Case Study

The Coliseum

Sectors: Structural Engineering / Stadium
Applications: Restoration of defective columns

Summary: Lindapter Hollo-Bolts provided a solution for connecting new steel plates to the original defective structural columns.

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Location: Springfield, Illinois, USA
Product: Hollo-Bolt® by Lindapter®
Contractor: Halvorson Construction
Engineer: Hanson Professional Services
Architect: Bailey Edward Design

Project Background
Constructed in 1901, this 60,000 sq ft, three-story, enclosed amphitheatre is ideal for horse shows, motorcycle training and concerts. However the venue operator, Illinois State Fairgrounds, had to close the building in 2016 due to structural engineers safety concerns brought about by its deteriorating condition. Of particular concern was the severe corrosion found at the base of the structural steel columns which required immediate remedial works.

Client Requirement
The structural engineer proposed to install bracing brackets to the columns at and below the point where they projected through the concrete riser structure, remove the lacing and then install steel reinforcement plates before adding a plywood formwork and pouring concrete for additional reinforcement. A solution for the connection of the steel reinforcement plates to the existing columns was therefore required.

Design Solution
The engineer decided to specify Hollo-Bolt by Lindapter, an expansion bolt that requires access to only one side of a Hollow Structural Section (HSS). Hollo-Bolt was chosen as it offered significant benefits including, fast installation, high strength capacity, and a range of independent technical accreditations, which include the CE Mark, TÜV and ICC-ES Seismic approvals.

Installation
The contractor used size 3/4" hexagonal head Hollo-Bolts to connect the steel reinforcement plates to the original steel channels of the columns. Installation was carried out from the exposed sides of the columns where there was free access. Each bolt was tightened with a torque wrench to the recommended tightening torque to provide the necessary clamping force.

Result
The specification of Hollo-Bolts provided the necessary reinforcement to the columns. This allowed the rest of the structure to be restored and repaired with the venue officially re-opening in 2019 with a ceremonial ribbon cutting event performed by Illinois Governor J.B. Pritzker.

Hollo-Bolt Benefits

- Fast, cost saving installation from one side
- For square, rectangular and circular hollow sections
- High resistance to shear and tension
- Unique high clamping force design

Click here to download the Hollo-Bolt datasheet.

Watch our installation video below.