This research is aimed at developing a preliminary methodology for determining replacement priorities for in-service WSDOT luminaire and traffic signal poles. Furthermore, the research will identify critical WSDOT details for which experimental data are not available in the literature, and will begin development of a reliability-based methodology for estimating the remaining life of such structures. Recommendations for additional research, including field and laboratory testing as well as analytical modeling and methodology development, will be made on the basis of the findings of this preliminary study. Additionally, recommendations will be made regarding the types of damage to look for when inspecting poles to determine whether they need replacement.
The specific research products will be as follows:
· a preliminary ranking of poles likely to be susceptible to fatigue failure based on existing experimental data and a parametric study of typical WSDOT pole configurations using the AASHTO fatigue design loads
· a database of tested and classified fatigue critical pole details based on existing experimental data
· a preliminary framework for a reliability-based assessment of the remaining fatigue life of traffic signal and luminaire pole structures in Washington State
· recommendations regarding in-service pole inspection
· recommendations regarding additional research.

This project received matching funds from TransNow that are still being spent. Those funds had expanded the scope of the project to include fatigue testing of selected luminaries. We are nearing the end of that testing. We have completed an extensive literature review on the fatigue life of luminaires. We have also developed a preliminary framework for probabilistic analysis of the remaining life of luminaires and traffic signal poles. Current activities that include: Completion of the fatigue testing (will be done in 1 week), data analysis (ongoing), drafting of the final report (ongoing). Draft report submission is expected by September 1st.

Testing: We have completed testing of the first luminaire and expect to done with the second luminaire test by the end of the week. The first luminaire demonstrated a remaining fatigue life that exceeded its virgin design life with failure occurring around the hand hole. Possible explanations for the long life include: (a) the pole was not subjected to large wind induced fatigue loads in the field (it may have been sheltered or was just in a low wind zone) (b) the details for this pole are robust and exceed the fatigue life assigned to their category by AASHTO (there is significant randomness in the fatigue life of details and considerable differences within a particular AASHTO detail class) (c) some particular features of this pole design helped to provide and increased fatigue life (thick base plate, anchor bolts positioned close to the pole, thick welds). Should the second pole results confirm this log life it would be fairly clear that this particular pole type with these details is not in need of immediate replacement.

Analysis: Since the failure occurred at the hand hole rather than the base plate as expected, we are conducted an advanced finite element analysis to estimate the stress distribution in the pole. Preliminary results indicate that despite what design calculations indicate, the location of peak stress is indeed at the hand hole.

Literature Review: The write-up of the comprehensive literature review is mostly complete (revisions are underway and took a back seat to testing). We have found some interesting information that will be used to make some inspection recommendations, including: (a) checking anchor bolt tightness, (b) checking anchor bolt corrosion, (c) checking for cracking at base plate welds and hand hole welds. These recommendations should be easily employed by WSDOT employees in the field.

Remaining Life Estimation: There is tremendous uncertainty in the remaining life of poles due to: (a) the uncertainty in the actual wind loads that the poles have been subjected to and (b) the uncertainty in the actual life of specific pole details. To estimate remaining life a framework that treats this uncertainty is necessary. The results of the implementation of such a framework would be: there is a 90% chance that a particular pole has a remaining life of less than 5 years. The final report will contain an outline of such a framework and will identify what is needed to develop it: (a) wind velocity data from around the state, (b) virgin fatigue life data for pole details of interest, (c) analytical models of various poles (luminaires and traffic signal poles), and (d) validation through field and laboratory testing.

Matt brought up the idea of looking at the dynamic response of poles and using changes in their fundamental frequency to identify problems. This could be useful for certain types of damage that involve slow degradation, such as corrosion. However, as some literature has noted, fatigue failure is generally quite fast. At one instant the pole is behaving as though undamaged and then suddenly a crack forms and quickly propagates. Thus, this problem is not likely to be a successful possible application for frequency monitoring. That said, I will be sure some discussion of this is included in the report.

No new activities are proposed.

No problems have been identified.

Recommendations for implementation of the research results will be included in the final report.