1932 Olympic Swim Stadium
Los Angeles, L.A., California
Restoration of the Concrete Facade of this Site of the 1932 Olympic Games Swimming Events held in Los Angeles.
The board-formed concrete facade of the decorative facade had deteriorated significantly and needed cleaning, patching, and new surface treatments to preserve and restore the surface to its former Deco glory.
Wikipedia Reference: http://en.wikipedia.org/wiki/1932_Summer_Olympics
Click on images below to view at larger size.
During a major adaptive re-use project to convert the '32 Olympic Swim Stadium into a community center and pool, the concrete facde was restored and coated with a special surface rendering to enhance resistance to the elements. |
Here are a few images to indicate how difficult it is to ascertain the extent of damage to a board-formed, cast-in-place concrete structure, without examining the facade in close detail. In each case the damage results from 'ironjacking', a term used in the restoration industry to describe the damage to surrounding masonry from the oxidation (rust)of ferrous reinforcing components (re-bar). This rusting process causes iron oxide to form on the surface of the steel reinforcement or anchor. This rusting process expands with a tremendous force, cracking the surrounding masonry or concrete and promoting the entry of more moisture and the eventual failure of the masonry or concrete. |
Notice that the displacement of the concrete surface is very subtle, but when the displaced area is poked and prodded with a chisel or rockhammer, the unstable area is quickly made evident. |
In this flat area, there is a faint outline of the possibly damaged area, but if this area were located 70 to 80 feet above ground, it would be almost impossible to accurately survey the damage without direct access of some kind. |
This chunk of conrete was removed by gently prying apart the crack with only hand movement. No tool or prying apparatus was necessary. Imagine an unrestored concrete facade in this condition undergoing a severe earthquake! |
Every section of the facade was surveyed by physically poking and prying at the evident location of re-bar damage to determine the actual area to be prepared and patched. |
After establishing the actual area of repair, the concrete is cut with diamond saw blades into smaller squares approximately 1 inch in size to facilitate ease of removal. The depth of the cut is usually kept to approximately 3/4" to control the amount of void to be filled by patching mortar. If the unsound substrate is deeper, then we cut as deep as necessary to provide sound material for the patching mortar to adhere to. |
We used several types of small and medium-sized pneumatic chipping hammers to remove the excess concrete from the repair area. |
Here the concrete is being removed with an Italian carving hammer originally designed for use with marble and limestone. We like these hammers because their rate of impact is much higher and finer than ordinary demolition hammers. They allow us to do very fine and controlled demolition of historic masonry substrates. |
After all concrete has been removed within the repair area, we sandblast the exposed steel reinforcing bar and then treat the prepared steel with an anti-corrosion coating to prevent further rusting and deterioration. |
In this image, note the rebar placed too close to the surface, which caused this deterioration in the first place. Note also the roughened surface of the repair area after the chunks of original concrete have been chipped out. This surface will provide a better mechanical bond for the new patching mortar. |
Here is the same area with the proprietary, polymer-modified cement mortar installed and finished to the adjacent profile. No attempt was made to match the color of the original concrete since the entire facade was coated after repairs were completed. |
There were several drinking fountains at the site, all of them damaged to some degree. Iron-jacking and the proximity to moisture were the most common suspects. |
This newly repaired drinking fountain shows the patching mortar installed and curing. After proper shaping and curing, the restored fountain was coated with the same cementitious coating used on the rest of the facade. |
Another challenge on this project was the repair of several large cast stone urns that were present at the 1932 Olympics, moved to storage, and later discovered and returned to the design plan. |
Several broken urns were repaired using the same proprietary mortar used on the concrete board-formed walls. In the case of the urn repair, however, an addtional layer of stainless steel expanded metal lath tied to stainless rods provided a stable armature on which to construct the final repairs. |
Since the repair mortar was Portland cement-based, the repairs were built up in layers to allow for shrinkage. |
Fragmented caps were re-assembled using epoxy adhesive and stainless steel rods. |
After mortar repairs had cured properly, all concrete surfaces were coated using a polymer-modified cementitious coating with sythetic-oxide colorants to help match the look of the original cleaned concrete. A cementitious coating is an extremely durable coating if properly applied and cured. We have observed a coating in San Franciso that was applied soon after the quake in 1906 and still exhibited very durable properties after 90 years. |
This image shows a coated surface on the left and a cleaned, raw concrete surface on the right. There is clearly very little difference in the apprarent visual qualities of the two surfaces, and the durablity and water repellancy of the coated surface will dramatically reduce and in some cases eliminate future instances of rebar failure from rust. |
The 1932 Olympic Swim Stadium is now a useful and much used element of the local community. It's great to see the ways in which symbols of our past can be usefully incorporated into the present. Wikipedia Reference: http://en.wikipedia.org/wiki/1932_Summer_Olympics |