The program computes deflection, bending moment, shear force and soil response. Where the shaft is drilled some depth into sound rock, a combination of. Few existing published analysis methods are still in their early stage of development due to meager lateral load tests data for verification. They can range from 2 to 30 feet in diameter and can be over 300 feet in length. Drilled shafts drilled shafts caissons or drilled piers are typically high axial and lateral load deep foundation systems. Construction procedures and lrfd design methods fhwads was published in 2010 and presented updatedmethods for determining the geotechnical axial capacity of drilled shafts in.
Lpile analysis of piles and drilled shafts under lateral. These updates have since been incorporated into the aashto lrfd bridge design specifications lrfd effective with the7. Do not define the top of the drilled shaft in the normal manner a set distance below finished grade. Moments induced in this manner are not typically present in beam on nonlinear winkler. Allpile is a windowsbased analysis program that handles virtually all types of piles, including steel pipes, hpiles, precast concrete piles, augercast piles, drilled shafts, timber piles, jetted piles, tapered piles, piers with bell, micropiles minipiles, uplift anchors, uplift plate, and shallow foundations. Drilled shafts, also referred to as drilled piers, caissons or bored piles, are deep foundation solutions used to support structures with large axial and lateral loads by excavating cylindrical shafts into the ground and filling them with concrete. Design of straight shaft drilled pier bearing into rock bridgesmith structural 27 mar 19 01. This book is the first to present and summarize the latest. The main loads applied on the drilled shafts are axial compressive or uplift loads as well as lateral loads with accompanying moments. If soilsupported shafts are to be used, they must be approved by the soils design section and obs chief structural engineer. Designation rqd of rock and igm are the three most common. Drilled shafts installed in lakes or rivers require use of a casing placed from above the water surface to a minimum embedment into the river or lake bottom.
Settlement resistance factors for tz method for drilled shafts in rock. For the purposes of the design guide, the term rock is intended to refer to the geological deposits common to illinois including limestone, dolomite, sandstone, as well as hard shale deposits with an unconfined compressive strength q. Download geotechnical engineering software shaft 2017 developed by ensoft. Like the shear strength of a rock joint, the shaft resistance of a pile in rock is a frictional.
Design and construction of drilled piers reported by aci committee 336 aci 336. When shafts undergo loading in the field, transfer of axial load from shaft to soilrock takes place at the shaftsoilrock interface along the shaft and in the toe fig. Design based on end bearing alone should be considered when sound bedrock underlies low strength overburden materials, including highly weathered rock. Drilled shafts are widely used to transfer heavy structural loads both axial and lateral through the overburden soil to the underlying rock mass. Design guide axial capacity of drilled shafts in rock. Although there exist several analysis and design methods especially for rocksocketed drilled shafts under lateral. Although numerous research efforts on rock socket drilled shafts under vertical loads have been carried out, similar research efforts on rock socketed shafts under lateral loads have been lacking. Factor design of drilled shafts using historical field test data 20. Settlement resistance factors to be applied to side resistance for shaft segments through rock shall be determined from figure 751. Proposed point bearing load transfer function in jointed. Design of straight shaft drilled pier bearing into rock. Rock socketed drilled shafts, lateral loads, pressuremeter, py method, anisotropy, intermediate geomaterials.
Drilled shafts design and construction slide 3 of 51 concrete mix design considerations massdot lrfd design manual 2009 section 3. Criteria for the design of axially loaded drilled shafts. Drilled shaft bridge foundation design parameters and. The point bearing behavior of rocksocketed drilled shafts under axial loading is investigated by numerical analysis and a load transfer approach qw. Because of the shear transfer at a distance, moments develop taken as the product of shear stress. Challenges faced by foundation designers when considering rocksocketed drilled shafts include. Lateral geotechnical resistance of soil and rock stratum, for single shafts and shaft groups geotechnical axial resistance compression and uplift. Authors zhang, lianyang, 1964downloadfull printable version 6. Up until now, you needed one program for axial capacity, another for lateral load analysis and yet a third program for reinforcement design. Based on the findings of this study, a complete solution for the design of drilled shafts socket ed in anisotropic rock or intermediate geomaterials under lateral loads is provided. The construction method to install the drilled shaft foundations is expected to utilize temporary casing and drilling slurry water. This project was aimed at evaluating and developing design methods for laterally loaded drilled shafts socketed in rock. Interaction between soils and obs in drilled shaft design. A numerical analysis using the distinct element method dem is carried out to investigate the effects of pile diameter and the elastic modulus, discontinuity spacing and the inclination of rock mass on the point bearing behavior.
Drilled shafts directly support bridge substructure components, light towers, sign structures, and other transportation structures. Five lateral load tests on rock socketed drilled shafts with full range of instrumentation were conducted in ohio. Where end bearing in rock is used as part of the axial compressive resistance in the design, the contribution of skin friction that occurs once the shear deformation along the. Analysis and design of drilled shafts socketed into rock. Lpile is a specialpurpose and internationally recognized computer program based on rational procedures for analyzing a pile under lateral loading using the py method. Carter and others published analysis and design of drilled shafts socketed into rock find, read and cite all the research you need on researchgate. Construction practices and defects in drilled shafts. Ummm, the program driven is not for the analysis and design of drilled shafts. The updated methods and equations are described below and are also reflected in a design spreadsheet available at. The use of polymer drilling fluid does not appear to have any detrimental effect on the shaft. Practices for design of bored piles drilled shafts. Pdf analysis and design of drilled shafts socketed into rock.
Smallerdiameter piers have been used in noncollapsing soils. Minimum embedment depth for drilled shafts geotechgal geotechnical op 18 may 05 17. Drilled shafts in rock analysis and design pdf free download. The minimum clearance between reinforcing bars shall be 17. The last three decades have seen sustained research and development efforts around the world to improve the technology of drilled shafts in rock. Although much has been learned about the analysis and design of drilled shafts in rock, all the major findings are published in the form of reports and articles in technical journals and conference proceedings. To download click on link in the links table below description. In the paper the analysis of the interaction of drilled shafts with soft and middle strength rock masses is considered. Analysis and design of axially loaded drilled shafts. A cylindrical shaft is excavated, reinforcing steel is placed in the excavation and concrete is placed to form the shaft. This approach was extended to rocksocketed shafts by zhang et al. Verification and calibration of the design methods for. An investigation of load and resistance factor design of drilled. Drilled shafts 1 mullins drilled shafts introduction drilled shafts are deep, cylindrical, castinplace concrete foundations poured in and formed by a bored i.
Analysis and design of axially loaded piles in rock. An example application was presented to guide users in utilizing the simplified approach. The analysis is based on results of three dimensional numerical modeling of. Analysis and design of axially loaded piles in rock sciencedirect. Key words drilled shaft, drilled shaft capacity, axial loads, skin friction, end bearing, drilled shafts design models, dilation, compressibility. The main loads applied on the drilled shafts are axial compressive or uplift loads. Abttroct a method is presented for the design of drilled shafts that are employed as a retaining wall. Analysis of laterally loaded drilled shafts in rock yang ke, university of akron may 2006 drilled shafts socketed into rock are widely used as foundations for bridges and other important structures. The term drilled shaft is synonymous with castinsitu piles, bored piles. Drilled shafts in rock are widely used as foundations of heavy structures such as highway bridges and tall buildings. The casing will first be sealed into competent rock and then the shaft will be drilled out to the design depth. It is for the analysis and design of driven pile foundations hence the name driven.
Minimum embedment depth for drilled shafts foundation. Improved design of drilled shafts in rockshafts in rock. Although much has been learned on the analysis and design of drilled shafts in rock, all the major findings are reported in the form of reports and articles published in technical journals and conference proceedings. Reese, describes the results of axial load tests of instrumented drilled shafts having varying geometry and differing methods of installation and presents a tentative design. Get your kindle here, or download a free kindle reading app. Construction and design methods september, 2018 geotechnical engineering circular no. Shaft is a computer program used to evaluate the axial capacity and the shortterm, loadsettlement curves of drilled shafts or bored piles in various types of soils. The design methods for drilled shafts presented in this chapter are largely. Click to see full description drilled shafts in rock are widely used as foundations of heavy structures such as.
Design for lateral loading the national academies press. Effects of construction on performance and design criteria fhwa conf. Evaluation of lateral response of drilled shafts in rock. Drilled shaft in rock analysis and design preface drilled shafts are widely used to transfer heavy structural loads both axial and lateral through the overburden soil to the underlying rock mass. Although much has been learned about the analysis and design of drilled shafts in rock, all the major findings are published in the form of reports and articles in. Drilled shafts in rock drilled shafts in rock analysis and designlianyang zhang icf consulting, lexington, ma, usa. Structures obs typically requires that drilled shafts for bridge support be socketed into rock. Shaft can accommodate any combination of soil and rock layers in a layered profile. Drilled shaft in rock analysis and design damasgate.
Drilled shafts that are embedded in soft rocks develop 48 their axial. Download drilled shafts in rock are widely used as foundations of heavy structures such as highway bridges and tall buildings. It is important to consider the effect of discontinuities when designing drilled shafts in rock. Detailed instrumentation included the use of vibrating wire strain gages, inclinometers, dial gages, and load. Pdf drilled shafts in rock analysis and design download. Rocksocketed drilled shafts are also used to stabilize a landslide.
Shaft study of drilled shafts under axial loading software. Drilled pier bored pile software soilstructure software. Analysis and design of axially loaded drilled shafts socketed into rock. Drilled shafts are typically designed and constructed to support axial forces through a. Improved design of drilled shafts in rock improved design of drilled shafts in rockshafts in rock by. Toward these goals, existing analysis methods for both capacity estimate and loaddeflection predictions of drilled shafts supporting sound barrier walls, signs, and signals and typical soil and rock formations in colorado are presented in a comprehensive manner. Lpile solves the differential equation for a beamcolumn using a finite difference approach.