Thursday, March 15, 2012 | |||||
1:30 p.m. | Keynote Address Dr. Luis D. Alfaro, Vice President of Engineering, Panama Canal Authority |
Thursday, March 15 Concurrent Sessions | ||||
2:15 - 6:15 p.m. | ||||
RECENT RESEARCH AND DEVELOPMENT IN SMALL-DIAMETER DRILLING | ||||
ADSC/FWHA Study on Hollow Bar Soil Nails (HBSN) Tom Bird, Williams Form Engineering The use of Hollow Bar Soil Nails (HBSNs) is growing in the excavation support and retaining wall construction. The current state of practice for design bond strengths and load testing procedures is based on the current soil nail practice but varies depending on the installation contractor and product recommendations. The objectives of the study were (1) to determine if correlations exist between the available grout-to-ground bond stress of HBSNs as compared with traditional solid bar, drill, and grout soil nails; and (2) to establish recommendations for practical, standard ways of performing pullout tests on HBSNs. Comparisons between the pullout test results showed that the HBSNs generally developed larger bond strength values in granular soils than the SBSNs. For purposes of pullout and proof testing, three installation methods were evaluated. | ||||
Design for Slope Stabilization Using Micropiles J. Erik Loehr, Ph.D., University of Missouri This presentation will cover fundamental concepts and practical applications associated with using micropiles for slope stabilization. The presentation will include discussion of potential failure modes that must be considered as well as methods for prediction of resistance for micropiles when used to stabilize earth slopes. | ||||
Grout Confinement Effect on Strain Compatibility of Grade 150 Bars Thomas D. Richards, Jr. P.E., D.GE, Nicholson Construction Company Bar yields strengths used in design of compression piles have traditionally been limited to 80 ksi. This is based on reinforced concrete theory that concrete crushes at a strain of 0.003. In micropiles, the “concrete” is grout and is confined by the ground or casing. The ADSC-IAF funded research into the use of Grade 150 bars in compression with various levels of confinement. The results show that Grade 150 bars can be used in design provided the ground provides confinement stiffness of dense sand or better. | ||||
Micropile Design Installation and Performance for the Foothills Parkway Timothy C. Siegel, P.E., D.GE, Dan Brown and Associates, PC The presentation will discuss the design, installation and performance of the micropiles supporting a major portion of elevated roadway along the Foothills Parkway in the Smoky Mountain National Park in Tennessee. The project area was considered marginally stable during a previous geotechnical evaluation. The design team led by Bell Construction adopted micropiles for the bent foundations to minimize the disturbance to the existing vegetation and to ease the movement on the steep, marginally stable slopes. The micropile design was performed in accordance with LRFD. An interpretation of the micropile performance is made from strain gauge data collected during erection of the superstructure. | ||||
Tension Testing of Grouted Strand Anchorages Matt Niermann, Schnabel Foundation Company The results of full-scale load tests conducted on behalf of ADSC will be presented. The tests investigated whether the practice of filling trumpets and anchor caps with neat cement grout after lock-off affects the ability of the wedges to grip the strand when the load in the strand increases. The test results indicated that normal strength neat cement grout did not adversely affect the ability of the wedges to develop additional load carrying capacity, while very high strength grout did adversely affect performance. | ||||
Use of Percussive Drilling Performance Monitoring (PDPM) on the 281/1604 Interchange Joseph A Waxse, P.E., D.GE.,M.ASCE, Terracon The presentation will discuss the design and use of a system of pressure gauges and a laser distance measuring device combined with an automated data-logger installed on a pneumatic percussion rock drill (shot-hole rig). The system monitors rate of penetration and energy expended per foot of drilling into rock. The presentation will describe the PDPM data obtained and general comparisons with karst void detection, percent core recovery, RQD, Texas Cone and laboratory compressive strengths measured on rock cores from adjacent conventional borings. The general history of similar systems and the cost and benefits of use of the PDPM system will be explained. Use of a down-hole camera for karst feature exploration will also be discussed. | ||||
RECENT RESEARCH AND DEVELOPMENTS IN LARGE-DIAMETER DRILLING | ||||
ADSC Research Project Update: Rock Sockets in the Southeastern U.S. W. Robert Thompson III, P.E., D.GE, Dan Brown & Associates, PC This paper and presentation will present the results of load tests performed at two test sites (Nashville, Tennessee and Lawrenceville, Georgia) as part of an ongoing ADSC research effort. An overview of the tests will be presented, including the intentional testing of less than “ideal” rock conditions. The measured values of side and base resistance will be discussed. | ||||
Post-Grouted Drilled Shafts – FHWA’s Program Silas Nichols, P.E., Federal Highway Administration Presentation will provide an update to the FHWA’s on-going work in post grouted drilled shafts. The presentation will include a discussion on the status of current research to better understand improvement mechanisms for post grouting and the development of technical guidance. The presentation will also include a discussion on current FHWA guidance for use of post-grouting in drilled shaft construction. | ||||
Analysis of Inclined Load Tests in High Plasticity Clay Anand Puppala, Ph.D., Professor, University of Texas at Arlington Tom Witherspoon, Ph.D. , P.E., S&W Foundation Contractors Drilled shaft foundations are principally used to support many structures such as bridge piers, towers, buildings, transmission towers, and roadway cable barriers. This presentation focuses on the use of drilled shafts in the cable median barrier systems which play an important role in protecting people’s lives from cross-over collisions on highways. This research is supported by Texas Department of Transportation. | ||||
Crosshole Sonic Logging of Drilled Shafts William M. Camp III, P.E., D.GE,, S&ME, Inc. This presentation will include an overview of the CSL process and will summarize the results of 10 years of CSL experience in the Southeastern US. The distinction between anomalies, flaws and defects will be discussed and illustrated with case histories. Common findings and trends will also be discussed. | ||||
Thermal Integrity Method of Assessing Drilled Shafts Gray Mullins, Ph.D., University of South Florida The thermal integrity method of assessing drilled shafts makes use of the temperature generated by hydrating concrete to determine the presence or absence of cementitious materials. It is sensitive to concrete both inside and outside the reinforcing cage and as a result can determine concrete cover and cage alignment as well as the presence of anomalies. This paper describes the test method and case studies as examples. | ||||
SAFETY, QUALITY CONTROL AND PRODUCTIVITY | ||||
The Proper Installation Techniques and Testing of Drilled Shafts Bernie Hertlein, M.ASCE, AECOM Technical Services, Inc. Rick Marshall, Richard Goettle, Inc. Martin McDermott, Weeks Marine, Inc. This presentation is intended mainly for field personnel, including field and project engineers, field supervisors and foremen, and inspectors. The presenters, comprised of industry experts, will discuss proper installation techniques and testing methods pertaining to the construction of drilled shaft foundations. Moreover, the presenters will demonstrate how and where safety, quality, and productivity can be affected throughout the project. Specific topics of discussion include the drilling and cleaning of the borehole; stockpiling and handling of drill spoil; the handling, storage, fabrication, and installation of the steel reinforcement; the placement of concrete; and small-strain (e.g., crosshole sonic logging, integrity testing, etc.) and large-strain (i.e., O-cell testing and Statnamic testing) load testing of drilled shafts. There are several different techniques for evaluating the quality and integrity of drilled shafts, but each method has specific capabilities and limitations which, if ignored, can result in inconclusive or poor quality data that may be of little use, and can sometimes be misleading. Participation, discussion, and questions from all attendees is encouraged. | ||||
The Proper Installation Techniques and Testing of Anchors and Micropiles Jesús Gómez, Ph.D., P.E.,D.GE., Schnabel Engineering Dan Thome, P.E., Nicholson Construction Company As with the previous presentation on drilled shaft techniques, this one is also intended mainly for field personnel, including field and project engineers, field supervisors and foremen, and inspectors. The presenters, comprised of industry experts, will discuss proper installation techniques and testing methods pertaining to the construction and testing of ground anchors and micropile foundations. The presenters will demonstrate how and where safety, quality, and productivity can be affected throughout the project. Specific topics of discussion include the drilling and cleaning of the borehole for open/cased hole and hollow bar drilling; the storage, mixing, and placement of grout; the handling, storage, and installation of the reinforcement including concerns with corrosion protection; and the testing of ground anchors (solid and hollow bars, and strand anchors) and micropiles (solid bar and hollow bar), and the interpretation of results. Participation, discussion, and questions from all attendees is encouraged. |
Friday, March 16 Concurrent Sessions | ||||
7:30 - 4:30 p.m. | The Design-Build Experience Elizabeth M. Smith, PE, GE, Terracon Consultants, Inc. The presentation will provide a general overview of design build in transportation projects. Discussion will include the relationships and roles of the owner, engineer and contractors in a Design-Build project; the general procurement process; project delivery (how design gets done and how the construction is executed); execution of the work; changes during the design and construction process; and disputes during or following construction. | |||
LRFD: How Can It Advance the Deep Foundations Community? Jerry A. DiMaggio, PE, D.GE, M.ASCE, Jerry DiMaggio Consulting, LLC Much has been written and discussed about the Load Resistance Factor Design (LRFD) platform. The level of misunderstanding and degree of misapplication regarding its use and benefits is regretfully viral. This presentation will address the background of LRFD, misunderstandings and its benefits and application related to drilled deep foundations, (drilled shafts and micropiles) and cut earth retention systems. | ||||
Factors Affecting the Selection and Use of Drilled Shafts for Infrastructure Projects Dan Brown, Ph.D., P.E. D.GE., Dan Brown and Associates, PC This paper summarizes some of the critical components of drilled shaft design and construction that influence the selection of this foundation type for transportation structures. Recent advances in construction technology encourage the use of drilled shafts to overcome many of the challenges associated with modern infrastructure projects. Improvements in methods for performance verification measurements also impact the use of drilled shafts. Selected case histories are included. | ||||
Reliability of Drilled Shafts in Weak Rock J. Erik Loehr, Ph.D., University of Missouri A comprehensive load test program was recently completed for the Missouri Department of Transportation to assess the reliability of drilled shafts used for bridge foundations. In this presentation, results of the load test program, which included 25 tests on two sites, will be presented. Implications from these results will also be provided, with particular focus on implications for contractors and designers. | ||||
Utah Light Rail Airport TRAX Link Lance Rasband, Malcolm Drilling Co., Inc. Utah Transit Authority (UTA) approached Malcolm Drillling for help during the design process of the North Temple Viaduct replacement. Their original design called for eight each 12’ diameter pier shafts along with eight each 10’ diameter abutment shafts. Upon working with the owner and implementing a 6.56’ diameter load test program, we were able to change the design to eight each 9’ diameter shafts and eight each 6.56’ diameter abutment shafts. Working together during the design stage, allowed the owner to make significant savings on the project. | ||||
The Evolution of Small Hole Drilling Methods for Geotechnical Construction Processes Donald A. Bruce, Ph.D., D.GE., C.En, Geosystems, L.P. The evolution of drilling methods for rock and overburden drilling is described via developments over the last 40 years. These methods have application in anchor, nail, micropile and grouting projects. | ||||
Design and Applications for Anchored Earth Retention Systems John R. Wolosick, P.E., D.GE., Hayward Baker Inc. Anchored earth retention (AER) systems are primarily used for projects where cuts are excavated to provide grade separation. These systems have supplanted other traditional earth retention installations such as cantilevered concrete and masonry retaining walls over the last several decades. Tieback walls and soil nailing are the most common AER systems in use today. The increased use of these newer AER systems is due to a reduced cost as compared to the older earth retention designs, particularly for tall walls. The routine use of AER has been made possible through the application of modern computational software and hardware that was not available in the past. User-friendly and menu-driven programs are available for the experienced engineer to design these installations. The design and applications for AER are discussed in this paper. | ||||
Micropiles: State of the Practice in Design and Construction Allen Cadden, P.E., D.GE., Schnabel Engineering This session will review some of the basics of micropile terminology, design, construction and quality control. Key challenges with design and construction unique to micropiles will be emphasized. Case histories will be used to demonstrate implementation of these systems to solve challenging problems. | ||||
Proper Setup and Understanding of Testing of Ground Anchors and Micropiles Thomas D. Richards, Jr. P.E., D.GE, Nicholson Construction Company Many pile and anchor tests overlook important setup details. Also, several common analysis misunderstandings frequently occur. This presentation will focus on these details and misunderstanding. | ||||
Anchored Earth Retention – Planning & Execution Frederick (Rick) W. Slack, P.E, Richard Goettle, Inc. As with any construction project, planning and preparation of an anchored earth retention project before moving onto the site will go a long way to creating a successful project. Typically, this involves the site logistics and work activities. However, it can also involve anticipating questions and concerns the owner and reviewing engineers may have, both in general and for the specific project. This presentation will highlight some of the common questions and concerns the reviewers may have; some of the details that should be addressed early in the project; and how these items apply to a deep excavation earth retention system in downtown Cincinnati, Ohio. |