New Horizons in Piling

Development and Application of Press-in Piling

Malcolm D. Bolton, Akio Kitamura, Osamu Kusakabe, Masaaki Terashi

• Publisher: CRC Press
• Year: 2021
• Print ISBN: 9780367546526
• eBook ISBN: 9781000297720
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Civil Engineering
• Index: Technology & Engineering

The piling industry has, in recent years, developed a variety of press-in piling technologies with a view to mitigate noise & vibration nuisance. This book focuses on the "Walk-on-Pile" type press-in piling system, which offers an alternative engineering solution for piling works. This type of piling has unique features, including the application of the compact piling machine using pre-installed piles as a source of reaction force to jack in a new pile by hydraulic pressure. Moreover, the machine can walk along the top of piles already installed, thus enabling piling in a limited space and headroom with minimum disruption to social functions and services of existing infrastructure. These features are opening up a new horizon in piling, leading to novel application of embedded walls previously considered impossible.

This introductory book provides a historical development of press-in piling and various challenging applications worldwide as well as scientific research outcomes, forming a valuable source of reference for readers who are unfamiliar with press-in piling, including project owners, design engineers, practical engineers as well as researchers and students.

Chapter 1

Introduction

1.1 Embedded structures

The Great East Japan Earthquake with a moment magnitude (M) of 9.0 occurred along a subduction zone in the Pacific Ocean on March 11, 2011, and the earthquake triggered enormous tsunami disasters as shown in Figure 1.1. The maximum height of over 21 m was recorded at Fukushima Prefecture. Intensive investigation of damage to structures demonstrates significant advantages of embedded structures over gravity-type structures against tsunami disasters.

Figure 1.1 Tsunami disasters caused by the Great East Japan Earthquake. (a) Wave overtopping (the Mainichi photobank). (b) Stranded vessel.

A typical gravity-type structure is a breakwater caisson constructed on a rubble mound, as illustrated in Figure 1.2.

Figure 1.2 Typical breakwater caisson on a rubble mound.

Figure 1.3 is a view of the failed caisson-type breakwater constructed on a rubble mound in Kamaishi Port, of which the depth is −63 m, the Deepest Breakwater according to Guinness World Records. Twelve out of 22 caissons were damaged.

Figure 1.3 A view of failed breakwater in Kamaishi Port. (Tohoku Regional Development Bureau, MLIT Japan).

Gravity-type structures must meet three stability requirements: (i) stability of vertical bearing capacity, (ii) sliding stability, and (iii) overturning moment stability. The situation may be idealized as a footing with a width of B resting on the ground surface subjected to combined loads of vertical load (V), horizontal load (H), and moment (M) as illustrated in Figure 1.4.

Figure 1.4 Footing subjected to combined loads.

Theoretical and experimental evidence on the failure of the footing can be summarized in a three-dimensional form of failure envelope shown in Figure 1.5. Working load conditions must be within the failure envelope for safe operation.

Figure 1.5 Failure envelope of a footing.

Tsunami flow reduces the effective self-weight of the structure due to the buoyancy force, which is generally considered to increase the safety against vertical bearing failure, although the bearing capacity may decrease to some extent when the tsunami flow generates seepage in a rubble mound. The buoyancy force, in turn, decreases frictional resistance at the base of the footing, and the tsunami flow also increases the horizontal force acting on the foreside wall of the structure due to the water level difference between the sea side and the harbor side. These two combined effects would decrease the safety against sliding failure. The tsunami flow also greatly increases the overturning moment because the moment arm from the base to the point of resultant horizontal forces becomes longer, and meanwhile the horizontal force also increases in magnitude. These resultant effects lead to a decrease in safety against overturning failure. Failure modes, therefore, may vary with the loading conditions to which the structure is subjected.

When a tsunami overflows a breakwater, it causes scouring of the mound below the structures which may then tilt or topple. Hydraulic engineers also point out that negative pressure generated on the backside of the structure under a tsunami overflow causes horizontal destabilizing forces to increase based on laboratory experiments.

Another typical example of gravity-type structure is buildings with spread foundation. A number of buildings and residential houses with spread foundations were swept away due to tsunami flows, as shown in Figure 1.6.

Figure 1.6 Overturned building with spread footing.

Figure 1.7 is a toppled four-story, steel frame building supported by a friction pile foundation consisting of pre-stressed concrete piles with a diameter of 300 mm. In Figure 1.7, it is seen that one pile is hanging from its foundation. Building engineers consider that the combined effects of buoyancy forces and horizontal forces may be the main reason for the damage. Insufficient embedment may mean that piled foundations are not sufficiently resilient against strong tsunami flows. Some geotechnical engineers suspect that soil liquefaction may have occurred prior to the arrival of the tsunami flow at this particular location, reducing the pullout resistance of the friction piles.

Figure 1.7 Toppled four-story building with pile foundation (Tamura, 2012).

However, properly embedded structures can be considered to be resilient against even a severe tsunami. The embedment effects increase the vertical bearing capacity largely due to overburden pressure, and increase the pullout resistance (negative vertical bearing capacity) due to frictional resistance along the periphery of the embedded parts of the structure. The embedment effects also increase the horizontal resistance mainly due to the mobilization of passive earth pressure on the side walls of the embedded elements of the structure. Similarly, the moment resistance increases benefitted by the mobilization of passive earth pressure as well as frictional resistance at the side walls and at the base of the structure.

Referring to the rugby ball-shaped failure envelope shown in Figure 1.5, the embedment effects significantly enlarge the size of the failure envelope and create additional pullout resistance, as illustrated in Figure 1.8.

Figure 1.8 Effect of embedment on failure envelope.

When the structure is firmly embedded, and the failure envelope becomes sufficiently large relative to working loads, an unconfined failure mechanism is virtually impossible to form and the structure behaves in a resilient manner.

Figure 1.9 is a view of a temporary double-walled cofferdam comprising two parallel rows of steel sheet piles driven into the ground and connected together by a system of tie rods at one level. The space between the walls was filled with granular materials such as sand, gravel, or broken rock. Figure 1.10 illustrates the situations before and after the tsunami, indicating about 2 m depth of erosion on the sea side.

Figure 1.9 Double-walled cofferdam with no structural damage.

Figure 1.10 Situations before and after tsunami.

As shown in Figure 1.9, no structural damage was observed either at the steel sheet piles or of the tie rods, although the upper part of the backfill materials was scoured and washed away to about 1 m depth. This example clearly demonstrates that embedded structures are resilient and have advantages over gravity-type structures against tsunami disasters. A sufficiently embedded structure may be designated an “implant structure”.

1.2 Steel as a construction material

Steel is a ductile material with high tensile strength in comparison with other major construction materials such as soil, rock, and concrete. Steel makers supply steel for a wide range of engineering applications, including civil engineering applications such as foundations, for port and harbor structures, and for forestry conservation.

Geotechnical engineers have long been familiar with U-shaped steel sheet piles for temporary retaining construction and coffering as well as permanent structures. Steel tubular piles are also widely used for civil engineering structures, such as retaining walls, foundations, port and harbor facilities, countermeasures for landslides, and more recently liquefaction countermeasures for river and coastal levees.

According to the statistics of the year 2014 published by the Japan Iron and Steel Federation, demand for steel sheet piles in Japan was as much as 597,000 tons in total, in which 361,000 tons were for permanent structures and 236,000 tons for temporary structures. Major areas of applications were forestry conservation and flood control (279,000 ton), port and harbor structures (38,000 tons), and others (44,000 tons).

Embedded structures using steel sheet piles/steel tubular piles offer resilient structures. The Japanese Association for Steel Pipe Piles and Steel Sheet Piles conducted damage investigations on structures after the Great East Japan Earthquake, covering river levees with seismic countermeasures, river revetments, road retaining structures, and cofferdams. All the structures adopted steel sheet piles. The investigation confirmed that no damage or minor damage was observed and all the structures remained sound. As demonstrated in Figure 1.9 as an example, the temporary double-walled cofferdams comprising two parallel rows of steel sheet piles survived against the Great East Japan Earthquake.

1.3 Design and construction requirements

Many developing countries with an increasing population have been experiencing urbanization at an accelerating rate. Existing urban infrastructure in these regions is insufficient to accommodate an increasing social pressure, both in terms of volume of demand and in terms of quality of de...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• List of figures
• List of tables
• Preface
• 1 Introduction
• 2 Construction by press-in piling
• 3 Innovative applications
• 4 Emerging applications
• 5 Responses of piles installed by the press-in piling
• Appendix: List of related publications
• Index