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Journal articles on the topic 'Straight piles'

Author: Grafiati

Published: 4 June 2021

Last updated: 9 February 2022

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1

Khan, M. Kamran, M. Hesham El Naggar, and Mohamed Elkasabgy. "Compression testing and analysis of drilled concrete tapered piles in cohesive-frictional soil." Canadian Geotechnical Journal 45, no. 3 (March 2008): 377–92. http://dx.doi.org/10.1139/t07-107.

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When pile driving is difficult and (or) economically not viable, cast-in-place piles are indispensable. Tapered piles, which have top cross-sections larger than the bottom cross-sections, have the potential for substantial advantages over conventional straight-sided piles. This paper investigates the construction and performance of innovative drilled concrete tapered piles. A full-scale pile load-testing program was conducted to evaluate the axial compressive capacity of drilled concrete tapered piles in frictional soil. One straight and three tapered augers were designed and manufactured to produce six piles. The piles that were constructed and tested included four tapered and two straight piles. The testing results showed that tapered piles with a taper angle varying between 0.95° and 1.91° had a load carrying capacity up to 50% higher than the straight-sided piles with equal volume. It should be noted, however, that the experimental results are site specific. Moreover, an analytical expression was developed to evaluate the pile taper effect on its shaft capacity in terms of a taper coefficient, Kt. The value of Kt evaluated from the analytical expression compared well with experimentally measured values. Finally, a two dimensional nonlinear finite element analysis was conducted to simulate the load test conditions, and it proved to be successful.

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2

El Naggar, M. Hesham, and Jin Qi Wei. "Uplift behaviour of tapered piles established from model tests." Canadian Geotechnical Journal 37, no. 1 (February 1, 2000): 56–74. http://dx.doi.org/10.1139/t99-090.

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Tapered piles have a substantial advantage with regard to their load-carrying capacity in the downward frictional mode. The uplift performance of tapered piles, however, has not been fully understood. This paper describes the results of an experimental investigation into the characteristics of the uplift performance of tapered piles. Three instrumented steel piles with different degrees of taper were installed in cohesionless soil and subjected to compressive and tensile load tests. The soil was contained in a steel soil chamber and pressurized using an air bladder to facilitate modelling the confining pressures pertinent to larger embedment depths. The results of this study indicated that the pile axial uplift capacity increased with an increase in the confining pressure for all piles examined in this study. The ratios of uplift to compressive load for tapered piles were less than those for straight piles of the same length and average embedded diameter. The uplift capacity of tapered piles was found to be comparable to that of straight-sided wall piles at higher confining pressure values, suggesting that the performance of actual tapered piles (with greater length) would be comparable to that of straight-sided wall piles. Also, the results indicated that residual stresses developed during the compressive loading phase and their effect were more significant on the initial uplift capacity of piles, and this effect was more pronounced for tapered piles in medium-dense sand.Key words: tapered piles, uplift, axial response, load transfer, experimental modelling.

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3

Kong, Desen, Meixu Deng, and Yazhou Li. "Experimental Study on Mechanical Deformation Characteristics of Inclined and Straight Alternating Pile Groups." Advances in Civil Engineering 2020 (March 23, 2020): 1–11. http://dx.doi.org/10.1155/2020/8394182.

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In order to investigate the bearing characteristics of inclined straight alternating pile groups under vertical and horizontal loads, the indoor model test of 2 × 2 inclined straight alternating pile groups with two layers of soil on low pile caps was carried out, the manufacturing method of inclined straight alternating pile groups was studied, and the test scheme was reasonably designed. In the test, the fast maintenance load method was used to simulate vertical loads, and the horizontal force loading frame was designed to simulate horizontal loads. The experimental data were obtained by pasting strain gauges on the pile body, and the computer was used to process the data according to the mechanical formula. The distribution of axial force, lateral friction resistance, and end resistance of each characteristic pile of the pile group foundation was obtained, and the settlement law of the pile group was analyzed. At the same time, combined with the test data and the existing theories, the interaction mechanism between pile caps, piles, and soil of inclined and straight alternating pile groups is discussed. The load sharing characteristics between piles and pile caps are analyzed, and the horizontal load is in the proportion between straight piles and inclined piles. The stress characteristics of straight piles and pile groups in the pile group system are compared and analyzed, and some valuable conclusions are obtained.

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4

Manandhar, Suman, Noriyuki Yasufuku, Kiyoshi Omine, and Taizo Kobayashi. "Response of tapered piles in cohesionless soil based on model tests." Journal of Nepal Geological Society 40 (December 1, 2010): 85–92. http://dx.doi.org/10.3126/jngs.v40i0.23613.

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This paper describes model tests of different types of tapered piles in cohesionless soils. Chromium plated three steel piles, one straight and two taper-shaped piles of same length and pile tip diameters have been executed for pile loading test in a downward frictional mode. Two different types of model grounds have been prepared for the test. Relative densities of 80 % and 60 % have been modeled to penetrate piles in two different types of sands to observe the effectiveness of skin frictions of different types of piles. The response of tapered piles has shown that the skin friction has increased with increasing the tapering angle at normalized settlement ratio of 0.4. High density ground yields higher skin friction when the maximum tapered pile was penetrated. Slightly increased tapering angle of the pile affects remarkably on the skin friction with compared to conventional straight cylindrical pile even at small 0.1 settlement ratios.

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5

El Naggar, M. Hesham, and Jin Qi Wei. "Axial capacity of tapered piles established from model tests." Canadian Geotechnical Journal 36, no. 6 (December 1, 1999): 1185–94. http://dx.doi.org/10.1139/t99-076.

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Tapered piles represent a more efficient distribution of pile material than uniform cross section piles in several respects. An extensive experimental research program was conducted to study the efficiency of tapered piles compared with piles of uniform cross section with the same material input. Three instrumented model steel piles with different degrees of taper were used in this program. The piles were tested in a large-scale laboratory setup under compressive and tensile loads. The pile head load and displacement and the strain along the piles were measured simultaneously. The objectives of the present paper were twofold: to examine the validity of the experimental results, and to use the unit load transfer curves established from the experimental results to predict the bearing capacity of prototype tapered piles. The shaft resistance for straight-sided wall piles established from the experimental results compared well with the theoretical predictions using the standard design procedure. The beneficial effect of pile taper was significant up to a depth of 20 pile diameters. The negative effect of the pile taper on the uplift capacity diminished quickly with depth and hence the performance of actual tapered piles (with greater length) would be comparable to that of straight-sided wall piles.

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6

Song, Bo, Hai Long Wang, and Shi Jing Liu. "Comparative Study on Seismic Design Method of High-Piled Wharf of Different Depth in China and Japan." Advanced Materials Research 919-921 (April 2014): 1043–46. http://dx.doi.org/10.4028/www.scientific.net/amr.919-921.1043.

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As many high-piled wharves are in an earthquake zone in home and abroad, so it is vitally important to conduct seismic design to ensure them with a certain seismic capacity. Studies showed that the wharves with straight piles have better seismic performance than wharves with oblique pile. According to the standards in China and Japan, this paper will compare the indicators of seismic performance, including the calculation length of piles, seismic inertial force, bearing capacity etc. The difference between Chinese code and Japanese code will be confirmed through comparison. The comparative results show that the differences mainly in the embedded solid position and the horizontal force etc. Additionally, according to the comparison of different depth of high-piled wharf, there is an increasing trend of the indicators with increasing depth of water.

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7

El Naggar, M. Hesham, and Jin Qi Wei. "Response of tapered piles subjected to lateral loading." Canadian Geotechnical Journal 36, no. 1 (August 8, 1999): 52–71. http://dx.doi.org/10.1139/t98-094.

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Eighteen lateral loading tests were conducted on large-scale steel piles to establish the lateral behaviour of tapered piles in cohesionless soil. Three piles 1.52 m in length with different taper angles but the same average embedded diameter of 168 mm were installed in sand enclosed in a steel chamber 1.5 m in diameter and 1.445 m in depth. The soil chamber was lined with an air bladder so that sand inside the chamber could be pressurized to vary the confining pressure. The piles were instrumented with electrical resistance strain gauges and the horizontal pile movements at grade and the loading point were measured with displacement transducers. The bending-moment functions along the pile were calculated from the strain measurements by curve fitting the measured strain data. The soil resistance (p) and pile displacement (y) relationships were developed in the form of p-y curves by differentiating and integrating these bending-moment functions. It was found that tapered piles carried up to 77% more lateral loads than straight-sided-wall piles with the same average diameter. The maximum bending moment occurred in all piles at almost the same depth of one third of the embedded length of the pile. Hence, the cross section of tapered piles at the location of maximum bending moment was larger than that of straight-sided-wall piles, resulting in lower stresses in the pile. It was concluded that the tapered piles represent a more efficient distribution of the pile material and display better performance under lateral loading conditions.Key words: tapered piles, lateral response, p-y curves, modulus of subgrade reaction.

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8

Hou, Yan Jun, and Lin Feng Wu. "Orientation Schemes Choice for Aquatic Inserting Piles Based on Gray Relation Analysis." Advanced Materials Research 503-504 (April 2012): 909–12. http://dx.doi.org/10.4028/www.scientific.net/amr.503-504.909.

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In the process of rapid orientation device design for aquatic inserting piles, piles were fixed position using straight and steady function of the edge piles ahead. Piles were inserted to riverbed inside steel casing without horizontal current velocity. Three kinds of orientation schemes were put forward. To scientifically and accurately choose the best scheme, the evaluation index system was established in the way of expert's mark. The gray relation analysis method was adopted to analyze each scheme, synthesize each factor, and finally educe the optimal scheme.

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9

Nursita, Ersalia Dewi. "Penentuan Jarak Antar Tiang Penerangan Jalan Umum Untuk Jalan Lurus Dan Jalan Melengkung Pada Jalan Tol Ruas Lingkar Luar Jakarta W2 Utara Seksi I." Energi & Kelistrikan 12, no. 2 (December 22, 2020): 121–30. http://dx.doi.org/10.33322/energi.v12i2.1063.

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The Jakarta Outer Ring Road North W2 Section I has a different road width and also an interchange that is curved like a circle. On this toll road the distance between the piles used in both type of road is the same, that is equal to 30 m. Determination of the distance between the poles of the street lighting for straight roads and curved paths in this thesis using the phytagoras method. Where the distance between the lampposts for a straight road with the width of the road ranges from 4.5 m to 14.5 m from the calculation results require the distance between piles of 21.09 to 29.85 (<30 m) this results in less lighting standard. And for the width of the road ranging from 15.5 m to 30.5 m from the calculation results require the distance between the piles of 31.01 m to 50.82 m (> 30 m) which results in waste in the installation of the number of poles. Whereas for curved roads with a road width of 7.5 m for the placement of light poles in the arches of the road requires a smaller distance between piles of 20.96 m (<30 m).

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10

Dickin, E. A., and C. F. Leung. "Performance of piles with enlarged bases subject to uplift forces." Canadian Geotechnical Journal 27, no. 5 (October 1, 1990): 546–56. http://dx.doi.org/10.1139/t90-070.

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The influence of embedment, base diameter, and backfill density on the uplift behaviour of piles with enlarged bases embedded in sand was investigated in a centrifuge. Comparitive tests on straight-shafted piles are also reported. For piles in dense sand, sensible agreement was found with earlier research on anchor plates and published field data. However, uplift capacities in loose sand were considerably lower than previously observed for anchor plates. A number of theories for anchors considerably overpredict the observed capacity for belled piers in both dense and loose sand, although in the case of dense sand, reasonable values are obtained using an empirical equation derived from centrifuge tests on anchor plates and a finite element based design approach. The normally conservative vertical slip-surface model is alone in providing reasonable agreement with the surprisingly low observations for piles in loose sand. Key words: piles, uplift capacity, centrifuge tests, sand.

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11

Tang, Song Tao, and Li Hong Chen. "Field Test of DX Pile Group." Advanced Materials Research 243-249 (May 2011): 2451–55. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.2451.

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DX pile is a newly developed variable cross-section pile. Compared to conventional straight pile, it has distinct advantages on bearing capacity and settlement control. However, the bearing mechanism and characteristics of settlement, especially on group DX piles, are not clear. This paper illustrated and analyzed the bearing capacity and settlement characteristics of single DX pile and group DX piles according to the test results of in-situ model test. Special attention was paid on single and group DX pile comparison under same circumstances, at the mean while, compared the single DX pile and conventional pile with the same pile length and diameter, and with the same bearing capacity. The conclusions from the test results provided theoretical references for the design of the DX piles in engineering practices.

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12

Zhou, Junpeng, Jun Yuan, Xuefeng Huang, and Xueming Wang. "Numerical Simulation Study on the Influence of Different Factors on the Uplift Bearing Capacity of Root Piles, Straight-Shaft Piles, and Pedestal Piles." Advances in Civil Engineering 2020 (November 16, 2020): 1–15. http://dx.doi.org/10.1155/2020/8853131.

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Root pile (hereafter called RP), which is a promising new type of noncircular cross-section-shaped pile and meets the requirements of the development of the uplift pile, was introduced for promotion. On the basis of validation of experimental and numerical results, finite element models were established to study the influence of the arrangement of roots and dimension parameters on the uplift bearing capacity and the economy of RP compared with that of the straight-shaft pile and pedestal pile (hereafter called SP and PP, respectively). The results show that the uplift bearing capacity of RP is higher than that of SP and PP, and the longer the pile length is, the more the bearing capacity of RP would increase compared with that of SP and PP. In order to further improve the bearing capacity of RP, the bearing mechanism of the root was analysed, and the suggested values of root size and spacing of layers are given. In addition, the most economical way to increase pile bearing capacity is to increase pile length rather than increasing pile diameter.

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13

Manandhar, Suman, and Noriyuki Yasufuku. "Analytical Model for the End-Bearing Capacity of Tapered Piles Using Cavity Expansion Theory." Advances in Civil Engineering 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/749540.

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On the basis of evidence from model tests on increasing the end-bearing behavior of tapered piles at the load-settlement curve, this paper proposes an analytical spherical cavity expansion theory to evaluate the end-bearing capacity. The angle of tapering is inserted in the proposed model to evaluate the end-bearing capacity. The test results of the proposed model in different types of sands and different relative densities show good effects compared to conventional straight piles. The end-bearing capacity increases with increases in the tapering angle. The paper then propounds a model for prototypes and real-type pile tests which predicts and validates to evaluate the end-bearing capacity.

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14

Qian, Yongmei, Tingting Zhou, and Wei Tian. "Anti-Overturning Bearing Capacity of Rigid and Flexible Concrete Expanded Piles Subjected to Horizontal Load." Advances in Civil Engineering 2020 (July 8, 2020): 1–14. http://dx.doi.org/10.1155/2020/4901069.

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The concrete expanded pile is a new type of pile in the field of foundation engineering, which exhibits improved performance compared to the ordinary straight-hole pile. The expanded technique increases the bearing capacity of the pile, changes the overall load-bearing function of the pile body, and offers great development prospects. While the performance of the expanded pile has been studied for vertical loading, the performance of expanded pile when subjected to horizontal loading is not adequately understood. In order to investigate the performance of concrete expanded pile in resisting horizontal loads, particularly the anti-overturning capacity of rigid and flexible piles, this paper conducts an experimental model test and performs a numerical simulation. In the experiment, an innovative model test method is used for testing small-scale half-face pile with undisturbed soil. A custom-made soil extractor and a loading device are used to observe various stages of pile-soil interaction in real-time during the whole process of loading. Meanwhile, finite element simulation analysis is conducted on a pile model and the corresponding data on displacement, load, stress, and strain are collected to verify the experimental results. Based on the horizontal bearing capacity of rigid and flexible piles and the failure states of soil mass around the piles, two calculation models are proposed for the horizontal bearing capacity of rigid and flexible concrete expanded piles. The models will provide reliable theoretical guidance for the application of concrete expanded pile in engineering applications and for the research and development of pile foundation.

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15

Ziyara, H. M., and B. S. Albusoda. "An experimental study of the load carrying capacity of straight shaft and underreamed piles in expansive soil." IOP Conference Series: Materials Science and Engineering 1067, no. 1 (February 1, 2021): 012050. http://dx.doi.org/10.1088/1757-899x/1067/1/012050.

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16

Маций, Сергей, Sergey Maciy, and Дарья Лейер. "Research of Interaction of Landslide Soil with Protective Constructions of Support of Platforms." Construction and Architecture 1, no. 1 (May 1, 2013): 49–53. http://dx.doi.org/10.12737/341.

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Designing protective structures for trestle bents from deformations caused by landslides faces the problem of proper place- ment of pile elements. For developing effective landslide barriers for every single trestle bent, the calculation scheme is being proposed. It simulates interaction between landslide soil and the piles of straight line protective structure. Calculation scheme carried out using finite-elements method with geotechnical software Plaxis. In the process of analyzing the interaction between landslide’s loamy soil (with low strength characteristics) and single protective structure some of the most distinctive relationships were estimated: graphical characteristics of soil deformation in dependence from pile space and loaded force and also relationships between limited soil displacement as well as landslide pressure and structure’s configuration. The achieved results were compared with the ones from laboratory testing. Effective placement of pile elements in single protective structures was estimated on the basis of complex analyzing.

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17

McArthur, Tom. "A transcontinental distribution." English Today 22, no. 1 (January 2006): 2. http://dx.doi.org/10.1017/s0266078406001015.

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The difference over twenty years, in the making of ET since 1985, includes the vanishing away of paper files. In a cabinet beside my desk I have A–Z files for the many people who literally ‘wrote’ – that is, typed – to me on paper. I almost never consult any of those files now, and don’t remember when I last added a sheet to them. Instead, of course, I check my email, which piles up electronically in non-real space somewhere inside this machine in front of me. And, though I strive to keep my records straight, I seldom check back very far or go into e-files of old e-mails. And, most days, whether in Cambridge or in Hong Kong, I read daily e-abstracts from my much-prized Edinburgh newspaper, The Scotsman, and don't recall when I last saw, leave alone bought and read, a conventional paper edition of it.

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18

Pauli, Nathan Stephen, and Gustavo Gioia. "The topography of steady sandpiles on arbitrary domains." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 463, no. 2081 (February 13, 2007): 1247–58. http://dx.doi.org/10.1098/rspa.2007.1812.

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If sand is continually and slowly added onto a table, a pile will grow and reach some steady state, whereupon any further sand added to the pile will fall off the table, leaving the surface of the pile unchanged. A construction that gives the surface of a unique steady pile for a table of any given shape was proposed by Arpad L. Nadai. Here, we show that Nadai's construction can be justified mathematically on the basis of a few plausible assumptions on the mechanical behaviour of sand. We also show that the surface of the steady pile given by the construction is the maximal topography supported on the domain of the table; that the surface may contain smooth patches, valleys, peaks and ridges; that any smooth patch is developable; that any valley is smooth, straight and without tributaries, and has a slope equal to the angle of repose of the sand; that any peak is sharp; and that any ridge is sharp and has a slope less than the angle of repose of the sand. Lastly, we perform simple experiments and verify that actual steady piles look similar to those given by the construction, with a precision that depends on the type of sand and how carefully the sand is poured to form a pile.

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19

Adeel Tariq, Khawaja, Muhammad Moeen Soharwardy, and Nadeem Ahmed Tabessum. "Evaluation of Soil Engineering Characteristics in Jalalpur Region, Pakistan." July 2019 38, no. 3 (July 1, 2019): 745–54. http://dx.doi.org/10.22581/muet1982.1903.17.

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This study deals with the evaluation of soil engineering characteristic along the proposed route of Jalalpur irrigation project. The proposed JIP (Jalalpur Irrigation Project) is located along the right bank of Jhelum River in Tehsil PDK (Pind Dadan Khan) and Tehsil Khushab of District Khushab. JIP is funded by ADB (Asian Development Bank). The JIP will enhance crop production in Tehsil PDKand Khushab. Farmers will be benefited through JIP as they will get regular supply of water through canal. It will also create job opportunities for local people and will lead to the prosperity of the Project area. Detailed soil investigation along proposed route was carried out by M/S GEO BAND. Straight rotary method of drilling was used. The recovered soil samples and water samples were tested in laboratories. The detailed engineering analysis was performed and soil parameters along with bearing capacities are suggested. Results have indicated variations in SPT values along the proposed route. The top layer of soil along proposed route is mostly Silty Clay with variation along the depth. The proposed bearing capacity for shallow foundation is 1.25 ton/ft2 (120 kN/m2) at depth of 5ft (1.5 m) beneath footing, and for bored piles having diameter of 2.5 ft (0.76 m) at a depth of 50 ft (15 m) is recommended as 70 ton (685 kN). The results presented in this study will be helpful in deciding the detailed foundation design of the engineering structures along the proposed route of JIP.

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20

Meijer, Gerrit J., David Muir Wood, Jonathan A. Knappett, A. Glyn Bengough, and Teng Liang. "Root branching affects the mobilisation of root-reinforcement in direct shear." E3S Web of Conferences 92 (2019): 12010. http://dx.doi.org/10.1051/e3sconf/20199212010.

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The contribution of roots to the mechanical behaviour of soil has typically only been studied for the ultimate limit state. In these approaches, roots are typically modelled as straight and unbranched structures. This approach overlooks the fact that roots may have to deform significantly to mobilise their strength, a process that will be influenced by root architecture effects such as branching, amongst others. Sequential mobilisation of roots affects the peak root-reinforcement, thus differences in mobilisation are important to consider when quantifying root-reinforcement. In this paper, the effect of root branching was modelled using a large-deformation Euler-Bernoulli beam-spring model. The effect of soil was incorporated using non-linear springs, similar to p-y and t-z theory used for foundation piles. By connecting multiple beams together (i.e. applying appropriate linked boundary conditions at root connection points) the effect of branching could be analysed. A soil displacement profile corresponding with direct shear loading was then imposed and the response of the root analysed. It was shown that adding branches led to a quicker mobilisation of root-reinforcement. Branches increased the axial resistance to root displacement and changed the shape of the deformed roots. The presence of branching counteracted root slippage, and thus increased reinforcement. Larger branching densities increased this effect. This analysis demonstrated that the architecture of the root system has a strong effect on the mobilisation of root strength, which directly affects the maximum amount of reinforcement the roots will provide. Future modelling of root-reinforcement, both at the ultimate and serviceable limit state, should account for this effect.

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21

CAZZANI, ANTONIO. "ON THE DYNAMICS OF A BEAM PARTIALLY SUPPORTED BY AN ELASTIC FOUNDATION: AN EXACT SOLUTION-SET." International Journal of Structural Stability and Dynamics 13, no. 08 (October 21, 2013): 1350045. http://dx.doi.org/10.1142/s0219455413500454.

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Free vibrations of straight beams which are partially supported by an elastic foundation are analyzed. For the sake of simplicity, only the Euler–Bernoulli beam model coupled with a Winkler-type elastic foundation is considered. This structural system can be used to study, in a rather accurate way, the dynamic response of partially embedded piles (like those used for telecommunications) when dealing with the problem of identifying their mechanical properties during operative conditions. The study makes clear that different kinds of vibration modes may occur in the part of the beam which is supported by the continuous elastic foundation: indeed apart from the classical modes, corresponding to the dynamics of a free beam, it is possible to have vibration modes which are similar to the static deflection of a beam on an elastic support or even corresponding to rigid-body modes. For the same beam it is shown that transition between these vibration modes can appear when switching from the fundamental natural frequency to subsequent ones. This effect is the focus of the presented numerical examples. In particular, the analytic expression of the transcendental functions governing the vibration modes, and of the coefficients of the eigenfunctions for all occurring cases, are given here — to the best of the author's knowledge — for the first time. From the practical point of view, the reported results allow to define a suitable range of the elastic stiffness parameter such that the behavior of a partially supported beam can be conveniently approximated with that of a single-span beam, having one built-in end and the other free.

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22

Uehara, Akira, Wataru Inaba, Jyun-ichi Eino, and Takumi Hashizume. "C203 DIAGNOSIS OF THICKNESS IN PIPES AND HEAT EXCHANGER TUBES : A CASE OF STRAIGHT PIPES IN WATER LINE(Erosion)." Proceedings of the International Conference on Power Engineering (ICOPE) 2009.2 (2009): _2–191_—_2–196_. http://dx.doi.org/10.1299/jsmeicope.2009.2._2-191_.

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23

Boonyarak, Thayanan, Kullapat Phisitkul, Charles W. W. Ng, Wanchai Teparaksa, and Zaw Zaw Aye. "Observed ground and pile group responses due to tunneling in Bangkok stiff clay." Canadian Geotechnical Journal 51, no. 5 (May 2014): 479–95. http://dx.doi.org/10.1139/cgj-2013-0082.

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A 5.15 m diameter water diversion tunnel was driven into Bangkok stiff clay using an earth pressure balance shield. The tunnel was driven within a clear distance of 2 m from the closest pile of a 3 × 4 pile group supporting an expressway. During construction, tunnel driving parameters as well as induced ground and pile group responses were recorded. To avoid cutting the piles supporting the expressway, the alignment of the tunnel was adjusted and curved. As a result of this change in tunnel alignment, the tunnel advancing rate was reduced from an average 17 m/day for a straight drive to an average of only 6 m/day for the curved alignment, and the ratio between the tunnel face pressure and overburden pressure was changed from 0.5 to 0.4, accordingly. Due to the reduction of the tunnel face pressure, up to a 280% larger inward ground movement towards the tunnel was observed. As the shield penetration rate decreased, the torque required for tunnel driving was reduced by 33%, while the ratio between shield penetration rate and soil extraction was almost constant throughout the tunnel route. A transverse influence zone due to tunnel driving was identified to extend up to a distance that was twice the tunnel diameter radially from the longitudinal tunnel axis. The maximum tilting of the expressway pier and deduced differential settlement of the pile located within the influence zone were up to 1:2600 and 2.0 mm, respectively. Tilting of all the piers was mainly caused by long-term subsurface settlement having the tilting direction towards the tunnel. This long-term subsurface settlement was up to about 80% of the total.

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24

Lei, U., and C. H. Hsu. "Flow through rotating straight pipes." Physics of Fluids A: Fluid Dynamics 2, no. 1 (January 1990): 63–75. http://dx.doi.org/10.1063/1.857693.

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25

TAKAMI, Toshihiro. "Turbulent Flows in Straight Rough Pipes." Transactions of the Japan Society of Mechanical Engineers Series B 63, no. 606 (1997): 537–43. http://dx.doi.org/10.1299/kikaib.63.537.

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26

Pavić, G. "Vibroacoustical energy flow through straight pipes." Journal of Sound and Vibration 154, no. 3 (May 1992): 411–29. http://dx.doi.org/10.1016/0022-460x(92)90776-t.

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27

Ho, A. S., T. A. Mietzner, A. J. Smith, and G. K. Schoolnik. "The pili of Aeromonas hydrophila: identification of an environmentally regulated "mini pilin"." Journal of Experimental Medicine 172, no. 3 (September 1, 1990): 795–806. http://dx.doi.org/10.1084/jem.172.3.795.

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Ultrastructural studies of Aeromonas hydrophila strain AH26 revealed two distinctive pilus types: "straight" pili appear as brittle, rod-like filaments, whereas "flexible" pili are supple and curvilinear. Straight pili are produced constitutively under all tested conditions of growth. In contrast, the expression of flexible pili is regulated by physical and chemical variables, being produced at 22 vs. 37 degrees C, in a liquid vs. a solid medium, and when the availability of free-iron is reduced by the presence of deferoxamine mesylate. Both pilus proteins were purified and biochemically and functionally characterized. The major repeating subunit of the straight pilus is a 17,000-mol wt polypeptide with amino acid sequence homology with Escherichia coli type 1 and Pap pili. The flexible pilus filament is a homopolymer composed of a novel 46 amino acid polypeptide. Resistance of the flexible pilus filament to disaggregation using various chemical treatments was demonstrated; its stability as a polymer and its apparent mechanical strength seem to be conferred by a 20 amino acid hydrophobic, COOH-terminal domain. Purified straight pili lack hemagglutinating function. In contrast, purified flexible pili cause the agglutinin of human, guinea pig, ovine, bovine, and avian erythrocytes, although this property could only be demonstrated in the presence of divalent cations and was most evident at 4 vs. 22 degrees C. Taken together, these results suggest that the pathogenic and ecological roles of the flexible pilus are related to this species' existence as a free-living organism in aquatic environments and its ability to cause infections, both in cold-blooded vertebrates and the human intestine.

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Cheng, K. C., and Liqiu Wang. "Secondary Flow Phenomena in Rotating Radial Straight Pipes." International Journal of Rotating Machinery 2, no. 2 (1995): 103–11. http://dx.doi.org/10.1155/s1023621x9500025x.

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Flow visualization results for secondary flow phenomena near the exit of a rotating radial-axis straight pipe (length ࡁ = 82 cm, inside diameter d = 3.81 cm, ࡁ/d 21.52) are presented to study the stabilizing (relaminarization) and destabilizing (early transition from laminar to turbulent flow) effects of Coriolis forces for Reynolds numbers Re = 500 ∼ 4,500 and rotating speeds n = 0 ∼ 200 rpm. The flow visualization was realised by smoke injection method. The main features of the transition phenomena are disclosed for Re = 1,500 and 4,500. The observed secondary flow patterns are found to be quite different from those obtained by theoretical or numerical analysis with one pair of symmetric and steady counter-rotating vortices. The practical implications of the visualization study are pointed out.

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29

Dosunmu, Idowu T., and Subhash N. Shah. "Turbulent flow behavior of surfactant solutions in straight pipes." Journal of Petroleum Science and Engineering 124 (December 2014): 323–30. http://dx.doi.org/10.1016/j.petrol.2014.09.025.

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30

Noorani, A., G. K. El Khoury, and P. Schlatter. "Evolution of turbulence characteristics from straight to curved pipes." International Journal of Heat and Fluid Flow 41 (June 2013): 16–26. http://dx.doi.org/10.1016/j.ijheatfluidflow.2013.03.005.

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31

Saxena, Sanjeev, N. Ramakrishnan, and J. S. Chouhan. "Fatigue life prediction analysis of surface cracked straight pipes." Transactions of the Indian Institute of Metals 62, no. 3 (June 2009): 191–95. http://dx.doi.org/10.1007/s12666-009-0031-z.

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32

IWASAKI, Takeshi, and Jun OJIMA. "Friction Loss in Straight Pipes of Unplasticized Polyvinyl Chloride." INDUSTRIAL HEALTH 34, no. 3 (1996): 245–56. http://dx.doi.org/10.2486/indhealth.34.245.

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33

Barkley, D. "Taming turbulent fronts by bending pipes." Journal of Fluid Mechanics 872 (June 4, 2019): 1–4. http://dx.doi.org/10.1017/jfm.2019.340.

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The flow of fluid through a pipe has been instrumental in illuminating the subcritical route to turbulence typical of many wall-bounded shear flows. Especially important in this process are the turbulent–laminar fronts that separate the turbulent and laminar flow. Four years ago Michael Graham (Nature, vol. 526, 2015, p. 508) wrote a commentary entitled ‘Turbulence spreads like wildfire’, which is a picturesque but also accurate characterisation of the way turbulence spreads through laminar flow in a straight pipe. In this spirit, the recent article by Rinaldi et al. (J. Fluid Mech., vol. 866, 2019, pp. 487–502) shows that turbulent wildfires are substantially tamed in bent pipes. These authors find that even at modest pipe curvature, the characteristic strong turbulent–laminar fronts of straight pipe flow vanish. As a result, the propagation of turbulent structures is modified and there are hints that the route to turbulence is fundamentally altered.

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34

Vishnuvardhan, S., G. Raghava, P. Gandhi, M. Saravanan, D. M. Pukazhendhi, Sumit Goyal, Punit Arora, and Suneel K. Gupta. "Fatigue ratcheting studies on TP304 LN stainless steel straight pipes." Procedia Engineering 2, no. 1 (April 2010): 2209–18. http://dx.doi.org/10.1016/j.proeng.2010.03.237.

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35

Olson, J. R., and G. W. Swift. "Energy dissipation in oscillating flow through straight and coiled pipes." Journal of the Acoustical Society of America 100, no. 4 (October 1996): 2123–31. http://dx.doi.org/10.1121/1.417922.

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36

Fan, Li-feng, Pei Liang, Ge Wang, Ying Gao, and Benguo Zhang. "Precision Forming Technology for Crimping of Large Straight Welded Pipes." Advances in Materials Science and Engineering 2019 (October 31, 2019): 1–9. http://dx.doi.org/10.1155/2019/1376164.

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Crimping plays a pivotal role in the production of large-diameter submerged-arc welded pipes. In the crimping forming process, predicting the springback while considering the real-time variation of material parameters is a major challenge faced by many researchers, which has a direct impact on the quality of the welded pipe. To address this problem, the precision forming technology of crimping was developed. The engineering theory of plastic bending was used to investigate the crimping forming process. Two methods, namely, the slope reverse method and the optimization method, were adopted to identify the material parameters. The results showed that the inverted material parameters can be evaluated in real time based on the analytical model of crimping. The maximum relative error of the identification value is less than 4%. Therefore, the springback and displacement during crimping can be predicted dynamically to control the crimping forming quality. Thus, this project provides an important opportunity to achieve precise forming through crimping.

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37

KUMAR, D. VENU, D. S. RAMACHANDRA MURTHY, S. SEETHARAMAN, S. K. GUPTA, V. BHASIN, K. K. VAZE, and H. S. KUSHWAHA. "Cyclic tearing and crack growth in circumferentially cracked straight pipes." Fatigue & Fracture of Engineering Materials & Structures 27, no. 11 (September 9, 2004): 1061–72. http://dx.doi.org/10.1111/j.1460-2695.2004.00822.x.

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38

Demma, A., P. Cawley, M. Lowe, and B. Pavlakovic. "The Effect of Bends on the Propagation of Guided Waves in Pipes." Journal of Pressure Vessel Technology 127, no. 3 (February 3, 2005): 328–35. http://dx.doi.org/10.1115/1.1990211.

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The practical testing of pipes in a pipe network has shown that there are issues concerning the propagation of ultrasonic guided waves through bends. It is therefore desirable to improve the understanding of the reflection and transmission characteristics of the bend. First, the dispersion curves for toroidal structures have been calculated using a finite element method, as there is no available analytical solution. Then the factors affecting the transmission and reflection behavior have been identified by studying a straight-curved-straight structure both numerically and experimentally. The frequency dependent transmission behavior obtained is explained in terms of the modes propagating in the straight and curved sections of the pipe.

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39

Zhou, Liu Ru. "A Study on Incremental Forming of Vertical Wall Square Box with Small Radius Corner." Advanced Materials Research 139-141 (October 2010): 1510–13. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.1510.

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According to sine law, a vertical wall square box can’t be formed by NC incremental sheet metal forming process in a single process, rather, it must be formed in multi processes. A vertical wall square box can be considered to consist of corners and straight sides. Straight sides and corners affect each other and the effect is different in various square boxes. The effect depends on the ratio r/B of the corner radius r and straight side width B. The smaller r/B, the larger the effect of straight side on corner is. In this case, the deformation in the straight sides isn’t even, and the metal of the corner is compressed and gradually piled up. With the increase of r/B, the deformation becomes more uniform. The tool path with gradually reduced corner radius is adopted to overcome this question. A vertical wall square box with small corner radius is successfully formed.

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40

Jinxin, Dou, Yang Tongguang, Yu Xiaoguang, Xue Zhengkun, Liu Zhongxin, and Sun Jie. "Model-driven fault diagnosis of slant cracks in aero-hydraulic straight pipes." Advances in Mechanical Engineering 12, no. 9 (September 2020): 168781402095497. http://dx.doi.org/10.1177/1687814020954970.

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A model-driven fault diagnosis method for slant cracks in aero-hydraulic straight pipes is presented in this paper. First, fracture mechanics theory and the principle of strain energy release are used to derive an expression for the local flexibility coefficient of straight pipes with slant cracks. The inverse method of total flexibility is used to calculate the stiffness matrix of straight pipe elements with slant cracks. Second, the Euler-Bernoulli beam model theory is used in conjunction with the finite element method to construct a dynamic model of the cracked pipe. Finally, a contour map method is used to diagnose the slant crack fault and quantitatively determine the crack position and depth. Experimental results show that the proposed method can accurately and effectively identify a slant crack fault in aero-hydraulic pipelines.

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41

Perangin-angin, Siwan E., and Himsar Ambarita. "Comparison of solar water heater performance with u curved pipes and straight pipes design using CFD." IOP Conference Series: Materials Science and Engineering 801 (June 3, 2020): 012056. http://dx.doi.org/10.1088/1757-899x/801/1/012056.

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42

Ishigaki, Hiroshi. "Analogy between laminar flows in curved pipes and orthogonally rotating pipes." Journal of Fluid Mechanics 268 (June 10, 1994): 133–45. http://dx.doi.org/10.1017/s0022112094001291.

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The secondary flow of a viscous fluid, caused by the Coriolis force, through a straight pipe rotating about an axis perpendicular to the pipe axis is analogous to that of a fluid, caused by the centrifugal force, through a stationary curved pipe. The quantitative analogy between these two fully developed laminar flows will be demonstrated through similarity arguments, computational studies and the use of experimental data. Similarity considerations result in two analogous governing parameters for each flow, which include a new one for the rotating flow. When one of these analogous pairs of parameters of the two flows is large, it will be demonstrated that there are strong similarities between the two flows regarding friction factors, heat transfer rates, flow patterns and flow properties for the same values of the other pair of parameters.

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43

Cui, Ai Qiang, Shao Ping Zhou, Wen Chao Lv, and Chang Li Liu. "Simulation Research on Defects Detection in Straight Pipes Using Guided Waves." Applied Mechanics and Materials 226-228 (November 2012): 526–30. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.526.

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Ultrasonic guided wave provides a suitable fast screening technique that enables the localization of the defects and offers a rough estimation of the defect size in pipes. Using the ANSYS, the entity model of a pipe with defects such as cracks and holes was established in this paper. Then the L(0,2) mode guided wave was excited by exerting symmetric displacement loads on an end of the pipe model. By analyzing the incident wave and the reflected wave of defects, the axial location and circumferential location of the defects can be reached. Besides, by fitting the data with some certain formulas, the relationships between reflection coefficient and the defects extent can be acquired. This new technique is of great significance in nondestructive detection.

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44

Tsang, Ernest K. W., Miroslav Kocifaj, Danny H. W. Li, František Kundracik, and Jitka Mohelníková. "Straight light pipes’ daylighting: A case study for different climatic zones." Solar Energy 170 (August 2018): 56–63. http://dx.doi.org/10.1016/j.solener.2018.05.042.

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45

Torres, Germán, and Cristina Turner. "Method of straight lines for a Bingham problem in cylindrical pipes." Applied Numerical Mathematics 47, no. 3-4 (December 2003): 543–58. http://dx.doi.org/10.1016/s0168-9274(03)00088-6.

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46

SAXENA, S. "Assessing the accuracy of fatigue life in surface-cracked straight pipes." Fatigue & Fracture of Engineering Materials & Structures 34, no. 12 (May 30, 2011): 1003–11. http://dx.doi.org/10.1111/j.1460-2695.2011.01589.x.

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47

SHATAT, Mohammed M. E., Shinichiro YANASE, Toshihiro TAKAMI, and Toru HYAKUTAKE. "Drag Reduction Effects of Micro-Bubbles in Straight and Helical Pipes." Journal of Fluid Science and Technology 4, no. 1 (2009): 156–67. http://dx.doi.org/10.1299/jfst.4.156.

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48

Vishnuvardhan, S., G. Raghava, P. Gandhi, M. Saravanan, Sumit Goyal, Punit Arora, Suneel K. Gupta, and Vivek Bhasin. "Ratcheting failure of pressurised straight pipes and elbows under reversed bending." International Journal of Pressure Vessels and Piping 105-106 (May 2013): 79–89. http://dx.doi.org/10.1016/j.ijpvp.2013.03.005.

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49

Song, Tae Kwang, Chang Kyun Oh, Yun Jae Kim, Jong Sung Kim, and Tae Eun Jin. "Approximate J Estimates for Circumferential Cracks in between Elbows and Attached Pipes." Key Engineering Materials 345-346 (August 2007): 521–24. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.521.

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The present work proposes a method for elastic-plastic fracture mechanics analysis of the circumferential through-wall crack in between elbows and attached straight pipes, subject to in-plane bending. Based on small strain finite element limit analyses, closed-form limit load solutions are given first. Then applicability of the reference stress based method to approximately estimate J is proposed. One interesting finding is that a popular approach to assume that the crack locates in the straight pipe could lead to significantly different assessment results.

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50

Sahu, M. K., J. Chattopadhyay, and B. K. Dutta. "Fracture studies of straight pipes subjected to internal pressure and bending moment." International Journal of Pressure Vessels and Piping 134 (October 2015): 56–71. http://dx.doi.org/10.1016/j.ijpvp.2015.08.001.

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