The proposed research project will conduct field testing of an innovative signal head vibration mitigation device called the signal head vibration absorber (SHVA) to reduce fatigue in traffic signal support structures that experience excessive wind-induced vibration. The SHVA uses the mass of the signal head as the mass of the vibration absorber and connects the signal head to the mast arm using a linear spring and eddy current damper to reduce unwanted vertical vibrations in traffic signal mast arms. This configuration is low cost, maintenance-free and rugged. The SHVA requires no external power or sensors for operation and is fully compatible to typical existing signal heads. This novel SHVA concept has been tested in a full-scale laboratory experiment, in a project sponsored by the NCHRP-IDEA program (Project Number 141); where it has been shown to increase the damping in a 35-foot mast arm and pole from 0.15% of critical damping to over 10% of critical damping. This corresponds to a reduction in the steady state vibration of the mast arm by a factor of 80 and a reduction in the vibration of the signal head itself by a factor of 60 over the typical rigidly-connected system. The NCHRP-IDEA Project Number 141 final report was published and is available online at: http://onlinepubs.trb.org/onlinepubs/idea/finalreports/highway/NCHRP141_Final_Report.pdf. Furthermore, at the request of the AASHTO’s Standing Committee on Research (SCOR), the NCHRP-IDEA Program Committee Chair, Ms. Sandra Larson, made a presentation at its December 2010 meeting on the program’s accomplishments; NCHRP-IDEA Project Number 141 was highlighted as an example of an NCHRP-IDEA success in Ms. Larson’s presentation. Also, NCHRP-IDEA Project Number 141 was identified as an IDEA product with a high near-term implementation/commercialization potential in the following document available online at: http://onlinepubs.trb.org/Onlinepubs/IDEA/SuccessStories/IDEAProductsTables.pdf The Connecticut Department of Transportation has posted a streaming video documenting the laboratory results of the NCHRP-IDEA project at: mms://159.247.0.209/mediapoint/Uconn/NCHRP_Idea_141_v4.wmv Significant progress was made under the concept exploration funding of NCHRP-IDEA. Based on the success of the laboratory testing, a series of field tests will be conducted within this project to demonstrate the performance on traffic signal structures located in the field. All States involved in the project will have a representative on the project’s Technical Advisory Committee (TAC). States will have the option to participate at the equipment level, where SHVAs are installed on a traffic signal support structure in the participating State. The proposed vibration mitigation device can reduce the wind-induced vibrations of traffic signal structures, reducing fatigue, increasing the safe life of the structure, and saving money. The SHVA can potentially change the way vibration in transportation structures are mitigated.

The objective of this project is to: 1.) conduct field tests to assess the performance of signal head vibration absorbers (SHVAs) on various signal support structure and signal head configurations; and, 2.) educate signal support structure owners to evaluate effective vibration mitigation devices for their infrastructure. Each field deployment will include SHVAs applied to a mast arm to reduce wind induced vibration. The traffic signal structures will be evaluated with strain transducers and accelerometers to assess the performance. The SHVAs can be engaged and disengaged such that uncontrolled and controlled data can be taken: (i) when the system is first installed; and, (ii) at a time approximately 12 months after the installation. For each signal support structure tested, the reduction in stress range the SHVA can affect will be evaluated and reported to the Department of Transportation. Another objective is to provide signal support structure owners with the necessary tools to identify effective vibration mitigation devices for their specific traffic signal support structure inventory.

The objective of this project is to: 1.) conduct field tests to assess the performance of signal head vibration absorbers (SHVAs) on various signal support structure and signal head configurations; and, 2.) educate signal support structure owners to evaluate effective vibration mitigation devices for their infrastructure. Each field deployment will include SHVAs applied to a mast arm to reduce wind induced vibration. The traffic signal structures will be evaluated with strain transducers and accelerometers to assess the performance. The SHVAs can be engaged and disengaged such that uncontrolled and controlled data can be taken: (i) when the system is first installed; and, (ii) at a time approximately 12 months after the installation. For each signal support structure tested, the reduction in stress range the SHVA can affect will be evaluated and reported to the Department of Transportation. Another objective is to provide signal support structure owners with the necessary tools to identify effective vibration mitigation devices for their specific traffic signal support structure inventory.

UPDATED 4/9/12 – Cost information was updated. UPDATED 2/17/12 - The request for FHWA approval to establish a transportation pooled fund (TPF) study using 100 percent (100%) SPR funding was forwarded to FHWA on 2/17/12. Cost Information The proposal assumes that six (6) States will participate in the project at the equipment level, and so, the cost of the project would be $66,001 in the first year and $74,999 in the second year, for a total cost of $141,000. The cost per State, with six (6) States participating in the project at the equipment level, would be $11,000 for the first year and $12,500 for the second year. This cost could increase if the State would like a more extensive deployment than two SHVAs attached on a single mast arm. The research team can discuss options and costs for different implementations. The project will supply the SHVA equipment (purchased from Vibration Mitigation Technologies) and technical support for the deployment in the field, but each State is responsible for supplying the signal head, lights, etc. and installation costs either using their own forces or contractors. The research team will install the needed instrumentation and SHVA when we are there for the installation. The research team will also assist in estimating travel costs for the State’s TAC member to attend the project meetings. These TAC member travel costs can be added to the State's contribution, if desired. The first year funding is requested in Federal Fiscal Year 12 to allow suffficient time for the funds to be transferred so the contract can be put in place by the anticipated start date of April 2013.