Investigation of the load-bearing behavior of composite joints in cross-section supplements for concrete structures

2021 ◽  
Author(s):  
Christian Knorrek ◽  
Sven Bosbach ◽  
Josef Hegger
Keyword(s):  
Bearing Capacity ◽  
Structural Concrete ◽  
Load Bearing Capacity ◽  
Research Project ◽  
Cross Sectional ◽  
Ongoing Research ◽  
Load Bearing ◽  
Existing Structures ◽  
Composite Joint ◽  
Bearing Behavior

<p>The strengthening with cross-sectional supplements made of reinforced concrete is already of great importance in building, bridge, and industrial constructions and will be further developed in the future because of the increasing demands on existing structures [1]- [3].</p><p>As part of an ongoing research project at the Institute of Structural Concrete at RWTH Aachen University, funded by the German Federation of Industrial Research Associations (AiF), a correlation between the method of surface treatment of the old concrete, the measured roughness, the type of concrete supplementation, and the load-bearing capacity of the composite joint has to be derived by means of new systematic test series. As a result, a database, and a possible practical guide on the load-bearing capacity of different combinations of old concretes, surface treatments, supplementary concrete layers, and bonding conditions will be developed. This paper will present the initial findings from this research project.</p>

Load-Bearing Capacity of Direct Inlay-Retained Fibre-reinforced Composite Fixed Partial Dentures with Different Cross-Sectional Pontic Design

2017 ◽  
Vol 68 (1) ◽  
pp. 94-100
Author(s):  
Oana Tanculescu ◽  
Adrian Doloca ◽  
Raluca Maria Vieriu ◽  
Florentina Mocanu ◽  
Gabriela Ifteni ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Fracture Pattern ◽  
Load Bearing Capacity ◽  
Cross Sectional ◽  
Load Bearing ◽  
Reinforced Composite ◽  
Polyethylene Fibre

The load-bearing capacity and fracture pattern of direct inlay-retained FRC FDPs with two different cross-sectional designs of the ponticwere tested. The aim of the study was to evaluate a new fibre disposition. Two types of composites, Filtek Bulk Fill Posterior Restorative and Filtek Z250 (3M/ESPE, St. Paul, MN, USA), and one braided polyethylene fibre, Construct (Kerr, USA) were used. The results of the study suggested that the new tested disposition of the fibres prevented in some extend the delamination of the composite on buccal and facial sides of the pontic and increased the load-bearing capacity of the bridges.

scholarly journals Fatigue and crack propagation investigations on composite dowels using an inclined single push-out test

2018 ◽  
Author(s):  
Kevin Wolters ◽  
Markus Feldmann
Keyword(s):  
Crack Propagation ◽  
Bearing Capacity ◽  
Fatigue Behaviour ◽  
Steel Part ◽  
Stress Distributions ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Composite Joint ◽  
Residual Capacity ◽  
Push Out

The current fatigue design of composite dowels is based on the structure stress concept for the steel part and upper load limitations to avoid concrete fatigue and a degradation of the composite joint. Therefore the aim of the existing concept is to avoid any fatigue of the composite structure. A fatigue concept considering residual load bearing capacity of torn steel connectors and the transfer of forces to less stressed composite dowels in the beam has great economic potential and leads to a better safety assessment. Therefore, further investigations of fatigue behaviour and crack propagation of composite dowels are necessary. In a first step a single composite dowel is investigated in small-part tests. By the use of finite element models a new inclined single push-out test stand has been developed in order to reproduce the force and stress distributions within a composite beam as precisely as possible with the small-part tests. This ensures the comparability of the crack initiation location and crack propagation. In the test series the influences of different stress ranges and cycle numbers on crack propagation of the steel dowel are investigated. Furthermore the residual load-bearing capacity is determined and compared to static load-bearing behaviour of uncracked steel parts of composite dowels. This paper concentrates on the numerical evaluation of crack propagation and residual capacity.

Assessment of Load-Bearing Capacity of Bridges

2017 ◽  
Vol 259 ◽  
pp. 113-118 ◽  
Author(s):  
Jaroslav Navrátil ◽  
Michal Drahorád ◽  
Petr Ševčík
Keyword(s):  
Bearing Capacity ◽  
Prestressed Concrete ◽  
Iterative Solution ◽  
Concrete Bridges ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Prestressed Concrete Bridges ◽  
Existing Structures ◽  
Non Linear

The paper aims to the determination of load-bearing capacity of reinforced/prestressed concrete bridges subjected to the combination of all components of internal forces according to Eurocode standards for assessment of existing structures. Undoubtedly bridge load rating is laborious hand-iterative process, especially when it comes to reinforced and/or prestressed concrete bridges. The engineer can spend days and weeks trials and errors in the estimation of bridge load-carrying capacity. The problem lies in the determination of load-bearing capacity of cross-section subjected to the combination of normal and shear forces, bending and torsional moments. Due to the different effects of permanent and variable loads and the non-linear behavior of structural materials, the problem becomes non-linear and its solution requires the use of suitable iterative method. Optimized iterative solution was implemented into IDEA StatiCa software and the results are presented in this paper.

Experimental and numerical investigation on the vertical bearing behavior of discrete connected new-type precast reinforced concrete floor system

2020 ◽  
Vol 23 (11) ◽  
pp. 2276-2291
Author(s):  
Rui Pang ◽  
Yibo Zhang ◽  
Longji Dang ◽  
Lanbo Zhang ◽  
Shuting Liang
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cover Plate ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Concrete Floor ◽  
New Type ◽  
Vertical Bearing ◽  
Floor System ◽  
Bearing Behavior

This article proposes a new type of discrete connected precast reinforced concrete diaphragm floor system that consists of precast flat slabs and slab joint connectors. An experimental investigation of discrete connected new-type precast reinforced concrete diaphragm under a vertical distributed static load was conducted, and the effect of slab joint connectors on the load-bearing capacity was evaluated. Then, a finite element analysis of discrete connected new-type precast reinforced concrete diaphragm, precast reinforced concrete floors without slab connectors, and cast-in-situ reinforced concrete floor were performed to understand their working mechanism and determine the differences in load-bearing behavior. The results indicate that the load-bearing capacity and stiffness of discrete connected new-type precast reinforced concrete diaphragm increase considerably as the hairpin and cover plate hybrid slab joint connectors can efficiently connect adjacent precast slabs and enable them to work together under a vertical load by transmitting the shear and moment forces in the orthogonal slab laying direction. The deflection of discrete connected new-type precast reinforced concrete diaphragm in orthogonal slab laying direction is mainly caused by the opening deformation of the slab joint and the rotational deformation of the precast slabs. This flexural deformation feature can provide reference for establishing the bending stiffness analytical model of discrete connected new-type precast reinforced concrete diaphragm in orthogonal slab laying direction, which is vitally important for foundation of the vertical bearing capacity and deformation calculation method. The deflection and crack distribution patterns infer that the discrete connected new-type precast reinforced concrete diaphragm processes the deformation characteristic of two-way slab floor, which can provide a basis for the theoretical analysis of discrete connected new-type precast reinforced concrete diaphragm.

scholarly journals Simple Laminated Glass Panels with Embedded Point Connection under Short-Term Load

2021 ◽  
Vol 1203 (2) ◽  
pp. 022079
Author(s):  
Michaela Zdražilová ◽  
Zdeněk Sokol ◽  
Martina Eliášová
Keyword(s):  
Bearing Capacity ◽  
Glass Structure ◽  
Structure Design ◽  
Laminated Glass ◽  
Glass Panel ◽  
Short Term ◽  
Load Bearing Capacity ◽  
Ongoing Research ◽  
Load Bearing ◽  
Glass Panels

Abstract Glass is a very attractive material for contemporary architecture. The trend is to achieve a maximum transparency of structures; therefore it becomes common to use glass as a material for load-bearing structural elements. Glass facades, roofs, beams or columns are widely used in buildings. The problematic part of a glass structure design is the connection between the glass pieces or between the glass elements and substructures from another material (e.g. steel, concrete etc.). The connection must be capable of bearing the stresses performing during the lifetime period and it should be as unobtrusive as possible at the same time. The ongoing research at the Faculty of Civil Engineering of the Czech Technical University in Prague is focused on an embedded laminated point connection for glass structures. Within this research, the real-scale glass panels were tested. The samples consisted of two glass plies bonded with the EVA foil. For the undrilled ply, the float glass was used in all cases. The thermally toughened or the heat strengthened glass was used for the pre-drilled ply. There was one embedded steel countersunk bolt with HDPE liners placed in each corner of the sample. During the experiment, the samples were horizontally placed using the embedded bolts. The load-bearing capacity of the six tested specimens was determined. The load was applied in several loading and unloading cycles until the collapse of the first embedded connection. If the glass panel failed before the connection, the sample was completely unloaded and then the load was gradually increasing until the collapse of the connection. Vertical deflection and the stresses at two different points were measured during the loading cycles. The humidity and the temperature were also monitored. The experiment showed the way of collapse and a short-term load-bearing capacity of a laminated glass panel with four embedded point connections.

scholarly journals The Influence of Improved Strength Grading In Situ on Modelling Timber Strength Properties

Buildings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 30
Author(s):  
Maria Loebjinski ◽  
Wolfgang Rug ◽  
Hartmut Pasternak
Keyword(s):  
Bearing Capacity ◽  
Strength Properties ◽  
Material Strength ◽  
Timber Species ◽  
Load Bearing Capacity ◽  
Visual Evaluation ◽  
Load Bearing ◽  
Existing Structures ◽  
Ultrasonic Time

The management and preservation of structures in our built environment are central and challenging tasks for practicing engineers. Within the CEN member states (European Committee for Standardization), the so-called Eurocodes form the basis of the design and verification of the load-bearing capacity of structures. Current Eurocodes do not contain special recommendations for existing structures, meaning that the principles for new structures are applied. This can lead to an incorrect estimation of the load-bearing capacity within the semi-probabilistic safety concept. A central task within the investigation and evaluation of existing structures is the strength grading of the material in situ using non-/semi-destructive technical devices. Studies show the potential of the ultrasonic time-of-flight measurement in combination with visual evaluation for an improved grading. The information on the material from an improved grading technique can be used to update the material parameters as a target variable using a measured reference variable. In this contribution, test data from a partner project (spruce, pine, and oak) are analyzed, applying the stochastic grading model of Pöhlmann and Rackwitz. It can be shown that different grading techniques influence the updated distribution function of the material strength within the grade. The results depend on the timber species. Perspectives to develop updated models dependent on the knowledge available are shown and discussed.

scholarly journals LOAD-BEARING CAPACITY ANALYSIS FOR STRUCTURAL COLD-FORMED MEMBERS SUBJECTED TO CENTRAL COMPRESSION

2021 ◽  
pp. 28-42
Author(s):  
А.V. Perelmuter ◽  
◽  
V.V. Yurchenko ◽  
Keyword(s):  
Bearing Capacity ◽  
Local Buckling ◽  
Structural Members ◽  
Design Code ◽  
Distortional Buckling ◽  
Load Bearing Capacity ◽  
Cross Sectional ◽  
Load Bearing ◽  
Composite Section ◽  
Flexural Torsional Buckling

Abstract. The main purpose of the research was a deep analysis and verification of the consistency and completeness of the design code relating to calculation of load-bearing structural members made from cold-formed profiles. The work has been done in close connection with the implementation on the territory of Ukraine of this design code. The article has discussed and investigated the load-bearing capacity of structural members made of cold-formed profiles subjected to the action of central compression. A system of constraints has been presented, in which the strength and buckling constraints for thin-walled cold-formed column members are formulated, taking into account their possible post-buckling behavior, namely, the ability to resist external loads and effects even after the occurrence of the local buckling and/or distortional buckling phenomenon. The performed load-bearing capacity investigation has shown that for the mono-symmetric cold-formed profiles, the flexural-torsional buckling is determinative. For such cold-formed profiles, the effect of the overall dimensions ratio (flange width to web height) on the load-bearing capacity of cold-formed profiles has been estimated. It has been shown that for the same cross-sectional area the load-bearing capacity of a column structural member made from cold-formed profile and subjected to axial compression can be significantly increased by assigning an optimal ratio of flange width to web height. The paper also has presented the results of the load-bearing capacities for the structural cold-formed members subjected to central compression, calculated according to the design standard DSTU-N B EN 1993-1-3: 2012 and according to the design code DBN V.2.6-198: 2014. It has been shown that in some cases the difference in the assessment of the load-bearing capacity for such structural cold-formed members reached 25%. A comparison of the load-bearing capacities for the action of the central compression has been made for structural cold-formed members made from a C-shaped profile and with a composite section of two C-shaped profiles. It has been shown that the load-bearing capacity of the structural cold-formed member of the composite section exceeds the load-bearing capacity of the member with single C-shaped profile by more than 3 times, while cross-section areas of these structural members differ only doubly.

scholarly journals Concrete-filled round-ended steel tubular stub columns under concentric and eccentric loads

2018 ◽  
Author(s):  
Ana Piquer Vicent ◽  
David Hernández-Figueirido ◽  
Carmen Ibáñez Usach
Keyword(s):  
Bearing Capacity ◽  
Mechanical Behaviour ◽  
Mechanical Response ◽  
Concrete Strength ◽  
High Strength ◽  
Load Bearing Capacity ◽  
Cross Sectional ◽  
Load Bearing ◽  
Composite Columns ◽  
Stub Columns

In the past, many works to study the mechanical behaviour of concrete filled steel tubular (CFST) stub columns have been conducted. Some of the applications of these composite columns oblige to meet higher requirements of ductility and load-bearing capacity. Traditionally, circular and rectangular tubes have been employed but recently new cross-sectional shapes of these composite columns are being designed and investigated with the aim of optimizing their mechanical behaviour. In this line, concrete-filled round-ended steel tubular columns (CFRT) have appeared as an alternative. However, the number of experimental programs to characterize their mechanical response is still scarce. In order to contribute to the test results database, in this paper an experimental study of 9 concrete-filled round-ended steel tubular stub columns is presented. All the specimens were designed with the same cross-sectional round-ended shape and have the same dimensions. In this program, both normal and high-strength concrete were employed as infill. During the tests, the columns were subjected to axial compression loads but under different eccentricities. The influence of eccentricity and concrete strength on the ultimate load bearing capacity of the concrete-filled round-ended steel tubular are discussed. Besides, the combined action of both components in this type of concrete-filled tubes as well as the effect of the concrete infill are studied.

scholarly journals The Effect of Service Installations on Structural Integrity of Slabs in Buildings

2010 ◽  
Vol 33 (1) ◽  
pp. 18-28
Author(s):  
Ladslaus Lwambuka
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Structural Design ◽  
Design Guidelines ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Structural Element ◽  
Load Bearing Capacity ◽  
Cross Sectional ◽  
Load Bearing

In building construction industry service installations, usually housed in conduit pipes, are commonly mounted inside reinforced concrete structural elements. This practice is adopted to attain aesthetical outlook at both interior and exterior surfaces of the buildings. Depending on the extent of service installations, the cross sectional area of the load bearing structural member is substantially reduced. However, the current structural design guidelines have no provision to accommodate the extent to which the existence of conduit pipes impairs the load bearing capacity of the structural element though reduced cross sectional area. This study has attempted to address this gap in structural design ofbuildings; it involves assessing the current design practice of considering a structural element as a full solid body and comparing its ultimate load bearing capacity with the ones containing the conduit pipes. The study findings are based on test results from laboratory experiments on reinforced concrete slab models with varying intensity of conduit pipeinstallations as commonly practiced on construction sites. Recommendations are put forth when and how to consider the reduced load bearing capacity through the existence of service installations as part of structural engineering designs.

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