Concrete Dowels Research Articles

Beam-in-Slab Low-Volume-Road Bridge System

Funding for the repair and replacement of structurally deficient and functionally obsolete bridges is a nationwide problem. This problem is magnified for the managers of low-volume-road (LVR) systems who have limited budgets; thus, innovative replacement alternatives are always being sought. The beam-in-slab bridge (BISB) is an alternative replacement bridge developed in Iowa. The bridge consists of W-beam sections spaced 24 in. (610 mm) on center, with concrete filling the void space between them. Spans up to 50 ft (15.24 m) can be constructed with this low-cost alternative. Field and laboratory testing confirmed that the system is capable of handling legal loads. Modifications to the BISB have been investigated to improve its structural efficiency to make it possible to use the system in longer spans. An alternative shear connector (ASC) has been developed to provide composite action in the BISB. The ASC consists of holes, either torched or drilled, through the web of the girder for the formation of concrete dowels that provide for composite action. Ongoing research promises more structural efficiency with the development of an arched formwork system, which will make possible wider girder spacings and reduced self-weight. Combining the ASC with the arched formwork should result in an essentially steel-free system that is relatively easy to construct. From initial results, it should be possible to construct spans up to 75 ft (22.86 m) to carry legal loads in Iowa with these modifications.

MEASURING THE DEFLECTED SHAPE OF A DOWEL BAR EMBEDDED IN CONCRETE

The instrumentation produced excellent data with regard to the small deflections of a dowel bar embedded in concrete. In this study, dowel load versus deflection characteristics were successfully measured for combinations of concrete strength, dowel diameter, and joint opening widths within the ranges of practical interest. The deflections of embedded dowels were found to be significantly affected by these variables for the ranges tested. As indicated by the experimental data, the prediction equation based on theory of a beam resting on an elastic foundation did not properly represent the dowel deflections due to the nonlinear nature of the physical system, even at relatively low levels of applied load. The instrumentation technique should have application for other problems where internal displacements of elements embedded in concrete are desired, such as dowel action in the shear of concrete beams.

Nonlinear finite-element analysis of concrete dowels

Numerical studies used to investigate the bearing and deformation behavior of a new shear connector called ‘concrete dowel’, are presented. In performing the nonlinear analyses, the ADINA finite-element computer code was used. The validity of the finite-element model is shown by comparison with results of experimental tests.

A parametric study of perfobond rib shear connectors

This paper summarizes the results of 40 push-out test specimens with a new type of shear connector called perfobond rib. This connector is a flat steel plate with a number of holes punched through. The test specimens were designed to study the effect of a number of parameters on the shear capacity of the connection. These were the number and spacing of rib holes, transverse reinforcement, and compressive strength of concrete. The main objective of this study was to derive an expression for predicting the capacity of perfobond rib connector based on the results of the parametric study.The test results indicate that the shear capacity of the perfobond rib connector increases with the number of rib holes as long as the hole spacing is at least 2.25 times the diameter of the holes. The effect of increasing the transverse reinforcement ratio from 0.27% to 0.36% was an increase of approximately 16% in the shear capacity of the connection. Similarly, an increase of 36% in the shear connection capacity was achieved due to a 63% increase in concrete strength.An expression for computing the shear capacity of perfobond rib connectors is proposed. A regression analysis, which is based on a model that takes into account the contributions of concrete dowels formed by the rib holes, the transverse reinforcement, and the strength of concrete, was used in the derivation. Key words: composite beam, perfobond rib connector, headed stud, push-out test, compressive strength of concrete, transverse reinforcement.

Landslide stabilization using drainage wells, concrete dowels and anchored bore pile walls : Wichter, L; Krauter, E; Meiniger, W Proc 5th International Symposium on Landslides, Lausanne, 10–15 July 1988V2, P1023–1028. Publ Rotterdam: A A Balkema, 1988

Landslide stabilization using drainage wells, concrete dowels and anchored bore pile walls : Wichter, L; Krauter, E; Meiniger, W Proc 5th International Symposium on Landslides, Lausanne, 10–15 July 1988V2, P1023–1028. Publ Rotterdam: A A Balkema, 1988

Paso elevado, en Manchester – Inglaterra

This is an urban main traffic connection, running south of the civic centre of Manchester, and facilitates communications in the East West directions. It also links the main motor roads entering the city from the South. It involves a viaduct with two traffic directions, with a total length of 975 m, which runs over several highways and pedestrian footpaths. The article describes the structure of this viaduct and its special features, such as an improved type of prestressed concrete dowels and certain construction problems.

Use of electricity to treat disease fulfills half-century-old prophecy

The paper deals with realized push test of composite element (RC flanges with GFRP panel web). Connection between RC flanges and GFRP web is fixed by concrete dowels and sand-blast of GFRP surface. The results obtained from push test are compared with numerical analysis (ATENA-3D) and theoretical models which was published in technical literature.