Project Profile
By Ascent Staff Summer 2021
The newly opened Pikes Peak Summit House features a structural total precast system, allowing for a truly distinctive design approach for this public structure. This is the most unique precast concrete project Stresscon has participated in to-date. At 14,115 feet, this is the highest total precast structure (TPS) in the world.
Construction schedules in the Rocky Mountain region are known for extreme weather and high winds through multiple construction seasons. At this altitude, the extremes are tenfold when crews must battle intense temperature swings and lightening, project site geography, transportation issues, and limited oxygen.
It was necessary that the project meet Living Building Challenge (LBC) certification standards, as well as LEED certification. LBC requires that all materials meet criteria for an ultimate green building standard with materials that reduce impact and improve the project environment. As the first LBC project for Stresscon, this required extensive research and discussion, as well as a stringent approval process, to keep Pikes Peak environmentally safe. All construction works also met environmental standards with little impact on the natural surroundings. All the completed structures also meet or exceed the International Energy Conservation Code (IECC) guidelines, assuring the community that the public facility meets stringent energy efficiency requirements. Stresscon Corporation participated in the on-site precast construction of this local project over a two-year period.
Extensive coordination among the architectural, structural engineering, general contractor and precaster was necessary to ensure that the rigorous project requirements were met for this one-of-a-kind project. Design and planning meetings for the project started in early 2015. Ground breaking and precast erection began in mid-2018, with the first phase of foundation footers and concrete base. Stresscon’s precast erection started at the beginning of July 2019, and erection was finished in November 2019.
Stresscon’s precast scope and erection included a total of 462 premanufactured components, playing a primary role in the project design and construction. The precast pieces used included tees, beams, columns, flat slabs, a kinked beam, stairs, spandrels and insulated retaining walls to complete two precast concrete structures that replaced the previous visitor’s center and added a high-altitude laboratory on the top of the mountain.
The mixed-use hospitality, Pikes Peak Summit House space, was conceived to function as the heart of the mountain for all visitors making the journey to the top of the 14,115-foot peak. Offering views of Mt. Rosa to the southeast, the center provides bathroom facilities, amenities like the famous Pikes Peak donuts and snack bar, educational exhibits, a special railway entry for the Broadmoor/Manitou Cog Railway, an atrium and roof walkways to view the surrounding mountains. The visitor center was designed with a basement and a main level, with the foundation on top of bedrock. The team dug through six feet of permafrost and dealt with melting ice and pumping required to keep the foundation site functional. This building is two levels below grade on three sides.
The insulated retaining walls (8+8.5+3) provide an overall R-value of 60 with an insulation Wythe of 8.5 inches thick. (See photos) Double tees were used for the floors and roof, creating a diaphragm for lateral resistance to hold the extensive soil and wind loads. The roof level is sloped for drainage and reinforced for superimposed loading of 540 lbs. per square foot. This is made up of a dead load of 390 and a live load of 150. The roof was also designed to hold some mountain boulders on the visitor walkways. Dowels were installed from the precast and through the roof insulation to the upper concrete layer to prevent it from sliding off the roof.
The second building on the peak is a High-Altitude Research Laboratory (HARL) that is a two-level precast concrete structure featuring basement and main levels, designed for use by the US Military for high altitude exercise, endurance training and testing. Structural precast members for this facility were also designed for extreme soil and wind loads. The dormitory building’s precast retaining walls range from 19.5 to 21.5 inches thick with 8.5 inches of isocyanurate insulation, providing an overall R-value of 75. Four times the number of normal connections were required in the building’s wall system to handle the extreme soil loads. The building’s south and west walls feature buff colored acid etch finish with a form liner design that mimics the stone on the main building.
Because of the numerous sharp hairpin turns, delivery logistics had to be extremely well planned. Coordination of delivery were limited by length, width, and weight, on trailers no longer than 40 feet, and were typically half the usual load. This created a huge variable for production and erection, as the piece size was limited to 10 feet wide, max length of 45 feet, and 30,000 pounds, with no stacking of panels on the trucks. This led to most loads being one piece per load, and restricted piece size that could be used in the project. The drivers averaged six pieces per day and had to have all trailers down before the mountain opened to visitor traffic. The limited site provided enough room for seven full and seven empty trailers. Drivers followed a daily loop, shuttling precast pieces to the job site, then driving back down the mountain with empty trailers that were reloaded for the next day’s journey. A very restrictive pool of experienced drivers was also a factor, as only seven drivers were willing to handle the logistics for Stresscon.
As imagined, the top of Pikes Peak is a very restrictive job site and remained open to tourists through the length of building construction. A 250-ton hydro crane was required for the job based on engine efficiency and performance at over 14,000 feet in altitude. Special lightning rods had to be placed in the ground and hooked to the crane to protect the crane and erection crew. For this project, a 20-mile distance was established for lightening in this area. Workers at the site had to pass a physical before being allowed to work at this altitude. This high-altitude work environment produced many harsh weather conditions, tested physical levels and fitness, and created labor inefficiencies due to so many unknown and changing variables. Typical workdays were six hours or less and based on the altitude and fitness level of the employees. In many cases, altitude sickness and shortened shifts occurred due to limited oxygen at this elevation. Extremely high winds and lightning also shut down the jobsite on many occasions. The teams averaged erection of four precast pieces per day. Multiple trade interaction, and coordination of workers and equipment were required to keep the mountain open to tourists throughout the erection process.
Precast concrete was chosen for the project to meet the schedule demands, for heavy soil loads, and weather and environmental aspects. The Stresscon team worked jointly with EnCon Field Services, EnCon Design, GWWO Inc. Architects/RTA Architects, HCDA Engineers and GE Johnson Construction Company on this impressive project.
