The effects of plugging on pile performance and design

1990 ◽  
Vol 27 (4) ◽  
pp. 429-440 ◽  
Author(s):  
Samuel G. Paikowsky ◽  
Robert V. Whitman
Keyword(s):  
Dynamic Analysis ◽  
Key Words ◽  
Dynamic Behavior ◽  
Time Dependent ◽  
Limited Attention ◽  
Pile Driving ◽  
Pile Capacity ◽  
Static Capacity ◽  
Capacity Gain ◽  
Open Pipe

During installation of open-pipe piles, soil enters the pile until the inner-soil cylinder develops sufficient resistance to prevent further soil intrusion and the pile becomes "plugged." In spite of its frequent occurrence, only limited attention has thus far been given to this phenomenon and its consequences. The effects of plugging on pile performance and design are examined in reference to the following aspects: ultimate static capacity, time-dependent pile capacity, and dynamic behavior. Pile plugging is shown to have the following effects: marked contribution to the capacity of piles driven in sand; delay in capacity gain with time for piles driven in clay; and change in behavior of piles during installation, causing it to differ from that described by the models commonly used to predict and analyze pile driving. Key words: pipe piles, pile plugging, open-ended piles, static capacity, time-dependent capacity, dynamic analysis, pile driving, pile performance.

Change in pile capacity with time: case histories

1986 ◽  
Vol 23 (2) ◽  
pp. 174-180 ◽  
Author(s):  
Laval Samson ◽  
Jean Authier
Keyword(s):  
Dynamic Analysis ◽  
Key Words ◽  
Pore Pressure ◽  
Time Factor ◽  
The Other ◽  
Dynamic Monitoring ◽  
Pile Driving ◽  
Case Histories ◽  
Construction Sites ◽  
Pile Capacity

Four case histories where important changes in pile capacity were observed with time are presented. Two show an increase of pile capacity for shaft bearing piles driven into deep sand deposits. The increase occurred over a period longer than needed for pore pressure dissipation. In one case, increases of 33 and 85% in pile capacity were measured 2 and 51 days, respectively, after pile driving. The other two case histories deal with the decrease of pile capacity of close-toe pipe piles driven to shale bedrock. The decrease, determined using dynamic monitoring during initial driving and at restriking a few days later, ranged from 11 to 25%. It is concluded that restriking should be currently practiced on all construction sites to investigate any change in pile capacity after driving. This procedure is particularly recommended for toe bearing piles on shale bedrock. Key words: pile capacity, shaft bearing piles, toe bearing piles, relaxation, soil setup, pile dynamic analysis, shale, time factor, case histories.

Design and Construction of Three Instrumented Test Piles to Examine Time Dependent Pile Capacity Gain

2004 ◽  
Vol 27 (6) ◽  
pp. 12191
Author(s):  
L David Suits ◽  
TC Sheahan ◽  
SG Paikowsky ◽  
EL Hajduk
Keyword(s):  
Time Dependent ◽  
Pile Capacity ◽  
Capacity Gain ◽  
Design And Construction

Dynamic analysis of a helical gear reduction by experimental and numerical methods

2020 ◽  
Vol 68 (1) ◽  
pp. 48-58
Author(s):  
Chao Liu ◽  
Zongde Fang ◽  
Fang Guo ◽  
Long Xiang ◽  
Yabin Guan ◽  
...  
Keyword(s):  
Numerical Methods ◽  
Dynamic Analysis ◽  
Dynamic Behavior ◽  
Fourth Order ◽  
Numerical Models ◽  
Helical Gear ◽  
Operating Conditions ◽  
Dynamic Responses ◽  
Lumped Mass ◽  
Gear Mesh

Presented in this study is investigation of dynamic behavior of a helical gear reduction by experimental and numerical methods. A closed-loop test rig is designed to measure vibrations of the example system, and the basic principle as well as relevant signal processing method is introduced. A hybrid user-defined element model is established to predict relative vibration acceleration at the gear mesh in a direction normal to contact surfaces. The other two numerical models are also constructed by lumped mass method and contact FEM to compare with the previous model in terms of dynamic responses of the system. First, the experiment data demonstrate that the loaded transmission error calculated by LTCA method is generally acceptable and that the assumption ignoring the tooth backlash is valid under the conditions of large loads. Second, under the common operating conditions, the system vibrations obtained by the experimental and numerical methods primarily occur at the first fourth-order meshing frequencies and that the maximum vibration amplitude, for each method, appears on the fourth-order meshing frequency. Moreover, root-mean-square (RMS) value of the acceleration increases with the increasing loads. Finally, according to the comparison of the simulation results, the variation tendencies of the RMS value along with input rotational speed agree well and that the frequencies where the resonances occur keep coincident generally. With summaries of merit and demerit, application of each numerical method is suggested for dynamic analysis of cylindrical gear system, which aids designers for desirable dynamic behavior of the system and better solutions to engineering problems.

DYNAMIC BEHAVIOR OF TELESCOPIC CRANES BOOM

2013 ◽  
Vol 13 (01) ◽  
pp. 1350010 ◽  
Author(s):  
IOANNIS G. RAFTOYIANNIS ◽  
GEORGE T. MICHALTSOS
Keyword(s):  
Dynamic Response ◽  
Dynamic Analysis ◽  
Dynamic Behavior ◽  
Analytical Model ◽  
Constant Velocity ◽  
Steel Beam ◽  
Continuum Approach ◽  
Theoretical Formulation ◽  
Modal Superposition ◽  
Superposition Technique

Telescopic cranes are usually steel beam systems carrying a load at the tip while comprising at least one constant and one moving part. In this work, an analytical model suitable for the dynamic analysis of telescopic cranes boom is presented. The system considered herein is composed — without losing generality — of two beams. The first one is a jut-out beam on which a variable in time force is moving with constant velocity and the second one is a cantilever with length varying in time that is subjected to its self-weight and a force at the tip also changing with time. As a result, the eigenfrequencies and modal shapes of the second beam are also varying in time. The theoretical formulation is based on a continuum approach employing the modal superposition technique. Various cases of telescopic cranes boom are studied and the analytical results obtained in this work are tabulated in the form of dynamic response diagrams.

Dynamic Behavior of Aircraft Wings Modeled as Doubly-Tapered Composite Thin-Walled Beams

1999 ◽  
Author(s):  
Sungsoo Na ◽  
Liviu Librescu
Keyword(s):  
Composite Materials ◽  
Free Vibration ◽  
Dynamic Response ◽  
Dynamic Behavior ◽  
Transverse Shear ◽  
Dynamical Behavior ◽  
Time Dependent ◽  
Aircraft Wings ◽  
Helicopter Blades ◽  
Thin Walled

Abstract A study of the dynamical behavior of aircraft wings modeled as doubly-tapered thin-walled beams, made from advanced anisotropic composite materials, and incorporating a number of non-classical effects such as transverse shear, and warping inhibition is presented. The supplied numerical results illustrate the effects played by the taper ratio, anisotropy of constituent materials, transverse shear flexibility, and warping inhibition on free vibration and dynamic response to time-dependent external excitations. Although considered for aircraft wings, this analysis and results can be also applied to a large number of structures such as helicopter blades, robotic manipulator arms, space booms, tall cantilever chimneys, etc.

Improving the Predictability of Hiley Pile Driving Formula in the Quality Control of the Pile Foundation

2011 ◽  
Vol 261-263 ◽  
pp. 1292-1296
Author(s):  
Hamayon Tokhi ◽  
Gang Ren ◽  
Yi Min Xie
Keyword(s):  
New Technologies ◽  
Dynamic Testing ◽  
Poor Performance ◽  
Pile Driving ◽  
Testing Methods ◽  
Pile Capacity ◽  
Equation Analysis ◽  
Pros And Cons ◽  
Recent Method ◽  
Major Factors

Pile Dynamic Formulas are the oldest and frequently used method to determine bearing capacity of piles. The more recent method is based on the Wave Equation analysis and different formulations such as Case Mathod, TNO, CAPWAP and TEPWAP which were developed for pre-driving analysis and post-driving measurements applications. The major factors for the common use of the dynamic formulas have been due to their simplicity, cost effectiveness and applicability in various piling situations. However, in some literature the energy approach have been given an unfair reputation as being unreliable and less accurate than the more analytical or dynamic testing methods. One of the issues due to the poor performance of the dynamic formulas is that, historically, the hammer energy and the energy trasferred to pile had to be assumed. Nevertheless, with the advent of computers, new technologies are emerging with the advancement in construction industry. This has produced gradual improvements that have resulted in the dynamic method to be used on many projects with greater reliability. In this paper, a review of the different testing methods as well as pros and cons of the pile driving formulas are discussed. Also, an approach to improving the widely used Hiley dynamic equation is presented. This approach enables evaluation of the pile capacity to be made more accurately.

scholarly journals Dynamic Analysis of Composite Rotors

1996 ◽  
Vol 2 (3) ◽  
pp. 179-186 ◽  
Author(s):  
S. P. Singh ◽  
K. Gupta
Keyword(s):  
Stability Analysis ◽  
Dynamic Analysis ◽  
Case Studies ◽  
Dynamic Behavior ◽  
Beam Theory ◽  
Interesting Case ◽  
Layerwise Theory ◽  
Inertia Effects ◽  
Fluid Film Bearings ◽  
Equivalent Modulus

An outline of formulation based on a layerwise beam theory for unbalance response and stability analysis of a multi mass, multi bearing composite rotor mounted on fluid film bearings is presented. Disc gyroscopics and rotary inertia effects are accounted for. Material damping is also taken into account. The layerwise theory is compared with conventionally used equivalent modulus beam theory. Some interesting case studies are presented. The effect of various parameters on dynamic behavior and stability of a composite rotor is presented.

Dynamic Analysis of Elastic Beam-Like Mechanism Systems

1989 ◽  
Vol 111 (4) ◽  
pp. 626-629
Author(s):  
W. Ying ◽  
R. L. Huston
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Behavior ◽  
Cantilever Beam ◽  
Equations Of Motion ◽  
Elastic Beam ◽  
Order Perturbation ◽  
First Order ◽  
Geometric Stiffness ◽  
Stiffness Matrices ◽  
First Order Perturbation

In this paper the dynamic behavior of beam-like mechanism systems is investigated. The elastic beam is modeled by finite rigid segments connected by joint springs and dampers. The equations of motion are derived using Kane’s equations. The nonlinear terms are linearized by first order perturbation about a system balanced configuration state leading to geometric stiffness matrices. A simple numerical example of a rotating cantilever beam is presented.

Lateral and Longitudinal Dynamic Behavior and Control of Moving Webs

1993 ◽  
Vol 115 (2B) ◽  
pp. 309-317 ◽  
Author(s):  
G. E. Young ◽  
K. N. Reid
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Behavior ◽  
Dynamic Systems ◽  
Pivotal Role ◽  
Historical Perspectives ◽  
Longitudinal Dynamic ◽  
Primary Direction ◽  
And Control ◽  
Measurement And Control

A web refers to any material in continuous flexible strip form which is either endless or very long compared to its width, and very wide compared to its thickness. This paper discusses the dynamic analysis and control of the lateral and longitudinal motions of a moving web which correspond to fluctuations perpendicular and parallel, respectively, to the primary direction of web transport. Historical perspectives are provided, from the early work of Osborne Reynolds in the late 1800s to current research. An overview of the control of both lateral and longitudinal web motion, which includes the control of tension, is presented. Present limitations in understanding and controlling lateral and longitudinal web behavior are discussed. The Journal of Dynamic Systems, Measurement, and Control has played a pivotal role in the advancement of research in this area.

Sign in / Sign up

Export Citation Format

Share Document