MIDAS Elite Engineer. Peter Revees-Toy Director, Tony Gee, UAE

Transcription

1 MIDAS Elite Engineer Peter Revees-Toy Director, Tony Gee, UAE

2 MIDAS ELITE ENGINEER TALK Case Studies of Steel Bridge Design using FEM Analysis

3 Contents 1. Introduction of Case Studies 1) Bahrain Bridge 2) Doha Metro Station Roof 3) Doha Metro Temporary Bridge 2. Other Project Applications 3. Useful Functionality

4 1. Introduction of Case Studies 1. Bahrain Bridge 2012 Temporary works and erection stress analysis Construction stages, lift off supports, support displacement and structural interaction 2. Doha Metro Roof 2015 Permanent Works Complex steel frame, connection modelling 3. Doha Metro Greenline 2015 Temporary Bridge for Tunnel Boring Machine Plate and frame analysis

5 1) Bahrain Bridge Client: US Navy Contractor: Contrack TG Role: Erection stress analysis Installation master plan Temporary Works design Installation Supervision Bow String Arch Bridge, 122m Span, 6000T

6 1) Bahrain Bridge_What we needed to model Construction stages Cable Stressing and load transfer Bridge beam interaction

7 1) Bahrain Bridge_How we modelled Bridge modelled in midas Civil Full 3D line element model with all construction stages, modelled as a gr illage Tension only elements for hangers, stressed in sequence, with rigid links for connection Compression only supports to simulate false work during casting Forced displacement of supports to simulate jacking and transfer load Modelling of lifting girder with the bridge

8 1) Bahrain Bridge_Challenges of Modelling Anomalies occur due to point connections Arch to deck connection shows peak but within the foot connection A common effect in most FE packages Anomalies due to grillage Transverse bending induced in the longitudinal deck members Deck is actually a single member so the effect can t occur

9 1) Bahrain Bridge_Construction Stage Analysis Enables accurate build up of forces Provides the build up of defection for the pre-camber Enables stresses in members to be checked at each step of the erection process The CS analysis identified flexibility in the structure that the original designer had not considered

10 1) Bahrain Bridge_Construction Stage Analysis

11 1) Bahrain Bridge_Iterative Pre-camber derivation Reason arch stiffness changes with pre-camber Final shape modelled initially Deformed shape then recorded and reverse modelled This process was repeated five or six times to converge on the correct pre-camber

12 1) Bahrain Bridge_Transfer to SPMT Tension is applied to the cables (approx 20kN) This nominal tensioning takes up the slack and the cables become effective. The deck is still fully supported by the falsework at this time. The bridge is then jacked up by the SPMT at the bearing locations. The deck load is progressively transferred and the bridge sags to its final profile.

13 1) Bahrain Bridge_Load transfer by reaction

14 1) Bahrain Bridge_Lifting beam interaction

15 1) Bahrain Bridge_During installation

16 1) Bahrain Bridge_Working through the night

17 1) Bahrain Bridge_Bridge Deck Connection

18 1) Bahrain Bridge_Video Demo ~11 56

19 2) Doha Metro Station Roof Major Station Building application but behaviour of a bridge Use of solid elements imported into line model for complex connections. Connection dxf exported from midas Civil, manipulated in CAD and imported into midas FEA. Connection modelled in full in midas FEA, meshed and then inserted in to midas Civil via MCT(Text fomate)

20 2) Doha Metro Station Roof_Doha Metro Line

21 2) Doha Metro Station Roof_Msheireb Station Major Station Building application but behaviour of a bridge Use of solid elements imported into line model for complex connections. Connection dxf exported from midas Civil, manipulated in CAD and imported into midas FEA Connection modelled in full in midas FEA, meshed and then inserted in to midas Civil via MCT(Text fomate)

22 2) Doha Metro Station Roof_Msheireb Station

23 2) Doha Metro Station Roof_Education City

24 2) Doha Metro Station Roof_What we needed to model Steel frame with complex geometry Correct connection relationships Temporary support condition during construction Complex full moment connections within the steel frame for stress check Verification of constructability

25 2) Doha Metro Station Roof_How we modelled Full 3d frame model in midas Civil Use of construction stages to control articulation of supports Complex full moment connections modelled in midas FEA Connections imported back into Midas Civil frame model for direct stress assessment

26 2) Doha Metro Station Roof_Step 1 Divide the incoming elements to at connection Export the elements immediately connected to the node including shape and thickness

27 2) Doha Metro Station Roof_Step 2 Import into AutoCAD or similar (can be done in FEA directly) Rationalise the geometry Define additional connection elements, such as fin plates and splice plates etc.

28 2) Doha Metro Station Roof_Step 3 Import the AutoCAD DXF into midas FEA Create surfaces at member ends and extrude Working from the primary elements first subtract and fuse using the Boolean commands.

29 2) Doha Metro Station Roof_Step 4 Use the auto mesh function setting a mesh size similar to the plate thickness. Depending on geometry set mesh controls a local discontinuities to help mesher

30 2) Doha Metro Station Roof_Step 5 Set material number to the same as midas Civil Re number the nodes and elements Export to MCT and then import in to midas Civil Maintain the same coordinate system through out. Connect the face of the solid to frame with rigid link. Large coordinates presented an glitch

31 2) Doha Metro Station Roof_Solid modelling top tips Follow the same convention each time Don t rush or cut corners Make us of local coordinate systems to ensure planar surfaces Label objects clearly including tools Use overlapping tools Subtract or fuse progressively Avoid narrow discontinuities

32 3) Doha Metro Temporary Bridge TBM Bridge Spanning the excavation for the Blue Line 36m single span Shallow depth Minimises site operations Supports TBM and MSV in different configurations Line Model and Plate model Plate model enabled detailed consideration of deflections at different fabrication stages

33 3) Doha Metro Temporary Bridge_What we needed to model Complex box steel box girder bridge Used in two different configurations Ground bearing Simply supported Models to allow for variations in loading and detailed connection requirements Accurate plate model required for stiffness and local effects

34 3) Doha Metro Temporary Bridge_Cross-section

35 3) Doha Metro Temporary Bridge_How we modelled Grillage models for bending design Plate model for deflection analysis Plate model for stiffener design and plate buckling

36 3) Doha Metro Temporary Bridge_How we modelled Compression only links at connections Moving load analysis for MSV

37 3) Doha Metro Temporary Bridge_Stress plot example Stress concentrations at links

38 3) Doha Metro Temporary Bridge_During Installation

39 3) Doha Metro Temporary Bridge_During Installation

40 3) Doha Metro Temporary Bridge_Bridge in use

41 3) Doha Metro Temporary Bridge_Bridge with MSV

42 2. Other Project Applications 1. Assessment of radial forces in solid element modelling Use of embedded tendons 2. Assessment of equilibrium stresses between blisters in box girders Use of Embedded Tendons 3. Track Structure interaction

43 2. Other Project Applications Radial Tendon Forces

44 2. Other Project Applications Radial Tendon Forces

45 2. Other Project Applications Embedded Tendons

46 2. Other Project Applications Shear key failure

47 2. Other Project Applications Track Structure Interaction Incredibly Fast and Easy

48 3. Useful Functionality MCT Command Shell Structural Wizards Rendering and dxf output capability Use of Construction Stage to simulate changes in stiffness

49 THANK YOU Contact: