Project Highlights

• Dramatic porte cochere entrance to hotel complex
• Seismic design in high risk region
• Risa 3D dynamic analysis of the structure
• Revit and Risa software linkage

Overview

The freestanding porte cochere makes a dramatic entrance to the five-story Sheraton Desert Cove hotel, a resort facility that includes 300 rooms, luxury suites, a fitness center and spa, restaurant, pro shop, and underground golf cart storage area. The hotel central courtyard is designed for swimming, water play, and poolside activities with its covered arcades, fabric shade structures, fire pits, zero-entry pool, water slide, and other water play features.

Because of it’s proximity to the San Andreas Fault trace, the hotel complex is subdivided into three wings by seismic separation joints to increase seismic performance. Seismic joints are also used to separate the hotel’s main building from the restaurant, pro shop, and porte cochere, which are each independent one-story structures. Post-tensioned flat slabs are used for floors and roof throughout the complex and ductile reinforced concrete shear walls make up the lateral system.

The 45,000 square foot conference center is also a separate one-story, structural steel building with a steel-braced frame lateral system. Inside are generous spaces for both large and small gatherings as well as the main hotel kitchen, storage spaces, administrative offices, and a central plant and loading dock.

One of the project’s main challenges was to adequately support the complex architectural design elements, such as the porte cochere, in an area with such a high seismic risk factor. A rigorous structural peer review process was conducted on the project and value engineering was an ongoing process throughout its duration. Another difficulty was establishing the link between the Revit model and Risa engineering software, however, when successfully linked the result was greater efficiencies for the project. The modeling software made structural options and iterations easier and more accurate as MBJ worked within the parameters of the construction budget, strong seismic performance, and architectural vision.

In addition to providing typical services, MBJ also furnished a linear elastic dynamic response spectrum analysis for the hotel. The response spectrum used to establish seismic demand was based upon research of coefficients published by the USGS for regional seismicity in California. Short of a non-linear time history analysis, this is the most sophisticated method currently available for the analysis and design of lateral systems for building structures. It allowed us to optimize foundation sizes and reinforcing patterns for both foundations and shear walls.