Predicting reinforced concrete response to blast loads

2013 ◽  
Vol 40 (5) ◽  
pp. 427-444 ◽  
Author(s):  
Eric Jacques ◽  
Alan Lloyd ◽  
Murat Saatcioglu
Keyword(s):  
Reinforced Concrete ◽  
Shock Tube ◽  
Free Field ◽  
Computer Software ◽  
Deformation Characteristics ◽  
Structural Members ◽  
Pressure Impulse ◽  
Concrete Members ◽  
Inelastic Analysis ◽  
Wide Range

Computer software was developed for inelastic analysis of structural members subjected to blast-induced shock waves. The software can predict the dynamic response of structural elements, provided the load–deformation characteristics are defined. The software has built-in capabilities to generate the load–deformation characteristics of common structural and non-structural members. Currently this capability includes reinforced concrete columns, one-way walls, beams, and one-way slabs. The input consists of member geometry, boundary conditions, dynamic material properties, explosive threat parameters, and desired performance levels. The results are presented in graphical format in terms of structural load–deformation characteristics, single degree of freedom displacement – time histories and iso-displacement pressure–impulse diagrams. The program was verified extensively using experimental data generated from simulated explosive loading of reinforced concrete members at the University of Ottawa shock tube testing facility. The shock tube has been shown to generate a wide range of pressure–impulse combinations, accurately simulating free-field detonation of high explosives of various mass and standoff distances.

scholarly journals Temperature influence on creep of reinforced concrete

2020 ◽  
Vol 13 (6) ◽  
Author(s):  
Edmilson Lira Madureira ◽  
Brenda Vieira Costa Fontes
Keyword(s):  
Reinforced Concrete ◽  
Moisture Content ◽  
Alternative Model ◽  
Sustained Load ◽  
Structural Members ◽  
Temperature Influence ◽  
Stress Increase ◽  
Concrete Members ◽  
Over Time ◽  
Creep Strains

abstract: The creep of concrete promotes strains over time in structural members kept under sustained load. It causes the stress decrease on the concrete and the steel stress increase in reinforced concrete members. The moisture content and temperature influence significantly such phenomenon. The creep strains model of the NBR 6118/2014 [1] is, applicable, solely, to those cases of constant stress magnitudes. Reinforced concrete members exhibit variations on the stress magnitudes and, in this way, requires the use of an alternative model for the prediction of the creep strains as the so known the State Model. This report refers itself to temperature influence analysis upon creep strains of reinforced concrete structural members. The results have revealed that temperature speeds up the creep effects and, in this way, the steel yielding caused by the stress increase on the reinforcement bars occurs at earlier ages.

scholarly journals Numerical simulation of the experimental behavior of RC beams at elevated temperatures

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Camille A. Issa ◽  
Ramezan A. Izadifard
Keyword(s):  
Reinforced Concrete ◽  
High Temperatures ◽  
Elevated Temperatures ◽  
Material Behavior ◽  
Reinforced Concrete Beams ◽  
Structural Members ◽  
Fire Event ◽  
Concrete Material ◽  
Concrete Members ◽  
Actual Fire

AbstractThe danger of fire is present always and everywhere. The imminent danger depends upon the actual type and length of fire exposure. Reinforced concrete structural members are loadbearing components in buildup structures and are therefore at high risk, since the entire structure might potentially collapse upon their failure. Thus, it is imperative to comprehend the behavior of reinforced concrete members at high temperatures in case of fire. In this study, the mechanical properties of concrete exposed to high temperatures were experimentally determined through the testing of 27 concrete cylinder starting at room temperature and increasing up to 260 °C. The concrete material behavior was implemented into the ABAQUS software and a finite simulation of reinforced concrete beams exposed to actual fire conditions were conducted. The finite element models compared favorably with the available experimental results. Thus, providing a valuable tool that allows for the prediction of failure in case of a fire event.

scholarly journals Seismic Behavior of Reinforced Concrete Members Built with Recycled Aggregate

2019 ◽  
Vol 2 (2) ◽  
pp. 295-306
Author(s):  
Alper Ilki ◽  
Ilyas Saribas ◽  
Caglar Goksu
Keyword(s):  
Reinforced Concrete ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Small Scale ◽  
Concrete Aggregate ◽  
Structural Members ◽  
Recycled Concrete Aggregate ◽  
Rapid Urbanization ◽  
Concrete Members ◽  
Waste Concrete

In connection with rapid urbanization and earthquakes, a huge number of structures have been demolished and generated lots of waste concrete for the last 40 years. Studies on the reclamation of the waste concrete is a pioneer subject for construction sectors in the world. Since the recycling of the waste concrete and reusing of recycled concrete aggregate in the production of new concrete is an important issue for saving of natural resources, economic, sustainable development, significant number of studies have been carried out on this subject. In the scope of this study, a literature review is conducted on the effect of recycled concrete aggregate on mechanical and durability characteristics of small-scale members. Furthermore, structural and seismic performances of full-scale reinforced concrete structural members produced with recycled concrete aggregate are discussed. The test results indicated that the structural members containing recycled aggregate exhibited similar structural performance with their counterparts containing natural aggregates. It was also observed that recycled concrete aggregate did not seem to have an adverse effect on seismic characteristics of the structural members such as ductility.

SHEAR REPAIRED RC BEAM BY FRP BONDING WITH EXTERNAL POST-TENSIONING

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Rumana Choudhury ◽  
T.G. Suntharavaivel ◽  
Nirmal Mandal
Keyword(s):  
Reinforced Concrete ◽  
Shear Capacity ◽  
Rc Beams ◽  
Structural Members ◽  
Shear Cracks ◽  
Shear Strengthening ◽  
Flexural Strengthening ◽  
Concrete Members ◽  
Post Tensioning ◽  
Strengthening Technique

Various factors, including increase in traffic volume and weight, structural aging, and environmental impact, cause damage in structural members. This raises the importance of the maintenance, rehabilitation, and strengthening of reinforced concrete members. External post-tensioning is one of the widely-used strengthening techniques in many countries due to its advantages over other strengthening methods. Although flexural strengthening of existing structural members is a well-established method, shear strengthening of structural members, especially with existing shear cracks, has attained very little attention from researchers. Similarly, external fiber-reinforced polymer (FRP) bonding for shear strengthening of structural members, especially with existing shear cracks, is a relatively new area of research. This paper presents the results of an experimental study on the shear strengthening of reinforced concrete (RC) beams with existing shear cracks by external post-tensioning and external FRP bonding. The test result showed that the combined strengthening technique of external post-tensioning and external FRP bonding can effectively increase the shear capacity of RC beams with existing shear cracks.

scholarly journals Predicting shear failure in reinforced concrete members using a three-dimensional peridynamic framework

2021 ◽  
Author(s):  
Mark Hobbs ◽  
Gabriel Hattorri ◽  
John Orr
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Shear Failure ◽  
Load Transfer ◽  
Three Dimensional ◽  
Constitutive Law ◽  
Concrete Members ◽  
Predictive Error ◽  
Wide Range ◽  
Transfer Mechanisms

The assumptions made in design codes can result in unconservative predictions of shear strength for reinforced concrete members. The limitations of empirical methods have prompted the development and use of numerical techniques. A three-dimensional bond-based peridynamic framework is developed for predicting shear failure in reinforced concrete members. The predictive accuracy and generality of the framework is assessed against existing experimental results. Nine reinforced concrete beams that exhibit a wide range of failure modes are modelled. The shear-span-to-depth ratio is systematically varied from 1 to 8 to facilitate a study of different load-transfer mechanisms and failure modes. A comprehensive validation study such as this has until now been missing in the peridynamic literature. A bilinear constitutive law is employed, and the sensitivity of the model is tested using two levels of mesh refinement. The predictive error between the experimental and numerical failure loads ranges from +3% to -57%, highlighting the importance of validation against a series of problems. The results demonstrate that the model captures many of the factors that contribute to shear and bending resistance. New insights into the capabilities and deficiencies of the peridynamic model are gained by comparing the expected load-transfer mechanisms with the predictive error.

scholarly journals Exploitation of Ultrahigh-Performance Fibre-Reinforced Concrete for the Strengthening of Concrete Structural Members

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Mohammed A. Al-Osta
Keyword(s):  
Reinforced Concrete ◽  
Environmental Conditions ◽  
Design Guidelines ◽  
Fibre Reinforced Concrete ◽  
Structural Members ◽  
Structural Concrete ◽  
Concrete Members ◽  
Service Load ◽  
Durability Performance ◽  
Load Conditions

The repair and strengthening of reinforced concrete members are very important due to several factors, including unexpected increases in load levels and/or the damaging impact of aggressive environmental conditions on structural concrete members. Many researchers have turned to using materials for the repair and strengthening of damaged structures or the construction of new concrete structural members. Ultrahigh-performance fibre-reinforced concrete (UHPFRC), characterized by superior structural and durability performance in aggressive environmental conditions, is one of the materials that have been considered for the repair and strengthening of concrete structural members. The repair or strengthening of concrete structures using UHPFRC needs a thorough knowledge of the behaviour of both the strengthening material and the strengthened concrete structure at service load conditions, in addition to an understanding of the design guidelines governing the use of such materials for effective repair and strengthening. In this study, the recent issues and findings regarding the use of UHPFRC as a repair or strengthening material for concrete structural members are reviewed, analysed, and discussed. In addition, recommendations were made concerning areas where future attention and research on the use of UHPFRC as a strengthening material needs to be focused if the material is to be applied in practice.

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