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Alternative Development |
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From January to May, 2007 the Sellwood Bridge team (including the Community Task Force
and the Policy Advisory Group) developed preliminary concepts, added additional
concepts suggested by the public, reviewed concepts to make sure they met the minimum requirements for the project, eliminated concepts,
and selected a broad range of alternatives
for further evaluation.
In October 2007, the Policy Advisory Group (PAG) approved five alternatives to be studied in the draft environmental
impact statement (draft EIS). After the draft EIS is completed, the preferred alternative will be chosen.
Like a puzzle, alternatives being considered have three parts that need to fit together: the
alignment, the interchange, and the
cross-section. More information is provided below.
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Click on the colors below the map to learn more about each alignment.
This alignment, which was suggested by the public, begins at Tacoma Street and 6th Avenue on the east, swings north of the existing bridge alignment on both the
east and west sides of the river, (on the east side to avoid impacts to residential and commercial properties and
on the west side to avoid impacts to park properties). The west bank landing is north of the existing bridge. The existing bridge will be used
for crossing the river while the new bridge is built.
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Click on the picture below to see a larger PDF version.
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Teal Alignment
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This alignment, which was suggested by the public, begins at Tacoma Street and 6th Avenue on the east, swings north of existing alignment on the east side to
avoid right-of-way impacts to residential properties. The west bank landing is just north of the existing
bridge. The existing bridge will be used for crossing the river
while the new bridge is built.
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Click on the picture below to see a larger PDF version. |
Pink Alignment |
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This alignment begins at Tacoma Street and 6th Avenue on the east, just north of
the existing bridge alignment, with the west
bank landing at approximately the same location as the existing interchange. The existing bridge will be used for crossing the river while the new
bridge is built.
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Click on the picture below to see a larger PDF version. |
Blue Alignment |
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There are two Yellow alignments. Yellow Center uses the existing bridge alignment; beginning at Tacoma Street
and 6th Avenue on the east and the west bank landing at approximately the same location as the existing interchange.
Yellow South uses the existing bridge alignment plus the area immediately adjacent to the south.
The Yellow Center can be used for both bridge rehabilitation and replacement alternatives. Yellow South is for
replacement alternatives only. Bridge rehabilitation alternatives include several variables: adding a detour bridge
during construction and providing additional protection against loss of life and property in an earthquake
(Phase II seismic retrofit).
- Seismic Retrofit: New bridges must be designed to remain in service during and after
moderate earthquakes and to be able to withstand large earthquakes without collapsing. Older bridges can be
retrofitted to resist earthquakes. Phase I retrofits are a low cost option aimed at keeping bridge beams from
falling off their supports; all of the Sellwood Bridge rehabilitation alternatives include this treatment.
Phase II retrofits are much more costly. They are intended to preserve the structure and protect the investment
from total collapse; this usually involves strengthening of the piers and foundations. Phase II retrofit of the
existing Sellwood Bridge is estimated at $28,125,000 in 2012 dollars. No bridge crossing the Willamette River
in Portland has received a Phase II retrofit due to lack of funding. Phase II retrofit is an option that can be
considered on all of the Sellwood Bridge rehabilitation alternatives. Any new bridge would exceed Phase II retrofit
capability for protection of life and property in an earthquake.
- Detour Bridge: Rehabilitation of the existing Sellwood Bridge would require closing the bridge
to traffic throughout the construction period, likely to extend about three years. During that time, vehicles can
use other bridges in the Portland area to move across the river. Maintaining a river crossing in the Sellwood area
during rehabilitation can be accomplished with a detour bridge at an approximate cost of $35,600,000 in 2012 dollars.
For planning purposes, the Teal alignment was selected for the detour bridge to minimize residential and business
relocations. A temporary ferry option could also be considered.
Bridge replacement in the Yellow South alignment includes the option to use the existing bridge truss (steel structure supporting the bridge) in a double truss new bridge. This idea is explained below.
- Double Truss: The existing truss (steel structure supporting the bridge) is reused in all
of the bridge rehabilitation alternatives. It is also possible to reuse the existing truss in a “double truss”
bridge replacement alternative. In this option, a new truss is placed along side the existing truss. This adds
strength and allows for a wider bridge. Despite reuse of the existing truss, the “double truss” alternative is
categorized as a bridge replacement rather than a rehabilitation because approximately 75 percent of the structure
is new.
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Click on the picture below to see a larger PDF version. |
Yellow Alignment |
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Begins at Tacoma Street and 6th Avenue on the east, this alignment is located south of the existing bridge alignment
with the west bank landing located south of the existing interchange. The existing bridge will be used for crossing the river
while the new bridge is built.
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Click on the picture below to see a larger PDF version. |
Purple Alignment |
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Several alignments have been eliminated from further study. Click on the colors below to learn more.
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This alignment, which was suggested by the public, begins at Tacoma Street and 6th Avenue on the east, extends north along Oaks Park
Way, crossing through the Sellwood Riverfront Park to connect with Taylor's Ferry
Road on the west.
This alignment is significantly longer than all others; leading to a significantly higher cost.
The alignment runs along Sellwood Riverfront Park and as a result, has greater impacts on
this park than any other alignment. The alignment provides a direct connection between
Taylor’s Ferry Road and Tacoma Street, which could encourage an undesirable increase in traffic to the
corridor.
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Click on the picture below to see a larger PDF version. |
Detail of Gold Alignment |
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Begins at Tacoma Street and 6th Avenue on the east, extends north along Spokane Street, and connects to
Highway 43 on the west, north of the existing bridge.
Removed from consideration because it was similar to the Teal alignment, but with higher residential and commercial impacts.
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Click on the pictures below to see larger PDF versions. |
Non-Signalized Intersection |
Signalized Intersection |
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Begins at Tacoma Street and 6th Avenue on the east, extends north along Spokane Street, and connects to Highway
43 on the west near the existing bridge location.
Removed from consideration because it was similar to the Pink alignment, but with higher residential impacts.
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Click on the pictures below to see larger PDF versions. |
Non-Signalized Intersection |
Signalized Intersection |
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The northern yellow alignment was similar to the Blue alignment, with no net advantages, so it was eliminated from further study.
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Click on the picture below to see a larger PDF version. |
Signalized Intersection |
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This alignment, which was suggested by the public, begins at Tacoma Street and 6th Avenue on the east, extends south along Umatilla
Street, and connects to Highway 43 on the west, south of the existing bridge and
Powers Marine Park.
This alignment spares some right-of-way impacts while increasing others with no net advantage.
The alignment creates out-of-direction travel for most bridge users and is somewhat higher
in cost because of its longer length.
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Click on the picture below to see a larger PDF version. |
Signalized Intersection |
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This alignment, which was suggested by the public, begins at Tacoma Street and 16th Avenue on the east and connects to Taylors Ferry Road on the west.
This concept was eliminated because it serves primarily through traffic, leaving local traffic
with significant out-of-direction travel, particularly for neighborhood destinations. The
length and access points also restrict a tunnel’s usefulness for emergency vehicles, which
need immediate access to local destinations. In addition, the cost of the tunnel option is
significantly greater than the bridge options. Cost estimates derived from construction costs
of the Eastside Big Pipe Project (Combined Sewer Overflow Program) suggest tunnel costs
at five times of a bridge option of the same capacity. Right-of-way costs are not likely to be
less, and the continuing operating costs would be greater. Accommodation of bicycle and
pedestrian facilities represents an additional cost, requiring either rehabilitation of the
existing bridge and ongoing costs of maintenance, or construction of a new bike and
pedestrian facility across the river.
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Click on the picture below to see a larger PDF version. |
Tunnel Alignment
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Click on the picture below to look at the tunnel alignment crossview and required depths. |
Tunnel Crossview
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Two interchanges are under consideration: a signalized interchange and a roundabout. Both have two levels like the existing interchange,
with Highway 43 running smoothly beneath the bridge exit and entrance ramps. Either interchange can be used with all of the alignments
and both replacement and rehabilitation alternatives.
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Signalized Interchange
The signalized interchange allows traffic (vehicles, bicyclists and pedestrians) to get on and off the bridge through a single traffic signalized intersection above Highway 43. Bicyclists and pedestrians would use switchback ramps and signalized crosswalks to access west side destinations.
Click on the picture below to see a larger PDF version.
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Roundabout Interchange
This roundabout allows traffic (vehicles, bicyclists and pedestrians) to get on and off the bridge in a continuous flow by
circulating through a roundabout above Highway 43. Bicyclists and pedestrians would use switchback ramps to access
recreational trails on the west side. No signalized crosswalks would be provided on the roundabout.
Click on the picture below to see a larger PDF version.
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Many interchange options have been eliminated from further study.
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Read about the cross-sections by clicking on the words below. Each width can be used in comination with several alignments.
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Rehabilitation options |
A (2-lane, 1-level, 53 feet wide)
This single level, 53-foot cross-section provides two 14-foot travel lanes and adds 10-foot shared bicycle/pedestrian paths on each side.
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I (2-lane, 2-level, 31 feet wide)
This is the current width of the Sellwood Bridge. In this 31-foot width cross-section, a 14-foot shared use path would be placed underneath the bridge deck which would have two 14-foot vehicle lanes. This cross-section would only
be used with a rehabilitation concept on the Yellow alignment.
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L (2-lane, 1-level, 57 feet wide)
This single-level cross-section provides two 11-foot travel lanes, two 5-foot shoulders/bike lanes, and two 10-foot shared bicycle/pedestrian paths on each side of the bridge (total width of 57 feet). A 57-foot bridge width is about the same width as the Broadway Bridge. This cross-section would only
be used with a rehabilitation concept on the yellow alignment.
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Replacement options |
A' (2-lane, 53-feet wide)
A new bridge with two 14-foot lanes and two 10-foot sidewalks (total width of 53 feet) on any of the alignments. This cross-section can be used with all the alignments.
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C (2-lane, 64 feet wide)
A single-level bridge replacement with two 12-foot travel lanes, two 6.5-foot bike lanes, and two 12-foot sidewalks.
A 64-foot bridge width is about the same width as the Broadway Bridge. This cross-section can be used with all the
alignments recommended for advancement.
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C' (2-lane, 68 feet wide)
A single-level bridge replacement with two 12-foot travel lanes, two 6.5-foot bike lanes, one 20-foot shared path,
and one 8-foot sidewalk. A 68-foot bridge width is about the same width as the Broadway Bridge. This cross-section
can be used with all the alignments.
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D (2 auto/truck lanes, 2 transit-only lanes, 75 feet wide)
A single-level bridge replacement with two 12-foot vehicle lanes, two 12-foot transit lanes, one 16-foot shared use
path, and one 8-foot sidewalk. A 75-foot wide bridge is about the same width as the Burnside Bridge. This cross-section
can be used with all the alignments.
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E (4-lane, 77 feet wide)
A single-level bridge replacement with four 12-foot travel lanes, two 5-foot bike lanes, and two 8-foot sidewalks.
A 77-foot wide bridge is about the same width as the Burnside Bridge. This cross-section can be used with all the
alignments recommended for advancement.
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F (3-lane, 80 feet wide)
A single-level bridge replacement with three 12-foot travel lanes, two 6.5-foot bicycle lanes, one 20-foot shared bicycle
and pedestrian path, and one 8-foot sidewalk (total width of 80 feet). An 80-foot wide bridge is about the same width as
the Burnside Bridge. This cross-section can be used with all the alignments.
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K (4-lane, 2-level, 57 feet wide)
A double-level bridge replacement with four 12-foot travel lanes and 3-foot shoulders on the upper level and a 20-foot
shared bicycle and pedestrian path on the lower level (total width of 57 feet). A 57-foot bridge width is about the
same width as the Broadway Bridge. This cross-section can be used with all the alignments.
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Combination options (Rehabilitation and Replacement) |
M (existing bridge for bike/ped only with new 2-lane vehicle bride)
This cross-section combines rehabilitation of the existing bridge for bicycle and pedestrian use with construction of
a new bridge for autos, trucks, and transit vehicles. The new bridge has two 15-foot travel lanes and two 3-foot
shoulders (total width of 39 feet). The replacement portion of this cross-section can be used with all the replacement
alignments except Yellow.
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N (existing bridge for bike/ped only with new 4-lane vehicle bridge)
This cross-section combines rehabilitation of the existing bridge for bicycle and pedestrian use with construction of
a new bridge for autos, trucks, and transit vehicles. The new bridge has four 12-foot travel lanes and two 3-foot
shoulders (total width of 57 feet). The replacement portion of this cross-section can be used with all the replacement
alignments except Yellow.
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Read about the eliminated cross-sections by clicking on the words below.
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B (3-lane, 63 feet wide)
A single-level bridge replacement with three 12-foot travel lanes, 16-foot shared bicycle and pedestrian path,
and 8-foot sidewalk (total width of 63 feet). The preferred 3-lane cross-section (Concept F) was included.
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G (4-lane, 92 feet wide)
A single-level bridge replacement with four 12-foot travel lanes, two 6.5-foot bicycle lanes, one 20-foot shared
bicycle and pedestrian path, and one 12-foot sidewalk (total width of 92 feet). Concept E (77 feet) includes
similar functions in a narrower width and so this cross-section was eliminated from further study.
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H (2 auto/truck lanes, 2 transit-only lanes, 92 feet wide)
A single-level bridge replacement with two 12-foot travel lanes, two 12-foot transit/shoulder lanes, two
6.5-foot bicycle lanes, one 20-foot shared bicycle and pedestrian path, and one 8-foot sidewalk (total
width of 92 feet). Concept D (75 feet) includes similar functions in a narrower width, so this cross-section
was eliminated from further study.
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J (2 lane, 2 level, 39 feet wide)
A double-level bridge replacement with two 15-foot travel lanes and 3-foot travel lanes on the top
level, with a 20-foot shared bicycle and pedestrian path on the lower level (total width of 39 feet).
Concept I is similar, but is a rehabilitation rather than a replacement; so it was eliminated from
further study.
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