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Jan 1, 1993

By Steven M. Henderson, Zachary D. Jones

The risk of allocation in construction contracts is a primary concern for all parties. For contracts involving subsurface construction the allocation of site condition risk is critical. In the past one hundred years technological advances fundamentally changed how that risk is allocated; yet another shift in this risk allocation may lie just over the horizon due to advances in geotechnical data management. Around the world initiatives are underway to make geotechnical datasets more open and accessible. In the United States some states like Kentucky have already made geotechnical data readily accessible. This proliferation of geotechnical data in the U.S. may impact the allocation of subsurface risk in construction contracts. Many construction contracts contain a differing site condition clause. That clause allows for a modification of the contract price or schedule if the ground conditions encountered by the contractor differ materially from either what was indicated in the contract documents or would be reasonably expected. A contractor, however, is typically not entitled to that modification if the contractor knew or should have known of the adverse conditions encountered. Courts have interpreted the “should have known” language as requiring contractors to make a reasonable site investigation prior to bidding the project. If geotechnical data is available and accessible and reveals the adverse condition the contractor encounters, courts could find that the contractor should have known of the condition and thus will not be entitled to a modification based on the differing site condition clause. Accordingly, the U.S. could be on the threshold of significant shifts in how the risk of differing site conditions is allocated in construction contracts.

Jan 1, 2017

After the Loma Prieta Earthquake, which caused major damage to viaducts in the Bay Area, the California Department of Transportation set up a test programme for foundation piles. Funderingstechnieken Verstraeten B.V., beter known as Fundex, was approached, since one of the piling systems of Fundex, named Tubex, is extremely suitable in areas sensitive to earthquakes and we were very much interested to prove the capabilities of this piling system. Equipment For the installation of Tubex and Tubex grout-injection piles special piling equipment is required. Since our company is not only a contractor, but also a designer and manufacturer of piling equipment, all special equipment for our range of foundation techniques is designed and built by our own piling equipment department. For the installation of both Tubex piles and Tubex grout-injection piles for the Caltrans test programme, the following pieces of equipment were selected: a) Fundex F12 piling rig b) Drill table c) Hydraulic powerpack d) Grout mixing unit and high pressure pump

Jan 1, 1993

By Lok M. Sharma, Deep K. Khatri, Bradfield. Brett

"A shored enclosure was required to access a control structure upstream below the dam of a deep lake. The shoring involves the interaction of the structure, soil, and water and the loads imposed include the hydrostatic forces of the water, soil pressures as well as dynamic forces due to currents and waves. Deep excavation support systems have traditionally been designed using classical methods that involve direct computations of earth pressures. However, traditional analysis does not take into account soil-structure interaction. Numerical modelling offers better means to analyze soil-structure interaction. This paper presents a 2D finite element (2D-FE) analysis of a deep excavation support structure that was required to remove and replace a control structure at the upstream toe of a dam. The sheet-piling shoring was designed to withstand the lateral pressures from 14 m deep free water and 5.5 m deep excavation below the free water to reach the required excavation level to replace the gate structure. Elastic-plastic analyses were performed to predict the stresses and deformations of the complicated shoring structure and excavation bottom. The soil parameters, procedures used to develop the 2D-FE model, and the results are discussed in this paper. The shoring system is currently under construction.INTRODUCTIONA deep shoring system enclosure is required to keep out water and soil and to provide a support for unbalanced loadings due to dewatering and/or, excavation in order to permit construction of the permanent structures in the dry. A braced shoring system consists of a single wall sheet piling which is driven into the ground to form a “box” around the excavation site and is braced on the inside. After bracing the sheet piling, seal concrete is placed into the bottom to prevent water from seeping into the open excavation from underneath the sheet piling, and the water is pumped out to provide the dry work area. The braced shoring involves the interaction of the structure, soil, and water and the loads imposed include the hydrostatic forces of the water, soil pressures as well as dynamic forces due to currents and waves. Deep excavation support systems have traditionally been designed using classical methods that involve direct computations of earth pressures, (active, passive, or apparent pressures). There have been some uncertainties regarding the actual distribution of earth pressures due to influence of the support wall flexibility, as these traditional methods do not take into account soil-structure interaction. Numerical modelling offers better means to analyze soilstructure interaction."

Jan 1, 2017

By Mathew Avery, Colby Barrett

In November 2016, a 7.8-magnitude earthquake caused more than 100,000 cubic meters of rock and debris to tumble down and bury the transportation infrastructure below Ohau Point in New Zealand. All routes between the northern and southern portions of South Island were severed. To undertake the rebuilding efforts, the New Zealand government established North Canterbury Transport Infrastructure Recovery (NCTIR) – an alliance to repair the road and rail networks between Picton and Christchurch. NCTIR’s aim was to have the road open by Christmas 2017, but work also continued into 2018 to complete a number of safety improvements along the highway. The presentation will review the initial remediation attempts, the necessity to re-evaluate the original efforts, the need to incorporate techniques that were “outside-the-box” and different from traditional methods, and the logistics and planning that were required to complete the work safely. INTRODUCTION Shortly after midnight on Monday 14th November, a magnitude 7.8 earthquake struck the small South Island settlement of Waiau in North Canterbury, 100km north of Christchurch. The quake was the largest in New Zealand since the magnitude 7.8 Dusky Sound earthquake in 2009 (GNS 2016). While shaking was widespread with over 15,000 recorded ‘felt reports,’ the worst shaking occurred about 50 seconds after the quake rupturing started. The energy of the tremor progressed north over several minutes with surface rupture recorded on a total of 21 faults. The length of all the fault ruptures combined was close to 100km (GNS 2016). The degree of ground shaking was high, recorded as Modified Mercalli Intensity Scale (MMI) Level 8 – Severe. This level of shaking causes considerable damage in ordinary buildings with partial collapse including fall of chimneys, factory stacks, columns, monuments, walls, etc. At a human level, people experience difficulty standing; while furniture and appliances shift. Geologically, the damage depends on the geological setting. In Kaikoura and the surrounding area, especially the coastal highway State Highway 1, north and south of the town, many of the slopes consist of over steepened weathered, fractured greywacke. During the quake, the shaking caused significant and widespread damage with a total of 26 major slips (and many smaller slips); closing both State Highway 1 and the Main North Rail Line between Picton and Christchurch.

Jan 1, 2018

By Ken Andromalos

Continued population growth combined with limited water resources in the Denver area has resulted in the conversion of a number of mined out gravel pits in the area into municipal water storage facilities. The use of slurry walls provides a cost effective means of isolating groundwater to convert these pits into efficient water storage facilities. Design considerations include: stability, underlying bedrock conditions, backfill mix design and earthwork requirements. Installation issues during construction include: trench stability considerations when excavating through relatively clean sand and gravel deposits in potentially high groundwater conditions; keying into three to ten feet of fractured claystone, siltstone or sandstone that makes up part of the Denver formation, and quality assurance procedures to assure a proper groundwater barrier is constructed. The paper concludes with two brief case histories to illustrate how these considerations are applied

Jan 1, 2007

By Fabian Kirsch

Cyclic behaviour of axially loaded piles has been an issue since studies revealed that the capability to transfer skin friction into the ground is highly depending on the level and the number of load cycles the pile is subjected. It has been shown that degradation of skin friction due to axial cyclic loading leads to accumulating displacements and a severe reduction in pile capacity. In Germany the DIN 1054 as well as the Recommendations of the Working Group 2.1 ?Piles? of the German Geotechnical Society (EA-Pfähle) require the consideration of cyclic loading for the assessment of both the displacements and the capacity. Up to now no broadly accepted design method exists, which enables the engineer to give a reliable judgement on the pile capacity under axial cyclic loading and the displacements respectively. Instead numerous design charts make it possible to distinguish between stable and instable loading levels in order to ensure a design on the safe side. A newly developed design approach based on engineering models is presented which delivers a calculation algorithm for the remaining axial pile capacity after a defined number of load cycles to allow for the analysis of stability of the foundation. Furthermore the computation of accumulating displacements is made possible. The results are verified with pile load tests undertaken at Dunkirk, France and showed that the axial capacity after cyclic loading calculated with the newly developed design approach predicts actual capacity with an accuracy of ±20%.

Jan 1, 2011

By Hessam Yazdani

In comparison to the conventional piled foundations, the piled-raft foundations provide a more economical solution to support high-rise buildings constructed on soft soils. In this type of foundations, the bearing capacity of the underlying soil is taken into account to support the superstructure loads and the piles are placed to control both the total and differential settlements of the superstructure. Currently, there is not a standard and worldwide acceptable approach to select the location of the piles and most of piled-raft foundations are designed based on the experience of designers. Therefore, particular attention should be given to the optimal design of this type of foundations in order to minimize the considerable construction costs involved. This paper examines the capability of the ant colony optimization (ACO) algorithm to optimize the piled-raft foundations subjected to static and seismic loadings. The soil-pile interaction is considered by modeling the side and tip resistance components of the piles using the nonlinear Winkler-based p-y and t-z curves in the OpenSees program. The soil-raft interaction is taken into consideration using the Winkler springs beneath the raft. The objective of the optimization problem is to minimize the construction cost of the foundation by taking the configuration and number of the piles as design variables. The side and tip forces of the piles as well as the total and differential settlements of the foundation under the serviceability limit state are considered as the constraints for the optimization problem. Results show that in addition to the type of analysis (linear/nonlinear), the regard or disregard of the soil-pile interaction in the analysis can significantly change the optimal solution. The optimal solutions obtained match the engineering expectations and indicate the effectiveness and capability of the ACO algorithm to minimize the construction cost.

Jan 1, 2013

By Feng Yongxuan

Anchored sheep pile is normally used in deep excavations, many of which only require stability in accordance with Terzaghi theory. In this paper, based on the experience, new lateral earth pressure method is adopted taking account into interaction among soil, anchors and sheet piles so that a group for the project under very difficult conditions and very severe requirments, especially, for the displacements are determined according to that mentioned above. During and after construction, displacements monitoring were carried out for about four months, which was proved that there was a little difference between calculation and practice.

Jan 1, 1991

By Brian Maroney

In this paper an overview of the California Department of Transportation's (CALTRANS) bridge design criteria is presented. Special emphasis is focused upon seismic design and retrofit criteria. Topics include earthquake load definitions, foundation and structure type selection, structural earthquake analysis, and structure behavioral requirements.

Jan 1, 1993

By Murray Gamble

A new type of groundwater cutoff wall has been developed at the University of Waterloo. The Waterloo Barrier? is a steel sheet piling system that incorporates a sealable cavity at each interlocking joint. In order to prevent leakage through the joints, the sealable cavity is flushed clean and injected with sealant after the installation of the piling. The installation and sealing procedures of the Waterloo Barrier? system allow for a high degree of quality control resulting in a very low permeability cutoff wall. Based upon field installations, the bulk wall hydraulic conductivity of the Waterloo Barrier? ranges from 10-8 to 10-10 cm/sec. Recent case histories are presented in which Waterloo Barrier? vertical cutoff walls have been used to prevent the off-site migration of contaminated groundwater or soil gases. In some instances, the Waterloo Barrier? system was used in combinations of applications such as preventing the migration of contaminants, redirecting the flow of groundwater, providing structural shoring for soil excavation and aiding in site de-watering processes.

Jan 1, 1997

? Hollow Stem Auger ? Drill Bits ? Leads/Torque Arm ? Hydraulic Gearbox ? Hydraulic Power Unit ? Grout Pump ? Crawler Crane

Jan 1, 1997

By Walter Ensinger

Working safely means working cost-effectively. Every "dangerous occurrence" and - even more so - every industrial accident causes disruptions in the planned course of construction. Besides moral and legal obligations, economic aspects are therefore also factors motivating increased efforts towards optimal prevention: improvements in work safety and protection of health are wise investments! Ever since its earliest days, the European Federation of Foundation Contractors (EFFC) has made this subject one of its key objectives and therefore set up a Safety + Environmental Working Group, in which experts from the member organisations exchange national experience and develop proposals for "best practices". The paper presents current developments and results from the work of the S+E WG with particular reference to the project "Ideas for Safety Improvement".

Jan 1, 2006

"TREVIICOS CorporationINTRODUCTIONThe Walter F. George lock and dam was constructed on the Chattahoochee River between 1955 and 1963 with the double function of improving navigation and generating power. Its 82 ft. by 450 ft. (25m x 137m) lock can accommodate large barge traffic and its four generating units with a plant capacity of 150 MW have an average energy output of 453,000 MWH. The dam consists of a 1,496 ft. (456m) long concrete structure housing the spillway, a non overflow portion, the power units and two earthen wing dams extending to the Georgia and Alabama sides, respectively 5,810 feet and 6,130 feet long (1770m and 1868m). As soon as the reservoir was impounded it became apparent that excessive seepage was occurring. From 1962 to 1985 a series of remedial works was performed using several techniques, but the problems continued under the dam, jeopardizing its generating potential and possibly undermining its stability.Finally, the decision was made to construct a deep cutoff primarily under the concrete portion of the dam to remedy the problem. PROCUREMENTOn July 5th, 2001 best and final offers were solicited by the Corps of Engineers (COE) for the construction of a deep cut-off to be built in front of the concrete portion of the dam from the bottom of the lake and tied into it. The cut-off had to cross an existing lock structure and an underwater retaining wall, as well as the remnants of a steel coffer cell left in place from the initial construction.The specifications required that the wall be built with a minimum thickness of 24” (600mm) and that it extended from the bottom of the lake to elevation -5 (1.52m) into the Providence formation, an impervious layer.While the land portions of the wall were on average 208 feet (63.4m) deep, the marine portion started from up to 90 feet (27m) of water and continued through different rock formations for another 100 feet (30m).Contractors were invited to propose their own method of constructing the cut-off and offers would be evaluated using several criteria, including technical, economical, organizational and experience.Three proposals were received and on August 14, 2001 an award was made to the Joint Venture (JV) of Treviicos and Rodio."

Jan 1, 2014

By Dennis J. Riley

A. This outline addresses what a sub-contractor, or a subsub-contractor should do to get paid in the event the general contractor or building owner files for bankruptcy. B. Negotiating payment terms. Progress payments vs. "pay when paid". How a sub or subsub can avoid financing the contract. C. Court interpretation of "pay when paid" clauses allow postponement not excusal of payment. See, e.g., Seal Tite Corporation v. Ehret. Inc., 589 F. Supp. 701 (D.N.J. 1984) (where the court held that the general contractor could not delay payment indefinitely to the subcontractor in the event of non-payment from the owner); United Plate Glass Co. v. Metal Industries. Inc., 525 A.2d 468 (Commw. Ct. Pa. 1987) (where the court held that payment from owner was not a condition precedent to paying subcontractor but instead a timing mechanism indicating when payment should be made); But see. Straham v. Landis Construction Co., 499 So. 2d 417 (La. App. 4 Cir. 1986) (where the court strictly interpreted the "pay when paid" clause).

Jan 1, 1991

By Scott C. Vollmer

This paper seeks to examine some of the technical factors influencing the deflection of Mechanically Stabilized Earth (MSE) retaining walls based on the authors' field observation of numerous structures. Excessive deflections can be unsightly and can be perceived as wall failure. Deflections can cause cracking or gapping of the facing units and general misalignment. Deflection of the reinforced backfill zone behind the wall face can result in settlement of the backfill zone and adjacent pavement cracking. Deflections can be the result of excessive movement external or internal to the reinforced soil structure. This paper only examines internal factors affecting wall deflections. External factors such as foundation settlement are not discussed.

Jan 1, 2003

By C. Vipulanandan

It is critical to monitor the ground conditions during excavation and drilling of boreholes during construction to identify possible changes in the soil and rock formations. Drilled shafts are increasingly used as foundations to support structures, bridges and other facilities in geomaterials such as soft-rocks and hard clays. Locating the bottom of the borehole during construction with the required design strength is critical. Hence developing a simple device that could be easily adapted/used with the drilling tool was of interest in this study. Determining the shear strength of the geomaterial in the borehole and at various elevations including the bottom of the borehole can lead to better quality control of construction by identifying the various layers based on strength. In this study, a down-hole penetrometer (DHP-CIGMAT) was designed, built, calibrated and tested in the field to determine its effectiveness in measuring the strength of soil/soft rock in the boreholes. Based on limited field tests, linear correlations between geomaterial strengths and DHP-CIGMAT deflection have been developed. The DHP-CIGMAT can be used to identify soils and soft rocks.

By George G. Goble

The use of augercast piles has been limited by the engineer's concern for the structural quality of the installed pile. The nature of the pile is such that its final structural continuity is very dependent on the skill of the personnel that do the installation. Thus, NDT methods have been used to verify integrity and when problems are indicated the available solutions are usually quite costly. If information were available during the pile installation so that immediate steps could be taken to correct perceived problems, the concerns of the engineer could be addressed and the system would gain increased reliability. Pile Dynamics, Inc. has developed a quality control system, the Pile Installation Recorder for Augered Cast-in-Place piles (PIR CFA). This system consists of the following devices as shown in Figure 1. 1) The Control Unit powers the sensors, conditions the signals from the sensors, records all measurements, takes input information from the operator, displays the results, and stores the recorded data on a flash card for later permanent storage and processing. During the use of the system all of the results obtained during a test are seen during recording and can be reviewed on the screen again after completion of the installation. The ability to review the measured information makes it unnecessary to print a copy in the field. Since printers often give difficulty in the construction site environment the ability to review the results quickly after completion of the installation is an important capability.

Jan 1, 1997

By G. Price

The Building Research Establishment installed a base load cell in a driven cast-in-place pile prior to it being tested under vertical load. The monitored base loads were found to be significantly less than could have been predicted by current design methods. The less than expected capacity was attributed to the drilling out procedure. An electro-level system installed in a second similarly formed pile, provided detailed information on the performance of the pile under lateral load. The information obtained was used to check several current design methods for laterally loaded piles. The findings show the potential dangers of attempting to improve design parameters from only limited performance data.

Jan 1, 2010

By Gao Dazhao

This paper presents some research results of pile foundation performance. Measurements on the bearing behaviour and driving effects of piles have been carried out during pile testing and pile driving. It has been found that the ratio of end resistance to the ultimate load depends on the pile length, and the ratio in general is less than 40% for single piles. However for pile group, the end resistance seems to be greater than skin friction. The characteristic curves of skin friction and end re­sistance appear as interaction between soils and pile. The contribution of skin friction to the pile bearing capacity not only depends on soil properties but also on the relative position of the soil layer. The pore pressure and the lateral pressure in ground have been observed during the stage of driving piles. Based on the available data, the radius of plastic region and the coefficient of pore pressure A can be found analytically. The pore pressure time process curves which may be used for practice have been predicted by means of numerical method.

Jan 1, 1991