Embedment

About: Embedment is a research topic. Over the lifetime, 2441 publications have been published within this topic receiving 31444 citations.

Bond between Glass Fiber Reinforced Plastic Reinforcing Bars and Concrete - Experimental Analysis

Abstract: Results of an experimental investigation on bond between a glass fiber reinforced plastic (GFRP) rebar and concrete are presented and discussed. Rebars used in tests are the FRP C-Bar(TM) produced by Marhall Industries Composites, Inc. Bond tests were carried out by using a test machine obtained from a modification of the standard scheme of the beam-test and were conducted on prismatic concrete specimens within which a #4 Grade B E-Glass C-Bar was embedded: the embedment length was ranging from 5 to 30 times the bar diameter, thus obtaining different test arrangements. Bond-slip relationships were obtained and bond mechanisms discussed. Furthermore, values of elastic modulus and tensile strength of rebar were evaluated. Finally, a bond-slip constitutive law obtained by means of a system identification procedure is presented. Numerical simulations of bond tests have been performed by using such bond-slip relationship and the obtained bond-slip curves have been compared with the experimental ones.

Experimental and Numerical Investigations of the Role of Proppant Embedment on Fracture Conductivity in Narrow Fractures (includes associated Errata)

Abstract: With the advancement of drilling and completion technologies in unconventional reservoirs, more extended reach wells are developed, and narrow-fracture environments are created in these reservoirs. Proppant embedment in monolayer/thin-layer-propped fractures can be significantly different from multilayer-propped fractures. In this study, a comprehensive investigation combining laboratory experiments with numerical simulations was conducted to explore the factors affecting proppant embedment and induced fracture conductivity loss in narrow fractures. The fracture-conductivity experiments were performed using monolayers of sand and ceramic proppant particles sandwiched between Berea Sandstone and Eagle Ford Shale plates under different closure pressures. The experiment study demonstrated that the long-term rock/fluid interaction leads to significant proppant embedment, and the fracture having a rough rock surface has higher fracture conductivity in monolayer-propped fractures. To further quantify the influence of proppant layer number, size, distribution variations, and particle crushing on proppant embedment, a numerical modeling approach that coupled continuum mechanics, discrete element method (DEM), and the lattice Boltzmann (LB) method was developed. In the simulation, the fracture/proppant system was constructed by filling proppant, modeled by DEM, between two fracture surfaces that were modeled by FLAC3D (Itasca Consulting Group 2012); LB simulation was then performed on the changing proppant pack to compute its time-dependent permeability. The numerical model was validated by comparing numerical results with measured fracture conductivities in the laboratory experiment. The simulation results demonstrated a strong correlation between proppant embedment and rock mechanical properties. When the Young’s modulus of the rock plate is less than 5 GPa, large magnitudes of proppant embedment can be expected in fractures supported by monolayers of ceramic proppant particles. Moreover, large-size proppant particles are more sensitive to the variations of Young’s modulus of the rock plate. When the rock formation in a narrow fracture environment has a relatively high Young’s modulus, the proppant diameter distribution has a lesser effect on the fracture conductivity. The outcome of this study will provide insights into the role of reservoir rock characteristics, proppant properties, and closure pressure on proppant embedment in narrow fractures.

Seismic Response of Hemispherical Foundation

Abstract: A time domain finite element method has been used to investigate the response to seismic waves of rigid, three-dimensional, embedded foundations The method eliminates the influence of artificial grid boundaries by completing the transient solution prior to the arrival of any nonphysical reflections The accuracy of the numerical procedure has been examined by comparison with analytic solutions; discrepancy is less than 5% at all frequencies up to β/a in which β=the shear wave speed of the embedment medium; and a is the foundation radius For a hemispherical foundation, the scattering of vertically incident S waves reduces the higher frequency horizontal translation of the foundation compared with the free-field motion but introduces a significant rocking component that is absent from the free field

Test of Headed Reinforcement in Pullout II: Deep Embedment

Abstract: A total of 32 pullout tests were performed for the multiple headed bars relatively deeply embedded in reinforced concrete column-like members. The objective was to determine the minimum embedment depth that was necessary to safely design exterior beam-column joints using headed bars. The variables for the experiment were embedment depth of headed bar, center-to-center distance between adjacent heads, and amount of supplementary reinforcement. Regular strength concrete and grade SD420 reinforcing steel were used. The results of the test the indicated that a headed bar embedment depth of was not sufficient to have relatively closely installed headed bars develop the pullout strength corresponding to the yield strength. All the experimental variables, influenced the pullout strength. The pullout strength increased with increasing embedment depth and head-to-head distance. It also increased with increasing amount of supplementary reinforcement. For a group of closely-spaced headed bars installed in a beam-column joint, it is recommended to use column ties at least 0.6% by volume, 1% or greater amount of column main bars, and an embedment depth of or greater simultaneously, to guarantee the pullout strength of individual headed bars over 125% of and ductile load-displacement behavior.