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By Amanda R. Parry, Chris R. Pray

Predicting and modeling the soil structure interaction of laterally loaded piles with significant unbraced lengths is one of the challenges faced in designing many waterfront structures. Designers often rely on pile specific design software to calculate forces in an embedded pile and then couple that with either a structural design software to capture the behavior of the rest of the structure or use potentially overly conservative assumptions to omit modelling the piles entirely. Given that some projects have hundreds of piles coupled with hundreds of loading conditions, the shuttling of results from the structural analysis software into the pile analysis software can become cumbersome, difficult to track and manage, and prone to user input errors. An alternative approach recently used on two large marine infrastructure projects consisted of calibrating a structural analysis software to replicate the resultant outputs from a software developed specifically for pile analysis. This calibration was done using thoughtfully placed springs along a pile modeled in the structural analysis software to replicate the soil-structure interaction of the piles. The focus of this paper will be on the methodology used to calibrate the two software programs and an evaluation of the results which showed close agreement. Based on the two case studies, calibrating a generic finite element analysis software via this method should be considered as a reasonable and time saving design approach for pile-supported structures.

Sep 8, 2021

By Sven Schröer, Lilma Schimmel, Dimiter Alexiew

"The Geotextile Encased Columns (GEC) deep foundation system for embankments on soft soils was introduced some 20 years ago and is now considered State-of-the-art worldwide.The GECs consist of compacted granular fill, similar to common gravel columns, with one decisive difference: they are confined in a high-strength low-strain flexible geotextile “cylinder” (encasement). This engineered element provides a very efficient tool to control and optimize the behavior of the system. GECs perform very well even in extremely soft soils ensuring bearing capacity (stability) and reducing settlements. Due to the encasement, they a lso provide high lateral ductility. A wide range of fills including sands can be used.The remarkable reduction of vertical stresses in the soft soil surrounding the GECs results in a decrease of lateral pressure as well. Such reduction combined with the lateral ductility allow GECs to be also used for lateral pressure-relief adjacent to sensitive foundations, e.g. rigid piles. The application of GECs as lateral pressure relief was recently used in Brazil and Germany where bridge abutments were built on concrete reinforced-piles. The GECs below the bridge approaches and adjacent to the piles decreased the lateral pressure to acceptable values.This paper presents two case studies for which the most relevant parameters, the geotechnical conditions, specific problems, engineering philosophy, final solution and lessons learned are discussed. Furthermore, instrumentation programs were applied in both projects. The most important results in terms of displacements and stresses are shown, evaluated, summarized and commented upon, focusing on the lateral stress-relief, followed by conclusions and recommendations."

Jan 1, 2016

By K. Madhusudan Reddy

Pile response under combined uplift and lateral load is very important and it is imperative to evaluate the effect of combined loading and only few studies were reported on pile behavior under combined uplift and lateral loads. Model pile made-up of aluminum having an outer and inner diameter of 25.4 mm and 19.4 mm respectively is used. Dimensions of the model steel tank are fixed as 1.0 m x1.0 m x 1.2 m (depth) to avoid the boundary effects under combined lateral and uplift loads. Experiments were carried out on single piles at isolated uplift, isolated lateral loading and combined lateral and uplift loading, embedded in sandy soil. Results indicate that load?deflection behavior is nonlinear for isolated uplift and lateral load tests as well as in case of combined loadings. It is also observed that the behavior of piles under isolated loadings is substantially different when compared to combined loading.

By Brian Koch

Michels installed 242 drilled shafts to support the piers for a new basket-handle, true-arch twin bridge across the Mississippi River from Moline, IL to Bettendorf, IA. The installation of the drilled shafts was completed with the simultaneous use of two Liebherr LB36 and one IMT 300 drill rigs. Utilizing barges, 233 drilled shafts were installed in the river. Michels crews also installed 7-ft to 10-ft permanent steel casing into the bedrock, and drilled to depths of 60 feet for each shaft. Despite working in strong currents, freezing temperatures and on rocking barges, Michels crews placed the shafts within 3 inches of plan position. Since the drilled shafts are the key piece in supporting the bridge structure, Michels provided cross-hole sonic logging to verify the integrity and strength of the concrete within the shafts and to add another level of quality control for the owner/customer. Extensive planning took place each day to ensure that tugboats, the linchpin of the project, were being efficiently utilized to shift the barges and materials daily. On any given day, Michels transported five concrete trucks by barge from shore to shaft sites to pour between 40 and 240 cubic yards of concrete. The Michels environmental team was diligent with preparing, discussing and implementing a water treatment plan that was accepted by all state and federal agencies and adhered to strict environmental regulations. Grain hopper barges were rented to control and treat the water that was used in the drilling operations. Another challenge crews ran into was the discovery of caverns when drilling into some parts of the bedrock. Michels worked with the engineer to develop a plan to construct the drilled shafts that encountered the caverns.

Jan 1, 2019

By Randy R. Williams, Brian W. Wilson, George M. Filz, Marina S. W. Li

"Detailed design of an extensive deep mixing (DM) scheme using the Cutter Soil Mixing (CSM) technique was completed for foundation support of mechanically stabilized earth (MSE) walls for Kitimat Liquefied Natural Gas (LNG) at Bish Cove, British Columbia, Canada. The design was based on the provision of soil-cement structures, constructed in highly variable subsurface conditions that consisted of thick deposits of fine-grained soils overlying granular soils, and required to meet project-specific performance criteria, to support the MSE walls. The design, consisting of rectangular CSM panels constructed to form barrettes connecting to a longitudinal wall of continuous CSM panels, was configured to manage the distribution of stresses and strains that could be developed within the soil-cement structure.The results from 2D finite element analyses were used to determine the necessary arrangement and properties of the CSM panels to accommodate localized areas of relatively high shear, tensile and compressive stresses within the soil-cement structure. The relationships between unconfined compressive strength and elastic modulus for fine-grained and granular soil-cement structures obtained from the Bish Cove data were compared with published references and were found to be significantly different in the higher strength range materials.BACKGROUNDDeep Mixing design was completed for the development of the Kitimat LNG Facility located in Bish Cove, British Columbia, for support of two relatively high MSE walls and associated bulk earthwork operations. Deep mixing was necessary to treat the very weak native deposits in-situ to meet project performance requirements and physical constraints without the need for significant excavation and disposal work. The DM design was undertaken on the basis of adoption of the CSM technique for in-situ ground improvement of the native foundation soils which consisted of very soft to soft fine-grained marine deposits and loose to compact sandy silt to silty sand, overlying dense sand and gravel (Fig. 1). The DM area is located immediately upslope of the Bish Cove beach area, and is “L” shaped in plan, approximately 300 m long by approximately 28.8 m wide (parallel to the beach area) and 165 m long by an average width of 21.0 m (perpendicular to the beach area). The depth of the DM ranged from about 5.0 m to 30.7 m with typically 2.0 m embedment into dense granular soils. Details of the design philosophy, including an overview of the DM design and the project background information are presented by Li et al. (2014a). Details of the construction aspects of the Kitimat LNG deep mixing are presented by Wilson et al. (2014)."

Jan 1, 2015

By Bernardo J. Jiménez Vega, Edy L. T. Montalvan PhD

The experience gained during more than 900 Crosshole Sonic Logging (CSL) tests on drilled shafts shows the importance of establishing proper project acceptance and repair protocols. Drilled shaft evaluation is a multidisciplinary task that should not be left solely to the outcome of the CSL test. This test allows to characterize and delimit areas of different qualities of concrete, and it is important that all the interested parties understand the difference between flaws and defects. The information presented here is intended to give a guideline to contractors, inspectors, engineers, owners and clients on how to deal with acceptance and remediation of defective drilled shafts, detected using CSL tests. A database of flaws is presented depending on their location, intensity and remediation method. Procedures that allow the flaws to be analyzed are presented in order to dismiss or classify them as defects. In many cases, the CSL test may indicate an anomaly, but by coring the concrete and analyzing the structural demands and conditions, the flaw can be classified as non-severe. When flaws are classified as defects, their repair will depend on the area where they are located in the drilled shaft pile. In this document two procedures are described for repairing defects depending on their location. For defects in the drilled shaft head area, the procedure takes into account the interaction between the new and old concrete. For repairing the middle zone of the drilled shaft by grouting, the major concerns are the difficulty of accessing through the drilled shaft at deep depths and the communication between boreholes. For defects at the drilled shaft tip, two proposed remediation methods are presented. Finally, tomography tests are presented to compare the effectiveness of remediation by grouting.

Oct 1, 2022

By A. Daugiala, D. Coleman

In 2014 the New York State Department of Transportation (NYSDOT) awarded a Design-Build contract to the joint venture team consisting of Skanska which is the managing partner; Kiewit Corporation and Ecco III (SKE) and HNTB as the lead design firm. The design build team employed methods to provide schedule savings and commercial benefits to the owner NYSDOT. This paper presents the design approach and construction methods used to accelerate drilled shaft installation supporting the main span foundation for the cable stayed bridge. The drilled foundation contractor Underpinning and Foundation Skanska, a division of Skanska was responsible for assisting with design, budgeting and construction of the drilled shaft foundation construction. As part of the Request for Proposal (RFP) bid process, Alternate Technical Concepts (ATC) was encouraged by the NYSDOT. The JV team proposed an ATC which involved a scaled production shaft testing method to simulate the ultimate load level, commonly referred to as the “Chicago Method” was used in the rock socket employing the Osterberg Cell (O-Cell) testing procedures. To the authors knowledge this was the first NYSDOT project where this approach was utilized on a Demonstration/Production installation to validate construction procedures and load bearing capacities. Construction procedures, challenges and solutions are discussed in detail. Upon completion of successful drilled shaft construction, concrete integrity is verified using two methods – Cross Hole Sonic Logging (CSL) and Thermal Integrity Profiling (TIP). A comparison from the contractor’s perspective is provided. Finally the drilled shaft rock socket is tested to ultimate end bearing values while rock socket side shear stresses are not exceeding the service level loading. Lateral load test was also a RFP requirement; the test arrangement and performance are discussed in detail as well. The Kosciuszko Bridge location poised unique geotechnical challenges on many levels shifting towards an extreme boundary of parameters encountered in New York City Area for drilled shaft construction. The JV team and specialty drilled shaft contractor actively participating in the shaft design and construction practice coordination and working with NYSDOT yielded a successful foundation solution which provided cost and schedule savings to the project.

Jan 1, 2016

By Nicolas Denies, Jeroen de Leeuw, Bart Lameire, Jan Maertens, André Vervoort, Flip Hoefsloot, Noël Huybrechts, Flor De Cock

"In recent years, the Deep Mixing Method has increasingly been applied for the construction of earth and water retaining structures. From practice, it has been experienced that there is a real need to develop execution and design rules adapted to the function of the soil mix wall (retaining wall, water barrier, foundation solution or a combination) including the temporary or permanent character of the application. Based on the results of the BBRI Soil Mix project (2009-2013), a design approach has been developed in collaboration with the SBRCURnet. The present paper briefly discusses the principles of this design approach which takes into account the function of the soil mix wall and the characteristics of the soil mix material. The interaction between the soil mix material and the steel reinforcement can be considered in the calculations depending on the function of the soil mix wall. Design and quality control requirements are given in function of the application and take the lifetime of the structure into account. Durability aspects of the soil mix material are therefore considered in the present design approach.INTRODUCTIONSince several decades, the deep mixing method is used for ground improvement works. A more recent application is the use of soil mix as structural elements such as in the case of the earth-water retaining soil mix walls. Since 2000, due to the economic and environmental advantages of the method, this particular application has shown an amazing growth in Belgium and in the Netherlands. A typical excavation (16 m depth), realized with CSM (Cutter Soil Mix) panels, is shown in Fig. 1. For temporary applications, the questions related to the mechanical characteristics of the material, its permeability and its adherence with steel have been investigated with success within the framework of the BBRI Soil Mix project (2009- 2013) (see Denies et al. 2012 for more details). The durability of the soil mix material remains a complex topic while permanent applications are more and more observed in practice. In order to define an obvious design approach, it was necessary to clarify the potential functions of soil mix walls and to establish the requirements related to their design and construction. The BBRI (in Belgium) and SBRCURnet (in the Netherlands) have therefore worked together to publish guidelines in the form of a handbook titled ‘Soil Mix Walls’ (publication foreseen in 2015). In this handbook, a methodology is proposed for the design of the soil mix walls for which the interaction between steel and soil mix can possibly be taken into account dependent upon the application. Each potential function of the soil mix wall is described (e.g. earth retaining wall, cut-off wall, etc.) and the temporary or permanent character of the application is always considered."

Jan 1, 2015

By I. D. McPherson, Dominic P. Mahoney

The Metro Sports Facility is currently under development in Christchurch, New Zealand and is a key Anchor Project in the city’s post-earth quake recovery. When completed it will be largest indoor sports and swimming pool complex in New Zealand, with a building footprint in the order of 22,000m2. The site is underlain by poor performing soils comprising interbedded layers of soft compressible silts and loose liquefiable sands to over 20m depth. The site is typical for Christchurch with a shallow groundwater table and artesian conditions. The site performed poorly during the 2010-2011 Canterbury Earthquake Sequence with extensive liquefaction, and associated ground damage. To provide a resilient and economical foundation system for this key development project, deep ground improvement comprising of a uniform grid of some 7,200 stone columns in conjunction with robust shallow foundations has been adopted. This paper discusses the geotechnical site constraints, and ground performance under earthquake loading and describes the various options considered for the development. The foundation option selected, the design considerations of the adopted stone column ground improvement, and foundation solution are described in detail, as well as, construction observations. The paper aims to provide insight into an urban large-scale ground improvement project for the engineering practitioner.

Nov 1, 2022

By Carl-Oscar Nilsson, Åke B. Nilsson

"The embankment dam at Storfinnforsen is 23 m high and was completed in 1954. The dam has an impervious zone with timber sheet piles and a support fill of glacial till. The pore water pressure in the downstream shoulder has during recent years increased due to deterioration in the sealing function of the timber sheet piling. There is a concern that the high pore water pressure in the glacial till will cause internal erosion initiating at a thin coarse transition layer between the glacial till and the rock fill along the downstream toe. As a remedial action in order to improvement of the leakage resistance a supporting berm of coarse rockfill against the downstream slope of the dam was constructed in year 2013. In addition a new impervious seal in the centre of the dam e.g. a diaphragm wall was considered. However, after further studies and a trial stretch of 40 drains each 20 m long and diameter 0.3 m an alternative with vertical drilled drains in the downstream support was selected. A contract has now started up to drill in a similar way to treat the full length of the dam with drains. The work is in the planning to be completed in 2016.Dam ConstructionStorfinnforsen Embankment Dam was put into operation in 1954. The dam is 330 m long and maximum height is approximately 23 m. The dam is constructed with a central core zone and supporting zones of earth and rockfill on the upstream and downstream sides giving an almost symmetrical cross-section about the dam axis, see Fig. 1. The upstream slope is 2H:1V down to el. 270 and 2.5H:1V below. On the downstream side the slope is 1.75H:1V down to +269 and 2H:1V below. The core zone consists of a timber sheet pile wall with a Zone 5 of glacial till, approximately 2 m wide, adjacent to the wall on the upstream side."

Jan 1, 2016

By Michael W. Neill, O&apos

This presentation addresses some of the problems encountered in estimating the capacity of drilled shafts and augered, cast-in-place piles in soft rock. Methods to quantify side and base resistance are suggested. However, the methods that are described should always be verified locally by performing load tests.

Jan 1, 2001

By Dalia. R. Mohamed, Hisham H. Hafez, Marawan M. Shahien

"Construction activities in major projects that involve deep excavations necessitate the use of vertical walls surrounding the construction site to play an important role as earth retention system. The walls are usually partially penetrating impervious walls which can increase the efficiency of the ground water control system that usually consists of number of partially penetrating wells. The analysis and design of such system requires 3D numerical simulation. The aim of this study is to develop simplified semi-empirical approach to analyze and design such system. The analyzed model is a single well in a square site that is surrounded by impervious walls along the perimeter of the site in an unconfined aquifer. The results of the parametric analysis are presented in this paper aiming to assess and understand the factors that influence dewatering in terms of ground water or drawdown profile surrounding the well. The parametric analysis is carried out using the 3D finite difference software. The parametric analysis comprises with more than 550 cases calculated. The study involved the parameters; well penetration depth, impervious wall penetration depth, size of the construction pit, coefficient of permeability, well yield and well location or distance between well center to impervious wall edge.IntroductionThe presence of groundwater in a site may have impact on the construction processes involved during the course of project construction, especially those projects that involve deep excavations. Deep excavations, especially in urban areas, require the construction of supported walls all around the site perimeter to ensure the stability of the excavation. In most of cases, the constructed walls are relatively impervious. Depending on the ground and site conditions, the walls are not penetrating all the way down through to the bottom of the aquifer and thus the walls are partially penetrating walls. The presence of ground water necessitates the lowering of the groundwater to levels below the bottom of the excavation to ensure working in dry. This paper focuses on groundwater control systems that consist of deep wells inside square areas enclosed by impervious walls partially penetrating unconfined aquifers. The wells are partially penetrating the aquifer, as well. There are many factors or parameters that are related to the configurations of the components of the system that may influence the drawdown of a well in such groundwater control system. This paper is a part of a comprehensive study that aims to development of a simple method for estimating the drawdown of dewatering system of the described configuration. In order to achieve such a major goal, a 3D finite difference model is developed for the problem in hand. A comprehensive parametric analysis was then carried out to investigate the influence of all the parameters on the drawdown of a deep well in such groundwater control system. This paper describes the problem, the model, the parametric analysis including the involved parameters. The paper, then, demonstrate the results of the analysis showing the influence of the studied parameters on the drawdown of a single well."

Jan 1, 2016

By Ryan Sullivan, Lisa Smiley, Jewels Stover

The Westerly Storage Tunnel (WST) Project is part of Project Clean lake, the North East Ohio Regional Sewer Dist years. When completed in 2020, WST will be nearly 2 miles of 25-ft diameter tunnel 200-250 ft below ground. The storage tunnel will manage higher flow volumes, keeping stormwater out of the combined sewer system reducing overflow occurrences. Three deep shafts provide access to the tunnel at the tunnel boring machine (TBM) launch and retrieval sites, as well as a vent shaft. Support of excavation for the access shafts was constructed utilizing unreinforced concrete diaphragm walls. This innovative, value-engineered alternate design significantly reduced risks associated with conventional secant piles combined with a rib and liner plate system. Implementation of the diaphragm wall technology resulted in a water tight, continuous shaft keyed into rock. This case study examines the design, methodology, and installation challenges unique to each shaft, as well as the benefits of the final product to the overall project.

By Shawna Munn, Carol Dounitch, Erika Acton

The EQ Bank Tower, a 24-storey office tower with 4 levels of underground parking, is currently under construction at 25 Ontario Street in the downtown core of Toronto, Canada. The tower geometry required an 18 m (60 ft) deep excavation inside an existing 3-storey 100-year-old façade, to be retained in place throughout construction. This presented a variety of design challenges that required several innovations and a customized monitoring program. In this paper, we will discuss two major challenges, and highlight the innovative and adaptable solutions carried out using performance-based design leveraging the observational method. The first was installation of a shoring system in a 500 mm (20 in) gap between the historical façade and a live gas main. The second involved excavating 10 m (33 ft) into expansive shale bedrock adjacent to a sensitive neighbouring building.

Oct 1, 2022

By Abhirami B., V. Balakumar

Piled raft foundation system is an intelligent geotechnical concept, developed towards reducing the settlement of the raft and the footings by providing pile elements below the raft or footings, as the case maybe. Although a large volume of works has been done on the behaviour of piled rafts by observational studies, the effect of construction methodologies such as deep excavations, the installation methodologies used for piling etc appear to have not been covered adequately. This paper discusses the effect of deep excavations, pile installation techniques and the effect of adding structural elements, based on the data available from published literatures. Based on this study, the performance of the piled raft monitored by the author has been revisited and the results of such a study are discussed.

Nov 1, 2022

By Sudhir Kumar Das

"The exorbitant price of the land in the metropolis has restricted the horizontal expansion and compelled the owners, the developers and the engineers to opt for vertical expansion. This has resulted in the construction of high rises by extending floors of the existing buildings and developing the new ones for which deep excavation is a must. The multistoried buildings up to a certain height can be founded on shallow depth if the soil beneath can withstand the load. If not, the soil can be stabilized by the latest improvement technology to change the properties of soil to cater the desired load of the superstructures. By such practice the cost and time of completion of the substructures can be reduced in comparison to the substructures needed for deep excavation.The necessity of deep excavation cannot be ignored to create housings, underground parking lots and the other public amenities for the urban migrants in the metropolis.Although most of the metropolis have underground mapping the developers, before starting excavation should be hundred percent sure about the alignment and depth of the utilities so that the excavators do not snap the same to bring cut in water supply, power lines, telephone lines etc, resulting in hue and cry in the neighborhoods of the metropolis due to no availability of the essential services The building/structures coming on the influence zones of the deep excavation should be monitored in all sequences of excavations. In case of building underground corridors for rail or road through open deep excavation under a traffic road the developers, before commencing excavation should shift/divert the dry and wet utilities coming on the way of excavation to suitable locations. The surface traffic need to be diverted either temporarily to an adjacent alternative road or allowed to pass over a decking built over the trench of excavation for the affected length of construction. The soil support system is necessary longitudinally on the two sides covering the width of trench for building corridors. In case of building substructures of flyovers built at different plots along the alignment of the flyover or a multistoried complex built at an isolated plot, the soil support system would be necessary on all the sides covering the plot of construction.The material of construction of soil support depends on the depth, type of soil and the type of permanent structure to be developed. Probable geo-hazards inviting casualties in the deep excavation projects occur due to caving of soil, leakage of wet utilities, seepage through honey comb concrete surfaces, failure of pump used for dewatering etc. A detailed comprehensive planning, management and determination of the project authority is essential for marginalizing the casualties. These prevent unforeseen expenditure in mitigation and help to control the time and the cost over run of overall project. The engineer at site should be more a professional manager than an engineer at site. He should be conversant with the safety and environment rules and regulations applicable to deep underground projects."

Jan 1, 2015

By Gustav Jahner, Michael Baltrusch, Norbert Hoffmann

Near the port city of Whitby in the north-east of England, Anglo American (AA) is setting up the deepest mine in the UK, which will have a depth of 1,500m. The purpose of the project is to extract and transport polyhalite, both underground, and to market it globally. As part of the construction works, BAUER Technologies Ltd, the UK subsidiary of BAUER Spezialtiefbau GmbH, constructed three different shafts using the diaphragm wall technique, with depths of up to 120m. In order to ensure the specified vertical tolerance of maximum 200mm, several measurement methods were applied, and the results were documented in a 3D model. Complex de-sanding plant technology and specially developed polymer products were adopted to regenerate the trench supporting bentonite-slurry.

Sep 1, 2022

By Stephan Jefferis

It is my understanding that the Scandinavians have done some fundamental work on durability. I have seen a study published whereby the author, Helen Anderson, comments on the durability of polyurethane grouts and there was -if I am not mistaken- a reference made to another Scandinavian testing institute comparing durability of the polyurethane to cement grout under the same type of circumstances. Circumstances are important so we should actually ask the gentleman to shed some light on this particular method because apparently Scandinavia is the place where durability has been taken very seriously and has been well researched.

Feb 10, 2003

By T. Wulleman, M. Ansriou

Integrity testing is a primary quality control check on a product that is for the most part not accessible to visual examination. Their cost can be expensive when using direct methods of inspection (like coring a pile) or more economical when using indirect methods (e.g. acoustic testing). All indirect methods operate by “inference” which means that they do not directly measure the defect of integrity. Indirect methods measure the variation of physical values (temperature, impedance, speed, ect.) correlated to the integrity of the pile allowing the detection of integrity defects, although these methods do not allow for the characterization of the defect. 1. INTRODUCTION Cast-in-place piles are particularly prone to integrity defects. The reasons for this are multiple, including lack of high quality of contractor workmanship, experience and supervision necessary in construction, variable soil and groundwater conditions on site, etc. Furthermore, visual inspection of the finalized pile is usually impossible. Therefore, special care has to be taken both during the execution process and during the subsequent quality control campaign to detect any defects of executed piles. Today, a lot of methods do exist to assess pile integrity. It is thus essential to understand the mechanism governing those devices to both make an engineering choice of the pile integrity testing method and to interpret correctly the provided results. 2. QUALITY IN PILE FOUNDATIONS 2.1 Pile anomalies A pile having an anomaly is a pile which has a different behavior from what is normally expected. The presence of a pile anomaly does not necessarily imply that a pile cannot be used for its intended purpose (Gordon & Chapman 2004). An anomaly can be considered as a defect, or a “performance” depending on the ability of the pile to fulfil the following three criteria (3C): C1 - Meet the Service Limit State (SLS) requirement and support the proposed working load without settling more than admissible by the superstructure ; C2 - Meet the Ultimate Limit State (ULS) requirement and carry a specified load with an adequate factor of safety against failure ; C3 - Remain durable throughout the design life of the structure such that the pile is not affected by time dependent activities (chemical attack, corrosion of steel reinforcement, ect.), which would jeopardize its ability to maintain its compliance with the first two criteria.

Jan 1, 2019

By Krishna R. Reddy, Jyoti K. Chetri, Girish Kumar

Geotechnical engineering encompasses a major portion of the civil and infrastructure projects. The large amounts of energy and resources typically used in these projects leads to undesirable emissions and wastes which contribute substantially towards global environmental impacts (e.g., global climate change). This could further include secondary economic and societal issues which are often unaccounted in traditional engineering design of the geotechnical projects. In order to address this issue, it is imperative to integrate the broader environmental, economic and social implications into decisions of a geotechnical project. Recent years have seen a major impetus on life cycle assessment to evaluate the environmental sustainability of the geotechnical designs. However, there are no tools that can quantify the life cycle triple bottom line sustainability of potential design alternatives in a project with holistic considerations towards broader economic (indirect costs and benefits) and social impacts (stakeholder preferences, socio-environmental and socio-economic impacts). This study presents a new framework for quantitative assessment of life-cycle sustainability (QUALICS) for alternative designs in engineering projects. The framework integrates two multi-criteria decision analysis methods namely, the Integrated Value Model for Sustainable Assessment (MIVES) and Analytic Hierarchy Process (AHP), to support decision making on the potential design alternatives. In this study, a brief overview of the framework is presented. A case study demonstrating the use of QUALICS framework is discussed with its application to the sustainability assessment of two deep foundation systems, caissons and piles, over their design life. The technical designs of both systems are developed based on bearing capacity, both primary and secondary settlements, and structural integrity. The results from the sustainability assessment of the two deep foundation systems are discussed, and the most sustainable option based on different stakeholder preferences and site-specific conditions are identified.

Jan 1, 2019