Embedment

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

Dynamic Response of a Sheet Pile of Fiber-Reinforced Polymer for Waterfront Barriers

Abstract: This paper presents the results from a combined experimental and advanced computational study to understand the dynamic response of a pultruded fiber-reinforced polymer (FRP) sheet pile of 9 m length that is installed into the ground near Venice, Italy The peak embedment force of 10 kN is applied at the top as a sinusoidal compression force having a maximum frequency of circa 760 Hz Physical measurements from accelerometers are reported for the lateral deformation response of a single sheet pile and of a unit restrained by an installed waterfront barrier A finite-element modeling methodology for the two test configurations is developed by using the Strand7 code, so that advanced computational results can be compared against the field application measurements Closed-form equations for the fundamental frequency are developed, with one accounting for the presence of rotary inertia and shear deformation Dynamic responses at different embedment lengths (1–7 m) are examined, and a very good correlation is found between theory and practice Numerically, the performance of the FRP sheet pile is compared with the response of a fictitious sheet pile of steel and with two new FRP geometries that increase stiffness to minimize flexure about the minor axis of bending By increasing the mass by 10%, the maximum lateral displacement can be the same as the steel unit and 1/20 of the tested FRP unit Findings of the research demonstrate that the FRP unit can be installed by using the same pile driving rig and procedure for steel sheet piling

The effect of fatigue cracks on fastener flexibility, load distribution, and fatigue crack growth

Abstract: : Fatigue cracks typically occur at stress risers such as geometry changes and holes. This type of failure has serious safety and economic repercussions affecting structures such as aircraft. The need to prevent catastrophic failure due to fatigue cracks and other discontinuities has led to durability and damage tolerant methodologies influencing the design of aircraft structures. Holes in a plate or sheet filled with a fastener are common fatigue critical locations in aircraft structure requiring damage tolerance analysis (DTA). Often, the fastener is transferring load which leads to a loading condition involving both far-field stresses such as tension and bending, and localized bearing at the hole. The difference between the bearing stress and the tensile field at the hole is known as load transfer. The ratio of load transfer as well as the magnitude of the stresses plays a significant part in how quickly a crack will progress to failure. Unfortunately, the determination of load transfer in a complex joint is far from trivial. Many methods exist in the open literature regarding the analysis of splices, doublers and attachment joints to determine individual fastener loads. These methods work well for static analyses but greater refinement is needed for crack growth analysis. The first fastener in a splice or joint is typically the most critical but different fastener flexibility equations will all give different results. The constraint of the fastener head and shop end, along with the type of fastener, affects the stiffness or flexibility of the fastener. This in turn will determine the load that the fastener will transfer within a given fastener pattern. However, current methods do not account for the change in flexibility at a fastener as the crack develops. It is put forth that a crack does indeed reduce the stiffness of a fastener by changing its constraint, thus lessening the load transfer.

Analysis of Steel Fiber-Reinforced Concrete Elements Subjected to Shear

Abstract: In this paper, a rational analysis procedure is presented for modeling the shear behavior of steel fiber-reinforced concrete (SFRC) elements. In the development of the analysis procedure, the Disturbed Stress Field Model (DSFM), based on the Modified Compression Field Theory (MCFT), is modified by implementing constitutive models for SFRC, which are derived from the Diverse Embedment Model (DEM). For the contribution of steel fibers, a local stiffness matrix for fibers has been developed separately from those for concrete matrix and conventional reinforcement. The composite element stiffness matrix for an SFRC element with conventional reinforcement is then derived by superposing the three local stiffness matrixes. In the element stiffness matrix, the effect of shear slip at a crack is also taken into account by considering the resistance due to steel fibers against shear stress on crack surface. Through comparisons with the test results of SFRC panels previously reported in the literature, it is shown that the actual shear behavior of SFRC panels are accurately predicted by the proposed analysis procedure, not only for the shear strength but also for the shear strain at the failure. Through implementation into finite element analysis programs, the analysis procedure devel oped in this paper can be useful in the modeling of SFRC members and structures also containing conventional reinforcement.

Analytical model for transfer length prediction of 13 mm prestressing strand

Abstract: An experimental investigation to determine the transfer length of a seven-wire prestressing strand in different concretes is presented in this paper. A testing technique based on the analysis of bond behaviour by means of measuring the force supported by the prestressing strand on a series of specimens with different embedment lengths has been used. An analytical bond model to calculate the transfer length from an inelastic bond stress distribution along the transfer length has been obtained. A relationship between the plastic bond stress for transfer length and the concrete compressive strength at the time of prestress transfer has been found. An equation to predict the average and both the lower bound and the upper bound values of transfer length is proposed. The experimental results have not only been compared with the theoretical prediction from proposed equations in the literature, but also with experimental results obtained by several researchers.

Braced Ductile Shear Panel: New Seismic-Resistant Framing System

Abstract: The conceptual design of an innovative seismic-resistant steel framing system capable of providing stiffness and ductility to new or existing structures is presented. The bracing system consists of concentric X-braces connected in series with rectangular sacrificial shear panels. The braces are designed to remain elastic during seismic events while the shear panels are sized and configured to dissipate ample energy through plastic deformation-induced stable hysteretic behavior. Detailed three-dimensional nonlinear finite-element analyses using ABAQUS are performed to characterize and quantify the effects of the design parameters on the local response of the bracing system and to adjust the design so that potential buckling of the elements is mitigated. The finite element predicted force-displacement curves of bracing systems that achieve the desired local behavior when subjected to a specified interstory drift are in turn translated into a SAP2000 nonlinear link element. Embedment of the link elem...