PFEIFER packs a punch in SoFi Stadium

Article posted by Coliseum, December 29^th, 2020

Image: Pfeifer

From a small family ropery to an internationally operating group of companies, the PFEIFER Group has come a long way. The PFEIFER Group – with its headquarters in Memmingen (Germany) – boasts more than 1,000 projects worldwide.

Today, it has graduated from the hemp rope through to constantly new application-based options in light-weight structures.

SoFi Stadium sets a benchmark

PFEIFER has completed the ETFE roof canopy structure atop the jaw-dropping newly-opened SoFi Stadium in Los Angeles, California (US).

Apply for membership

The scintillating stadium, home of the Los Angeles Rams and Los Angeles Chargers of the National Football League (NFL), as well as the host site of the 2028 Summer Olympics, is a landmark as far as stadium construction is concerned. Designed by HKS Architects, structural engineering firm Walter P Moore, and the Turner Construction/AECOM Hunt Joint Venture, SoFi Stadium is the first ‘indoor-outdoor stadium’ to cash in on the famous Southern California weather of an outdoor stadium, while utilizing a roof structure to cover the interior from any weather vagaries.

Image: Pfeifer

The (approximately 1 million square foot) roof comprises 302 ETFE panels, including 46 operable vents that can open, allowing the heat which will be generated by the more than 70,000 spectators inside the facility to rise up and get ejected out of the eye-catching venue. The ETFE roof and secondary steel are supported by a 1,450 ton, 75,000-foot-long double grid cable net system. The cable system supports the roof, shaping the roof’s convex profile.

The design phase

Starting from first contact, discussion on feasibility, design assist/consulting, defining scope – PFEIFER was totally involved in the design phase.

The production phase

Starting from production, timeline, total yield (how many tons of steel, cables, ETFE, etc.), how the company adjusted to compensate for a project this large, how the global outbreak of COVID-19 affected production and how the internationally operative group of companies overcame that hurdle, to the last truck going out, PFEIFER managed everything smoothly.

The installation phase

Starting from first arriving to site, receiving materials, the timeline of the installation process, overcoming challenges, how COVID almost derailed the entire installation process and how the stumbling blocks were overcome, to giving the final touches, both PFEIFER America and Europe carried out the tasks in the most efficient manner and also learned a lot of lessons in the entire process which was full of challenges. The different entities involved in the whole development also extended full cooperation in the splendid SoFi Stadium construction process.

Trendsetter

SoFi Stadium, the breathtaking new home to two NFL franchises, set out from the beginning to become the standard by which all stadia will be compared. With a development and construction cost reportedly in excess of five billion dollars, this is the most ambitious stadium ever built. SoFi Stadium is the centerpiece of a 298-acre mixed-use development featuring retail, commercial office space, a hotel, residential units, and outdoor park spaces.

Image: Pfeifer

PFEIFER Structures was contracted in a design-assist role with the project consultants in developing a technically and commercially viable cable net roof structure and ETFE cladding system, as well as overall project budget, schedule and coordinated logistics plan.

Informed Jassen Mihaylov, Head, BU Tension Members, PFEIFER Structures, “The stadium has been built with an arching steel truss compression ring supporting a double grid cable net roof covered with translucent ETFE and surrounded with perforated aluminum panels. The roof, the largest of its kind ever built, consists of 302 ETFE panels including 46 mechanized vents that allow the heat generated by spectators inside the arena to dissipate.”

Mihaylov added, “The massive roof consists of more than 1,400-tons of double orthogonal grid steel, and approximately 67,000 tons of ETFE membrane, secondary steel, gutters, cross clamps, cable struts, and retractable vents. The 20,000-ton steel truss compression ring reaches the ground at three points and has additional support from 37 earthquake-resistant columns as high as 100-feet from grade. The 13-acre stadium roof is open on three sides and is a completely separate structure seismically isolated from the stadium bowl.”

Another unique feature of the stadium, situated on the flight path of the nearby Los Angeles International Airport, is an enormous installation of 28,000 V-Pix LED lights on the roof that will create a 13-acre high resolution video display when viewed from above.

Image: Pfeifer

Constructing the largest cable net roof ever built for a stadium, one that free spans over 1,000 feet longitudinally and 800 feet tangentially required one of the heaviest cable structures and subsequently one of the highest cable pinning forces ever attempted at approximately 2,000 kips. In fact, the stadium’s steel and concrete bowl structure could not support the static dead load from the cable grid let alone the dynamic movement imposed during the cable jacking and erection process. To overcome this challenge, the upper and lower cable nets were divided into a total of 18 individual nets and significant scaffolding, matting, bridging, and shoring was involved to reduce the imposed cable loads on the stadium bowl structure to acceptable levels.

PFEIFER began mobilizing at the stadium site in December 2018. The main cable net was completed in September 2019, the ETFE secondary steel and cladding was completed in June 2020, and the commissioning of the retractable vents and roof-mounted LED was completed in September 2020.

PFEIFER – the go-to company

PFEIFER helps realize visions and takes up with total élan the challenge of taking part in a prestigious project as has been proved in the case of SoFi Stadium.

The company knows how to meet looming deadlines and is perfect in the art of developing an installation method that is as flexible and controlled as possible. It is due to PFEIFER’s efforts that SoFi Stadium today boasts being the biggest single-skin ETFE stadium in the world.

Advantage PFEIFER

PFEIFER simplifies installation on job site – usage of preassembled construction elements;
Prevent existing structure from damage – find solutions to avoid damages on the existing parts of the construction;
Helps establish a reliable logistics network – flexible ways of transportation always focused on the deadline;
Prepares work space prior to installation and helps to simplify the entire installation process; and
PFEIFER also ensures that it hires the best installation team.

Image: Pfeifer