The Superpave Mix Design System: Anatomy of a Research Program
Author: McDaniel, Rebecca S Leahy, Rita B Huber, Gerald A Moulthrop, James S Ferragut, Ted | Size: 2.62 MB | Format:PDF | Quality:Original preprint | Publisher: Transportation Research Board | Year: 2011 | pages: 185 | ISBN: -
The asphalt research program conducted as part of the Strategic Highway Research Program was the most focused asphalt research program ever. Intense research activity over a nominal five-year period at a cost of $50 million dollars led to sweeping changes in how asphalt materials are specified, tested and designed. The products of this research, known collectively as the Superpave mix design system or simply Superpave, are used across the U.S. and internationally. This report describes how such a large-scale research effort was conceived, funded, and managed. It outlines the research and implementation efforts that brought the products into routine use. Lastly, it summarizes some of the key lessons learned in the process of conducting such a large-scale program. The findings outlined in this report were garnered through interviews with over 70 people who were involved in the research and implementation efforts as well as reviewing reports, letters, diaries, meeting minutes and other documents.
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Seismic Design of Geosynthetic-Reinforced Soil Bridge Abutments with Modular Block Facing
Author: Helwany, Sam Wu, Jonathan Meinholz, Philip | Size: 28.47 MB | Format:PDF | Quality:Original preprint | Publisher: Transportation Research Board | Year: 2012 | pages: 260 | ISBN: -
A geosynthetic-reinforced soil (GRS) mass is formed by placing closely-spaced layers of polymeric geosynthetic reinforcement in a soil mass during soil placement. The reinforcement in a GRS mass serves primarily to improve engineering properties of soil. The concept of GRS has been used successfully over the past few decades in many transportation facilities, including retaining walls, embankments, roadways, and steepened slopes. Tests and in-service installations have shown that GRS systems, particularly GRS walls with modular-block facing, are structurally sound, easy and fast to construct, and low cost compared to other designs. Interest in using GRS design for bridge abutments and approaches, in particular, has grown but a lack of rational and reliable design and construction guidelines for such structures has impeded more widespread adoption. NCHRP Report 556, "Design and Construction Guidelines for Geosynthetic-Reinforced Soil Bridge Abutments with a Flexible Facing," was produced as a first step effort toward developing such guidelines. The research described in that report addressed static loading conditions only. NCHRP Project 12-59(01), the subject of this report, was undertaken to develop design and construction guidelines for applications in seismically active regions. The research described here focused on single-span, simply-supported bridges subjected to seismic forces. Current seismic design methods for reinforced soil retaining walls – both pseudo-static methods and displacement methods – have been developed for situations where the self-weight of the soil is the predominant load. For a GRS bridge abutment, however, the abutment’s top surface is intended to provide a foundation of the bridge superstructure. The GRS abutment will be expected not only to maintain its stability as a soil mass but also to bear the additional large sustained and seismic loads associated with the bridge superstructure. The objective of this research was to extend the earlier research reported in NCHRP Report 556 to consider seismic loading conditions and thereby provide a more comprehensive basis for developing rational guidelines for design and construction of GRS abutments and approaches with modular-block facing.
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Can somebody share the following papers to me? I really need them.
1. Design method for stability analysis of the slope with landing pier
(Soils and Foundations, vol 19, No.4, pp 43-57)
2. Design method for the stabilizing piles against landslide-one row of piles
(Soils and Foundations vol 21, No.1, pp 21-27)
3. Extended design method for multi row stabilizing piles against landslide
(Soils and Foundations Vol.22, No.1, pp1-13)
Author: McCahon, Mary E Sutherland, Larry Shaup, Steven | Size: 3.57 MB | Format:PDF | Quality:Original preprint | Publisher: Transportation Research Board | Year: 2012 | pages: 107 | ISBN: -
This report contains guidelines for the design and management of historic roads. They are intended to demonstrate how the inherent flexibility in the current policies, manuals, criteria, rules, standards, and data sets that underlie the transportation planning and project development process can be used to preserve historic roads and roads in historic districts and settings. The guidance outlines some of the approaches encouraging use of flexibility and how to apply it to develop balanced solutions tailored to all types of projects, from new construction to addressing site specific safety problems. Achieving balanced designs where history matters does not require different or special criteria or policies; the ways to do so efficiently are already in place. It is the practice itself that benefits from recognizing and using available means to craft outcomes that respect and preserve historic significance without compromising safety and operations. This guidance is specific to historic roads and roads in historic settings because they are frequently part of transportation projects, but it is in no way exclusive to them. The approaches described herein are systemic and can be applied to any project involving historic properties or other cultural or environmental considerations.
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Author: Moore, I D Garcia, D Becerril Sezen, H Sheldon, T | Size: 13.41 MB | Format:PDF | Quality:Original preprint | Publisher: Transportation Research Board | Year: 2012 | pages: 388 | ISBN: -
Findings and conclusions of experimental and computational studies are presented regarding the effect of longitudinal bending on joints in rigid (reinforced concrete) and flexible (corrugated steel and thermoplastic) culverts. Two joint types are examined – those releasing the longitudinal bending moments (denoted ‘moment-release joints’) like gasketted bell and spigot joints, and those transferring them (denoted ‘moment-transfer joints’) such as band connections. Structural design requires evaluation of the ability to transfer vertical shear force across moment-release and moment-transfer joints, longitudinal bending moments across moment-transfer joints, and for moment-release joints to accommodate rotations. Both field performance and laboratory experiments are used to evaluate the behavior of jointed pipe systems for four different diameters, two different cover depths, and response to surface loads in a variety of positions. Different approaches are investigated for analysis of the structural behavior of joints to determine thrust, moment and rotation across joints. One approach considering two beams supported by elastic springs is used to develop a simplified design procedure. A second design approach involves finite element analysis using beam-on-elastic-spring modeling. Design examples are presented, and preliminary tests of the capacity of three of the test pipes indicate that these products satisfy the structural design requirements being proposed.
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Mechanically stabilized earth (MSE) walls are retaining walls that rely on internal reinforcement embedded in the backfill for stability. This study addresses methods currently used to assess long-term performance of MSE walls, where "long-term" denotes the period of time from approximately one year after the wall is in service until the end of its design life. The focus of the study is on state and federal agency wall inventories, including methods of inspection and assessment of wall conditions. Information was gathered through a literature review, agency survey, and selected interviews.
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Testing and Inspection Levels for Hot-Mix Asphaltic Concrete Overlays
Author: Russell, J S Hanna, A S Nordheim, E V Schmitt, R L | Size: 1.74 MB | Format:PDF | Quality:Original preprint | Publisher: Transportation Research Board | Year: 2001 | pages: 134 | ISBN: 0309066638
This report contains the findings of a study to develop a rational method for determining the minimum level for both agency and contractor testing and inspection activities necessary to satisfactorily construct hot-mix asphaltic concrete (HMA) overlays using the AASHTO "Quality Assurance Guide Specification" and the AASHTO "Implementation Manual for Quality Assurance" and to apply the findings of this research to other construction activities. The minimum level of testing and inspection is defined in this report as the minimum testing and inspection resources that should be allocated for a given project. Satisfactorily constructing an HMA overlay is defined as meeting the specifications which are, in turn, defined by test properties and compliance measures. The contents of this report, therefore, will be of immediate interest to highway professionals responsible for planning, administering, and financing highway improvements; those concerned with pavement design, management, and performance; as well as those involved in materials and construction issues.
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Elastomeric Bridge Bearings: Recommended Test Methods
Author: Yura, J KUMAR, A Yakut, A Topkaya, C Becker, E Collingwood, J | Size: 3.58 MB | Format:PDF | Quality:Original preprint | Publisher: Transportation Research Board | Year: 2001 | pages: 124 | ISBN: 0309066670
Fifteen tests currently required by the American Association of State Highway and Transportation Officials (AASHTO) for determining the properties of elastomeric bridge bearings were evaluated with respect to their effect on the performance of the bearing. Experimental research was conducted in principally four areas: shear modulus, aging, creep, and low temperature. Theoretical studies were undertaken on the effect of misaligned steel laminates on the stresses and deformation within the elastomeric bearing. It was found that significant misalignments do not have a significant effect on the internal stresses and strains. Crack growth studies established that ozone induced surface cracks or cracks from manufacturing defects on the surface will not propagate significantly into the bearing within its lifetime. Delaminations at the interface of the elastomer and steel laminate were found to be very significant, so bearings with such defects should be rejected. Three new test methods were developed: an inclined compression test, a creep test and a compressive stiffness test. The inclined compression test was developed primarily to determine the shear modulus of the elastomer, but it can also be used to determine the shear bond strength and the compressive stiffness of the bearing. The elimination of eight current test procedures in AASHTO is recommended. New low temperature bearing performance criteria were developed because the current criteria unnecessarily restrict the use of certain elastomeric material.
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This report contains the findings of a study to determine load factors for use in evaluating the load capacity of existing bridges. The report includes recommended values for load factors and presents the methodology and data used to calibrate the factors to provide appropriate safety margins. The material in this report will be of immediate interest to bridge engineers involved in bridge load rating and to engineers interested in the development of load and resistance factor rating procedures.
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Recommended Specifications for Large-Span Culverts
Author: McGrath, T J Moore, I D Selig, E T Webb, M C Taleb, B White, T D Haddock, J E Hand, AJT Fang, H | Size: 865 KB | Format:PDF | Quality:Original preprint | Publisher: Transportation Research Board | Year: 2002 | pages: 148 | ISBN: 030906757X
This report contains the findings of a study to develop recommended design and construction specifications for metal and concrete large-span culverts. The report describes the research effort leading to the recommended specifications and includes information on field-testing and computer modeling. The methodology used to develop simplified design equations is also included. The material in this report will be of immediate interest to specification writers and to engineers concerned with the design and construction of large-span culverts.
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