The National Academies Press

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From page 136... ... 136 A p p e n d i x A As a result of the activities within Phase 1, several concepts were identified that merit research by others. This appendix summarizes the topics classified as Category 3 research topics and provides brief introductory comments for some of them. Read the entire page →
From page 137... ... 137 electrorheological fluids for vibration control of structures. According to Chong and Garboczi (2002) Read the entire page →
From page 139... ... 139 determine improvements in the microstructure that can lead to enhancements. Using Nanoparticles to Reduce the Permeability of Existing Concrete The second part of the study would involve the use of charged nanoparticles to reduce concrete permeability. Read the entire page →
From page 140... ... 140 and the thicknesses of the top and bottom plates are less than 0.25 in. The system offers the following advantages: • There is a significant increase of the load-resistance capacity of the deck. Read the entire page →
From page 141... ... 141 geometric specifications that can be changed in the orthotropic deck are total deck thickness, thickness of the plates (top, bottom, and ribs) , and spacing between the ribs. Read the entire page →
From page 142... ... 142 Table A.2. Modeled Structure's Responses Under Construction Maximum Deflection Maximum von Mises Stress Deck Direction Total Deck Thickness (in.) Read the entire page →
From page 143... ... 143 Figure A.9 shows an example of the deflections in the bridge due to the ultimate loading of the structure with two HS-20 trucks side by side. This is the final stage of the loading. Read the entire page →
From page 144... ... 144 Figure A.11. An example of the deflections in the bridge at the ultimate load. Read the entire page →
From page 145... ... 145 Figure A.12. Load–deflection curves of the structure associated with two trucks side by side. Read the entire page →
From page 146... ... 146 • An efficient spacing between the ribs of an orthotropic deck can be obtained from cost analysis. • Increasing the orthotropic deck plate thickness will increase the ultimate ductility of the bridge and, to a lesser extent, the ultimate load-carrying capacity of the bridge. Read the entire page →
From page 147... ... 147 Development of Seismic Details for Simple for Dead and Continuous for Live Load Steel Bridge System Recently a new steel bridge system, referred to as simple for dead load and continuous for live load, has gained popularity in nonseismic areas of the country. Research conducted over the past 10 years (Azizinamini 2013) Read the entire page →
From page 148... ... 148 Under longitudinal excitation, plastic hinges are located near the top and bottom of the columns; under transverse excitation, the plastic hinge is located near the bottom of the pier column. Seismic design of steel bridges is still a developing subject. Read the entire page →
From page 149... ... 149 The main challenge is to use the correct detail over the pier to connect the girder ends. Bottom flanges of steel embedded in the concrete diaphragm transmit large stresses to the concrete and, if not detailed correctly, can crush the concrete. Read the entire page →
From page 150... ... 150 Suggested Scope of Work An extensive amount of research data for the proposed system in nonseismic regions exists. However, there are specific requirements for seismic applications that need to be addressed. Read the entire page →
From page 151... ... 151 must be designed for maximum credible torsion and remain elastic. Several approaches can be used to ensure that the concrete diaphragm remains elastic under maximum credible torsion. Read the entire page →
From page 152... ... 152 Figure A.28. Typical finite element models used to investigate force transfer mechanism for nonseismic details. Read the entire page →
From page 153... ... 153 Table A.3. Additional List of Category 3 Research Items Research Area Topic Fatigue and fracture Develop guide for fatigue retrofitting. Read the entire page →

From page 136...

... 136 A p p e n d i x A As a result of the activities within Phase 1, several concepts were identified that merit research by others. This appendix summarizes the topics classified as Category 3 research topics and provides brief introductory comments for some of them.