Feature

Distinct at its Core: The Innovative Use of BubbleDeck at Entrada

Oct 08, 2020

Kristy Eudy

Standing at almost 150 feet, the Entrada creative office is a towering structure taking shape and making its mark amid a skyline of growth across Culver City. Emerging off the 405 Freeway near Sepulveda, six elevated office floors are seen atop five levels of parking, with an additional level underground. A striking introduction is made upon entering the site at Centinela Blvd, with overhanging cantilevers jutting forward and an expansive view of the palatial ground floor, housing forthcoming shops and restaurants.

At the point of recently topping out, the grandeur of Entrada is evident as the smooth concrete finish and sprawling open surfaces are already showing off. Prior to installing the sleek curtain wall, the shell of the building currently boasts what will be the future floors and ceilings—to be sealed and used as they are, revealing the true character of the edifice.

Constructing Entrada in this manner, with extensive open spaces, and the minimal interruption of columns, is only possible because of how the core of each level was made. Unlike traditional methods of post-tension or waffle slab applications, Entrada’s decks instead contain a hollow BubbleDeck lattice that help sustain its design and make it one of the largest projects in the state--covering over 700,000 square feet of the monolithic-like building.

Originating in Denmark and used throughout Europe in the last few decades, use of the BubbleDeck is gaining speed in the US due to its environmental benefits and its reduction of concrete. The BubbleDeck grids are fabricated off site and contain cross sections of rebar and recycled hollow balls spaced out between the bars. This wire mesh cage, which measures approximately 8 ft by 20 ft, is then placed on top of a layer of rebar that is installed on a formed plywood deck and topped with an additional layer of rebar—creating a sandwich around the bubbles. The concrete is initially poured four to six inches, allowing it to set and hold the bubbles in so they do not float as the second layer is poured. During the pour phase of the project, Entrada maintained a schedule of 11,000 sf deck pours every other day.

According to the project’s structural engineer, without the use of this method, the seismic weight would be nearly 40% higher with all the concrete used. Meanwhile, the void created by the bubble cells allows for a wider column placement of up to 45 feet. For Entrada, the method is advantageous from an aesthetic standpoint. Less columns are needed to interrupt the space, and potential deflection issues are minimized.

Early in the design stage, KPRS Division Manager Corey Evans consulted with the architect and engineering teams to propose the method and employ its use within the structure. As the workplace is changing, with the desire for flexible, creative environments meant to inspire, the design and construction of Entrada were adapted to meet those needs.

The purposefully stacked offices of the mixed-use development will provide sweeping views for tech and media companies seeking sought-after space in Culver City. Multiple balconies and a sky-deck at the first office floor bring an ease of connecting outdoors. As Entrada is constructed with more versatility for the end user, KPRS anticipates its meaningful impact in the region as industry leaders soon occupy its floors.