Evaluation of the allowable axial bearing capacity of a single pile subjected to machine vibration by numerical analysis

Ik Soo Ha,Jin-Tae Han

doi:10.1186/s40703-016-0036-5

Abstract

The purpose of this study is to analyze the changes in the vertical load of the pile when the additional vibration load due to mechanical vibration acted to the single pile supporting a vibration machine, and to review the validity of the typical calculation method for the axial bearing capacity of a single pile supporting the vibration machine by numerical analysis. Firstly, the 3D numerical model for the load–displacement behavior of a single pile was constituted. After the model was statically loaded to the allowable load in static analysis, the axial vibration due to machine vibration was added to the pile top in dynamic analysis. In these procedures, the static analysis was verified with the centrifuge test results for a single pile. Based on the analysis results, it was found that the additional dynamic load caused by machine vibration is about 6% of the allowable static load. It was thought that the design concepts of the machine foundation, assuming that the additional dynamic load due to machine vibration equals to 50% of the static load in current code, is excessively conservative.

Highlights

As the demand of plant constructions and extensions are increased, it is trend that the construction demands of the vibration machine foundation forming the basis of plant facilities are being increased
In this study, in order to examine the validity of the calculation method of the axial bearing capacity of a single pile supporting the vibration machine that is applying in conventional practice, 3D dynamic numerical analysis was performed
As a pre-procedure for evaluating the effects of mechanical vibration applied to the single pile, it was confirmed that the numerical model has the validity through the comparison with the analytical solution in simple condition

Summary

Introduction

As the demand of plant constructions and extensions are increased, it is trend that the construction demands of the vibration machine foundation forming the basis of plant facilities are being increased. Due to the vertical and horizontal vibration load generated on a vibration machine, the imbalance load is acted on the foundation Structure supporting the vibration machine and it causes the additional dynamic load. In consideration of the dynamic load generated, the design of the machine foundation is performed in the course of the following two steps. Calculate the natural frequency and displacement of the machine foundation system subjected to the vibration load by dynamic load to avoid resonance, and design to satisfy the allowable displacement given from the machine manufacturer. The strength, stability and ground bearing capacity of the Machine foundation based on static load are evaluated, and in this case, the pseudo-static design considering the additional dynamic load is made up. Because the vibration machine foundation has very small amplitude, most of the studies have been performed with respect to the soil-spring-damper

Objectives

Findings

Conclusion