Steamboat Slough Bridge 529/20W


Systems Interface is experienced in the design, manufacture and commissioning of moveable bridge control systems. Our team is familiar with the design requirements as set forth by the American Association of State Highway and Transportation Officials (AASHTO) for moveable bridges.

Our experience also applies to AASHTO Movable Bridge Inspection, Evaluation and Maintenance requirements. We have conducted many In-Depth Bridge Inspections for the Washington State Department of Transportation (WSDOT).

Systems Interface is an industrial control panel manufacturer of UL-508A and UL-698a and ICP’s for hazardous locations listed control panels. Our licensed, Professional Engineers have extensive knowledge related to National Electrical code and hazardous area control requirements. We work with many city and district agencies to assure that their control systems meet Federal, State and local electrical codes.

Systems Interface Inc. has designed, manufactured, programmed, commissioned and maintained drive and control systems for not only moveable bridges, but also high Inertia/overhauling loads and heavy moveable structures such as rocket launch systems, antennas, radar domes, and telescopes throughout our company’s 30 year history.

Systems Interface Inc. is a licensed Professional Engineering Corporation in the State of Washington.

The following is an overview of recent bridge projects:

South Park Bridge, Seattle Washington, August 2014

On June 29th, 2014 the King County Department of Transportation celebrated the grand opening of the South Park Bridge, which is a new movable bascule style bridge over the Duwamish Waterway in Seattle, Washington. The Electrical Control Systems for the new bridge were designed, manufactured and commissioned by Systems Interface Inc.

The primary movers on the bridge were four (4) 100HP Motors operating in a torque share mode. The control solution was a Rockwell Automation ControlLogix®PLC, a Panelview HMI, a custom Allen-Bradley Motor Control Center (MCC) and Rockwell Automation PowerFlex DC Drives.

SR520 Floating Bridge, Lake Washington, Seattle, Washington, September 2013

The SR520 Floating Bridge spans Lake Washington in Seattle, Washington. This project is a Bridge Alarm Leak Detection Monitoring system for all the floating bridge concrete pontoons, medium voltage power stations, smoke detectors, Cathodic Protection System. It also controls the bridge lighting, navigation lights and walkway lighting. The Primary control components consists of a Rockwell Automation ControlLogix®PLC system with Panelview HMI terminals utilizing a redundant Ethernet Protocol over a fiber optic network.


Lacey Murrow Floating Bridge

Systems Interface designed,manufactured, programmed and commissioned the Lacey Murrow Floating Bridge Leak Detection and Monitoring System. This bridge has a Dupline two-wire network that extends over the two mile long bridge. It monitors the leak detection sensors in the pontoons, smoke detectors and lighting circuit status.

Mountlake Bridge Rehabilitation Project

Systems Interface designed, manufactured, programmed and commissioned a new bascule bridge control system, which included a new DC motor drive system. The bridge is critical for commuters to the University of Washington area.

The project also integrated the control of traffic gates and lights, channel lights, load limits, trunnion limits, and the drive motors operating both the North and South bridge leafs. The original 75 year old series wound 65HP DC motors were reused in the new system.

Systems Interface accomplished the rehabilitation by operating the existing series wound motors in a separately excited shunt configuration using a current controlled high ampacity DC supply to separately excite the series fields. This conversion enabled the use of industry standard armature DC/SCR drives and allowed the WSDOT to have the required control of speed and movement of the bridge when raising and lowering each leaf.

The DC motor drives consist of two leaf drive/control systems. One system controls the South bridge leaf and the other system controls the North bridge leaf. The North and South leaf drive systems are virtually identical. Each leaf drive cabinet houses two Siemens 75 HP DC four quadrant (reversing/regenerative) digitally controlled SCR motor drives, isolation transformers, tachometers, overspeed switches, limits interface, brake interface and logic/sequence controllers to interface between the motor drives and the bridge control system.