Showing papers on "Embedment published in 2001"

Ultimate lateral resistance of pile groups in sand

Abstract: Experimental investigations on model pile groups of configuration 1 1, 2 1, 3 1, 2 2, and 3 2 for embedment length-to-diameter ratios Ld 12 and 38, spacing from 3 to 6 pile diameter, and pile frict...

Concrete-Steel Composite Coupling Beams. I: Component Testing

Abstract: A viable alternative to reinforced concrete coupling beams with heavily reinforced diagonal struts is steel or steel-concrete composite beams. A limited number of previous studies have examined var...

Pull-out behaviour of steel rods bonded into timber

Abstract: Connections for timber structures using concealed bonded-in rods offer one possible solution to the development of more efficient joining methods. However the importance of certain basic joint characteristics, and the influence of adhesive type and properties, are not yet fully understood and as such design criteria are lacking. This paper describes a comprehensive experimental and numerical investigation into the fundamental material and joint geometry characteristics of rods bonded in to timber. The adhesive type and performance are both considered, along with test configuration and joint parameters that included rod embedment length, rod diameter, annular bondline thickness, multiple rods and rod spacing. A novel approach that involved end-profiling of the bond area was also investigated. It was found that epoxy adhesives out-performed all other types investigated, and pull-out strengths can be significantly improved through careful selection and optimisation of the joint geometry.

Concrete-steel composite coupling beams. ii: subassembly testing and design verification

Abstract: As shown in a companion paper, the embedment length of steel-concrete composite coupling beams inside wall piers should be computed by incorporating the contribution of the encasement. In lieu of detailed fiber-based analytical techniques, a simple design-oriented model was developed and verified through testing of additional specimens with more realistic loading and boundary conditions. Moreover, the influence of face-bearing plates and floor slab was examined. The developed design method results in longer embedment length, and significantly enhanced energy-dissipating characteristics, strength, stiffness, and ductility. Additional improvements are possible by using face-bearing plates. The contribution of floor slab toward stiffness of the coupling beam is lost at small deformations and may be ignored. Slab participation toward the strength of the steel-concrete composite coupling beams is different from that anticipated for conventionally reinforced concrete beams because of the amount of equivalent re...

Parametric study of riprap failure around bridge piers

Abstract: This paper presents a parametric study on riprap protection around a cylindrical bridge pier with uniform bed sediments. Riprap layers with different characteristic parameters: thickness, cover width, and placement level of the riprap layer; median grain size and density of the riprap stone; and undisturbed approach flow depth were tested under a sequence formation of ripples, dunes and transition flat bed. Observations show that a riprap layer will eventually degrade to a maximum level which is the same as the maximum pier scour depth when the riprap layer is not present. This study proposed a criterion to determine the maximum embedment level and the embedment velocity, i.e., the flow velocity at which the riprap layer has embedded to its maximum level. The experimental results show that variations of the characteristic parameters have no influence on the embedment failure at the upper end of the dune regime. The study also proposes a maximum embedment velocity, which defines a critical flow velocity at...

Behavior of precast, prestressed concrete pile to cast-in-place pile cap connections

Abstract: This investigation studied the capacity of square pile-to-pile cap connections where the precast-prestressed pile is simply embedded in the cast-in-place pile cap. Both experimental and analytical results are presented. It is shown that the plain embedment can develop the flexural capacity of the pile without distress to the pile cap of connection region provided that a sufficient embedment length is furnished. Equations for determining the required embedment length are provided. For design purposes, it is recommended that a plain embedment length equal to the width of the embedded pile be used.

An Experimental Study of Seismic Bearing Capacity of Shallow Footings

Abstract: In this paper, the results of an experimental investigation on the response of model shallow footings to horizontal accelerations are presented. The experiments were conducted on square and rectangular footings resting on or embedded in a dry sand and shaken in a shake box. The shake box was designed to subject the soil to simple shear conditions during shaking. Model footings, constructed f?om lead, were used to study the seismic bearing capacity. The influence of the magnitude and frequency of the horizontal accelerations, the static bearing capacity safety factor, the footing shape, the depth of embedment, and the relative density of the soil on the seismic bearing capacity were investigated. It is shown that the initial shear fluidization acceleration is the maximum acceleration sustainable by a shallow footing regardless of the static bearing capacity safety factor. Critical accelerations from limit equilibrium analyses do not compare favorably with the experimental results except when the change in angle of friction from cyclic densification was taken into account.

Method of making magnetic recording medium utilizing die

Abstract: A non-magnetic substrate for a magnetic recording medium is formed or molded within a die. The die is designed to define embedment depressions on the surface of the resulting non-magnetic substrate. Any bumps or lugs formed on the inner surface of the die can be employed to form the embedment depressions on the non-magnetic substrate. A magnetic material fills the individual embedment depression so as to establish a magnetic block embedded into the surface of the non-magnetic substrate. The magnetic block can be utilized as a positional mark in a tracking servo control for a corresponding read/write head in a magnetic storage system.

Guidance for design of suction caissons against buckling during installation in clay soils

Abstract: Suction caissons are a type of foundation which are penetrated into the seabed using net external water pressure, rather than more conventional techniques. The geometry of these foundations is such that, structurally, they fall into the category of shell structures. Due to the type of loading experienced by these foundations, which is predominantly hydrostatic, buckling of the caisson shell during suction installation becomes a consideration. This paper examines the factors influencing the buckling load of the caisson, including the boundary conditions of the shdl, geometric imperfections, material plasticity, embedment ratio and the amount of lateral restraint offered by the surrounding soi l Results are obtained from three dimensionai finite dement analyses.

Wave-soil-pipe coupling effect on submarine pipeline on-bottom stability

Abstract: Wave-soil-pipe coupling effect on the untrenched pipeline stability on sands is for the first time investigated experimentally. Tests are conducted in the U-shaped water tunnel, which generates an oscillatory how, simulating the water particle movements with periodically changing direction under the wave action. Characteristic times and phases during the instability process are revealed. Linear relationship between Froude number and non-dimensional pipe weight is obtained. Effects of initial embedment and loading history are observed. Test results between the wavesoil-pipe interaction and pipe-soil interaction under cyclic mechanical loading are compared. The mechanism is briefly discussed. For applying in the practical design, more extensive and systematic investigations are needed.

Composite segment in pipe embedment method

Abstract: PROBLEM TO BE SOLVED: To provide a lightweight, easily handling, and inexpensive segment as a tunnel lining material having strength endurable even against a load of a deep burying position while reducing a cost so as to be capable of maintaining the strength only a short period up to integrating a filler and a pipe in a pipe embedment method for filling the filler in a void part between a tunnel inner wall and the pipe after laying the pipe in a tunnel. SOLUTION: A slim lining frame body 2 having the rising edge is arranged on the respective sides of a steel material skin plate 1 curved in the peripheral direction. The rising edge of peripheral directional both side parts of this frame body 2 is formed of main stringer boards 3 and 3, and the rising edge of both end parts of this frame body 2 is formed of joint plates 4 and 4, and a rib is not arranged at all between the mutual main stringer boards 3. A partition plate 6 is arranged in the inside peripheral directional almost center of the slim lining frame body 2. Main reinforcements 7 and distribution reinforcements 8 are arranged inside this slim lining frame body 2, and concrete 11 is filled to form a reinforced steel frame concrete structure.

Seal-Slab Prestressed Pile Interface Bond from Full-Scale Testing

Abstract: In this paper, experimental results are presented from a study conducted to assess the interface bond between a cast-in-place concrete seal slab and prestressed concrete piles in cofferdams. Three different seal slab placement conditions (fresh water, salt water, and bentonite slurry) were evaluated with results compared against controls where no fluid had to be displaced by the concrete. Normal pile surfaces were also studied. Additionally, the situation of soil-caked piles was also investigated. Both model and full-scale tests were conducted. In the model tests, 28 15-cm sq. prestressed sections were used with the embedment depth varied between d and 2d, where d is the width of the pile. 16 specimens were tested in the full-scale tests. The prestressed piles were 36 cm sq., with the emdbedment varied between 0.5 and 2d. Four of the 16 piles were cast with embedded gages located at the top, middle, and bottom of the interface region. The results show that loads were transferred to the piles over an effective area, not the entire embedded depth. Significant bond stresses developed even for the worst placement condition. Recommendations are made for revising current values in specifications.

Limit States and Factor of Safety in Design of an Anchored Sheet Pile Wall

Abstract: Factors of safety in the traditional design of anchored sheet pile walls have been introduced in a variety of ways. Furthermore, empirical and semiempirical factors are used to modify the calculated depth of embedment, anchor rod force, and maximum bending moment in sheet piling. This leads to a range of designs within the traditional allowable stress design (ASD) approach. Even in the new ultimate limit states design (LSD) method, two approaches are available. One approach is to use load and resistance factor design (LRFD), and the other is to use partial safety factors on the material properties in combination with load factors. In view of the number of design alternatives available, a calibration study of LSD with ASD for an anchored bulkhead was performed. The practical problem of a steel sheet pile wall in a layered cohesionless soil and cohesionless soil overlying cohesive soil was analyzed. The depth of embedment, the anchor rod force, and the maximum bending moment in sheet piling were determined ...

Empirical models depicting grain angle effects on load-embedment response of dowel-type fasteners in wood

Abstract: Predicting the moment-rotation response of a multifastener timber joint requires the use of empirical models that describe adequately the influence of load-to-grain angle on embedment response of wood under a dowel fastener. This paper presents two models. The first model describes the relationship between load, embedment, and load-to-grain angle, and can be used for predicting moment-rotation response of a multifastener joint. The second model relates the ultimate embedment at failure to load-to-grain angle. This second model is intended for predicting failure of timber joints. Comparison with test data confirms the suitability of these models to describe the influence of load-to-grain angle on embedment response of wood.

Foundation form and manufacturing method thereof

Abstract: PROBLEM TO BE SOLVED: To provide a foundation form made totally labor-saving from the manufacture of a panel to the embedment of an anchor bolt in view of the insufficient labor-saving effect of a conventional connecting type form such as requiring much labor to manufacture it. SOLUTION: In this foundation form, concrete panels 10a, 10b facing each other are connected by a pipe 4 projected from the side faces and made solid with concrete 12. The pipe 4 is jointed at both ends to reinforcing members 2 for the concrete panels, and form members forming the faces of the concrete panels are disposed without clearance to the surface of the pipe 4 to place concrete.

Stress-Strain State of Pile Beds Tested under a Static Loading

Abstract: The stress-strain state of the beds of prismatic piles subjected to static testing is analyzed, and the influence exerted by the distance between test and anchor piles and the depth of their embedment on the stress-strain state of the soil is examined.

Influence of specific gravity on embedment gaps in metal-plate-connected truss joints

Abstract: Gaps that occur between the lower surface of a metal truss plate and the wood surface can significantly reduce connection lateral resistance. This project examined the variability of embedment gap as a function of specific gravity (SG) and developed predictive equations for quantifying the influence of embedment gap on joint strength. Two plate-to-load orientations were tested and analyzed. Southern pine truss joints were prepared from lumber having a wide range of SG. Embedment gap was not artificially controlled but occurred as a natural aspect of joint fabrication. It was found that embedment gap weakly correlated with SG for the LRAA (r2 = 0.3089) and LREA (r2 = 0.3659) orientations. The variability in predicted embedment gap did not increase with increased SG for the LREA orientation while for the LRAA orientation the variability in predicted embedment gap did increase. For both orientations, it was apparent that lower SG specimens exhibited an increased potential for no embedment gap. For specimens with no embedment gap, a lower coefficient of variation (COV) in lateral resistance may be possible but would have to be researched further. A lower COV in lateral resistance for joints with no embedment gap may justify lowering the 3.2 safety factor currently employed.

Uplift Resistance of Post Foundations

Abstract: Forty-five post foundations were withdrawn from a sandy soil to determine the relative strength of different anchorage systems. During these tests, the addition of two 1.5 x 3.5 x 10 inch blocks at a depth near 4 feet increased uplift resistance 4200 lbf. Prehydrated concrete collars with 19-inch diameters provided uplift resistances in excess of 22,000 lbf when embedded to a depth of 50 inches. Dry concrete mix, when buried, was found to undergo significant self-hydration, producing concrete collars with an average compressive strength greater than 2000 lbf/in 2 after an embedment time of only six weeks.

Nondestructive determination of unknown pile tip elevations using modal analysis

Abstract: A comprehensive experimental study and three corresponding numerical analyses were conducted to investigate the suitability of a modal analysis approach for identification of unknown pile embedment lengths. A small-scale pile facility containing partially embedded piles of differing lengths, cross section dimensions, and encasement attributes was constructed so that experimental pile response data could be gathered in a controlled laboratory environment. Impact tests were performed at a number of locations on each model pile, and the modal parameters for each were estimated from the resulting frequency response function data. Comparison of modal parameters estimated from model piles with similar cross section dimensions and different buried lengths showed essentially no variation in natural frequency as the buried length increased, in the frequency range that was practical to measure. Modal damping values showed a greater variation with pile embedment depth, but no discernable trends were apparent that wo...

Method for erecting pole signboard

Abstract: PROBLEM TO BE SOLVED: To reduce the cost required for erection of a pole signboard. SOLUTION: This method for erecting the pole signboard consists in inserting the base end of a pole 1a of the pole signboard 1 into a vertical hole 5 for embedment formed by being excavated to a suitable depth from the ground surface, then packing concrete 3 into the space part appearing between the outer periphery of the base end of the pole 1a and the inner periphery of the vertical hole 5 for embedment and erecting the pole 1a by solidification of the packed concrete 3. One such method is to insert the base end of the pole 1a into the vertical hole 5 for embedment in the state of mounting a self- standing assisting member 10, which prohibits the inclination of the pole 1a before the solidification of the concrete 3 packed into the space part to the base end of the pole 1a.