Showing papers on "Embedment published in 1995"

Bond of hooked glass fiber reinforced plastic (gfrp) reinforcing bars to concrete

Abstract: The objective of this study was to examine the bond behavior of hooked glass fiber reinforced plastic (GFRP) reinforcing bars to concrete. Thirty-six 90-deg hooked reinforcing bar specimens were tested to determine the effects of concrete compressive strength, radius of bend, tail length, straight embedment length, and reinforcing bar diameter under monotonic static loading. The slip between the reinforcing bars and concrete was measured at the loaded end for various load levels. The tensile load was applied to the reinforcing bar until splitting of concrete or fracture of reinforcing bar occurred. The test results revealed that, with increases in concrete compressive strength, radius of bend, and straight embedment length, the ultimate tensile stress and initial stiffness increased and the maximum slip at failure decreased. The tail length beyond 12 bar diameters had little effect on the ultimate tensile stress. Based on a regression analysis of the test results, investigators recommend that the development length of hooked GFRP bars be taken as 16 times the bar diameter.

Identification of Stress-Slip Law for Bar or Fiber Pullout by Size Effect Tests

Abstract: Test results on the size effect in the pullout strength of reinforcing bars embedded in concrete are presented. Attention is focused on failures due solely to interface slip, with no cracking in the surrounding concrete. This type of failure is achieved by using smooth round bars and a sufficiently large ratio of bar diameter to embedment length. Elimination of cracking in the surrounding concrete makes it possible to study the characteristics of the interfacial shear fracture between steel and concrete. The results of tests of geometrically similar specimens show that interfacial shear fracture causes a size effect on the nominal strength in pullout. The size effect is found to be transitional between plastic failure (the current approach of concrete design codes, for which there is no size effect) and linear elastic fracture mechanics (for which the size effect is the maximum possible). This transitional size effect can be approximately described by the size effect law proposed by Bažant in 1984 for qua...

Single shear joint

Abstract: A single shear joint is provided which includes a conical ferrule establishing a nesting means of engagement with controlled embedment between a link and a mating component.

Composites of fluoropolymers with thermally non-adherent non-fluoropolymers and methods for producing the same

Abstract: A composite of thermally non-adherent fluoropolymeric and non-fluoropolymeric components is created through the agency of a non-woven, fibrous binder interposed between and portionally embedded into both components. The fibers of the non-woven binder have a substantial portion of their length extending into both components and cross the interface at an angle that is substantially normal to the plane of embedment. The composite possesses good peel-adhesion behavior between the otherwise thermally non-adherent components.

Bond behaviour of deformed bars in NSC and HSC: Experimental study

Abstract: In order to derive a general bond stress - slip relationship for deformed bars in concrete, tests have been carried out on bond behaviour of bars in normal strength and high strength concrete, for various confining conditions. This report focuses on a first test series, which was carried out on bars with large embedment lengths, cast into massive concrete specimens. The experimental results of this test series are used to formulate bond stress - slip relation. Proposed model considers the effect of steel yielding and permits optimum utilisation of increased bond strength of high strength concrete. This is an important extension with respect to the bond model formulation given in the CEB-FIP Model Code.

Behavior of a shallow plate anchor in clay under sustained loading

Abstract: Laboratory model test results for the uplift of a shallow circular plate anchor embedded in a soft saturated clay are presented. For all tests the bottom of the anchor plate was vented to eliminate the mud suction force. The tests were divided into two categories: (1) short‐term tests to determine the variation of the net ultimate uplift capacity and hence the breakout factor with embedment ratio, and (2) creep tests with sustained uplift loads at varying embedment ratios. Based on the model test results, the variation with time, has been determined for the rate of strain of the soil located above the plate anchor. Empirical relationships for obtaining the rate of anchor uplift have been proposed.

Concrete structural body with embedment base

Abstract: PURPOSE:To improve efficiency in execution of work, and to prevent cracks from occurring to welded parts when legs of equipment are welded to an embedment base. CONSTITUTION:An embedment base 5 is set to a concrete footing area formed to a lot 3 by excavation. An elastic spacer 20 is stuck to the outer peripheral face of the embedment base 5, and concrete is placed to the inside of the concrete footing area, and a concrete structural body is constructed in the lot 3 after curing of the concrete. Then, legs of equipment are welded to the embedment base 5 and sealing material is applied so that the spacer can be embedded therein, and installation of the equipment is made.

Doubly-propped embedded retaining walls in clay

Abstract: A series of centrifuge tests and finite element analyses have been carried out to investigate the behaviour of multi-propped retaining walls of varying embedment depth, construction sequence and pre- excavation lateral stresses. The results are reasonably consistent and are discussed with reference to their design implications. (A)

Embedment type fixture

Abstract: PURPOSE:To improve corrosion-resistance and tensile strength of an embedment type fixture of a nut type which fixes a bolt for fixing equipment to a concrete structure or for lifting a concrete structure. CONSTITUTION:A nut 1 which is screwed with a bolt is covered with a cap 9. A cylindrical body 6 is integrated with the cap 9, both of which are made of resin, while the cylindrical body 6 securing embedding depth of the nut 1 and an insertion hole 8 of the bolt. It is thus possible to use the ordinary metal nut 1 without considering its corrosion.

Non-metallic type optical fiber cable for direct embedment

Abstract: PURPOSE:To provide a nonmetallic type optical fiber cable for direct embedment so improved as to satisfy required external pressure resistance and impact resistance without using a metallic material for mechanical protection CONSTITUTION:This optical fiber cable is constituted by successively applying an internal plastic sheath 2', a water absorptive tape layer 6 and an external plastic sheath 4 on the outer periphery of an optical fiber cable core 1 This internal plastic sheath 2' has many projecting parts 21 which project in parallel while having gaps 7 in the circumferential direction of the outside surface thereof and are continuous along the longitudinal direction of the cable The projecting ends of the respective projecting parts are formed tiltable and formed in contact with the inside surface of a water absorptive tape layer 6 The external pressure or impact received on the external plastic sheath 4 is absorbed and relieved by the change of the tilting state by as much as the gaps 7 of such projecting parts 21 In addition, the moisture infiltrating the spacings between the internal and external plastic sheaths 2' and 4 is absorbed by the water absorptive tape layer 6 to prevent running water

Calculation of the temperature of permafrost cooled by small-diameter heat siphons

Abstract: An effective method is proposed for calculation of the temperature fields beneath structures built on fills cooled by a system of small-diameter (as compared with the depth of embedment) horizontal vapor-liquid heat siphons. A comparison is made with results of computer-assisted mathematical modeling by the finite-difference method.

Positioning method for insert or the like, and positioning sheet therefor

Abstract: PURPOSE:To make positioning possible for embedment of insert or the like without the need for individual measurement for positions, and to improve efficiency in positioning work while saving man power. CONSTITUTION:A first positioning sheet 7 and a second positioning sheet 8 in sizes respectively corresponding to a first reference plane pattern for use in common to rooms A1-A22 and a second reference plane pattern for use in common to rooms B1-B4 are prepared, and positioning holes 7a and 8a corresponding to positions for embedment of inserts or the like are formed respectively to the sheets 7 and 8. Then, the sheets 7 and 8 are laid on a form 1 or a deck plate 3 so that the sheets can agree with parts in each of the rooms, and positions for embedment of inserts or the like are marked to the form 1 or the deck plate 3, utilizing the positioning holes 7a and 8a. Such work is executed repetitiously on parts in rooms in the same pattern.

Free vibrations of rigid massive rectangular foundations embedded in a viscoelastic half-space

Abstract: A method is presented to analyse the free vibration of a rigid massive rectangular foundation buried to some extent beneath the surface of the ground. The response is evaluated using the complex eigenvalue analysis which is mathematically accurate and employs complex, nonclassical vibration modes. Taking the frequency dependence of dynamic impedance functions for the embedded foundation into account, the dimension less damped natural frequency for each mode is obtained as a single real root of transcendental real frequency equation. The numerical results including the dynamic interaction effects are compared with those obtained at neglected radiation damping in the supporting medium and based on static data. It is shown that the embedment of the foundation and the state of backfill considerably affect its complex eigenvalues.

A study on passive earth pressure acting on the embedment of an earth retaining wall for braced excavation work in cohesive soil

Abstract: 掘削土留め工の応力と変形に大きな影響を与える受働土圧の計算には, 古典的な極限土圧であるランキン・レザールの式, あるいはクーロンの式を, それぞれ粘性土地盤と砂質土地盤に使用しているのが現状である. これらの古典的な受働土圧の計算式は, 掘削工事での掘削幅の影響などを適切に考慮することはできない. この論文では二次元状態の粘性土地盤に限定して, 掘削幅や土留め壁表面のせん断抵抗を考慮し得る受働土圧の計算式を誘導し, その計算式に含まれる係数を弾塑性有限要素法の計算結果を用いて決定する. また得られた受働土圧の計算式の適用性を見るために模型実験との比較を行う. 結果として実用に供し得る受働土圧の計算式を提案する.