Design and Rating of Steel Bridges

Transcription

1 2014 Bentley Systems, Incorporated Parametric and Integrated Bridge Design LEAP Bridge Steel Steve Willoughby Design and Rating of Steel Bridges Bentley Systems, Incorporated 1

2 Discussion Topics LEAP Bridge Steel Overview 3D Modeling Workflow General commands Roadway Commands and Civil data import Superstructure Modeling Substructure Modeling Analysis Design Substructure Analysis/design using RC-PIER Load Rating Export to MicroStation Bentley Systems, Incorporated LEAP Bridge Steel Overview Supported bridge configurations Simple and continuous spans Straight and curved bridges Standard rolled shapes and welded I girders 6 th Edition (7 th coming soon) of the AASHTO LRFD Bridge Design Specification, and 2nd Edition of the AASHTO Manual for Bridge Evaluation. Provides: Parametric modeling Streamlined analysis Design code checking Load Rating Transparent dead and live load analysis by STAAD.Pro Bentley Systems, Incorporated 2

3 LEAP Bridge Steel Overview General Commands Libraries Tutorials MS export Modeling Commands Roadway Superstructure Substructure Analysis, design, rating Bentley Systems, Incorporated General Commands View toggles Add Remove Refresh Bridge Libraries DTM view options Export model to MicroStation Input Data Report RSS Feeds Tutorials Bentley Systems, Incorporated 3

4 General Commands - Libraries Libraries store Appurtenances Vehicles/live load information Material tables Users can add and share library data Library elements are selected during the modeling process Bentley Systems, Incorporated General Commands Appurtenance Library Parapets Medians Sidewalk Railings General Weights are included automatically as DC2 load on the model Bentley Systems, Incorporated 4

5 General Commands Material Library Steel Concrete Reinforcing steel Bentley Systems, Incorporated General Commands Vehicle Library Define Truck loads Lane loads Live load groups Bentley Systems, Incorporated 5

6 Workflow 4/21/2015 Bridge Modeling Workflow Roadway Elements Import from Civil InRoads, GEOPAK, MXROAD Enter in LBS Superstructure Substructure Analysis Design Load Rating Bentley Systems, Incorporated Roadway Element Commands Roadway elements define the horizontal, vertical and cross section geometry for the bridge deck The cross section defines the left and right edges of the slab Tapered cross sections define tapered slabs Bentley Systems, Incorporated 6

7 Import From MicroStation Import alignments and beam paths directly from MicroStation Bentley Systems, Incorporated Roadway Elements Roadway Definition Combines alignment, profile and cross section to define roadway/slab surface and edges Bentley Systems, Incorporated 7

8 Superstructure Commands Define the components of the superstructure 3D bridge model automatically updated geometrically and for loading 3D Model can be visualized at every stage of model definition Bentley Systems, Incorporated Superstructure Pier & Abutment Locations Locate bridge support centerlines Define as pier or abutment Assign skew, if any Can be offset to alignment Define bearing locations Changes are automatically reflected in the overall model Bentley Systems, Incorporated 8

9 Superstructure Deck Slab Define concrete deck longitudinal bounds When the deck is defined as multiple slab units, these can be used in the Deck Placement Sequence Command Sacrificial wearing surface included for dead load calculation Slab is considered non-composite until shear connectors are added Bentley Systems, Incorporated Superstructure Deck Reinforcing Steel Used in section property calculations as stipulated by the AASHTO Spec. Strength: Article c sections in negative bending Service: Article Used to determine minimum steel requirements per Article Bentley Systems, Incorporated 9

10 Superstructure Member Groups Define the member layout or framing plan straight or curved Simple or continuous spans Define from MicroStation elements A single bridge model can contain multiple member groups Member groups can be copied in their entirety (including members) to different locations Bentley Systems, Incorporated Superstructure Standard Section List Select standard shapes for Cross frames Main members Bentley Systems, Incorporated 10

11 Superstructure Member Definition Define member geometry using schedule based methodology Web transitions Copy members Hybrid girders Welded plate or standard section Bentley Systems, Incorporated Superstructure Cross-Frame / Diaphragm Definition Struts, X, V, inverted V Build from standard shapes Control orientation of members Analyze as frame or truss Used in grillage model as equivalent beam using methods from NCHRP Report 725 Individual member forces computed Bentley Systems, Incorporated 11

12 Superstructure - Cross-Frame / Diaphragm Location Locate per bay or entire bridge Can be skewed Wizards available to assist layout Manipulate individually Bentley Systems, Incorporated Superstructure Stiffener Definition and Location Define bearing, connection plates or shear stiffeners Wizards available to assist locating stiffeners Bentley Systems, Incorporated 12

13 Superstructure Shear Connector Definition and Location Define stud, channel or generic Locate along members by range with longitudinal and transverse spacing Define regions of composite action Fatigue and Strength checks Bentley Systems, Incorporated Hinge Locations Define locations of moment release along any member Bentley Systems, Incorporated 13

14 Superstructure Appurtenance Locations Locate appurtenances such as parapets, medians, sidewalk, etc. DC2 load automatically calculated Parapets define travel way for live load Bentley Systems, Incorporated Substructure Piers and Abutments Piers Multi-column Hammerhead Abutments Pile cap Stem wall All geometry defined in LBS and passed to RC-PIER for design Bentley Systems, Incorporated 14

15 Substructure Support Conditions Control movement at bearing locations Pinned Roller Fixed Float Directional Bentley Systems, Incorporated Analysis Commands Point of Interest Locations Deck Placement Sequence Loads Analysis Design Rating Substructure Design/Analysis Bentley Systems, Incorporated 15

16 Analysis Point of Interest Locations Locations where analysis results and design code checks Auto located at X-frames At section breaks User defined locations Bentley Systems, Incorporated Analysis Deck Placement Sequence Bentley Systems, Incorporated 16

17 Analysis Deck Placement Sequence Provides means to analyze stress effects in the steel and concrete slab as slab segments are poured in each stage The process is closely tied to Constructability checking (6.10.3) LBS automatically generates stages, load cases and load combinations User defined load cases at any stage Deck overhang, construction and finishing machine loads can be added Bentley Systems, Incorporated Analysis Deck Placement Sequence Simulation Slab 1 Slab 2 Slab 3 Slab 4 Slab 5 Plan View of Bridge Bentley Systems, Incorporated 17

18 Analysis - Loads The Loads command allows entry of load cases (right) and Load combinations (left) Loads Cases can be: Permanent DC1 dead load Superimposed DC2 dead load FWS/Utility DW dead load Uniform temperature Pedestrian Wind and Live load Load cases and combinations can be user defined for any stage. Load Combinations Load Cases Bentley Systems, Incorporated Analysis Dead Load Most dead load cases are auto generated and updated as the model changes Dead load cases can be user defined DC1 loads applied to the non-composite structure DC2 loads applied to the long term composite structure (N=3N) DW loads applied to the long term composite structure (N=3N) Bentley Systems, Incorporated 18

19 Analysis Live Load Live load cases consist of: Vehicles Lane Combinations of vehicle and lane Notional effects Special envelope and optional factors Optional side by side load Live loads applied to the short term composite structure (N=N) All live loads are stored in the Vehicle Library Bentley Systems, Incorporated Analysis Load Combinations LEAP Bridge Steel auto generates default load combinations for construction and final stages Construction stage loads include all automatically generated loads from previous stages (for stress accumulation) User defined load combinations can be added to any stage Construction stage combinations default to Strength I Final stage load combinations default to Strength I, Service II and Fatigue Bentley Systems, Incorporated 19

20 Analysis Structural Analysis There currently are two analysis options Line girder Grillage Line Girder Live load distribution factors calculated automatically Analysis performed for all dead and live load cases Analysis takes into account structure stiffness variations in each stage Results displayed in report and graphic form Results exported to multiple formats: PDF, Excel, HTML, RTF, MHT, Text, JPG, PNG Bentley Systems, Incorporated Analysis Results Bentley Systems, Incorporated 20

21 Analysis Results Camber Diagrams Bentley Systems, Incorporated Analysis - Reports Dead Load Node displacements Girder forces Cross frame forces Support reactions Live Load Distribution factors Girder forces Node displacements Cross frame forces Support reactions Bentley Systems, Incorporated 21

22 Analysis - Design Design code checks per AASHTO LRFD 6 th Edition (7 th Edition updates coming) Load rating per Manual for Bridge Evaluation, 2 nd Edition Detail reports organized by member and Point of Interest Code check failures are flagged Bentley Systems, Incorporated Analysis Design Reports Under / Over Design Section Properties Section Limits Factored Forces Constructibility Service Limit State Strength Limit State Fatigue Factored Stresses Intermediate values Shear connectors Bentley Systems, Incorporated 22

23 Analysis Design Reports Bentley Systems, Incorporated Analysis - Rating LBS 1.0 performs design Inventory and Operating rating Rating models are copied from the design model or other rating models multiple rating models possible User defined combinations Bentley Systems, Incorporated 23

24 Analysis Substructure Design/Analysis Substructure geometry and superstructure description are seamlessly passed to RC-PIER RC-PIER performs analysis and design Bentley Systems, Incorporated Export to MicroStation The complete bridge model is exported to MicroStation as a 3D intelligent model Bentley Systems, Incorporated 24

25 Steel Bridge designed by LEAP Bridge Steel Bentley Systems, Incorporated Bentley Systems, Incorporated 25

26 Upcoming Events Important Dates Save the Date Bentley LEARNing conference May 6-7, 2015 Indianapolis, Indiana Bentley Bridge SIG Meeting included Bentley Bridge SIG June 11, D Modeling with LEAP Bentley Systems, Incorporated Bentley Systems, Incorporated 26