Structural Health Monitoring and Condition Assessment of Chulitna River Bridge

INE/AUTC 12.29 (Training Report) and INE/AUTC 12.30 (Sensor Selection and Field Installation Report

Smart FRP Composite Sandwich Bridge Decks in Cold Regions

INE/AUTC 12.0

Life Cycle Costs for Alaska Bridges

INE/AUTC 15.0

Seasonally Frozen Soil Effects on the Seismic Performance of Highway Bridges

INE/AUTC 12.0

Phase II: Chulitna River Bridge Structurally Health Monitoring

This study is phase 2 of a two phase research project. In Phase 1 a structural health monitoring system (SHMS) was installed on the Chulitna River Bridge. This bridge is 790 feet long, 42 foot 2 inches wide and has 5 spans. As part of that effort, three loaded dump trucks were used to conduct seventeen static and dynamic loadings on the structure. In addition to studying the bridge using SHMS, two ambient free vibration tests were conducted a year apart by. In 1993, the deck on this 1970 five span bridge was widened from 34-feet to a 42 foot 2 inch concrete deck. Increased load was accounted for by strengthening two variable depth exterior girders and converting interior stringers to interior truss girders. Construction documents for the upgrade called for stage construction. At the time of this study, the bridge had five bearings that were not in contact with the superstructure. Feasibility of using Structural Health Monitoring Systems (SHMS) for Alaska Highway Bridges was examined. Also, SHMS data for the load tests of Phase 1 were used to calibrate a three-dimensional model (FEM) to predict response and conduct a 2014 Operating Load Rating.LIST OF FIGURES ....................................................................................................................... iv LIST OF TABLES ........................................................................................................................ vii DISCLAIMER .............................................................................................................................. ix EXECUTIVE SUMMARY............................................................................................................. 1 CHAPTER 1.0 INTRODUCTION................................................................................................. 3 1.1 History .............................................................................................................................. 3 1.2 Bridge Details ................................................................................................................... 3 1.3 Phase 1 Research Study.................................................................................................... 5 1.4 Phase 2 Research Study.................................................................................................... 5 CHAPTER 2.0 LOAD RATING.................................................................................................... 7 2.1 General ............................................................................................................................. 7 2.2 Operating Load Rating ................................................................................................... 10 2.2.1 Investigation with updated calibrated finite element model, FEM (as-is condition) ............................................................................................................................. 11 2.2.2 Model 1 – Four members (A, B, C, and D) removed ............................................. 11 2.2.3 Model 2 – Five members (A, B, C, D, and E) removed ......................................... 11 2.2.4 Other alternative operating load ratings. ................................................................. 12 CHAPTER 3.0 CALIBRATED FINITE ELEMENT MODEL ................................................... 32 CHAPTER 4.0 PROPOSED ALASKA BRIDGE MONITORING SYSTEM ............................ 34 4.1 General ........................................................................................................................... 34 4.2 Selecting SHMS for Alaska ........................................................................................... 35 4.3 New Bridges (Proposed Monitoring Systems) ............................................................... 36 4.4 Existing Bridges (Proposed Monitoring Systems) ......................................................... 36 4.5 All Bridges (Proposed Monitoring Systems) ................................................................. 36 CHAPTER 5.0 CONCLUSIONS................................................................................................. 39 5.1 Phase 1 (Previous Study)................................................................................................ 39 5.1.1 Gravity load testing ................................................................................................. 39 5.1.2 Ambient testing (2012 tests were Phase 1; 2013 tests were Phase 2) ..................... 40 5.2 Phase 2 (Current Study) ................................................................................................. 40 5.2.1 Outcome 1 – Finite element model ......................................................................... 41 5.2.2 Outcome 2 – Structural evaluation and load rating ................................................ 41 5.2.3 Outcome 3 – LRFR HL-93 live load stresses for the critical members .................. 41 APPENDIX A – SIMPLE ACCURACY TEST............................................................................ 44 APPENDIX B – LONGITUDINAL BEHAVIOR TEST ............................................................. 47 APPENDIX C – MODEL IMPROVEMENTS (LONGITUDINAL DIRECTION) .................... 50 APPENDIX D – TRANSVERSE BEHAVIOR PRIOR TO MODEL MODIFICATIONS.......... 52 APPENDIX E – MODEL IMPROVEMENTS (TRANSVERSE DIRECTION)......................... 57 APPENDIX F – CORRELATION BETWEEN CALIBRATED MODEL AND EXPERIMENTAL DATA............................................................................................................. 61 APPENDIX G – CALIBRATED FINITE ELEMENT MODEL ................................................. 63 APPENDIX H – SENSOR LAYOUT .......................................................................................... 66 APPENDIX I – LOAD TESTING................................................................................................ 69 APPENDIX J – A FUTURISTIC APPROACH TO CALIBRATING A FINITE ELEMENT MODEL ........................................................................................................................................ 8

The plastic behavior of reinforced concrete beams with varying percentages of reinforcing steel symmetrically placed

The purpose of this study is to determine the limitations of the plastic behavior of reinforced concrete beams with varying percentages of high strength steel (ASTM-A-432) cutoff in the compression region d distance beyond the point of inflection. Comparison was made with the derived equations. Steel was placed symmetrically in order to obtain like action at critical sections. The members tested were of a propped beam nature having a total clear span of 5\u276 with a 6 overhang on one end and 1\u276 overhang on the other. Concentrated loads were applied so as to obtain midspan loading and fixed end conditions at only one end. Beam sections were 3 X 6 with a 5 ¼ depth to steel. Reinforcing cover requirements were not met (American Concrete Institute) due to the limited size of sections. Shear reinforcing consisted of closed loop stirrups made from no. 9 gage wire. Electric Sr-4 strain gages were applied to the steel and concrete at all critical sections in order to obtain moment-curvature relationships. Dial gages were used to obtain the deflection at midspan. Of the eight speciments tested, three had shear-bond failures at or near the point of inflection, thus limiting the plastic design theory for reinforcing that is symmetrically placed in beams of this kind. The moment and load deflection curves compared favorably with theory except for the high percentages of steel --Abstract, page ii