Engineering behind Levi's® Stadium

Every fall since 1946, fans in San Francisco have been able to watch the five-time Super Bowl Champion 49ers in action, from Kezar Stadium to Candlestick Park, and now at Levi’s® Stadium in Santa Clara. Through its engineering and design, Levi’s® Stadium has aimed to provide the best fan experience of all of the stadiums and has changed the dynamics of live sporting events. Not only does Levi’s® Stadium enshrine the legacy of the 49ers, it also reflects state-of-the-art engineering and promotes environmental sustainability. Known for being the most technologically-advanced stadium in the world, Levi’s® Stadium has been at the forefront of innovation ever since it opened in the summer of 2014.

Levi’s® Stadium is designed as an open-air structure. The Latin root words for structure are stru and struct, which means “to build.” An open-air structure is a shelter or multi-story building which is not enclosed, is designed for event use (like for 49ers games), and has the ability to support a lot of people. Structures are systems such as a building or a tower which are built from various parts that support vertical or horizontal loads, or weight. Structural loads are forces applied to a structure or its parts. Loads can, at times, cause stress on structures. Overloading a structure can cause harm to the components of the structure or make it fail, so loads are always considered when designing a structure. Levi’s® Stadium supports much of the weight (load) of the overlying parts of the building that are created by weight and stress on the sides (horizontal), as well as on the top and bottom (vertical) of the structure.

When Levi’s® Stadium was designed, various competing loads needed to be taken into account. The stadium provides higher and lower levels of seating for close to 70,000 fans. On the west side of the stadium, an eight-level tower supports a press box, 170 luxury suites and 9,000 club seats. There are also two massive high-definition video boards located behind the stands at each end zone.

If you take a moment to observe the world around you, you will see examples of both small and large structures. Small structures might include things like stadium seats, desks or windows. Large structures, like Levi’s® Stadium, can contain multi-story buildings, bridges, monuments, and even dams. To build such structures, experts who are trained in the field of engineering are hired to focus on the design and implementation of load-bearing formations. These experts are called structural engineers.

Structural engineering is an engineering specialty or career field that focuses on the creative design, planning, construction and maintenance of permanent and temporary structures. There is also a strong focus on the support of structural systems. Structural engineering involves the application of many subjects, especially science and geometry. Structural engineers study geometry -- an area of math that deals with measuring and understanding relationships between points, lines, angles and shapes -- to help them better understand how form applies to structural support. Throughout history, engineers have used geometric shapes to build famous structures, from the Greek Parthenon in Greece to the Empire State Building in New York City. If you look around your neighborhood, you will see how geometric shapes are used in almost every structure. In the design of Levi’s® Stadium, you will see triangles, squares, rectangles, arches and other geometric forms that reinforce this remarkable structure.

Structural engineers also study physics, an area of science that studies the way matter interacts through motion in space. Physics helps them better understand how stadiums can stand tall and stable against the forces of wind and gravity, and helps them understand how forces affect different types of building materials.

Structural engineers ensure that large buildings, like Levi’s® Stadium, are strong enough to withstand environmental forces and loads. Because the stadium is located in the Bay Area, where earthquakes are a common occurrence, Levi’s® Stadium engineers had to complete thorough research and testing of its design and material, and design the stadium so that it does not collapse or behave in undesirable ways while hosting the 70,000 49ers fans who attend on a weekly basis during the football season.

Through vast research and the testing of stadium’s beam materials, practical design solutions were developed to promote safer, more environmentally friendly structures like Levi’s® Stadium. The stadium’s structural engineers worked in teams to perform strength calculations on all of the materials used to construct the stadium, and they supervised the drafting and implementation of its designs. Stadium engineers had to critically test beam and anchor strength to support over 80,000 cubic yards of concrete. A cubic yard is the volume of a box that is 1 yard long, 1 yard wide and 1 yard high. Beams are horizontal wood or steel pieces spanning a distance between one or more supports, that support weight across the its length. Anchors or anchorage points are the connections for both vertical and horizontal beam systems that support a designated weight. A cubic yard of concrete approximately weighs 4,000 lbs., and one ton equals 2,000 pounds. So, the total weight of concrete these beams need to support is 160,000 tons! That equates to about 21,000 full grown elephants--now that is a lot of weight!

Stadium engineers also utilized trusses in in the design of Levi’s® Stadium to support such loads. The basis of the truss is the use of triangles, the strongest and most rigid geometric shape, in the design of a structure to support the loads (weight) and forces acting on a structure. Trusses are used in a variety of ways in architecture, and are extensively implemented in the design of bridges, buildings (particularly in stadiums), and in tower construction projects that need to support a lot of weight, but also minimize the weight of the structure itself. Trusses utilize the strength of the triangular form in its design because each angle is fixed and held firmly in place by the side opposite it and when a force is applied to the truss, the resulting force is directed sideways rather than down reducing any bending movement that may occur on the beams of a structure. This construction feature allows Levi’s® Stadium to be as stable as can be and effectively support competing loads.

Other structural engineers working on the project specialized in the research and actual construction of the stadium. They often work with a variety of other professionals such as architects, exterior/interior designers and mechanical and electrical engineers to ensure that a multitude of features were incorporated into the overall design of club and fan spaces.

The structures you see in Levi’s® Stadium all came to fruition through the creative application of structural design. Levi’s® Stadium was designed, constructed, and tested by professionals systematically applying their knowledge of the engineering design process. The engineering design process brings together various studies and technologies to help solve real world problems or to meet human needs. Often, engineers have to invent products or systems that either never existed before or that improve existing products or systems. Solving problems often takes a multi-step continual process, and most problems have more than one correct solution. As the solution to a problem develops, engineers and designers continually refine their designs to provide the best solution.

Inside the stadium, the primary structural design goal was to bring fans as close to the game as possible. Structural engineers took into account line of sight and sound amplification to magnify cheers from fans during games. The shape on the upper fan deck at Levi’s® Stadium plays a key role in how sound is amplified during 49ers games. The upper and lower decks are essentially large parabolas, or curves, that direct the sounds of the fans to the playing field, thus creating higher noise levels during the game. The element of design that creates such increased noise is the overhanging fan decks that reflect sounds back into the stadium. Fans’ cheers reflect off the bottom of the upper deck, and back onto the field. Also, the suite tower on the west side of the stadium has just 35 rows of lower-level seats in front of it. With most of the fans located on the east side, the sound from behind the visiting sideline is expected to hit the suite tower and reflect back to the playing field. This did not happen by accident, but was meticulously planned by structural engineers. 49ers fans now hear a dramatic increase in sound level. And if you’ve ever attended a 49ers game, you know the fans are more energized by the amplified sound, making them cheer even louder.

One of the engineering initiatives driving the design concept for Levi’s® Stadium was sustainability. Levi's® Stadium is the first NFL stadium to open with LEED (Leadership in Energy and Environmental Design) Gold Certification by the U.S. Green Building Council. LEED certification is the recognized standard for measuring building sustainability and measures its certification of how the five “green” structural categories (sustainable sites, energy and atmosphere, water efficiency, materials and resources, and indoor environmental quality) are met and implemented. The stadium meets LEED’s standards in structural design by generating clean energy. Its design reduces the environmental impact through the use of reclaimed or salvaged materials. The stadium has a sustainable green roof and recycles water to promote water conservation.

The main goal of Levi’s® Stadium’s structural engineers was to ensure that this new high-profile structure was safe, durable and sustainable, and they used scientific and technological innovation to meet those goals. Structural engineering directly impacts the safety and durability of the buildings and structures we live, work and play in. Structural engineering tells us which resources and materials are useful for structures and how they can be used efficiently. In Levi’s® Stadium, structural engineering helped us accurately estimate safe weight requirements for our stadium stands and it also helped us know the maximum magnitude of force that our east tower could endure during an earthquake. By combining safety, functionality and even aesthetics, structural engineering satisfies all needs, including the needs and demand for 49ers fans to go cheer for their favorite football team.