Alton Amphitheater 

         

       

Alton Riverfront Amphitheater: Balance and Harmony

While concert-goers enjoyed the inaugural Big Gig live music festival, many of them admired the beautiful new Alton Riverfront Amphitheater where the event was held. But most of the music lovers weren’t consciously aware that weathered segmental retaining wall (SRW) units and concrete pavers had a starring role in this project.

The new Amphitheater, part of the Alton Riverfront and Marina District Master Plan recently completed for the City of Alton, Illinois is the centerpiece of the ambitious renewal of the Alton riverfront vicinity of this historic town on the Mississippi River. This stunning redevelopment project was lead by a team of construction and design companies who worked hand in hand with the City of Alton leaders and municipal representatives including Phil Roggio, Director of Development and Housing, Design and Construction. The project design team and construction oversight was lead by Dan Bockert of Planning Design Studio, who is the company’s Principal and also served as the Project Manager.

According to Bockert, the diverse options of the SRW and concrete paver product lines made a major difference in the aesthetics of the overall project vision. "The range of material color and texture choices offered helped us to coordinate finishes between all the concrete in the project." The Amphitheater portion of the project was designed by Planning Design Studio to be seen as part of the overall open space concept, and centers on a central circular fountain geyser and a concentric circle of pedestrianfriendly, smaller vertical fountains. This central fountain area consists of a series of decorative paved areas and grassy open space, and the paving was created with contrasting color and texture to depict the theme of "the meeting of the great rivers", graphically illustrating the plan view of the Mississippi River from the confluence with the Illinois River through the Missouri River Confluence to the St. Louis Riverfront.

The plaza area pavement was constructed using concrete pavers. The plaza paving is used symbolically to represent the Alton street grid in the area around the fountain, and the fountain represents the geographic location of Alton along The Mississippi River when viewed from above the plaza. The varied modular paver units radiate from the "center" fountain, which represents the City, with the rest of the plaza paving symbolizes the region.

The Amphitheater, with a total seating capacity of 4,000 for organized events, includes 600 weathered bench-type seats using retaining wall units for the amphitheater seating and the handicap-accessible ramps. Bockert notes, "The seating walls and coping blends the line and shape of the amphitheater’s formal geometry to the natural open space of the surrounding riverfront landscape."

According to Sheppard, Morgan & Schwaab, Inc. Principal Charles Sheppard, P.E., "The weathered retaining wall units were selected for the low seating walls and handicap ramp walls because of their natural look, versatility, and ease of construction considering the varying elevations of the amphitheater bowl."

The cost of the total riverfront renovation project was approximately $4.4 million. Bockert credits the flexibility of the material with keeping the material costs low while providing a beautiful finished product. CMD

Project|
Alton Riverfront Amphitheater, Alton, Illinois

Design
Planning Design Studio, St Louis, Missouri

EWR Associates, Fairview Heights, Illinois

Architect
Sheppard, Morgan and Schwaab, Inc., Alton, Illinois

General Contractor
RCS Construction, Inc., Wood River, Illinois

SRW and Paver Producer
Kirchner Block & Brick division of Midwest Products Group, Bridgeton, Missouri

SRW Licensor
VERSA-LOK

 

 

 

 

 

 

 

 

 

 

 

 

 

SRW Tiered Walls
A tiered retaining wall system is a series of two or more stacked walls, each higher wall set back from the underlying wall. When designed properly, they not only retain soil and support loads, but also deliver an attractive appearance and provide room for plantings or seating as in the Alton Riverfront Amphitheater.
   When an upper-tier wall is placed within a horizontal distance less than twice the height of the underlying wall, the upper wall will apply a surcharge load on the lower wall. The wall design engineer must carefully analyze the site soil conditions and spacing between walls to determine overall stability of the entire tiered-wall system.

Placing the upper wall back a horizontal distance of twice the height of the lower wall (D>2H) generally eliminates the load of the upperwall on the lower wall.

Source: VERSA-LOK Technical Bulliten 7