Towards Simplified Tools for Analysis of Reinforced Concrete Structures Subjected to Impact and Impulsive Loading PDF Download

Author: Heather Trommels
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Andac Lulec
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
The analysis of reinforced and prestressed concrete elements under blast and impact loading is drawing the interest of many researchers due to increasing number of natural or human-made hazards that require attention. The analysis methods used are mainly based on either simplified single degree-of-freedom methods or highly sophisticated and complex hydrocodes. Although single degree-of-freedom methods are commonly used by designers for practical reasons, they are incapable of providing detailed results such as deformed shapes and crack maps. Additionally, since they require simplification of the structure to a single degree-of-freedom system, they are difficult to apply to complex geometries. On the other hand, hydrocodes overcome the limitations associated with the simplification of the structure. However, they require highly detailed models which require significantly increased modelling and computational time. Moreover, the accuracy of blast and impact analyses with hydrocodes heavily relies on the material input parameters which are not commonly known. Thus, there remains a need for accurate, simplified and reliable tools for analysis of reinforced and prestressed concrete subjected to blast and impact loading. The VecTor family of nonlinear finite element programs, using a macro-element smeared rotating crack approach, has been shown to be accurate in predicting the response of shear-critical structures under quasi-static conditions. In this study, two members of this suite, VecTor3 and VecTor6, were adapted for the blast and impact analyses of reinforced and prestressed concrete structures in 3D and axisymmetric conditions, respectively. The results obtained from the simulations were close to those experimentally observed. Additionally, a semi-analytical formula for the prediction of perforation velocity from missile impact was developed. The formula, which is based on the Modified Compression Field Theory, considers the influence of longitudinal and shear reinforcement in the target differently from other commonly used empirical formulae. The formula was validated with numerous missile impact data available in the literature, and good accuracy was found.

Author: Rasekh Rahim Zadeh
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 138

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Reinforced concrete is one of the prime building materials widely used to construct protective structures. One of the purposes of this project is to study the non-linear response of reinforced concrete structures when subjected to impact and blast loading. The study is conducted at two levels: material level and structural level. At the material level, the strength enhancement of three material models of LS-DYNA subjected to high strain rates is studied. The effects of strain rate and lateral inertial confinement on the strength enhancement are investigated. Recommendations are made to improve the accuracy of the results of future numerical simulations for reinforced concrete structures subjected to loads having high strain rates. At the structural level, Pressure-Impulse diagrams for reinforced concrete columns that have four configurations of transverse reinforcement are developed. Finite element modeling in LS-DYNA is used to analyze the structures and calculate the damage level for each blast event. The developed Pressure-Impulse diagrams are used to study the effect of confinement on the reduction of damage level at impulsive, dynamic, and quasi-static loading conditions.

Author: Holm Altenbach
Publisher: Springer
ISBN: 9783662557709
Category : Science
Languages : en
Pages : 0

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This Encyclopedia covers the entire science of continuum mechanics including the mechanics of materials and fluids. The encyclopedia comprises mathematical definitions for continuum mechanical modeling, fundamental physical concepts, mechanical modeling methodology, numerical approaches and many fundamental applications. The modelling and analytical techniques are powerful tools in mechanical civil and areospsace engineering, plus in related fields of plasticity, viscoelasticity and rheology. Tensor-based and reference-frame-independent, continuum mechanics has recently found applications in geophysics and materials.

Author: Venkatesh K.R. Kodur
Publisher: DEStech Publications, Inc
ISBN: 1605952273
Category : Technology & Engineering
Languages : en
Pages : 1014

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Original research on performance of materials under a wide variety of blasts, impacts, severe loading and fireCritical information for protecting buildings and civil infrastructure against human attack, deterioration and natural disastersTest and design data for new types of concrete, steel and FRP materials This technical book is devoted to the empirical and theoretical analysis of how structures and the materials constituting them perform under the extreme conditions of explosions, fire, and impact. Each of the 119 fully refereed presentations is published here for the first time and was selected because of its original contribution to the science and engineering of how materials, bridges, buildings, tunnels and their components, such as beams and pre-stressed parts, respond to potentially destructive forces. Emphasis is placed on translating empirical data to design recommendations for strengthening structures, including strategies for fire and earthquake protection as well as blast mitigation. Technical details are provided on the development and behavior of new resistant materials, including reinforcements, especially for concrete, steel and their composites.

Author:
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ISBN:
Category :
Languages : en
Pages :

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Author: Jitesh Kumar Reddy Nalagotla
Publisher:
ISBN:
Category : Blast effect
Languages : en
Pages : 93

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Reinforced concrete slab systems are widely used in protective structures designed to resist blast events. Blast events subject structures to high pressure and impulse loads. The magnitude of blast load experienced by a structural element is directly related to the exposed area. Hence protection of reinforced concrete slabs and walls, which constitute the maximum exposed area of a structure when subjected to blast loads, is of great importance. The main purpose of the project is to study the non-linear response of reinforced concrete slabs when subjected to impact and blast loading. Blast loading comprises of impulsive, dynamic and quasi-static loading conditions. And the performance of reinforced concrete slabs subjected to these loads is highly dependent upon the reinforcing steel provided in the slab. Hence a comprehensive analysis is performed on a representative slab panel with varying reinforcement. Due to the nature of the blast loading analysis method used influences the slab response significantly. Hence the slab response was predicted and compared using finite element (FE) and single degree of freedom (SDOF) methods. An advanced finite element modeling tool, LSDYNA and a commonly used SDOF analysis tool, SBEDS are employed for the purpose of analysis. A parametric analysis is conducted to develop Pressure-Impulse (PI) curves for different damage levels. Curve fit analysis was performed to characterize the PI curves generated from FE method. Conclusions and future work recommendations are presented for design of reinforced concrete slabs for blast protection based upon the research are presented and discussed.abstract.

Author: R. I. Gilbert
Publisher: Elsevier Publishing Company
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 344

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The inability of designers of concrete structures to recognize and quantify the non-linear effects of cracking, creep and shrinkage is a common cause of serviceability failure. Such failures include excessive deflection, camber and/or shortening of members and excessive cracking which may cause aesthetic or durability problems. This book provides practising engineers with practical and usable techniques for predicting the non-linear effects of creep and shrinkage on the in-service behaviour of concrete structures. Both cracked and uncracked reinforced, prestressed, and composite members subjected to sustained loads or sustained deformations are considered. Analytical procedures are developed for the calculation of instantaneous and time-dependent stresses and deformations on cross-sections in both simple and continuous members. Numerous self-contained worked examples which clearly illustrate the analytical procedures are included. A wide variety of practical situations is considered. Listings of microcomputer programs for a number of the analyses are also presented.

Author: Reda Bou-Hamdan
Publisher:
ISBN:
Category :
Languages : en
Pages : 38

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Author: A. Feldman
Publisher:
ISBN:
Category : Strength of materials
Languages : en
Pages : 1

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An investigation was made to obtain, by means of tests, information which will contribute to a better understanding and more accurate prediction of the strength and behavior of reinforced concrete structhavior of simple-span reinforced concrete beams subjected to impulsive loading. To accomplish this, tests of beams and of reinforcing bar coupons were made and the resulting data analyzed. The practicability of an existing method of computing the resistance of dynamically loaded reinforced concrete beams was also checked. To this end, comparisons were made between the test results and the pres subjected to dynamic loading. The immediate objective was the determination of the resistance and behavior of simple-span reinforced concrete beams subjected to impulsive loading. To accomplish this, tests of beams and of reinforcing bar coupons were made and the resulting data analyzed. The practicability of an existing method of computing the resistance of dynamically loaded reinforced concrete beams was also checked. To this end, comparisons were made between the test results and the prediction of the method of analysis. (Author).