•Applying the high-strength rings greatly improves ultimate load and initial stiffness.•The initiation of the concrete crushing is postponed after applying the high-strength rings.•The compressive ...stress in normal strength concrete is reduced after incorporating the high-strength rings.•Beam on inelastic foundation (BIF) theory can model the deterioration of concrete support stiffness.•The analytical solution is derived to predict the ultimate load of the high-strength ring strengthened dowel connection.
Traditional dowel connections embedded into concrete are susceptible to localised concrete crushing under heavy wheel loads. To address this issue, this paper introduces an innovative high-strength ring strengthened dowel connection to improve the bearing resistance of concrete at the joint surface. Monotonic load tests were conducted to investigate the effects of the high-strength ring concrete compressive strength, the high-strength ring thickness and length on improving ultimate load and mitigating localised concrete crushing. Test results indicated that the ultimate load and the initial stiffness of the specimen were greatly improved after applying the high-strength rings. Because of the excellent compressive resistance of the ring concrete, the initiation of the crushing zone was delayed, and the maximum compressive stress in normal strength concrete was reduced with the increase of the ring thickness. In addition, the deflection response of the dowel connection embedded into concrete could be predicted by the beam on elastic foundation (BEF) and the beam on inelastic foundation (BIF) theories. Based on the deformation of the dowel connection and surrounding concrete, the analytical solution was derived to predict the ultimate load of the high-strength ring strengthened dowel connection embedded into concrete.
The dowel-bearing tests were conducted to investigate the embedding strength of laminated bamboo parallel to grain for the design of dowel-type connections according to ASTM D 5764-97a. The embedding ...strength is evaluated by the 5% diameter off-set method and the maximum embedding strength is determined by the ultimate load. The effects of the specimen size, the loaded length and the bamboo strip arrangements on the test results have been discussed. The embedding strength decreases gradually with the increase of the thickness and the loaded length. The difference in embedding strength for different bamboo strip arrangements is negligible. The two typical failure modes and corresponding load-displacement curves have been analyzed. The theoretical results of embedding strength in different national standards have been compared with each other, and the calculation equation among dowel diameter and compressive strength parallel to grain is proposed by regression analysis of the test data. It presents a better prediction for the embedding strength of laminated bamboo.
•A FEM model of a beam-to-column dowel connection is defined.•The FEM model is validated on the results of an experimental monotonic shear test.•Parametric studies are performed in order to ...investigate the system behavior.•The dowel connection strength as well as the failure mechanisms are discussed.•The reliability of some common literature and code formulae is assessed.
One of the most common and serious damages due to an earthquake in precast buildings is the failure of the beam-to-column connection. This work investigates the shear behavior of RC beam-to-column dowel connections. A FEM model of the connection, detailed at the material level, is provided; it is validated by experimental evidences. Several parametric analyses are performed in order to investigate the influence of different variables on the connection behavior and the reliability of some literature formulae for the prediction of the dowel connection strength.
Precast reinforced concrete (PCRC) applications provide several structural, economic, and environmental benefits. Therefore, recently the PCRC elements have been widely used in construction ...implementation. However, the connection's behavior and its possible failure under different types of loads are considered essential challenges during the design of the PCRC elements. This study aimed to investigate the performance of the adhesive dowels connections and their shear capacity. The experimental phases focused on examining eighteen push-off concrete specimens and four reinforced concrete (RC) beams-column connections. While the numerical phase was conducted using the finite-element software package ANSYS to simulate concrete connections behavior. Push-off specimens consisted of two concrete blocks measured 250 mm in width. Blocks connected by steel dowel that crossed the shear plane. While beams measured 120 mm in width, 300 mm in depth, and 1400 mm in length. Beams connected to existing 300 mm square column with adhesive dowels. All specimens were loaded monotonically until failure through a constant loading rate. The experimental study aimed to evaluate the effects of the shear plane depth, dowels’ embedded length, dowels’ diameter, the edge distance, and dowels ratio The test results revealed that the shear plane conditions and area, as well as the adhesive dowels configurations, had a significant effect on the shear capacity of dowel specimen. Moreover, the finite element model provided a better understanding of the different modes of failure observed during experimental testing and the shear capacity of adhesive dowels.
In the present work, single- and double-dowel joints following different geometric configurations are experimentally and numerically investigated to derive the splitting behaviour of beech wood ...(Fagus sylvatica L.), one of the most widespread hardwood species in Europe for structural purposes. The influence of the spacing between dowels, their distance to the supports, and the slenderness of the beams is analysed. The correlation of the experimental failure loads with those predicted numerically by cohesive zone finite element-based models using the fracture properties of the species is discussed. The experimental results are also compared with those obtained from the normative expression included in Eurocode 5 and two other design models reported in the literature. The splitting failure loads predicted by both the analytical and numerical models were found to be conservative, the latter being closer to the experimental values.
As widely known, connections performance under seismic loads can significantly affect the structural response of RC precast buildings. Within the scientific community, an increasing number of studies ...has been carried out on this topic, in the light of the recent earthquake aftermaths all over Europe. Indeed, connections turned out to be the weakest part of the precast structures and their failure often provoked the global collapse of the whole building. The present study aims at assessing the seismic behavior of a single-story RC precast building in terms of global collapse implementing two different models of the beam-to-column connection, a simplified and a refined one. A lumped plasticity approach is used to simulate the structural nonlinear behavior at the column base. In order to assess the refined connection model, a preliminary scheme with an isolated single dowel is validated by comparing the pushover outcomes with experimental results from literature. Nonlinear static and dynamic analyses are performed on two models of a 3D single-story RC precast building, one implementing the simple beam-to-column connection model and the other one implementing the refined mode. The comparison clearly shows that the differences are negligible if the global collapse limit state is considered.
Capacity design, according to the modern seismic building codes, requires the application of specific rules and construction details in order to prevent brittle failure modes at material, element and ...structural level. In particular, with reference to single-story precast reinforced concrete structures with columns joined by pinned beams, the Italian seismic building code, following the Eurocode 8 general principles, requires that beam-to-column connection should be designed in order to avoid the connection failure before the formation of the plastic hinge at the column base. However, no specific details are provided in order to reach such a performance. Recent European earthquakes showed that seismic performance of beam-to-column dowel connections can be very poor. Hence, for European typical dowel beam-to-column connections, this study aims to investigate: (a) possible connection configurations obtained according to seismic design; (b) possible failure modes involving connection elements (steel dowel, transversal steel reinforcement, dowel concrete cover); (c) how available formulations are able to describe such failure modes and the related shear strength; (d) influence of connection failure on the global seismic safety at collapse of new designed single-story RC precast buildings. The reference buildings and beam-to-column connections are designed considering different geometrical layouts of the primary structure and different seismic hazard levels, i.e. four sites and two soil types. Structural capacity is estimated considering global, i.e. related to column plastic hinge degradation measured in terms of top lateral displacements, and local, i.e. related to connection shear strength, failure modes. Nonlinear multi-stripe analyses are performed for the seismic assessment.
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