Sheehan Partners with URS Corporation [Chicago Design Studio]
Architect: Sheehan Partners, Chicago—Neil Sheehan, Sylvia Billisics, Camilla Bryant, Debbie Erickson, Keren Fiorenza, Ceri Holroyd, Catherine Murray Engineer: URS Corporation, Chicago—Mohammad Hassan, Steve Stroh, Donald Yetter
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35th STREET | 41st & 43rd STREET | CHICAGO RIVER | NORTH AVENUE |
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Architect's Statement
All of Chicago's neighborhoods share the lakefront. The water, beaches, parks and Lake Shore Drive knit the city together from north to south. The construction of a series of pedestrian bridges connecting the neighborhoods to the lakefront across Lake Shore Drive offers the opportunity to reinforce the shared experience of the City.
The bridge design presented here, to be located at 35th Street, rises over Lake Shore Drive and the Illinois Central/Metra Electric Lines with a gentle slope that is accessible as a direct extension of the existing pathways that parallel the lake along Burnham Park with direct connections to the neighborhood streets and walkways. This sloping north-south path allows easy circulation for cyclists, rollerbladers and pedestrians with minimal intrusion on the lakefront park.
The spans over Lake Shore Drive and the rail tracks follow two opposing parabolic arcs with east-west spans of two hundred and thirty feet and cantilevered projections of one hundred feet. The structure is anchored in oval formed bases that provide the resistance required to restrain post-tensioning cables that run through the bridge decks. These base elements provide stairway access to the bridge and the space within the base on the park side can be occupied by public amenities such as bicycle or rollerblade rental or café.
The oval base form extends above the bridge deck with an asymmetrical cone shaped framework of steel covered in perforated steel panels. These thirty-five foot high lanterns function as monuments for drivers along Lake Shore Drive creating a common theme for the drive along its length. These lanterns also serve as markers for the location of the bridges for cyclists and pedestrians as they make their way along the lakefront. With their asymmetrical shape the form of these lanterns changes with the angle of view.
During the day these lanterns have a translucent quality, substantial and insubstantial at the same time. At night they are lit from within to become great lanterns. This lighting will vary in color and pattern to create a distinct identity for each. Located on either side of the roadway, these lanterns will become gateways for drivers as they make their way along Lake Shore Drive.
This use of lighting as an integral element of design is continued across the bridge spans where a parabolic curved cover of perforated stainless panels screens the concrete structure behind. The translucent and reflective character of these panels serves to lighten the apparent mass of the structure and create a sense the eight-inch thick bridge deck is floating above the roadway and rails. This effect is reinforced at night as lighting washes the curved face of the concrete structure shining through the perforated metal panels. The bridge will appear to float on a band of light.
The structure above the bridge deck is minimized with simple guardrails of stainless metal mesh. This allows the bridge to be experienced not as an enclosure but as an extension of the lakefront pathway system open to the surroundings and the views offered as the elevation of the bridge deck rises. The apex of the bridge, floating over Lake Shore Drive, with views to the skyline and the lake will become a stopping place along the path of the bridge.
Constructed of cast-in-place concrete, the bridge spans are supported on oval concrete abutment caps with counterbalance weight buried in the approach walkway beyond the abutment. These abutments will provide anchorage for post-tensioning cables. The spans will consist of cast-in-place trapezoidal box girder superstructure with integral deck. During construction the concrete structure will be cast in formwork supported by overhead false work. This will allow Lake Shore Drive and the rail lines to remain open and unobstructed during construction. After casting and curing of the concrete box girders between the abutments, post-tensioning cables will be installed through the box girders. The tensioning of these cables will create positive moments across the mid span and negative moments at the abutment supports to complete the structure. With tensioning complete the false work can be removed and finish components installed.
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Architect's Statement
All of Chicago’s neighborhoods share the lakefront. The water, beaches, parks and Lake Shore Drive knit the city together from north to south. The construction of a series of pedestrian bridges connecting the neighborhoods to the lakefront across Lake Shore Drive offers the opportunity to reinforce the shared experience of the City.
The bridge design presented here, to be located between 41st and 43rd Streets, rises over Lake Shore Drive and the Illinois Central/Metra Electric Lines with a gentle slope that is accessible as a direct extension of the existing pathways that parallel the lake along Burnham Park with direct connections to the neighborhood streets and walkways. This sloping north-south path allows easy circulation for cyclists, rollerbladers and pedestrians with minimal intrusion on the lakefront park.
The spans over Lake Shore Drive and the rail tracks follows two opposing parabolic arcs with east-west spans of two hundred and thirty feet and cantilevered projections of one hundred feet. The structure is anchored in oval formed bases that provide the resistance required to restrain post-tensioning cables that run through the bridge decks. These base elements provide stairway access to the bridge and the space within the base on the park side can be occupied by public amenities such as bicycle or rollerblade rental or café.
The oval base form extends above the bridge deck with an asymmetrical cone shaped framework of steel covered in perforated steel panels. These thirty-five foot high lanterns function as monuments for drivers along Lake Shore Drive creating a common theme for the drive along its length. These lanterns also serve as markers for the location of the bridges for cyclists and pedestrians as they make their way along the lakefront. With their asymmetrical shape the form of these lanterns changes with the angle of view.
During the day these lanterns have a translucent quality, substantial and insubstantial at the same time. At night they are lit from within to become great lanterns. This lighting will vary in color and pattern to create a distinct identity for each. Located on either side of the roadway, these lanterns will become gateways for drivers as they make their way along Lake Shore Drive.
This use of lighting as an integral element of design is continued across the bridge spans where a parabolic curved cover of perforated stainless panels screens the concrete structure behind. The translucent and reflective character of these panels serves to lighten the apparent mass of the structure and create a sense the eight inch thick bridge deck is floating above the roadway and rails. This effect is reinforced at night as lighting washes the curved face of the concrete structure shining through the perforated metal panels. The bridge will appear to float on a band of light.
The structure above the bridge deck is minimized with simple guardrails of stainless metal mesh. This allows the bridge to be experienced not as an enclosure but as an extension of the lakefront pathway system open to the surroundings and the views offered as the elevation of the bridge deck rises. The apex of the bridge, floating over lake shore drive, with views to the skyline and the lake will become a stopping place along the path of the bridge.
Constructed of cast-in-place concrete, the bridge spans are supported on oval concrete abutment caps with counterbalance weight buried in the approach walkway beyond the abutment. These abutments will provide anchorage for post-tensioning cables. The spans will consist of cast-in-place trapezoidal box girder superstructure with integral deck. During construction the concrete structure will be cast in formwork supported by overhead false work. This will allow Lake Shore Drive and the rail lines to remain open and unobstructed during construction. After casting and curing of the concrete box girders between the abutments, post-tensioning cables will be installed through the box girders. The tensioning of these cables will create positive moments across the mid span and negative moments at the abutment supports to complete the structure. With tensioning complete the false work can be removed and finish components installed.
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Architect's Statement
For all of Chicago's neighborhoods the lakefront is a common feature. The water, beaches, parks and Lake Shore Drive knit the city together from north to south. A series of pedestrian bridges connecting the neighborhoods to the lakefront across Lake Shore Drive offers the opportunity to reinforce the common experience of the lakefront and to tie the city together.
All of the paths along the lakefront and from the city center to the west meet up at the mouth of the Chicago River. The current walks and pathways between Navy Pier and Burnham Harbor are inadequate to support the quantity and mix of traffic through this area and don't encourage connections from north to south over the river. While some provision has been made to connect the riverfront walkways through the loop to the lakefront, these paths are currently little used. As development of new housing and offices is completed along the river to the west of Lake Shore Drive these connections will become more important.
This design for the moveable bridge at the mouth of the Chicago River is intended to knit together the many disconnected paths that cross at this point and encourage connections between the north and south lakefront and between the Loop and lakefront.
Rather than providing a single span from north to south the proposed design is a six hundred foot diameter circle touching down at four corners, connecting paths across the river, across Ogden Slip and creating a clear direct path from Navy Pier to Burnham Harbor and Grant Park.
This form recalls Daniel Burnham's round form passenger steamer docks to have been located just to the south in his Plan of Chicago, as well as more recent proposals for a basin park to be wrapped around the mouth of the river.
This bridge form provides for direct connections to the surrounding pathways, it allows twenty-two feet of clearance through the river and Ogden Slip channels for tour boats and motorized pleasure boats and it opens for unlimited clearance with a simple, economical mechanism.
The bridge opens by translation or lateral movement of the bridge deck. With this approach there are no counter-weights, cables, pivots, hydraulics or other complex engineering requirements. Each quadrant or quarter of the bridge deck is divided into two sections. A moveable section is supported by a fixed section along a diagonal line between the two. The movable section slides next to the fixed section, rolling along wheels at it base. Movement is powered by a simple electric motor.
The fixed section of the bridge is a rigid concrete tube that supports the moving deck and provides grade level landings at three corners. The bridge will be controlled from the existing bridge house at the adjacent Lake Shore Drive bridge.
Each of the four moveable bridge sections is constructed of a steel framework covered in perforated stainless steel panels with a lightweight concrete deck. Supported by the middle third of its span, the outer thirds of each section are cantilevers that counterbalance each other and provide for the one hundred twenty foot open span across the river.
During the day the translucent stainless panels over the structure mix the visible structural frame behind with reflected water and light. This will lighten the apparent mass of the structure and create a sense that the eight-inch thick bridge deck is floating above the water. At night the bridge is lit from within the steel framework, while the stainless mesh of the guardrail above is washed with light from fixtures recessed into the deck. This circle of light recalls the Navy Pier Ferris Wheel. Together they will add to the views of the lake from the surrounding buildings.
The structure above the bridge deck is minimized with simple guardrails of stainless metal mesh. This allows the bridge to be experienced not as an enclosure but as an extension of the lakefront pathways system open to the surroundings and the views offered as the elevation of the bridge deck rises and falls.
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Architect's Statement
All of Chicago's neighborhoods share the lakefront. The water, beaches, parks and Lake Shore Drive knit the city together from north to south. The construction of a series of pedestrian bridges connecting the neighborhoods to the lakefront across Lake Shore Drive offers the opportunity to reinforce the shared experience of the City.
The bridge design presented here, to be located near North Avenue, rises over Lake Shore Drive with a gentle slope that is accessible as a direct extension of the existing pathways that parallel the lake through Lincoln Park. This sloping north-south path allows easy circulation for cyclists, rollerbladers and pedestrians with minimal intrusion on the lakefront park and ballfields.
The span over Lake Shore Drive follows a parabolic arc with east-west spans of two hundred and thirty feet and a cantilevered projection of one hundred feet. The structure is anchored in oval formed bases that provide the resistance required to restrain post-tensioning cables that run through the bridge decks. These base elements provide stairway access to the bridge and the space within for public amenities such as bicycle or rollerblade rental or cafés.
The oval base form extends above the bridge deck with an asymmetrical cone shaped framework of steel covered in perforated steel panels. These thirty-five foot high lanterns function as monuments for drivers along Lake Shore Drive creating a common theme for the drive along its length. These lanterns also serve as markers for the location of the bridges for cyclists and pedestrians as they make their way along the lakefront. With their asymmetrical shape the form of these lanterns changes with the angle of view.
During the day these lanterns have a translucent quality, substantial and insubstantial at the same time. At night they are lit from within to become great lanterns. This lighting will vary in color and pattern to create a distinct identity for each. Located on either side of the roadway, these lanterns will become gateways for drivers as they make their way along Lake Shore Drive.
This use of lighting as an integral element of design is continued across the bridge spans where a parabolic curved cover of perforated stainless panels screens the concrete structure below the bridge deck. The translucent and reflective character of these panels serves to lighten the apparent mass of the structure and create a sense that the eight-inch thick bridge deck is floating above the roadway. This effect is reinforced at night as lighting washes the curved face of the concrete structure shining through the perforated metal panels. The bridge will appear to float on a band of light.
The structure above the bridge deck is minimized with simple guardrails of stainless metal mesh. This allows the bridge to be experienced not as an enclosure but as an extension of the lakefront pathway system open to the surroundings and the views offered as the elevation of the bridge deck rises. The apex of the bridge, floating over Lake Shore Drive, with views to the skyline and the lake will become a stopping place along the path of the bridge.
Constructed of cast-in-place concrete, the bridge spans are supported on oval concrete abutment caps with counterbalance weight buried in the approach walkway beyond the abutment. These abutments will provide anchorage for post-tensioning cables. The span will consist of a cast-in-place trapezoidal box girder superstructure with integral deck. During construction the concrete structure will be cast in formwork supported by overhead false work. This will allow Lake Shore Drive to remain open and unobstructed during construction. After casting and curing of the concrete box girders between the abutments, post-tensioning cables will be installed through the box girders. The tensioning of these cables will create positive moments across the mid span and negative moments at the abutment supports to complete the structure. With tensioning complete the false work can be removed and finish components installed.
