Shotcrete Archives | Page 17 of 17

Solution

A city’s history can be told by its venerable buildings that still stand. Over time even the best built buildings succumb to time and stress. Some buildings are worth saving, but cost prohibitive. Retrofit construction costs can often exceed a budget and doom a building. The Hall of Justice renovation project in Los Angeles could have been halted if a cost-effective solution was not designed.

Massive strengthening was necessary to save the 1925-built Hall of Justice. New 24-inch thick shear walls, hammerhead-shaped boundary elements, and drag beams were critical pieces needed to save the ailing structure. These new concrete members will be joined to the existing structure by anchoring approximately 52,000 drill and epoxied dowels.

Conventional methods of placing this concrete would require that forms be erected, adding both time and cost to the project. Additional hurdles would include form material storage, and crew movement through the thirteen building levels. With all of this complexity, it became apparent that pneumatically placed concrete, also known as shotcrete, was the ideal placing method. Shotcrete will allow the construction team to almost eliminate the forming process all together. Once the reinforcing has been installed, the shotcrete can be placed. Furthermore, because shotcrete is placed without a form there are no concrete consolidation surprises.

The Hall of Justice’s structural retrofit would not have been economically possible without the use of shotcrete. Conco’s efforts during the design, its ability to execute, its robust tool set, and immense experience may have given The Hall a new lease on life. Contact us for more information on how we can save or improve your next project.

Follow the progress of The Hall of Justice at CalrkHallofJustice.com.

Looking for a Faster, Economical Solution?

A new parking structure being constructed in Santa Clara, CA offered challenges similar to many other projects. The owner and the general contractor, Devcon Construction, were looking for ways to get the structure built more quickly and economically. One solution used was to build the 40 feet shear walls using the shotcrete method as opposed to being cast in place.

The project, Lawson Lane Commons, has shear walls spanning 310 lineal feet and 40 feet high. Foundations for the walls were poured on 5/25/2012 and three separate shotcrete pours were done with the final shoot being completed on 6/28/2012. In total, 390 cubic yards of concrete were shot and the walls were completed in only 25 working days.

In reviewing this project, our estimators projected that comparable cast-in-place walls would have taken 24% more man hours to complete. The additional man hours would have equated to higher labor costs and several more days on the schedule to complete the task. By using shotcrete provided by Conco, the general contractor was able to have the shear walls completed in less time than anticipated, saving time on the overall schedule. Furthermore, the shotcrete walls have the same structural characteristics as traditional cast-in-place walls.

Shotcrete is a method of applying concrete pneumatically through a high pressure nozzle. Because it is installed at a high velocity, shotcrete tends to have better consolidation than conventional concrete, making for a denser finished product. The consistency of shotcrete is more easily controlled than cast-in-place concrete as it is impossible to place high water/cement (w/c) ratio shotcrete. As a result, characteristics of low w/c concrete are found in shotcrete, including increased durability and reduced shrinkage cracking. Shotcrete is subject to the same design factors as conventional concrete; therefore, the strength characteristics desired in poured-in-place concrete can also be achieved in shotcrete walls.

Shotcrete offers not only excellent structural properties, but also provides economical advantages over typical cast-in-place concrete. With reduced forming, shotcrete walls can be constructed faster with less material, saving our client both time and money. The absence of tie holes (that need to be filled, leaving visible blemishes) and the ability to easily apply color, stains, and textures makes shotcrete an aesthetically appealing alternative.

Conco operates shotcrete crews in Washington, Northern California, and Southern California. All operators are ACI certified, have years of industry experience, and demonstrate excellent craftsmanship. Our professional estimators can assist you in comparing the time and cost differences of shotcrete walls versus conventional cast-in-place concrete for your specific project. Should you need assistance, please call Chad Watson at 925-685-6799.

Problem: Unappealing Concrete Shear-wall

Solution: Sculpted Shotcrete Mural

The City of Burien, WA sits below the Cascade Mountain range. As such, in the background of the downtown area is Mount Rainier. When building a parking garage to support the bus transit center, the city wanted to avoid having a structure with stark concrete walls. Their goal was to turn the building into a piece of art that highlighted the city’s most visible landmark and surrounding mountain ranges.

Working with the general contractor, Pankow Builders, Conco worked to create sculpted shotcrete murals that depicted views of the Cascades, Olympics, and Mount Rainier on all four sides of the building. The shear-walls were shot from the outside of the building and the area’s where the murals were going to be located were left with a scratch finish to allow the proper bonding of the mural work to the structural shotcrete wall.

As the picture shows, the shotcrete murals provide not only the structural integrity needed for the parking structure but serves as a stunning work of art that highlights the local landscape of Burien, WA.

The application of sculpted shotcrete is only limited by the imagination. It is a great way to either highlight your structure or blend it in with the local landscape.

Click the gallery images below for a closer look.

For more information on sculpted shotcrete contact Chad Watson at 925-685-6799.

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