Embedment

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

Vertical vibration of a rigid circular disc embedded in a transversely isotropic and layered poroelastic half-space

Abstract: Fundamental solution for the time-harmonic vertical vibration of a rigid circular disc embedded in a transversely isotropic and layered poroelastic half-space is developed using a semi-analytical method. First, based on the Green's function of the time-harmonic vertical circular load embedded in the layered half-space, function of the corresponding annular ring load is determined via the method of superposition. Then the disc-medium contact area is discretized into annular ring elements with unknown densities which are determined via an integral least-square approach. Finally, the dynamic vertical compliance is derived by virtue of the equilibrium between the applied load on the disc and the resultant contact stress. Based on the derived fundamental solution, selected numerical examples on the dynamic vertical compliance are presented to investigate the influence of the surface hydraulic condition, fluid saturation, embedment depth of the disc, material anisotropy, material layering, and input frequency.

Vertical and torsional vibrations of an embedded rigid circular disc in a transversely isotropic multilayered half-space

Abstract: In this paper, we present a fundamental solution to the mixed boundary-value problem of vertical and torsional vibrations of a rigid circular disc embedded in a transversely isotropic multilayered half-space. We first introduce the cylindrical system of vector functions to express displacements and stresses of the layered half-space induced by the time-harmonic vertical and torsional loads acting within the half-space. We then derive the recursive relation of the expansion coefficients of the displacement and traction vectors from one layer to any other layer via the dual variable and position (DVP) method. Finally, by virtue of the boundary/interface and internal loading conditions, the expansion coefficients of the displacements and tractions are determined, which are integrated back to the physical domains. To satisfy the mixed boundary conditions at the embedded rigid-disc level, we divide the load disc area into many annular load-rings with the corresponding solutions being superposed together via an integral least-square approach. Based on the derived fundamental solutions, various numerical examples on the vertical and torsional dynamic compliances are presented to demonstrate the influence of the embedment depth of the disc, material layering, anisotropy, and input frequency. Furthermore, the derived fundamental solution is applied to a homogeneous half-space with a thin coating to investigate the suitability of two effective boundary conditions on the half-space.

Non-corrosive tie reinforcing and dowel bars for highway pavement slabs. final report

Abstract: The use of non-metallic load transfer and reinforcement devices for concrete highway pavements is a possible alternative to avoid corrosion problems related to the current practice of steel materials. Laboratory and field testing of highway pavement dowel bars, made of both steel and fiber composite materials, and fiber composite tie rods were carried out in this research investigation. Fatigue, static, and dynamic testing was performed on full-scale concrete pavement slabs which were supported by a simulated subgrade and which included a single transverse joint. The bahavior of the full-scale specimens with both steel and fiber composite dowels placed in the test joints was monitored during several million load cycles which simulated truck traffic at a transverse joint. Static bond tests were conducted on fiber composite tie rods to determine the required embedment length. These tests took the form of bending tests which included curvature and shear in the embedment zone and pullout tests which subjected the test specimen to axial tension only. Fiber composite dowel bars were placed at two transverse joints during construction of a new concrete highway pavement in order to evaluate their performance under actual field conditions. Fiber composite tie rods were also placed in the longitudinal joint between the two fiber composite doweled transverse joints.

Bond Performance of FRP Rebars With Various Surface Deformations in Reinforced Concrete

Abstract: One of the methods used to overcome the corrosion problem associated with steel rebars in reinforced concrete is the application of reinforced polymer (FRP) rebars. Bonding between the rebar and concrete is one of the major factors affecting the mechanical behavior of the structures. In this study, FRP rebars with four different surface configurations and geometries were constructed and their bonding to concrete was examined. These include a pultruded rod with a smooth surface (RO), externally wound FRP rib on the pultruded rod (RT), pultruded rod with sand sprayed on the surface (RS), and a combination of the last two configurations (RTS). Bonding strength of the rebars to concrete was assessed using pull-out test at the embedment lengths of 12 and 18 cm. Results showed that the increase in surface roughness of the rebars and hence a greater inter-mechanical locking, plays a major role in their bonding strength to concrete. RO rebar showed the lowest bonding strength to the concrete followed by the RT rebar. Bonding strength to concrete in the latter type was entirely controlled by the adhesion strength of the externally wound FRP rib to the pultruded core. RTS rebars with embedment length of 12 cm showed greater adhesion to the concrete, where as, in samples with embedment length of 18 cm, RTS and RS rebars showed close results. In all the tests conducted, delaminating of the surface texture was the major failure mode. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers