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Simulations of the response of concrete structures subjected to air blasts

Svantesson, Peter LU (2013) In TVSM VSM820 20131
Structural Mechanics
Abstract
The response of concrete structures subjected to blast load can be studied numerically using commercial finite element programs. The complexity of reinforced concrete makes modeling and simulation of large structures time and computer power consuming. Consequently, The Swedish Defense Research Agency, FOI, has an interest in finding a fast and numerically efficient model to study this response to a reasonable cost.

A FOI report investigates the possibility to use a simplified numerical model of reinforced concrete slabs to simulate the response from blast loads and quasi static loads. The model is based on three-dimensional solid elements and a combined concrete/steel material model. The results are compared to an experimental study.

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The response of concrete structures subjected to blast load can be studied numerically using commercial finite element programs. The complexity of reinforced concrete makes modeling and simulation of large structures time and computer power consuming. Consequently, The Swedish Defense Research Agency, FOI, has an interest in finding a fast and numerically efficient model to study this response to a reasonable cost.

A FOI report investigates the possibility to use a simplified numerical model of reinforced concrete slabs to simulate the response from blast loads and quasi static loads. The model is based on three-dimensional solid elements and a combined concrete/steel material model. The results are compared to an experimental study.

This thesis introduces a further simplified model of the concrete slabs based on shell element formulation. A combined concrete/steel material model for shell and beam type elements is used. Layered design is used where the reinforcement is smeared over a layer corresponding to the allocation of the longitudinal bars. The introduced model is used to simulate a part of a multi-story building subjected to blast load. The results are compared to existing results from experiments performed on structures in 1:4 scale.

Simulations of the slabs using a shell element formulated model shows that the shell model can predict the response of a blast load with similar accuracy as the solid element formulated model. For two different charge weights, the maximum deflection is however 1.6 and 2.2 times bigger than the results from experiments. The shell element formulated slab predicts a fair response from quasi static loads, but not with the same accuracy as the solid element slab.

Simulations of the multi-story building shows a façade mean deflection 3.0 times bigger than the experimental results. Additionally, the deflection remains permanent as opposed to the experiment where the permanent deformation is close to zero.

The introduced model is deemed to be able to constitute a base for further studies of simulations with shell element formulated concrete structures. A first step would be to introduce a more correct blast load for a better evaluation of the response. (Less)
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author
Svantesson, Peter LU
supervisor
organization
course
VSM820 20131
year
type
H3 - Professional qualifications (4 Years - )
subject
keywords
Load blast, reinforced concrete, structural response, finite element analysis, LS-DYNA, LOAD BLAST ENHANCED, shell element
publication/series
TVSM
report number
TVSM-5193
ISSN
0281-6679
language
English
id
4220125
alternative location
http://www.byggmek.lth.se/
date added to LUP
2014-10-24 13:54:27
date last changed
2014-10-24 13:54:27
@misc{4220125,
  abstract     = {The response of concrete structures subjected to blast load can be studied numerically using commercial finite element programs. The complexity of reinforced concrete makes modeling and simulation of large structures time and computer power consuming. Consequently, The Swedish Defense Research Agency, FOI, has an interest in finding a fast and numerically efficient model to study this response to a reasonable cost.

A FOI report investigates the possibility to use a simplified numerical model of reinforced concrete slabs to simulate the response from blast loads and quasi static loads. The model is based on three-dimensional solid elements and a combined concrete/steel material model. The results are compared to an experimental study.

This thesis introduces a further simplified model of the concrete slabs based on shell element formulation. A combined concrete/steel material model for shell and beam type elements is used. Layered design is used where the reinforcement is smeared over a layer corresponding to the allocation of the longitudinal bars. The introduced model is used to simulate a part of a multi-story building subjected to blast load. The results are compared to existing results from experiments performed on structures in 1:4 scale.

Simulations of the slabs using a shell element formulated model shows that the shell model can predict the response of a blast load with similar accuracy as the solid element formulated model. For two different charge weights, the maximum deflection is however 1.6 and 2.2 times bigger than the results from experiments. The shell element formulated slab predicts a fair response from quasi static loads, but not with the same accuracy as the solid element slab.

Simulations of the multi-story building shows a façade mean deflection 3.0 times bigger than the experimental results. Additionally, the deflection remains permanent as opposed to the experiment where the permanent deformation is close to zero.

The introduced model is deemed to be able to constitute a base for further studies of simulations with shell element formulated concrete structures. A first step would be to introduce a more correct blast load for a better evaluation of the response.},
  author       = {Svantesson, Peter},
  issn         = {0281-6679},
  keyword      = {Load blast,reinforced concrete,structural response,finite element analysis,LS-DYNA,LOAD BLAST ENHANCED,shell element},
  language     = {eng},
  note         = {Student Paper},
  series       = {TVSM},
  title        = {Simulations of the response of concrete structures subjected to air blasts},
  year         = {2013},
}