Space Power Facility Dome Waterproofing

Title: Space Power Facility Dome Waterproofing

Award Category: Waterproofing

Project Address/Location

NASA Glen Research Center
Plum Brook Station
Sandusky, OH 21202
United States

Submitted By: Steven Bentz

Company Info

Building Envelope Consultants and Scientists

1103 North Washington St. Third Floor
Third Floor
Baltimore, MD 21213
United States

7034027121

[email protected]

Project Description and Background: The Space Power Facility is the world’s largest vacuum chamber located at the NASA Glenn Research Center’s Plum Brook Station in Sandusky, OH. The 100-foot diameter, 122-foot tall dome structure houses equipment that can simulate the vacuum of space. The Space Power Facility was constructed in 1969 and has tested the International Space Station’s radiator and solar arrays, the Mars rover landing systems, and most of the nation’s major rockets. The Contractor was retained to perform waterproof coating application on the domed structure along with the necessary concrete repairs to provide a sound substrate for waterproofing application. The Contractor recognized immediately that there was a need for specialized access and safety systems on this project. The Contractor determined that they would perform the work using a combination of pipe frame scaffold stairs, swing stage scaffold, and Industrial Rope Access (IRA) methods. BECS (the Consultant) was retained by the Contractor to assist in the development of safe access systems as well as providing consulting services related to the waterproofing systems and concrete repairs. During the course of the work, life safety and equipment anchors were designed, located on the dome, tested, and certified by the Consultant, along with utilization of the existing lightning protection stanchion (finial) at the top of the dome as a fall restraint anchor, which was analyzed and certified by the Consultant.

Scope: During the course of the work, life safety and equipment anchors were designed, located on the dome, tested, and certified by the Consultant, along with utilization of the existing lightning protection stanchion (finial) at the top of the dome as a fall restraint anchor, which was analyzed and certified by the Consultant. Original structural drawings from 1963 show the finial as a 12-inch diameter, SCH 40 steel pipe anchored to the approximately 5’-6” thick concrete dome with embedded reinforcing steel and a ½-inch thick base plate set in a grout pocket. The drawings also indicated a dense reinforcing pattern with limited areas for anchor installation. The Consultant provided Ground Penetrating Radar (GPR) scanning services to assist in determining the location of the anchors. The Contractor developed a rigging plan and determined placement of the anchors for the most efficient use and movement of the swing stages. The Contractor requested that the anchorages be designed and rated for a higher 10,000-pound load in order to allow for safe use in multiple directions and to account for conditions such as high winds, variable angles of use, and the potential for the anchorages to be left in-place long term. The Contractor was introduced to the specialized IRA methods for access to this dome by the Consultant. The Consultant and Contractor collaborated on a joint certified user training for their respective personnel to understand these access methods. The development of the safe access on this project was critical to the waterproofing application. Being mindful of how the rigging would move across and around the dome was important to achieving a quality installation and finished product. the Contractor needed the anchorages to be usable for multiple applications and orientations and load directions. BECS designed the system to take twice the typical OSHA rated load for use in these varied applications. Waterproofing products used were provided by Sika along with concrete repair products for partial depth topside repairs.

Solution: Uniqueness: domed structure, ~5.5' thick concrete. Only one point of tie-off at the peak. State-of-the-art materials: The materials used were Sika waterproofing systems, Sika concrete repair materials, Hilti expansion anchors, and stainless steel welded plate. While these materials are not "state of the art" in the purest definition, their application to this domed structure was an advanced application of readily available materials to a complex problem. Sustainability/Aesthetics: The coating used was white and highly reflective, this provided a gleaming "new" roof and also should reduce the cooling costs in the summer. When you consider that the interior of the dome is meant to replicate the vacuum of space, a reduction in cooling costs could be quite significant here. Value Engineering: The Consultant worked with the Contractor to come up with a "happy middle ground" for the design of the anchorages and their placement. Initially the plan included 30+ anchors, by the time the value engineering process was completed only 18 anchors were installed. Functionality has been discussed in other portions of this submission.

Value: This project was made possible by consultant-contractor collaboration in the design and implementation of safety systems for facade/roof access. The domed structure presented a nearly inaccessible situation that needed to be accommodated with three different access systems, pipe frame scaffold, roof/ground rigged swinging scaffold, and industrial rope access. Waterproofing application on a domed structure such as this requires attention to the detail of mil thickness, bucket count, and coverage rates while still maintaining safe access and ensuring that rigging lines do not damage completed work. In typical "best practice" the expectation is that no traffic will occur over completed work, but due to the radiused nature of this dome and the relatively small "flat" area atop the structure for safe work, it was impossible to not traffic over something that was previously completed. By implementing proper safety measures for multiple staging methods the contractor was able to complete this project and deliver a quality project. The Consultant provided the value of designing the safety systems that allowed the waterproofing project to be completed. Teh existing reinforcing cage of the dome was incredibly dense (tightly spaced). The Consultant was called upon to provide Ground Penetrating Radar (GPR) scanning services in order to assist the contractor in locating sufficient voids in the reinforcing pattern where they could install the safety anchors. The value added to the project here was the ability to adjust the use plan as needed to allow for anchor installation at alternative locations.

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