Description of shell, plate, membrane and solid elements.

1. ETABS
MODELLING
AUTHOR:
VALENTINOS
NEOPHYTOU
BEng
(Hons),
MSc
March
2013

2. ETABS MODELING PARAMETERS
Description of elements type
Membrane
element
• Ignore
bending
stiffness
• Tension
/
Compression
• In-­‐
plane
Shear
• For
in
plane
loads
• Principle
Stresses
• suitable
for
very
thin
structures
/
members
• Thin
Walled
Shells,
• Specially
Suitable
for
Ferro
Cement
Structure
Plate
• Primarily
Bending
mode
• Moment
and
Shear
are
predominant
• Suitable
for
moderately
thick
slabs
and
plates
• For
Out-­‐of-­‐plane
loads
only
• Can
be
used
in
3D
or
2D
models
• Suitable
for
planks
and
relatively
flat
structures
Shell
• Combined
Membrane
and
Plate
• Suitable
for
general
application
to
surface
structures
• Suitable
for
curved
structures
• Thick
shell
and
thin
shell
implementations
available
• Membrane
thickness
and
plate
thickness
can
be
specified
separately
• Numerous
results
generated.
Difficult
to
design
the
section
for
combined
actions
Solid
Valentinos Neophytou BEng (Hons), MSc
Page: 2
ETABS MANUAL

3. ETABS MODELING PARAMETERS
• Shear
Axial
deformation
mode
in
3D
• Suitable
for
micro-­‐models
• Suitable
for
very
thick
plates
/
solids
• May
not
be
applicable
much
to
ferocement
structures
• Use
6
to
20
node
elements
Analysis
type
according
to
FEA
method
Non
linear
analysis
Dynamic
analysis
• P-­‐Delta
Analysis
• Free
Vibration
and
Modal
Analysis
• Buckling
Analysis
• Response
Spectrum
Analysis
• Static
Pushover
Analysis
• Steady
State
Dynamic
Analysis
• Fast
Non-­‐Linear
Analysis
(FNA)
• Large
Displacement
Analysis
Non-­‐linear
response
may
be
produced
by:
The
response
is
directly
proportional
to
excitation
– Geometric
Effects
(Geometric
(Deflection
doubles
if
load
is
doubled)
non-­‐linearity)
– Material
Effects
(Material
non-­‐
linearity)
– Both
Valentinos Neophytou BEng (Hons), MSc
Page: 3
ETABS MANUAL

4. ETABS MODELING PARAMETERS
Results
Load transfer of slabs and beams
Valentinos Neophytou BEng (Hons), MSc
Page: 4
ETABS MANUAL

5. ETABS MODELING PARAMETERS
Define slab
One way slab modelling can be use in the following case:
• By default use one-way load transfer mechanism
• Generally used to model pre-cast slabs
• Can also be simple RC solid slab
Valentinos Neophytou BEng (Hons), MSc
Page: 5
ETABS MANUAL