At the corner of West Jefferson and National Blvd. Largo is pouring the concrete at the first building in southern California featuring an exoskeleton structural system with general contractor Matt Construction. The commercial building features two levels of below grade parking and 17 levels above for a total of 355,180gsf. Read more
The Entrada Creative Office in Culver City, CA is truly a unique structure combining state-of-the-art design with cutting edge engineering. The building is 13 levels tall including the roof with six levels of commercial office space above six levels of parking, one of which is below grade. The podium level is dubbed the “Sky Deck” and features a 14,000sf landscaped amenities space with a fitness center, conference room and open space for all tenants to enjoy. The 815,000gsf building along Centinela Avenue is clad in glass and metal screens with exposed concrete interior columns and walls. Drivers along I-405 will be drawn to the open-air private balconies stepping up the commercial levels on either side of the building. The rectangular office levels are rotated with respect to the lower parking floors creating a substantial corner cantilever at the west face of the building making a strong architectural statement. The load of the cantilever deck is carried by a massive structural post-tensioned upturn beam located on the West edge of the roof.
Beneath the surface the Entrada development began with three mat foundation pours averaging 4,500CY. Two of the mass concrete pours at the elevator cores required a thermal control plan to ensure temperatures did not exceed 165 degrees during placement. Parking levels hold 1,044 stalls and 695CY of shotcrete walls line the perimeter of the basement.
Elevated decks are concrete voided slabs or “bubble decks” supported by high-strength cast-in-place columns and walls. Voids are created using hollow spheres made of recycled plastic and arranged in 8’x10’ wire mesh grid prefabricated offsite. Once on site the grids are placed on a layer of two-way rebar installed on the plywood deck with another layer of reinforcing on top. Deck pours begin by placing the first 4” to 6” of readymix to secure the voids in place before the balance of the slab is poured. Elevated decks ranged between 16” to 20” with typical levels at 18” thick.
The flat plate, bubble deck system allowed architects to maximize floor space in the building with a typical bay measuring 30’x45’. Flat decks also enhanced production flow by eliminating beams, drop caps, depressions and hanging form build up. On average Largo poured 11,000sf of deck every other day during the elevated slab duration of the project.
Overall, the voided slab construction reduced the weight of the structure nearly 30% in comparison to conventional methods of waffle slab or post-tensioned decks. This measure not only limited the seismic forces and foundation loads but also reduced the environmental impact of the project with significantly less material to transport and a faster schedule. The company supplying the voids was BubbleDeck North America.
The corner cantilever at the Sky Deck level required shoring from street level to remain in place until the 3’ wide by 10’ tall upturn beam on the roof deck was poured and stressed. All six stories of office space and the roof are suspended at this corner from this same upturn beam on the roof. The corner columns of the cantilever have continuous reinforcing from the first commercial level to the roof. This feature required the shoring removal process to be reversed with the upper levels being stripped first while checking for deflection throughout the process.
Largo poured over 47,000CY in the structure over 11 months. General contractor KRPS, Gensler architects and Saiful Bouquet structural engineers aim to have the project complete in the first quarter of 2021 making it the first, large scale structural bubble deck system on the West Coast.
Largo Concrete worked with Abbott Construction on the UCLA Warner Graduate Art Studio Project in Culver City, CA.
The overall project consisted of a 21,200sf renovation of the Graduate Art Studios existing building and a 26,800sf, L-shaped addition to the facility. Design by architecture firm Johnston Marklee, the building is organized in the fashion of a ‘community’ with small blocks of private studios in a cul-de-sac setting adjacent to communal, plaza like facilities connected by pathways akin to city streets. Specialized lab space for woodworking and ceramics are also included in the facility which is designed to be adaptable to accommodate future new technologies and working methods. The Margo Leavin Art Studio project anticipates a LEED Gold Certification.
The construction of this building utilized several different concrete assemblies to support the building and achieve the natural concrete look. This was especially important to designers and the University to integrate the facility into the former industrial zone know as the Hayden Tract. The exterior walls were designed as concrete tilt-up panels with 2′-0″ “pillows” or half-circles on the exterior face. Special single-use form liners were designed and fabricated out of state to achieve the “pillow” shapes. Cast-in-place stitch columns were used to connect the tilt panels at each grid line. The stitch columns also used the “pillow-shaped” form liner but were exceptionally challenging because they were poured full-height (28′-10″) between the panels and had to line up perfectly with no gaps or visible seams. Largo Concrete’s in-house engineering team designed custom falsework to support lintel panels which would eventually be suspended 15’-0” in the air. These panels also feature the “pillowed” exterior finish and are unsupported from below as they span the openings to the building.
The interior frame of the building consists of cast-in-place walls, columns and ring beams: all exposed with an “as-cast” finish. Shotcrete walls and beams were installed against the existing building walls on two sides to connect the new construction to the existing building. As was the case with the exterior finish, no sacking or other cosmetic enhancements were allowed on the interior as well. The buildings roof is designed as a grid of vaults with curved glulam beams covered by roofing membrane, curved polycarbonate or nothing at all to allow for natural ventilation in certain spaces.
Limited access to the building pad because of the existing structure made it difficult to form, place and hoist the tilt-up panels. The time frame to complete all of the building concrete was 8 months. Despite these challenges the concrete scope of work was completed in eight months with zero safety incidents over 29,213 hours. Some of the potential hazards that were endured included 30’-0” shotcrete walls and beams, 30’-0” shear walls and columns, 30’-0” tilt-up panels and hoisting the panels with a high voltage wire running along one side of the jobsite.
Congratulations to the Culver City Creative (C3) team who helped us bring home the Charles Pankow, Jr. Award for “Outstanding Achievement and Excellence in Concrete Construction”! The annual award is given by the American Concrete Institute and recognizes outstanding and innovative use of concrete in construction.
About the Project:
Largo topped out at the Culver City Creative (C3) Office Tower and Parking Structure in January of 2017 with general contractor KPRS. Designed by Gensler and Saiful Bouquet, the commercial building stands seven levels tall with four mezzanine levels totaling 321,000gsf and is seeking a LEED Gold Certification. All the building concrete received an architectural finish and will remain exposed once complete. Typical levels are 14’ tall while decks with intermediate levels range from 22’ to 26’ between level seven and the roof. Six private balconies on the east and west sides of the building cantilever 11’6” out and are accessible through the large operable glass façade. Other unique structural elements include columns so large they are practically walls, aka ‘walumns’, and ring beams on the perimeter of the building at the mezzanine levels. The high-volume ceilings and available raw space allow 33,800sf decks to be easily expanded to 45,000sf with vertical and horizontal expansion options.
Access to the adjacent nine level, long-span parking structure is provided through two pedestrian bridges on the third and fifth levels allowing for private access to upper level offices. Designed by Parking Design Associates and Miyamoto International, this shear wall structure is two bays wide and will house 990 stalls across 326,741gsf. The pedestrian bridges connect to the structure on levels five and eight with the end-to-end helix structure providing 30 electric vehicle stalls and 50 bicycle spaces. The exterior features semi-opaque colored panels attached to the shear walls which refract sunlight back onto the structure creating an ever-changing façade throughout the day. All concrete on the parking structure remains exposed, including the elevator lobby. Largo poured 18,805CY of concrete in the office building and 10,874CY in the parking structure. The adjacent creative campus had to remain operational during construction and the biggest challenges came from protecting the existing parking structure and the cars inside of it.
Largo topped out at the Culver City Creative (C3) Office Tower and Parking Structure earlier this month with general contractor KPRS. Designed by Gensler and Saiful Bouquet the commercial building stands seven levels tall with 4 mezzanine levels totaling 321,000gsf. All the building concrete received an architectural finish and will remain exposed once the building is complete. Some unique structural elements include columns so large they are practically walls, aka ‘walumns’ and ring beams on the perimeter of the building at the mezzanine levels.
Adjacent to the office building is the nine level, long-span parking structure which also topped out this month. Designed by Parking Design Associates and Miyamoto Int’l this shear wall structure is two bays wide and will house 990 stalls across 326,741gsf.
Largo Concrete was recently awarded the Design-Build Parking Structure Expansion Project at Sony Studios in Culver City, CA. Located off Culver Blvd. the project includes two 6-level structures built on either side of the existing 5-level which will also receive an additional level of parking to match the two new adjacent structures. The entire project is 421,900sf with a total stall count of 1,357: 373-stalls in the East structure, 899-stalls in the West and 85 on the added level.
Our design team includes IDG Parkitects as Architect of Record and Ficcadenti Waggoner & Castle is the Structural Engineer. With construction scheduled to commence in August of this year, the design team is working out the final details of the structure with the Construction Manager, CW Driver and Sony Studios. The structures will be built consecutively, East then West, in order to keep the studio’s overall parking availability.
The existing structure utilizes a Shear Wall Structural System while both expansion structures will utilize a moment frame design. This is done to open up the structure to more natural light and ventilation and to provide a safer, light and bright pedestrian experience. The structure will be secured with metal screens around all openings on the ground floor and parking control equipment. The Art-Deco façade of the existing will be continued through the expansion structures and a basketball court will be installed on the roof deck of the east structure.