MIDAS SteelCompositeCurvedBridgeTutorial

7/30/2019 MIDAS SteelCompositeCurvedBridgeTutorial

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Bridgin g Your Innovat ions to Real i t ies

Curved Steel I-Girder Bridge


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Bridging Your Innovations to RealitiesBridging Your Innovations to Realitiesmidas Civil

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Overview

1. The bridge geometry is made.1. Materials and sections are defined.

2. Geometry is made from scratch.

3. Crossbeam/ diaphragm modeling.

4. Boundary conditions are applied.

5. Loading is applied. (Self weight and SIDL)

2. Live Loads are applied as per AASHTO LRFD.

1. Two lanes is defined.

2. The lane can carry vehicles in both directions.

3. Analysis

1. Response Spectrum2. Live load


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1. Introduction

32 ft

30 ft

200 ft

6 ft

1.5 ft

8 in


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1. Introduction

FEA Modeling of Steel Bri

dges

1. Beam Element (Composite Section)

2. Beam & Plate Elements

3. Plate Elements


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2. Materials

Propert ies> Material > Add

Steel:

1. Select Steel under type of design.

2. Select ASTM09(S) under SteelStandard.

3. Select A709-50W type from DB.

4. Click Apply.

Concrete:

5. Select Concrete under type of design.

6. Select ASTM(RC) under ConcreteStandard.

7. Select C5000 (for pier and pier table).

8. Click Apply.

Concrete for Crossbeam:

9. Select C5000 from DB, then Standardas None.

10. Enter Name as Crossbeams.

11. Set Weight density as Zero.

12. Click OK.

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3. Sections

Propert ies > Section > Add > selectDB/User tab

1. Select I-section

2. Select User

3. Plug in dimensions as provided

4. Click Change Offset

5. Select Center-Top

6. OK

7. OK

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Propert ies > Section > Add > DB/User

Diaphragm:

1. Select BD/User tab.

2. Select I-Section, and DB

3. Select AISC(US)under Steel Standard.

4. Enter name Diaphragm , as W16X45fromDB.

5. Change Offset to CenterTop.

6. Click Apply

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Sections

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Steel Composite Girder Ramp


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Propert ies> Section > A dd

Bracing:

1. SelectDB/User tab.

2. Select Angle Section, and DB.

3. Select AISC(US)under Steel Standard.

4. Enter name as Bracing, and L- 4X4X3/8from DB.

5. Set Offset as Center-Center.

6. ClickApply.

Pier :


8. Select Sol id Round.

9. Select User.

10. Enter name as Pier.

11. Enter Diameter as 72 in.

12. ClickApply.

Pier Cap Center:

13. Select Solid Rectangle.

14. Name as Pier Cap Center.

15. Enter H as 72and B as 72.

16. Set Offset as CenterTop.

17. Click OK.

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910

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3. Sections


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Properties > Section

Add Section

Pier Cap: (P_L)

1. SelectTaperedSection Tab.

2. Select Sol id Rectanglesection for the ends of Pier Cap.

3. Enter name as P_L for left end.

4. Enter values for i and j .

5. Apply y and z axis variation forl inear.

6. Set OffsetCenter Top.

7. ClickApply

Repeat above step s again for the other end of cap(P_R) (i and jend interchanged)

Dummy Crossbeams:


2.SelectSol id Rectangle

3. Enter name as Dummy Crossbeams.

4. SelectUser.

5. Enter the H as 8 and B as 60. (Note: Thickness of beam =deck thickness)

6. Set Offset as Center-Bottom.

7. Click OK.

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Define Tapered Section properties (For Pier Cap)

3. Sections

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Propert ies > Thickness

1. In-plane & Out-of-plane: 8 in

2. Check Plate offset

3. Value: 4 in

4. OK

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3. Sections

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4. Modeling

1. Node/Element > Nodes > Create nodes. Create nodes at (0,0,0) and copy once.

2. Create node at (100,30,0)

3. Select all by clicking and translate (Nodes>Translate) along Y axis to make the nodes for edge girders

1 2 3

4


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4. Modeling

1. Node/Element > Nodes > Rotate Nodes. Rotate nodes at abutment 1 (left side)by 30 first.

2. Then abutment 2 (right side) by - 30.

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4. Modeling

1. Node/E lemen t > E lemen ts > Create L ine Elements on Cu r ve. Create Line Elements on Curve by usingArc by 3 Points methods. Enter 40 for Number of Segments. Click in field P1 and then click on nodes from

left to right (like nodes 1, 2, 3)2. Repeat for the other four girders.

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4. Modeling

1. Select beam element of two exterior girders, be aware that only beams elements should be selected not

any nodes

2. Hit Delete key from your keyboard. The nodes should remain in place

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4. Modeling

1. Create diaphragms for Abutment 1. Click in nodal connectivity field and click on nodes 7,1,4.

2. Repeat step 1 for diaphragm over Pier Cap and Abutment 2.3. Repeat Step 1 for every 4th node (diaphragm at pier cap) on inner edge girder with section as Bracing as shown.

Abut. 1 Abut. 2

Over

Pier cap

Diaphragm Sections

Toggle off Hidden


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4. Modeling - End Diaphragm

1. Right click on Diaphragm section from Works Tree Menu and select Active. Then Select All and translate(Node/Element > Nodes>Translate) along Z axis by (0,0,-76.8), to make the nodes for Bottom chords of

diaphragms at abutments.

2. Node/Element > Elements Create Elements. Create bottom chords by connecting the translated nodes usingbracing sections.

Change units to inch


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3. Change element type to Truss and create inverted K- bracings for end diaphragms by snapping nodes at the midpoints of the bottom chord.*

4. Click in Nodal connectivity. Click node at top and then move down to the bottom chord, the cursor willautomatically be placed at its mid point, and click there.*

5. Repeat for all end-diaphragms. (i.e. at pier cap and abutment 2)

* 2 signifies that nodes will be snapped automatically to

divide the element into . It can be changed to 3,4,5,,,,, to

divide element by snapping nodes at 1/3 , ,1/5 ,.of

element length.

At bottom-right corner of midas CIVIL window

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6. Bound ary>Rigid Links. Create Rigid Link between top and bottom nodes

on the girder webs at Abutment 1 diaphragm; the bottom node asMaster node and top node as Slave node.

7. Click in Master node field and then click on bottom node in Model Viewwindow.

8. Use Select Single to select the node directly above Master node asSlave node.

9. Click on typical type as Rigid Body.

10 Click Apply.

11. Repeat for other girder webs at Abutment 1 diaphragm, and then forAbutment 2 diaphragm.

Rigid links

Cross Bracings

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Slave Node

Master Node

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4. Modeling - Intermediate Diaphragm

1. Activate All and right click on Bracing section from Works Tree Menu and select Active. Then Select by Window themember corresponding to intermediate diaphragm.

2. Click Activate(F2). Select All and Translate nodes (Node/Element > Nodes>Trans late) along Z axis by (0,0,-74.4) , tomake the nodes for the bottom chords of intermediate diaphragms.

3. Node/Element > Elements > Create Elements. Create bottom chords by connecting the translated nodes using bracingsections.

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4. Change element type to truss and check off intersect Node and Element and create cross bracings for

intermediate diaphragms.5. Click in Nodal Connectivity. Click node at top and then move down diagonally to the bottom chord.

6. Repeat for all intermediate diaphragms.

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Intermediate Diaphragm

Bottom ChordCross Bracing



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7. Bound ary > Rigid Links. Create Rigid Link between top and bottom nodeson the girder webs at intermediate diaphragms. The top node asMaster node and bottom node as Slave node.

8. Click in Master node field and then click on top node in Model View window.

9. Use Select Single to select the node directly below Master node asSlave node.

10. Click on typical type as Rigid Body.

11. Click Apply.

12. Repeat for other girder webs at intermediate diaphragm, and then for otherintermediate diaphragm.

Rigid links

Cross Bracings9

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Slave Node

Master Node

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Node/Element > Elements >Aut o Mesh

1. Select Nodes2. Type: Quadrilateral

3. Select Material 1

4. Select Thickness 1

5. Click the box to turn to green

6. Select nodes one by one in clockwise direction starting from left topnode to create an enclosed area (so the 1stnode and the last nodeshould be the same)

7. When all nodes selected > Click Apply

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4. Modeling Concrete Deck

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4. Modeling Concrete Deck

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4. Modeling - Pier

1

A

1. Activate All . Switch to Top-View Select by Window Select member corresponding to end diaphragm

over pier cap. (Box A)2. Click Activate(F2) and switch to Left-View

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4. Modeling

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Node AGirder bottom Nodes1

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1. Use Select Single and select the bottom nodes of the girders.

2. Translate by (0,0,-12.4). Node/Element > Nodes>Trans late

3. Select node A using select single, and translate through unequal distance along y axis by -36,-138,210,138.


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4. Modeling

1. Node/El emen t > El emen ts>Cr eat e El emen ts . Set material as C5000.

2. Create Pier Cap left end using Section as P_L ,click in nodal connectivity and click on nodes along a to c .3. Change Section to Pier Cap Center, click in nodal connectivity and then click nodes c to e.

4. Change Section to P_R , click in nodal connectivity and then click on nodes e to g.

a b c d f ge

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4. Modeling

1. Pr op er ties >Tap er ed S ec ti on G ro up .

2. Select by window the right end of pier cap.3. Enter name as P_Right .

4. Z-Axis variation as Polynomial (2) with Symmetric planefrom J end.

5. Y Axis variation being Linear.

6. Click Add.

7. Select by Window the left end of Pier Cap.

8. Name as P_Left and Z axis symmetric plane from I-end.

9. Click Add.

Left End Right End

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4. Modeling

1. No de/Elemen t > No des >Tr an slat e. Translate node a by (0,0,-72 in).

2. Using Select Single, select the translated node3. No de/Elemen t > Elemen ts >Ex tru de . Extrude Node into line element to create pier as shown in dialog box.

Node a

Newly Translated

node

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4. Modeling

1. Bound ary > Elastic Link.

2. Select Rigid Type.

3. Click in 2 Nodes field and then click at nodes a and b.

4. Check on Copy Elastic link and copy along Y axis as shown

5. Click on nodes c and d.

6. Click on d and e.

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6. Boundary Conditions: Supports

Model> Boundary> Supports

1. Select the support nodes.

2. SelectSupport type.

3. ClickApply.

Repeat for abutm ent nodes.

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Interior girder

node Exterior girder

node


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Load>Static L oad Cases

1. Enter SW, SIDL as Dead Loads.

7. Loads

Steel Composite Curved Bridge


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Load>Self Weight

1. Load case name as SWand group name asdefault.

2. Z = -1

3. ClickAdd.

SIDL:

4. . Select the elements to be loaded. For example,for Girders, double click on girder sectionfrom Works Tree.

5. Load>Element B eam Load. Load case name asSIDL .

6. Enter element beam loads as UDL in z direction.

-0.5 kips/ft (Change units from in to ft).

7. ClickApply.

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7. Loads: Self Weight and SIDL



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7. Loads: Structure Groups

1. Click on Groups tab under Tree menu.

2. Right click on Structure group and click on New

3. Enter name as Girder, clickadd.

4. Enter name as Crossbeams + Diaphragms, clickadd, clickclose.

5. Click on Select by Plane and select XY plane with Z=0ft. and clickClose.

6. ClickActivate.

7. Double click on Girderunder section in Works tree to select all girders.

8. Go to groups tab, click on Girderunder structure group and drag anddrop it over the Model View window. (to assign the girder membersto the structure group.)

9. Right click on Girderstructure group and selectInactive.

10. Click on Select All and drag and drop the Crossbeam +Diaphragmstructure group on Model View window to assign thediaphragms and crosbeams to the structure group.


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7. Loads:Live Loads (Define Lane)


Load > Moving >Moving Load Code.

1. SelectAASHTO LRFDfrom the moving load code.

Load > Moving Load An alysis > Traff ic Surface Lanes.

1. Lane Name : Lane 1

2. Lane width: 12 ft

3. Wheel spacing:6ft

4. Offset: -7 ft

5. Selection by: Picking.

6. Select all exterior nodes in bottom one by one starting from left bottom corner.

7. Apply

8. Repeat the process for Lane 2. Only change Eccentricity to -23 ft

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id i il


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Load > Moving Lo ad Analysis Data> Moving

Load case.

5. Enter a Load case name: MVL

6. Check or modifyMult ip le Presence Factor.

7.Select loading effect for sub load case asIndependent .

8. Add Sub-Load case.

9. Select one of the vehicles..

10. Scale factor as 1, and min. number of loadedlane as 1and max. as 2.

11. Select lanes L1 and L2.

12. ClickOK .

13. Similarly create load case for HL-93 TandemVehicle.

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Load > Moving Lo ad Analysis Data>

Vehicles.

1. Click Add Standard

2. Click on Vehicle load type

3. SelectHL-93 TRKas first vehicle loadtype., DLA = 33%,Click Apply

4. SelectHL-93 TDMas second vehicleload type. Click OK

7. Loads:Live loads (Vehicles and Load cases)

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id Ci il


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7. Loads: Moving Load analysis Control

Analysis> Moving Load An alysis Control Data

1. Set the analysis control as specified in the dialog box.1

id Ci il l i d id


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Load > Static Loads > Masses > Loads to m asses.

1. Select the Mass direction :X,Y,Z

2. Load type: Nodal, Beam, Floor, Pressu re

3. Select the Load case (SIDL) to be converted and scale factor.

4. ClickAdd.

5. ClickOK.

Model> Structure type

6. Check on Convert Self Weight into Masses.

7. Loads: Conversion of Loads to masses for seismic analysis.

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id i Y I i li iid i Y I i li iid Ci il S l C i C d B id


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8. Response Spectrum Analysis

Load> Response Spectrum analysis data > Respons e spectrum func tions

1. Enter the Function Name.

2. Import the response spectrum coordinates as obtained from RS.spdfile, [AASHTO LRFD , Soil type E site.].

3. Response spectrum is generated simultaneously.

4. Enter the Damping Value and acceleration due to gravity.

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7. Seismic Load case / Eigenvalue Analysis Control

Load> Response Spectrum analysis data > Respons e spectrum load cases

1. Enter the Load casename. RS-X

2. SelectDirectionandExcitat ion angleas 0 deg.

3. SelectFunction name.

4. ClickAdd.And repeat with Load c ase name as RS-YandExcitat ion angleas 90 deg

5. ClickEigenvalue Analysis Control .

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6.SelectLancoz Vectorsas type of Analysis.

7. Enter no. of frequencies as 10.

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9. Perform analysis

Analysis> Perform Analysis


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Bridgin g Your Innovat ions to Real i t ies

MIDAS SteelCompositeCurvedBridgeTutorial

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