WSDOT SR520 PROGRAM Pontoon Construction Project Expert Panel Report, Phase 2 Submitted to WSDOT by the Expert Panel February 18th 2013 . THE SR520 EXPERT REVIEW PANEL: Chair: John Reilly, Panel: Dr. Neil Hawkins, Dr. John Clark Mr. Tom Sherman, Mr. Mark Leonard Mr. Stephen Tatro Panel Members’ – Background (for details, See Appendix E) The Expert Panel members were selected for their expertise in the design and construction of complex concrete and pre-stressed/post-tensioned1 concrete structures. More than one member was required to have experience in floating bridges. An understanding of concrete materials and technologies was required. Current Expert Panel members are: Dr. Neil M. Hawkins, Ph.D., Dist. M. ASCE, Hon. M. ACI, Professor Emeritus, University of Illinois, and former chair of the Civil Engineering Department, University of Washington, specialist in reinforced and prestressed concrete. Dr. John H. Clark, P.E., Ph. D., a consultant for the design and construction of long-span bridges and heavy structures, including pre-stressed concrete. Mr. Tom Sherman, specialist in floating bridge design and construction, TES Enterprises Mr. Mark Leonard, FHWA Resource Center, former Bridge Engineer for the Colorado Department of Transportation. Mr. Stephen B. Tatro, consultant specializing in evaluation, testing, design, and construction of concrete structures and materials. The panel is chaired by Mr. John Reilly, P.E., C.P. Eng., with experience in major project management, contracting and delivery, risk assessment / mitigation and prestressed concrete design. Summary resumes of the Panel members can be found in Appendix E 1 Prestressing refers to beneficial stressing of the concrete structures before application of in-service loads. Post-tensioning is the process of applying that prestressing after the concrete has been placed and hardened. SR520 PCP Expert Review Panel Report Page 2 of 68 Submitted to WSDOT February 18th, 2013 Expert Review Panel, Phase 2 Report, SR520 Pontoon Construction Project Table of Contents THE SR520 EXPERT REVIEW PANEL:................................................................................................................................2 Panel Members’ – Background (for details, See Appendix E).....................................................................................2 1. SUMMARY................................................................................................................................................................6 KEY FINDINGS, CONCLUSIONS AND RECOMMENDATIONS ..................................................................................................6 1. Structural sufficiency/watertightness......................................................................................................................6 Bolt-beam stresses and cracking ................................................................................................................................................ 6 Findings...................................................................................................................................................................................... 7 End-wall cracking ...................................................................................................................................................................... 7 Finding ....................................................................................................................................................................................... 8 2. Quality of the as-constructed pontoons...................................................................................................................8 3. Crack repair and minimization – methods and strategies ......................................................................................9 Non post-tensioning cracking - keel and deck slabs, walls, interior precast elements................................................................ 9 Post-tensioning related cracking - bolt-beams, end walls........................................................................................................... 9 Repair methods......................................................................................................................................................................... 10 Crack reduction, concrete mixing and placement..................................................................................................................... 10 Concrete Water Cement Ratio.................................................................................................................................................. 10 Thermal Control....................................................................................................................................................................... 10 Time-dependent effects – current contract requirement ........................................................................................................... 10 Crack reduction, bolt-beams and end walls.............................................................................................................................. 11 4. Maintenance considerations .................................................................................................................................11 2. INTRODUCTION ...................................................................................................................................................12 Introduction ...............................................................................................................................................................12 WSDOT Strategy, Emergency Replacement, Contract costs, As-bid Savings............................................................12 Timeline, unexpected cracking...................................................................................................................................12 ERP Scope - Phase 1 .................................................................................................................................................13 Results of the ERP Phase 1 work...............................................................................................................................13 ERP work continued, Phase 2....................................................................................................................................13 ERP Scope - Phase 2 .................................................................................................................................................13 This report .................................................................................................................................................................13 ERP technical assistance ...........................................................................................................................................14 3. REVIEW AND ASSESSMENT OF THE PONTOONS’ STRUCTURAL SUFFICIENCY.............................14 SCOPE FOR THIS SECTION OF THE REPORT .......................................................................................................................14 Review of Glosten report on wind and wave forces...................................................................................................14 Finding ..................................................................................................................................................................................... 15 Review of Design Criteria..........................................................................................................................................15 Service and Ultimate Load Cases............................................................................................................................................. 16 Crack Widths............................................................................................................................................................................ 16 Table 2, Summary of Relevant Crack Width Criteria............................................................................................................... 16 Findings.................................................................................................................................................................................... 17 Review of Calculation Notebooks ..............................................................................................................................17 Load Cases, Strain Compatibility and Prestress level...............................................................................................17 Findings.................................................................................................................................................................................... 18 DEMAND / CAPACITY RATIO ...........................................................................................................................................18 Finding ..................................................................................................................................................................................... 18 INDEPENDENT STRUCTURAL SUFFICIENCY ANALYSIS (PB) ............................................................................................18 Recommendation.....................................................................................................................................................................