Search Documents

By Paul Summers, Kevin Richardson, Willem (Billy) Villet, Paul J. Sabatini, Edward C. Clukey

"Between 2008 and 2009, more than 6,000, 23-m long deep mixing method (DMM) elements were constructed to support 124 concrete mats comprising the foundations for the process trains for an LNG facility. The Owner requested first-of-its-kind analyses and assessments to confirm the quality and reliability of the DMM foundation. This paper provides information on these assessments and the procedures used to ultimately conclude that a fit-for-purpose foundation system was constructed.During early phases of construction, several DMM test cores revealed nodules of unmixed clay in upper core samples. A comprehensive review of available DMM core information was undertaken. It was concluded that the amount of coring being conducted as part of the contractor’s QA/QC program should be increased to achieve a foundation system with the required level of reliability.Three-dimensional finite element analyses were completed considering various distributions of defects in the DMM elements and the effects of potential downdrag on DMM elements. Calculated mat settlements and mat stresses were compared to cases without defects in the DMM elements. Various distributions of loaded and unloaded mat areas and number and position (both in the subsurface and laterally) of defects were considered. Four (of the 124) mats were identified as potentially “at-risk”. The settlement performance of these mats is currently being monitored and, to date, performance has been acceptable.IntroductionThe foundation support system for the process train at a major LNG facility comprises more than 6,000, 23-m long DMM elements. The general subsurface stratigraphy at the project site comprises (from the ground surface): (i) up to 8 m of fill sand initially placed underwater building to a stable construction platform; (ii) up to 12 m of soft organic clay (Unit II clay); and (iii) clayey sand and sand layers becoming progressively denser with depth (Unit III sands). Each DMM element comprised two secant 1.5-m diameter DMM columns. DMM elements were typically arranged as cells enclosing one, two, or three DMM elements."

Jan 1, 2017

By George Machan

Bitumen coatings have been successfully used to significantly reduce downdrag on piles. Thicker coatings of "soft" bitumens can accommodate downdrag so well that very little downdrag load is transferred to the pile. Many of the case histories describe better than 80 percent downdrag load reduction. Bitumen coatings have been used on several projects in Oregon. On the Mocks Bottom Bridge project (see Reference 1), experimentation and instrumentation confirmed the viability of bitumen coatings and provided insights for design and construction. Subsequent bridge projects have used this information and have raised issues to be resolved.

Jan 1, 1989

By George M. Filz

Restrained basement walls and unrestrained but massive concrete walls on rock foundations experience very small movements in response to lateral earth pressures. Such walls are often designed using at-rest earth pressures without consideration of either compaction-induced lateral pressures or vertical shear forces resulting from compression of the backfill in response to self-weight. Compaction-induced lateral earth pressures can be detrimental to the integrity and stability of retaining walls. For example, the lock walls at Eisenhower and Snell Locks on the Saint Lawrence Seaway near Massena, New York, were damaged by compaction-induced lateral earth pressures, and an extensive rehabilitation program was necessary to ensure safety of the locks. Vertical shear forces, on the other hand, can be beneficial to stability because the downwards-directed vertical force tends to counteract the overturning moment from lateral earth pressures. The contribution of vertical shear forces is not included in most modern analyses of non-moving walls, but Terzaghi used this effect in his design of a high concrete retaining wall at Fifteen Mile Falls Dam. The lock walls at Eibach Lock on the Main-Donau Canal in Germany were instrumented for both lateral and vertical stresses applied by the backfill to the wall, and the resulting measurements show that vertical shear forces from the backfill were significant and persistent over the multi-year period that the wall was monitored. Other data from pilot-scale retaining walls confirm the existence of both compaction-induced lateral earth pressures and vertical shear forces. These forces should be considered in design of non-moving walls.

Jan 1, 2003

By Helen Ahnberg

The scope of the present paper is limited to report the experimental evidence and not for describing the analytical assumptions. However, the idea behind the experimental program is that the deterioration may be caused by the leaching of Ca from the treated soil to surrounding soil or water driven by the difference in the Ca ion concentration. As a consequence of Ca leaching, it may be natural to expect the expansion of micro void space within the treated soil. In a saturated condition, the water inflow into the treated soil may accompany the leaching phenomenon. We measured the water content within the treated soil. But there is not much difference in water content within the soil.

Feb 10, 2003

By Sebastian Fischer, Rolf Katzenbach, Steffen Leppla

"The risk management in the case of liquefaction is one of the most serious and also difficult issues in geotechnical engineering because failure caused by liquefaction is always a sudden failure without ahead indication. For that reason ground improvement technologies for the prevention of liquefaction are necessary. The paper explains the responsible and effective risk management. Methods for the risk management and stabilizing the soil sustainably are described in detail.1. INTRODUCTIONDue to population growing more and more settlement area is needed, which is often including improper regions (e.g. mountain and coast regions) with raised risk of various kinds of disasters. But also in densely populated areas the risk of disasters like landslides can occur. One reason for the raising of risk in densely populated regions can be the opencast mining for raw material production. An essential element of the opencast mining is the loose deposition of the removed overburden, the so-called “overburden dump”. When an opencast mining is running out of the raw material, an opencast hollow remains in landscape. The slope areas of these hollows mostly consist of loose bedded material of the overburden dump. Due to the end of groundwater conservation these loose bedded slope areas are flooded. In consequence the slopes are in extreme danger of becoming liquefied. The result of a liquefaction in these slopes will unavoidably be a slope slide. Such a slope slide can extend up to several hundred meters into the landscape and can move several million cubic meters of material. An upsetting example for such a landslide is the slope failure in the German city of Nachterstedt on July, 18th 2009, which made necessitate remedial measures and also prevention works for the further utilisation of the region. The phenomena of liquefaction is not limited of slopes in series of opencast mining. Especially in regions with a highly appearance of earthquakes the phenomena of liquefaction is well known.2. RISK MANAGEMENTAn essential part for the stability assessment of slope systems is the investigation of sensitivity against liquefaction. In the case of given sensitivity against liquefaction there is no calculation method according to soil mechanics to determine the factor of safety against slope failure. Just for the case that sensitivity against liquefaction is not met, a comparison of the load (effect) E and the resistance R which is the traditional verification of stability against slope failure, can be calculated (Figure 1)."

Jan 1, 2015

By Douglas G. Baker, Jason K. Braund-Read, Megan R. Sheffer

"Mica Dam, owned by British Columbia Hydro, is an 820 ft high earthfill embankment dam that was completed in 1973. The dam consists of a thin central impervious till core supported by upstream and downstream compacted sand, gravel and cobble shell zones, founded on bedrock and valley bottom alluvium deposits. In 2012, a project was started to install new piezometric instrumentation within the dam’s foundation and downstream shell zone.Deep drilling in large embankment dams is very difficult and requires careful planning to select a methodology capable of reaching the target locations, while ensuring that no damage is done to the surrounding dam fill zones. At Mica Dam, the drilling could only be carried out from the Dam Crest and drillholes had to be carefully oriented to avoid intersecting any existing dam instrumentation. The drilling work therefore required angled drillholes, at depths of up to 855 ft, through heavily compacted sands, gravels and cobbles, and to significant depths below the standing water table.During the planning stages for the Project, in early 2013, the preferred drilling method was selected and a drilling contractor was engaged for the drilling work. Critical dam safety concerns were identified and addressed during the design stage of the Project with the drilling contractor, so that risk mitigation measures and response plans could be effectively developed.This paper explains how background information and prior drilling experience influenced the final design and implementation of the drilling techniques used in 2013 to successfully drill the deep holes and carry out the piezometer installations in Mica Dam. Drilling procedures, instrumentation design and installation methods, as well as risk mitigation measures, are discussed."

Jan 1, 2017

By Martina Balic

Dynamic properties of the drilled shaft foundations supporting Doremus Avenue Bridge were determined by forced vibration testing. The main objectives of the substructure testing at Doremus Avenue Bridge were: (1) site evaluation with respect to the dynamic soil properties, and, (2) shaft evaluation for the purpose of definition of their dynamic stiffness. The site characterization entailed crosshole testing for the purpose of evaluation of the shear modulus profile. The drilled shaft impedance evaluation was done through forced excitation using an electromagnetic shaker. The responses of the tested shaft, as well as the response of adjacent shafts, were measured for the purpose of evaluation of the shaft interaction. To gain a better insight into the shaft dynamics, one of the shafts was instrumented with five triaxial geophones distributed along the full length of the shaft. The scope and results of the site characterization, shaft impedance and shaft interaction evaluation are presented.

Jan 1, 2004

By Bastian Hoffmann, Christian Moormann

The paper presents results of an experimental study on the axial load bearing behavior of vibratory driven full displacement piles in comparison with impact driven and cyclic quasi-static installed piles in dense sand. The test setup and the measurement devices used to this end are explained. Subsequently, the results of the axial loading like load settlement curves are shown and the impact of the installation method is interpreted. The results presented in this work are mainly based on three installation methods: test series one investigates axial behavior of vibratory driven piles, test series two describe the same cyclic pile installation process but without dynamic influence wherein a special test setup developed to install the piles cyclic quasi-static in the soil was used. A third test series carried out using the conventional impact pile driving method served the purpose of not only comparing the results against vibratory driving, but also aided in isolating the effects of dynamics inherent to the vibratory driving process.

May 1, 2022

By Walter G. Brusey

This paper describes a comprehensive pile test program conducted at John F. Kennedy International Airport (JFKIA) to evaluate pile types and design capacities ranging from 890 to 4450 KN (100 to 500 tons). Driven cased piles and drilled shafts, both standard construction and post-grouted after installation, were tested with platform loads extending to 8900 KN (1,000 tons). Alternate load test procedures were developed, extensive structural integrity testing and dynamic load tests were performed on selected shafts. A brief update is provided covering the application of results of the test program to pile selection for support of major structures incorporated in the on going redevelopment of JFKIA.

Jan 1, 2000

By Ray Zelinski

Caltrans sponsored a research project in 1992 which incorporated proprietary and generic pile types. The piles were subjected to axial tensile/compressive loads in deep, soft soils. Descriptions of various pile types and systems, scenarios leading to the proposal to test the systems, and load test results were/will be provided by other presenters at this seminar. Therefore, this paper will focus on the issues surrounding use of test results and proprietary pile systems on Caltrans construction projects. The primary issues facing Caltrans during implementation are as follows: 1) producing pile cap designs for a range of pile types and loads; 2) providing construction specifications which allow fair competition among the system vendors, yet assure design and ultimate capacities; 3) Develop quality control standards for pile system materials and installation techniques which guarantee pile durability for static and dynamic loads; and 4) assure that foundations have adequate lateral capacity.

Jan 1, 1993

By Brian W. Wilson

A case study is presented that describes the design and implementation of a combined blast densification and deep dynamic compaction program which was undertaken to improve the foundation soils for a proposed tailings dam raise in Ontario, Canada. Based on the results of the geotechnical investigation it was determined that the foundation of the dam would be situated on tailings of both variable thickness and density, much of which would be susceptible to liquefaction under the design earthquake for the region and type of facility. Blast densification trials were completed by the owner and the results of these made available to prospective tenderers in response to a call for a fixed price contract for the design and implementation of a densification program for approximately 800,000 m3 of foundation tailings. The variation in tailings gradation and the impacts of such on the ground improvement program are discussed, as are details of both the additional blast densification field trials completed by the contractor, and the selected blast pattern and explosive charging used for production blasting. The applicability of the various ground improvement techniques to the actual conditions encountered, and the results obtained are also discussed.

Jan 1, 2010

By K. J. Yang

Based on investigations and model tests combined with pile foundation on Code compilation of drydocks, we present this report to give informations against uplift pressure of piles beneath floor of drydock. In a same kind of soil, we have got comparative tests results with single pile and pile group, and the latter was performed at different spacings, different embedded depths and different number of piles in the group. Having analyzed through the results, there are some new understandings of regularity about failure mechanism and uplifting capacity of single pile and pile group, as well as optimum embedded depth of pile foundation. The results of research approach to measured values of full-scale and model tests at home and abroad, it has been placed into the Design Code of Drydock in China (1985), and can give a reference to design of pile foundation at sea and on land under uplift loading.

Jan 1, 2010

By Ahmed Elmekati, Frederick C. Rhyner, Steven R. Lowe

"The current phase of the Pacific Park development (formerly, Atlantic Yards) in Brooklyn involves constructing buildings on a platform over an existing LIRR rail yard. To preserve the maximum amount of space in the already congested yard and protect the yard which remains in service during construction, high capacity foundations are being designed well above previous capacities in the area. In addition to spread footings and small mats, various diameters of drilled piles are being used at design capacities ranging up to 600 tons. The piles are generally grouted at low pressure, up to about 50 psi. Load tests for various drilled elements, including piles, tiedowns and soil anchors, have confirmed allowable side resistance (bond) stresses in dense sand ranging from 20 to 30 psi. Testing with different rigs and operators has shown that down-the-hole hammers are feasible, but the installation techniques, types of equipment and size of the pile make a significant difference. The results show that more cost-effective foundations are possible when ample testing confirms expectations.I INTRODUCTIONThe Long Island Rail Road has operated a mainline on Atlantic Avenue since the 1800s, with a terminal at the intersection of Atlantic and Flatbush Avenues. In the early 1900s, the mainline was reconstructed in a cut and cover tunnel section. The LIRR’s Atlantic Yard was constructed circa 1908 to service the terminal. It was depressed about 25 feet below street grade to coincide with the LIRR’s mainline tunnel under Atlantic Avenue. Record drawings indicate that the gravity retaining walls lining the perimeter of the yard and other ancillary structures had been designed for an allowable bearing pressure of five tons per square foot (tsf). Perhaps by coincidence, the mat foundation for the tower of the Williamsburg Savings Bank was also designed for five tsf in 1929.Figure 1 shows a typical geologic section through the site. The geology and subsurface conditions in this part of Brooklyn consist of fill generally five to 20 feet deep underlain by dense to very dense sand and gravel; in places, with numerous cobbles and boulders which make pile installation challenging. The sand strata that are on the order of 150 to 200 feet thick were laid down by glaciers during the last ice age and have been heavily precompressed. The sand strata are underlain in places by remnants of the Cretaceous-era Raritan Clay formation and Fordham Gneiss bedrock. Because of this, the sand strata generally provide excellent support for shallow foundations and the allowable bearing of five tons per square foot is usually easily justified."

Jan 1, 2016

By Kevin Cunningham

"Litigation resulting from neighboring structures with settlement and/or lateral movement or improper pile design and faulty soils engineering analysis, are a multi-faceted opportunity for law firms. These types of claim scenarios are an attorney’s dream, and can obliterate a Deep Foundation Contractors profit and more importantly, can be avoided with a progressive approach to risk management in design and project management.The following (4) case studies will be examined and dissected to discern certain lessons learned for risk management solutions to avoid these deep foundation related challenges in the future.1) Pipe Flotation – Soil Conditions Not Anticipated in Specifications or Contract2) Easement Encroachment – Easement Dimensions Not Recognized Until Completion of Project3) Subjacent Lateral Support – Neighboring Structure Wooden Pile Unprotected Causing Structure to Settle4) Improper Pile Placement - Construction & Design Caused Retail Store to SettleSpecific Deep Foundation project challenges involving: buoyancy calculations regarding subsurface soil characteristics, design factors taking existing subsurface sewer line easements into account, structural instability as result of excavation causing exposure/heavy rainfall to existing wooden piles supporting adjoining building and improper pile location resulting from faulty pile design will be described with risk management recommendations to avoid these challenges in the future.From the very start of construction on any project deep foundation and excavating work poses numerous engineering and technical challenges for developers, contractors and engineers. Dealing with changing or hidden conditions is one of the most difficult challenges facing any contractor or engineer on a project. Relying on incomplete or inaccurate engineering reports is another common problem. Other challenges include dealing with technical errors or oversights that are deeply embedded in the project specifications or bid process.No matter what is the origin of the problem or how it manifests, deep foundation contractors, design professionals and engineers should be ever-mindful of good risk management practices that can prevent serious disputes that can result in costly litigation."

Jan 1, 2015

By G. Stuart Littlejohn

In spite of recent concerns in certain European countries, I believe that silicate-ester grouts will continue to be employed in practice, unless more cost-effective inorganic grouts are developed for the treatment of fine sands. It is also noteworthy that over the past 40 years, there has been a record of good experience where silicate-ester grouts have been used in ground improvement. Nevertheless, there is now a need via the European Standard EN 12715 (2000) "to assess the environmental impact, particularly the toxicity of the grout and grout components, and their effect on ground and drinking water should be considered before grouting." "When testing the grouting material for environmental impact, the following aspects should be considered: ? Whether during processing, transport or grouting, substance can be generated or released which could be hazardous to the environment or the grouting crew; ? Whether noxious substances can spread upon mixing with ground water; ? Whether reaction products can be produced or released which influence the water quality; ? The type of particles eroded from hardened grout; ? Chemical reactions between hardened grout and the ground water."

Feb 10, 2003

By Steve Davidow, Nick Salisbury

"The Sunrise Powerlink project received numerous industry awards for excellence. The DFI C. William Bermingham Innovation Award recognized the innovative use of prefabricated steel micropile caps to increase safety, accelerate project schedule and minimize the project carbon footprint. DFI’s Outstanding Project Award (OPA) and World Cup of Micropiles Challenge Award honored the project as a whole and its positive outcome and industry example. Sunrise Powerlink involved construction of San Diego Gas and Electric’s (SDG&E’s) new 117 mile (188 km) 500/230 kilovolt transmission line from Imperial County to San Diego County, Calif. The alignment traversed a wide variety of geotechnical conditions, including desert, mountain and marine environments, and many of the 421 lattice tower structures used to carry the transmission lines were located in remote, rugged or environmentally-sensitive terrain.Micropiles were introduced as a solution to foundation construction in these challenging areas, which ultimately involved the design and application of Crux Subsurface Inc.’s patented steel micropile cap at 234 tower locations. This was the inaugural application of the technology, and a significant component to ensuring a successful project outcome. Foundation ChallengesThe alignment crossed a number of protected environments, including National Forest land, critical habitat for bald eagles and Peninsular big horn sheep, and numerous private properties. As a result of the remote, rugged terrain, it was initially determined that 75 lattice tower locations would not permit road construction access and would require helicopter-only construction techniques. A strict in-service date combined with long permitting lead times eventually increased this number to 234 sites. Preconstruction access constraints prohibited site-specific geotechnical sampling, so initial foundation designs were completed using only available seismic geophysical surveying and preliminary mapping data. The combination of these challenges required a foundation alternative that could accommodate variable subsurface conditions, required a minimal environmental footprint for installation, and featured lightweight materials and equipment that could be transported by helicopter."

Jan 1, 2014

By Jennifer Peirce Brandt

Project documents and the United States Army Corps of Engineers? permit for construction of the Stemmers Run Relief Wastewater Force Main across the Back River in Baltimore County, Maryland specified a minimal width, steel sheet pile cofferdam and a 12 feet wide, pile supported, timber decked, causeway trestle ? both approximately 1700 feet in length. Due to the impractical width of the causeway, the contractor desired to combine the cofferdam and the causeway structures in order to minimize wetland disturbance and maximize access for construction equipment. The resulting support structure was a steel sheet pile cofferdam, approximately 17 feet wide, internally braced, and capped with transverse timber deck mats to serve as the access and work trestle for the trench excavation, pipe bent construction, and trench backfill. Construction of this cofferdam/causeway progressed from the north shoreline toward the middle of the river. Then, working back toward the north shoreline, the contractor excavated, installed the 54 inch diameter pipe and H-pile support bents, and backfilled the trench in increments of approximately 60 linear feet. Excavation spoils from one section were used to backfill the preceding section. As the pipe installation progressed toward the north shore, the steel sheet piling and timber deck were removed. As sufficient sheet piling and deck mats were removed, the contractor began the process anew from the opposite shoreline using the reclaimed materials. The project was complicated by the presence of deep, very soft, weight of hammer, silts and organic clays and an unbalanced, hydrostatic head of 20.5 feet. In addition, concurrent pile driving, excavating, and backfilling in successive cofferdam sections required the use of heavy, long reach, hydraulic backhoes, and a 200 ton capacity crawler crane which controlled the design of the timber causeway deck and its supporting sheet piles.

Jan 1, 2008

By Masakazu Takano, Koji Suzuki, Naotoshi Shinkawa

"Cement deep mixing (CDM) method successfully applied to a marine construction project in northern Vietnam is reported. The method is classified as wet method, in which cement slurry is injected into the ground. Thickness of clayey deposit subjected to improvement is from 20 m to 28 m, and the total volume of CDM improvement exceeds 460,000 m3. This is the first massive application of CDM method in the region. Three CDM barges, each equipped with four mixing shafts, were brought to the site in order to finish CDM work within a period of seven months. Cement content used in the work was 180 kg/m3 and water-cement ratio of slurry was 100%. Unconfined compression strength of stabilized soil was 1,200 kPa to 1,600 kPa in average with coefficient of variation from 0.3 to 0.4. Statistics analysis of the strength with these values gave percentage of lower strength less than 10%. Trial use of needle penetration test performed to study strength profile of a CDM column is also reported.INTRODUCTIONThe site of Lack Huyen Port Infrastructure Construction Project is located in the sea adjacent to Cat Hai Island, offshore Hai Phong city which is around 100 km east of Hanoi, the capital of Vietnam. Left side of Fig. 1 shows the location of the site. The project contains development of container terminal, dredging of waterway, construction of sand protection dyke to prevent waterway from being buried, and bridge construction to connect the island to the mainland.Joint venture of Penta Ocean Construction and Toa Corporation was awarded Package 6 of the project, in which reclamation of container terminal area, retaining wall construction and terminal road construction were included. Plan of the site is presented in right side of Fig. 1. The site work has been started in June 2013 and is scheduled to finish within 4 years."

Jan 1, 2015

By M. Hesham El Naggar, Tony Sangiuliano, Alper Turan

"Bridge abutments supported on pile foundations are often constructed over weak and compressible soils. The consolidation settlements induced by the embankment loads are known to result in downdrag and lateral forces on the piles supporting the bridge abutments. The performance of a pile group including inclined piles embedded in consolidating soils was investigated numerically considering surcharge loads from approach embankment construction. A two-dimensional numerical model was constructed using commercial finite element software PLAXIS and calibrated against field measurements of the abutment movements observed on Brookdale Avenue Underpass Structure located on the Macdonald-Cartier Freeway in Ontario between Cornwall and the Quebec border. The soft soil model (SSM) was used to simulate the constitutive behavior of the compressible soil deposit. The SSM model parameters were determined based on the laboratory tests. Subsequently, time dependant development of downdrag effects was comparatively evaluated for vertical and inclined single piles as well as a pile group that included both vertical and inclined piles.Results showed that drag loads increased with the consolidation time. However, majority of accumulation of drag loads took place within first 120 days after installation of piles. The results also indicated that the shear forces and bending moments are controlled by the lateral spreading of foundation soil and their accumulation is proportional to consolidation time. The large axial strains caused by large downdrag forces are considered to have yielded the piles and this is a possible reason for unusual abutment movements. The results presented in this study are considered to be of interest to researchers and practitioners.1. IntroductionDeep foundation units are widely used for supporting bridge piers and abutments, where weaker surficial soils preclude shallow foundations. Particularly in Ontario, semi-integral and integral abutment bridges are typically supported on end-bearing steel driven piles. The construction of approach embankments over weaker, compressible soils results in significant vertical and lateral soil movements, which induce additional loads on piles supporting the abutments. In order to minimize such effects, preloading and surcharging are commonly employed approaches to avoid unanticipated settlements prior to the installation of piles. Other alternatives such as aggregate pier supported approach embankment are also being studied as the schedule restrictions imposed by preloading and surcharging becomes cost prohibitive (Turan et al. 2012)."

Jan 1, 2015

By Travis A. Shoemaker, Mitchell S. Youmans, Nancy T. Chin, Michael S. Senior

A geologic assessment and stability analysis of the right abutment of Boundary Hydroelectric Dam in Pend Oreille County, Washington was completed in May 2017. The stability analyses identified a potential failure plane of a rock block that supports a bridge abutment, and weight restrictions were established to reduce the bridge loads. To restore full use of the bridge, a long-term stabilization solution was designed. A two-phased construction approach was implemented to reduce risk: (1) cable lashing and wire mesh and (2) 24 permanent post-tensioned tiebacks. The tiebacks were located and sequenced based on stabilization effect and site access to incrementally ease the bridge loading restrictions throughout construction. Due to weight restrictions and site tolerances, all work was performed with rope access construction methods. The contractor’s means and methods, tight drilling tolerances, and an exploratory adit within the rock block made the construction uniquely challenging. Due to limited exploratory data and irregular rock face geometries, the design orientation, location, and tolerances of the tiebacks were established in a 3D Building Information Model (BIM). The 3D model was revised frequently during construction to 1) model the as-drilled conditions of the tiebacks; 2) compare with the remaining proposed anchors; 3) anticipate the contractor’s sequence to reduce risk during drilling; 4) accommodate the contractor’s requests for information; 5) make design changes based on field observations; and 6) incrementally assess rock block stability. The 3D model was created using BIM software and automated using custom programming to link per-plan, proposed, and as-installed tiebacks between the 3D model, field logs, and a stability analysis. This system allowed for a near real-time 3D model and stability analysis, which were easily communicated between the design team and field staff. This workflow and automated model nearly eliminated manual editing of the 3D model, accelerated contract document response time, and helped reduce risk for the owner, contractor, and engineer. Here, we present a successful case study utilizing the Observation Method and a real-time 3D model to complete a project with numerous complexities relating to design, communication, and risk.