An earthquake resistant pier system for Accelerated Bridge Construction

2021 ◽  
Author(s):  
Jared Cantrell ◽  
Mustafa Mashal ◽  
Arya Ebrahimpour
Keyword(s):  
Seismic Performance ◽  
Large Scale ◽  
Experimental Testing ◽  
The United States ◽  
Accelerated Bridge Construction ◽  
Bridge Construction ◽  
Rapid Construction ◽  
And Performance ◽  
Precast Elements ◽  
Concrete Filled Steel Tubes

<p>Accelerated Bridge Construction (ABC) has been gaining popularity in the United States. ABC offers rapid construction, less traffic disruption, improved quality and on-site safety, better durability, and less environmental impacts. Despite these advantages, application of ABC in seismic regions is still a challenge. In this research, a new precast pier system is proposed to emulate the traditional cast- in-place seismic design (e.g. formation of plastic hinges during earthquakes). The precast elements are connected using telescoping concrete-filled steel tubes in a grouted application. Large-scale experimental testing is carried out to investigate the seismic performance of the proposed pier system and to compare it against the traditional cast-in-place construction. Experimental results showed better ductility, strength and performance of the precast piers compared to cast-in-place benchmarks. Distributed plasticity models are developed to capture the seismic performance of the proposed precast pier system. The Idaho Transportation Department is planning to implement the research in this paper in an actual bridge in Idaho.</p>

Recent Developments on Seismic Resistant Technologies for Accelerated Bridge Construction

2019 ◽  
Author(s):  
Mustafa Mashal ◽  
Alessando Palermo
Keyword(s):  
United States ◽  
New Zealand ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Large Scale ◽  
The United States ◽  
Accelerated Bridge Construction ◽  
Bridge Construction ◽  
Recent Developments ◽  
Seismic Regions

<p>The paper provides an overview of the technologies and connections proposed and tested for accelerated bridge construction (ABC) in seismic regions from New Zealand and the United States in the last seven years. These solutions can be divided in terms of emulative and non‐emulative cast‐in‐place connections. Emulative cast‐in‐place connections aim to achieve a similar seismic performance to that of conventional cast‐in‐place construction during an earthquake. A variety of emulative connections have been tested in New Zealand and in the United States, with some being implemented in actual bridges. These connections include grouted ducts, member socket, pocket, splice‐sleeve, and other connections. Similarly, various non‐emulative connection were tested using large‐scale specimens. These include dissipative controlled rocking, hybrid sliding‐rocking, shape‐memory alloys, and pre‐tensioned rocking. From these, only the dissipative controlled rocking and shape‐memory alloys, have been recently implemented in construction of actual bridges in seismic regions in New Zealand and in the United States, respectively. The paper discusses the aspects associated with emulative and non‐emulative connections.</p>

scholarly journals DUPLICITY IN REGULATION AND PERFORMANCE OF THE FINANCIAL SECTOR IN KENYA

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Dr.Agnes Ogada
Keyword(s):  
Large Scale ◽  
Developing Economies ◽  
Financial Sector ◽  
The United States ◽  
Empirical Literature ◽  
Unique Contribution ◽  
Regulatory Structure ◽  
The Public ◽  
And Performance ◽  
The Uk

Purpose: The objective of the study was to investigate the duplicity in regulation and its effect on performance of the financial sector in Kenya. The specific objectives were; to review and identify regulation duplication/competition in existing regulatory framework for the financial sector in Kenya; to describe how regulatory effectiveness has been measured in empirical literature; to assess whether the current regulatory structure has affected the performance of the financial sector in Kenya and lastly to suggest potential ways of enhancing regulatory effectiveness in Kenya. Methodology: The paper used a desk study review methodology where relevant empirical literature was reviewed to identify main themes and to extract knowledge gaps. Findings: The study found out that financial sector in Kenya and other developing economies have reported losses on a large scale due to under regulation and regulator duplicity. Some of these have become insolvent, or have had to be taken over or rescued by their governments. A single market regulator clearly has its own advantages over multiple regulators. But it is more suitable for well-developed and mature markets which are smaller in size, like the UK. The study also found out that Kenya’s economy and political arena are not mature enough to handle a single financial market regulator. In this light it can be asserted that even mature economies such as the United States still have multiple regulators. Unique contribution to theory, practice and policy: Adherence to principles of open government, including transparency and participation in the regulatory process to ensure that regulation serves the public interest and is informed by the legitimate needs of those interested in and affected by regulation. Governments should ensure that regulations are comprehensible and clear and that parties can easily understand their rights and obligations. Organizations should create personalized technology systems that create a demand adaptation of ICT at every level of the organizational operations

Bombing Flies

2018 ◽  
pp. 223-246
Author(s):  
Clapperton Chakanetsa Mavhunga
Keyword(s):  
United States ◽  
South Africa ◽  
Organochlorine Pesticides ◽  
Large Scale ◽  
The United States ◽  
Ease Of Use ◽  
Technical Aspects ◽  
Aerial Spraying ◽  
And Performance ◽  
Ground Spraying

This chapter explores the use of aircraft to spray organochlorine pesticides (OCPs). It begins by tracing the origins of the practice in KwaZulu, South Africa, where ndege were adopted for pesticide spraying because of their ease of use, capacity for large-scale coverage, very few personnel required, and capability to reach mpukane habitats otherwise inaccessible by ground spraying. The second section examines the technical aspects of aerial spraying as an example of the extension of methods designed in the United States for agricultural or military purposes to deal with zvipukanana and with conditions for which they were not originally designed. In the final sections, the deployment and performance of first fixed-wing aircraft and then helicopters are closely examined.

scholarly journals Study of Bridge Demolition DOT Survey and Available Standard Specifications

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Nazanin Rezaei ◽  
David Garber
Keyword(s):  
Research Effort ◽  
National Level ◽  
The United States ◽  
Point Of View ◽  
Accelerated Bridge Construction ◽  
Limited Information ◽  
Bridge Design ◽  
Bridge Construction ◽  
Aashto Lrfd ◽  
Departments Of Transportation

There are many damaged bridges in the United States which are either structurally deficient or functionally obsolete and require replacement or rehabilitation, many using accelerated bridge construction (ABC) techniques. Before a bridge is replaced or rehabilitated, the old structure or component needs to first be demolished. Although the AASHTO LRFD Bridge Design Specification presents minimum bridge design requirements, there is limited information about bridge demolition available for designers and contractors in this field. More study is required to determine best practices in demolition administration and avoid further unintentional events. This study presents the results from a survey prepared and disseminated through a research effort under the Accelerated Bridge Construction University Transportation Center (ABC-UTC). This survey was sent out to all State Departments of Transportation (DOTs). The results of the survey reveal the need for additional guidance in bridge demolition administrations at a national level. According to the results of this study, contractors are the most important part of bridge demolition projects from injuries, fatalities, and responsibility point of view.

scholarly journals Seismic performance analysis and assessment of a precast bridge computational model

DYNA ◽  
2020 ◽  
Vol 87 (212) ◽  
pp. 80-89
Author(s):  
José Benjumea ◽  
Mehdi Saiidi ◽  
Ahmad Itani
Keyword(s):  
Performance Analysis ◽  
Computational Model ◽  
Seismic Performance ◽  
Earthquake Engineering ◽  
Large Scale ◽  
Three Dimensional ◽  
Shake Table ◽  
Bridge Model ◽  
Precast Elements ◽  
The University

A large-scale, two-span bridge model constructed by assembling precast elements was tested under a series of bi-axial ground motionssimulated on a shake table at the Earthquake Engineering Laboratory at the University of Nevada, Reno. The response of the bridge wasestimated before the tests using a three-dimensional computational model developed in OpenSees software. After the tests, key measuredseismic responses were compared to those predicted by the computational model to assess the modeling assumptions. Relatively largeerrors for the displacements, base shears, and hysteretic response of the bridge were observed. The influence of the earthquake loading,materials, connectivity of the precast elements, and boundary conditions in the computational model on the errors are discussed in thispaper. Future modeling directions are proposed to reduce these errors.

Fluidized Bed Biological Wastewater Treatment: Effects of Scale-Up on System Performance

1990 ◽  
Vol 22 (1-2) ◽  
pp. 419-430 ◽  
Author(s):  
P. M. Sutton ◽  
P. N. Mishra
Keyword(s):  
Fluidized Bed ◽  
Pilot Plant ◽  
Large Scale ◽  
Scale Up ◽  
The United States ◽  
Full Scale ◽  
Fluidized Bed Reactors ◽  
Automotive Manufacturing ◽  
And Performance ◽  
Performance Results

The operation of a number of small and large scale biological fluidized bed pilot plants over the past ten years has resulted in the derivation of process and component information for design of commercial facilities. The General Motors (GM) Corporation represents the single, largest industrial user of the technology in the United States. Ten fluidized bed reactors are located at GM automotive manufacturing facilities. Nine of the reactors are designed to treat wastewaters originating from metalworking operations pretreated for removal of petroleum oils. The other reactor is designed for treatment of sanitary waste-water. In 1984 and 1985, GM completed extensive pilot plant studies and on the basis of the results selected the aerobic fluidized bed (AFB) process configuration for full scale implementation at various plant sites. The fluidized bed reactors located at the sites range in reactor volume from approximately 60 to 730 m3. The pilot plant results which formed the basis for process design of the full scale reactors involved operation of 77 l fluidized bed reactors. Operating information and performance results were derived from evaluation of full scale GM fluidized bed reactors located at the New Departure Hyatt (NDH) plant in Sandusky, Ohio and the Oldsmobile engine plant in Lansing, Michigan. The full scale results were compared to the pilot plant results with the objective of understanding the effects of scale-up on system operation and performance. A comparable level of reactor attached volatile solids (VS) was measured in the pilot and full scale reactors. Biomass net yield coefficients were higher in the full scale reactors, likely due to differences in the composition of the wastewater fed to the full scale versus the pilot scale units. Oxygen utilization coefficients were comparable. The full scale performance results compared favorably with results from the pilot plant studies on the basis of the relationship between effluent quality and reactor solids retention time (SRT).

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