Bridge Stats

  • Mile: 12.7
  • Opened: May 24, 1958, 1905, 1887
  • Type: Double-leaf Chicago-type, fixed trunnion, Bascule
  • Engineers/Designers: Sverdrup & Parcel (MO),Moffatt, Nichol & Taylor of Portland
  • Owner: Multnomah County
  • Total Length: 760’ (deck truss not approaches)
  • Main Span Length: 284’ 5”
  • Counterweights: 2 Counterweights @ 950 tons each (1,900,000 pounds)
  • GPS Coordinates: 45.517810, -122.669584

The Morrison Bridge

 The Morrison Lights of WLB’s Lighting Partner program are frequently featured on KGW News Channel

Become a Morrison Bridge Lighting Partner

ABOUT THE MORRISON

The Morrison was Portland’s  first bridge and it  operated as a toll bridge.  The current  design is the third bridge at this location.  Both of  the previous structures (1887 and 1905) were swing spans; this last moveable bridge built on the  Willamette in Portland has bascule spans which can be tilted up.  Design work for the six-lane, three-span, steel deck truss structure  began in 1928.   It was built for $12,841,256 and opened  in 1958.   Like Morrison St., the bridge was named  for a Methodist missionary from Scotland who built the  first house on that thoroughfare.

The Morrison is structurally like the Burnside, but without ornamentation in its railing or its pair of bridge houses (also mounted on the south  face).  It serves as a major travel corridor link  between SE Portland and inner-city Portland and to  Interstate 5.

When river traffic requires that the bridge open, a controller inside the western bridge  house operates a below-deck rack and pinion system and gears 36  feet tall.  That system lifts and returns the Morrison’s double-leaf bascule spans (each 150 feet long) by means of counterweights, one set for each side.  The roadway’s open metal  grating was replaced with fiberglass in 2011-12 to further reduce its weight, but hundreds of tons of counterweights are still required to balance the bascule halves.

 

THE ARCHITECTURAL LIGHTS

The first lighting system, designed by PAE Engineering and installed in December of 1987, consisted of  16 white floodlights fixed to the north and south piers many feet below the deck.  To add color a theatrical gel was placed in a filter attached to each fixture.  The bulbs and the gels were short-lived.  Each replacement was risky and expensive because it required suspending a worker below deck, with tools and supplies, to hang while tending each fixture.

As lighting technology advanced Ed  Slavin of Northern Illumination  Company led WLB’s efforts to  upgrade that first system.  Now 32 UHB (Ultra High Brightness) LED (Light Emitting Diodes) fixtures vastly reduce energy use and maintenance costs.  They use 1/8 the energy of the floodlights.  The bulbs should last about 25 years (run an average of 8 hours/day).  The fixtures have been hung on brackets designed by the Multnomah County Bridge Shop which allow them to be swung up onto the bridge deck for maintenance.  Also, these LEDs can be reprogrammed for a wide range of  colors and timing patterns from a Bridge Shop computer keyboard, further reducing labor to a minimum.

Cost of the  fixtures and labor to install the 1987 system were donated by the International Brotherhood of Electrical Workers and the  National Electrical Contractors Association.  An anonymous donation on behalf of WLB volunteers launched  the  upgrade efforts.  Although the LEDs were costly, their energy efficiency and WLB’s purchase of alternative energy for all its lighting systems so pleased Pacific Power that it donated $50,000 to complete the project.  Pacific Power also hosted the LED “lights-on” party on February 14, 2007.

 

COMMUNITY PARTICIPATION

WLB felt that the ease of computerized timing and color changes made it feasible to involve the public in choosing lighting designs for the Morrison.  Commissioner Deborah Kafoury and her chief of staff Beckie Lee championed the Lighting Partner program to do just that.  It is administered by WLB.