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The serviceability limit of the foundation system plays an important role in the safe long-term performance of a building. Under governing load cases in service life, the building foundation system should satisfy the serviceability limit state, i.e., total and differential settlement criteria. This study investigated the distress of a building through foundation performance assessment incorporating the soil–foundation–structure interaction (SFSI) effects. A spatially variable soil model [zonewise, obtained from field observation and electrical resistivity tomography (ERT) study] was used to obtain the settlement of the foundation system. Engineering properties of the subsurface were estimated from the collected soil samples and field tests. ERT result shows the variability of the subsurface layer. A three-dimensional finite-element model of soil, foundations, and structures was developed to estimate the settlement demand of the foundation and structures. The numerical model includes the geometric variability of all the foundations of the building and subsurface variability. Settlement and bearing capacity demand of the foundations were estimated and compared with the standard provisions. Results obtained show that the building foundation system satisfies the serviceability limit of the foundation system under total settlement criteria. However, the differential settlement of the system exceeds the required limit despite considering the SFSI effects, and is one of the major causes of distress to the building. The main contributions of this study also include establishing the spatial variability of the soil layer through ERT and correlating it with the crack zone in the building. [ABSTRACT FROM AUTHOR]

This document is a closure to a case study on ground subsidence caused by the drying effect of Australian native eucalypts. The study highlights the potential for clay soil shrinkage and subsequent damage to structures such as residential buildings, road pavements, and pipelines. Recommendations for addressing the drying effects of trees on nearby buildings vary by country, with the Australian standard AS 2870 providing guidelines for designing footings near trees. The closure also addresses potential queries from practitioners, including the age of the trees, the construction date of the netball court, and the impact of cutting tree roots during barrier construction. The writers express gratitude to Dr. Vishnu Diyaljee for their insights and thank the discusser for their valuable questions and additional insights. [Extracted from the article]

This article discusses a case study on the effects of ground subsidence caused by the drying effect of a group of Australian native Eucalyptus trees near a netball court. The study demonstrates the impact of evapotranspiration on the cracking of the court and highlights the importance of monitoring sap flow from trees to understand water movement. The article also compares the recommendations for tree placement near infrastructure in Canada and Australia, emphasizing the need for geotechnical engineers to consider the influence of trees on foundation distress. The study suggests the use of root barriers and collaboration with agriculturists to mitigate tree-induced suction and prevent settlement issues. The article concludes by calling for a reevaluation of the Canadian Foundation Engineering Manual to address the influence of trees on foundation behavior. [Extracted from the article]

Soft soil foundations are often encountered in engineering construction. To make the foundation meet the engineering strength and deformation requirements, the soft soil foundation must be treated. Based on bucket foundation and silt solidification technology, the new grid composite foundation is proposed. The strength improvement mechanism of the new type foundation was analyzed according to the Mohr-Coulomb strength theory, and numerical simulations are used to carry out research on the bearing characteristics of the grid composite foundation. By carrying out load simulations for the grid foundation with different foundation widths, the failure modes corresponding to different B/L were analyzed. With overall consideration of the side length of a solidifying grid, the foundation width, and the undrained shear strength of the soil mass, the calculation method for the bearing capacity of the grid composite foundation has been proposed. Moreover, a wall strength check is carried out according to the maximum pull stress of the solidified wall. In the field test, the results of the finite element simulation and the field test are in good agreement, further verifying the feasibility of the grid structure foundation. Thus, a theoretical reference for engineering design is provided. [ABSTRACT FROM AUTHOR]

This paper presents a case study of applying a new device termed deformation adjustor in piled raft foundations to support a highrise building. The deformation adjustors are mounted on a pile head to optimize load distribution of a piled raft foundation so that a relatively uniform foundation deformation can be achieved in complicated load, construction, and soil conditions. In this case study, the project site is located in a coastal city in China, featuring complicated subsurface soil conditions with abundant large boulders. The project was put on hold for a decade because in the complicated soil conditions the piles could not be installed to the required depths. The project resumed with introduction of deformation adjustors which helped to shift the applied loads from piles to subsoil below the raft and thus considerably reduced the pile lengths. This case study describes the preliminary design of pile-raft foundations with deformation adjustors, followed by a comprehensive monitoring program for settlements, earth pressures, and pile top reaction forces during and after building construction. Based on the long-term monitoring, subsoil below the raft was able to bear 83% of total applied loads, whereas the piles carried 17% of the loads. Based on this case study, deformation adjustors were proved to be an effective and economical solution for piled raft foundations to support high-rise buildings in complicated subsurface conditions. [ABSTRACT FROM AUTHOR]

The lifecycle analysis and assessment of concrete structures requires an efficient evaluation and prediction of time-variable mechanical and chemical degradation processes. Inspection systems and novel monitoring methods are of valuable support in these important tasks, but due to their practical feasibility and the costs that they entail, they also present limitations. Therefore, information gathered with inspection methods for structural performance assessment needs to be used in the most effective manner possible, e.g., with respect to serviceability limits, bearing capacity, robustness, and redundancy of a given structure, among others. The aim of this paper is to present a framework for the prediction of time-dependent performance indicators of concrete structures prone to fatigue, with emphasis on a wind turbine foundation, including reliability. A theoretical background and selected structural performance indicators as well as associated lifecycle prediction methods--incorporating inspection and monitoring information--are presented. [ABSTRACT FROM AUTHOR]

This paper describes a systematic approach of inspection, diagnosis, and repair for masonry walls and their claddings, aiming at facilitating the inspection process and deciding on the repair of these elements. It also helps to combat their degradation. Based on a visual analysis, the inspector is able to identify anomalies and use the proposed system tools to establish correlations with its source, delineate an accurate diagnosis, and determine the best repair technique. The tools that allow a faster and simpler inspection and decision are presented here. The nature of the anomalies, their related causes and appropriate repair techniques are classified, listed, and then related through correlation matrices to create a database. This equips the inspectors with the information they need about the pathology in masonry walls, as well as its classification through suitable terminology, so that a statistical analysis can be performed to find the chief causes of the anomalies. The system was developed under a strategy of proactive maintenance, and it represents an innovation that is as useful to rehabilitation in southern Europe as it is in other regions where masonry walls are a widely used technique. [ABSTRACT FROM AUTHOR]

Successful waterproofing of concrete foundations prevents the degradation of environmental and health conditions and of building materials used in belowground stories and extends the service life of concrete constructions. However, despite the important role of waterproofing systems for concrete foundations and the fact that repairing them is either impractical or prohibitively expensive, there is very little useful information or discussion on membrane properties and the detailing required for a durable, watertight design. This paper presents a discussion of the requirements of waterproofing membranes and the auxiliary components used in waterproofing systems for concrete footings, mat-slabs, and pile foundations, along with a schematic representation of suggested systems and their detailing. Flexibility and mechanical resistance are particularly important and reasonably well-documented properties of buried waterproofing membranes, but knowledge of their long-term durability presently relies mostly on empirical data. The cost analysis of some of the suggested waterproofing systems revealed significant differences that, along with the other data presented, should aid building designers and contractors with the design and installation of effective waterproofing solutions for concrete foundations. [ABSTRACT FROM AUTHOR]

The performance of road bridges undergoing liquefaction in the foundation soils and substantial lateral spreading during the 2010-2011 Christchurch earthquakes is discussed in this paper. Three, well-documented case studies are presented in detail to illustrate the performance of bridges and their typical damage associated with lateral spreading. The short-span bridges on pile foundations have a very stiff superstructure (deck), which was a key factor in the seismic response of the bridges. It led to a characteristic deformation mechanism for all bridges involving lateral spreading-deck pinning-abutment backrotation with consequent damage to the abutment piles and slumping of the approaches. Overall, road bridges performed relatively well in the 2010-2011 earthquakes compared to other engineering structures, despite the high seismic demands including substantial liquefaction and large kinematic and inertial loads due to spreading and strong ground shaking, respectively. [ABSTRACT FROM AUTHOR]

The exposure of pier foundations owing to scour significantly reduces the foundation-bearing capacity and diminishes the flood-resistant capacity of a bridge. This paper proposes a nonlinear quasi-static analysis procedure for the performance of bridges with pile foundations under flow-induced loads for the evaluation on the flood-resistant capacity of scoured bridges. The Winkler beam model is adopted for the modeling of the pile-soil system, and the distributed hinge model is utilized to simulate the possible flexural failure of the piles. Soil springs with nonlinear curves are used to represent the nonlinearity of the supporting soil. To demonstrate this procedure, a case study on the Shuang-Yuan Bridge in Taiwan was performed for various flood and scour conditions. This bridge was partially demolished in a major flood event caused by Typhoon Morakot in 2009. According to the analysis results, a possible scenario for the failure of the Shuang-Yuan Bridge is presented, and the proposed method is shown to give a reasonable assessment of the flood-resistant capacity of bridges with scoured pile foundations. [ABSTRACT FROM AUTHOR]

This paper presents a case study on monitoring bridge performance under an extreme rainfall event, Typhoon Morakot, which invaded Taiwan on August 8, 2009. An advanced monitoring system was designed in an attempt to improve the efficiency of performance monitoring of bridge substructures during natural hazards by synchronizing various instrumentations, including accelerometers and inclinometers. It successfully recorded the performance of the Shi-Tzou Bridge during Morakot. Progress of this study provides not only verification of the developed intelligent monitoring system but also of the valuable performance data for engineers to access bridge performance under scour and floods conditions. [ABSTRACT FROM AUTHOR]

A 3-story building with a mat foundation consisting of a slab on a grid of grade beams performed poorly on clay soil. Cracking of the slab became progressively worse as a result of the incorrect design and fluctuations in the groundwater pressure under the foundation. The cyclic presence and absence of water rusted the steel reinforcement, and the sulfates in the clay soil caused formation of ettringite in the concrete. Plastic hinges formed in the slab and settlements occurred, causing damage to the beams. The situation is still in progress and may lead to the collapse of the structure under normal service conditions. The geotechnical and structural investigations performed to survey and assess the aforementioned problems are described in this paper. The causes and the consequences of the detected anomalies are analyzed, and a prediction of potential future structural problems is provided. A strengthening procedure is proposed, and an estimate of the cost to realize it is provided. Recommendations are offered to help avoid the problem in new constructions. [ABSTRACT FROM AUTHOR]

Many of the older bridges in the United States have no original contract documents available, and about 26,000 bridges that are rated as scour critical have unknown foundation conditions. Thus, no information is available regarding the type, depth, geometry, or material of these scour critical bridge foundations. The unknown bridge foundations pose a significant problem to bridge owners because of safety concerns. This paper presents the determination of an unknown bridge foundation depth at Forth Worth, Texas. The bridge was supported by driven steel H-piles. Three nondestructive testing (NDT) techniques were utilized: (1) the parallel seismic (PS) method, (2) the sonic echo (SE) method, and (3) resistivity imaging (RI). The main objective of this present study was to compare the suitability of NDT techniques to determine the unknown bridge foundation depth. Based on the field test results, both PS and RI methods provided foundation depth close to actual foundation depth. However, the SE method was determined to be unsuitable for determining the unknown steel H-pile depth. [ABSTRACT FROM AUTHOR]

This article discusses a combined analytical and experimental study on the nonlinear seismic performance of two Guastavino-style masonry domes located in the United States. The seismic performance of these masonry domes is simulated with nonlinear finite-element (FE) models. To support the assumptions and decisions established during the development of the FE models, the vibration response of the domes is measured on-site and systematically compared against the numerical model predictions. Linear FE models are developed that are in close agreement with the measured natural frequencies and in visual agreement with the measured mode shapes. Next, these linear models are extended into the nonlinear range by incorporating the Drucker-Prager damage criterion. Finally, nonlinear FE models are used to assess the performance of these two domes under seismic loadings obtained from the 1940 El Centro earthquake acceleration records. The predicted displacements and internal tensile stress levels are used to make inferences about the potential behavior of these two buildings under the selected earthquake load. [ABSTRACT FROM AUTHOR]

This paper describes an evaluation of the lateral load-resisting system of an existing monolithic, cast-in-place, reinforced concrete (RC) stadium structure completed in the early 1930s. A major renovation/expansion of the stadium completed in the 1990s included modifications of some of the original exterior infill masonry wall, including removal of masonry and enlargement of existing openings. A preliminary study raised concerns about the impact of these modifications on the lateral load resistance of the stadium structure. A new study, which consisted of an evaluation of the structure's performance using in situ lateral load testing of the structure, numerical analyses, and monitoring of the actual stadium-sway movements during football games, was undertaken in 2006 to determine the adequacy of the lateral load resisting system of the stadium. The results of this study, which are reported in this paper, demonstrate that the masonry modifications made during the renovations/expansion of the stadium did not impair the structure's resistance to code-prescribed lateral loads and that no major structural repairs were required. [ABSTRACT FROM AUTHOR]

To investigate the behavior of X-section cast-in-place concrete piles (XCC pile), a series of static load tests for piled foundation are conducted on the basis of a soft soil reinforcement engineering for a sewage treatment plant in the north of Nanjing, China. The testing results are presented in load-settlement curves, pile-soil stress ratios, distributions of skin friction (side friction) and axial force, and load-sharing between side resistance and end-bearing capacity. Comparative analysis between an XCC pile and a circular section concrete pile (circular pile) with the same cross-sectional area indicates that the XCC pile with its increased perimeter can improve the vertical-bearing capacity by 20% because of the larger skin friction. Also, the XCC pile shows increasing pile-soil stress ratio and reduces settlement. The existing design standards for traditional piles can be referenced by the XCC pile composite foundation, because the axial force and skin friction distribution are the same as those of the traditional pile. It has been found that pile spacing is an important factor for XCC piles, and the XCC pile should be considered as a special friction pile because of high skin friction sharing. Above all, the XCC pile can significantly increase ground-bearing capacity. [ABSTRACT FROM AUTHOR]

The construction process can greatly affect a concrete pile's structural performance. Poor decisions concerning a pile's foundation may result in these important structural elements being unsafe so that strengthening interventions may be needed in the future. In extreme cases, the structure may even collapse. The choice of the most suitable construction process is usually a matter for the company constructing the piles and tends to be based either on previous experience or simply on the equipment available at the time. The parameterization model described herein has been devised to induce good construction practices. It includes several factors related to each construction process, and it could influence the structural behavior and durability of concrete pile foundations. The software application combines the input data from a given construction works with a database whose decision parameters are defined. It has been customized for Portugal and is based on expert knowledge acquired from some of its largest construction firms. It gives the most suitable construction process as the output plus a list of reasons for the decision. It also establishes relationships between the result and a second database that compiles the costs and the duration of the selected process, which are essential data at the predesign stage. [ABSTRACT FROM AUTHOR]

Construction on expansive soils is challenging and thus prone to some problems and litigation. The engineering community makes extensive use of local experience and empirical procedures to address these problems. Although there has been extensive study of expansive soils and foundations on expansive soils, data related to performance of residential structures are limited in general and limited in the Phoenix area, in particular. In this study, an overview of the Phoenix Valley, Arizona, geotechnical practice and foundation performance related to residential structures on expansive clays, was developed through surveys and interviews with geotechnical engineers, structural engineers, and homebuilders. Using data obtained from files of Phoenix area geotechnical firms and government agencies, the existing Natural Resource Conservation Service map showing expansive soil locations throughout the Phoenix region was updated through the use of correlation developed in this study relating expansion index to common soil index properties such as Atterberg limits and percent passing the No. 200 sieve. Files of forensic investigations linked to expansive soil regions were made available for this study by several geotechnical engineering firms, and Phoenix Valley areas where forensic investigations have been identified, were mapped for comparison to regions identified in the updated map as having expansive soils. Comparison of the forensic investigation map to the updated map of expansive clay locations revealed that most of the forensic investigations were in regions identified with clays labeled as high to moderately high expansion potential, with a few forensic investigations in regions of medium expansion potential. Finally, unsaturated flow analyses were conducted for an Arizona expansive clay profile for two very different landscaped conditions of well-irrigated turf and desert landscape. The results of the numerical analyses were consistent with the reported observations and modes of failure identified through the surveys and interviews conducted with engineering and homebuilder professionals, including the finding that site drainage was found to be extremely important to good foundation performance, regardless of the type of landscape selected. [ABSTRACT FROM AUTHOR]

Field measurements of foundation movements in central Mississippi have revealed design issues involving expansive soils. At one building, field measurements of the first floor slab at 14 locations show that heaving occurred at a steady rate during part of an extensive drought. The steady rate was maintained throughout the final 21.5 months of a 23.5-month study period following a record drought that occurred at the beginning of the study. The average change in the movement rate was 2.9 mm (0.11 in.) per year over the last 21.5 months. Median movement rates for all the pins varied from 25 mm (0.98 in.) per year to 1.8 mm (0.07 in.) per year excluding the measurements made during the first part of the drought. Elevation surveys at another facility show how the rate of heave is influenced by geologic variations. These surveys also show how the depth of clay (from the surface) influenced heave and how differential movements of a structure are produced from these variations in geology. Design procedures for kind of movement are discussed. [ABSTRACT FROM AUTHOR]

Construction of buildings using a slab on grade and belled drilled piers to support column loads in central Mississippi has performed poorly. Similar buildings where the first floor was poured on 15.2 cm (6 in.) cardboard box forms have not fared much better. The first floor of this building was a slab on grade that was dowelled to a grid of grade beams. The grade beams were dowelled to drilled piers. The top of the expansive Yazoo clay varied from 1.8 to 3.66 m (5.9-12 ft) deep. High swell pressures developed under the slab and began to lift the building. A frame analysis showed that foundation movements were significantly changing the stresses of the structural steel frame. About half of the drilled piers of the building were found to be damaged near the connection with the grade beam. Two piers had separations of 10.2 and 8.9 cm (4 and 3.5 in.). During the foundation repair, the building frame was releveled and eight damaged piers were replaced. Recommendations to reduce the risk of this kind of damage were made. [ABSTRACT FROM AUTHOR]

This paper will focus on the legal liability issues facing the professional engineer engaged in the design and construction administration of facilities built on expansive soils. These legal liability issues will be discussed from the perspectives of the geotechnical, civil, and structural engineer to alert those professionals to the legal ramifications of their daily activities. By focusing on these legal aspects facing the engineers that are involved in the process of building on expansive soils, hopefully litigation can be avoided or successfully defended. Attention to the legal ramifications of engineering is mandated by today's litigious environment in the construction industry, especially when designing and administering the construction of facilities built on expansive soils. [ABSTRACT FROM AUTHOR]

This paper examines the background, history, and results of multiple investigations associated with pyrite-based expansive soils spanning almost 40 years in conjunction with a private elementary school located in western Pennsylvania. The school was initially designed in 1960. Original construction was completed in September 1961 and the first signs of distress, which were primarily related to slab heave, were reported in early 1962. One wing of the school, a 1965 classroom addition (1965 addition) with different structural and foundation systems, did not experience any expansive soil-related damages and served as a valuable comparison throughout multiple subsequent investigations. Pyritic soil material in the subgrade in conjunction with oxygen-rich groundwater was determined to be the cause of soil movement and building distress. Expansive soil-related problems at the school continued for decades despite an investigation, civil court action, and judgment in the late 1960s followed by a remediation program in the 1970s and 1980s. Following a second round of investigations and litigation in the late 1990s, all of the original classroom, office, and gymnasium building sections, with the exception of the 1965 addition, were demolished in late 2000 and early 2001 based on safety concerns and economic evaluation. Investigation and monitoring to confirm subgrade conditions continued throughout the demolition process. As a part of this paper, the history of this case dating back to one of the early identifications of pyrite as an expansive element of concern in building construction, including one of the earliest comprehensive identifications of the complete chemical-microbiological oxidation process is presented. The initial 1960s investigation and conclusions are identified as well as the series of engineering, procedural, and construction errors that took place during and after the first remediation process that led to ongoing soil expansion and structural damage, including misguided actions and misunderstandings that complicated and delayed a final resolution in this case. Today, the industry is more familiar with the potential for pyrite-related construction problems, nevertheless, the paper incorporates lessons learned for avoiding problems and in particular, the procedural failures that led to the eventual need to abandon and demolish the school facility. [ABSTRACT FROM AUTHOR]

The Milwaukee City Hall was built between 1893 and 1898 and is located in downtown Milwaukee, one block east of the Milwaukee River. The 300 ft(91.4 m) long building, nine stories high over its main portion, is a trapezoid in plan. On the south side, there is a 393 ft(119.8 m) tall South Tower located above the main entrance to the building. On three sides, the South Tower rises from the street level to the 13th level and the roof above, and on the north side, it is connected to the rest of the building up to the ninth floor. The South Tower is a hybrid steel and masonry structure consisting of masonry perimeter walls and a central core, four-sided steel truss supporting the floors and roof. The building is a perimeter-load-bearing masonry structure supported on wood piles. The city of Milwaukee had been aware of distress, in the form of cracks and loose masonry, in the South Tower for a number of decades. In 2002, the city took action to investigate the causes and significance of distress, and to develop a repair program. The scope of our work included review of the available structural drawings and documents, inspection of the tower, measurement and monitoring of movements, monitoring of thermal response, structural analyses of the hybrid steel and masonry structure, and development of repair recommendations. The repair program presently is under construction. This paper describes the monitoring program, analyses of the causes for distress, and the implemented repair concepts for the observed distress in the South Tower of the Milwaukee City Hall. [ABSTRACT FROM AUTHOR]

This paper first describes the current state of analysis for the response of unreinforced concrete masonry walls subjected to lateral uniform pressure. The formulation is based on the initial elastic response, the subsequent initiation of cracks and the nonlinear rocking response, and the eventual large displacement and potential collapse. The necessary equations are developed for these phases in the form of a resistance function. The paper then incorporates membrane retrofit materials to strengthen the wall’s resistance to lateral pressure, and develops the necessary resistance function equations. In blast tests, membrane retrofit unreinforced masonry walls have experienced severe cracking and large displacements without collapse. This is of high interest to the Department of Defense, the protection of diplomatic facilities, and the construction industry impacted by hurricanes and other high wind events. The paper concludes with examples that demonstrate application of membrane retrofits indeed increase the resistance of the wall to lateral pressure. [ABSTRACT FROM AUTHOR]

A three-story school supported by shallow foundations was affected by an adjacent 12.2-m-deep excavation in soft clay in which the excavation support system was a 0.9-m-wide secant pile wall braced by both cross-lot struts and tiebacks. The school is a reinforced concrete frame structure with exterior reinforced concrete foundation walls. This paper summarizes the conditions at the site and presents correlations among construction activities, measured deformations and distortions, and attendant damage in the school. The lateral ground movements associated with the excavation were monitored with four inclinometers placed around the school. The building movements were monitored with optical survey points established on interior columns, exterior walls and on the roof, and with tiltmeters installed on the exterior foundation walls. The damage to the school mainly consisted of 300 to 500-mm-long hairline cracks in nonload bearing walls. Only a few cracks had widths greater than 6 mm. The school deformed such that the portion closest to the excavation sagged and the remainder hogged. Damage was first observed in the area of sagging when angular distortions reached 1/940 and the excavation was approximately 5.5-m deep. Angular distortions as large as 1/300 were observed at the end of the project. The data suggest that angular distortions had to be less than 1/1000 to preclude any damage to the school. [ABSTRACT FROM AUTHOR]

The impulse response test is a nondestructive evaluation technique commonly used for quality control of driven concrete piles and drilled shafts where the pile heads are accessible. When evaluating existing foundations, the presence of a pile cap or other structure makes the pile heads inaccessible and introduces uncertainties in the interpretation of impulse response results. A test section was constructed at the National Geotechnical Experimentation Site (NGES) at Northwestern University to examine the applicability of nondestructive testing methods in evaluating deep foundations under inaccessible-head conditions. This paper focuses on the results of impulse response tests conducted atop the three pile caps at the NGES. Based on field experimentation and numerical simulations, a frequency was determined below which the impulse response test could be used for inaccessible-head conditions. This cutoff frequency primarily depends upon the geometry of the pile cap and pile. A case study is presented that describes impulse response tests obtained on a number of drilled shafts both after the shaft was constructed and after grade beams and walls were built. The results of these tests also follow the trends observed in the NGES tests related to cutoff frequency. [ABSTRACT FROM AUTHOR]

Describes the causes of distress to the foundation and slab of an old post office building, and discusses several remedial options. Soil condition; Site geology and field explorations; Test boring and hand auger boring location plan; Subsurface conditions in the vicinity of the distressed area.

The behavior of residential structures subjected to large ground movements was evaluated by observing the response of six test foundations constructed over an advancing longwall mine panel. The foundations were subjected to both horizontal and vertical movements, with the induced curvature from the vertical movements being the primary damage mechanism. A plain concrete footing experienced significant damage, with cracks up to 18 mm in width. Both posttensioning and the use of minimal standard reinforcing were effective at controlling foundation damage, with the standard reinforcing being much more economical. Reinforcing amounts only sufficient to insure the yield moment is greater than the cracking moment are necessary. Additional measures may be necessary to provide adequate stiffness for preventing superstructure damage. [ABSTRACT FROM AUTHOR]

Nondestructive testing (NDT) for the evaluation of deep foundations has been practiced for more than a quarter of a century, usually on new construction projects. It is not always realized that the performance evaluation of older, deep foundations under existing structures can be enhanced by nondestructive testing. The NDT techniques currently available for this objective are described and critically reviewed in this paper. Case histories illustrating the use of different methods to inspect existing piles, drilled shafts, and caissons are presented. Most of these NDT methods are applied in Europe and East Asia, and the present limited use of small-strain nondestructive testing in the North American deep foundation industry is discussed. It is concluded that the methods described in this paper could be usefully employed more often; their limited use is mainly a result of unfamiliarity with the tests and a lack of awareness of their potential by the general engineering community. [ABSTRACT FROM AUTHOR]

Discusses the behavior of residential test foundations subjected to settlement from longwall mining. Effects of large ground movements; Fill settlement; Soil expansion; Bending and twisting curvature of the concrete footing.

Describes the damages to the anchor bolt connection between the concrete foundation and the wood sill plate caused by the 1992 earthquake at Big Bear Lake in San Bernardino County, California. Cause of depletion of shear capacity of the connection; Persons who are responsible for installation; Observations about tie-down anchors.

The article enumerates recommendations for minimizing damage to adjacent building during the process of constructing a new building. The suggestions are divided into three phases. They are the investigation, design and construction phases. Under the investigation phase, the article recommends that test pits be made to determine the characters, depth and condition of the adjacent foundations. Meanwhile in the design phase, it advises considering alternative foundation systems that minimize the probability of damage. Under the construction phase, it suggest insisting on a preconstruction conference, which should include the excavator, the underpinning contractor, the underpinning engineer and the inspecting engineer.