TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 429: Geotechnical Information Practices in Design-Build Projects addresses how states use geotechnical information in solicitation documents and contracts for design-build highway projects. The report examines current practices regarding the allocation of geotechnical risk and the level of geotechnical information provided wi...

This fall, TRB will release Rockfall: Characterization and Control, which will address rockfall hazard identification and evaluation, investigation process, mitigation options, and maintenance and management programs. The 400 page publication will include a DVD with video clips of rockfall field tests and several historical movies documenting rockfall field activities. Because of the expec...

Roundabouts have seen unprecedented growth across the United States, from just a handful a decade ago to more than 2,000 and counting. National guidance had to keep pace with the needs of states and communities planning and implementing roundabouts, and NCHRP took a lead role.

TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 428: Practices and Procedures for Site-Specific Evaluations of Earthquake Ground Motions identifies and describes current practice and available methods for evaluating the influence of local ground conditions on earthquake design ground motions on a site-specific basis. The report focuses on evaluating the response of soil de...

In regions across the nation, bridge engineers know that the next major seismic event is coming—maybe tomorrow, maybe centuries from now. DOTs have the critical charge of designing for earthquakes and protecting the lives of travelers.

TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 187: Seismic Design of Geosynthetic-Reinforced Soil Bridge Abutments with Modular Block Facing explores design methods and construction guidelines for using geosynthetic-reinforced soil (GRS) systems in bridge abutments in seismically active regions. The report focuses on single-span, simply-supported bridges subjecte...

TRB’s Transportation Research Record: Journal of the Transportation Research Board, No. 2253 consists of eight papers that explore time-dependent structural response of full-depth reclamation, the compactability of recycled concrete aggregate, distressed pavements supported on a base course containing recycled concrete aggregate, continuously reinforced concrete pavement containing recycled con...

TRB’s Transportation Research Record: Journal of the Transportation Research Board, No. 2232 consists of 10 papers that explore management of unsealed gravel roads, assessing potential reactivity of aggregates in presence of potassium acetate deicer, curing conditions on the impact of natural aggregate coatings on concrete performance, polishing tendency of coarse aggregates, resilient modulus ...

TRB’s National Cooperative Highway Research Program (NCHRP) Report 701: Proposed Specifications for LRFD Soil-Nailing Design and Construction contains proposed specifications for the design and construction of soil-nailed retaining structures. The American Association of State Highway and Transportation Officials (AASHTO) Standard Bridge Specifications, the AASHTO Load and Resistance Factor Des...

TRB’s National Cooperative Highway Research Program (NCHRP) Report 697: Design Guidelines for Increasing the Lateral Resistance of Highway-Bridge Pile Foundations by Improving Weak Soils examines guidance for strengthening of soils to resist lateral forces on bridge pile foundations. The report presents computational methods for assessing soil-strengthening options using finite-element analysis...

TRB’s Transportation Research Record: Journal of the Transportation Research Board, No. 2212 contains 13 papers that explore acceptance of geomaterials, water jetting to mitigate defects in drilled shafts, pile load test and implementation of load and resistance factor design specifications, lateral resistance of short rock sockets in weak rock, and field testing of a batter pile group foundati...

TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 418: Developing Production Pile Driving Criteria from Test Pile Data provides information on the current practices used by state transportation agencies to develop pile driving criteria, with special attention paid to the use of test pile data in the process.

TRB’s Transportation Research Record: Journal of the Transportation Research Board, No. 2204 is the second of three volumes that collectively present 90 technical papers pertinent to low-volume roads, 44 by authors from the United States and 46 by authors from 18 other countries. Volume 2 contains 32 papers that address maintenance, stabilization, and geotechnical engineering aspects of low-vol...

TRB’s Transportation Research Record: Journal of the Transportation Research Board, No. 2205 is the third of three volumes that collectively present 90 technical papers pertinent to low-volume roads, 44 by authors from the U.S. and 46 by authors from 18 other countries. Volume 3 contains 31 papers that address materials, and pavement management aspects of low-volume roads.

TRB’s National Cooperative Highway Research Program (NCHRP) Report 675: LRFD Metal Loss and Service-Life Strength Reduction Factors for Metal-Reinforced Systems explores the development of metal loss models for metal-reinforced systems that are compatible with the American Association of State Highway and Transportation Officials' Load and Resistance Factor Design Bridge Design Specifications. ...

TRB’s Transportation Research Record: Journal of the Transportation Research Board, No. 2186 contains 17 papers that explore estimating the resilient modulus of subgrade soils using the falling weight deflectometer, quality management of base materials with seismic methods, characterization of a two-layer soil system, performance-based design of deep foundation systems, analysis method for dril...

TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 351: Precision Statements for AASHTO Standard Methods of Test T 148, T 265, T 267, AND T 283 summarizes the findings of four interlaboratory studies conducted in 2009 and 2010 to develop precision statements for the AASHTO standard methods of measuring length of drilled concrete cores, laboratory determination o...

TRB’s National Cooperative Highway Research Program (NCHRP) Report 676: Intelligent Soil Compaction Systems explores intelligent compaction, a new method of achieving and documenting compaction requirements. Intelligent compaction uses continuous compaction-roller vibration monitoring to assess mechanistic soil properties, continuous modification/adaptation of roller vibration amplitude and fre...

TRB Transportation Research Record: Journal of the Transportation Research Board, No. 2202 consists of 18 papers that explore bridge foundations; concrete bridge decks; assessment and evaluation of bridge extreme events including explosions, wave loading, and earthquakes; bridge management; and bridge seismic analysis.

TRB Transportation Research Record: Journal of the Transportation Research Board, No. 2201 consists of 18 papers that explore bridge scour, nondestructive evaluation of bridges, bridge culverts and soil stabilization and analysis, bridge engineering case studies, and bridge structural health monitoring.

TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 168: Precision Estimates of AASHTO T 180: Moisture-Density Relations of Soils Using a 4.54-kg (10-lb) Rammer and a 457-mm (18-in.) Drop explores an interlaboratory study and data mining of the proficiency sample program to prepare precision estimates for American Association of State Highway and Transportation Officia...

TRB’s Transportation Research Record: Journal of the Transportation Research Board, No. 2170 includes 13 papers that explore data quality assessments for manual pavement condition surveys, success factors of fish passageways, life-cycle assessment of pavement reconstruction options, detecting voids under pavements, model for resilient response of soils resulting from seasonal changes, effect of...

TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 164: Precision Estimates of AASHTO T265: Laboratory Determination of Moisture Content of Soils includes the results of an interlaboratory study to prepare precision estimates for the American Association of State Highway and Transportation Officials (AASHTO) T265 test method used for laboratory determination of moistu...

TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 163: Precision Estimates of AASHTO T267: Determination of Organic Content in Soils by Loss on Ignition includes the results of an interlaboratory study to prepare precision estimates for the American Association of State Highway and Transportation Officials T267 test method used for the determination of organic conten...

TRB’s Transportation Research Record: Journal of the Transportation Research Board, No. 2167 includes 8 papers that explore red mud-based geopolymers, reclaimed asphalt pavement, recycled concrete materials, use of limestone screenings in roadway construction, unbound aggregate performance, and shakedown limit from multistage permanent deformation tests.

TRB’s National Cooperative Highway Research Program (NCHRP) Report 663: Design of Roadside Barrier Systems Placed on MSE Retaining Walls explores a design procedure for roadside barrier systems mounted on the edge of a mechanically stabilized earth (MSE) wall. The procedures were developed following American Association of State Highway and Transportation Officials Load and Resistant Facto...

TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 347: A National Database of Subgrade Soil-Water Characteristic Curves and Selected Soil Properties for Use with the MEPDG explores the creation of a national database of pedologic soil families that contains the soil properties for subgrade materials needed as input to the Mechanistic-Empirical Pavement Design G...

TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 153: A National Database of Subgrade Soil-Water Characteristic Curves and Selected Soil Properties for Use with the MEPDG is the contractor’s final report and Appendices A through D related to NCHRP Research Results Digest 347 with the same title.  NCHRP RRD 347 explores the creation of a national database o...

TRB’s National Cooperative Highway Research Program (NCHRP) Report 651: LRFD Design and Construction of Shallow Foundations for Highway Bridge Structures explores recommended changes to Section 10 of the American Association of State Highway and Transportation Officials’ Load Resistance Factor Design Bridge Design Specifications for the strength limit state design of shallow foundations. Append...

TRB’s Transportation Research Record: Journal of the Transportation Research Board, No. 2116 includes 14 papers that explore instrumented rollers to assess construction quality, vibratory roller-measured soil stiffness and resilient modulus testing, automation of pavement sublayer moisture content determination, a stiffness-based assessment of pavement foundation materials, horizontal drains fo...