Showing papers on "Embedment published in 2003"

Investigation of bond in concrete structures strengthened with near surface mounted carbon fiber reinforced polymer strips

Abstract: Fiber reinforced polymer (FRP) materials are currently produced in different configurations and are widely used for the strengthening and retrofitting of concrete structures and bridges. Recently, considerable research has been directed to characterize the use of FRP bars and strips as near surface mounted reinforcement, primarily for strengthening applications. Nevertheless, in-depth understanding of the bond mechanism is still a challenging issue. This paper presents both experimental and analytical investigations undertaken to evaluate bond characteristics of near surface mounted carbon FRP (CFRP) strips. A total of nine concrete beams, strengthened with near surface mounted CFRP strips were constructed and tested under monotonic static loading. Different embedment lengths were used to evaluate the development length needed for effective use of near surface mounted CFRP strips. A closed-form analytical solution is proposed to predict the interfacial shear stresses. The model is validated by comparing t...

Three-Dimensional Lower Bound Solutions for Stability of Plate Anchors in Clay

Abstract: Soil anchors are commonly used as foundation systems for structures that require uplift or lateral resistance. These types of structures include transmission towers, sheet pile walls, and buried pipelines. Although anchors are typically complex in shape (e.g., drag or helical anchors), many previous analyses idealize the anchor as a continuous strip under plane strain conditions. This assumption provides numerical advantages and the problem can be solved in two dimensions. In contrast to recent numerical studies, this paper applies three-dimensional numerical limit analysis to evaluate the effect of anchor shape on the pullout capacity of horizontal anchors in undrained clay. The anchor is idealized as either square, circular, or rectangular in shape. Estimates of the ultimate pullout load are obtained by using a newly developed three-dimensional numerical procedure based on a finite-element formulation of the lower bound theorem of limit analysis. This formulation assumes a perfectly plastic soil model with a Tresca yield criterion. Results are presented in the familiar form of break-out factors based on various anchor shapes and embedment depths, and are also compared with existing numerical and empirical solutions.

Analysis of load-slip characteristics of nailed wood joints: application of a two-dimensional geometric nonlinear analysis

Abstract: We used a two-dimensional finite element method to analyze the load-slip characteristics of nailed wooden joints sheathed with a panel. We used tests of nail bending, nail shank embedment in a wood or a panel, nail-head embedment in a face of a panel, nail withdrawing from a wood, friction between a wood and a panel, and initial axial forces of the nails. The values of the material properties for the analytical models were determined with the above tests. With a conventional one-dimensional analysis it is impossible to evaluate the shearing performance accurately because the axial forces of the nail are not calculated. Therefore, we used two-dimensional geometric nonlinear analysis. The computed load-slip curves closely matched the original experimental results; and when the friction and initial axial forces were considered, the computed curves were more likely to match the original experimental results. Our results suggested that it is better to use geometric nonlinear analysis to analyze the shearing characteristics of nailed joints, and that friction and axial forces are important factors for accurate analysis.

Embedment device for fiber-enhanced slurry

Abstract: An embedment device for use in a structural panel production line wherein a slurry is transported on a moving carrier relative to a support frame, and chopped fibers are deposited upon the slurry, includes a first elongate shaft secured to the support frame and having a first plurality of axially spaced disks, a second elongate shaft secured to the support frame and having a second plurality of axially spaced disks, the first shaft being disposed relative to the second shaft so that the disks intermesh with each other. The intermeshing relationship enhances embedment of the fibers into the slurry and also prevents clogging of the device by prematurely set slurry particles.

Digital watermark-embedding apparatus and method, digital watermark-detecting apparatus and method, and recording medium

Abstract: A digital image signal is divided into blocks. Each of the divided blocks is subjected to orthogonal transformation. As a result, the divided blocks are transformed into several frequency components. One or more frequency components are selected in accordance with a characteristic amount that is extracted from the several frequency components. Values of the selected frequency components are operated under a predetermined rule in accordance with an embedment signal that is generated from embedment information.

Method for embedding and extracting digital watermark on lowest wavelet subband

Abstract: Disclosed is a method for embedding a digital watermark on a wavelet lowest subband. The method including: setting a DC component region of a multi-stage wavelet-transformed original copy image to a watermark embedment region, and high-frequency filtering an original picture LLn of the embedment region; generating index information for designating a pixel position, and a watermark sequence to be embedded; calculating an embedment strength λ for each position of the watermark embedment region; in case the watermark sequence is sequentially embedded on an embedded position designated by the index information, mutually comparing the original picture LLn coefficient value for each embedded position with a mirror picture LLn′ coefficient value, and then altering the original picture LLn coefficient value; and in case the original picture LLn coefficient value is differentiated above a predetermined value with reference to the corresponding embedment strength λ, skipping the watermark embedment for the position.

Experimental studies on precast prestressed concrete pile to cip concrete pile-cap connections

Abstract: Experimental and analytical studies were conducted on three full-scale precast (PC), prestressed concrete pile to cast-in-place (CIP) concrete pile-cap subassemblies having typical details used in bridges in seismic regions. Test results of two connections under constant axial load and cyclic lateral forces indicated that despite a shallow embedment of the PC pile end to the pile cap, considerable moment can be resisted by the connection. Results from testing a pile-to-pile-cap connection subjected only to cyclic axial loading revealed adequate tensile and compressive capacities. It is proposed that the moment capacity of the pile-to-pile-cap connection with shallow embedment can be calculated based on the summation of the flexural capacity of the pile end considering only the anchor dowel bars and the resistance of the embedment.

The effect of head plate details on the pull-out behaviour of headed bars

Abstract: This paper presents the pull-out behaviour of headed bars having various head details and the prediction of pull-out failure capacity governed by concrete breakout failure, reinforcing bar failure and pull-through failure. It is becoming increasingly common to anchor reinforcing bars by welding a plate to the end of the bar. This paper presents a study of the influence of the shape and thickness of the plate on the pull-out behaviour of bars anchored in this way. A total of 58 pull-out tests were conducted on four slab-like specimens and 13 beam-like specimens containing headed bars. The test variables were the reinforcing bar diameters connected to the headed plate, the head plate shapes, the dimensions of head plates and the types of welding scheme connecting the reinforcing bars and head plates. Concrete compressive strengths and embedment depths were also taken into consideration. Headed bars were manufactured with varying details of head according to ASTM 970-98 and the embedment depths were based on...

Digital watermark-embedding apparatus, digital watermark-embedding method, and recording medium

Abstract: A characteristic amount is retained and calculated from an entered video signal. Embedment intensity is retained and calculated from the retained characteristic amount. Embedment information is embedded as digital watermarks into the entered video signal in accordance with the retained embedment intensity of the previous frame or field that is located at a position earlier in time than a target image subject to digital watermark embedment. As a result, an output signal of video having the digital watermarks embedded therein is produced. The digital watermarks are embedded into the target image with reference to another image located at a position earlier in time than the target image. Such digital watermark embedment suppresses a delay in output of an output image with reference to an input image.

Experimental study of bond-slip performance between steel and concrete in src structures

Abstract: Based on the experimental study of the bond-slip behavior between steel and concrete in SRC structures, the bond-slip mechanism between steel and concrete is analyzed and several important parameters are discussed. The distribution mode of bond stress and slip along the embedment length of steel and concrete interface, as well as the bond-slip relationship between the bond force and slip are also studied, and their equations are provided. The calculating method of bond strength, slip value and bond failure load are presented. Good agreement with the experimental results is reached. According to the punching failure principle of concrete slab, a determining method for critical thickness of concrete cover is proposed. The present results are believed to be useful for further study of bond-slip relationship and bond failure criterion between steel and concrete as well as the improvement of calculating theory of strength, stiffness, deformation, crack width and finite element analysis of SRC structures.

Bond Strength of Grout-Filled Splice Sleeve Considering Effects of Confinement

Abstract: The purpose of this study is to propose the more reasonable equation of bond strength of grout-filled splice sleeve. To accomplish this objective, total 60 full-sized specimens were tested under monotonic loading. The experimental variables are compressive strength of mortar, embedment length and size of reinforcing bars. Following conclusions are obtained; 1) If the adequacy of existing equations which estimate the bond strength of grout-filled splice sleeve are investigated, they underestimate the bond strength of grout-filled splice sleeve by 8-18%. Also the existing equations have a tendency to underestimate with decrease in the embedment length of reinforcing bars. 2) From the test result of bond failure, the equation which estimates the confining pressure of grout-filled splice sleeve was proposed by making multiple regression analyses of which independent variables are embedment length of reinforcing bars and compressive strength of mortar. This equation predicted the measured bond capacity of this test more accurately than existing equations and eliminated the deviation according to the embedment length of reinforcing bars.

Apparatus, method and recoding medium for delay suppression during embedding of watermarks in video sequences

Abstract: A characteristic amount is retained and calculated from an entered video signal. Embedment intensity is retained and calculated from the retained characteristic amount. Embedment information is embedded as digital watermarks into the entered video signal in accordance with the retained embedment intensity of the previous frame or field that is located at a position earlier in time than a target image subject to digital watermark embedment. As a result, an output signal of video having the digital watermarks embedded therein is produced. The digital watermarks are embedded into the target image with reference to another image located at a position earlier in time than the target image. Such digital watermark embedment suppresses a delay in output of an output image with reference to an input image.

Digital watermark-embedding apparatus, method thereof, and recording medium having recorded therein program for performing the method

Abstract: PROBLEM TO BE SOLVED: To provide a technology which makes a degradation in image quality compatible with compression resistance by adjusting embedment intensity. SOLUTION: An input image is divided into local regions, each of which is a macro block unit. Embedment intensity is determined for each of the local regions using calculated characteristic amount and a compression bit rate. The determined embedment intensity is used to insert digital watermarks into each of the local regions, and the input image is encoded, thereby outputting a compressed bit stream that has the digital watermarks embedded therein. Since a characteristics amount is calculated for each of small regions of the input image, the embedment intensity can be adjusted for each region and the degradation in image quality can be suppressed. A correspondence table corresponding to a predetermined compressed bit rate is used to adjust the embedment intensity, thereby determining the embedment intensity while taking into consideration the image quality of a digital watermark-inserted image subjected to image encoding. COPYRIGHT: (C)2004,JPO

Concrete pile and construction method of foundation structure by use thereof

Abstract: PROBLEM TO BE SOLVED: To provide a concrete pile having a great support force and a good workability, and its construction method SOLUTION: A plurality of widened nodes 2 are protruded with a vertical distance in a reverse triangular pyramid body 1 and vertical reinforcements embedded in concrete are extended out of the apex and jointed reinforcements 5 are projected to form a concrete pile (friction pile) A concrete pile A is embedded with compression into a position down to a level lower than the ground level a After embedment, the peripheral ground is cut to open to form a footing 13 The slab concrete 14 of a building is constructed on the footing 13 The concrete pile A, the footing 13, and a slab concrete 14 are integrated COPYRIGHT: (C)2004,JPO

Keyboard for keyboard instrument

Abstract: PROBLEM TO BE SOLVED: To provide a keyboard for a keyboard instrument which can be easily and surely mounted with weights into weight embedment holes and prevents the weights from rotating, shaking and dislodging. SOLUTION: The weight embedment holes 2 are formed at the prescribed points of the keyboard 1 and the weights 11 are fitted and fixed into the weight embedment holes 2. Each weight embedment hole 2 is formed to a through-hole consisting of a small-diameter hole portion 2A and large-diameter portions 2B and 2C disposed at the apertures at both ends of this small-diameter hole portion 2A. The weights 11 comprise two weight members 11A and 11B consisting of the flanged cylindrical bodies symmetrical to the center line, are respectively fitted into the weight embedment holes 2 from both sides of the keyboard 1 and are integrally coupled by coupling means 12, such as belleville screws and bolts. Metals, which are exclusive of lead and mercury and are large in specific gravity, and not harmful, for example, iron, brass, tungsten and sintered metals, or composite materials prepared by mixing at least any one of these metals and a synthetic resin at prescribed ratios are used for the weights 11. COPYRIGHT: (C)2003,JPO

Ductile embedment in brittle metal parts

Abstract: A cast pulverizer grinding ring made of cast brittle, white-cast iron has in creased resistance to failure by being provided with a mechanically intricate, light weight ductile material system embedded in the brittle metal. The surface of the embedded material i s coated, prior to casting, with a slurry of magnesium oxide particles in an alcohol vehicle to gether with a small amount of Bentonite particles (siliceous clay) and heat cured organic binder which resists attack by the molten metal and which avoids strong bonding with the solidified cast metal. The ductile embedment itself is a lightweight structure advantageously expanded metal. T he intimate contact between the ductile embedment and the cast metal provides structural support while the lack of a strong bond between the ductile embedment and the cast iron allows an elastic/plastic deformation of the ductile steel forming the embedment to differ from that o f the white-iron material cast therearound. The embedded ductile material holds the grinding ring together even if a through crack occurs.

Parameters affecting steel anchorages under shear

Abstract: Steel anchorages find various applications in concrete structures, including rehabilitation of deteriorated structures. Experiments were carried out to study the effect of various parameters on the load carrying capacity of steel anchors in shear, and the results compared with other published data and empirical formulae. It was found that there could be a large variation in the load capacities and the failure modes, depending on embedment length and the presence of reinforcement near the anchors. It was also found that the actual failure loads were sometimes considerably lower than the estimates given by available empirical relations. KEYWORDS: anchorages; structural anchors; fastening anchors; concrete; shear strength; capacity; design; repair; retrofitting

Uplift capacity of anchor plates in sand

Abstract: The theories and calculation formul as for the uplift capacity of anchor p lates in sand were reviewed and investigated .The effects of sand density,embedment ratio,plate geome tric properties and inclination were analyzed based on the current model tests and p revious research.The uplift capacity calculation methods of strip anch or were evaluated.With the introductions o f shape factor and inclination facto r,a general formula is proposed to calculate the uplift capacity of square anchor,which is most widely used in engineerin g.Finally,scale effects and the com parisons of general formula with the in-situ tests are discussed.

Manufacturing method for slope shoulder block for applying embedment to paddy field surface or upland field, and slope shoulder block manufactured by the method

Abstract: PROBLEM TO BE SOLVED: To provide a slope shoulder block product which is used for a sloped surface formed by a difference of elevation between a road and a paddy field or an upland field and which is formed in such a complicated shape as to give consideration to a finished surface, and a manufacturing method for the product, which makes a form cost low, which facilitates handling and which dispenses with a change in mixing of concrete even if the products are manufactured at a rate of two pieces per time and two rotations per day. SOLUTION: In terms of the shoulder block A and the manufacturing method therefor, a horizontal part 2 to be mounted on the road is constituted on an upper surface part; a horizontal-part product embedment part 1 of the product serves as a base part; the product is made symmetrical so that a part to be mounted on the road can serve as an upper concrete placing surface; a "truncated chevron-shaped" form enables the two pieces per time to be manufactured by means of an angle of inclination of the product in the construction of the sloped surface in such a manner that a nonslip pattern part is provided in a lower position; and a large opening 9-1 for allowing the passage of steam is constituted in both end frames of the form, so that the concrete can be placed. COPYRIGHT: (C)2005,JPO&NCIPI

Assesment of simplified pipe-soil interaction models

Abstract: .; . ; = = + = ) In pipeline design it is essential to predict lateral behavior of the pipe-soil interaction due to lateral loads resulting from relative movements or lateral buckling. Current design practice is to substitute the surrounding soil with a Winkler type foundation. The determination of the stiffness of the foundation is generally based on guidelines depending on general soil properties and embedment ratio.