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

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

Life Cycle Costs for Alaska Bridges

INE/AUTC 15.0

Smart FRP Composite Sandwich Bridge Decks in Cold Regions

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

Seasonally Frozen Soil Effects on the Seismic Performance of Highway Bridges

INE/AUTC 12.0

Phase II: Correlation Between Experimental and Finite Element Analysis

In this study, we will monitor the behavior of the Alaska Chulitna Bridge for the specific purpose of assisting the DOT in performing an accurate condition assessment of this bridge. Based on the state-of-the-art SHM knowledge and technologies with a specific interest in those which could be used on bridges in cold, remote regions, the objective of this study is to provide important information for structural condition assessment of the Chulitna River Bridge. Proposed SHM objectives are listed below—applicable to all bridges: Develop a SHM protocol including preferred system integrator, software, instrumentation, and sensors suitable for Alaska’s remote, harsh weather locations. Develop criteria to incorporate SHM into the state’s bridge management process. The established SHM system for ADOT&PF will be able to monitor performance of bridges subjected to extreme temperature and conditions—an aspect that is very important information for assessment of the structural condition and potential remaining service life of Alaska bridges.Pacific Northwest Transportation Consortium Alaska Department of Transportation & Public Facilitie

Quarterly Report 2: Progress on Evaluation of WTC7 Collapse

List of Figures ii Introduction 1 Part A 1 SAP2000 Modeling of WTC7 1 Summary of NIST Report Findings on Column 79 of Floor 13 4 Literature Review on Fire Modeling in Structural Analysis 4 Proposed Work for the Third and Fourth Quarters 20 References 21 Part B 22 WTC7 Progressive Collapse Study 22 WTC7 Nonlinear Connection Study 25 WTC7 Connection Modeling Using Abaqus 27 WTC7 Connection Analysis Using Abaqus 31 Current Research Plan 34 References 3