Initial Condition Assessment: Concrete Traffic John Lawler & Joshua Freedland WJE PowerPoint Presentation Template

Intro to WJE Interdisciplinary engineering, architecture, and materials science firm; Founded in 1956 Specialized in the evaluation and repair of existing structures

Background: Construction of Concrete Traffic 1967 Cadillac DeVille Cage of rebar and welded wire fabric (mesh) Plywood forms supported with steel angles Ready-mix concrete Cast in January 8, 1970 Concrete likely needed accelerator - Typical in Chicago at that time: calcium chloride 0-60: 5.7 sec. WJE PowerPoint Presentation Template

Background: Distress Mechanisms in Concrete Structures Corrosion Carbonation Chlorides Cyclic Freezing and Thawing/Scaling Structural Loading Volumetric Changes Drying Shrinkage Thermal Contraction

Initial Assessment of Concrete Traffic Visual Survey GPR (Ground Penetrating Radar) Concrete Sample Electrical Continuity BETTER PHOTO FROM NATE? WJE PowerPoint Presentation Template

Findings: Visual Survey Overall concrete condition Honeycomb Previous repairs (Two types) – at least one is original WJE PowerPoint Presentation Template

Findings: Visual Survey Cracking – at bottom and at corners Front Left Rear Right

Findings: Visual Survey Cracking – at corners Front Right

Findings: Visual Survey Cracking - Vertical & Structural and Shrinkage Front Right

Findings: Visual Survey Cracking - Vertical & Structural and Shrinkage

Findings: Visual Survey Cracking - In repairs

Findings: Visual Survey Corrosion of Angles

Findings: Visual Survey Corrosion of Angles

Findings: Visual Survey Concrete Distressed Caused by Corrosion of Angles

Findings: Visual Survey Freeze-thaw/Scaling distress

Findings: Visual Survey Organic Growth

Findings: Visual Survey Iron Staining Misc. sealant

Findings: Visual Survey Underside condition Support of “X-frame”

Findings: GPR Cracks do not line up with reinforcing cracks not corrosion WJE PowerPoint Presentation Template

Findings: GPR Right Side Left Side Middle of face WJE PowerPoint Presentation Template

Findings: GPR Deflection in roofline 5 in. Front of roof Middle of roof WJE PowerPoint Presentation Template

Findings: GPR Surface Concrete thickness Cover over steel Top (hood, roof, trunk) 6 to 8 in. 3-1/2 to 6 in. Sides (right and left) 4 to 8 in. 1-1/4 to 5 in. Back 6-1/2 in. 3-1/4 to 4-1/2 in. Front 7 to 8 in. 0 to 4 in.

Reinforcing Cover Depth (in.) Findings: GPR Element Reinforcing Cover Depth (in.) Depth of Car (in.) Min Max Average Top of Sculpture - Hood 4.0 6.3 5.5 6.2 8.6 Top of Sculpture - Top 3.5 5.6 4.8 5.9 6.6 Top of Sculpture - Trunk 4.3 5.7 7.1 Right Side of Sculpture 1.3 3.2 2.1 4.2 Left Side of Sculpture 1.7 4.9 2.7 5.4 8.0 Back of Sculpture 3.3 4.6 4.1 6.8 Front of Sculpture 1.2 2.3 6.9

Findings: Concrete Sample Sample from over angle from front of car Freeze-thaw damage – concrete not air entrained Chloride content = 0.043% chloride by mass of sample– acid soluble Threshold is approx. 0.03 ppm Carbonation = ~1/8 in. Cause of corrosion likely admixed chloride

Significance of Observed Distress for Durability of Concrete Traffic Corrosion of angles Cracking at corners Corrosion of embedded steel (?) Freeze-thaw/scaling Vertical cracking at rear support Cracking - in original repairs & vertical cracks Organic growth (algae) Isolated other stains

Repair Options: Corrosion of Angles Cathodic Protection Impressed Current (Active) Galvanic (Passive) Chloride Extraction Remove Angle (?!) WJE PowerPoint Presentation Template

Repair Options: Other Items Overall concrete distress Water-repellant sealer (silane) – keep dry Cracking Crack Injection Crack Filling Organic Growth Cleaners IMAGE FOR CLEANING? IMAGE FOR CRACK INJECTION? WJE PowerPoint Presentation Template

Next Steps for Investigation Condition Survey Crack widths Petrographic Analysis Chloride Testing Half-cell potential survey Steel Section Loss Repair Development Cleaning studies JDF-do we want to try injection for cracks? Also some isolated iron staining Isolated sealant goo? WJE PowerPoint Presentation Template

Thank you

New Site on CAMPUS The site must be prepared with a custom made structural support frame and waterproofed pad, designed in collaboration with structural engineers and under the conservators recommendations. The site must also fulfill the following criteria: It should also not be under or too close to a tree with falling leaves. It should be in an area with reasonably dense pedestrian traffic and good lighting to protect it from vandalism. It should be where a real car could be, but it should be protected from collision with moving cars and regular street maintenance such as salting, street cleaning and snow ploughing. When it returns to campus we don’t want it to be moved again, it needs to be on a specially made waterproof pad so the site must be considered permaent. There should also be a hidden Structural support frame will be made for the car itself rather than the to support the concrete. The considerations for the site have also been specified by Christian Schieidemann, not to allow for further increased biological growth, to be visable and well monitored, and to be in keeping with its original position at the MCA where a car should be yet protected from road hazzards .

Landscape design for north resident hall and commons by studio gang The University is undergoing a period of construction so finding a site must be included in a current planning phase. The committee for campus art has just recommended the sculpture's inclusion in the landscape for the new North Resident Hall designed by Studio Gang. It would be in the area where a road ‘used to be’ – Greenwood Ave’ close to the Smart Museum and Art History Department, making a statement of the commitment to the Arts in this part of the campus and highlighting the significance of the sculpture in the University collection/ Landscape design for north resident hall and commons by studio gang Due for completion in 2016