324 research outputs found
The Impact of Hurricane Harvey on Pavement Structures in the South East Texas and South West Louisiana
This study developed a methodology to estimate the damage caused by flooding, such that caused by Hurricane Harvey, on a road or street network. The flooded street or pavement sections are identified using GIS flood maps with street GIS maps used for pavement management systems (PMS) by cities or state authorities. Then the damage caused by flooding directly through the increase moisture in foundation layers or indirectly due to the increase heavy traffic during the relief effort is estimated. An example Excel macro was created to illustrate the estimation process. The methodology estimates the increase in rehabilitation costs since the flooding imposes that many rehabilitation works must be done earlier than anticipated before the flooding. The methodology also estimated the increase in fuel consumption caused by the increased in pavement roughness if the rehabilitation works are done when anticipated before the flooding. The methodology and the Excel macro can also be used to identify the pavement structures with better resilience to the flooding by grouping sections based on the flooding duration (no flooding, single and multiple day flooding) and on design features such as pavement type, functional class, age or time from the most recent resurfacing or reconstruction, subgrade soil type, traffic volume, layer thickness
Urban Runoff Control and Sponge City Construction
The rapid urbanization, sometimes lacking adequate planning and design, has led to worsening city syndrome situations, such as urban flooding, water pollution, heat island effects, and ecologic deterioration. Sponge city construction have become the new paradigm for a sustainable urban stormwater management strategy. Deviating from the traditional rapid draining approach, the new paradigm calls for the use of natural systems, such as soil and vegetation, as part of the urban runoff control strategy. It has become a widespread focus in urban water management research and practices globally. In this Special Issue reprint, there are 13 original scientific articles that address the different related urban runoff control issues. We are happy to see that all papers presented findings characterized as innovative and methodologically new. We hope that the readers can enjoy and learn deeply about urban runoff control and sponge city construction using the published material, and we hope that sharing of the researches results with the scientific community, policymakers and stakeholders can prompt the urban runoff control and sponge city construction globally
Variation of soil suction and application of remote sensing in evaluating unsaturated soil behavior within vadose zone
Moisture movement in pavements and road embankments is receiving more attention in pavement and geotechnical engineering. Water from rainfall is the primary source of moisture in soils. Following a rainstorm event, large quantities of moisture can be absorbed by the soil when the water migrates into the soil mass. The passage of moisture has an impact on the mechanical performance and functionality of the pavement infrastructure. When the pavement infrastructure is built on expansive soils, water flow can cause damage to pavements due to the swelling and shrinking of expansive soils through adsorption and desorption of moisture. Such damage can result in severe financial loss; in fact, the estimated yearly cost of damage from expanding soil problems is $2.3 billion in the United States. Oklahoma contains large expanses of medium to highly expansive clays. The state's largest cities are located in these areas, and significant and costly highway systems have been built to support the population density. These areas have relatively high average annual precipitation, which worsens the expansive clay problems. The swelling or shrinking of expansive clays causes distortion and cracking in pavements, reducing pavement service life. Thus, it is critical to understand how water moves in road embankments of expansive soils subjected to seasonal rainfall and to predict the vertical movement of pavements built on expansive soils. This study used Oklahoma Mesonet measurements to develop a data-driven statistical model for estimating soil diffusivity and soil suction in order to predict the movement of expansive soils over time. The first component of the study used unsupervised learning and a nonlinear least squares model to estimate soil diffusivity. The second component of the study presents a mechanistic-numerical model for predicting equilibrium suction that considers the diffusion coefficient's effects and uses surface field suction measurements. The final component of the study utilized Interferometric Synthetic Aperture Radar (InSAR) technique for effective displacement monitoring using time series of SAR data. The study investigated the performance of moisture barriers on two state highways in Oklahoma, where expansive soils are a major problem
New innovations in pavement materials and engineering: A review on pavement engineering research 2021
Sustainable and resilient pavement infrastructure is critical for current economic and environmental challenges. In the past 10 years, the pavement infrastructure strongly supports the rapid development of the global social economy. New theories, new methods, new technologies and new materials related to pavement engineering are emerging. Deterioration of pavement infrastructure is a typical multi-physics problem. Because of actual coupled behaviors of traffic and environmental conditions, predictions of pavement service life become more and more complicated and require a deep knowledge of pavement material analysis. In order to summarize the current and determine the future research of pavement engineering, Journal of Traffic and Transportation Engineering (English Edition) has launched a review paper on the topic of “New innovations in pavement materials and engineering: A review on pavement engineering research 2021”. Based on the joint-effort of 43 scholars from 24 well-known universities in highway engineering, this review paper systematically analyzes the research status and future development direction of 5 major fields of pavement engineering in the world. The content includes asphalt binder performance and modeling, mixture performance and modeling of pavement materials, multi-scale mechanics, green and sustainable pavement, and intelligent pavement. Overall, this review paper is able to provide references and insights for researchers and engineers in the field of pavement engineering
Planning For The Future: Framework Towards Achieving Co-benefits Through Beneficial Management Practices In The Credit Valley Watershed, Ontario
As the population increases, development pressures, especially in large urban centers, have created a lot of stress on ecosystems, and the ecosystem functions and services that they provide. Issues such as loss of wetland and paving over pervious surfaces has led to increased runoff, low infiltration rates and degradation of the quality of source and non-point source water. Roads, parking lots and other forms of impervious cover are the most significant contributors to stormwater runoff. Effective stormwater management is therefore crucial in such urbanized areas. Low Impact Development (LID) is an innovative stormwater management design philosophy and approach that is closely modeled after nature. Its main goal is to manage rainfall at the source using uniformly distributed, decentralized units such as permeable pavement, bioswales and green roofs. . The principle of LID is to mimic a site's pre-development hydrology by using design techniques that infiltrate, filter, store, evaporate and detain runoff close to the source. The term 'Green Infrastructure' is also used when referring to LID. LID can be used individually or incorporated into conventional stormwater management systems to achieve maximum benefits. Human health and well-being are fundamentally dependent on the services provided by the ecosystems that surround us. The field of ecohealth attempts to make this connection and use it to improve public health, promote resilient communities, and create more sustainable environments. This paper attempts to analyze the connections between three selected Low Impact Development and its effects on the ecosystem services that ultimately affect the health and wellbeing of humans in the Credit River watershed in Southern Ontario, Canada. Ecohealth theories developed by the Millennium Ecosystem Assessment (MEA) (2005; 2003) and the cascade model of ecosystem services (Haines-Young & Potschin, 2010; Braat & de Groot, 2012; Potschin & Haines-Young, 2010) were used to help develop and illustrate the concepts and relationships being researched
Determining Additional Modulus of Subgarde Reaction Based on Tolerable Settlement for the Nailed-slab System Resting on Soft Clay.
Abstract—Nailed-slab System is a proposed alternative
solution for rigid pavement problem on soft soils. Equivalent
modulus of subgrade reaction (k’) can be used in designing of
nailed-slab system. This modular is the cumulative of modulus of
subgrade reaction from plate load test (k) and additional
modulus of subgrade reaction due to pile installing (∆∆∆∆k). A recent
method has used reduction of pile resistance approach in
determining ∆∆∆∆k. The relative displacement between pile and soils,
and reduction of pile resistance has been identified. In fact,
determining of reduction of pile resistance is difficult. This paper
proposes an approach by considering tolerable settlement of rigid
pavement. Validation is carried out with respect to a loading test
of nailed-slab models. The models are presented as strip section
of rigid pavement. The theory of beams on elastic foundation is
used to calculate the slab deflection by using k’. Proposed
approach can results in deflection prediction close to observed
one. In practice, the Nailed-slab System would be constructed by
multiple-row piles. Designing this system based on one-pile row
analysis will give more safety design and will consume less time
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