This paper examines the state of practice of the design and construction of excavations in soft soils. The review is based primarily on the author's experience, published case histories, and discussions with colleagues involved in the design and construction of excavations in soft soils. It is not a survey of current practices, because such a survey would not be practicable, or even useful, because of many variations in local practices. The paper examines major milestones in the development of the design and construction of excavations in soft soils, and reviews recent developments and trends in design and construction practices.
Traditionally, the design and construction of excavations is handled contractually as a design-build contract, with the responsibility for the design and construction of the shoring system delegated to the contractor. However, new developments in analytical design tools and construction methods, as well as wider recognition of the potential legal consequences of the impacts of excavation-induced deformations on existing structures, and the need to address these issues in advance of construction, is leading to new approaches in the design and construction of excavations in general, and for soft soils in particular. Recent innovations in construction methods, such as the introduction of deep-soil mixing and jet grouting, are providing greater flexibility in the design and construction of excavations for deformation control. This paper reviews these developments and summarizes data from case histories to illustrate practical application of these new methodologies and construction techniques for the design and construction of excavations in soft soils.
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Author: W. Allen Marr and Martin Hawkes | Size: 722 KB | Format:PDF | Quality:Unspecified | Publisher: ASCE | Year: 2010 | pages: 19
Many structures located close to excavations are damaged by excessive ground movements during construction. This is partly due to limitations of commonly used methods to design the excavation support system. The authors propose using a displacement-based design method that focuses on designing to keep movements within allowable values. A step-by-step approach for the method is described and illustrated for a deep excavation into soft clay.
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Measured performance of a 26 m deep top-down excavation in downtown Shanghai
Author: Yong Tan and Mingwen Li | Size: 3.9 MB | Format:PDF | Quality:Unspecified | Publisher: anadian Geotechnical Journal | Year: 2011 | pages: 16
Via a long-term comprehensive instrumentation program, the performance of a 26 m deep metro station excavation
constructed by the top-down method in downtown Shanghai was extensively examined. The measured excavation responses
included diaphragm wall deflections, wall settlements, ground settlements, uplifts of interior steel columns, axial
forces of propping struts, groundwater table levels, and settlements of adjacent buildings and utility pipelines. Based on the
analyses of field data, the following major findings were obtained: (i) the concrete struts along with the floor slabs effectively
suppressed later wall movements and consequently reduced the chance that the maximum wall deflections would occur
above the excavation surfaces, (ii) with the progress of excavation to a lower depth, the diaphragm walls underwent a
serrated settlement pattern over time, (iii) no significant post-excavation wall deflection occurred, (iv) the relationship between
the interior column uplifts and the maximum wall deflections can be described by a linear equation, and (v) most system
loads due to soil removal were carried by the concrete struts along with the floor slabs. The struts sustained mainly the
released earth pressures due to the exposure of the adjacent portions of diaphragm walls, and the soil removal distant from
the struts imposed limited effects on the strut axial forces.
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Gilbert Strang's textbooks have changed the entire approach to learning linear algebra -- away from abstract vector spaces to specific examples of the four fundamental subspaces: the column space and nullspace of A and A'.
Introduction to Linear Algebra, Fourth Edition includes challenge problems to complement the review problems that have been highly praised in previous editions. The basic course is followed by seven applications: differential equations, engineering, graph theory, statistics, fourier methods and the FFT, linear programming, and computer graphics.
Thousands of teachers in colleges and universities and now high schools are using this book, which truly explains this crucial subject.
Chapter 1: Introduction to Vectors; Chapter 2: Solving Linear Equations; Chapter 3: Vector Spaces and Subspaces; Chapter 4: Orthogonality; Chapter 5: Determinants; Chapter 6: Eigenvalues and Eigenvectors; Chapter 7: Linear Transformations; Chapter 8: Applications; Chapter 9: Numerical Linear Algebra; Chapter 10: Complex Vectors and Matrices; Solutions to Selected Exercises; Final Exam. Matrix Factorizations. Conceptual Questions for Review. Glossary: A Dictionary for Linear Algebra Index Teaching Codes Linear Algebra in a Nutshe
the book together with the solution manual
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Metal fatigue analysis handbook : practical problem-solving techniques for computer-aided engineering
Author: Yung-Li Lee; Mark E Barkey; Hong-Tae Kang | Size: 10.3 MB | Format:PDF | Quality:Unspecified | Publisher: Butterworth-Heinemann | Year: 2012 | pages: 633 | ISBN: 9780123852045
Understand why fatigue happens and how to model, simulate, design and test for it with this practical, industry-focused reference
Written to bridge the technology gap between academia and industry, the Metal Fatigue Analysis Handbook presents state-of-the-art fatigue theories and technologies alongside more commonly used practices, with working examples included to provide an informative, practical, complete toolkit of fatigue analysis.
Prepared by an expert team with extensive industrial, research and professorial experience, the book will help you to understand:
Critical factors that cause and affect fatigue in the materials and structures relating to your work
Load and stress analysis in addition to fatigue damage-the latter being the sole focus of many books on the topic
How to design with fatigue in mind to meet durability requirements
How to model, simulate and test with different materials in different fatigue scenarios
The importance and limitations of different models for cost effective and efficient testing
Whilst the book focuses on theories commonly used in the automotive industry, it is also an ideal resource for engineers and analysts in other disciplines such as aerospace engineering, civil engineering, offshore engineering, and industrial engineering.
The only book on the market to address state-of-the-art technologies in load, stress and fatigue damage analyses and their application to engineering design for durability
Intended to bridge the technology gap between academia and industry-written by an expert team with extensive industrial, research and professorial experience in fatigue analysis and testing
An advanced mechanical engineering design handbook focused on the needs of professional engineers within automotive, aerospace and related industrial disciplines
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Conventional methods used for the design of anchored sheet pile walls are based on the lateral force and moment equilibrium
of active and passive earth pressures and anchor force. Although it has been known for decades that the stress concentration occurs around
the anchor level because of the restricted wall movements, this stress concentration is not considered in determining the lateral earth pressures.
A parametric study using conventional and numerical methods was performed to investigate the behavior of single-level anchored sheet
pile walls, and the lateral earth pressures, wall bending moments, and anchor forces were analyzed. The study results indicate that the conventional
methods for the conditions considered and cases studied overestimate the wall bending moments, whereas the anchor forces are underestimated.
New lateral earth pressure coefficients that consider the stress concentration around the anchor level were developed and proposed to
be used in the design of single-level anchored sheet pile walls to provide more realistic earth pressure distributions acting on the wall and to
obtain more accurate wall designs.
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Posted by: freequo - 05-13-2013, 07:39 AM - Forum: Archive
- No Replies
Article/eBook Full Name: Soil Mechanics
Author(s): Roberto Nova
Edition: 1st
Publish Date: 2010
ISBN: 1848211025
Published By: Wiley
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Despite a prolonged slump in the housing market, the demand for residential green building remains strong. More than ever, professionals need reliable information about how to construct or retrofit livable, sustainable, and economical homes. With Fundamentals of Sustainable Dwellings, Avi Friedman provides that resource. While other books on residential green building are often either superficial or overly technical, Friedman gets it just right, delivering an illustrated, accessible guide for architects, developers, home builders, codes officials, and students of architecture and green design.
Friedman charts a new course for residential building—one in which social, cultural, economic, and environmental values are part of every design decision. The book begins with a concise overview of green building principles, covering topics such as sustainable resources and common certification methods. Each following chapter examines a critical aspect of green home construction, from siting to waste management options. Friedman provides basics about energy-efficient windows and heating and cooling systems. And he offers innovative solutions like edible landscaping and green roofs.
Friedman knows that in green building, ideas are only as good as their execution. So in each chapter valuable data is assembled and a contemporary project in which designers strove to achieve sustainability while adhering to real-world constraints is featured. The result is a practical guide for every professional in the burgeoning field of residential green building.
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In this study, case study about excavation stabilised using anchors and
high pressure injectionis presented. The land of the project was located in the
northern zone of Tehran with shallow water table. Despite of dewatering operation,
the existence of groundwaterwas still a challenging issue concerning the construction
process.According to the pull-out tests, the gravity-grouted anchors could not satisfy
the design criteria. Therefore, the post-grouting method was employed to increase the
tensile capacity of anchors by enlarging the grout body of straight shafted gravity
grouted anchors. Finally, the loading tests were conducted and anchors locked-off at
75% of designed loads. It should be mentioned that the cast-in place concrete piles
were constructed around the excavation zone as the soldier beams. Satisfactory post
construction performance of this project proves the successful application of 3900 m
of ground anchors in 2800 m2 of excavation wall for this deep excavation.
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In anchor pullout design, conservative soil and rock shear strength parameters are usually adopted. Presumptive values of soil/grout and rock/grout bond strength are available in different design manuals. In this study, in-situ pullout test data for anchors in soil and rock type worldwide were collected from published sources and information provided by specialty wall contractors. The measured pullout test data were compared to estimated pullout resistance using the Post-Tensioning Institute (PTI) presumptive bond strength values. Statistical analysis was performed to determine the probability of success and the corresponding reliability indices using the minimum, average and maximum PTI ground/anchor bond strength values for cohesive soils, cohesionless soils and different rock types. A minimum safety factor of 2 recommended by the PTI to the ground/grout bond strength was found not conservative where the maximum presumptive bond strength values were used in clays and sands, and the average and the maximum presumptive bond strength values were used in rocks. Based on the results of this study, an average minimum factor of safety was recommended for ground/grout bond strength.
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