Analytical and numerical modeling of pullout capacity and interaction between hexagonal wire mesh and silty sand backfill under an in-soil pullout test

2003 ◽  
Vol 40 (5) ◽  
pp. 886-899 ◽  
Author(s):  
Chairat Teerawattanasuk ◽  
Dennes T Bergado ◽  
Warat Kongkitkul

During the pullout test, the pullout clamping system was modified and installed inside the pullout box with confinement from the fill material, hereinafter called the in-soil pullout test, which significantly reduced the necking phenomenon and the displacements mobilized during the pullout test. Subsequently, an analytical model was developed to predict the in-soil pullout resistance. In addition, a numerical modeling analysis, under the three-dimensional stress field conditions using the FLAC3D (fast Lagrangian analysis continua) program, was carried out to simulate the behavior of in-soil pullout tests. The laboratory in-soil pullout test results were then compared with the corresponding data obtained from the analytical and numerical modeling methods. The in-soil pullout resistance was greater than the corresponding result from previous pullout tests wherein the clamping system was conventionally installed outside the pullout box. The predicted pullout resistance results from FLAC3D agreed reasonably with the results from laboratory tests and with the results from the analytical modeling. The interaction coefficients, R, applied in the finite difference modeling of in-soil pullout tests were 0.90 and 0.65 for zinc-coated and polyvinyl chloride (PVC) coated hexagonal wire meshes, respectively. The predicted and measured pullout resistance of zinc-coated hexagonal wire mesh is approximately 20% greater than that of PVC-coated hexagonal wire mesh at the same applied normal pressure, because of the higher stiffness, EA, and higher shear stiffness, ks, of the zinc-coated mesh.Key words: hexagonal wire mesh, in-soil pullout test, pullout resistance, analytical modeling, numerical modeling.

2001 ◽  
Vol 38 (4) ◽  
pp. 782-795 ◽  
Author(s):  
D T Bergado ◽  
P Voottipruex ◽  
A Srikongsri ◽  
C Teerawattanasuk

The interaction behavior between hexagonal wire mesh and silty sand backfill can be evaluated from pullout tests. The pullout resistance of the hexagonal wire mesh reinforcement consists of two components, namely friction resistance and passive bearing resistance. The friction resistance – relative displacement relationship of a hexagonal wire mesh can be simulated by a linear elastic – perfectly plastic model. The passive bearing resistance of an individual bearing member can be modelled by a hyperbolic function. The friction resistances for galvanized and PVC-coated hexagonal wire mesh were 25 and 21%, respectively, of the total pullout resistance. A new analytical model for predicting the pullout resistance of hexagonal wire mesh reinforcement has been proposed. The proposed solution can estimate the maximum pullout force at different reinforcement levels from observed horizontal movement of a hexagonal wire mesh reinforcement.Key words: hexagonal wire mesh, necking phenomena, bearing resistance, analytical model, pullout box, bearing resistance.


Geogrid reinforcement of soil has been successfully used for many years in a wide variety of applications. This paper presents data obtained from a series of laboratory tests performed on the geogrid. The tests were conducted to determine the mechanical property including the tensile strength of the geogrid and its corresponding pullout test. Tests were performed to find out the effect of width of geogrid on the pullout resistance. It was found that the pull-out resistance of geogrid is a function of the relative density of the soil, the length and the width of geogrid specimen. A mechanism of soil-geogrid interaction is described and used to explain the results of' the pull-out tests. A significant finding is that the selection of geogrid specimen dimensions for laboratory pullout tests must take into account the strain to failure of the soil and the stiffness of the geogrid in order to properly represent the maximum pull-out stress that will be available in field applications.


2011 ◽  
Vol 374-377 ◽  
pp. 2520-2524 ◽  
Author(s):  
Gang Shi ◽  
Jian Xing Zhang ◽  
Yuan Qing Wang ◽  
Hui Juan Huang ◽  
Zheng Hong Zhang

In this paper, the experimental study on the self-tapping screw’s pullout resistance in the wood structure was conducted. Domestic ordinary screws were used together with imported or domestic wood to fabricate 6 screw connection specimens in wooden walls. Then monotonic loading tests were conducted and it can be concluded that, the common round screw connection strength mainly depends on the failure mode, the lack of cooperation effect significantly influences the strength of screw connections, and the dispersion of screw connection stiffness is high. So, to obtain formulae for the self-tapping screw connection strength and stiffness by further experimental study will be very necessary.


2013 ◽  
Vol 80 (4) ◽  
Author(s):  
Steven M. Kraft ◽  
Ali P. Gordon

Woven structures are steadily emerging as excellent reinforcing components in composite materials. Metallic woven meshes, unlike most woven fabrics, show high potential for strengthening via classical methods such as heat treatment. Development of strengthening processes for metallic woven materials, however, must account not only for behavior of the constituent wires, but also for the interactions between contacting wires. Yield behavior of a 325 × 2300 stainless steel 316L (SS316L) twill dutch woven wire mesh is analyzed via experimental data and 3D numerical modeling. The effects of short dwell-time heat treatment on the mechanical properties of this class of materials is investigated via uniaxial tensile tests in the main weave orientations. Scanning electron microscopy (SEM) is employed to investigate the effects of heat treatment on contacting wire interaction, prompted by observations of reduced ductility in the macrostructure of the mesh. Finally, the finite element method (FEM) is used to simulate the accumulation of plastic deformation in the mesostructure of the mesh, investigating how this wire level plasticity ultimately affects global material yielding.


2017 ◽  
Vol 2629 (1) ◽  
pp. 104-111 ◽  
Author(s):  
Agustin Spalvier ◽  
Kerry Hall ◽  
John S. Popovics

The use of nondestructive testing (NDT) techniques to estimate concrete in-place strength has been broadly studied, with proof of their usefulness in complementing destructive testing (DT). However, the use of DT techniques still dominates. The main objective of this investigation was to compare the performance of three NDT techniques—the rebound hammer, Nitto hammer, and pullout tests—to determine in-place strength. NDT-versus-strength correlation curves were fit to data measured from thick concrete slabs. Strength was measured from cast-in-place cylinders. Analyses of NDT sensitivity, uncertainty, and variability are presented. A new parameter to quantify the performance of the NDT techniques is proposed. This parameter is the limit error between the measured and estimated strengths, which combine uncertainty and variability analyses. The analysis shows that the least limit error for predicting in-place strength was achieved by the rebound hammer test when one testing location was considered or by the pullout test for two or more testing locations.


Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2278 ◽  
Author(s):  
Min Kyoung Kim ◽  
Dong Joo Kim ◽  
Young-Soo Chung ◽  
Eunsoo Choi

The feasibility of the crack closure of cementitious composites reinforced with shape memory alloy (SMA) fibers was investigated by performing single-fiber pullout tests. To demonstrate the fast crack closing ability, in this study, a heat treatment (300 °C) was applied for a short time (10 min). A short heat treatment was applied for 10 min, after the slip reached 0.5 mm, to activate the shape memory effects of cold-drawn SMA fibers. Two types of alloys were investigated, NiTi and NiTiNb, with two geometries, either smooth or dog-bone-shaped. During the heat treatment, the pullout stress of the SMA fibers initially decreased due to thermal extension, and then increased after heating for 1–3 min, resulting from the shape memory effects. However, their pullout stress recovery during and after the heat treatment was different for the different alloys and fiber geometries. The NiTi fibers generally produced a higher and faster recovery in terms of their pullout stress than the NiTiNb fibers, while the dog-bone-shaped fibers showed a faster pullout stress recovery than the smooth fibers.


2017 ◽  
Vol 54 (5) ◽  
pp. 621-630 ◽  
Author(s):  
S.H. Sadat Taghavi ◽  
M. Mosallanezhad

The pullout resistance of reinforcement, such as geogrids in mechanically stabilized earth (MSE) walls, includes the skin friction between the soil and solid geogrid surfaces. It also includes the bearing resistance against the transverse ribs, which has a greater influence on the production of pullout resistance. Taking the current limitations involved in producing woven polyester geogrids into consideration (i.e., the limited thickness of the transverse ribs), the amount of bearing resistance developed in front of transverse ribs is limited in the pullout mechanism. Thus, along with introducing an innovative and applied system, this research has endeavoured to demonstrate the effective performance of this new system in increasing the passive resistance — and thereby the pullout resistance — of standard geogrids. This new system, which is formed by adding steel transverse elements (a set of steel equal angles) to the ordinary polyester geogrids by means of nuts and bolts, is called an anchored geogrid (AG). The experimental results show that a spacing-to-height ratio of transversal elements equal to 5 gives the maximum pullout resistance for a polyester AG system in sandy soil used in the study. With an optimum arrangement, this system is capable of increasing the pullout resistance of the ordinary geogrid system by 65%. In addition, based on the plasticity solution, the pullout bearing failure mechanisms of a single isolated transverse element in the polyester AG system depend on overburden pressures.


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