business and Technology

The strong earthquakes occurred in Southern Europe in the last decade pointed out a poor seismic performance of the connection system of the cladding of precast industrial structures. The cladding of these buildings usually consists of sandwich concrete panels of remarkable mass, connected to the frame structure with mechanical devices. The estimation of the out-of-plane seismic action on these connections is a key step for their correct proportioning. However, the formulation currently provided in the Eurocode 8 for the estimation of the seismic action on non-structural elements was calibrated with different objectives. Furthermore, given there is no in-plane structure-panel interaction ...


Hyperspectral Image Analysis For Mechanical And Chemical Properties Of Concrete And Steel Surfaces, Liang Fan, Paul Manley, Huaishuai Shang, Abdullah Alhaj, Hongyan Ma, Genda Chen Feb 2019

Hyperspectral Image Analysis For Mechanical And Chemical Properties Of Concrete And Steel Surfaces, Liang Fan, Paul Manley, Huaishuai Shang, Abdullah Alhaj, Hongyan Ma, Genda Chen

Genda Chen

According to the 2017 ASCE Report Card, 39% and 15% of 614,387 bridges in the U.S. are more than 50 years and 40 to 49 years, respectively. The number of deficient bridges is increasing. One of the most common causes of reinforced concrete deterioration is corrosion of steel reinforcing bars. Currently, most bridges are visually inspected every two years using boom/snooper trucks to get access to various areas to be inspected. The subjective visual inspection often leads to inconsistent results that are less useful in bridge management. Hyperspectral camera, installed on an unmanned aerial vehicle, can potentially ...


Uav-Enabled Measurement On Magnetic Field Of Smart Rocks For Bridge Scour Monitoring, Haibin Zhang, Zhaochao Li, Genda Chen Feb 2019

Uav-Enabled Measurement On Magnetic Field Of Smart Rocks For Bridge Scour Monitoring, Haibin Zhang, Zhaochao Li, Genda Chen

Genda Chen

Scour and other hydraulic induced failures accounted for 58% of over 1,500 bridge collapses in the U.S. Bridge scour is the engineering term for the erosion of soil surrounding a bridge foundation as a result of water current. Monitoring with fixed and/or portable instrumentations is one of the most effective measures in mitigating scour hazards. However, fixed instrumentation with sensors installed prior to flood events cannot detect scour other than the area instrumented. It is susceptible to the harsh environment during a flood event. Portable instrumentation is difficult to deploy during a severe flood event due to ...


Integrated Fiber Optic Sensors For Strain, Temperature And Corrosion-Induced Mass Loss Measurement, Chuanrui Guo, Liang Fan, Genda Chen Feb 2019

Integrated Fiber Optic Sensors For Strain, Temperature And Corrosion-Induced Mass Loss Measurement, Chuanrui Guo, Liang Fan, Genda Chen

Genda Chen

In this study, a fiber optic sensing system based on long period fiber gratings (LPFG) in LP06 and LP07 modes is designed, fabricated and tested for simultaneous measurements of strain, temperature and corrosion-induced mass loss. It consists of three steel tubes and several Fe-C coated LPFG sensors for long- and short-term corrosion monitoring, respectively, when deployed in proximity and parallel to a steel member. Graphene/silver nanowire (Gr/AgNW) composite was coated on the LPFG surface for efficient Fe-C electroplating due to its high optical transparency and conductivity. The sensor was subjected to both tensile strain and temperature, and submerged ...


The Effects Of Silica On The Properties Of Vitreous Enamels, Signo Tadeu Dos Reis, Mike Koenigstein, Liang Fan, Genda Chen, Luka Pavic, Andrea Mogus-Milankovic Feb 2019

The Effects Of Silica On The Properties Of Vitreous Enamels, Signo Tadeu Dos Reis, Mike Koenigstein, Liang Fan, Genda Chen, Luka Pavic, Andrea Mogus-Milankovic

Genda Chen

Ground coat enamels for low carbon steel that contain silica as a mill addition have been developed to study the changes of their properties. Acid-resistant commercial enamel where silica addition was varied from 0 to 10.0 wt % was used for this investigation. The effects of the addition on the corrosion resistance, thermal properties, electrical properties, and mechanical adherence of the enamel to low carbon steel were studied. The corrosion resistance of the steel enameled coupons was tested using a salt spray (fog) apparatus for time periods reaching 168 h at room temperature. It was found that, although the density ...


Feasibility Of Distributed Fiber Optic Sensor For Corrosion Monitoring Of Steel Bars In Reinforced Concrete, Liang Fan, Yi Bao, Genda Chen Feb 2019

Feasibility Of Distributed Fiber Optic Sensor For Corrosion Monitoring Of Steel Bars In Reinforced Concrete, Liang Fan, Yi Bao, Genda Chen

Genda Chen

This study investigates the feasibility of distributed fiber optic sensor for corrosion monitoring of steel bars embedded in concrete. Two sensor installation methods are compared: (1) attaching the sensor along the bar and (2) winding the sensor on the bar. For the second method, optical fibers were winded spirally on steel bars with different spacings: 0 mm, 2 mm, 5 mm, and 10 mm. Steel bar pull-out testing was conducted to evaluate the effect of presence of distributed sensor on the bond strength of steel—concrete interface. Electrochemical testing was carried out to assess the influence of the installation methods ...


Characterization, Source Apportionment And Health Analysis Of Air Pollutants In India, Hao Guo Feb 2019

Characterization, Source Apportionment And Health Analysis Of Air Pollutants In India, Hao Guo

LSU Doctoral Dissertations

In recent years, severe pollution events occurred frequently in India, which are of significant concern of the public. However, limited studies have been conducted to understand the formation, sources and health effects of high pollution levels and the information for design of effective control strategies is urgently needed. First, criteria air pollutants data at 10 sites for 2017 in Delhi were analyzed to understand the current pollution status. The results show that annual fine particulate matter (PM2.5) concentrations exceeded the National Ambient Air Quality Standards (NAAQS), India of 60 µg/m3 at all sites. Source-oriented versions of ...


Critical Analysis Of Case Law: Are Partnering Charters Binding?, Milagros Pinto Nunez, Douglas D. Gransberg Feb 2019

Critical Analysis Of Case Law: Are Partnering Charters Binding?, Milagros Pinto Nunez, Douglas D. Gransberg

Civil, Construction and Environmental Engineering Publications

Construction project partnering in the United States has been used successfully for nearly 30 years in reducing disputes. Most partnered projects are characterized by the joint development of a nonbinding partnering charter between the owner and the contractor, which encapsulates the project’s goals and lays out the desired process for resolving issues at the lowest level. This paper explores the outcomes when partnered projects fail and the parties involved must turn to the courts to settle their disputes. The paper evaluates the case law for 16 partnered projects through content analysis and cross-case comparison. The paper explores the question ...


Discussion: Effect Of Bentonite Slurry Pressure On Interface Friction Of Pipe Jacking, Ciaran Reilly, Trevor Orr Feb 2019

Discussion: Effect Of Bentonite Slurry Pressure On Interface Friction Of Pipe Jacking, Ciaran Reilly, Trevor Orr

Articles

Pipe jacking is a technique used to construct tunnels by pushing prefabricated pipes through the ground from an entrance shaft to an exit shaft. This technique is referred as microtunneling in U.S. terminology, therefore, in the rest of the text, pipejacking and microtunneling will be used as having the same meaning. Pipe jacking is a more economical alternative to segmental lined tunnels. However, the main limitation of pipe jacking is the jacking distance, which is directly dependent on the friction between the pipe and the soil. Therefore, reducing the friction between the pipe and soil is a critical issue ...


Data Evidencing Slow Anaerobic Digestion In Emergency Treatment And Disposal Of Infectious Animal Carcasses, Jacek A. Koziel, Heekwon Ahn, Thomas D. Glanville, Timothy S. Frana, J. (Hans) Van Leeuwen, Lam T. Nguyen Feb 2019

Data Evidencing Slow Anaerobic Digestion In Emergency Treatment And Disposal Of Infectious Animal Carcasses, Jacek A. Koziel, Heekwon Ahn, Thomas D. Glanville, Timothy S. Frana, J. (Hans) Van Leeuwen, Lam T. Nguyen

Agricultural and Biosystems Engineering Publications

Burial of infectious and potentially infectious livestock and poultry animals is the most common response to an emergency situation. The data set summarizes 22-week-long experiment that simulates the environment found within conventional burial trenches for emergency disposal of animal carcasses, worldwide, sometimes with a topical application of quicklime as it is required in the Republic of Korea. This data set shows the rarely presented evidence of the extremely slow decay of animal carcasses. Besides visual evidence of no visible breakdown of carcass material, i.e., carcass (or carcass quarters and coarse cuts) still resembled the initial material at the end ...


Sea Level Rise And Land Subsidence In Coastal Louisiana: Forecasting, Mapping And Identification Of At-Risk Transportation Infrastructure, Sanjay Tewari, Francis Manning, Wesley Palmer Jan 2019

Sea Level Rise And Land Subsidence In Coastal Louisiana: Forecasting, Mapping And Identification Of At-Risk Transportation Infrastructure, Sanjay Tewari, Francis Manning, Wesley Palmer

Dr. Sanjay Tewari

The coast of Louisiana is under threat because of sea level rise and land subsidence. Sea water is encroaching deeper inland and as a result Louisiana is losing land at an alarming rate. The combined effect of sea level rise and land subsidence is variable spatially. This paper focuses on this combined effect in identifying the transportation infrastructure that is at risk of getting affected by the seawater inundation of the land.

This paper attempts to account for land elevation data monitored continuously at various locations along the coast of Louisiana and combining it with local sea level rise to ...


Optimization Of The Calcium Alginate Capsules For Self-Healing Asphalt, Shi Xu, Amir Tabakovic, Xueyan Liu, Damian Palin, Erik Schlangen Jan 2019

Optimization Of The Calcium Alginate Capsules For Self-Healing Asphalt, Shi Xu, Amir Tabakovic, Xueyan Liu, Damian Palin, Erik Schlangen

Articles

Featured Application: This self-healing technology for asphalt pavements has the potential to greatly disrupt asphalt production methods (which have been stable over the past 100 years).This paper presents a development process of ‘calcium-alginate microcapsules encapsulating an asphalt bitumen rejuvenator’. The encapsulated rejuvenator is released when required (on demand) which rejuvenates the aged binder. Once crack is initiated and starts propagating it encounters a microcapsule, energy at tip of the crack opens the microcapsule, releasing the rejuvenator (healing agent). The rejuvenator will infuse into the aged binder soften it, allowing to flow, two broken edges to get into a contact ...


Performance Test On Styrene-Butadiene-Styrene (Sbs) Modified Asphalt Based On The Different Evaluation Methods, Chen Zhang, Hainian Wang, Zhanping You, Junfeng Gao, Muhammad Irfan Jan 2019

Performance Test On Styrene-Butadiene-Styrene (Sbs) Modified Asphalt Based On The Different Evaluation Methods, Chen Zhang, Hainian Wang, Zhanping You, Junfeng Gao, Muhammad Irfan

Department of Civil and Environmental Engineering Publications

To uniform the evaluation indicators of Styrene-Butadiene-Styrene (SBS) modified asphalt, the SK70# and SK90# matrix asphalt were modified by different SBS modifier dosage in this study. The test methods in China and Superpave were used to test the performance of each SBS-modified asphalt respectively, from which the appropriate evaluation index of SBS-modified asphalt was determined. The results showed that the addition of SBS modifier improved the high temperature performance and lowered the temperature sensitivity of asphalt binder, while it increased the viscosity of asphalt binder in high temperatures. Due to the variability that appeared in the results of the penetration ...


Low-Density Static Granular Media Filter Bed Turbidity Removal Model, Matthew Louque Jan 2019

Low-Density Static Granular Media Filter Bed Turbidity Removal Model, Matthew Louque

LSU Master's Theses

The scattering of light within a fluid, referred to as its turbidity, was investigated against the presence of suspended solids. A linear regression analysis was conduced against turbidity and the total count, combined surface area, and combined volume of the suspended particles for various surface water sources (lakes, rivers, indoor aquaculture systems). It was found that the total combined surface area of suspended particles had the best linear correlation to turbidity, with an adjusted R2 of 81.79%. This correlation was integrated with a current theoretical model for predicting solids removal across a granular bed to yield an Integrated ...


Signal Mast Arm Fatigue Failure Investigation, Genda Chen, Michael G. Barker, Lokeswarappa R. Dharani, Christopher W. Ramsay Jan 2019

Signal Mast Arm Fatigue Failure Investigation, Genda Chen, Michael G. Barker, Lokeswarappa R. Dharani, Christopher W. Ramsay

Lokeswarappa Dharani

The Missouri Department of Transportation (MoDOT) has discovered and documented failures in several cantilever mast arms in the recent years. The failures were primarily by fatigue at the weld of the arm to the base plate attached to the mast. With over 6000 mast arms in service in Missouri, the failures raised concerns with the existing mast arm inventory and future mast arm design. This report presents findings from an effort to determine the cause of unexpected cracking in Missouri mast arms. Three causes of premature failure were investigated: the stress ranges experienced at the weld detail were higher than ...