THE DESIGN PROCESS

General Design Process

• Need– Determine functional requirements…

• Specification– Identify essential problems […]– Search for … solution principles– Combine and refine concept variants– Evaluate against technical and economic

criteria.

General Design Process

• Concept– Develop preliminary configurations– [Perform] introductory analysis– Select best preliminary design […]

• Preliminary Design– Refine and complete configuration(s)– Perform detailed analysis of refined design(s)– Prepare preliminary [specifications]

General Design Process

• Definitive Design– Finalize details– [Complete] final analysis and verification– Complete detail drawings […]

• Documentation• Prototype• Test and evaluate

– From G. Pahl and W. Beitz Engineering Design, The Design Council, Springer-Verlag, NY, 1984.

Structural Design Process

• Conceptual design– Layout (location, size, shape, spans)– Materials (steel, concrete, masonry, timber)– Performance requirements– Cost estimates

Structural Design Process (cont.)

• Preliminary Design– Layout framing– Rough sizing of members & foundation– Interaction with mechanical, electrical, etc.

Structural Design Process (cont.)

• Final Design– Detailed analysis– Final member sizes– Preparation of bid documents

• Inspect and review construction process.

Red River Wildlife Management Area

Needs:

• Span two bridge sites

• Movable to other locations

• Possible to construct with 2-4 men

• Aesthetically pleasing and non-intrusive

• No permanent foundation

Specification

• Minimum span of 80 feet

• Accommodate all terrain vehicles

• Snow load/pedestrian load of 100 psf

• Satisfy ADA

Concept: Two-Stage Launch

Tied-Back Segmental Construction

Fully-Assembled Launch

Preliminary Design: Truss Bridge

Preliminary Analysis

• Plan View– Pedestrian Load on Handrail