135640720 FB MultiPier Help Manual

Table of Contents

FB MultiPier

17

What’s New in FB-MultiPier?

17

Program Menus

19

Model Data 21

New Project/Problem Tab ... 21

General Pier Option... 23

Pile and Cap Option ... 23

Single Pile Option ... 24

High Mast Light/Sign Option... 25

Retaining Wall Option... 26

Sound Wall Option... 27

Stiffness Option ... 28

Pile Bent Option... 29

Column Analysis Option ... 30

Bridge (Multiple Piers) Option ... 31

Analysis Tab... 32 Analysis Tab ... 32 Pile/Pier Behavior ... 34 Cap Behavior ... 34 Section Properties ... 35 Soil Behavior ... 35 Iteration Control ... 35

Interaction Diagram Phi Factor... 36

Analysis Type ... 36

Design Options ... 37

Print Control... 37

AASHTO Tab ... 38

AASHTO Tab... 38

AASHTO Load Factors Table... 39

Automated AASHTO Loads... 40

AASHTO Load Manager... 41

Wind Load Generator ... 42

AASHTO Load Combination Preview Table... 43

Limit States to Check... 44

Dynamics Tab ... 45

Dynamics Tab... 45

Analysis Type Dynamic ... 47

Edit Load Functions... 49

Load Function Edit Table... 51

Pushover Tab... 52

Pushover Tab ... 52

Pier Data Edit... 53

Pile and Cap Tab ... 53

Pile and Cap Tab... 53

Pile Length Data ... 54

Pile Cross Section Type ... 55

Pile/Shaft Type ... 56

Pile to Cap Connection... 56

Pile Cap Data ... 57

Pile Cap Grid Geometry ... 57

Grid Spacing Table... 58

Edit Cross Section ... 59

Gross Section Pile Properties ...59

Gross Pile Properties ...59

Pile/Shaft Segment List...60

Pile Set Info...61

Database Section Selection ...61

Section Type ...62

Segment Dimensions ...63

Section Properties...63

Full Cross Section Pile Properties...64

Full Cross-Section Pile Properties...64

Detailed Cross Section...65

Section Dimensions ...66

Section Type ...67

Section Type ...67

Circular Section Properties ...67

Circular Section Properties...67

Edit Bar Groups...69

Group Data...70

Confined Concrete Option...71

Shear Reinforcement ...73

Miscellaneous ...73

Confined Concrete Model ...73

Mander Models for Confined Concrete...74

Unconfined Concrete ...82

Reinforcement... 83

Longitudinal Reinforcement...84

Transverse Reinforcement... 87

Steel Jacket... 87

Full-Scale Column without Steel Casing... 88

Half Scale Column With Steel Retrofitting Jacket... 90

Conclusions... 91

Rectangular Section Properties ...92

Rectangular Section Properties...92

Void Data ...94 H-Pile Properties ...95 H-Pile Properties ...95 Section Dimensions ...95 Section Orientation...96 H-Pile Properties ...96

Pipe Pile Properties...96

Pipe Pile Properties...96

Material Properties ...96

Material Properties ...96

Section Stress-Strain Plot ...98

Soil Tab ... 99

Soil Tab... 99

Soil Layer Data ... 101

Elevations ... 102

Soil Table... 102

Soil Layer Models ... 104

Soil Layer Models...104

Soil Dynamics Dialog ...108

Soil Model Plot ...108

Printable Soil Graph ...110

Advanced Soil Data...112

Soil Strength Criteria ... 113

Soil Strength Criteria ...113

SPT Window ...114 Pier Tab... 115 Pier Tab ... 115 Taper Data... 116 Pier Geometry ... 117 Pier Geometry...117

Pier Rotation Angle ...119

Bearing Locations ...120

Bearing Angle ...121

Pier Cross Section Type... 122

Pier Cross Section Type ...122

Gross Section Pier Properties...122

Gross Pier Component Properties ...122

Pier Components ...123

Database Section Selection ...124

Section Data...125

Section Properties...126

Parabolic Taper Cantilever Properties ...126

Full Cross Section Pier Properties ...127

Full Pier Component Properties ...127

Section Dimensions ...128

Section Type ...130

Section Type ...130

Circular Section Properties ...130

H-Pile Properties ...130

Rectangular Section Properties ...130

H-Pile Properties ...130

H-Pile Properties ...130

Bullet Section Properties...130

Bullet Section Properties ...130

Group Data...131

Void Data ...132

Cross Section Orientation ...132

Material Properties ...133

Bent Cap ... 133

2D Bridge View ... 133

Wall Structure... 133

Sound Wall Explanation ... 133

Extra Members Tab... 134

Load Case ... 139

Buoyancy ... 140

Node Applied ... 140

Loads ... 140

Bearing Location Loads ... 141

Load Table... 142

Load Table ...142

Dynamic Loads ...142

Table Format...144

Table Edit Options...144

Load Case Options ...144

AASHTO Load Table... 145

AASHTO Load Table ...145

AASHTO Table Format ...146

AASHTO Table Edit Options...146

AASHTO Load Case Options...147

Spring Tab... 147

Spring Tab ... 147

Spring Stiffness ... 148

Spring Nodes ... 148

Discrete Mass/Damper Tab ... 149

Mass/Damper Tab ... 149

Mass/Dampers in 3D View ... 149

Retaining Tab... 151

Retaining Tab ... 151

Soil Layer... 152

Wall and Layer Geometry... 152

Retaining Wall Explanation... 153

Soil Layer Data ... 154

Soil Layer Data ...154

Retaining Wall Soil Layer Data ...155

Wall Load Data ... 155

Wall Load Data ...155

Surcharge ...155

Bridge Data Edit ... 156

Bridge Tab... 156

Bridge Tab ... 156

Edit Supports ... 158

Edit Custom Bearings... 159

Edit Span ... 160

Add Substructure... 163

Span End Condition... 164

Model View Windows

165

Soil Edit Window ... 165

Pile Edit Window... 166

Pile Edit Window ... 166

Zoom Feature Tutorial ... 168

Pile Data... 168

Edit Cap Thickness ... 169

Custom Grid Spacing ... 169

Bridge Plan View Window ... 170

3D View Window ... 170

3D View Window ... 170

Program Results

174

Pile Results... 174

Pile Results ... 174

Pile Selection ... 174

Plot Display Control... 175

Graphs ... 176

Printable Forces Dialog... 177

Pier Results ... 179

Pier Results... 179

Pier Selection ... 179

Graphs ... 180

Printable Forces Dialog... 180

Pier Cross Section Table ... 182

Pile Interaction ... 185

Interaction Diagrams ... 185

Pile Selection ... 185

Pile Segment Selection ... 186

Pile Element Selection ... 187

Interaction Diagram... 188

Pier Interaction ... 189

Pier Selection ... 189

Pier Segment Selection ... 190

Pier Element Selection... 191

3D Results ... 192

3D Results... 192

3D Results Window... 193

3D Results Dynamic Options ... 196

Result Forces Dialog... 197

3D Display Control ... 198

3D Display Control... 198

Display Control ... 200

Node Information ... 202

Max Min Forces Dialog... 202

XML Report Generator ... 203

XML Report Generator... 203

Results Viewer... 205

Results Viewer ... 205

General Modeling

206

Taper Modeling... 207

Bridge Span Overview... 210

Node Numbering ... 213

Span Length Calculation ... 214

Preliminary Soil Values... 216

Bridge Span Modeling

216

Transfer Beam Properties ... 219

Setup Options

235

Expanding Memory... 235

The FB-MultiPier Engine can be adjusted to allow larger pile system solutions. If the problem is to large for the current settings the engine will generate a error message like: ... 235

Not enough Memory... 235

You can correct this from the Program Settings Dialog in the control menu in the interface as mentioned above. ... 235

Program Settings ... 235

FB-Pier License Installation

236

FB-MultiPier operates using a license file to determine its status. All shipped versions run in Demo mode as the default. The program can be "unlocked" into various modes including full version and student version, networked or stand-alone. This unlocking can be done by hand, through phone contact with the Bridge Software Institute ( http://bsi-web.ce.ufl.edu ) or automatically through an internet connection to the BSI web server... 237

The program requires a license file to be installed. This license file is linked to the computer on which it is installed. ... 237

The following describes the modes and processes required:... 237

E-mail/Fax/Phone License Update ... 238

FB-MultiPier License Installation Help... 239

Update a License on a Stand Alone Workstation... 240

Update/Install a License on a Network Server ... 241

License Update Tutorial ... 242

Set Client Path for a License File on a Network Server ... 242

Transfer License to a Different Computer ... 244

Toolbar Icons

246

General Pier Wizard ... 248

Batch Analysis

249

Running FBPier_eng in Batch Mode ... 250

Soil-Pile Interaction

251

Soil Resistance Due to Pile Rotation... 255

This option is used for the program to calculate and apply rotational springs to the pile nodes in the ground. These springs are based on the axial resistance of the piles (skin friction) as well as the rotation of the piles. It is particularly important in soil layers where the piles can develop large values of skin friction. ...256

Calculation of bending strains ...256

Soil’s Lateral Resistance P(F/L) Form Bending Moments and Skin Friction ... 256

Moment Due to Side Shear, Ms ... 257

Soil Properties ... 258

Lateral Soil-Pile Interaction... 265

Figure B17: Reese et al (1975) Static P-Y Curve for Stiff Clay Located Below the Water Table .274 P-Y Resistance for Florida Limestone (McVay) ... 275

Limestone (McVay no 2 - 3 Rotation) ... 277

Sand (API)... 280

Axial Soil-Pile Interaction ... 281

Driven Pile Sand (API) ... 282

Driven Pile Clay (API) ... 282

Axial T-Z Curve for Side Friction... 283

Axial Skin Friction for Florida Limestone (McVay)... 284

Drilled and Cast Insitu Piles/Shafts ... 288

Axial T-Z(Q-Z) Curve for Tip Resistance ... 293

Driven Pile Sand (API)_QZ... 295

Driven Pile Clay (API)_QZ... 295

Drilled and Cast Insitu Piles/Shafts ... 296

Torsional Soil-Pile Interaction... 301

Finite Element Theory

303

Membrane Element ... 304

Plate Element ... 304

Flat Shell Elements... 306

Mindlin Theory ... 307

Special Element for FB-MultiPier... 309

Mesh Correctness and Convergence ... 310

The difference in element stresses at a node is an important measure of model correctness. In general, we do not have the exact displacements in order to check our model. Hence, the stress check is necessary to verify convergence of our model. If the difference in stresses between elements is small the finite element mesh is good. ... 311

Nonlinear Behavior

311

Discrete Element Model ... 311

Discrete Element Model ... 311

Discrete element model is elaborated in the following sections (use the links): ...312

Element Deformation Relations ... 312

Integration of Stresses ... 314

Element End Forces... 317

Element Stiffness ... 317

Stress-Strain Curves ... 319

Stress-Strain Curves ... 319

Concrete... 319

Mild Steel ... 320

High Strength Prestressing Steels ... 321

Adjustment for Prestressing... 322

When piles are prestressed prior to installation, there are stresses and strains existing at the time of installation cue to the prestressing. The program shifts the origin of the stress-strain curve for the steel by the amount of the prestressing stress in the steel and the corresponding steel strain. Also, the program shifts the origin of the concrete stress-strain curve by the amount of compression in the concrete and the corresponding concrete strain. It is assumed that the prestressing is symmetrically placed and thus only a constant compressive stress is developed in the concrete due to the prestressing. ...322

Confined Concrete Model... 322

Bi-axial Interaction diagram ... 322

Equivalent Stiffness Formulation

329

Equivalent Stiffness Generation ... 329

Converting FB-MultiPier Coordinates to a Standard Coordinate System ... 331

Engine Input Users Guide

335

Global Headers... 335

Header ... 335

Print Control ... 336

General Control... 337

Multiple Pier Substructure Information... 340

Superstructure Information ... 342

User Defined Bearing Connection ... 346

Self Weight and Buoyancy Load Factors... 348

Bridge Spring Toggle ... 348

Case #1...348 Case #2...348 Case #3...348 Case #n...348 Pushover ... 349 Combination (AASHTO)... 349 COMBINATION ... 350

Modify Load Factors... 351

Dynamic Control Parameters... 353

Dynamic Step by Step Integration ... 356

T1,F1 T2,F2 T3,F3 T4,F4...357

Spectrum Analysis ... 357

Span Concentrated Nodal Loads... 360

Pier Specific Headers ... 362

Pile Information ... 362

For Nonlinear Analysis of Oblong Piers, used with NLOPT=2 and KTYPE=4 NOTE: This type is ONLY available for pier elements NOT for piles. ...379

Multiple Pile Sets... 386

PILESET ... 386

PILESET ... 386

Pile Batter Information ... 387

Missing Pile Data ... 388

Multiple Soil Sets... 397

SOILSET... 398 SOILSET... 398 Structural Information... 398 SOUND... 402 STRUCTURE ... 417 Column Information... 418

Concentrated Nodal Loads ... 419

Wind Load Generation ... 422

Spring Properties ... 425

Pile Cap Properties ... 427

Removed Pile Cap Element... 427

Removed Pier Cap Element ... 428

Bearing Connection... 429 Point Mass ... 430 MASS...430 NS,NF,NI M=MX,MY,MZ,MRX,MRY,MRZ ...430 Point Dampers ... 431 DAMP...431

NS,NF,NI C=MX,MY,MZ,MRX,MRY,MRZ...431

Dynamic Load Function Application... 432

NF,NL,NI L=LCN F=L1,L2,L3,L4,L5,L6 M= MODEXF D=FUNC ...432

Post Processing Formats

433

Multiple Pier Generation ... 433

Pier to Superstructure Connectivity... 434

Geometry and Control Information ... 437

Npset ... 437

Is the number of pile sets for the piles. ... 437

Nseg1, nseg2, nseg3, ….. nsegN ... 437

Name... 438

NUMNP, nstr, kbent ... 438

X, Y, Z ... 439

Idx, idy, idz, idrx, idry, idrz... 439

Mtype, nume... 440

DX, DY, DZ, RX, RY, RZ ... 440

MINIMUMS... 441

Pile Data ... 442

NUMPN, NUMLC ... 443

NPX, NPY, nmpil, npil, kfix, nplnod... 443

TPL, GSE ... 444

Axial Forces for Beam Elements ... 445

Mtype, nume... 445

Axial ... 446

Maximum Moments in Beam Elements ... 446

Mtype, nume... 446

Rmom ... 446

Stresses of Pile Cap ... 447

Capacity Information... 447

Nxpile, nxstruc... 447

PTUV, YPC, ZPC ...448

Shear and Moment Results ... 449

W, V2I, V3I, V2J, V3J, XMI2, XMI3, XMJ2, XMJ3, XMMAX, XML, FRATI, FRATJ, AXLI, AXLJ... 450

Analysis Convergence Information... 450

Mode Shape and Frequency Information (Response Spectrum Analysis) . 452 AASHTO Load Combination Results ... 454

References 455

Tutorials

458

Segment Selection

460

Confined Concrete Model References

460

AASHTO Table

463

AASHTO Table

464

P-Y Multiplier Reduction for Shaft with Torsion

464

Barge Impact

466

BARGE ... 466

3D Bridge View

467

Calculating Foundation Stiffness Using FB-MultiPier

468

Sound_Wall_Eplanation

470

3D 3D Results ... 470

3D Display Control... 470

3D Node Information ... 471

3D Results Dynamic Options ... 471

3D Results Window... 471

AASH AASHTO Load Factors Table... 471

AASH Automated AASHTO Loads... 471

AASH Limit States to Check... 472

AASHTO Load Case Options...472

AASHTO Load Combination Preview Table... 472

AASHTO Load Combination Results ... 472

AASHTO Load Manager... 472

AASHTO Load Table ...473

AASHTO Table Edit Options...473

AASHTO Table Format ...473

Add Substructure... 473

Adjustment for Prestressing... 473

Analysis Convergence Information... 473

Analysis Type ... 474

Angle of Internal Friction ... 474

AP 1020 Pile Pier Behavior ... 474

AP 1033 Iteration Control ... 474

AP 1123 Print Control... 474

AP 1211 Soil Behavior... 475

AP 1258 Design Options ... 475

AP 1708 Interaction Diagram Phi Factor... 475

Axial Forces for Beam Elements ... 475

Axial Skin Friction for Florida Limestone ... 475

Axial Soil Pile Interaction ... 476

Axial T Z Curve for Side Friction ... 476

Axial T Z Q Z Curve for Tip Resistance... 476

Batch Mode... 476

Bearing Connection... 476

Bearing Location Loads ... 477

Bearing Pad Properties ... 477

Bridge Multiple Piers Option ... 477

Bridge Span Overview... 477

Bridge Spring Toggle ... 478

Bridge Tab ... 478

Cap Behavior ... 478

CAP Edit Cap Thickness... 478

Capacity Information... 478

CD Custom Stress Strain ...479

Clay API ... 479

ClayEnd ...479

ClaySide...479

Column Connection to the Pile Cap ... 479

Column Information... 479

Combination AASHTO ... 480

Concentrated Nodal Loads ... 480

Conclusions... 480

Concrete... 480

CONFINED CONCRETE MODEL...480

Control Menu ... 481

Converting FB Pier Coordinates to a Standard Coordinate System ... 481

Deck Modeling ... 481

DESCRIPTION OF TOOLBAR ICONS ... 481

Discrete Element Model ... 481

DrilledEnd ...482

DrilledSide...482

Driven Pile Clay API... 482

Driven Pile Clay API QZ ... 482

Driven Pile Sand API... 482

Driven Pile Sand API QZ ... 483

DrivenEnd ... 483

DrivenSide ... 483

Dynamic Control Parameters... 483

Dynamic Load Function Application... 483

Dynamic Step by Step Integration ... 483

Dynamics Tab... 484

Edit Custom Bearings... 484

Edit Load Functions... 484

Edit Span ... 484

Edit Supports ... 484

Element Deformation Relations ... 485

Element Dialog... 485

Element End Forces... 485

Element Stiffness ... 485

Engine Input Overview ... 485

Equivalent Stiffness Generation ... 486

Expanding Memory... 486

Failure Ratio for Cross Sections ... 486

FB PIER LICENSE INSTALLATION HELP ... 486

FB Pier1

486

General Control... 488

General Pier Wizard ... 488

Generalized Stress and Strain... 488

Geometry and Control Information ... 488

GRID 2094 Grid Spacing Table... 489

GRID Custom Grid Spacing... 489

Gross Pier Component Properties ...489

Gross Pile Properties ...489

Group Interaction ... 489

Half Scale Column With Steel Retrofitting Jacket... 490

Header ... 490

Help Menu ... 490

High Strength Prestressing Steels ... 490

HP H Pile Properties ...490 HP Section Dimensions...491 HP Section Orientation...491 Hyperbolic Curve... 491 ID Interaction Diagram ... 491 ID Interaction Diagrams ... 491 ID Pier Selection ... 491 ID Pile Selection... 492 Integration of Stresses ... 492 INTERACTION DIAGRAMS ... 492 Intermediate GeomaterialQZ...492 Intermediate GeomaterialTZ ...492

Lateral Soil Pile Interaction ... 493

LE Database Section Selection...493

LE Parabolic Taper Cantilever Properties ...493

LE Pier Components ...493

LE Section Data ...493

LE Section Properties ...494

License File... 494

Limestone McVay use 2 3 Rotation ... 494

Load Function Edit Table... 494

LOAD Load Case Options...494

LOAD Load Table ...494

LOAD Table Edit Options...495

LOAD Table Format ...495

Longitudinal Reinforcement...495

LP Database Section Selection...495

LP Full Cross Section Pile Properties ...495

LP Load Case ... 496

LP Loads... 496

LP Node Applied... 496

LP Pile Set Info ...496

LP Pile Shaft Segment List ...496

LP Section Properties ...496

LP Section Type...497

LP Segment Dimensions...497

Mander Models for Confined Concrete...497

Mass Damper Tab ... 497

Mass Dampers in 3D View ... 497

Matlock s Soft Clay Below Water Table... 498

Max Min Forces Dialog... 498

Maximum Moments in Beam Elements ... 498

MEM Extra Member Sections... 498

MEM Extra Members List ... 498

Membrane Element ... 499

Mesh Correctness and Convergence ... 499

Mild Steel ... 499

Mindlin Theory ... 499

Missing Pile Data ... 500

MLE Section Type...500

Mode Shape and Frequency Information Response Spectrum Analysisi ... 500

Modify Load Factors... 500

Multiple Pier Generation ... 500

Multiple Pier Substructure Information... 501

Multiple Pile Sets... 501

Multiple Soil Sets... 501

NLE Full Pier Component Properties ...501

NLE Section Dimensions ...501

NLP Material Properties ...501

NLP Section Dimensions ...502

NLP Section Type ...502

NONLINEAR BEHAVIOR ... 502

Nonlinear Solution Strategies ... 502

O Neill s Clay ... 502

O Neill s Sand ... 503

OP Bullet Section Properties...503

OP Cross Section Orientation ...503

OP Group Data ...503

OP Void Data ...503

P Y Resistance for Florida Limestone... 504

PAD Bearing Locations ...504

PI Pile Data ... 504

Pier Cross Section Table ... 504

Pier Element Selection... 504

Pier Rotation Angle ...504

Pier Segment Selection ... 505

Pier to Superstructure Connectivity... 505

Pile Batter Information ... 505

Pile Cap Properties ... 505

Pile Data ... 505

Pile Element Selection ... 506

Pile Information ... 506

Pile Segment Selection ... 506

Pipe Pile Properties...506

Plate Element ... 506

Point Dampers ... 507

Point Mass ... 507

Poisson s Ratio ... 507

POST PROCESSING FILE FORMATS ... 507

PP 1044 Pile Cap Grid Geometry ... 507

PP 1087 Pile Cross Section Type ... 508

PP Pile Cap Data... 508

PP Pile Length Data ... 508

PP Pile Shaft Type ... 508

PP Pile to Cap Connection ... 508

Printable Soil Graph ...510

Program Settings ... 510

PRP 1049 General Pier Option ... 510

PRP 1050 High Mast Light Sign Option ... 510

PRP 1051 Retaining Wall Option ... 510

PRP 1052 Sound Wall Option ... 511

PRP 1059 Pile and Cap Option ... 511

PRP 1060 Single Pile Option... 511

PRP 1061 Stiffness Option... 511

PRP 1062 Column Analysis Option... 511

PRP 1063 Pile Bent Option ... 511

PRR Graphs... 512

PRR Pier Results ... 512

PRR Pier Selection ... 512

PRR Printable Forces Dialog ... 512

Pushover ... 512

PYM Advanced Soil Data...513

Reese and Welch s Stiff Clay Above Water Table ... 513

Reese s Stiff Clay Below Water Table ... 513

References ... 513

Reinforcement... 513

Removed Pier Cap Element ... 514

Removed Pile Cap Element... 514

Result Forces Dialog... 514

Results Viewer ... 514

RET Retaining Wall Soil Layer Data ...514

RET Soil Layer ... 514

RET Soil Layer Data ...515

RET Surcharge ...515

RET Wall and Layer Geometry ... 515

RET Wall Load Data ...515

Retaining Wall Explanation... 515

Rigid Link Properties ... 516

RP Circular Section Properties...516

RP Confined Concrete Option...516

RP Edit Bar Groups...516

RP Group Data...516

RP Miscellaneous ...516

RP Shear Reinforcement ...517

Running FBPier eng in Batch Mode ... 517

Sand API ... 517

Sand of Reese Cox and Koop ... 517

SandEnd ...517

SandSide ...518

SECTION Detailed Cross Section...518

Section Properties ... 518

Self Weight and Buoyancy Load Factors... 518

Set Path for a License File on a Network Server ... 518

Shear and Moment Results ... 519

Shear Modulus ... 519

Soil Dynamics Dialog ...519

Soil Information ... 519

SOIL PILE INTERACTION ... 519

Soil Properties... 520

Soil Resistance Due to Pile Rotation... 520

Soil Table... 520

SP Elevations ... 520

SP Rectangular Section Properties...521

SP Soil Layer Data ... 521

SP Soil Layer Models...521

SP Soil Strength Criteria ...521

SP Void Data...521

Span Concentrated Nodal Loads... 522

Span End Condition... 522

Special Element for FB-PIER ... 522

Spectrum Analysis ... 522

SPR Spring Nodes ... 522

SPR Spring Stiffness ... 523

Spring Properties ... 523

SPT Window ...523

SS Default Stress Strain Curves ...523

SSPLOT Section Stress Strain Plot ...523

Steel Jacket... 523

STP Cross Section Type...524

STP Pier Geometry ...524

STP Taper Data... 524

Stress Strain Curves ... 524

Stresses of Pile Cap ... 524

Structural Information... 525

Subgrade Modulus ... 525

Superstructure Information ... 525

TAB 130 Soil Tab ... 525

TAB 132 Pile and Cap Tab... 525

TAB 134 Pier Tab ... 526

TAB 135 Load Tab ... 526

TAB 136 Analysis Tab ... 526

TAB 137 Problem Tab ... 526

TAB 243 Spring Tab ... 526

TAB 282 X Members Tab ... 526

TAB 285 AASHTO Tab... 527

TAB 290 Retaining Tab ... 527

TAB 298 Pushover Tab ... 527

Taper Modeling... 527

Torsional Soil Pile Interaction ... 527

Transfer Beam Properties ... 528

Transfer License to a Different Computer ... 528

Transverse Reinforcement... 528

Tutorials ... 528

Unconfined Concrete ...528

Undrained Strength ... 529

Update a License on a Network Server... 529

Update a License on a Stand Alone Workstation... 529

User Defined Bearing Connection ... 529

User DefinedPY ... 529

User DefinedQZ... 530

User DefinedTq ... 530

User DefinedTZ ... 530

WIN Soil Edit Window ... 531

Wind Load Generation ... 531

Wind Load Generation Table... 531

Wizard Menu... 532

XML Report Generator... 532

FB MultiPier

What’s New in FB-MultiPier?

FB-MultiPier is the newest development of the FB-Pier program. FB-MultiPier is based on the proven accuracy and reliability of FB-Pier with changes to the interface and features that make it even more powerful. The name has changed to reflect the new capabilities and to keep the two product lines separate.

Multiple Pier Modeling

Unique piers

Each pier can have an entire different set of properties, including: pier geometry, pile group size, soil strata, loads, etc. Each pier can also have its own elevation. Up to 99 piers can be easily generated to rapidly layout an entire bridge. The 2D Bridge window shows the bridge layout in plan and the 3D Bridge window shows the 3D visualization of the bridge.

Pier rotation

Each pier can have a rotation about the vertical (z) axis. This is ideal for modeling skew bridges and radial piers on curved alignments.

Bridge superstructure

The bridge superstructure is incorporated into the model using an equivalent beam that connects the centerline of two piers. The bearing connections at the pier supports can be released, constrained, or user-defined using a custom load-displacement curve.

Wind Load Generation

Wind loads can be applied to the entire bridge at once. The resulting loads are transferred to the bearings at each pier.

Dynamic Pier Analysis – Special Release Available

Time step integration

Time history load functions and ground acceleration records can be applied to the model. Different time step integration methods are available as well as a variety of analysis control parameters. Concentrated masses and dampers can be added to the model to simulate added mass and energy dissipation effects.

Modal analysis

The modal analysis option performs a frequency analysis of the model. Both frequencies and mode shapes are provided as output results.

Dynamic soil modeling

Soil gap modeling is available to model energy dissipation due to hysteretic damping. Cyclic degradation parameters are also available to modify the lateral soil response during dynamic loading.

Animated results

The 3D model displacement results can be animated for a time step integration analysis. Animation results can be played and paused and a slider bar is provided for selectively viewing individual time step results.

Time-Displacement plots

The displacement results for any model node can be plotted over time.

Seismic database

Program Menus

File Menu

The File menu handles the problem creation, file access, printing, and exiting the program.

Create a new problem Open an existing problem Close current problem Save current problem Prints the active window Access the printer setup

Previously openedfiles

Exit the program

Figure A7: File Menu Options

View Menu

The View menu controls the appearance of the toolbar at the top of the screen and the status bar at the bottom of the screen.

Show/hide toolbar Show/hide status bar

Show/hide 3D control (zoom) bar Figure A8: View Menu Options

Control Menu

The Control menu allows the user to access the output data from the program, log file options, program settings, access to the license update wizard, and control the appearance of the fonts used in the dialogs, graphics, and plots.

Figure A9: Control Menu Options

The Program Settings option will open the Program Settings Dialog with options for pile nodes, water tables and memory settings.

Wizard Menu

The Wizard menu provides access to General Pier Wizard. Following the steps provided by the wizard the user can quickly create a customized general pier model.

Figure A11: Wizard Menu Options

Help Menu

The Help menu provides access to the online help manual. The Help About option is provided to list the version number of the program and current system settings.

Figure A10: Help Menu Options

Help About Tutorial

Model Data

Global Data Edit

New Project/Problem Tab

New Project/Problem Tab

Figure A13: New Problem Tab

Change an existing one in the "Model Data" window.

Choose from the following problem types to view a picture of each standard type (default problems):

1. General Pier Option 2. Pile and Cap Option 3. Single Pile Option

4. High Mast Light/Sign Option 5. Retaining Wall Option 6. Sound Wall Option 7. Stiffness Option 8. Pile Bent Option 9. Column Analysis Option 10. Bridge (Multiple Piers) Option

General Pier Option

Figure A14: General Pier Model

Select this option to begin a typical pier problem.

For complete a list of problem options go to the Problem Tab page.

Figure A15: Pile and Cap Model

Select this option to begin a typical pile and cap problem.

For complete a list of problem options go to the Problem Tab page.

Figure A16: Single Pile Model

Select this option to begin a typical pile problem.

For complete a list of problem options go to the Problem Tab page.

Figure A17: High Mast, Light/Sign Model

Select this option to begin a typical high mast light/sign problem.

For complete a list of problem options go to the Problem Tab page.

Figure A18: Retaining Wall Model

Select this option to begin a typical retaining wall problem.

Note: With this option, the Pier page becomes the Wall Structure page.

Figure A19: Sound Wall Model

Select this option to begin a typical sound wall problem.

Note: With this option, the Pier page becomes the Wall Structure page.

For complete a list of problem options go to the Problem Tab page.

Figure A20: Stiffness Model

Select this option to begin a typical stiffness problem.

For complete a list of problem options go to the Problem Tab page.

Figure A21: Pile Bent Model

Select this option to begin a typical pile bent problem.

Note: With this option, the Pier page becomes the Bent Cap page.

For complete a list of problem options go to the Problem Tab page.

Figure A22: Column Model

Select this option to begin a typical column problem.

For complete a list of problem options go to the Problem Tab page.

Figure A23: Bridge Model

Select this option to begin a typical bridge (multiple piers) problem.

For complete a list of problem options go to the Problem Tab page.

Analysis Tab

Pile/Pier Behavior allows linear or nonlinear material behavior.

Cap Behavior allows bearing capacity of cap to be included. The "Axial Bearing Effects" option is used to model the soil reaction on the bottom of the pile cap. This is done by assigning vertical soil springs to each of the nodes in the pile cap. The "Gap to Soil" parameter is used to specify an initial gap between the bottom of the pile cap and the ground surface. If the loading is sufficient to close this gap, then the analysis will consider the vertical soil reaction on the pile cap. Otherwise, the vertical soil reaction will not be considered.

The Soil Behavior option "Include Soil in Analysis" is enabled by default and causes the program to model soil in the analysis. Unchecking this option removes the soil and requires the user to enter pile tip spring stiffness to restrain the model. Use very large springs since the stiffness is only added on the diagonal.

Print control options determine what information is printed in the output file.

Figure A24: Analysis Tab

Choose options in the following categories:

4. 4. 4. 4. 4. 4. 4. 4. Soil Behavior

5. 5. 5. 5. 5. 5. 5. 5. Iteration Control

6. 6. 6. 6. 6. 6. 6. 6. Interaction Diagram Phi Factor

7. 7. 7. 7. 7. 7. 7. 7. Analysis Type

8. 8. 8. 8. 8. 8. 8. 8. Design Options

9. 9. 9. 9. 9. 9. 9. 9. Print Control

Pile/Pier Behavior

One may select either linear or nonlinear behavior of the pier and the piles.

Linear Behavior:

• Assumes the behavior is purely linear elastic.

• Deflections do not cause secondary moments; no P-delta moments (moments of the axial force times the displacements of one end of element to another).

Nonlinear Behavior:

• Uses input or default stress strain curves which are integrated over the cross-section of the piles or pier components. Full cross-section properties must be described for non-linear analysis to be performed.

• Non-linear analysis accounts for second order effects (P-delta) as well as stiffness changes in the structure, as when concrete cracks.

Return to the Analysis Tab page.

Cap Behavior

Check "Axial Bearing Effects" to consider the soil reaction on the bottom of the pile cap in the problem. The program will then use the input soil parameters to create vertical acting soil springs, which are automatically attached to the pile cap nodes.

If "Axial Bearing Effects" is checked, the user may also enter a "Gap to Soil" value, specifying the distance from the bottom of the Pile Cap to the ground surface.

Return to the Analysis Tab page.

Section Properties

When "Transformed Section" is checked, the program calculates the transformed section properties from the input ‘Full Cross Section’ when the user specifies ‘Linear Analysis’.

Return to the Analysis Tab page.

Soil Behavior

Check "Include Soil in Analysis" to include soil in the problem.

If "Include Soil in Analysis" is unchecked, then enter the stiffness at the tip of the pile.

Use high spring values to model a rigid connection.

Return to the Analysis Tab page.

Note: If a small value is entered, the solution may not converge, because it has not been given the chance to finish the calculations. On the other hand, if a very large value is entered, the analysis may take a long time.

A typical value for the number of iterations is 60.

Enter the tolerance between successive iterations that the analysis must reach before providing a solution.

Note: This value is typically 1% of the loading.

Return to the Analysis Tab page.

Interaction Diagram Phi Factor

Check "User-defined phi" to enter a custom phi factor, or leave the option unchecked if you want to use the default value.

Return to the Analysis Tab page.

Analysis Type

The Analysis tab offers two types of analysis:

1. 1. 1. 1. 1. 1. 1. 1. Static

2. 2. 2. 2. 2. 2. 2. 2. Dynamic

Design Options

Check "AASHTO Combinations" if you want to select various AASHTO load combinations to use in the analysis.

The AASHTO tab will be enabled once this option is checked.

Load types need to be assigned to each load case when converting an existing model to an AASHTO design model. Load type assignment is done on the Load tab.

Return to the Analysis Tab page.

Print Control

Select the type of output to be printed to an output file from the following:

1. 1. 1. 1. 1. 1. 1. 1. Pile Displacements

2. 2. 2. 2. 2. 2. 2. 2. Pile Element Forces

3. 3. 3. 3. 3. 3. 3. 3. Pile Properties

4. 4. 4. 4. 4. 4. 4. 4. Missing Pile Information

5. 5. 5. 5. 5. 5. 5. 5. Pier Displacements

6. 6. 6. 6. 6. 6. 6. 6. Pier Element Forces

7. 7. 7. 7. 7. 7. 7. 7. Pier Properties

12. 12. 12. 12. 12. 12. 12. 12. Unbalanced Forces

13. 13. 13. 13. 13. 13. 13. 13. Cap Stresses/Moments

14. 14. 14. 14. 14. 14. 14. 14. Stress-Strain Curves Data

15. 15. 15. 15. 15. 15. 15. 15. Bridge/Spring Forces

16. 16. 16. 16. 16. 16. 16. 16. Interaction Diagram Data

17. 17. 17. 17. 17. 17. 17. 17. Coordinates

18. 18. 18. 18. 18. 18. 18. 18. Bridge Span Displacement

19. 19. 19. 19. 19. 19. 19. 19. Bridge Span Forces

20. 20. 20. 20. 20. 20. 20. 20. Bridge Span Properties

21. 21. 21. 21. 21. 21. 21. 21. XML Data Printing – Creates XML

output file that can be used to extract FB-MultiPier data. See FB-MultiPier XML Specification documentation.

Return to the Analysis Tab page.

AASHTO Tab

AASHTO Tab

Select the AASHTO combinations that will be used in the analysis using the following:

1. 1. 1. 1. 1. 1. 1. 1. AASHTO Load Factors Table

2. 2. 2. 2. 2. 2. 2. 2. Automated AASHTO Loads

3. 3. 3. 3. 3. 3. 3. 3. AASHTO Load Manager

4. 4. 4. 4. 4. 4. 4. 4. Wind Load Generation Table

5. 5. 5. 5. 5. 5. 5. 5. AASHTO Load Combination Preview Table

6. 6. 6. 6. 6. 6. 6. 6. Limit States to Check

Note: The AASHTO Combination option in the Design Options section of the Analysis Tab must be selected for this tab to appear.

Figure A32: AASHTO Tab

AASHTO Load Factors Table

Figure A33: AASHTO Load Factor Table

Return to the AASHTO Tab page.

Automated AASHTO Loads

Choose to include self weight and/or buoyancy cases.

For AASHTO LRFD, self weight is included in the "DC" case and buoyancy is included in the "WA" case.

For AASHTO LFD, self weight is included in the "D" case and buoyancy is included in the "B" case.

AASHTO Load Manager

The AASHTO Load Manager manages the type and number of load cases in your model. Changes made with this manager apply to every pier.

Figure A34: AASHTO Load Manager Dialog

To add a new load case, select a load case from the "Available Types" list. Then click the "Add" ( << ) button. This will add the selected load case to the "Defined Load Cases" list.

To remove a defined load case, select a load case from the "Defined Load Cases" list. Then click the "Remove" ( >> ) button.

To change the number of load cases for a particular load type, select a load case from the "Defined Load Cases" list. Load case types which can vary in number will be followed by parenthesis and a number. Example: Live Load (1). In the box below the "Defined Load Cases" list, change the value to the desired number of load cases. This will change the number of load cases for that load type in the "Defined Load Cases" list.

Note: certain load case types are grouped together. Example, "Wind on Structure" and "Wind on Live Load". Changing the number of cases for one of these types will automatically change the number of cases for the other type.

Wind Load Generator

Enter the wind load parameters.

Click ‘Generate Wind Load Cases’ to convert the wind load to loads at the bearing locations and automatically create wind load cases. Depending on the problem type you will see one of the following dialog boxes.

This dialog appears for the General Pier and Pile Bent Bridge problem type.

Figure A35-a: Wind Load Generation Dialog for Single Pier

igure A35-b: Wind Load Generation Dialog for Multiple Piers

A wind angle of zero degrees applies all of the wind in the transverse direction. The equations used in the wind load generation are found here.

AASHTO Load Combination Preview Table

Figure A36: AASHTO Load Combination Preview Table

Limit States to Check

Select the limit states to check in the analysis.

Note: The program does not display (or analyze) a load combination unless the load types expected in that combination are defined. For example, the STRENGTH-III load combination will not be considered until a dead load type (DC) and a wind load type (WS) are defined. Dead, live, and wind load types are considered mandatory to generate load combinations. All other load types are optional. Check the load combination preview in the AASHTO tab to confirm the generation of specific load combinations.

Dynamics Tab

Dynamics Tab

The Dynamics Tab provides various options for controlling a dynamic analysis.

Figure A37: Dynamics Tab

Analysis Type

Two dynamic analysis types are available.

This analysis type requires the user to select the number of modes to use in the analysis. Check the modal contribution factors in the printed output file to ensure that at least 90% of the dynamic response is accounted for.

The reported analysis results do not include the effect of static loads (i.e. self weight). Adding the static results and response spectrum results may not be conservative and is left to engineering judgment.

Damping

Three types of damping input are available.

1. 1. 1. 1. 1. 1. 1. 1. Rayleigh damping. The damping is

proportional to the mass and stiffness. Factors can be entered for the pier, piles, and soil.

2. 2. 2. 2. 2. 2. 2. 2. Concentrated dampers. These

dampers are applied using the Mass/Damper tab.

3. 3. 3. 3. 3. 3. 3. 3. Hysteretic damping. This form of

damping is available when gap modeling is enabled for the lateral soil response as well as for nonlinear pile and pier material behavior.

Mass

Two types of mass modeling are available.

1. 1. 1. 1. 1. 1. 1. 1. Consistent (distributed) mass.

2. 2. 2. 2. 2. 2. 2. 2. Lumped (concentrated) mass.

Time Stepping Parameters

Three types of time stepping options are available.

1. 1. 1. 1. 1. 1. 1. 1. Average acceleration (Newmark).

2. 2. 2. 2. 2. 2. 2. 2. Linear acceleration (Newmark).

3. 3. 3. 3. 3. 3. 3. 3. Wilson-Theta.

Enter a constant value for the time step to use in the analysis. Enter the number of time steps to consider in the analysis.

For a Modal Response Spectrum analysis, enter the number of modes to consider and the damping ratio used for the response spectrum.

Two types of load functions are available for a dynamic analysis. 1. Load (force vs. time)

2. Ground Acceleration (acceleration vs. time). The gravity factor is used in conjunction with the acceleration record. If the acceleration is in terms of g’s, then the gravity factor would be either 386.4 in/sec2 or 9.81 m/sec2. If the acceleration is already in terms of an acceleration unit, then the gravity factor should be entered as 1.0.

Ground Acceleration (acceleration vs. frequency). For response spectrum anaylsis.

Click the "Edit Load Functions " button to define one or more load functions to apply to the model.

Analysis Type Dynamic

Time Step Integration

Modal Response

#Nodes

Global Mass

Damping

Time Stepping Parameters

Linear Acceleration

Wilson Theta

Time Step Sec.

#Steps

Rayleigh Damping Factors

Mass Stiffness

Pier

Piles

Model Analysis Damping

Damping Ratio

Time Functions

Applied Load (Load vs Time)

Ground Acceleration

G= 366.2 in/sec^2

Scale Factor

Acceleration = Scale Factor *9* Time Function

Edit Load Functions

The Edit Load Functions dialog is used to define one or more load functions for a dynamic analysis.

Figure A38: Edit Load Function Dialog

The "Load Function" combo box contains a list of all defined load functions. Select "Add Load Function" in the combo box to create a new load function. When the ground acceleration option is specified, only one load function can be defined and is automatically applied to the entire model. For this case, select "Change Load Function" in the combo box to select a different function.

Click the "Read From File" button to retrieve an existing load function from a text file. Predefined load functions have the following extensions:

".dlf" Load vs. Time

".acc" Acceleration (ground) vs. Time

".spt" Acceleration vs. Frequency (response spectrum)

The format of the text file should contain paired data (time, load), (time, acceleration), or (freq., acceleration). The file can have between one and four pairs per line (maximum 80 characters per line).

Click the "Edit Function Values " button to display the "Load Function Edit Table", which is a spreadsheet-style grid for customizing the data points.

Load Function Edit Table

The "Load Function Edit Table" displays the paired values used in the load function. Rows can be inserted or deleted as needed. The "Update Table" button sorts the values according to increasing time. You can drag and drop a range of data points from a spreadsheet directly into the table.

Figure A39: Load Function Edit Table Dialog

Pushover Tab

Pushover Tab

Click on the Run Pushover Analysis checkbox to activate the pushover analysis module.

There must be 2 load cases. The first load case is used to apply permanent loads that will not be incremented (i.e. self weight). The second load case is used to specify the load that will be incremented.

Enter the number of pushover steps and the load increment factor. The load increment factor multiplies the loads in the second load case to create an accumulating load that is applied until convergence cannot be achieved.

For example, a load increment factor of 1.0 would add 100% of the original load to each

incremental load case. If the original load increment was 10 kips, the second load increment would be 20 kip load, the third increment 30 kips, and so forth for the number of load steps. The failure load is printed to the output file when a load is reached that can not converge to a solution.

Pier Data Edit

Pile and Cap Tab

Pile and Cap Tab

Use the Pile/Shaft Drop down to select standard pile from the database.

You can add cross sections to the database in the edit mode. Click the 'Edit Cross Section' button to customize the pile/shaft.

The number of piles in the X and Y-directions is used to create a grid for positioning the piles. Piles not shown at a grid position are labeled as missing.

Enter data for the pile and cap in the following fields:

1. Pile Cap Grid Geometry 2. Pile Cross Section Type 3. Pile to Cap Connection 4. Pile Length Data 5. Pile/Shaft Type 6. Pile Cap Data

Figure A41: Pile and Cap Tab

Pile Length Data

Enter the elevation of the tip in the Tip Elevation text box.

Note: The tip elevation must be negative.

Figure A42: Free Length of Pile Above Soil

Return to the Pile and Cap Tab page.

Pile Cross Section Type

A different edit window appears depending upon the type of cross section selected.

If "Linear Properties" is selected and the "Edit Cross Section" button is clicked, then the Linear Pile Properties window will appear.

Pile/Shaft Type

Choose the type of pile from the drop-down list.

Figure A43: Pile Database Options

Return to the Pile and Cap Tab page.

Pile to Cap Connection

Pile Cap Data

Enter the elevation of the pile cap in the "Head/Cap Elevation" text box.

Check the "Apply Overhang" box to enter the over hang of the pile cap.

Click the "Edit Pile Cap" button to enter the following properties for the pile cap:

1. Young’s Modulus 2. Poisson’s Ratio 3. Thickness 4. Unit Weight

Return to the Pile and Cap Tab page.

Pile Cap Grid Geometry

Enter the number of grid points in the X and Y directions.

Where d is the standard dimension of the cross section (the width of a square pile or the diameter of a circular pile).

Note: With no over hang specified the program automatically places piles at all grid points.

For the constant and variable spacing options see the Grid Spacing Table.

Return to the Pile and Cap Tab page.

Grid Spacing Table

If constant spacing is selected from the pull-down menu in the Pile Cap Grid Geometry section on the Pile and Cap Tab page, then only the "Constant Spacing" text box is editable.

Enter the custom spacing in both directions into the text box.

Note: Entering a constant spacing will also affect the overhang distance.

Otherwise, if variable spacing is selected, then the "Constant Spacing" text box is "grayed out" and the only individual spread sheet elements are editable.

Enter the custom spacing between each pile into the corresponding fields of the spreadsheet.

Figure A45: Grid Spacing Table

Return to the Pile Cap Grid Geometry section.

Edit Cross Section

Gross Section Pile Properties

Gross Pile Properties

Modify the properties of a gross pile cross section in the following fields:

1. Pile/Shaft Segment List 2. Pile Set Info

6. Segment Dimensions

Figure A46: Gross Pile Properties Dialog

Return to the Pile Cross Section Type page.

Add and remove pile/shaft segments.

Return to the Linear Pile Properties or Full Cross-Section Pile Properties page.

Pile Set Info

Add and remove pile sets (types). This allows the user to use different pile types for each pile.

Return to the Linear Pile Properties or Full Cross-Section Pile Properties page.

Pile Sets Tutorial

Database Section Selection

If the "Use Database Section" option is selected, the user can select from a predefined set of cross-sections.

In the Linear Pile Properties page, there is only one option (Linear Pile) when you click on the "Retrieve Section" button.

Figure A47: Pile Database Options

If the "Modify Current Section" option is selected, the user can customize the current cross section.

Furthermore, the user can also save custom cross sections by clicking the "Save Section" button.

Return to the Linear Pile Properties or Full Cross-Section Pile Properties page.

Section Type

Select a cross section type from the following:

2. Square Pile

3. H-Pile

Note: this option is only available if the "Modify Database Section" option is selected.

Return to the Linear Pile Properties page.

Segment Dimensions

Enter the following data for the dimensions of the segment:

1. Length

2. Area

3. Diameter—Only available for a circular pile 4. Width—Only available for a square pile 5. Depth—Only available for a square pile

6. [Unit] Weight

Note: this option is only available if the "Modify Database Section" option is selected.

Return to the Linear Pile Properties page.

Section Properties

3. Torsional Inertia

4. Young’s Modulus

5. Shear Modulus

Note: this option is only available if the "Modify Database Section" option is selected.

Return to the Linear Pile Properties page.

Full Cross Section Pile Properties

Full Cross-Section Pile Properties

Modify all of the properties of a pile cross section in the following fields:

1. Pile/Shaft Segment List 2. Pile Set Info

3. Database Section Selection 4. Section Details

5. Section Type 6. Material Properties 7. Section Dimensions

Figure A48: Full Cross Section Properties Dialog

Return to the Pile Cross Section Type page.

Select a segment from the "Section List" and a pile set from the "Pile Set" list to edit.

Return to the Full Cross-Section Pile Properties or the Full Pier Component Properties page.

Section Dimensions

The fields in which one can enter data depend upon the type of cross section selected.

Circular Section: 1. Length 2. Diameter 3. Unit Weight Rectangular Section: 1. Length 2. Width 3. Base 4. Unit Weight H-Pile: 1. Length 2. Unit Weight Pipe Pile: 1. Length 2. Diameter 3. Thickness 4. Unit Weight

Section Type

Section Type

Select a cross section type from the following:

The "Edit Section Contents" button yields different windows depending upon the type of cross section selected.

1. Circular Pile 2. Square Pile 3. H-Pile 4. Pipe Pile

Note: this option is only available if the "Modify Database Section" option is selected.

Return to the Full Cross-Section Pile Properties page.

Circular Section Properties

Circular Section Properties

Enter the data for a circular cross section in the following fields:

1. Edit Bar Groups 2. Group Data

3. Confined Concrete Option 4. Shear Reinforcement

Figure A49b: Circular Cross Section Properties Dialog - Percentage Group Method

Percentage Steel Tutorial

Return to the Section Type page.

Edit Bar Groups

Add or remove rebar groups to or from the cross section.

Percentage Steel Tutorial

Group Data

There are two methods for entering bar group data; Custom and Percentage.

Custom:

1. Enter the number of bars in the group in the "Number of Bars/Strands" text box. 2. Next, select the type of layout for the bars from the "Group Type" options—circular or rectangular.

3. If the rectangular option is selected, choose the orientation of the group of bars from the "Group Orientation" options—horizontal or vertical.

4. Then, enter the area of the bars and, depending upon the layout, the diameter of a circular layout or the starting coordinates of a rectangular layout.

5. Click the Add button to add the bar group to the section.

6. Click the Apply button to update any changes made to the bar group. 7. Repeat steps 1-4 to add more groups of bars/strands.

8. Click OK when done to exit the dialog.

Percentage:

1. Enter a Reinforcement % (the % of the cross section area that is steel)

2. Enter the cover. Cover 2 is the distance between the cross section edge and the steel bars, in the 2 direction. Cover 3 is the distance between the cross section edge and the steel bars, in the 3 direction.

3. Enter the Minimum Spacing (minimum distance between two bars). 4. Click the Update Bar List button to display the available bar options. 5. Select a bar type from the Bar Type list box.

6. Click the Apply button to apply the steel to the cross section, or double click the selected Bar Type. Any existing bar data will be deleted.

7. Click OK when done to exit the dialog.

For both methods:

Choose between mild steel or prestress for the type of steel in the group.

If prestress is chosen, then enter the prestress after losses.

Return to the Circular Section Properties or the Rectangular Section Properties page.

Confined Concrete Option

Choose between "Shell & Spiral", "Spiral Only", and "None" to determine the type confinement for the concrete.

Figure A50: Confined Concrete Options

Enter values for the yield stress, shear spacing, and bar diameter ( Note: Not available with the "None" option).

Note: A shell thickness must be entered in the "Shell Thickness" text box in order to select Shell and Spiral.

Return to the Circular Section Properties page.

Shear Reinforcement

Select either spiral or tied for the type of shear reinforcement.

Return to the Circular Section Properties page.

Miscellaneous

Enter data using the following fields:

Enter the shell thickness in inches in the "Shell Thickness" text box.

Enter the diameter of a void in the member in inches in the "Void Diameter" text box.

Click the "H-Pile Properties" button to edit the properties of an h-pile embedded in he circular cross section.

Return to the Circular Section Properties page.

Confined Concrete Model

CONFINED CONCRETE MODEL

Effective confinement has been shown to considerably enhance the compressive strength and ductility of concrete. The strength and ductility enhancement from confinement of the concrete will of course cause corresponding

increases in the axial and flexural strength and ductility of reinforced concrete columns or piles. The confining effect of the column or pile may be accomplished by the used of circular hoops, spiral reinforcement, and an external steel jacket.

In the case of internal confinement i.e. spirals or circular hoops, the cover concrete will be unconfined and will become ineffective after the maximum compressive strain of the concrete has been attained, but the confined core will continue to carry stress at high strains. The compressive stress-strain response used for the core and cover concrete are those obtained by the Mander model (Mander and Priestly, 1988) for confined and unconfined concrete, respectively.

In the case of an external jacket, the jacket will provide confinement to the cover concrete and the inner concrete will be doubly confined by the jacket and the internal confinement due to the circular hoops or spirals. Although the steel area of the shell (casing) is not considered for direct bending or axial strength the confining effects to the concrete are. The compressive stress-strain response used for the core and cover concrete are those obtained by the modified Mander model. The Mander model was modified for the confining effects of the external shell by Priestly et al (1991).

Mander Models for Confined Concrete

Both the Mander and modified Mander models use the following equation for the longitudinal compressive stress of confined concrete:

'

* *

1

x r

f

f

r

x

=

− +

f ’cc is the compressive strength of the of confined concrete

x is given by: ' c cc

x

ε

ε

=

' ' ' '

1 5*

1

f

f

ε ε

















=

_

+

_

−

_

_







_

_







f ’co is the unconfined compressive stress of the concrete

e’co is the unconfined concrete compressive strain, adopted as 0.002

The parameter r is given by:

sec c c

r

E

E E

=

−

ε’

ε

ε’

f’

f’

Confined Concrete

Unconfined

Concrete

ε

Compressive Strain ε

Esec is the secant modulus for confined concrete, defined with respect to f ’cc and e’cc and is given by:

' ' sec cc cc

f

E

ε

=

For f ’cc, the confined concrete strength, Mander used the five-parameter failure criterion proposed by William and Warnke and the tri-axial test data of Schickert and Winkler. In the case of circular columns confined by circular hoops or spirals, the confined concrete compressive stress has been shown to be:

' ' ' ' ' '

2.254 1 7.94

2

1.254

f

f

f

f

f

f









=

_

+

−

−

_









f ’l is effective confining pressure, and may be obtained from the equilibrium of internal forces acting on the dissected sections shown in Figure D9

For the cover concrete in columns, assuming uniform yield of the jacket, the equilibrium of forces requires:

(

)

2

2

f t

f

t

D

=

−

f ’lj is the lateral confining pressure acting on the cover concrete Dj is the outside diameter of the steel jacket

tj is the thickness of the steel jacket fyj is the yield strength of the steel jacket

D j J a c k e t fy j fy j f ’l h ds fy h fy h H o o p

+

=

The confining ratio for the steel jacket is defined as:

(

4

2

)

t

t

D

ρ

≡

−

Substituting into equation d35 we obtain

'

1

2

lj sj yj

f

=

ρ

f

Eqn. d37

By using f ’l = f ’lj in equation d34, the compressive strength of the cover concrete confined by the steel jacket can be determined.

Additional confinement is provided to the concrete core by the transverse reinforcement. The additional lateral pressure, f ’lh, may also be determined from the equilibrium of forces. Assuming uniform yield of the transverse steel yields the following equation:

'

2

s

f A

f

_k

d

=

ds is the diameter of the concrete core defined along the center line of the confining steel

s is the

vertical spacing of the transverse steel

fyh is the yield strength of the transverse reinforcement Ash is the cross-sectional area of the transverse steel

The confinement effectiveness coefficient, ke, is defined as:

e e cc

A

k

A

≡