scholarly journals EFFECTS OF ALTERNATELY CYCLIC VERTICAL LOADING ON BEARING CAPACITY AND PULL-OUT RESISTANCE OF A PILE WITH OR WITHOUT A WING PLATE

2012 ◽  
Vol 77 (681) ◽  
pp. 1683-1689 ◽  
Author(s):  
Kohji TOKIMATSU ◽  
Kei INAMURA ◽  
Hiroko SUZUKI ◽  
Masatoshi WADA ◽  
Hideyuki MANO
2017 ◽  
Vol 742 ◽  
pp. 636-643 ◽  
Author(s):  
Florentin Pottmeyer ◽  
Markus Muth ◽  
Kay André Weidenmann

An efficient implementation of lightweight design is the use of continuous carbon fiber reinforced plastics (CFRP) due to their outstanding specific mechanical properties. Embedded metal elements, so-called inserts, can be used to join metal-based attachments to structural CFRP parts in the context of multi-material design. They differ from other mechanical fasteners and have distinctive benefits. In particular, drilling of the components to be joined can be avoided and, depending on the preforming, fiber continuity can be maintained using such elements. Thus, no local bearing stress is anticipated. Previous work published by the authors [1] dealt with a systematic research of the influence of different types of stresses on the load bearing capacity of welded inserts. This contribution aims at the investigation of the performance of shape-optimized inserts under the same types of loading to compare with the results of the welded inserts serving as a reference. For that purpose, the respective load bearing capacities were evaluated after preinduced damages from impact tests and thermal cycling. In addition, dynamic high-speed tensile tests (pull-out) were conducted under different loading velocities. It is shown that the load bearing capacities increased up to 19% for high velocities (250 mm/s) in comparison to quasi-static loading conditions (1.5 mm/min) showing an obvious strain rate dependency of the CFRP. Quasi-static residual strength measurements under tensile loading identified the influence of the respective preinduced damages of the insert. Influence of the thermal loading condition was evaluated by placing the specimens in a climate chamber and exposing it to various numbers of temperature cycles from-40 °C to +80 °C with a duration time of 1.5 hours each. Here, it turned out that already 10 temperature cycles decreased the quasi-static load bearing capacity up to 31%. According to DIN EN 6038 the specimens were loaded with different impact energies and the residual strength were measured carrying out pull-out tests. It could be shown that the damage tolerance is significantly lower for the shape-optimized insert due to failure-critical delamination. The optimized insert also endured lower impact energies and the influence on the performance was higher.


2018 ◽  
Vol 174 ◽  
pp. 04012
Author(s):  
Jerzy K. Szlendak ◽  
Agnieszka Jablonska-Krysiewicz ◽  
Dariusz Tomaszewicz

The goal of the article is to elaboration analytical models describing a new system of reinforcing three-layer walls of large-panel buildings with bonded anchors. The use of this type of fasteners that bond the façade texture layer to the structural slab is necessary due to the low durability of previously used suspension elements. Various bonded anchorage systems were considered. The new anchorage systems were designed as two-anchors systems (horizontal anchor and diagonal anchors) and three-anchors systems (horizontal anchor and two diagonal anchors). The inclinations of these anchors are in the range of 30°-60° in relation to the surface of the element. For the above types of reinforcements, analytical models have been developed that take into account the change of strength parameters of the resin and steel from which the anchors were made, the interaction of materials resin-steel and resin-concrete and the effect of the simultaneous action of pull-out and shearing forces. Moreover, was assumed the simultaneous destruction of fasteners two- and three-anchors. The elaborated analytical models will be used to determine the load-bearing capacity of the new connector system, which will allow the elaboration of guidelines for strengthening three-layer walls of largepanel slab buildings.


2019 ◽  
Vol 23 (1) ◽  
pp. 118-131
Author(s):  
Jian Zhou ◽  
Xudong Zhi ◽  
Feng Fan ◽  
Anliang Jiao ◽  
Hongliang Qian

Precast shear wall structures have been widely used due to their outstanding features, and the joints between precast members play a critical role in complete structures, specifically for vertical joints. The ring joint is a new connection method used for the vertical connection. Few studies and related regulations were traced; therefore more detailed studies are required. In order to study the anchoring performance and failure behavior, an experimental model was designed and tested under monotonic axial loading, taking the composite height of ring rebars, concrete specifications, diameter of the horizontal rebars, relative position of the ring rebars, diameter of the ring rebars, and number of horizontal rebars into consideration. The failure phenomena were observed and the data were collected. The failure pattern, bearing capacity, yield ratio, displacement ductility coefficient, and other performance parameters were analyzed. The study indicated that the failure patterns are divided into ring rebar pull-out and ring rebar fracture. Increasing the composite height of the ring rebar, the concrete specifications and the number of horizontal rebars could improve the bearing performance, and the contribution of the horizontal rebar diameter was limited, and interlocking ring rebars arranged uniformly are not optimal. In the case of joint failure, the yield ratio is relatively small and the displacement ductility coefficient is larger, which shows the bearing capacity reserve is better. A numerical model was established to analyze the internal behavior, and the results were in good agreement with the experimental results, important for us to understand the failure behavior. Design recommendations will promote its application.


2010 ◽  
Vol 28 (3) ◽  
pp. 268-280 ◽  
Author(s):  
Teruo Nakai ◽  
Hossain M. Shahin ◽  
Feng Zhang ◽  
Masaya Hinokio ◽  
Mamoru Kikumoto ◽  
...  
Keyword(s):  
Pull Out ◽  

1986 ◽  
Vol 23 (4) ◽  
pp. 435-440 ◽  
Author(s):  
Vito A. Guido ◽  
Dong K. Chang ◽  
Michael A. Sweeney

Presented herein is a comparison of the results of laboratory model tests used to study the bearing capacity of geogrid and geotextile reinforced earth slabs. The parameters studied were the coefficient of friction between the geotextile and the soil, pull-out resistance between the geogrid and the soil, depth below the footing of the first layer of reinforcement, vertical spacing of the layers, number of layers, width size of a square sheet of reinforcement, and tensile strength of the reinforcement. For both geogrids and geotextiles, after an optimum number of layers or width of reinforcement, the bearing capacity did not increase. In addition, the bearing capacity was largest for those geogrid and geotextile reinforced earth slabs where the first layer was closest to the footing and the spacing between the layers was the smallest. Bearing capacity increased directly with increasing reinforcement tensile strength for the geotextile; however, for the geogrid, aperture size and reinforcement tensile strength must be looked at simultaneously. Key words: reinforced earth slab, geogrid, geotextile, bearing capacity, pull-out, friction.


2021 ◽  
pp. 204141962110592
Author(s):  
Kai Fischer ◽  
Jan Dirk van der Woerd ◽  
Wilfried Harwick ◽  
Alexander Stolz

Blast loading scenarios and the corresponding hazards have to be evaluated for infrastructure elements and buildings especially at industrial sites for safety and security issues. Point fixed corrugated metal sheets are often applied as façade elements and can become a hazard for humans if they are pulled off. This paper investigates the dynamic bearing capacity of such structural members in terms of their general bending behavior in the middle of the span and pull-out behaviors at the fixing points. The elements are fixed at two sides and the load transfer is uniaxial. An experimental series with static and dynamic tests forms the basis to identify the predominant failure modes and to quantify the maximum stress values that can be absorbed until the investigated structural members fail. The experimental findings are applied to create and to optimize an engineering model for the fast and effective assessment of the structural response. The aim is the derivation of a validated model which is capable to predict the blast loading behavior of metal sheets including arbitrary dimensions, material properties, and screw connections. Results of this study can be integrated into a systematic risk and resilience management process to assess expected damage effects and the evaluation of robustness.


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