Intermediate Pile Research Articles

Numerical Analysis of Block Type Quay Wall with Piles for Restraining Horizontal Deformation

A two-dimensional numerical analysis was performed on the depth of pile embedment, the magnitude of the residual water level, and the condition of the presence or absence of cap concrete to understand the behavior of the block-type quay wall with piles. The results showed the control effect of the lateral displacement of the quay wall depending on the embedment of the pile. When the piles were not embedded, the lateral displacement of the quay wall increased proportionally as the residual water level difference increased. In contrast, when the piles were embedded into the ground, the control of the lateral displacement of the quay wall was greatly exerted even if the residual water level difference increased. There was little difference in the lateral displacement of the block-type quay wall regardless of the presence or absence of cap concrete. Under the condition where the piles were embedded down to the rubble mound layer, the piles exhibited the rotational behavior seen in the short piles. As the embedment depth of the piles increased, the piles showed the same bending behavior as the intermediate piles. Thus, the piles significantly contribute to the control of lateral displacement in the block-type quay wall with piles.

Effect of sacrificial piles on local scour around complex bridge piers

Sacrificial piles are used to minimize or remediate the local scour around existing bridge supports. This study evaluates the impact of using sacrificial piles on the scour around complex bridge piers. An experimental model is used to simulate nine different scenarios of sacrificial piles. Different numbers, arrangements, and distances of the sacrificial piles are studied. A large diameter sacrificial pile was also considered to evaluate the diameter’s effect. The results show that sacrificial piles are very effective in reducing scour around complex piers. An effective sacrificial piles arrangement should include an intermediate pile aligned with the center line of the complex pier. The scenario of three collinear piles in the transverse direction of the flow gave the best efficiency as it reduced the maximum scour depth by 63 % compared to the base case. On the other side, increasing the diameter of a single sacrificial pile enhanced its efficiency.

Two-dimensional Analysis of the Group Interaction Effects Between End-bearing Piles Embedded in a Rock Mass

This research is a two-dimensional analysis of the interaction effect in a group of piles socketed in a rock mass when studying the end-bearing capacity of the group. This problem was extensively studied for deep foundations in soils, but very little is published about foundations in rock. The study was conducted in 2D to establish the basis and criteria to analyze the problem, as well as understand the main factors and failure mechanisms involved when several piles work together in a foundation. The factors included in the analysis are, among others: the parameters of the rock mass, the pile embedment, and the pile separation. The research highlights shaft resistance as one of the key factors in the interaction. It proves that neglecting shaft resistance changes the interaction influence and the failure mechanism which may not be on the safe side. The research includes an analysis of the failure modes of different pile configurations using the discontinuity layout optimization (DLO) method, by taking advantage of the method’s ability to show the wedge configuration at the failure. The minimum and maximum efficiencies are characterized in terms of the pile separation values, thereby proposing a procedure to obtain the absolute minimum efficiency of the group. A second procedure is also presented for the approximate prediction of the bearing capacity of the pile tip, for a group with a particular number of piles and properties, by considering the contribution of the corner piles and the intermediate piles.

Investigation on the rotational bedding of king piles on the basis of model tests

Rising world trade and the following consolidation of material flows cause a growing need for bigger bulk carriers. Therefore, the quay walls of the harbours need to be adjusted to realize the depth of the channels. Combined sheet pile walls are used to build quay walls. They consist out of up to 45 m long H-shaped beams and Z-shaped intermediate piles. As a result of the loads, which cause normal forces and bending moments, the stability of the slender profiles is endangered, whereby the deflection of the profile head and the embedding in the soil plays an important role. With the introduction of the standards of DIN EN 1993-5:2010-12 [1] in connection with DIN EN 1993-1-1:2010-12 [2] the proofing of combined walls needs to be done under combination of the resistance against flexural buckling and lateral-torsional buckling. For that reason the rotational resistance of the soil must be considered in order to ensure an economical design. The rotational bedding in cohesive soil is different from that in noncohesive soil and was investigated by laboratory tests as well as by numerical simulations. The results of a FOSTA / aif project with the goal of optimizing the stability procedure of combined walls are be presented.

Improved approach of super-long pile group considering multiple interaction under axial load

This work presents an improved approach to consider the effect of any intermediate piles between the two piles in pile groups. Based on the thin ring shear model of concentric cylinder and elastic theory, a multi-pile analysis model under axial load is proposed with full consideration of the mutual reinforcing effect between super-long piles. A theoretical derivation of interaction coefficient and the deformation of super-long pile groups which simultaneously consider the reinforcing effect and the existence of other piles in pile groups was carried out. Example analysis shows that the analytical solution agrees well with the experimental results. In this work, the error between the calculated result of the presented model and the measured value is 25% less than that in the traditional model. The multi-pile model fully analyzes the interaction mode between multiple piles and considers the mutual reinforcing effect among the piles, which makes up for the deficiency in traditional settlement calculation of pile groups. Consequently, the model proposed can accurately reflect the working characteristics of super-long pile groups in actual engineering.

Closed Form Solutions for Predicting Lateral Response of Tripod Suction Pile for Offshore Wind Turbine Foundation

This study presents a simplified analysis technique capable of predicting the dynamic behavior of a tripod suction pile subjected to a horizontal load. The first natural frequency of the system, horizontal displacement, and allowable rotation angle at the pile head were set as target physical quantities in accordance with substructure design requirements. In consideration of the physical characteristics of the tripod suction pile, the analysis was extended to the single pile-multi-pile-tripod-tower part to derive the influence factors. A possible displacement response function that could be applied to the intermediate pile range was also proposed. Thereafter, a detailed design was determined using an integrated load analysis, which included a turbine based on the basic design of simplified analysis method. Furthermore, the dynamic behavior of the offshore wind turbine at each installation stage was predicted using a numerical analysis and measured via field tests. The displacement at the pile head and the predicted value of the first natural frequency of the system were compared using the field-measured and numerical analysis values. The first natural frequency value produced by the simple analysis method showed an error range within 1%, and the displacement at the pile head also satisfied the structural design requirements. Therefore, this method provides a quick and accurate solution to the lateral response of tripod suction piles as foundations for offshore wind turbines.

Risk of failure for the salso river railroad steel bridge

The degradation state of railroad steel bridges is one of the most important and difficult aspects to be interpreted. The use of steel bridges started from 1900, and they are still in service today as railroad bridges. The case study examined was that of a bridge railroad steel bridge having a total length of 112 m and constituted by three isostatic, reticular beams having a Pratt type composition. The substructures (two shoulders and two intermediate piles) are in masonry with a reinforced concrete beam in the upper portion.The structure (steel bridge and piers) is in a degraded state. To determine the degradation level, non-destructive and partially destructive tests were carried out: - a geometric survey with careful detection of the crack patterns;- a georadar survey on a flat and inclined surface of the pier; - pacometric tests on the upper concrete beams to determine the position and the actual diameter of the reinforcement bars; - endoscopic tests to examine the morphology, typology, and state of conservation of the materials of the piers; - mechanical characterization of masonry constituting the piers through extraction of long core specimens to be tested for compression, chemical and mechanical characterization of the mortar; -microhardness tests for estimating the mechanical tensile strength of the steel constituting the bridge deck. The results obtained were utilized to characterize the strength of the constituent materials for static verification of the steel bridge under permanent and accidental loads, according to the Italian Building Code. The results obtained showed that for this bridge there are no risks of failure, but it was not checked against the Eurocodes, and a retrofitting design is still required.

Derivation of the characteristic water pressure resistance of combined steel pile walls

AbstractWorld trade is steadily increasing, leading to a high demand for economic solutions for quay walls. The combined steel pile wall is the most common steel construction solution. The primary elements are king piles, while intermediate piles function as secondary elements. The design of these secondary elements is governed by section 5.5.2 of EN 1993‐5 [9]. The test‐based method described in section 5.5.2(5) and (6) is used to generate the characteristic water pressure resistance values of the different combinations of I‐shaped king and Z‐shaped intermediate piles, each in different steel grades, which are given in the product catalogue of ArcelorMittal [1]. The test series executed and the subsequent setting‐up and validation of a numerical model are presented in detail in this paper. A numerical model was used for a parametric study. The different failure modes observed in this parametric study are presented. A statistical evaluation according to Annex D of EN 1990 [6] and Annex C of EN 1993‐1‐5 [8] leads to characteristic resistance values.

Effect of Intermediate Sheet Piles in Non-Homogenous Soil on Seepage Properties Under Hydraulic Structure Using SEEP/W Program

The seepage through a permeable soil under hydraulic structure exerts uplift pressure and may carry soil particles there by leads to piping. This paper concerns to study the effect of using intermediate sheet pile under the apron of hydraulic structure besides the upstream and downstream piles rest on non-homogeneous soil layer. This configuration aim to show how it affect the uplift pressure, exit gradient and seepage discharge at toe of hydraulic structure by using computer program SEEP/W Package.From the software test carried out two cases, first case using two sheet pile one at the upstream and the other at the downstream, then compare its results with the second case when the sheet pile at upstream, downstream and intermediate pile introduced Also for each run the quantity of uplift pressure, exit gradient and discharge at toe of hydraulic structure were determined to develop an empirical equations. Also, the results have been verify with artificial neural network (ANN), this verification shown good agreement between them.

Effect of aggregate storage piles configuration on dust emissions

Fugitive dust emissions from stockpiles in the open storage yards of industrial sites and the subsequent atmospheric dust dispersion have brought about many ecological and economical problems. This paper introduces a new approach to estimate emission rates using data from Computational Fluid Dynamics simulations. Flow around stockpiles of varying configurations was studied using a previously validated numerical model. Different pile height scenarios, corresponding to a constant material volume and a fixed angle of repose, were exposed to various wind speeds. Flow analysis over the piles showed the importance of using 3D simulations to fully understand the close linkage between flow processes and particles uptake. Data obtained were then integrated in order to evaluate dust emission rates. Results provide evidence to suggest that changing pile configuration can reduce dust emissions. It was found that, for the range of wind conditions and pile dimensions tested, the intermediate pile height configurations lead to a better overall protecting effect from wind and thus were found to produce lower dust emissions.

Puente sobre el río Ferreira (España)

The purpose of this bridge is to improve the intersection of the CN.540 road, from Lugo to Orense, with the 547 road. The chosen structural type meets the conditions of quick construction and cheapness that were paramount in this case. The superstructure of the bridge consists of six intermediate piles, and two abutments, which support seven straight spans with metallic longerons and reinforced concrete deck. The span over the river is 21 m long, and de others, all equal, are 15 m long.The total deck width is 9 m, of which 7 m are for road pavement, and 1 m on each side is reserved for pedestrians sidewalks. The reinforced concrete piles form portal frames, and have circular supports and rectangular dintels. The foundations consist of reinforced concrete blocks, and rest on layers of metamorphic slate into which the foundations penetrate sufficiently deeply to reach sound rock. The project is completed with approach roads to the bridge and the intersections of the roads that converge on the bridge.

Puente sobre el río Enns, Austria

A road bridge has been recently opened over the Enns river at Steyr (Austria). The purpose is to improve traffic and avoid the bottlenecks that often took place. The bridge is supplemented by three other works of lesser importance, namely two bridges and a tunnel for pedestrians. The bridge structure supporting the decks is cellular, box type. It has three compartments, and four vertical partitions, whose thickness varies from 6 m over the intermediate piles to 2.30 m at the crown. There are three spans, of 47, 101 and 70 m length. The bridge intrados forms a smooth curve. Two overhangs extend from the central structure, and provide sidewalks for pedestrians: the deck itself having a width of 17 m. The structure was made in successive overhangs, in 3.50 m sections. Longitudinal prestressing, by means of PZ-A-100 type cables, was done by applying an initial loading of 120 t. The cables run in tubes. After the concrete had reached a suitable strength, the cables were stretched. The tubes were then filled with cement mortar, and in this operation air suction equipment was utilised to make sure that no air cavities were left.

A Scale for Measuring Attitude Toward the Movies

The purpose of this paper is to present a scale for measuring attitude toward the and to describe the method of its construction. This study was undertaken as one of the projects of the Payne Fund of New York. The research program is directed by Professor W. W. Charters of Ohio State University. The original collection of opinions about the movies consisted of two hundred and fifty-eight statements. These opinions, each of which reflects an attitude toward the movies, vary from statements decidedly in favor of the movies through neutral statements to those very much opposed to the movies. They were obtained from literature on the sub ject, from conversation, and from direct questioning of subjects whose education and experience varied from that of seventh grade children to that of graduate students in the University. Each statement was then typewritten on a separate card. As a preliminary method of eliminating the most unsatisfactory and retain ing the best statements, as well as to get an approximate idea of the scale values of the statements, the method of equal-appearing intervals1 was used with a small group of sorters. Twenty-five people, who had some understanding of the method being used and who were carefully chosen to make sure that the directions would be thoroughly under stood and complied with, sorted the cards into eleven piles according to the following instructions: These cards contain statements about the value of the movies. Please arrange these cards in eleven piles so that those expressing atti tudes most strongly in favor of the movies are in pile one, those which are neutral are in pile six, and those which are most strongly against th? movies are in the eleventh pile. The intermediate piles should rep resent equal steps in appreciation or depreciation of the movies. ' ' Do not try to get the same number of cards in each pile. They are not evenly distributed.