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The need for constructing a shallow or deep foundation (e.g. piles) in a mechanically stabilized earth (MSE) wall for superstructure support has increased. However, the performance of laterally loaded piles within the MSE wall and their interaction with soil and reinforcement are not fully understood. Limited full-scale tests and numerical studies have been conducted to evaluate the behavior of laterally-loaded piles within MSE walls. In this study, thirteen reduced-scale model tests were performed to investigate the effects of changing the wall configuration (wall height, and reinforcement spacing and length) and the pile location on the performance of the pile-MSE wall system under static lateral loads. This experimental study found that the piles in high walls could develop larger maximum compressive and tensile strains. Low walls resulted in larger wall facing deflections and maximum tensile strains in the geogrid reinforcement. Small reinforcement spacing and long reinforcement length resulted in higher pile lateral load capacities, smaller wall facing deflections, and smaller reinforcement tensile strains. The pile offset from the back of the wall facing is a critical factor that affected the pile capacity, the wall facing deflection, the reinforcement tensile strain, and the lateral earth pressure distribution behind the wall facing.

The present study deals with the assessment of surcharge induced consolidation effect on the shear strength of clayey soil and the pile capacity. The study was performed at a construction site located near the coastal area of Tamil Nadu, India. A series of laboratory tests were performed on the disturbed and undisturbed soil samples collected from the site after doing few in-situ tests. The pile capacity was estimated as per the Indian Standards using the properties of soil assessed from the geotechnical investigation and compared with that of field load test on pile. The bored piles were cast upto a depth of 16 m which pass through clayey soil with soft to hard consistency and rest on very dense sandy soil layer. Due to very low subgrade reaction modulus of top soil layer, the lateral capacity of 450 mm diameter pile tested was lesser than the designed. Hence, the design was revised with the 600 mm diameter pile. From the detailed load test program on the 600 mm diameter piles during fixed interval of time, it was found that the site development by 2 to 3 m earth filling induced the consolidation and improved the shear strength of the soil upto a depth of 5 m. The vertical and lateral load capacity of pile was also improved to a maximum of 15% and 70%, respectively after 2 years. The results of the investigation proved the importance of time-dependent behaviour study on the pile capacity assessment.

Very limited studies have investigated the behavior of laterally loaded pile group systems. Accurate prediction of load-displacement response is essential in a pile group to produce a safe and economical design. The nonlinear soil-pile interactive behavior is commonly modeled by p-y curves. The p-y curve of a single pile in a pile group system is modified using a specific p-multiplier for each row of the piles to obtain group reduction factor (Pm) and consider the effects of a pile group. This paper experimentally and numerically investigates the effects of various parameters on the lateral response of piles and p-multiplier in a pile group. Small-scale tests of laterally loaded piles were performed, and a three-dimensional finite element model was validated based on the experimental load-displacement curves. The soil was modeled as an elastic-perfectly plastic material using the modified Mohr-Coulomb constitutive model. The validated model was then used to run parametric studies to evaluate the influence of factors including pile spacing (S), group arrangement, and lateral load combination. The results indicated that the calculated values of Pm for one-way lateral loads at S/D = 3 (S: spacing, D: pile diameter) were close to the values recommended by bridge design specification, AASHTO. However, AASHTO underestimated the group reduction factors and lateral resistance for two-way or angular lateral loads.

Soil replacement technique is the simplest and oldest way in improving the soft soil under the shallow foundations. The process started by taking or removing the un-wanted problematic part of soils and replacing it with other efficient materials. Therefore, this study conducted to analyse on the soft soil replacement using Lightweight Expanded Clay Aggregate (LECA) as a filling material instead of common aggregate. LECA has been widely used in geotechnical application as the materials were successfully recognized in minimising the dead loads by more than half. The settlement magnitude of treated soft soil with LECA replacement was analysed through finite element method by using PLAXIS 2D commercial software. The prediction graph for various internal friction angle has been developed for settlement estimation The graph was then validated using developed Settlement Prediction Model, analytical equations, and numerical analysis. Another finding from this study is a decrease in the magnitude of the settlement as the internal friction angle of LECA increases.

The Linked Column Frame (LCF) structural system is comprised of moment-resisting frames as the primary gravity load-carrying system and a combination of closely-spaced dual columns interconnected with link beams acting together with the moment-resisting frames as the lateral load resisting system. In this system, the link beams are designed to provide ductility and deform plastically. As the damages are concentrated to the links thus, the LCF rapidly returns to occupancy design performance while retaining architectural privileges of the non-braced steel frames. In this study, 3, 6, and 9-story frames equipped with LCF and resting on soil type II and IV are subjected to seven near and far-field earthquake records. These structures are designed based on the plan of SAC buildings using SAP2000, and then, nonlinear time-history analyses were carried. The results indicate that maximum roof drift of the structures on stiff soil (type II) has been insignificantly affected under both near and far-field earthquakes. In soft soils (type IV), drifts values increase by 6.85%, subject to both far and near-field earthquakes. Moreover, in contrast to the stiff soil, roof acceleration has decreased more when the structure is on soft soil, nearly 6.12%. The result of maximum inter-story drift ratios of the structures founded on soil type II illustrates that under an average of near-field earthquakes, drift ratios of 3 and 6-story structures have increased by 3.2%. On the other hand, the 9-story structure has encountered a decrease of 5.17%. Under an average of near-field earthquakes in soil type IV, a drift ratio of 3 and 6 and 9-story structures has grown to 5.11 and 11.2%, respectively, compared to the fixed-base models. In far-field earthquakes, drift values of 3 and 6-story LCF were reduced by 6.2%, and the 9-story structure has experienced an increase of 8.79%.

The article attempts to assess the changes in the properties of the soil backfill on the basis of studies carried out on the soil compaction indicator for a buried flexible steel structure located in a section of the Pan-European railway line. Initial tests on soil compaction showed that the backfilling does not meet the standard for railway structures. On this basis, it was decided to conduct additional studies taking into account the probability of compacting the soil during the operation of the structure. In order to verify any changes, the compaction indicator tests were repeated after 7 months of use under intensive railway load. On this basis, it can to be stated that there is relationship between the impact of a service load and the parameters of a soil backfill over time. As a result of the intense exploitation of a structure, an increase in the soil compaction index even up to 6.0% (average 2.5%) occurs.

The distress of asphalt pavements on horizontal curves can be relatively higher because of the lateral load transfer and the increase in lateral forces on vehicles during their cornering manoeuvre....

Although piles are elements designed primarily to support vertical loads, They are subjected to horizontal loads by serval sources such as earthquake, wind, impact loads and lateral earth pressure. Large number of studies have been carried out to investigate the effect of different parameters on the behavior of piles. These parameters are summarized as i) effect of pile diameter, ii) angle of the pile with the vertical, iii) piles slenderness ratio and soil type. In the present study an experimental program was carried out to identify the deflection of vertical and inclined piles subjected to a lateral force in cohesive soil. The experimental program comprised pile lateral load tests performed on model of single pile driven in cohesive soil. Using the experimental model results, relations were utilized to estimate the lateral deflection of piles.

This paper investigates the lateral loading of a single pile with a necking defect under different conditions in sandy soil. The behavior of the pile was studied by introducing necking defects to a model pile and changing the position of the defect, the length of the defect, the cross-sectional area of the defect, the relative denseness of the soil medium around the pile, and the ratio of the embedded length to diameter of the pile. Model experiments were carried out at 1g in a laboratory using a test tank with sandy soil and a scaled model pile. The lateral load corresponding to a displacement of 20% of the diameter of the pile was taken as the ultimate lateral load. The lateral load-carrying capacity of the defective pile was observed for the different pile configurations and compared with that of the intact (nondefective) pile. It was found that the ultimate lateral capacity of the pile was reduced by the presence of a necking defect along the pile. Additionally, it was observed that the lateral capacity of the pile was greatly reduced when the necking defect was in the top portion of the pile and less so when the defect was in the bottom portion of the pile. The capacity of the pile depended on the length of the defect, the position of the defect, the cross-sectional area of the defect, the relative denseness of the soil, and the ratio of the embedded length to diameter of the pile.

Energy pile is a deep foundation that combines two functions, transferring structural loads to the soil and serving buildings thermal needs. It is an innovative technology that also provides cost savings and environmental protection by reducing fossil energy utilization. In this review study, thermal changes due to heating and cooling cycles that significantly affect the load magnitude and distribution throughout the pile, especially the shear stress and axial load, are discussed. Also, a deep discussion is presented on the current development and mechanical behavior of energy piles. Finally, the essential factors that have the main effect of changing the thermal properties of soil are reported.

To investigate the behavior of piles and the performance of the mechanically stabilized earth (MSE) walls under static and cyclic lateral loading, six reduced-scale model tests of single and group piles within the MSE walls were conducted inside a test box. In the single pile tests, a hollow aluminum tube as a pile was placed at a distance of 2D or 4D (D is pile diameter) behind the wall facing, while in the group pile tests, the piles were only placed at the distance of 2D with a spacing of 3.3D between the piles. The piles were subjected to static lateral loading only and cyclic lateral loading followed by static loading until failure. The test results showed that the lateral load capacity of each pile in the group pile test was approximately 60% that of the single pile, while the wall facing displacements and the geogrid strains in the group pile test were larger than those in the single pile test. The lateral pile capacity, the wall facing displacement, the strain in the geogrid, and the lateral earth pressure behind the wall facing in the static and cyclic loading tests were evaluated at the pile head displacement equal to 20%D.

Raker piles are used more often in combination with vertical piles in a group where the lateral load per pile overshoots the value suitable for vertical piles. Under lateral loads, the behaviour of such group is generally different from that of a vertical pile group due to interaction of raker piles, resulting in the increase of the pile group capacity. A series of laboratory experiments have been carried out with Aluminium pipe pile of outer diameter 25.4 mm and thickness 1 mm in which the soil medium is of clean river sand. The lateral load tests were conducted in driven vertical and vertical–raker pile group configurations (two, three and four) in which raker piles were inclined at angle of 15o from vertical in different soil conditions namely loose sand (relative density, Dr = 30%), medium dense sand (Dr = 45%), dense sand (Dr = 70%). Based on these tests, the group efficiency for different soil conditions and the maximum bending moment were arrived. Based on the experimental results, a non-dimensional design chart has been developed for single pile, vertical and raker pile groups. This study establishes that the effectiveness of lateral load capacity of pile groups increases rapidly up to 50% of relative density of sand beyond which the increase was very minimal. The front raker pile group was efficient to carry lateral load because it resists more lateral load and bending moment than vertical and rear raker pile group configurations. The results demonstrate that the maximum bending moment occurs at a depth of 8D–10D (D—diameter of the pile) for all vertical pile group configurations and 10D–11D for raker pile group configurations.

Experimental and numerical studies are carried out to explore the lateral load and moment resistance capacities of the monopile-friction wheel hybrid foundation in soft-over-stiff soil deposit. Mod...

Wood is preferred as building material in earthquake zones thanks to its light-weight. In countries with high seismic activity, wooden construction systems are required to be resistant to lateral and vertical loads. In traditional architecture, lateral load resistance is ensured with filled and unfilled walls which are strengthened with braces. In present day lateral load resistance is ensured with wooden shear walls formed by sheathings covered on the wall frame. Wooden shear walls may contain openings such as windows, doors and service channels. These types of openings reduce rigidity in wooden shear walls. The opening ratio, opening location, sheathing thickness and connection types have an impact on the lateral load bearing capacity of shear walls. This study investigates the use of two types of wooden shear walls with different-layout openings which were modelled with plywood sheathing material. For the purposes of this study, lateral load bearing capacities were calculated for both types of sheathing material of different thicknesses. The results are presented in tables by comparing the calculated capacity increase to the increase in weight.

Granular columns are widely used to enhance the bearing capacity of weak soil. The filling material of columns is generally stone, gravel or sand. The use of industrial wastes such as steel slag in...

Pile is the form of deep foundation some time may be applying as a condition of inclined loading. There are limited experimental studies in existence on the performance of vertical piles exposed to inclined loads. In this paper, a static inclined load with four angles applied load varying (i.e., 0,15, 30, and 45 degrees) from the horizontal axis of the pile are used to the comparison of behavior for pile group as a three configurations 2x2, 2x3, and 3x2 in sandy soil. The experimental works include a soil tank and several of tools used to achieve the objective of this study. It can be seen that the pile group is influenced by the angle of inclination of applying load, furthermore the results displays that the increase in spacing between pile cause decrease lateral movement under the similar angle of inclination of load applied. The performing of each models better-quality using S/D=7, this is attributable to reduce the interface of pile-soil-pile for the group. Groups 2x3 showing resistance and have bearing capacity to the lateral displacement from other groups about 40% for group 2x2 and about 50% for group 3x2. Conclusion The inclination angle for applied load influences on the responses of laterally displacement. The bearing capacity of pile group are increasing with increase the inclination angles and become near to the vertical axis and leads to less displacement of the pile head. When spacing of pile increases, lateral deflection decreases in the similar load applied. Also, the difference caused by spacing of pile can be evidently noticed in all piles and rows, which is attributable to the influence of overlap among the pile-soil-pile in the group. The configuration of pile group creates variations in ultimate resistance of soil for similar quantity of lateral load. The quantities of resisting load for the first trailing row considerably more than the quantities detected from the leading row. The group (2x3) showing more than (3x2) due to the increasing number of piles in the first trailing row.

The bearing capacity of circular pile has been widely treated considering the soil as a homogeneous material. While the soil properties change randomly, which pushed us to use probabilistic analysi...

The analysis of laterally loaded pile is complex due to its site specific behaviour. Whereas most of the analytical methods provides only a generalized solution to it. Behaviour of piles in clay depends on site specific factors like subsoil condition, type of super-structure and the load transfer from it, construction duration and ground improvement process. The present study deals with the assessment of lateral load behaviour of pile based on the results of conventional and instrumented field load tests. The pile was designed based on the results of laboratory and field geotechnical investigations. The diameter and depth of bored cast in-situ pile were fixed as 600 mm and 16 m from the natural ground level respectively. The deflection profile obtained using inclinometer for various lateral loads on piles tested during different phases of site development were analyzed. The pile bending moment, shear force and soil reaction profile were established from the inclinometer data. The results obtained from the experimental data were found to be comparable with that of analytical method. The non-linear lateral load-displacement curves obtained from the load test conducted at different period of consolidation induced by site development process were analyzed. The curves thus obtained were transferred into a non-dimensional kh/khmax versus shear strain curve for the formation of equation explicit to the specific site. A site specific equation was proposed for the estimation of lateral load-displacement curve with respect to degree of consolidation of the surrounding soil subjected to surcharge load induced by the site development process.

This paper describes the main features related to lateral displacements with depth after successive lateral loading–unloading cycles applied to the top of reinforced-concrete flexible bored piles embedded in naturally bonded residual soil. The bored piles under study have a cylindrical shape, with 0.40-m in diameter and 8.0-m in length. Both bored piles types (P1 and P2) include an embedded steel pipe section in their center as longitudinal steel reinforcements: pile type P1 has another 16 steel rods as steel reinforcement to concrete while pile type P2 has no further steel reinforcement. Pile type P1 has three times as much stiffness (EI) and four and a half times the plastic moment (My) than pile type P2. A similar load–displacement performance was observed at initial loads as for small displacements of both piles. At this initial loading stage, the response of the reinforced concrete piles is a function of the soil characteristics and of a linear elastic pile deformation. During this stage, piles can even be understood as probes for evaluating soil reactions. For larger horizontal displacements, after the concrete section starts undergoing large deformations, approaching the ultimate bending moment, pile behavior and consequently the load–displacement relation starts to diverge for both piles. For pile P1 the values of relevant lateral displacements are extended to about 2.5-m in depth, while for pile P2 lateral displacements are mostly constrained to about 2.0-m in depth. Measurements of horizontal displacements of pile P1 against depth recorded with a slope indicator show that, after unloading, lateral loads at distinct stages (small and near failure loads), exhibits a much higher elastic phase of the system response. An analytical fitting model of soil reaction is proposed based on the measured displacements from slope indicator. The integration of a continuous model proposed for the soil reaction agrees fairly well with the measured displacements up to moments close to plastic limit. Results of load–displacement show that the stiffer pile (P1) was able to mobilize twice as much lateral load compared to pile P2 for a service limit displacement of about 20 mm. The paper shows results that enable the isolation of the structural variable through real scale pile load tests, thus granting understanding of its importance and enabling its quantitative visualization in examples of piles embedded in residual soil sites.

Piled raft foundations have been recognized as the most economical foundation systems, able to deal with heavy structural loads, as the bearing capacity of both the raft and pile components is considered. Due to the complexity of lateral load sharing between the raft and piles in a piled raft foundation, piles have been commonly designed for the entire lateral loads, which results in inefficient design. Therefore, the exact determination of load bearing proportion of each component, under both vertical and lateral loading and also in different soil types in terms of stiffness, leads to a more economical design. The present study aims to investigate the effect of soil stiffness on the performance of superstructure and foundation during an earthquake, by implementing a 3D finite element modeling. Three types of soil, including loose, medium, and dense sand, have been used to consider changes in the soil stiffness. Examined foundations include two types with 3 × 3 and 4 × 4 pile group arrays. Moreover, in order to take account of the influence of superstructure on the load sharing mechanism of the components, a ten-story building, consisting of moment frames, braces, and rigid floors, has been modeled. A dynamic load is then applied in the form of time history acceleration at the base of the soil mass. The results indicate that with an increase in soil stiffness, in spite of the rise in shear force at the base of the structure (base shear), the participation of the pile group in horizontal load bearing has been reduced (approximately by 50% in loose sand and 30% in dense sand).A similar trend is observed for the horizontal and vertical displacements of the foundation. Furthermore, bending moment and shear force in the pile gradually decrease with increasing soil depth, and their maximum occurs at the pile head.

The bearing behavior of suction caissons supporting offshore wind turbines under two-way cyclic lateral loading and dead load in clay was investigated with consideration of soil strength degradation and adhesive interface friction between caisson walls and heterogeneous clay using the finite-element package ABAQUS. An ABAQUS built-in user subroutine was programmed to calculate the adhesive interface friction between clay and caisson walls. The results of parametric studies showed that the degradation of bearing capacity could be aggravated by the decrease of the aspect ratio. The offset between the rotation point of the soil inside the caisson and the central axis of the caisson increased with the increasing vertical load and number of cycles. The linearly increasing strength profile and adhesive interface led to the formation of an inverted spoon failure zone inside the caisson. The settlement-rotation curves in each cycle moved downwards with increasing number of cycles due to the soil strength degradation.

Mechanical response of buried pipes subjected to vehicle live loads acting on the ground surface has been exhaustively studied in the past decades. However, it remains an open subject especially for cases where the load is not necessarily positioned over the centre of the crown. Simplifications regarding loading transmission based on the theory of elasticity and the lack of soil–pipe interaction in the analyses have been blamed for possible lack of adherence between the predicted and the observed behaviour of such structures. Herein, both numerical and physical modelling were used to capture the important features of the mechanical behaviour of buried pipelines under live moving surface loads. The physical models were tested under modified gravity in a centrifuge, which allowed the calibration of a three-dimensional numerical finite-element model. Three different models were tested in the geotechnical centrifuge, corresponding to three different cover heights: 1D, 1·5D and 2D, where D is the pipe diameter. The results showed that pipe deformations, caused by live vehicle loads applied at distances greater than twice the diameter of the pipe, are negligible. The diametrical deformations did not exceed the 2% limit suggested by regulation associations. The highest value found in this study was 0·2%.

Foundation is the integral part of structures which is taking all the structural loads and uniformly distributing to the underlying soil. Piled raft is a foundation system where the functions of both pile and raft foundations are combined together effectively to work as a single load distributing system. The major advantage of this system is that, it can act as settlement reducer and are proved to be economic that it can be used where a larger structures. In this work, a model study of a piled raft system by conducting a series of tests on the model with varied design parameters of pile, raft and soil condition. The dimensions and parameters of models are 200 mm × 200 mm size raft with pile lengths of 180 mm, 200 mm and 250 mm which are tested on loose and dense states of soil with number of piles of 4 and 9 sets. The vertical load tests were conducted on both piled and unpiled rafts in loose and dense state of soil and the results were compared. From the results, improvement in the bearing capacity and reduction in settlement were observed with increase in the length of piles, number of piles and density of soil. About 32% of increase in load carrying capacity was noted when length of piles compared to the shortest piles and 79% of increase in load capacity for the system when degree of compaction of soil were varied from looser to denser state of foundation soil. Thus from this model study, it was suggesting that the pile raft system with optimised design of pile and raft can improve the efficiency and this foundation system can also be made economical by providing an alternative solution of foundation for heavy buildings.

The light weight concrete has been used most widely in the world for may years and has a very special advantages when compared with the conventional concrete. In this study coarse aggregates are partially replaced with steel cinders, obtained from steel industries. These steel cinders have lower specific gravity and hence the cinder concrete is lighter when compared with the normal concrete and thus reduce the cost of constructions and also the dead load of the structure, which helps in designing heavy structures. The objective of the reseach work is to find the maximum percentage of replacement of steel cinders in concrete and to compare the mechanical properties of the optimum values with the conventional concrete of M20 grade. The coarse aggregate is partially replaced with steel cinders in various percentages say 20%, 40%, 60%, 80% and to full replacement of 100%. The compressive test was conductued for cubes of 150 mm size at various percentage of replacement and was compared with the conventional concrete. It is observed that cinder aggregate concrete with 60% replacement of cinder reached the equal target mean strength as conventaional concrete.

Medium rise R.C framed apartment buildings with storey ranges from 8 to 10 or 12 are becoming popular in metropolitan areas of India. Medium rise R.C framed are provided with shear walls for the lateral load resistance. Frequently the shear walls are provided with openings thus it is necessary to study the effect of those on the storey drift, storey stiffness, and shear and moments and on the stress within the shear walls. A 3-D analysis is carried out for analysis of the shear wall in the building. This study covers the effects of size and locations of these openings. Detailed results have been obtained and useful conclusions are drawn on the basis of this study which will be of use to the practical engineers.

During strong earthquakes, civil structures are subjected to damaging forces. Tall buildings if damaged would threaten the life safety of inhabitants or at least would cease to offer the same level of functions. For this reason, tall buildings should be designed in accordance with the seismic provisions that ensure suitable performance during and aftermath. One of the factors that dominate tall buildings’ design is the dynamic soil-structure interaction (SSI) that differs significantly with the variation of several aspects. Soil type that incorporate the building’s foundations, the height of the building, the type of lateral load resisting system, and many other factors. In this research authors have considered SSI using the direct method (i.e. FEM soil medium) and studied the effect of changing soil type (soft soils and hard soils) on the performance of the tall building under consideration. The building was taken to be 16 stories, wall-framed dual system for seismic loading resistance. Semi-infinite elements from Abaqus (simulia’sAbaqus 6.14) solid element library were used to model the boundaries of soil media. The seismic loading input was El-Centro acceleration time-history record. Results of analysis showed differences between soft soil and hard soil types, especially on the displacements and base shear values.

The piled raft foundation has shown growing applicability in the last two decades as an economic foundation type, where the structural loads are carried partly by the piles and partly by the contact stresses under the raft. The ratio of the load carried by piles to that carried directly by the contact stresses under the raft depends on many factors. Among these factors are the relative rigidity of the raft, the shear strength of the soil under the raft, the shear strength of the soil at the piles tin, the frictional stresses along the piles, and the piles settlement. The investigation of the effect of these factors requires a reliable finite element model that takes into consideration the nonlinear soil behaviour and the interaction between soil, piles, and all. In this article, two 3-D nonlinear (finite element models of piled raft foundation are adopted. In the first model, the interface elements are placed between the piles and soil, as well as between the raft and soil. In the second model, the interface elements are placed between the piles and the soil only and a gap is formed between the raft and the soil (free standing cap). The soil is modeled using Drucker Prager yield criteria while the piles and the raft are treated as a linear elastic material. The proposed models are applied to piled rafts resting on medium clay while the piles are rested on medium dense sand. The results reflect, the interaction among the piles, raft and soil. The study shows the effect of the contact between the soil and the raft on the pile loads and raft moment and deflection.

The conventional foundation design methods consider these loads independently. However, these loads often act together and their independent existence is rare. Finned piles are found to be a better alternative to monopiles in resisting lateral loads. Lateral load carrying capacity of the foundation is highly significant in the case of tall structures. In the present study, the response of finned piles to lateral loads under combined loading conditions has been investigated. Small-scale laboratory model tests were performed on monopiles and finned piles embedded in sand. The studies were carried out by varying the geometric factors such as length, width and area of the fins. From the studies, it was found that the lateral load carrying capacity of the finned piles increases considerably in comparison with monopiles. The tests revealed that the lateral capacity is a function of the surface area of fins. Under combined loading, a logarithmic relationship between the increase in lateral resistance capacity and the surface area of the fins was identified.

Many research efforts have been carried out, in a quest to produce mix design information that will guide the concrete and construction industry on how to achieve different concrete strengths, using the different grades of cement available. This is with a view to arresting the rampant collapse of buildings in Nigeria. The work presented in this paper is the result of investigation carried out to determine effects of changing cement grade, while casting a structural member, on the strength behaviour of the concrete. Two types of cement grades: 32.5 R and 42. 5 R were used for this research. In this investigation, the chemical and physical properties of the cement were determined. Consistency and setting times of mortar specimens from the two cement grades were also determined. Concrete samples made from the two cement grades 32.5 R and 42.5 R were evaluated for workability, density, compressive and tensile strengths at water/cement ratios of 0.40, 0.50 and 0.60. The results showed that the cement grade 42.5 consistently developed higher densities at all the water/cement ratios considered. This may be as a result of unforeseen additional dead load at the design stage, which would now amount to underestimation of dead load and thus design load. The results also showed that at higher water/cement ratios, the cement grade 42.5 R has densities exceeding the 2400 kg/m3 recommended by BS 8110. Furthermore, the concretes produced with cement grades of 32.5 R and 42.5 R have different strength development pattern and developed different 28-day compressive strength. Thus, it can be concluded that the action of changing the cement grade during concreting, for the same structural member is not supported by the national code, and will not result in safe and durable concrete. Keywords: Cement grades, Compressive strength, Density, Portland limestone cement, Tensile strength, Workability

The soil around the pile foundations of offshore wind turbines (OWTs) would suffer from earthquakes which are widely believed to undermine the bearing capacity and serviceability of foundations. Th...

The lateral response of piles embedded in soil is typically analyzed using the Winkler nonlinear springs method. The predictions of “load–displacement” response of the pile group are needed for a safe and economical design. In this method, the soil–pile interaction is modeled by nonlinear p-y curves in a way that the single pile p-y curve is modified using a p-multiplier for each row of piles in the group. The average p-multiplier is called the group reduction factor. Most research has focused on the behavior of laterally loaded single piles, though piles are most frequently used in groups. The present study was conducted to investigate the effects of various parameters, such as the pile spacing, different layouts, and the lateral load angle change as a new parameter, on the lateral response of piles, group efficiency, and p-multiplier factor in the group. Soil is modeled as an elastic–perfectly plastic material using the modified Mohr–Coulomb constitutive model. In addition, the Abaqus 3D model is validated using load–displacement results from laboratory tests of laterally loaded piles embedded in sand. The p-multiplier factor calculated from this study is well comparable with those of the full-scale tests on pile groups. However, based on the results, the calculated values of the p-multiplier factor at S/D = 3 (obtained from interpolation the values of group reduction factor at S/D= 2.5 and S/D = 3.5) are close to those recommended by the AASHTO, especially for 3 × 3 pile group.

A nonlinear analysis framework for laterally loaded piles is presented that is as accurate as equivalent three-dimensional nonlinear finite element analysis, but computationally one order of magnitude faster. The nonlinear behavior of sands and clays are account for by using hyperbolic modulus–reduction relationships. These nonlinear–elastic constitutive models are used to calculate the reduced modulus at different points in the soil based on the soil strains induced by lateral pile displacement. The reduced modulus at different points in the soil domain are spatially integrated to calculate the reduced soil resistance parameters associated with the differential equation governing the lateral pile displacement. The differential equations governing the lateral displacements of pile and soil under equilibrium are obtained by applying the principle of virtual work to a continuum-based pile–soil system. These coupled differential equations are solved using the one-dimensional finite difference method following an iterative algorithm. The accuracy of the analysis is verified against equivalent three-dimensional nonlinear finite element analysis, and the validity of the analysis in predicting the field response is checked by comparisons with multiple pile load test results. Parametric studies are performed to gain insights into the lateral pile response.

To study the mechanism of rockburst and its spatio-temporal evolution criterion, a rockburst simulation experiment was performed on granite specimens, each with a prefabricated circular hole, under different lateral loads. Using micro camera, acoustic emission (AE) system, and infrared thermal imager, the AE characteristics and thermal radiation temperature migration were studied during the rockburst process. Then, the failure mode and damage evolution of the surrounding rock were analyzed. The results demonstrate that increasing the lateral load can first increase and then reduce the bearing capacity of the hole. In this experiment, the hole failure process could be divided into four periods: quiet, particle ejection, stability failure and collapse. Correspondingly, the AE signals evolved from a calm stage, to have intermittent appearance; then, they were continuous with a sudden increase, and finally increased dramatically. The failure of the surrounding rock was mainly tensile failure, while shear failure tended to first increase and then decrease. Meanwhile, damage to the hole increased gradually during the particle ejection period, whereas damage to the rockburst mainly occurred in the stability failure period. The thermal radiation temperature migration exhibited warming in shallow parts, inward expansion, cooling in the shallow parts with free surface heating, inward expansion, a sudden rise in temperature of the rockburst pits, and finally specimen failure. The initial reinforcement support should fully contribute to surface support. Furthermore, an appropriate tensile capacity and good energy absorption capacity should be established in support systems for high-stress roadways.

Existing caisson foundations, utilised for offshore wind turbines, are required to resist significant lateral loads and overturning moments generated by wind and currents. This paper presents an innovative type of foundation, a ‘winged caisson foundation’, to support offshore wind turbines, which has the ability to provide a larger overturning capacity compared with standard caisson designs. Through a series of small-scale experiments at 1g conditions, the competence of the proposed foundations was examined. Different models with various wing sizes and different soil densities were tested in the laboratory under overturning loadings and the results were compared with a standard caisson. The moment–rotation performance of the foundation under both monotonic and cyclic loading was examined to assess the potential benefits of adding wings to caisson foundations. The results showed that there is a significant increase (up to 75%) in overturning capacity provided by the novel foundation, demonstrating its great potential over standard caissons for use in offshore wind turbine foundations.

Rigid piles are widely used as foundations to resist lateral load. A calculation to confirm that the ultimate lateral geotechnical capacity of such piles is not exceeded is required for ultimate limit-state design. Existing (empirical) approaches employed to predict the lateral capacity of a rigid pile in sand assume the net soil pressure is a function of the vertical effective stress and friction angle. However, difficulties in determining the appropriate friction angle(s) make these approaches less useful for practical purposes. A simple alternative approach correlated with the cone penetration test end resistance (qc) is developed in this paper based on ultimate capacities measured in a new series of tests on rigid piles with diameters of 127, 169, 273 and 457 mm and aspect ratios (L/D) between 1·6 and 12. These test results are combined with additional tests reported in the literature to establish a simple formulation for the ultimate net pressure adjacent to a pile in sand. Explicit design equations are also presented for soil profiles with a constant qc value and where qc increases linearly with depth. The proposed equations are seen to provide good estimates of capacities for rigid piles with a wide range of diameters.

Buried gas pipelines are vital assets of natural gas transportation system for every country. Therefore, investigation of their potential failure’s roots is prominent. There are different causes for their failure among which imposed loads are the majority. In this study, considering soil as an elastoplastic material and deriving its constitution equation, a steel gas pipeline was modeled in its critical cross section where it passes under a road. Studying the behavior of the axial stress as maximum stress component and pipeline displacement under live and dead loads, a safe depth of 2 m was found so as to decrease and increase failure probability and safety factors, respectively. This height not only negates live loads, it alleviates the effect of dead loads.

In this study, two-way cyclic lateral loading tests with constant displacement amplitude are performed to investigate the effect of cross section geometry and modulus of elasticity on the behavior of model piles in sand. Various laboratory pile models were tested in a metal test tank equipped with various facilities including cyclic lateral loading system, devices to measure displacement and pressure along the pile, an inverter to adjust or change loading frequency, sand raining system, etc. Different cross section geometries, including square and circular shapes, were used for piles made of polyethylene and polyurethane. A loading frequency of 0.29 Hz and a total number of 145 loading cycles were used for all the tests. Results revealed that in constant displacement amplitude tests, both lateral load resistance of the pile head and stiffness of the pile–soil system increase with an increase in the number of loading cycles; however, the rate of increase gradually decreases. It is shown that these variations may be formulated using a logarithmic relationship, which includes a degradation parameter reflecting rate of these changes. For tests with different pile cross section shapes, dimensions, and moduli of elasticity, the degradation parameter varied from 0.08 to 0.18. The pile head load and stiffness of the pile–soil system at the end of the 145th cycle varied from 1.4 to 1.85 times those of the first cycle for different section shapes, dimensions, and moduli of elasticity.

This paper presents critical assessment of codal provisions to determine lateral stability of a well foundation. A two-dimensional finite element model of soil–well foundation system is developed for this study. The well foundation is modeled as a linear elastic body, whereas the soil as a nonlinear elasto-plastic material which is defined using multi-yield surface plasticity model. Interface between the well foundation and the adjoining soil is defined using constitutive relationships describing relative sliding and separation at the interface. Assumptions considered in the existing codal provisions to determine lateral stability of a well foundation are evaluated in light of the results obtained from the present study. The present study shows that the mechanism of deformation of laterally loaded soil–well foundation system obtained in this study differs from that considered in the existing codal provisions. It is observed that the existing codal provisions overestimate the lateral load capacity of a well foundation.

On November 5, 2015, roughly 32 million m3 of iron mine tailings were accidentally released in the collapse of Fundao dam in Minas Gerais, Brazil. Totaling about 61% of the impoundment’s contents, the spilled tailings buried the town of Bento Rodrigues, claiming the lives of 19 villagers, and causing major environmental concerns. This study presents a comprehensive static liquefaction triggering analysis performed on the failing section of the dam prior to its collapse, with the goal to determine its susceptibility to liquefaction under its ultimate loading condition. The method of analysis implemented accounts for variations in mode of shear, anisotropic consolidation, and lateral load transfer along the failure surface normally encountered in the field. The instability line and flow liquefaction concepts are used in conjunction with in-situ test data to estimate liquefaction triggering and post-liquefaction undrained shear strengths for loose saturated tailings in the dam’s section. These are subsequently applied in iterative limit equilibrium analyses to obtain the factors of safety for liquefaction triggering and flow failure. After convergence in this process, the failing dam’s section was found to be susceptible to static liquefaction flow failure with a factor of safety of 0.56.

This study examines the use of granular soils mixed with tire derived aggregates (TDA) as an underlying soil layer for surface foundations. The benefit of this geotechnical seismic isolation (GSI) scheme is threefold: the seismic force and displacement are significantly reduced; the construction is similar to that of a regular compacted granular fill and the re-use of scrap tires has an assertive environmental impact. These features highlight the rubber/soil mixtures (RSM) as a promising seismic isolation technique for infrastructure and large-scale structures. The seismic isolation capabilities of a rubber-soil foundation layer are investigated, using well defined material properties, and the direct analysis method of the soil-structure system, in the form of a simple oscillator on a soil profile. The influence of the RSM layer on the fundamental variables of the seismic response, namely the base shear and the total drift displacement of the structure on deformable soil, is examined. The structure’s overall stability is studied by means of monotonic lateral load analysis and incremental dynamic analysis, varying the slenderness of the structure and the synthesis of the mixture. The effectiveness and capabilities of the RSM isolation scheme are presented and discussed.

The paper presents results of numerical simulations of the stress distribution and deformations within of foundations of huge monument of Christ The King erected in Świebodzin (Poland) in 2010. It is 3 meters taller than the better known statue of Christ the Redeemer in Rio de Janeiro, standing at 30.1 meters tall without its pedestal. Foundations were built as a system of reinforced concrete columns and slabs which can be classified as a spatial column-slab system. Actual mechanical parameters of the substrate and of the artificial mound made of field stones, sand, gravel and clay were adopted in calculations. The numerical simulations of structural members of foundation and determination of the stress distribution are presented in the article. Monument itself was not included into the model. Instead of it the rigid cantilever was introduced to which resultant forces were applied. Three different stages were distinguished: the initial state after foundation and mound accomplishment, the initial state plus the dead load and the initial state plus the dead load and the wind load. It was assumed that the wind load was taken into account in a quasi-static formulation by applying the equivalent horizontal force and the torque. Stresses and displacements for these three stages were determined by Finite Element Method using Simulia ABAQUS system. It was disclosed what was a contribution of particular parts of foundations in sustaining loads in considered load cases. The state of exertion of structural members of foundations and the soil itself was assessed. It was showed that the column-slab foundations and soils of the mound play important role in taking loads of the statue, spreading them and safe transferring to the undisturbed level of natural soils. According to the numerical simulations results the columns of foundation take as much as 64% of the vertical load (in the most unfavourable load conditions). At the same time soils of the mound take through the side surface of piles about 20 % of the vertical load.

Piled raft is the most desirable foundation option in the recent era for offshore and onshore structures which are often exposed to combined vertical and lateral (V-L) loads. Due to the scarcity of...

In this paper, we propose a three-dimensional finite element model that can simulate the caisson foundation behavior in gravelly soil. The soil model adopts a combination of the porous elastic model and the modified Drucker–Prager/Cap model for simulating the gravelly soil. For avoiding problems in laboratory testing on gravel specimens, a practical approach is proposed to determine and calibrate the parameters of the soil model using results of field geotechnical tests, such as a shear wave velocity profile, strength parameters of direct shear tests, and pressure–displacement curves of vertical and horizontal plate loading tests. The proposed finite element model was applied to simulate in situ lateral load tests on bridge caisson foundations in gravelly soil. Using the calibrated soil model, responses of caisson displacement, caisson head rotation, and soil displacement analyzed were observed to be in agreement with the measured responses. Caisson and surrounding soil responses were also investigated in detail.

The structural response of box culverts to variable soil compressibility condition was studied in this paper. This was made possible by modelling the soil as springs, and varying the spring stiffness which was represented by the modulus of subgrade reaction of the soil. The results showed that the values of maximum bending moments for gravity actions on box culverts increased linearly with modulus of subgrade reaction, but remained within close values. The results also showed good agreement with results from literature for highly compressible soils. However, for incompressible soil condition, results from standard tables in literature were more conservative with about 10% difference for gravity actions, and 21% difference for lateral actions. The term ‘highly compressible’ that was used in literature for manual analysis was discovered to be more valid for lateral load cases than for gravity load cases. Subsequently, the variations of other action effects such as shear force, axial force, torsion, and soil spring settlement with modulus of subgrade reaction were also studied. Keywords: Box Culvert, Modulus of Subgrade Reaction, Soil Settlement, Staad Pro.

One of the major concerns in designing bucket foundations is addressing the effect of the shape of the foundation on deformation. It has not yet been clarified sufficiently how the ultimate load capacity and the deformation up to failure are dependent on the bucket shape, bucket dimensions, loading conditions, and soil properties. Not only for conventional cylindrical bucket foundations, but also for rectangular bucket foundations, in order to adequately design each type of bucket foundation, analytical solutions for the general loadings of both foundations have been urgently needed. In the present paper, analytical solutions are provided by a three-dimensional displacement approach for predicting the deformation up to failure of the soils surrounding cylindrical and rectangular bucket foundations subjected to vertical, lateral, and moment loads in cohesionless soils. The analyses are carried out for nonhomogeneous sandy soils. The lateral stiffness coefficients along the short skirt are presented by extending those along the normal skirt for both cylindrical and rectangular bucket foundations. The lateral yield along the skirt and the compression and shear failures below the base in sand are seen to have a significant influence on the ultimate lateral and moment load capacities of cylindrical and rectangular bucket foundations under vertical loads. Failure envelopes expressed by both ultimate horizontal and moment load capacities under various vertical loads in sand are presented. For cylindrical bucket foundations, as the embedment ratio and vertical load increase, the ultimate lateral and moment load capacities increase. However, for rectangular bucket foundations, the relationships among the ultimate lateral and moment load capacities, vertical load, and embedment ratio are greatly influenced by the breadth ratio. The largest ultimate lateral and moment load capacities among the breadth ratios of rectangular bucket foundations under a certain vertical load depend on the embedment ratio. The ultimate lateral and moment load capacities of square bucket foundations are less than those of cylindrical bucket foundations with the same cross-sectional area. The predicted relationships between the ultimate lateral and moment load capacities and the embedment ratio under various vertical loads are compared with the results obtained from FEM and experiments. The monotonic behavior of the sand surrounding bucket foundations up to failure is elucidated from the relationship between the lateral load and the lateral displacement and that between the moment and the rotation.

Comparative lateral load field tests were conducted on two straight-sided and two belled piers in a natural arid loess sloping ground with an inclination angle of 20° in the western Chinese Loess Plateau. The pier-head displacements, sloping ground surface deformations and soil pressure distributions were measured. The lateral load–displacement curves of the straight-sided and belled piers in the sloping ground generally exhibited the same three-phase non-linear behaviour, and their performances were similar to those of laterally loaded drilled shafts in horizontal ground. The ‘interpreted failure load’ of the laterally loaded piers in sloping ground was obtained using the representative lateral interpretation criteria and their extensions. Compared with the normalised lateral load–displacement curves of the drilled shafts in horizontal ground under drained and undrained lateral loadings, the displacement required to completely mobilise the lateral resistance for piers in sloping ground was much smaller. It was found that the use of belling can cause greater load transfer depths and can effectively mobilise more soil to resist lateral load. In addition, for both straight-sided and belled piers, an additional embedment of the shaft in sloping ground can increase lateral resistance to match the level-ground lateral capacity.

Grouted micropiles are widely used in transmission tower foundations and in situ reinforcement in China. This paper deals with the grouting effect on the lateral performance of grouted micropiles embedded in marine soft clay, especially with an external driving shoe. Full-scale lateral loading tests on both grouted and non-grouted micropiles were conducted. The equivalent diameter of a grouted micropile was determined using the cylindrical cavity expansion method and the empirical value of the equivalent diameter was also calculated. The test results showed that, compared with a non-grouted micropile, the lateral bearing capacity of the grouted micropile was improved by 3·75 times. The empirical equivalent diameter was determined to be about 1·5 times the diameter of the steel pipe used, and this was used to predict lateral load–displacement responses of the grouted micropile.

A hybrid analytical-numerical solution is proposed to solve the problem of a laterally loaded pile with a circular cross-section in multilayered soils. In the pile-soil model, the lateral load is located at the pile head including both lateral force and bending moment. The single pile is considered as a beam on elastic foundation while shear beams model the soil column below the pile toe. The differential equations governing pile deflections are derived based on the energy principles and variational approaches. The differential equations are solved iteratively by using the finite element method that provides results of pile deflection, rotation angle, shear force, and bending moment along the pile and equivalent stiffness of the pile-soil system. The modulus reduction equation is also developed to match the proposed results well to the three-dimensional finite element analyses. Several examples are conducted to validate the proposed method by comparing the analysis results with those of existing analytical solutions, the three-dimensional finite element solutions. Keywords: beam on elastic foundation; finite element method; pile; energy principle; lateral load.