Precast Piles Research Articles

Performance of combined pile foundations under a horizontal load

Laws governing formation of the stress–strain state of a "horizontally loaded foundation/ bed" system are examined. Results of experimental investigation of combined foundations with inclined precast piles sunk into a tamped-in pit are presented, and proposals are given for formulation of a computational scheme.

Parameters Analysis on Construction Control of Precast Piles in Soft Soil Ground

Based on the precast pile foundation field test of the power plant, the distribution and dissipation of the excess pore water pressure induced by the construction of the precast pile are first analyzed after the plastic drain board driven in the soft ground. Then the influence factors of the distribution and dissipation of the excess pore water pressure are presented. Subsequently the quality problem of the pre-date driven pile caused by the construction of the precast pile is studied. The main control parameters of the precast pile construction under the complicated condition are provided, which will provide a reference for such similar projects.

Research on Water-Stop System of HZM Bridge Precast Pile Cap Installation

Hong Kong-Zhuhai-Macao Bridge (HZM Bridge) is located in the LingDing Sea area outside the Pearl River estuary, where the hydrological and meteorological are very complex. Because the effective operating time was short and environmental protection requirements were high, the bridge construction is very difficult. For this feature, the method of non-navigable pier construction was used factory prefabrication and on-site installation. Unlike the traditional way of the bridge pier construction, this method can greatly shorten the time to operations at sea, by which all piers will be prefabricated in the factory and these will be only installed at the on-site. The construction of water stop between precast cap and steel pipe pile is the key aspects, and also one of the main focuses. This article introduces the water-stop system selection, design and test etc. three aspects.

Research on Soil Deformation due to Pile Jacking in Saturated Soil

According to the theoretical formula of compacting displacement field due to jacked pile in semi-infinite soil, calculation of displacement field produced during construction process of precast pile was carried out. And the changing trends of radial displacement with depth of pile penetrating, the maximum radial displacement with normalized distance r/D and vertical surface displacement with normalized distance r/D were analyzed in this paper. Then the Comparison between theory calculation results and the field test data was presented. The results show that the theoretical formula will fit with the actual situation of the site, when the soft soil properties around the pile are homogeneous and saturated. The further solving of compacting displacement field due to pile jacking was put forward.

Measured and Predicted Response of a New Jetted and Grouted Precast Pile with Membranes in Cohesionless Soils

AbstractWith increased urbanization, deep foundation (bridges, signage, walls, etc.) selection is moving toward the minimization of disturbance and installation time, as well as addressing quality control and assurance issues. Unfortunately, many types of deep foundations involve noise and vibration during installation (e.g., driven piles) or integrity and reduced resistance issues (e.g., drilled shafts, both conventional and post grouted tip, continuous flight auger piles). This paper presents a new foundation type, a jetted and grouted precast pile, which uses the advantages of several proven deep foundation installation techniques. The installation of the new pile is comprised of three distinct phases: (1) pressurized water-jetting of a precast pile into the ground; (2) side grouting of the pile; and (3) tip grouting. The pile has two separate side grouting zones, each with its own grout delivery system. Each grout zone is covered with a semirigid membrane, which results in radial expansion of the soil...

The Combined Guiding Hole Technology of Large Diameter DTH Hammer and Long Screw-Pile Driver

From an engineering reality, in order to solve complex stratigraphic drilling problems and improve construction efficiency, the method of combination of large diameter DTH hammer and the pile driver with a special long spiral drill multifunctional is proposed. This method has the characteristics of simple equipment, fast, effective, low cost etc. It can quickly drill through layers of gravel, stone, weathered bedrock, reach to depth up to above 25m. It has been widely used in embedded engineering methods of precast piles, the long spiral rock-socketed piles, piles into the rock currently. The study of this construction method has not only wide range of applications, but also has a wide range of practical and theoretical significance.

The Key Reconstruction Technology of the Changjiang Yihua Standingpile Wharf

According to the need of production and development, the coal unloading wharves of yihua harbor in the lower changjiang river need to be expanded and reconstructed. In the reconstruction, the main body can only be reinforced, not be dismounted, and the reconstruction project can not affect the unloading, so it is with great difficulty. The available plan of the reconstruction is researched and adopted. The inner force of crane girder and bridging beam is calculated by using the theory of elasticity support continuous beam. The piles are assigned with reason, the differential settlement between the new and the old building is nearly eliminated, and the bearing condition of the main structure is improved. So it is needless to carry through driving pile over water or subbottom reinforcing pile foundation under the cross frame of the former wharf . The key technology is boring a pile driving hole in added pile position on the wharf deck of the crane girder side, then to drive the precast piles through the hole on the deck of the wharf with the land vibrating pile driver. The strict restrict of driving piles on the water avoided, at the same time, the coal unloading is not affected. Pile driving on the wharf deck less difficult condition than that one on the water. The practice indicated that this methods is reliable. So it has great guidance meaning to the similar wharf reconstruction project, especially as some ones in which the bearing capacity of the piles can not meet the need under the cross bend frame.

Application of a distributed optical fiber sensing technique in monitoring the stress of precast piles

Due to its ability in providing long distance, distributed sensing, the optical fiber sensing technique based on a Brillouin optical time domain reflectometer (BOTDR) has a unique advantage in monitoring the stability and safety of linear structures. This paper describes the application of a BOTDR-based technique to measure the stress within precast piles. The principle behind the BOTDR and the embedding technique for the sensing optical fiber in precast piles is first introduced, and then the analysis method and deformation and stress calculation based on distributed strain data are given. Finally, a methodology for using a BOTDR-based monitoring workflow for in situ monitoring of precast piles, combined with a practical example, is introduced. The methodology requires implantation of optical fibers prior to pile placement. Field experimental results show that the optical fiber implantation method with slotting, embedding, pasting and jointing is feasible, and have accurately measured the axial force, side friction, end-bearing resistance and bearing feature of the precast pile according to the strain measuring data.

The Test Study to the Changes of Excess Pore Water Pressure during Precast Pile Construction

The construct to precast pile in thick clayey soil can cause the accumulation of excess pore water pressure. The high excess pore pressure can make soil, buildings and pipes surrounded have large deflection, even make them injured. Combining with actual projects, this paper presents an in-situ model test on the changes of excess pore water pressure caused by precast pile construct. It is found that the radius of influence range for single pile driven is about 15m，the excess pore water pressure can reach or even exceed the above effective soil pressure, and there are two relatively stable stages.

The Combined Guiding Hole Technology of Large Diameter DTH Hammer and Long Screw-Pile Driver

From an engineering reality, in order to solve complex stratigraphic drilling problems and improve construction efficiency, the method of combination of large diameter DTH hammer and the pile driver with a special long spiral drill multifunctional is proposed. This method has the characteristics of simple equipment, fast, effective, low cost etc. It can quickly drill through layers of gravel, stone, weathered bedrock, reach to depth up to above 25m. It has been widely used in embedded engineering methods of precast piles, the long spiral rock-socketed piles, piles into the rock currently. The study of this construction method has not only wide range of applications, but also has a wide range of practical and theoretical significance.

Monitoring System for Determination of Vibrations of Different Building Structures during Driving in Reinforced Concrete Pre-Cast Piles and Sheet Piles <sup></sup>

The phenomenon of vibration of buildings and other structures induced by different sources of vibrations is well known. Some of these sources are vibrohammers used to press in sheet piling, pile drivers with hydraulic hammer to drive in reinforced concrete pre-cast piles and vibroflots suspended to mobile cranes which are used to strengthen subsoil by vibroflotation technology.

Networked pseudodynamic testing of bridge pier and precast pile foundation

Using the internet-based network platform NetSLab, the seismic response of bridge pier and precast concrete pile foundation was investigated in this study. NetSLab was developed based on client/server concept along with a data model and communication protocols, and is capable of transferring control and feedback data and signals among geographically distributed laboratories or computers connected by the Internet. In this study, the bridge column was simulated numerically whereas the full-scale prestressed/precast pile model was tested physically with predetermined moment distribution along the pile model and neglecting pile group effects. The hybrid experimental results indicate that the sudden spalling of the thick concrete cover of the precast pile may cause unstable response of the bridge pier and pile foundation system under simulated earthquake loading, particularly when the bridge is subjected to near fault ground motions. The research also demonstrated the enhanced testing capabilities of the networked pseudo dynamic testing concept.

SIP공법 시공시 문제점 발생 요인 분석 및 대응 방안

현재 건설현장에서 매입말뚝공법인 SIP(Soil-cement Injected Precast pile)공법이 널리 활용되고 있다. 그러나 SIP공법 시공시 문제점 발생 요인들로 말뚝의 품질이 저하되거나 부실시공이 빈번히 발생하고 있다. 본 연구에서는 이 문제를 줄이는 방법으로 SIP공법을 중심으로 시공할 때 문제점 발생 요인 종류별로 현장 기술자들을 대상으로 설문조사를 수행하였다. 그리고 설문 분석 결과를 토대로 문제점 종류별로 자주 발생되는 문제점 요인을 분석함으로써 대응 방안을 제시하였다. 본 연구에서 제시한 문제점 요인별 대책은 향후 건설현장에서 SIP공법으로 시공할 때, 문제점을 최소화할 수 있는 효과적인 자료가 될 것으로 사료된다. Currently in construction Soil-cement Injected Precast pile of buried pile method are in wide use. But deterioration in pile quality and faulty construction can be often found these days because of problems arise in the construction field. For this study, survey was carried out by targeting construction engineers working in the field in order to identify the types and the causes of problems arise based on SIP(Soil-cement Injected Precast) method. By analyzing the causes of problems arise, countermeasures could be presented. The data and the analysis presented in the study could be effectively used for minimizing problems arise in future during SIP method construction.

Finite element study of the influence of pile jetting on load capacity of adjacent piles

A recent technique of pile installation of pre-cast piles without noise or vibration is the use of pile jetting. Water jets at high pressures are used to drive the piles that temporarily liquefy the soil thus allowing the pile to penetrate into the ground under their self-weight. This technique is utilized under conditions where control of construction induced vibration is essential, such as amidst existing structures within a city zone. Due to the excessive water velocity introduced in jetting, soil in the immediate neighbourhood is eroded thus creating a narrow water path along which eroded material is brought to the surface. This paper discusses the numerical modeling of the pile jetting process, the lateral extent of the spread of pore pressure zone around the jetted pile and the effect of pile jetting on the vertical load carrying capacity of adjacent piles. Finite element analyses were performed in two phases using ABAQUS. The results from the analyses clearly illustrate the extent of the soil zone influenced by pile jetting and the influence on the load carrying capacity of the adjacent piles.

Effect of Steam Curing on Concrete Piles with Silica Fume

Silica fume is a common addition to high performance concrete mix designs. The use of silica fume in concrete leads to increased water demand. For this reason, Florida Department of Transportation (FDOT) allows only a 72-hour continuous moist cure process for concrete containing silica fume. Accelerated curing has been shown to be effective in producing high-performance characteristics at early ages in silica-fume concrete. However, the heat greatly increases the moisture loss from exposed surfaces, which may cause shrinkage problems. An experimental study was undertaken to determine the feasibility of steam curing of FDOT concrete with silica fume in order to reduce precast turnaround time. Various steam curing durations were utilized with full-scale precast prestressed pile specimens. The concrete compressive strength and shrinkage were determined for various durations of steam curing. Results indicate that steam cured silica fume concrete met all FDOT requirements for the 12, 18 and 24 hours of curing periods. No shrinkage cracking was observed in any samples up to one year age. It was recommended that FDOT allow the 12 hour steam curing for concrete with silica fume.

DEVELOPMENT OF PRODUCTIVE SYSTEM UTILIZING STEEL BEAM-PRECAST PRC PILE AND SURFACE SOIL IMPROVEMENT

Authors developed productive system utilizing pre-cast PRC piles, which system is the one-story buildings limitation. On this system pile are driven into the under soil upto the over ground, and integrated columns of the first floor. We can reduce environmental load, particularly since this system can omit footings and foundation garter, that are consequent on soil disposal for earth work, and material consumption for concreting such as reinforcement and formwork.

Experimental behavior and design of a new kinematic isolator

This paper reports on the experimental behavior and design of a rolling self-centering precast prestressed pile (PPP) isolator. This isolation device was developed as an alternative for use in light-weight and low-cost housing located in sites with poor soils. The specimens tested had a spherical and flat–spherical top and bottom end rolling surfaces, respectively, and they generate the self-centering action by a prestressed central cable. Eight full-scale PPP specimens were tested, including two with yielding reinforcement bars at the rolling interface. The axial load on the tested specimens was constant and equal to 147.2 kN, which corresponds to a typical vertical load on a PPP for the types of building considered in this research. The experimental results validate in general the predictions of the analytical model presented; however, the theoretical model is not able to predict the energy dissipation observed in specimens without passive reinforcement, and the apparent larger initial flexibility in the element force–displacement relationship. Additionally, a procedure is developed for simplified isolation design of light-weight structures, which combines the use of flat–spherical PPPs and steel–Teflon sliders in parallel. As an example, the procedure was tested on a design alternative for a low cost housing complex built under conventional fixed-to-base foundations.

Resistance characteristics of soils in the beds of precast piles

Results are presented for experimental studies of the stress-strain state of soils in the beds of precast piles during their installation, and as they receive static loads. Laws governing phenomena that occur in the soils, which define the settlement of the piles and their bearing capacity, are established.

Three‐dimensional behavior of a spherical self‐centering precast prestressed pile isolator

AbstractA 3D analytical formulation of a precast prestressed pile (PPP) seismic isolator with top and bottom spherical rolling kinematic constraints is proposed. The PPP isolator was initially conceived as a low‐cost seismic isolation (and foundation) system for housing units of low‐income people. Since these structures are usually located at sites with poor soil conditions, the PPP isolator also works as a foundation pile by connecting the superstructure with more competent soil layers. The non‐holonomic nature of the rolling constraint is dealt with by a structural formulation. The proposed 3D formulation is validated by numerical results obtained from a previously proposed formulation for the 2D problem, and a contact finite element model in ANSYS (www.ansys.com). Other issues associated with the dynamic response of isolated structures with the PPP are also examined, such as expected response reductions, variation in the axial force of the central prestressed cable, and torsional response amplifications. Finally, guidelines to estimate the actual 3D response using 2D analysis results are investigated. Copyright © 2009 John Wiley & Sons, Ltd.

Foundations for Integral Abutments

Integral-abutment bridges have many advantages over full-height-abutment or stub-abutment bridges. Integral abutments eliminate or reduce the number of expansion joints in bridge superstructures and simplify design, detailing, and construction. In this paper, foundation design concepts, such as fixed-head pile, pinned-head pile, hinged abutment, fixed-base pile, prebored hole, sleeved pile, and asymmetry are reviewed. The typical foundation type for support of integral abutments is the steel H pile. Depending on bridge length, skew, and site conditions, other types of foundations, such as precast prestressed-concrete pile, pipe pile (steel encased concrete pile or metal shell pile), timber pile, combined H pile (or W section) and drilled shaft, caisson wall, drilled shaft, sheet pile, and spread footing can be used to support integral abutments. Several design methods and proposed limits for typical integral abutment bridges are reviewed.