Memorial Bridge, Portsmouth, New Hampshire - Aaron Priest Photography

Night Timelapse Video

The Memorial Bridge on Route 1 crosses the Piscataqua River between Portsmouth, New Hampshire and Badger’s Island in Kittery, Maine. It is a through truss lift bridge with a 300 foot mid-span that can be raised to ~150 feet at mean high tide for large boats to pass underneath. The original bridge was built between 1920 and 1923 and was dedicated as a memorial to sailors and soldiers of New Hampshire who participated in World War I. In 2012, it was demolished and replaced with a new bridge of similar appearance over the next 18 months. However, the new bridge features several engineering advancements and was the first gussetless truss bridge in the world, also incorporating cold bending of steel and placing the machine rooms out of view underneath the bridge. The giant chains attached to the concrete counterweights in the towers are a dynamic counter balance to the 64 steel cables that raise the bridge. As the length and weight of the cables attached to the bridge increases and decreases during operation, the chain length and weight counterbalances. Each link on the giant chains weighs 170lbs! Former eight-term mayor of Portsmouth, Eileen Foley, who had cut the ribbon at the 1923 opening ceremony of the original bridge when she was 5, tied two ribbons together for the closing ceremony in 2011. In 2013, she again cut the red ribbon for the opening of the replacement bridge, 90 years after the original dedication.

The bridge is lit from the top down with 52-watt energy-saving color LED streetlights (red, green, magenta, and blue) that have sixteen programmed scenes, from solid and changing color scenes to a program that matches the tides with a gradual flow of light from the base of the towers to the top. The lighting design received input and advice from the International Dark-Sky Association to avoid excessive light pollution in the sky.

On March 29, 2015, I took a timelapse video of the bridge and the tide from Four Tree Island with Steff Rahaim. High tide was at 08:39 PM and low tide at 02:36 AM. One of the reasons we chose this night and location was to capture the tide going out with a 75% waxing gibbous moon at our back to light the foreground. The weather forecast was also supposed to be mostly clear until 3-4 AM and then heavily overcast by sunrise. We started shortly after sunset at 7:10 PM and shot until the batteries died at almost 5 AM with a Ramper Pro for the exposure ramping. The temperature got down to 20° F overnight and I used a dew heater on the lens, so the battery didn’t last until sunrise. An hour later I was driving home in a snowstorm anyway!

About 9:50 PM (00:21 seconds into the timelapse video), as we were eating pizza and chatting about photography, we were elated to see the bridge rise to almost full height for a large ship and a tugboat to pass through. A short while later it briefly raised again partway for the tugboat to return. Around 1 AM I recorded some ambient surround sound with a Zoom H2n audio recorder of the ducks, seagulls, and the background hum of the naval base and city (traffic and a dump truck that can be heard faintly). I don’t think Vimeo will play the surround sound though, only stereo.

The source footage is almost 8K at 7360 x 4912, 30fps, 12-bit CineForm 444. Contact me for commercial licensing.

Camera settings: 38mm, f/2.8, ISO 64 – 2000, 1/125 to 3 seconds (ISO & shutter ramped with a Ramper Pro), manual focus, manual white balance (ramped later via LRTimelapse), 15 second interval, 2,346 photos total.

Hardware used: Nikon D810, Nikon 24-70mm f/2.8, Ramper Pro, Goal Zero Sherpa 100, DewNet heater strip & Dew Buster controller, Really Right Stuff TVC-34L tripod, leveling base, and BH-40 ball head. 24-bit, 48kHz audio recorded with a Zoom H2n in 4 channel mode.

Software used: RAW conversion via Lightroom & LRTimelapse to 16-bit TIFFs, rendered to CineForm 444 with After Effects, surround audio mixed with Audition, and final export to 4K with H.264 compression for the web via Premiere Pro & Adobe Media Encoder.

More information on the Memorial Bridge:
http://memorialbridgeproject.com/
http://en.wikipedia.org/wiki/Memorial_Bridge_%28Portsmouth,_New_Hampshire%29
http://www.cmrp.com/blog/applications/the-first-gussetless-truss-bridge-in-the-world-ffox.html



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