Design of dynamic compaction

1992 ◽  
Vol 29 (5) ◽  
pp. 796-802 ◽  
Author(s):  
Chaim J. Poran ◽  
Jorge A. Rodriguez
Keyword(s):  
Design Method ◽  
Volumetric Strain ◽  
Empirical Method ◽  
Dynamic Compaction ◽  
Soil Conditions ◽  
Simple Relationship ◽  
Cohesionless Soils ◽  
Design Engineers ◽  
Model Study ◽  
Key Words Dynamic

In recent years dynamic compaction (DC) has become a popular method for deep improvement of loose cohesionless soils and man-made fills of disposed waste and rubble. One of the main problems facing design engineers and contractors is the assessment of the number of tamper drops, grid spacing, and layout of passes required to attain satisfactory improvement depth in the soil strata. Many DC sites have irregular subsurface conditions where it is difficult to interpret results from site exploration and verification tests. The industry has long been using a simple relationship to estimate the depth of improvement (influence depth). The estimates obtained from that empirical method may vary considerably and in many cases may be rendered useless for DC design. The paper describes a new, rational, and more comprehensive DC design method based on results from an extensive experimental model study of impact response in dry sand. Analysis of normalized impact energy and the resulting densification in the sand in terms of normalized dimensions of volumetric strain contours shows unique correlations that are used for the proposed design method for dynamic compaction in unsaturated sandy soils. Data from several DC sites fit well with the new method. With future studies of field results the proposed approach could eventually be calibrated and used for other types of soil conditions. Key words : dynamic compaction, design, impact, sandy soil, energy, plastic strains

scholarly journals Two-Dimensional Numerical Modeling of Flow in Physical Models of Rock Vane and Bendway Weir Configurations

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 458
Author(s):  
Drew C. Baird ◽  
Benjamin Abban ◽  
S. Michael Scurlock ◽  
Steven B. Abt ◽  
Christopher I. Thornton
Keyword(s):  
Numerical Modeling ◽  
Physical Model ◽  
Numerical Models ◽  
Hydraulic Performance ◽  
Physical Models ◽  
Protection Measures ◽  
Design Engineers ◽  
Model Study ◽  
Study Results ◽  
Wide Range

While there are a wide range of design recommendations for using rock vanes and bendway weirs as streambank protection measures, no comprehensive, standard approach is currently available for design engineers to evaluate their hydraulic performance before construction. This study investigates using 2D numerical modeling as an option for predicting the hydraulic performance of rock vane and bendway weir structure designs for streambank protection. We used the Sedimentation and River Hydraulics (SRH)-2D depth-averaged numerical model to simulate flows around rock vane and bendway weir installations that were previously examined as part of a physical model study and that had water surface elevation and velocity observations. Overall, SRH-2D predicted the same general flow patterns as the physical model, but over- and underpredicted the flow velocity in some areas. These over- and underpredictions could be primarily attributed to the assumption of negligible vertical velocities. Nonetheless, the point differences between the predicted and observed velocities generally ranged from 15 to 25%, with some exceptions. The results showed that 2D numerical models could provide adequate insight into the hydraulic performance of rock vanes and bendway weirs. Accordingly, design guidance and implications of the study results are presented for design engineers.

Design engineers’ perception of health and safety and its impact in the design process

2016 ◽  
Vol 23 (1) ◽  
pp. 40-59 ◽  
Author(s):  
Susan Morrow ◽  
Billy Hare ◽  
Iain Cameron
Keyword(s):  
Design Process ◽  
Design Method ◽  
Health And Safety ◽  
Design Activity ◽  
Content Type ◽  
Safety Issues ◽  
Design Engineers ◽  
Junior Staff ◽  
Safety Considerations ◽  
Perception Of Health

Purpose – The purpose of this paper is to consider design engineers’ perception of health and safety and its impact on their behaviour during design activity. The study presents three types of design engineers each, exhibiting particular tendencies when faced with health and safety considerations during design. The discovery of these tendencies pose important implications for education and professional institutions and practical measures are suggested to help design engineers manage their tendencies to be more conducive to ensuring improved health and safety performance. Design/methodology/approach – An exploratory design method was used – grounded theory, to include 13, in-depth, one-to-one interviews with design engineers, representing junior staff, middle and senior management. Findings – The paper provides empirical insights about how designers think and behave when asked to consider health and safety issues during the design process. It identifies three group types of designers: doers, receivers and givers, who will exhibit their particular tendencies based on how they view and understand the term health and safety. Research limitations/implications – The data obtained were from design engineers only, and therefore the research results may lack generalisability. Therefore, researchers are encouraged to test the proposed propositions. Practical implications – The paper includes implications for those involved in the creation and development of designers e.g., educators and professional bodies. The data forms the basis for helping designers to manage their perceptions towards the term health and safety and thus, their tendencies exhibited in their behaviour. Originality/value – This paper contributes to new understanding of designers’ behaviour and considers the significance of how designers’ views of health and safety will influence their behaviour.

Flexible Pavement Overlays: The State Experience

1997 ◽  
Vol 1568 (1) ◽  
pp. 139-147
Author(s):  
Peter E. Sebaaly ◽  
Stephen Lani ◽  
Sohila Bemanian ◽  
Christopher Cocking
Keyword(s):  
Design Method ◽  
Design Procedure ◽  
Survey Method ◽  
Department Of Transportation ◽  
Significant Discrepancy ◽  
Design Engineers ◽  
Routine Basis ◽  
Final Design ◽  
Overlay Design ◽  
Nondestructive Testing Method

The design and construction of flexible overlays has become a popular exercise. However, there is not a simple, straightforward, and yet reliable design procedure that the design engineer can implement on a routine basis. The data needed for overlay design are not easily accessible to the design engineer, and yet the accessible data are not fully reliable in most cases. The process by which the design engineers at the Nevada Department of Transportation handle overlay design is presented. The various steps followed and the obstacles that the design engineer encounters in the search for the necessary data and the final design process are described. Major assumptions must be made along the way that could significantly affect the final design. Three case studies are presented. Each project was designed using three different design methods, including the AASHTO nondestructive testing method, the AASHTO condition survey method, and the Nevada Department of Transportation (NDOT) mechanistic overlay design method. All three methods used the same data gathered by the design engineer for each project. The analysis indicates that there is a significant discrepancy between the two AASHTO methods, whereas the NDOT method and the AASHTO condition survey method agreed on one project.

scholarly journals Development of a Design Catalog for Bonded Concrete Overlay Pavements Considering the Regional Characteristics of Korea

2021 ◽  
Vol 13 (17) ◽  
pp. 9876
Author(s):  
Hae-Won Park ◽  
Jin-Seok Seo ◽  
Jae-Hoon Lee ◽  
Jin-Hoon Jeong
Keyword(s):  
Design Method ◽  
Empirical Method ◽  
Climatic Conditions ◽  
Traffic Volume ◽  
Concrete Pavement ◽  
Element Analysis ◽  
Concrete Overlays ◽  
Volume Elastic Modulus ◽  
Bonded Concrete Overlay ◽  
Empirical Design

The design of overlay pavement in Korea, using the American empirical method, does not consider the unique Korean climate, pavement material, and traffic conditions. Therefore, in this study, a mechanistic–empirical design catalog for bonded concrete overlays (BCO) that are appropriate for Korean pavement conditions was developed. First, the thickness of the new pavement slab was determined through the Korean pavement design method, which uses a mechanistic–empirical design program according to the traffic volume of the region with the worst climatic conditions in Korea. Then, finite element analysis models of new jointed concrete and BCO pavements were developed to determine the BCO thickness by adjusting it until the stress–strength ratio of an existing slab of BCO pavement was equal to that of a new concrete pavement slab. By repeating this procedure, a design catalog was developed for the sustainable management of concrete pavement according to the traffic volume, elastic modulus, and thickness of the existing slab after milling. The appropriateness of the BCO thickness predicted by the design catalog was verified by comparing it with that predicted by other design methods.

scholarly journals On Some Methods in Safety Evaluation in Geotechnics

2015 ◽  
Vol 37 (2) ◽  
pp. 17-32 ◽  
Author(s):  
Wojciech Puła ◽  
Łukasz Zaskórski
Keyword(s):  
Design Method ◽  
Safety Evaluation ◽  
Short Review ◽  
Cohesionless Soils ◽  
Reliability Based Design ◽  
Working Stress ◽  
Rigid Pile ◽  
Complementary Role ◽  
Capacity Calculation ◽  
Reliability Methods

Abstract The paper demonstrates how the reliability methods can be utilised in order to evaluate safety in geotechnics. Special attention is paid to the so-called reliability based design that can play a useful and complementary role to Eurocode 7. In the first part, a brief review of first- and second-order reliability methods is given. Next, two examples of reliability-based design are demonstrated. The first one is focussed on bearing capacity calculation and is dedicated to comparison with EC7 requirements. The second one analyses a rigid pile subjected to lateral load and is oriented towards working stress design method. In the second part, applications of random field to safety evaluations in geotechnics are addressed. After a short review of the theory a Random Finite Element algorithm to reliability based design of shallow strip foundation is given. Finally, two illustrative examples for cohesive and cohesionless soils are demonstrated.

scholarly journals Formalization of Low-frequency Rectangular Electrical Connectors Design Method

2019 ◽  
Author(s):  
Владимир Аверченков ◽  
Vladimir Averchenkov ◽  
Алексей Вилюха ◽  
Alexey Viluykha ◽  
Михаил Рытов ◽  
...  
Keyword(s):  
Design Process ◽  
Design Method ◽  
Low Frequency ◽  
Empirical Method ◽  
Design System ◽  
Development Trends ◽  
Technological Preparation ◽  
Cad Cam ◽  
The Moment ◽  
Electrical Connectors

The article deals with the design process of low-frequency rectangular electrical connectors and determining the position CAD/CAE-systems in it. The review of the actual literature shows that development trends of design and technological preparation of low-frequency rectangular electrical connectors production mean using CAD/CAM/CAE-systems. But at the moment these systems are used for solving partial issues. The authors formalize the empirical method of the design and systemize the factors, which influence the design process. As a result of the mentioned above actions, the working algorithm of the multipurpose CAD/CAE electrical connectors design system was obtained. The results of the research were applied to automize the design process of connectors housings.

scholarly journals Use of mechanistic-empirical method of pavement design for performance sensitivity analysis to asphalt pavement fatigue

2021 ◽  
Vol 26 (3) ◽  
Author(s):  
Natalia Assunção Brasil Silva ◽  
Taciano Oliveira da Silva ◽  
Heraldo Nunes Pitanga ◽  
Geraldo Luciano de Oliveira Marques
Keyword(s):  
Design Method ◽  
Permanent Deformation ◽  
Empirical Method ◽  
Material Behavior ◽  
Experimental Program ◽  
Data Sets ◽  
Statistical Regression ◽  
Wide Range ◽  
Number Of Cycles

ABSTRACT In the new Brazilian mechanistic-empirical design method of asphalt pavements, MeDiNa, the characterization of permanent deformation (PD) for the selection of soils and gravel is based on tests performed with at least 150,000 loading cycles for each of the nine specimens indicated in the DNIT standard. Despite providing information about the material behavior under a wide range of testing conditions, the experimental program related to these PD characterizations is time consuming and it is believed that it can be optimized. This paper evaluates the influence of the number of loading cycle applications on the characterization of the materials. For this purpose, seven materials were analyzed at their optimum moisture content (OMC) and one of them was also compacted in a condition above the OMC, in a total of eight data sets. Statistical regression analyzes were performed to identify the parameters of the predictive model for different numbers of cycles and the PD predictions for the different materials were compared. From these results, simulations were performed in the MeDiNa software to predict the performance of the materials. Four different N values were evaluated, considering 150,000 cycles as reference: discarding the 500 first cycles, but considering the PD accumulated in that interval; discarding the 500 first cycles and considering the PD accumulated in that interval; final N of 80,000; and final N of 100,000. For the analyzed materials, no significant differences were observed in the PD prediction, even considering tests with 50,000 or 70,000 cycles less than the 150,000 cycles required in the standard. This indicates that, although characterization is recommended following standardized procedures, the experimental program of the current PD standard can possibly be significantly optimized by reducing the number of cycles applied to materials in laboratory tests. This possibility must be analyzed for each material.

scholarly journals Kandungan Flavonoid dan Serat Sesbania grandiflora pada Berbagai Umur Bunga dan Polong

2018 ◽  
Vol 9 (2) ◽  
pp. 122-130
Author(s):  
Eko Setiawan
Keyword(s):  
Dietary Fiber ◽  
Design Method ◽  
Soil Conditions ◽  
Vegetable Production ◽  
Harvest Time ◽  
Sesbania Grandiflora ◽  
Randomized Design ◽  
Two Factors ◽  
Dry Soil ◽  
Completely Randomized Design

ABSTRACTThe vegetable production in Madura islands is very limited due to dry soil conditions. The turi tree (Sesbania grandiflora) planted in Madura as barrier rice fields has the potential to be optimized as a source of vegetable. The objective of the study was to determine flavonoid and dietary fiber contents in flowers and fruits/pods of red and white turi that are picked at different ages. The research was conducted in December 2016 to March 2017 at Bangkalan. The study was arranged is Completely Randomized Design method with two factors and three replications. First factor was namely flower (red and white turi), and second factor is harvest time (turi flowers are harvested at 1, 2, 3, 4, 5, and 6 days; while the fruits/pods are harvested at 1, 2, 3, 4, 5, and 6 weeks after anthesis). The results showed that flavonoid contents in white turi flower ranged from 12.58-211.35 mg.100 g-1, whereas flavonoid contents in red flower ranged from 17.32- 30.05 mg.100 g-1. The highest flavonoid content is produced at 4-day-old flowers for white turi, and 4-5 day-old flowers for red flowers. The dietary fiber content in turi flower was higher in red than white flower ranged from 2.11-2.85% and 1.82-2.55%, respectively. The amount of dietary fiber in the fruits/pods was low, range from 0.013-0.686% and 0.009-0.722% in white and red turi, respectively. The flowers of turi should be consumed at 4-5 day-old flowers, while fruits/pods at 1-3 weeks after anthesis.Keywords: anthesis, functional vegetable, harvest time, Madura islandABSTRAKProduksi tanaman sayuran di Pulau Madura sangat terbatas karena kondisi tanah yang kering. Pohon turi (Sesbania grandiflora) yang ditanam sebagai pembatas tegalan dan sawah di Madura berpotensi untuk dioptimalkan sebagai sumber bahan sayuran. Penelitian bertujuan mengetahui kandungan serat dan flavonoid pada bunga dan buah/polong turi warna merah dan putih yang dipetik pada umur yang berbeda. Penelitian dilaksanakan di Bangkalan pada bulan Desember 2016 sampai Maret 2017. Penelitian menggunakan Rancangan Acak Lengkap dengan dua faktor dan diulang 3 kali. Faktor pertama adalah jenis bunga (turi bunga merah dan bunga putih), sedangkan faktor kedua adalah umur panen (bunga turi dipanen pada umur 1, 2, 3, 4, 5, dan 6 hari; sedangkan buah (polong) dipanen pada umur 1, 2, 3, 4, 5, dan 6 minggu setelah bunga mekar). Hasil penelitian menunjukkan kandungan flavonoid pada bunga turi putih berkisar antara 12.58-21.35 mg.100 g-1, sedangkan pada turi bunga merah kandungan flavonoid berkisar 17.32-30.05 mg.100 g-1. Kandungan flavonoid tertinggi dihasilkan pada bunga umur 4 hari untuk turi putih, dan bunga umur 4-5 hari untuk turi merah. Kandungan serat turi merah lebih tinggi dibandingkan dengan turi putih masing-masing dengan kisaran antara 2.11-2.85% dan 1.82-2.55%. Kandungan serat pada buah/polong turi sangat rendah berkisar antara 0.013-0.686% pada turi putih dan sebesar 0.009-0.722% pada turi merah. Bunga turi sebaiknya dikonsumsi pada umur 4-5 hari, sedangkan buah/polong pada umur 1-3 minggu setelah anthesis.Kata kunci: anthesis, Pulau Madura, sayuran fungsional, umur panen

Effect of particle size and strain conditions on the strength of crushed basalt

1983 ◽  
Vol 20 (4) ◽  
pp. 706-717 ◽  
Author(s):  
Mosaid Al-Hussaini
Keyword(s):  
Particle Size ◽  
Stress Level ◽  
Level Density ◽  
Triaxial Compression ◽  
Volumetric Strain ◽  
Confining Pressure ◽  
Strain Diagram ◽  
Compression Tests ◽  
Cohesionless Soils ◽  
Lower Shear

This paper describes the results of an investigation carried out to study the influence of particle size, stress level, density, method of consolidation, and strain conditions on the strength and compressibility of crushed basalt. All specimens were prepared at medium or high density, consolidated isotropically or under K0 consolidation, and sheared under effective confining pressure ranging from 443 to 2297 kPa. The material used in the test program had a straight line grain size distribution with maximum particle size ranges from 0.63 to 76.2 mm and minimum particle size equivalent to No. 30 U.S. standard sieve size:The tests indicated that an increase in the particle size (i.e., gradation) increases the strength and decreases the axial and the volumetric strain at failure. The study indicated further that the crushed basalt under triaxial compression has a lower shear strength than when sheared under plane strain conditions. Particles crushed were significantly influenced by the stress level and gradation and to a lesser degree by density of material. Keywords: cohesionless soils, density (mass/volume), shear tests, stress–strain diagram, compression tests, rockfill dams.

A neural network framework for mechanical behavior of unsaturated soils

2003 ◽  
Vol 40 (3) ◽  
pp. 684-693 ◽  
Author(s):  
Ghassem Habibagahi ◽  
Alireza Bamdad
Keyword(s):  
Neural Network ◽  
Mechanical Behavior ◽  
Unsaturated Soils ◽  
Axial Strain ◽  
Volumetric Strain ◽  
Constitutive Law ◽  
Soil Conditions ◽  
Neural Network Approach ◽  
Network Simulations ◽  
Multilayer Perceptron Network

In this paper, a neural network approach is used to describe the mechanical behavior of unsaturated soils. A sequential architecture was chosen for the network, that is, a multilayer perceptron network with feedback capability. The input layer consisted of nine neurons, where six of them represented the initial soil conditions and the remaining three neurons were continuously updated for each increment of axial strain based on outputs from the previous increment. The output layer consisted of three neurons representing values of deviatoric stress, volumetric strain, and change in suction at the end of each increment. Next, a database was developed from triaxial test results available in the literature. The database was used to train and test the network. Neural network simulations were compared with experimental results. The comparison indicates the good performance of the proposed network for predicting the mechanical behavior of unsaturated soils. Moreover, the trained network was employed to simulate other stress paths not present in the database to model the so-called "collapse phenomena." The results were promising.Key words: unsaturated soil, neural network, stress–strain, collapse, modeling, constitutive law.

Sign in / Sign up

Export Citation Format

Share Document