ORCID Profile
0000-0001-5881-5112
Current Organisations
University of Adelaide
,
National Cheng Kung University
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Publisher: Thomas Telford Ltd.
Date: 12-2016
Abstract: Serviceability failures in reinforced concrete elements that are the result of excessive cracking or deflection are relatively common, particularly for slender sections such as slabs. The calculation of member deflection is typically carried out by applying an elastic deflection equation with an effective flexural rigidity that is a function of the full-interaction uncracked and cracked flexural rigidities. The effective flexural rigidity achieves two purposes: it allows for variations in cracking along the member length and approximates tension stiffening, that is slip between the reinforcement and adjacent concrete, as this is not accounted for in standard full interaction analyses. Although much research has been conducted to define effective flexural rigidity, the resulting equations are typically empirical calibrations or allow for bond without allowing for bond slip. In this paper, a new partial-interaction approach for quantifying the flexural rigidity of a cracked section based on a recently developed segmental analysis procedure is presented. It is shown that the partial-interaction cracked flexural rigidity is independent of the applied moment after the onset of cracking. Hence, for a given cross-section, the effective flexural rigidity only varies with the proportion of the member which is cracked.
Publisher: Informa UK Limited
Date: 20-04-2201
Publisher: Elsevier BV
Date: 03-2018
Publisher: Elsevier BV
Date: 03-2018
Publisher: Wiley
Date: 29-08-2018
Publisher: American Society of Civil Engineers (ASCE)
Date: 10-2018
Publisher: Wiley
Date: 08-2018
Publisher: Wiley
Date: 27-03-2020
Abstract: The redistribution of moment within a statically indeterminate reinforced concrete beam at the ultimate limit state occurs through variations in the flexural rigidities and through the formation of hinges. The phenomena of moment redistribution (MR) is used to increase the efficiency of reinforced concrete design by allowing moments to be transferred away from critical cross sections thereby resulting in lower design moments. To allow for this effect in design, two main approaches are adopted. The first is to perform an elastic analysis and then to adjust the resulting distribution of moment using a codified MR factor. The second is to apply a plastic analysis allowing for the formation of hinges, and to calculate the rotational requirements at the hinges from first principles. This paper uses fundamental plastic analyses to derive closed‐form expressions for the hinge rotational requirements for full MR (that required to achieve the theoretical maximum applied load within the beam based on the moment capacity of sections within the beam). These closed‐form solutions are then used to quantify the maximum load on a beam when the rotational capacities at a hinge are less than the rotational requirements for full MR (partial MR). Closed‐form solutions are then used to derive MR factors which do not require semimechanical calibration.
Publisher: Informa UK Limited
Date: 12-09-2022
Publisher: Wiley
Date: 11-08-2023
Abstract: In reinforced concrete elements, tension‐stiffening strongly influences deflections and crack‐widths at the serviceability limit, and plastic hinge rotation at the ultimate limit. Modeling has shown the impact of tension‐stiffening at the ultimate limit to be particularly important when ultimate failure is governed by reinforcement rupture, which has been is common in ultra‐high performance fiber reinforced concrete (UHPFRC) elements. It is further known that the magnitude of tension‐stiffening and crack opening is proportional to both the reinforcement ratio of the tension chord and the diameter of the reinforcing bar. Despite this understanding, very little testing has been undertaken to quantify the bond between larger diameter reinforcement and UHPFRC and also on the resulting impact to tension‐stiffening and concrete cracking. To address these issues, in this paper a series of bond and tension‐stiffening tests are undertaken on ultra‐high performance concretes both with and without steel fibers. The result of the experiments is used to develop a local bond stress slip relationship applicable to both pre‐ and post‐yield. When implemented in a partial‐interaction model, it is shown that the new bond model can be used to predict pre‐ and post‐yield tension‐stiffening and crack‐widths.
Publisher: Wiley
Date: 10-07-2019
Publisher: American Society of Civil Engineers (ASCE)
Date: 08-2018
No related grants have been discovered for Alexander Sturm.