scholarly journals Synthesis of Repair Materials and Methods for Reinforced Concrete and Prestressed Bridge Girders

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4079
Author(s):  
Azin Ghaffary ◽  
Mohamed A. Moustafa
Keyword(s):  
Reinforced Concrete ◽  
The United States ◽  
Economic Feasibility ◽  
Bridge Girders ◽  
Repair Materials ◽  
Bridge Structures ◽  
Repair Procedure ◽  
Prestressed Bridge Girders ◽  
Bridge Girder ◽  
Local Opposition

Bridge structures nationwide across the United States are aging and in need of repair or, in some cases, full replacement. Repair decisions are common among bridge owners because of the economic feasibility when compared to the higher cost of full replacement of damaged or deteriorated bridge components such as girders. Using a proper repair approach, as a long-term or just a short-term solution, can lead to benefits that could not be achieved otherwise such as considerable savings in both time and cost. Additionally, an appropriate repair approach can help avoid adverse environmental impacts, interruptions to service, overburdening of nearby infrastructure, and local opposition to construction. The main objective of this paper is to provide a synthesis of the repair methods and materials for reinforced concrete bridge girders proposed in research studies, i.e., state-of-the-art as well as state-of-the-practice established methods. Different steps in the general repair procedure are explained first. Next, a detailed description of three common bridge girder deficiencies, i.e., shear, flexural, and fire damage, is provided. For each damage type, the main causes and common solutions found in the literature are presented. The authors then provide specific recommendations to each repair procedure. This is intended to enable researchers, engineers, and decision makers to compare the available repair methods more conveniently to find the optimal repair approach for specific projects based on economic and environmental requirements as well as structural and construction conditions.

Design of Various Shear Connectors for Repair of Corroded Steel Girders with Ultra-High Performance Concrete

2019 ◽  
Vol 2673 (2) ◽  
pp. 521-530 ◽  
Author(s):  
Dominic Kruszewski ◽  
Arash E. Zaghi
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
The United States ◽  
Extensive Study ◽  
Bottom Flange ◽  
Load Path ◽  
Ultra High Performance Concrete ◽  
Shear Connectors ◽  
Repair Procedure ◽  
Bridge Girder

Corrosion accounts for approximately 20% of the structurally deficient bridges in the United States, causing a massive backlog of rehabilitation projects. The current repair procedure for corroded bridge girders is expensive, slow to implement, and necessitates complete closure of the bridge. Through an extensive study supported by the Connecticut Department of Transportation, a novel repair method has been developed to rapidly restore the strength of corroded bridge girder ends with minimal traffic interruption. First, shear connectors in the form of headed studs are welded on the uncorroded web plate above the bearing. Next, formwork is placed and ultra-high-performance concrete (UHPC) is cast down to the bottom flange. This creates an alternate load path around the section loss. Based on the experimental results, it may be concluded that the implementation of the repair reduces the strains on the web plate and strengthens the bridge girder, allowing it to surpass its original capacity. However, the success of the repair centers around the performance of the shear connectors. In addition to headed studs, threaded bars and UHPC dowels in perforated web were evaluated experimentally as alternative shear-transfer mechanisms. This paper presents the repair design objectives and considerations for a realistic girder end utilizing different shear connectors to demonstrate the flexibility and versatility of the repair. The details of the designs are illustrated to facilitate the transition of the research findings to practice.

Feasibility Analysis of Using UHPC in Prestressed Bridge Girders

2011 ◽  
Author(s):  
Christopher W. Taylor ◽  
Kristin F. Montoya ◽  
David V. Jáuregui ◽  
Craig M. Newtson ◽  
Brad D. Weldon
Keyword(s):  
Feasibility Analysis ◽  
Bridge Girders ◽  
Prestressed Bridge Girders

Implementing the performance-based seismic design for new reinforced concrete structures: Comparison among ASCE/SEI 41, TBI, and LATBSDC

2021 ◽  
pp. 875529302098196
Author(s):  
Siamak Sattar ◽  
Anne Hulsey ◽  
Garrett Hagen ◽  
Farzad Naeim ◽  
Steven McCabe
Keyword(s):  
Reinforced Concrete ◽  
Los Angeles ◽  
Seismic Design ◽  
Common Ground ◽  
Seismic Analysis ◽  
Tall Buildings ◽  
The United States ◽  
Analysis And Design ◽  
Performance Based Seismic Design ◽  
New Buildings

Performance-based seismic design (PBSD) has been recognized as a framework for designing new buildings in the United States in recent years. Various guidelines and standards have been developed to codify and document the implementation of PBSD, including “ Seismic Evaluation and Retrofit of Existing Buildings” (ASCE 41-17), the Tall Buildings Initiative’s Guidelines for Performance-Based Seismic Design of Tall Buildings (TBI Guidelines), and the Los Angeles Tall Buildings Structural Design Council’s An Alternative Procedure for Seismic Analysis and Design of Tall Buildings Located in the Los Angeles Region (LATBSDC Procedure). The main goal of these documents is to regularize the implementation of PBSD for practicing engineers. These documents were developed independently with experts from varying backgrounds and organizations and consequently have differences in several degrees from basic intent to the details of the implementation. As the main objective of PBSD is to ensure a specified building performance, these documents would be expected to provide similar recommendations for achieving a given performance objective for new buildings. This article provides a detailed comparison among each document’s implementation of PBSD for reinforced concrete buildings, with the goal of highlighting the differences among these documents and identifying provisions in which the designed building may achieve varied performance depending on the chosen standard/guideline. This comparison can help committees developing these documents to be aware of their differences, investigate the sources of their divergence, and bring these documents closer to common ground in future cycles.

scholarly journals Economic feasibility of cooling dry cows across the United States

2016 ◽  
Vol 99 (12) ◽  
pp. 9931-9941 ◽  
Author(s):  
F.C. Ferreira ◽  
R.S. Gennari ◽  
G.E. Dahl ◽  
A. De Vries
Keyword(s):  
United States ◽  
The United States ◽  
Economic Feasibility

Application of Fly Ash-Based Geopolymer for Structural Member and Repair Materials

2014 ◽  
Vol 92 ◽  
pp. 74-83 ◽  
Author(s):  
Wanchai Yodsudjai
Keyword(s):  
Reinforced Concrete ◽  
Fly Ash ◽  
Concrete Beam ◽  
Setting Time ◽  
Reinforced Concrete Beam ◽  
Structural Member ◽  
Steel Reinforcement ◽  
Flexural Behavior ◽  
Fundamental Properties ◽  
Repair Materials

The applications of using fly ash-based geopolymer as a structural member and a repair materials in reinforced concrete structure was conducted. The optimum mix proportion of fly ash-based geopolymer concrete using for structural beam and fly ash-based geopolymer mortar using for repair material were developed. The flexural behavior of fly ash-based geopolymer reinforced concrete and the durability aspect namely the corrosion of steel reinforcement were investigated using the electrical acceleration. For the repair purpose, the fundamental properties; that is, compressive strength, flexural strength, bonding strength between fly ash-based geopolymer mortar and mortar substrate, setting time and chloride penetration were investigated. Also, the durability of conventional reinforced concrete beam repaired by the fly ash-based geopolymer mortar comparing with the comercial repair mortar was investigated. The behavior of the fly ash-based geopolymer reinforced concrete beam was similar to that of the conventional reinforced concrete beam; however, the corrosion of the steel reinforcement of the fly ash-based geopolymer reinforced concrete beam was higher than that of the conventional reinforced concrete beam. The fundamental properties of the fly ash-based geopolymer mortar were not different from that of the commercial repair materials; however, the durability of the reinforced concrete beam repaired by the fly ash-based geopolymer mortars performed a little lower than that of repaired with the commercial repair motar and also the control reinforced concrete with no repair. As a result, even there will be still a need of improvement there was a good tendency for using the fly ash-based geopolymer as the structural member and the repair materials.

scholarly journals OBJECTS OF TRANSPORT INFRASTRUCTURE: EXPERIENCE OF SCIENTIFIC SUPPORT IN CONSTRUCTION WITHIN THE “QUALITY” CONCEPT IMPLEMENTATION

2019 ◽  
Vol 16 (5) ◽  
pp. 618-634
Author(s):  
I. S. Pulyaev ◽  
S. M. Pulyaev
Keyword(s):  
Reinforced Concrete ◽  
Building Materials ◽  
Concrete Structures ◽  
Economic Feasibility ◽  
Transport Infrastructure ◽  
Building Structures ◽  
Construction Technology ◽  
Scientific Support ◽  
Free Construction ◽  
Modern Building

Introduction. The paper deals with the issues related to the implementation of the “quality” concept in the construction of reinforced concrete transport facilities linked with the scientific support during design and construction. Nowadays this problem particularly relevant in the context of the modern construction solutions, combined with the need to obtain the required properties of concrete structures and ensure the economic feasibility of construction. The aim of the research is to generalize and systematize the main methods and techniques of concrete works, which minimize the defects and cracks while the construction of transport infrastructure.Materials and methods. On the example of different technologies used in the Russian construction over last 10 years, the authors demonstrated the developed methods of obtaining high quality concrete products taking into account tested and proved modern building materials.Results. The results of the research formed the basis of the projects, technological regulations for the production, specifications and standards of organizations, guidelines. Moreover, the results also allowed implementing the concept of “quality” in transport construction based on obtaining defect-free reinforced concrete structures with specified properties, taking into account the use of modern building materials.Discussion and conclusions. The research allows carrying out construction of various massiveness and extent. The obtained results form the basis of construction technology of other industrial and civil construction objects with reinforced concrete application. The paper is interesting and useful for specialists in providing defect-free construction of reinforced concrete building structures, for engineering and technical staff. The authors dedicate the research to the memory of Professor and Doctor of Technical Sciences, A.R. Solovyanchik (1938-2019).

scholarly journals Private space flights: legal regulation in the United States

2020 ◽  
pp. 382-388
Author(s):  
Оleksandr Zadorozhny
Keyword(s):  
United States ◽  
Space Flight ◽  
The United States ◽  
Legal Regulation ◽  
Economic Feasibility ◽  
Gradual Transition ◽  
Significant Shift ◽  
Private Space ◽  
Space Flights ◽  
The Usa

The emergence of demand for space travel, the emergence of commercial enterprises and travel agencies in the space industry,the development of vehicles designed exclusively for transporting tourists into space – all this suggests that space may soon turn froma scientific object into a common destination. Therefore, today the legal regulation of private space flights is a promising issue, giventhat there is no such legislation in Ukraine. We turn to the analysis of the legislation of the United States of America to assess whatarray of regulations we will have to master if we want to develop private space flights at home.A private space flight is a space flight or development of space flight technology that is conducted and paid for by an entity otherthan a government agency. Depending on the purpose, private space flights are divided into flights for the purpose of transportation ofcargoes, and flights within the framework of space tourism.The article presents an overview and analysis of the legislation of the USA regulating private space flights, in particular, flightsfor the purpose of transportation of cargoes, and flights in the framework of space tourism. The author highlights a chronological formationof the commercialization of space, which clearly shows the gradual transition of the United States from a complete reluctanceto allow private space flights to the recognition of the indisputable economic feasibility of such activities. A significant shift in this areahas taken place since 2015, when five directives on space policy, the National Space Strategy and orders on the exploration, extractionand use of space resources were adopted.The author analyzes the main sources of space law in the United States. It was found that mostly, the legislation does not keepup with innovations in the commercialization of space, thus, there is a situation when first comes a relationship (flight of a tourist orcargo into space), and then – the legislative regulation of such relations.

Development of fiber reinforced concrete repair materials

2006 ◽  
Vol 33 (2) ◽  
pp. 126-133 ◽  
Author(s):  
N Banthia ◽  
R Gupta ◽  
S Mindess
Keyword(s):  
British Columbia ◽  
Reinforced Concrete ◽  
Cellulose Fiber ◽  
Fiber Reinforced Concrete ◽  
Test Method ◽  
Fiber Reinforced ◽  
Parking Garage ◽  
Shrinkage Cracking ◽  
University Of British Columbia ◽  
Repair Materials

Early age shrinkage cracking remains a critical concern for cement-based repairs and overlays. Fibers mitigate such cracking, but no standardized technique of assessing the performance of a given fiber exists. Recently, a novel technique of making such an assessment was developed at The University of British Columbia (UBC). In this test method, currently being balloted through the ASTM, an overlay of fiber reinforced concrete (FRC) material to be tested is cast directly on a fully matured sub-base with protuberances, and the entire assembly is subjected to controlled drying. Cracking in the overlay is then monitored and characterized. The technique was recently employed to develop "crack-free" overlay materials for two repair sites. One was a parking garage in Downtown Vancouver, British Columbia, and the other was the plaza deck at The UBC Aquatic Center. For the parking garage, a carbon fiber reinforced concrete and for the plaza deck, a cellulose fiber reinforced concrete were developed. Both overlays were instrumented with strain sensors and data were monitored over the Internet.Key words: fiber reinforced concrete, shrinkage cracking, strain monitoring, carbon fibers, cellulose fibers.

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