Dowel

Rigid concrete pavements subjected to several types of dynamic loading such as the vehicle movement loading that may result in joint cracking due to this type of loading. The objective of this study was to develop the modified Bolotin model of the rigid pavement to assess the vertical deflection, the flexural stress of the plate as well as the performance of dowel in rigid concrete pavement. The discontinuity between the plate is using dowels that restrain the rotation and the vertical deflection along the edges. The first and second type of Levy's problems is used to find eigenvectors of the pavement, while the eigenvalues are found from the transcendental equations in the x-and y-directions. Important factors that include the combined effects of loading velocity and the diameter of dowel are frequently ignored in most of the recent works. To overcome the inadequacies of the recent works, the present study investigated the rigid roadway pavement stress distribution under the effect of some model parameters. The results of the present study were verified by comparing with the other methods results from the recent study. Results showed that the stress distribution along the edges depends on the diameter of the dowel, the thickness of the rigid roadway pavement, and the soil conditions beneath it. In conclusion, to identify the effects of different features which include the geometry of the pavement, material properties the pavement and movement behavior of vehicles to the structural responses of rigid roadway pavement, the modified Bolotin method developed in the present study is suitable.

Threaded titanium bars, installed in drilled holes and connected to the marble by means of white cement mortar, have been used to date to connect pieces of fractured architectural members. In these applications, titanium bars are subjected to tension. With the aim to protect original members, the main criterion adopted for the design of the connections was to exclude failure of the connected marble pieces. The relevant design method [Zambas (1 88), Zambas (1 2)] is supported by experimental evidence.

Furniture must be designed to suit the intended use. Producers need to guarantee its quality and stiffness. During external loading, there are internal forces that can be transmitted and may result in a failure. This article examines the dowel joint, which is one of the most popular furniture joints. It discusses the effects of selected parameters, such as type of loading (tension and pressure), the size of the dowel (one-half or one-third of the joined parts), wood species [beech (Fagus sylvatica L.) and spruce (Picea abies L.)], and the adhesives type (polyvinyl acetate and polyurethane), on the joint stiffness. The effect of the annual rings was also monitored; however it was not determined as significant. Based on the results, the dowel joint is recommended with greater diameters and while using PVAc gluing. Article also deals with test simulation in virtual environment using the programme Solidworks.

The stress capacity of joints made of modified wood members under loading can be affected by design of joints and type of adhesive. Hence, these factors were addressed in this study by assessment of stress capacity variations in corner joints under diagonal applied compressive load induced combined stresses. The joints with mitered and butted design were constructed by application of epoxy and polyvinyl acetate (PVAc) adhesives from furfurylated wood samples with two weight percentage gains (WPGs), i.e., 20% as low level and 60% as high level. Results indicated that stress capacity in both corner joints was not significantly decreased with increasing polymerization of furfuryl alcohol (FA) in wood. Despite the high compression strength in mitered joint, the induced compression stresses were low in comparison with butted joint. The stress capacity in mitered joint bonded with epoxy adhesive enhanced with increasing the level of furfurylation. This was true for shear stress parallel to grain as well. Generally, it could be concluded that mitered joint made of furfurylated members and bonded with epoxy adhesive would be stronger than other corner joints.

ABSTRACT Historically, wooden peg connections have been widely used in timber joints, particularly during the Middle Ages, and the use of these wooden connections is becoming popular again. In this article, an experimental investigation of seven different combinations of pegged connection parameters is presented. Embedment, single-shear, and double-shear tests of pine peg connections were loaded parallel and perpendicular to the grain under monotonic static compressive loads. Pegs of 10, 15, and 20 mm diameters were tested in three different shapes: straight cylindrical, straight traditional, and conical traditional. All peg shapes exhibited similar maximum loads, but straight traditional pegs exhibited greater stiffness than cylindrical pegs due to the tight fit of the peg. The ultimate load capacities of the straight traditional and cylindrical peg connections were then compared to a model based on Johansen’s theory of timber connections and were accurately predicted in both single and double shear.

Joints in concrete pavements are built to allow slab volumetric variations avoiding random cracks. Moreover, as they are discontinuities, the use of dowel bars prevents loss of load transfer across joints. During bars installation or even concrete casting, misalignments and misallocations of those devices may occur, affecting the concrete pavement structural performance. This study explores the effects of such non-conformities in the positioning of dowel bars through numerical modeling, using the 3D finite element program EverFE2.25. For, numerical simulations, bending stresses in concrete slabs of a typical bus corridor were ascertained, varying misalignments types and magnitudes (vertical tilt and horizontal skew), base type (cemented and asphalt), slab/base interface bond conditions and concrete thermal differential. Results disclosed the contribution of using bonded base in reducing stresses, even when the dowels were severely misaligned while slabs were subjected to high therma...

The present study deals with the innovation and the possibilities of improving the design solution of a frame connection for two selected types of fasteners. All specimens were made of glued laminated timber. Dowel-type mechanical fasteners, a combination of bolts and dowels, and full-threaded screws were used for the connection. The main goal of this research was to replace the typical solution (common dowel-type fasteners) with a more modern, faster, and easier solution in order to improve the load-carrying capacity, ductility, and deformation capacity of this type of frame connection. This article also aimed to provide a detailed evaluation of the mechanical properties of the used glued laminated timber and fasteners in order to comprehensively evaluate the research task. For the design solution, a frame connection created from a system of two struts and a partition was chosen as the basis of the experimental program. Dowel-type mechanical fasteners, as well as combinations of bo...

Renovation, restoration, remodeling, refurbishment, and retrofitting of build-ings often imply modifying the behavior of the structural system. Modification sometimes includes applying forces (i.e., concentrated loads) to beams that before were subjected to distributed loads only. For a reinforced concrete structure, the new condition causes a beam to bear a concentrated load with the crack pattern that was produced by the distributed loads that acted in the past. If the concentrated load is applied at or near the beam’s midspan, the new shear demand reaches the maximum around the midspan. But around the midspan, the cracks are vertical or quasi-vertical, and no inclined bar is present. So, the actual shear capacity around the midspan not only is low, but also can be substantially lower than the new demand. In order to bring the beam capacity up to the demand, fiber-reinforced-polymer composites can be used. This paper presents a design method to increase the concentrated load-carry...

Corner joints are critical points of wooden structures not only in furniture construction but also in traditional wooden architecture, especially in constructions without nails. This study was performed to determine the effects of particular factors such as the axis of assembly, types of material, and adhesive on the tensile performance of various modern and traditional types of wooden corner joints. For this purpose, various corner joint specimens were prepared with three different wooden materials: Scots pine (Pinus sylvestris Lipsky) wood, Lombardy poplar (Populus nigra Lipsky) wood, and Medium Density Fibreboard (MDF) using two different adhesives: polyvinyl acetate (PVAc) and polyurethane (Desmodur-VTKA) glues; and five different wooden joint types: dowel, tongue-and-groove, half-blind dovetail, screw, and eccentric screw joints. Tensile performance tests, vertical and parallel to the axis of assembly, were carried out according to ASTM D 1037 guidelines. Experiments indicated ...