recent Research on Steel Bridges
-
Upload
shakirhamid6687 -
Category
Documents
-
view
217 -
download
0
description
Transcript of recent Research on Steel Bridges
![Page 1: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/1.jpg)
Recent Research on Steel Bridges
1
2012 CTR Symposium
Michael EngelhardtTodd Helwig
Karl FrankEric Williamson
Richard Klingner
Investigators:
![Page 2: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/2.jpg)
Recent Research on Steel Bridges
2
• Project 0-5701Cross Frame and Diaphragm Layout and Connection DetailsCompleted 2010
• Project 0-6564Improved Cross Frame DetailsOn-Going Research
• Project 0-6719Strengthening Continuous Steel Girders With Post-Installed Shear ConnectorsOn-Going Research
![Page 3: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/3.jpg)
Cross Frame and Diaphragm Layout and Connection Details
TxDOT Project 0-5701Completed 2010
Graduate Research Assistants: Craig Quadrato, Wei Wang, Andrew Wahr, Anthony Battistini
Faculty Researchers: Todd Helwig, Karl Frank, and Michael Engelhardt
TxDOT Project Coordinator: Kenneth OzunaTxDOT Project Director: Ken Lin
3
![Page 4: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/4.jpg)
Research Objectives
1. Investigate cross frame connection details for skewed steel girder bridges
2. Investigate different bracing layouts
3. Improve stability and fatigue performance
4
![Page 5: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/5.jpg)
5
Bearing Stiffeners
Bent Plate
Cross Frame
Bent Plate Detail for Connecting Cross-Frames to Girders at a Skew:
Current TxDOT Practice:
![Page 6: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/6.jpg)
6
Key Issue: Flexibility of Bent Plate Connection Detail
Key Objective: Develop Improved Connection Detail forAttaching Skewed Cross-Frames to Girder
![Page 7: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/7.jpg)
Proposed Improved Connection:Half-Pipe Stiffener
Warping restraint
Half-Pipe Stiffener
Cross Frame
7
• Stiffer cross-frame to girder connection• Provides warping restraint for girder – increases
girder stability
Potential Benefits of Half-Pipe Stiffener:
Bearing Stiffeners
Bent PlateCross Frame
![Page 8: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/8.jpg)
8
![Page 9: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/9.jpg)
Major Research Activities
• Laboratory Tests– Connection Tests– Fatigue Testing– Large Scale Tests on Two and Three Girder Systems
• Computational Modeling
9
![Page 10: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/10.jpg)
Connection Testing and Analysis
10
![Page 11: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/11.jpg)
Fatigue Testing and Analysis
11
![Page 12: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/12.jpg)
12
![Page 13: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/13.jpg)
Large Scale Testing
13
![Page 14: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/14.jpg)
Computational Modeling
14
![Page 15: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/15.jpg)
Results
Bent Plate Connection:– acceptable for end frames– avoid for intermediate cross frames– half-pipe stiffener provides a better alternative
15
![Page 16: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/16.jpg)
Results (cont.)
16
• Increased stability and safety of girders during all stages of construction.
• Better control of end twist during construction .• Serves as bearing stiffener.• Potentially eliminate first line of intermediate
cross frames near support.
Benefits of half-pipe stiffener:
![Page 17: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/17.jpg)
Results (cont.)
17
Design of half-pipe stiffener:
• Hand calculation method – determine modified effective length of girder for buckling calculations.
• UT Bridge softwareUpdated to incorporate the half-pipe stiffener
![Page 18: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/18.jpg)
Design of Half-Pipe StiffenerUT Bridge
18
![Page 19: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/19.jpg)
Results (cont.)
19
Consider use of staggered intermediate cross-frames in skewed bridges.
– Avoid congestion near supports– Better fatigue performance due to lower induced
live load force
Continuous:
Staggered:
![Page 20: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/20.jpg)
Improved Cross Frame DetailsTxDOT Project 0-6564Research In Progress
Graduate Research Assistants: Anthony Battistini, Wei Wang
Faculty Researchers:Todd Helwig, Michael Engelhardt, Karl Frank
TxDOT Project Director:Michelle Romage-Chambers
20
![Page 21: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/21.jpg)
Research Objective
21
Investigate behavior of TxDOT standard cross frames: • Stiffness• Strength• Fatigue
![Page 22: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/22.jpg)
Research Objective
22
Develop and evaluate potential improvements to cross frame details.
• Single diagonal cross frames• Use of tubular members• Use of double-angle members• Unconventional connection details
![Page 23: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/23.jpg)
Cross Frame Functions
• Critical for stability of steel bridges during construction
• Resist torsion in curved steel bridge systems
• Distribute lateral loadsand truck live loads
23
![Page 24: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/24.jpg)
Cross Frame Member and Connection Analysis
24
T-Stem Detail
Cast Connection Detail
Knife Plate Detail
Single Angle Detail
Double Angle Detail
![Page 25: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/25.jpg)
Component Stiffness, Strength and Fatigue
25
![Page 26: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/26.jpg)
Component Stiffness, Strength and Fatigue
26
![Page 27: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/27.jpg)
Cross Frame System Stiffness and Strength
27
![Page 28: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/28.jpg)
28
Cross Frame System Stiffness and Strength
![Page 29: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/29.jpg)
29
Cross Frame System Stiffness and Strength
![Page 30: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/30.jpg)
Cross Frame System Stiffness and Strength
30
![Page 31: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/31.jpg)
Key Observations from Research Completed To-Date
31
Standard TxDOT Single Angle Cross-Frame:• Behavior is complex due to use of single angle
members (unsymmetrical member, eccentric connections).
• Current methods used in design to calculate cross frame stiffness can lead to large errors.
• Fatigue behavior cannot be predicted by component level testing. Cross Frame fatigue behavior may be worse than previously assumed.
![Page 32: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/32.jpg)
Key Observations from Research Completed To-Date (cont.)
32
Promising approaches for improved cross frames:
• Single diagonal cross frame
• Tubular members or double angle members to minimize eccentric connections
• Knife plate connections for tubes
• Conventional gusset connections for double angles
![Page 33: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/33.jpg)
Strengthening Continuous Steel GirdersWith Post-Installed Shear Connectors
Graduate Research Assistants: Kerry Kreitman and Hemal Patel
Faculty Researchers:Michael Engelhardt. Todd Helwig, Richard Klingner,and Eric Williamson
TxDOT Project Director: Yuan Zhao
TxDOT Project 0-6719
Research In Progress
![Page 34: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/34.jpg)
Project Objective
Develop techniques to strengthen existing continuous multi-span non-composite steel girder bridges, through the use of post-installed shear connectors.
![Page 35: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/35.jpg)
0-4124: Methods to Develop Composite Action in Non-Composite Bridge Floor Systems(completed 2007)
5-4124: Implementation Project: Bridge Strengthening Through the Use of Post-installed Shear Connectors (completed 2009)
Project 0-6719 builds on previous TxDOT Projects:
![Page 36: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/36.jpg)
Key Concept:
Strengthen existing non-composite steel girder bridges….by developing composite action
![Page 37: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/37.jpg)
Older Non-composite Bridge
steel girder
concrete deckPost-installedshear connector
Focus of Project 0-4124: Increase positive moment capacity
![Page 38: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/38.jpg)
![Page 39: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/39.jpg)
Bridge Near Hondo, Texas:Improvement in Load Rating -
Load Rating
Inventory Level
Operating Level
Before Retrofit After Retrofit
HS 10.6
HS 17.6
HS 17.5
HS 29.1
Increase in load rating: 65 %
![Page 40: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/40.jpg)
Project 0-6719:
Extend concepts developed in 0-4124 and 5-4124:
Use post-installed shear connectors to strengthen continuous multi-span girders with inadequate flexural capacity in negative moment regions.
![Page 41: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/41.jpg)
![Page 42: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/42.jpg)
![Page 43: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/43.jpg)
Challenge:
Composite action is less efficient in negative moment regions – concrete is in tension.
Possible Approaches:
Use post-installed shear connectors in negative moment region- using reinforcing steel for composite action
Use post-installed shear connectors in positive moment region – allow redistribution of moment from negative to positive moment regions
![Page 44: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/44.jpg)
44
![Page 45: recent Research on Steel Bridges](https://reader034.fdocuments.us/reader034/viewer/2022051402/5695d3d81a28ab9b029f66f6/html5/thumbnails/45.jpg)
Recent Research on Steel Bridges- Closing Comments -
45
Overall Research Focus:
Improve safety and economy of new steel bridges.
Develop practical solutions to problems that arise in design and/or construction.
Develop methods to extend the life of existing steel bridges.