Our expertise and innovations include:
Coupled Girder Moment Resisting Frame (CGMRF) System – U.S. Patent 6,412,237B1
Uses two girders in each story to utilize ceiling sandwich depth (or the spandrel depth of the exterior wall) and couples them with two vertical couplers at one third of the span. The couplers stiffen the frame and absorb energy in earthquakes. This costs less to build and to repair in the event of an earthquake. On Moscone West, the use of the CGMRF system increased seismic safety while reducing steel cost by $2m.
Damped Structures – Friction/Viscous
Use of dampers reduces building displacements, floor accelerations and earthquake energy demand on the structural system. The added cost is 1-3% of the building cost. They are often used to enhance building performance to a level higher than the code mandated life safety goal.
Truss Moment Frames
Have been allowed in code for the past decade yet rarely used. We are involved in raising this system to a higher level of use. These trusses can support green building objectives by allowing more light into the building and improving design to have seismic yielding without permanent damage to the structure. Used in a high-rise project, they also contribute to the building design by avoiding the typical ‘office box’ look. The truss moment frame can be part of the exterior wall design.
Base Isolation
Our most current base-isolation project, the Cintamani Temple uses friction pendulum isolators to withstand major earthquake events on the nearby San Andreas Fault.
Long Span Structures
SDE’s use of long spans on buildings allows for architects vision for uninterrupted views and open spaces. Examples include the Golden State Warriors practice facility and Moscone West where 200 feet span spaces using high strength steel truss provided a 54,000sf column-free space.
Suspended Structures
Even though it seems counterintuitive at first glance, it is sometimes better to suspend a floor from the roof. In the Golden State Warriors Practice facility, we suspended the corporate offices from the roof trusses so that the floor framing could be shallow and loads delivered to the outside columns. This reduced the bending loads in the existing transfer girder of the convention hall, saving expensive upgrade of the convention center structure.
Performance-Based Design
As owners begin to realize the ability of state-of-the-art seismic design to save their building’s value in the event of a major earthquake, SDE’s influence in this area has led to upgrades in design criteria even on buildings that are not deemed Essential Facilities.