scholarly journals Pavement Optimisation With Aggregate Base Or Asphalt Layers Stabilised With Hexagonal Geogrids

2021 ◽  
Vol 1202 (1) ◽  
pp. 012024
Author(s):  
Michał Gołos ◽  
Piotr Mazurowski
Keyword(s):  
Fatigue Life ◽  
Natural Resources ◽  
Carbon Footprint ◽  
Design Method ◽  
Environmental Benefits ◽  
Beneficial Effects ◽  
Traffic Capacity ◽  
Pavement Structures ◽  
Aggregate Base ◽  
Asphalt Overlays

Abstract The use of hexagonal geogrids in pavement structures results in the increase of the life of designed structure. This offers the possibility to reduce the thickness of layers without reduction of pavement life, or to increase the traffic capacity of a pavement without the need to increase its thickness. This way of using geogrids in pavements design was introduced to the pavement industry by one producer of hexagonal geogrids as a Pavement Optimisation (PO) concept. It can be transformed into both economic and environmental benefits, and obviously results in savings of natural resources and reduction of carbon footprint of a project. PO with geogrids can be used both in the newly designed pavement structures, and in the asphalt overlays of the existing old pavements. Asphalt overlays enhancement with a geogrid either increases the fatigue life of overlays or allows the reduction of overlays thickness to achieve the same pavement life. In new pavements, stabilisation of aggregate base with geogrids increases the stiffness of aggregate, which increases the performance of a whole pavement. This paper presents several tests results, which confirm beneficial effects of using hexagonal geogrids in asphalt overlays and aggregate base layers, from laboratory to full scale accelerated pavement tests. Also, modifications of Mechanistic-Empirical pavement design method, which allow to implement the geogrid benefits into the design process, are discussed. Finally, case studies of pavements – newly designed and reconstructed – optimised with hexagonal geogrids are presented.

scholarly journals Translating a Global Emission-Reduction Framework for Subnational Climate Action: A Case Study from the State of Georgia

2021 ◽  
Vol 67 (2) ◽  
pp. 205-227
Author(s):  
Marilyn A. Brown ◽  
Blair Beasley ◽  
Fikret Atalay ◽  
Kim M. Cobb ◽  
Puneet Dwiveldi ◽  
...  
Keyword(s):  
Carbon Footprint ◽  
Global Solutions ◽  
High Impact ◽  
Environmental Benefits ◽  
Future Research ◽  
Carbon Footprints ◽  
Carbon Reduction ◽  
Global Emission ◽  
Greenhouse Gas Reduction ◽  
Climate Action

AbstractSubnational entities are recognizing the need to systematically examine options for reducing their carbon footprints. However, few robust and comprehensive analyses are available that lay out how US states and regions can most effectively contribute. This paper describes an approach developed for Georgia—a state in the southeastern United States called “Drawdown Georgia”, our research involves (1) understanding Georgia’s baseline carbon footprint and trends, (2) identifying the universe of Georgia-specific carbon-reduction solutions that could be impactful by 2030, (3) estimating the greenhouse gas reduction potential of these high-impact 2030 solutions for Georgia, and (4) estimating associated costs and benefits while also considering how the solutions might impact societal priorities, such as economic development opportunities, public health, environmental benefits, and equity. We began by examining the global solutions identified by Project Drawdown. The resulting 20 high-impact 2030 solutions provide a strategy for reducing Georgia’s carbon footprint in the next decade using market-ready technologies and practices and including negative emission solutions. This paper describes our systematic and replicable process and ends with a discussion of its strengths, weaknesses, and planned future research.

Modeling and Optimization of Ultra High Pressure Vessel With Self-Protective Flat Steel Ribbons Wound and Tooth-Locked Quick-Actuating End Closure

2008 ◽  
Author(s):  
Xin Ma ◽  
Zhongpei Ning ◽  
Honggang Chen ◽  
Jinyang Zheng
Keyword(s):  
High Pressure ◽  
Fatigue Life ◽  
Pressure Vessel ◽  
Design Method ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Peak Stress ◽  
High Pressure Vessel ◽  
Ultra High Pressure ◽  
Flat Steel

Ultra-High Pressure Vessel (UHPV) with self-protective Flat Steel Ribbons (FSR) wound and Tooth-Locked Quick-Actuating (TLQA) end closure is a new type of vessel developed in recent years. When the structural parameters of its TLQA and Buttress Thread (BT) end closure are determined using the ordinary engineering design method, Design by Analysis (DBA) shows that the requirement on fatigue life of this unique UHPV could hardly be satisfied. To solve the above problem, an integrated FE modeling method has been proposed in this paper. To investigate the fatigue life of TLQA and BT end closures of a full-scale unique UHPV, a three-dimensional (3-D) Finite Element (FE) solid model and a two-dimensional (2-D) FE axisymmetric model are built in FE software ANSYS, respectively., Nonlinear FE analysis and orthogonal testing are both conducted to obtain the optimum structure strength, in which the peak stress in the TLQA or BT end closure of the unique UHPV is taken as an optimal target. The important parameters, such as root structure of teeth, contact pressure between the pre-stressed collar and the cylinder end, the knuckle radius, the buttress thread profile and the local structure of the cylinder, are optimized. As a result, both the stress distribution at the root of teeth and the axial load carried by each thread are improved. Therefore, the load-carrying capacity of the end closure has been reinforced and the fatigue life of unique UHPV has been extended.

scholarly journals Effects of climate change on environmental sustainability

2021 ◽  
Vol 250 ◽  
pp. 01005
Author(s):  
Manuela Tvaronavičienė
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Natural Resources ◽  
Carbon Footprint ◽  
Environmental Sustainability ◽  
Industrial Pollution ◽  
Climatic Conditions ◽  
Adaptation Strategies ◽  
Viable Solution ◽  
The World

Adaptation strategies to the climate change include measures that can be taken to take account of the new climatic conditions. This paper aims at assessing the effects of climate change on environmental sustainability. This sustainability constitutes a major problem in many countries and regions around the world that experience industrial pollution, degradation of land as well as natural disasters caused by the global warming. The paper shows that adaptation strategies are often parallel strategies that can be integrated simultaneously with the management of natural resources. They can make resources more efficient and resilient to climate change. The paper shows that reducing the carbon footprint by more than 50 percent by 2030 and eliminating it by 2050 might be a viable solution how to tackle the climate change and support the environmental sustainability.

Full-Scale Evaluation of Relatively Thin Airfield Pavements

2020 ◽  
Vol 2674 (10) ◽  
pp. 658-669
Author(s):  
W. Jeremy Robinson ◽  
Jeb S. Tingle ◽  
Carlos R. Gonzalez
Keyword(s):  
Asphalt Concrete ◽  
Test Section ◽  
Concrete Surface ◽  
Full Scale ◽  
Test Items ◽  
Pavement Structures ◽  
Base Course ◽  
And Performance ◽  
Rutting Behavior ◽  
Aggregate Base

A full-scale airfield pavement test section was constructed and trafficked by the U.S. Army Engineer Research and Development Center (ERDC) to evaluate the performance of relatively thin airfield pavement structures. The test section consisted of four test items that included three asphalt pavement thicknesses and two different aggregate base courses. The test items were subjected to simulated aircraft traffic to evaluate their response and performance to realistic aircraft loads. Rutting behavior, instrumentation response, and falling weight deflectometer response were monitored at selected traffic intervals. It was found that the performance of the airfield pavement sections were most sensitive to aggregate base course properties, where a 50% reduction in base course strength resulted in a 99% reduction in allowable passes. The data suggested that when sufficient asphalt thickness is not provided, the failure mechanism shifted from subgrade failure to base course failure, particularly at higher subgrade CBR values. In addition, the number of aircraft passes sustained was less than that predicted by current Department of Defense (DOD) methods that include assumptions of a high-quality aggregate base and a minimum asphalt concrete thickness. The results of this study were used to extend existing DOD pavement design and evaluation techniques to include the evaluation of airfield pavement sections that do not meet the current criteria for aggregate base quality and minimum asphalt concrete surface thickness. These performance data were used to develop a new base failure design curve using existing stress-based design criteria.

The Iterative Method for Reliability Estimation of Fatigue Life

2012 ◽  
Vol 249-250 ◽  
pp. 628-631
Author(s):  
Xin Li Bai ◽  
Peng Xu ◽  
Jiang Yan Li
Keyword(s):  
Fatigue Life ◽  
Design Method ◽  
Estimation Method ◽  
Engineering Application ◽  
Reliability Estimation ◽  
Fatigue Reliability ◽  
Reliability Design ◽  
Fatigue Design ◽  
Machine Parts ◽  
Stress Cycles

The expression of reliability estimation method for fatigue life of machine parts was derived, and two kinds of stress cycles (reversed cycle and un-symmetric reversed cycle) were considered. An iteration method is presented and the corresponding computer program named STRENGTH-2 is developed for estimating reliable life of machine parts. The engineering application results show that the calculated results are close to experimental results. The proposed method can be convenient to carry out the fatigue reliability design for machine parts under the action of uni-axial and multi-axial loadings, and promote the popularization and application of existing anti-fatigue design method. It has the high value of engineering application.

Research on Fatigue Life of the Casting Crane’s Girder

2011 ◽  
Vol 295-297 ◽  
pp. 598-602
Author(s):  
Zhi Cheng Huang
Keyword(s):  
Fatigue Life ◽  
Fracture Mechanics ◽  
Design Method ◽  
Three Dimensional ◽  
Data Access ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Safe Operation

Taken a certain type of casting crane’s girder as research object, established its three-dimensional model by using Pro/ENGINEER software, and then import it into the ANSYS program for analysis with ANSYS data access module (DDA), integrating the analysis results and the theory of fracture mechanics, the thesis comprehensively analyzed the fatigue life of the casting crane’s girder with damnification-limit design method. It provided some theory basis and reference for casting crane’s safe operation and fatigue lift design.

Reliability Estimation of Fatigue Life for Machine Parts under Uniaxial Constant Amplitude Load

2012 ◽  
Vol 249-250 ◽  
pp. 632-635
Author(s):  
Yu He Li ◽  
Xin Li Bai ◽  
Ying Fang Zhang
Keyword(s):  
Fatigue Life ◽  
Design Method ◽  
Engineering Application ◽  
Reliability Estimation ◽  
Estimation Methods ◽  
Fatigue Reliability ◽  
Constant Amplitude ◽  
Reliability Design ◽  
Fatigue Design ◽  
Machine Parts

Two methods acquiring p-S-N curve for machine parts are given, namely directly searching out the p-S-N curve of the material from material database and using the idealized p-S-N curve. Reliability estimation methods of fatigue life of machine parts are derived under uniaxial constant amplitude load. Two kinds of circumstances (fixed stress and probabilistic stress) and two kinds of stress cycles (reversed cycle and unsymmetric reversed cycle) are considered. An iteration method is presented and the corresponding computer program is developed for estimating reliable life of machine parts. The engineering application results show that the calculated results are closer to experimental results. The suggested method can be convenient to fatigue reliability design of machine parts. It has good stimulative effect on popularization and application of existing anti-fatigue design method for machine parts, and high value of engineering application.

scholarly journals KAWASAN WISATA AIR TERJUN DAIT DI KABUPATEN LANDAK

2021 ◽  
Vol 9 (2) ◽  
pp. 525
Author(s):  
Windi Guswirno Hedi ◽  
Syaiful Muazir ◽  
Valentinus Pebriano
Keyword(s):  
Natural Resources ◽  
Community Participation ◽  
Design Method ◽  
Function Analysis ◽  
Local Communities ◽  
Ecological Functions ◽  
West Kalimantan ◽  
Analysis Process ◽  
Service Areas ◽  
Tourism Potential

Landak Regency has many natural resources that have the potential to be used as natural tourism objects. One of them is Dait Waterfall which has 7 floors and is located in an unspoiled forest area. The area is often visited by tourists from various regions of West Kalimantan. However, there are several problems related to supporting facilities and infrastructure that are not up to standard for tourism activities, so that the tourism potential is not maximized. For this reason, it is necessary to design a "Dait Waterfall Tourism Area in Landak Regency" which is in accordance with tourism standards and local environmental needs, with the concept of ecotourism that uses a sustainable environmental approach and empowerment of local communities. The arrangement is done by designing which starts from the function analysis process, which includes the main functions and supporting functions. The main functions include recreational aspects and supporting functions consisting of commercial functions, ecological functions and community participation functions. The design method consists of the introduction, definition, preparation, analysis, synthesis, evaluation and re-evaluation stages. The design process is applied in the construction of the main tourism facilities and infrastructure such as outbound areas, camping areas, selfie areas, and others. In addition, supporting facilities and infrastructure such as management areas, commercial areas, service areas, utility aspects, and others. With this design, it is hoped that the Dait Waterfall Tourism Area will attract more tourists from a wider variety of areas.

scholarly journals Durability of concrete pavement strengthened with asphalt layer with FRP fibres

2018 ◽  
Vol 64 (3) ◽  
pp. 81-97
Author(s):  
P. Tutka ◽  
R. Nagórski ◽  
P. Radziszewski ◽  
M. Sarnowski ◽  
M. Złotowska
Keyword(s):  
Fatigue Life ◽  
Concrete Slab ◽  
Asphalt Mixture ◽  
Concrete Pavement ◽  
Cement Concrete ◽  
Asphalt Overlay ◽  
Road Pavement ◽  
Traffic Loads ◽  
Pavement Structures ◽  
The Impact

SummaryPavements made of cement concrete, used for road constructions, are damaged during use. This applies to both the pavements of rural and forest roads with very low traffic loads, as well as road pavements with high traffic loads. One of the most effective ways of repairing damaged concrete cement pavements is through placing an asphalt overlay on a concrete slab. In order to increase the fatigue life of the asphalt overlay, asphalt mixtures are modified with fibres. One technological solution is to use FRP (Fiber Reinforced Polymer), an innovative material with improved properties. The aim of this paper is to assess the impact of asphalt overlays modified with a new type of fibres to strengthen the durability of weakened cement concrete pavement structures. On the basis of the conducted analyses, it was shown that the use of an asphalt layer reinforcement increases fatigue life, for both 15 cm thick prefabricated slabs and a typical road pavement for average traffic made of 25 cm doweled and anchored concrete slabs. There was a significant increase in the fatigue life of the concrete pavement structure as a result of modifying the overlaid asphalt mixture with FRP fibres.

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