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ANSYS CivilFEM Bridge Webinar

P t R B tt M S C E P EPeter R. Barrett, M.S.C.E., P.E.

© 2009 CAE Associates

ANSYS + CivilFEM

Challenges of Bridge Engineers today:— Increase Construction efficiency— Design and Build to Save Material Costs— Extend the life of existing bridgesg g— Better Empower a shrinking engineering workforce

Solution Solution— Develop more accurate representation of the structural response:

• Nonlinear analysis and incremental construction are ANSYS/CivilFEM strengths

D l t t d l t d i ti— Develop automated analyses to save design time— Perform what if and design optimization tasks to create more effective

use of construction materials

2

CAE Associates – CivilFEM / ANSYS Partner

The world’s biggest and most sophisticated users of engineering simulation choose CAE Associates for consulting services, training and software. e.g. ABB, AREVA, Bechtel-Houston, GE (Nuclear, Energy, Aviation, GRC), Seimens, UTC (Pratt & Whitney, Otis, Sikorsky), AECOM, Westinghouse, Parsons….

Si th ’ i ti i 1981 h i li d i idi Since the company’s inception in 1981, we have specialized in providing solutions to engineering problems using FEA and CFD technology.

3

What is CivilFEM?

CivilFEM is an integrated Pre Solu and Post processor add on to CivilFEM is an integrated Pre- , Solu - and Post-processor add-on to traditional ANSYS developed by ANSYS’s Spain distributor INGECIBER

100º110º120º130ºAASHTO LRFDBridge Design Specifications

N /CivilSYS FEM

55

2.5

40

5

15

15

5

8060

50

60

5

5

5

2.5

5

2.5

60

CANADA

100º110º120130

50º

40º

30º

Bridge Design Specifications (Western USA)

Tropic of Cancer

52.5

2.5

MÉXICO

AAcceleration Coefficient

Seismic Zone

1

2

3

4> 0.29

> 0.19 and < 0.29

_> 0.09 and < 0.19

_

< 0.09

_

4

INGECIBER- CivilFEM Developer / ANSYS Partner

Ingeciber S.A. is a CAE company and ANSYS Channel Partner with more than 20 years of experience using and developingwith more than 20 years of experience using and developing CAE Software

Ingeciber’s Quality Assurance System is ISO 9001 certified. g Q y y

ANSYS, Inc. and Ingeciber, S.A. have a long standing OEM Agreement and established a strategic alliance for FEA solutions i h i i d S ld id Cin the construction industry. Some worldwide Customers:

5

ANSYS Today

World’s Largest Simulation CommunityWorld s Largest Simulation Community

>10,000 Total Customers

>125 000 Commercial Seats


>60 000 Commercial Seats


>10 000 Commercial Seats>125,000 Commercial Seats >140,000 University Seats > 200 Channel Partners > 75 Industry Partners

>60,000 Commercial Seats >70,000 University Seats >20 Channel Partners >80 Industry Partners

>10,000 Commercial Seats

6

ANSYS + CivilFEM

ANSYS + CivilFEM combines the world leading general ANSYS + CivilFEM combines the world leading general purpose structural analysis features of ANSYS (ISO-9001) with high-end civil engineering-specific structural analysis capabilities of CivilFEM (ISO-9001).

7

Current CivilFEM Distributors

8

CAE Associates, Inc.

» One of first 4 ANSYS Channel Partners Since 1985…

» Engineering Co

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» Engineering Co. Since 1981

CAE Associates – CivilFEM / ANSYS Partner

25 years Structural Thermal and Fluid engineering consulting 25 years Structural, Thermal and Fluid engineering consulting One of the original ANSYS Channel partners The US leader in ANSYS Finite Element Training The US leader in ANSYS Finite Element Training Custom Training of ANSYS and CivilFEM

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Sampling of CAE Consulting Services

NIST – Structural Fire Response and Probable Collapse Sequence of the World Trade Center Towers Investigation

Steam Generator Replacement in Nuclear C t i t B ildi Containment Buildings

Pre-stressed Concrete Pipe Simulation Concrete Dam simulation to meet

FERC /C f E i li iFERC /Corps of Engineers licensing

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CAE Associates Senior Technical Staff

Nicholas M. Veikos, Ph.D., President

Peter R. Barrett, M.S.C.E., P.E., Vice President

Michael Bak, Ph.D., Project Manager

P t i k C i h M S M E P j t MPatrick Cunningham, M.S.M.E., Project Manager

Steven Hale, M.S.M.E., Project Manager

James Kosloski, M.S.M.E., Project Manager, , j g

Hsin-Hua Tsuei, Ph.D., CFD Manager

Jonathan Masters, Ph.D., Project Manager

George Bauer, M.S.M.E., Project Manager

Eric Stamper, M.S.M.E., Project Manager

Michael Kuron M S M E Project EngineerMichael Kuron, M.S.M.E., Project Engineer

Lawrence L. Durocher, Ph.D., Director

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ANSYS Strengths

Nonlinear Stress Analysis— Contact— Plasticity— Creep

L D fl i P D l Eff— Large Deflection – P-Delta Effects— Element Birth and Death

Full Element Library (over 200)B Pi & Sh ll— Beams, Pipes & Shells

— 2D and 3D Solids— Springs, Contact, etc

Dynamic Analysis— Response Spectrum— Nonlinear Transient Dynamics

Thermal-Stress Analysis— Indirect and direct coupled field simulations

Large Model Simulations

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Large Model Simulations— Solvers, meshing, Postprocessing, Graphics

CivilFEM Strengths

CivilFEM Capabilities CivilFEM Capabilities— Entire suite of ANSYS capabilities including nonlinear analysis

and dynamicsB ilt i M t i l M d l d C d Ch ki— Built-in Material Models and Code Checking

Industry Specific CivilFEM Modules— Nonlinear Bridge Simulation— Pre-stressed Concrete— Geotechnical Applications including tunnelling

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Geotechnical Applications including tunnelling— Nuclear Applications

CivilFEM & ANSYS

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CivilFEM –Help

Interactive Online Help Interactive Online Help Examples Manuals Advanced Workshops Training Courses

16

Bridges and N li iti Nonlinearities

Overview

Quote from Bridge Designer"ANSYS has always been a powerful tool in the resolution of advancedstructural problems such as arch buckling evolutive process etc Nowstructural problems, such as arch buckling, evolutive process, etc. Now,with the addition of CivilFEM, it has become a decisive instrument in theentire design and project of bridges such as our "Viaducto del Sil, enPonferrada (León, Spain)".

In the analysis of large bridges you must take into account a lot ofstructural features; different materials, types of section, constructionprocess,... CivilFEM Preprocessor is a definitive help to give ANSYS all thei f ti it dinformation it needs.

Later, CivilFEM Postprocessor allows you to check your model under severalInternational Codes and, both quickly and safely, confirming that thesolution proposed for the bridge is valid.

This whole process eventually concludes in a highly accurate answer to ourclients' requests, with considerable savings in the amount of time spent indeveloping the whole project and with a decisive saving of costs in theconstructed bridge.“Kind regards,Jorge Pérez Armiño

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A.T.P. Ingeniería, S.L.www.atp-ingenieria.es

Bridge Module Main Features

Utilities for generating common bridge sections and layout design

Bridge layout modelling (in plan and elevation view) Geometric and finite element model generation with g

either Beams or Shells or 3d Solid elements including wizards for

• Suspension bridges• Arch bridges• Cable-Stayed bridges

Load Generation— Overloads— Moving loads (vehicle’s editor)— Utility for Automated Prestressed force input— User loads— Automatic Load combinations

Simulation of construction process

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p Concrete Creep and Shrinkage

Section Definition

Using the Bridge Section explorer (Slab or Box) Using the Bridge Section explorer (Slab or Box)

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Slab Section Definition

Slab section types

RSBTOP

BMTTOP

Slab section types

Rectangular section Trapezoidal section with flangesB

DEPTH DEPTH

BBOTTBOT TF

BTOP

BBOT

DEPTH

TTOPTS

TBOT BBOT

BM2

BM1

BTOP

DEPTH

TTOP

TMPS

BBOT

Trapezoidal section Polygonal section with two bends

BM2R

BTOPRBTOPLBM2L TTOPR

axis

BBOT

Polygonal Asymmetric with two bends Note: The upper line (deck) is always

BBOTR

BM1RBM1L

BBOTL

DEPTHL

TBOTL

TML

TBOTR

TMR DEPTHR

PA

21

Bridge Section Typeshorizontal. The slope must be laterdefined with the section’s bank.


Slab section definition window General Shape: Slab section definition window – General Shape:

S tiSections are defined by dimensions

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Holes are defined

Global size Cell dimensions

Holes are defined Mesh divisions are defined Supports are defined (3d Model)

HolesFlange

23

Box Section Definition

Box Section definition window:

Main dimensions are entered here.

After the initial After the initial shape has been created, the geometry g ywill be refined using step-by-step modification.

24


Modify Box Section dimensions:

CellSymmetry

Modify Box Section dimensions:

WebFlange

25


Modify Box Section dimensions: Modify Box Section dimensions: — Crown

26


Box Section window:

Global Size Top div

o Sect o do— Edit Mesh Divisions

Size Top div

Bottom

Web div

Bottom div

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It is important to note that all the cross sections defined must have the psame number of divisions (the same number of sub-elements). If not, the program will not be able to generate a swept mesh of the bridge automatically.

The program will not be able

1

2

123 The program will not be able

to mesh the bridge because the two cross section defined do not have the same number

3

4

5

4

of divisions5

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Box Section Definition - Script

! Defines a cross section in a box cross-section bridge.! Main Menu > CIVIL Preprocessor > Bridges Prep > Bridge Sections > Box!~BRSBOX, NSEC, MAT, NCEL, DEPTH, WDTCEL, THTOP, THBOT, THWEB, LFL~BRSBOX, 1, 1, 1, 2.5, 6.00, 0.25, 0.2, 0.5, 2.5 ~BRSMDF,1,NAME,,,Section 3! Main Menu > CIVIL Preprocessor > Bridges Prep > Bridge Sections > Modify!~BRSMDF,ICSEC, Lab1, Lab2, Lab3, VALUE, IDX1, IDX2, IDX3 ~BRSMDF, 1, BOX, KSYM, , -1!A=0.75/SQRT(2.50**2+0.75**2) ~BRSMDF,1,BOX,WEB,SLOPE,-A,0,0,0 ~BRSMDF,1,BOX,WEB,RATS,0.25,0,1,0~BRSMDF 1 BOX WEB SLPS 0 1 0 1 0BRSMDF,1,BOX,WEB,SLPS,0.1,0,1,0~BRSMDF,1,BOX,WEB,RATB,0.12,0,1,0~BRSMDF,1,BOX,WEB,SLPB,0.75,0,1,0~BRSMDF,1,BOX,WEB,RATB,0.2,0,3,0

BRSMDF 1 BOX WEB SLPB 0 49 0 3 0~BRSMDF,1,BOX,WEB,SLPB,0.49,0,3,0~BRSMDF,1,BOX,FLANGE,THICK,0.15,0,0,0 ~BRSMDF,1,BOX,WEB,RATS,1 ,1,1,0 ~BRSMDF,1,BOX,WEB,SLPS,0.1,1,1,0

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Layout Definition

Bridge layout is performed as follows: Bridge layout is performed as follows:— Define Angle units (only for the layout)— Definition of the mileage points that represent the structure

axisaxis• Typically read from a file

~BRINIP,1,0,0,0,0,0 ! Defines the MP and Ansys direction ! from which the bridge model is generated

~BRADDPL,99.5,153.5 ! bridge layout in plan view ~BRADDEL,99.5,153.5 ! bridge layout in elevation view~BRSKTCH,5 ! Plots the bridge axis (MP’s path)

! Example~BRINIP,1,~BRADDPL, 90,120, 0, 0~BRADDPL, ,170, 0,-200~BRADDEL, 90,170, 0, 0

— Definition of plan and elevation layout

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~BRADDPL MP1 MP2 Ri Rf ang

Layout in Plan View

~BRADDPL, MP1, MP2, Ri, Rf, ang

MP: initial and final “mileage point” R: initial and final curvature radiusR: initial and final curvature radius ANG: angle with respect to previous

sectionsection.

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Layout in Plan View

Plan view parameter definition

Case 1: Straight stretch, If a radio is infinite the field is not introduced, or the value zero is introduced.

Case 2: Circumference, If Ri = Rf Null:0

Case 3: Clothoid (double

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Case 3: Clothoid (doublespiral spline ), If Ri Rf

BRADDEL MP1 MP2 ii if

Layout in Elevation View

~BRADDEL, MP1, MP2, ii, if

MP: initial and final mileage point” point

II, IF: Slopes in % of the initial initial

And final MP of the stretch

ANG: angle respect to the previous stretch

33

Layout in Elevation View

Elevation view parameter definition

If II = IF the stretch, in elevation view, is a straight line then CivilFEM will fit a parabola

34

straight line then CivilFEM will fit a parabola.

Plot Sketch

35

~BRDEF, MP, Nsec, Yoffs, Zoffs, Bank, Trans, Skew, Solid

Solid Model

For the correct generation of the solid model and the finite element model of the structure, it is necessary to define a series of attributes. These attributes are:attributes are:

— Cross section number that will be assigned to the different mileage points (MP’s) forming the bridge. Offsets: Definition of the position of the intersection of the line of mileage— Offsets: Definition of the position of the intersection of the line of mileage points with the cross section plain (Yoffs, Zoffs), referred to the cross section coordinate system

— Bank: Possibility of defining the banks along the bridge.

yMP,s line

y g g g

z

Zoffs

Yoffs Bank (Rotation's center P)P

36

Bridge definition

Solid Model

Skew: This capability allows the definition of an offset angle of the cross Skew: This capability allows the definition of an offset angle of the cross section with respect to the road axis.

H ll lid i Thi bili ll h d fi h ll Hollow or solid section: This capability allows the user to define hollow or solid sections for a particular mileage point. Therefore, the user may consider hollow sections or solid section at particular points of the structure (at supports for example) (Only valid for slab cross section)structure (at supports, for example).(Only valid for slab cross-section)

Hollow section (Solid=0 or blank Solid section

According to original contour (Solid0)

37

Cross sections at supports

Solid Model

38

Model Generation

This utility generates the complete geometrical model of the structure as well as the finite element model from the cross sections definition (location, “offsets”, banks, etc)

— It is generated from the defined sections— It utilizes the previously defined layout— It generates the finite element model of either beams, shells

3 d b i k t ti llor 3-d bricks automatically

39

Bridge Wizards

Supported Bridges Supported Bridges— Concrete (with a CivilFEM bridge section)— Steel (with a CivilFEM steel 3D pattern)

Generic (with a CivilFEM generic cross section)— Generic (with a CivilFEM generic cross section)

Cable Stayed Bridges( ith Ci ilFEM b id ti )(with a CivilFEM bridge section)

Arch Bridges(with a CivilFEM bridge section)

— Beam model— Shell model

40

Bridge Wizards

Bridge Generators windows can generate 3D models for:Bridge Generators windows can generate 3D models for:

Concrete Suspension Bridges( ith Ci ilFEM b id ti )(with a CivilFEM bridge section)

Steel Suspension Bridges Steel Suspension Bridges(with a CivilFEM steel 3D pattern)

G i S i B id Generic Suspension Bridges(with a CivilFEM generic cross section)

Mixed section, two types of section:— Concrete slab over I-section steel beams — Concrete slab over a steel box

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— Concrete slab over a steel box

Suspension Bridge Generators

Concrete Suspension Bridgesp g

42

Supported Bridge Example

Supported Bridges :— Same parameters as suspension bridges are used, but only bridge deck will be

generated.

Concrete Steel

43

Loads Definition

In the bridge analysis process a great number of load steps In the bridge analysis process, a great number of load steps are automatically generated such that can easily be incorporated into load combinations

— Load types :• Mobile (vehicles, pedestrian, etc.)• Surface loads (structural, traffic, snow, etc.)( )• Prestressing, in any direction.• Self weight

— The loads generate LoadStates (LS) that are grouped in families and

LS 1

e oads ge e ate oadStates ( S) t at a e g ouped a es a dlater become combinations.

S

LS 2

LS 71

Vehicle Load

Family 19 Combination 19

44

LS 71

Loads Definition: Families

A family is a group of load states usually of the same A family is a group of load states, usually of the same topology.

All the load steps belonging to a family are combined into one unique load step according to their natureinto one unique load step according to their nature

The combined family can be later introduced as a starting point in load combinations. Load factor coefficients will be the same for each Load factor coefficients will be the same for each family

45

Loads Generation (Traffic Loads)

Vehicles: Rigid (truck) or flexible (train, adaptable to the path)g ( ) ( p p ) User friendly path definition: road surface and road axis are automatically

detected by the program

46

Loads Definition: Vehicles

Start End

Bridge deckFirst h l

Last vehicle vehicle

positionvehicle

position

It is possible to define when the vehicle movement starts and ends, relative to the bridge geometry.

47

Loads Generation (Prestressing Cables)

Definition of points along the cable’s path (automatic adjustment of the Definition of points along the cable s path (automatic adjustment of the points using splines)

Introduce the tensile force at specific locations in the tendon’s pathA tomatic transfer of the cable action to the str ct re Automatic transfer of the cable action to the structure

P' 1 P'N

P

P

PP

P1

2

k+2k+1

NPk

OP

Rz

MRz

MR Kfz

T1

1

3D spline generation x

RMR

y

x

c.d.g.R

y

Kfx

Kfy

T2

2

48

Transmision of the cable actions to the model

3D Tendon Geometry Editor

It allows the definition and edition of the geometric and strength properties It allows the definition and edition of the geometric and strength properties of all tendons of a structure. The geometry may be shown and edited either graphically or by coordinates.

Tool Bar

Elevation

Object Tree

Elevation View

Info/Edit Window

49

Plan View

Prestressed Forces, Moments & Stresses

Stresses in the support and in the middle of span.

50

Combinations with Variable Coefficients

Where should the two engines be located for the stress to be maximum at Where should the two engines be located for the stress to be maximum at point P?

? ? ?? ? ?

P

51


Mobile loads Mobile loads Combinations with variable coefficients (favorable/unfavorable) Actions in different directions (wind, earthquakes, …) Combinations according to codes logic

52

Combinations with Variable Coefficientsm

ost

e m

ost

e 1

ne2

Permanent actions (Gk)

ed in

the

msi

tion

ated

in t

hepo

siti

on

Virt

ual l

ane

Virt

ual l

an

Bord

er

Bord

er

Bord

er

( k)Self weight Dead load of 20 kN/m

Road traffic actions (Qk)

0kN

loca

tevo

rabl

e po

s

200k

N lo

cafa

vora

ble

pV V Vehicles (Double-axis)2x300 kN in virtual lane 12x200 kN in virtual lane 2

U if l di t ib t d l d

2x30

unfa

v

2x unf Uniformly distributed loads

9.0 kN/m2 in virtual lane 12.5 kN/m2 in virtual lane 22 5 kN/m2 in the other areas

Target:• Maximum MZ

2.5 kN/m in the other areas

53

Maximum MZ• Minimum MZ


Eurocode No 1: Permanent and transient situations (simplified) Eurocode No.1: Permanent and transient situations (simplified)

Permanent actions Variable actionsThe program will select

kQkG QG The program will select the coefficients to apply for each target and element.

Safety factorSafety factor y

for variable actions:

Q = 0 if it is favorable

y

for permanent actions:

G = 1.00 if it is favorable

Q = 1.00 if it is unfavorableG = 1.35 if it is unfavorable

54


Combination Rules are logic relations between Start States Combination Rules are logic relations between Start States. Each combination rule has its own Start States A combination rule may have any number of Start States (up to a

ma im m of 1 000 000)maximum of 1,000,000) The result of the combination is called a combined result Combination rules can be nested That means that the combined result of the combination i can be a start

state for the combinations i+1, i+2, …, n, and combined results of combination i+1 may be a start state for combinations i+2, i+3, …, n

...Q ψ γQ γG γG γ E Windk, Wind0, WindQ,Live k,Live Q,Dead k,Dead G,Gravity k,Gravity G,

55

Combination RuleCombined result Start State


56


Define the type of combination and the number of Start States Define the type of combination and the number of Start States— Before starting with calculations, you must define all the combination rules and

targets.

Combination name

Combination number

Combination name

Type of combinationNumber of Start States included in this combination rule

57

this combination rule


Maximum coefficient Minimum coefficient

If a default value is introduced, it will be applied to the rest of Start States.

58

applied to the rest of Start States.

Code Checking Results

.011637

.039639

.067641

.095642

.123644

.151646

.179647207649

PHASE 1:AXIAL +BENDING CHECKING

.207649

.235651

.263652

X

Y

Z

59

CivilFEM Creep and Shrinkage

Shrinkage Shrinkage— Time dependent deformation without external loads, due to the concrete

hardening. Creep Creep

— Time dependent deformation under the influence of stress

Can cause displacement and deformations that can affect the distribution Can cause displacement and deformations that can affect the distribution of stresses, the reaction forces and the pre-stressing forces that act on the structure.

60


)()()( ttt shcrelt (t, )o Strain due to creep only appears

after loading the structure

(t, ) CREEPoCRStrain due to shrinkageappears at the initial time

Elastic strain is produced, instantanously,at the moment the load is applied

(t)e

(t)SH

ELASTIC

SHRINKAGE

t,o t

2

F(t)

0

0

61

Strain components

t,o0


Assumption: Assumption: — Linearity: the creep deformation is proportional to the stresses

(t, )

(t,0)

(t, )1

CR

CR

CR

(0)CR

( )1CR

*

*

)( t (t, )2

1CR

CR

( )2CR*

),(·)(),(28,

0 tE

ttc

ccr

t, 1 2

Creep variation with time and with the load application age

The validity of this assumption is experimentally confirmed for initial stresses below 40% of the strength of concrete.

62


Assumption: (t, )CR

(t, )1CRI

(t, )2CRII

CR

(t, )CR

CR

Assumption:— Principle of superposition: the

deformation due to creep at time t caused by a stress

t, 1 2t,

t t

o o

yincrement applied at time is independent from any stress increment that takes place before or after time t,1 t,2

T I II

(t, )CR (t, )CR

before or after time

Therefore, the deformations due to creep are addable

1 t,

F FT I

CR CR CR

1 t,

CR CRT I

CR CRT I

CRII

due to creep are addable

t,1 2

o

o

t,1 2

o

Superposition principle

63

p p p p


64


Shrinkage in CivilFEM is computed from the shrinkage strain curves defined in the concrete material properties.

Curves are calculated from the available codes in CivilFEM— Curves are calculated from the available codes in CivilFEM— Curves can be defined by the user point-by-point.

Sh i k t i ill b t d i ll t i l ith th h i k Shrinkage strains will be computed in all materials with the shrinkage option activated.

— They are introduced in the model by temperature increments and calculated from the thermal strains and the thermal expansion coefficient of the materialfrom the thermal strains and the thermal expansion coefficient of the material.

— Since shrinkage strains are related to thermal strains, temperature increments must not be applied to elements that are associated to materials with the shrinkage option activated.with the shrinkage option activated.

65


For a correct evaluation of time-dependent properties ANSYS time For a correct evaluation of time-dependent properties, ANSYS time defined with command TIME, must coincide with active time of CivilFEMdefined with command ~ACTTIME.

All the structural elements of ANSYS support the modeling of concrete shrinkage with CivilFEM. Exceptions:

• All the PIPE elements• All the PIPE elements• SHELL91, SHELL181, SOLID191• SHELL99 and SOLID46 elements can only be used with KEYOPT(2) = 0 or 1

66


CivilFEM uses a standard step-by-step method to solve this integral: CivilFEM uses a standard step-by-step method to solve this integral:

I h b h d h i i di id d i i f i l I h— In the step by step method the time is divided into a series of intervals. In each intervals the equilibrium and compatibility conditions of the structure are satisfied. Strain is computed as follows:

t

cccrel d

Et

Ett

028,

)(·),()(

1)()(

— The solution procedure of CivilFEM employs a non linear calculation with automatic time discretization: the time steps, corresponding to ‘load steps’ and ‘substeps’, are chosen to follow the evolution of loads and model geometry.

k

ii

c

ik

ick t

Ett

tEt

1 28,

)(·),()(

1)(

67


Strain increments produced by creep are computed from the creep Strain increments produced by creep are computed from the creep coefficients defined in the material properties and from the stress increments produced during the steps of time discretization:

i

o

Variable action discretization

i t,o

Variable action discretization

)()(·),()()()( 11 kcr

k

iik

kcrkcrkcr ttttttt

68

)()()()()( 11 28,

1

kcri

ic

kcrkcrkcr E


These creep strains are introduced in the model using ANSYS Creep— These creep strains are introduced in the model using ANSYS Creep (subroutine UserCreep is programmed for this case, which uses an implicit time integration algorithm).

— It is also possible to take into account an aging coefficient. In this case creep strains are computed as follows:

k

ii

ikik

kkcr t

Ettttt

Ettt

11

1 )(·),(·),()(),()(

— t1 is the time of the application of the first load— If the value of the aging coefficient is not specified, the program uses:

i cc EE 1 28,28,

5.0

5.0

1),(

i

iik t

ttt

— Like in case of shrinkage, for a correct evaluation of time-dependent properties, ANSYS time defined with command TIME, must coincide with

ti ti f Ci ilFEM d fi d ith d ACTTIME

69

active time of CivilFEM defined with command ~ACTTIME.

CivilFEM Creep – Effective Modulus Method

This method consists using a elasticity modulus called effective modulus which— This method consists using a elasticity modulus called effective modulus which takes into account the additional strain caused by phenomenon of creep

— The effective modulus is calculated by the following expression:The effective modulus is calculated by the following expression:

,1

,.

tE

EtE

x

xeffcr

,28

1 tEx

— The concrete age at the moment of the load application is calculated as the difference between the load application time, TAppLoad and the material activation time, Tact.

TActTAppLoad

70

CivilFEM Creep – Effective Modulus Method

Thi i lifi d th d d l l d t f h ti t b This simplified method needs only one load step for each time to be solved, so this method is much faster than the step by step method.

Under this method, the creep strain only depends on the current state of stresses that’s why it’s independent of the previous load history. This method provides accurate results for concrete stresses almost constant in titime.

This method is based on the substitution of the material elasticity modulus by an effective modulus so it isn’t possible to determine the creep strain independent to the elastic strain so the final elastic strain will be the combination of these.

71


Element types that are supported in CivilFEM to model concrete creep: Element types that are supported in CivilFEM to model concrete creep: Step by step method:

— Beam: LINK180, BEAM188, BEAM189Sh ll SHELL181— Shell: SHELL181

— 2D Solid: PLANE182, PLANE183— 3D Solid: SOLID185, SOLID186, SOLID187

Eff ti d l th d Effective modules method:— All the ANSYS structural elements.

Element types that are supported in CivilFEM to model concrete Shrinkage:

— All the ANSYS structural elements except:• All pipe elements.• SHELL 91, SHELL 181, SOLID 191.• It can only be used on SHELL 99 and SOLID 46 elements if KEYOPT (2)=0 or 1.

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Creep and Shrinkage Time Stepping

~CFMP,1,LIB,CONCRETE,EC2,C16/20 ! ConcreteCFMP 1 CONCR KCREEP 1 ! C b St B St M th d~CFMP,1,CONCR,KCREEP,,1 ! Creep by Step By Step Method

~CFMP,1,CONCR,KEYCT,,0~CFMP,1,CONCR,KSHRINK,,1 ,0,0,0 ! by temperatures~CFMP,1,CONCR,AGESRINI,,10 ,0,0,0 ! concrete age when shrinkage

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!TIME,10 $ ~ACTTIME,10 ! 10 DaysRATE,ONNSUBST,1SOLVENSUBST 10NSUBST,10,TIME,15 $ ~ACTTIME,15 ! 15 DaysSOLVENSUBST,10,TIME,25 $ ~ACTTIME,25 ! 25 Days, $ , ySOLVETIME,90 $ ~ACTTIME,90 ! 90 DaysSOLVETIME,365 $ ~ACTTIME,365 ! 365 DaysSOLVETIME,1000 $ ~ACTTIME,1000 ! 1000 DaysSOLVETIME,10000 $ ~ACTTIME,10000 ! 10000 DaysSOLVE

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SOLVE

NON- INCREMENTAL ANALYSIS:

Construction Sequence (Curing) Analysis

S l

Concrete

The beam is built by phases, but the supports will not be taken out

Steel

INCREMENTAL S S

The beam is built by phases, but the supports will not be taken out until concrete has gained resistance.

ConcreteINCREMENTAL ANALYSIS:

Steel

Concrete

First the steel beam is placed and then the concrete, without resistance, will b d th t l t t

Steel

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be poured on the steel structure.

Cable Stayed Bridge Wizard

Nonlinear Construction Process Analysis: Nonlinear Construction Process Analysis:

YX

Y

XY

Z

XZ

XZ

MN

MX

XY

Z

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— ~CPDEF,1,3 ! 3 Phases— ! Phase 1

CPSTDEF 1 TIME 0Geometry

— ~CPSTDEF,1,TIME,0— ~CPSTDEF,1,SS,6,14,,0— ~CPSTDEF,1,SS,1,6— ~CPSTDEF,1,TENDON,1,10 Phases

40 m 40 m50 m

— ~CPSTDEF,1,TENDON,11,30,,0— ! Phase 2— ~CPSTDEF,2,TIME,12 ! 12 days— ~CPSTDEF,2,SS,1,11 Cross Sections

Li i i Li i i Li i i

50 m 30 m50 m

Phase 1 Phase 2 Phase 3

Section 1

— ~CPSTDEF,2,TENDON,1,20— ~CPSTDEF,2,TENDON,21,30,,0— ! Phase 3— ~CPSTDEF,3,TIME,24 ! 24 days 8 m 8 m12 m 12 m 8 m 8 m12 m 12 m10 m 10 m15 m 15 m

Section 2 Section 2 Section 2 Section 2Section 1

Linear transition

Section 1

Linear transition

Section 1

Linear transition

Section 2

, , , y— ~CPSTDEF,3,SS,1,14— ~CPSTDEF,3,TENDON,1,30

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Postprocess Results

-.161E+ 08-.985E+ 07-.361E+ 07.263E+ 07.887E+ 07.151E+ 08214E+ 08

PHASE 1:BENDING MOMENT MZ -.228E+ 08

-.152E+ 08756E+ 07

PHASE 2:BENDING MOMENT MZ

X

Y

Z

.401E+ 08

.214E+ 08

.276E+ 08

.338E+ 08-.756E+ 07.765E+ 07.152E+ 08.229E+ 08.305E+ 08.381E+ 08.457E+ 08

BENDING MOMENT MZ

X

Y

Z

-.220E+ 08-.143E+ 08-.665E+ 07.101E+ 07.867E+ 07.163E+ 08

PHASE 3:BENDING MOMENT MZ

X

Y

Z

.163E 08

.240E+ 08

.316E+ 08

.393E+ 08

.470E+ 08

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XZ

Case Study: Sil River Bridge

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