The Post-tensioning Institute recently commissioned Dennis Reilly, SE to present his innovative work in Sustainable Design at their National Conference in Fort Worth, Texas.
At POSTEN Engineering Systems, Dennis Reilly developed procedures whereby the Post-tensioning Software, POSTEN Multistory, automatically determines the thinnest section of concrete & the least amount of steel to create the most efficient design possible, completes the design and then automatically produces documentation required for LEED certification.
In Sustainable Concrete Design, the conversation usually starts with Fly Ash or Building Durability and then goes quiet.
In Sustainable Steel Design, the conversation usually starts with the use of Recycled Steel and then, again, goes quiet.
The use of Fly Ash and Recycled Steel is not new, and with the increasing costs of Cement and Steel, their use will expand whether or not Sustainable Design is important or not. In many cases, Fly Ash improves the performance of the concrete from installation to long term durability. With the exception of Specifying the use of Recycled Steel, the use and acquisition of Recycled Steel is mostly outside the control of the Design Structural Engineer. In any regard, Dennis believes that using materials that you would use anyway is not truly Sustainable Design.
In Structural Engineering, Dennis believes that Sustainable Design demands more - Efficient Design. Even though Post-tensioned Structures use significantly less steel & concrete than Conventionally Reinforced Concrete structures, they still tend to be extremely in-efficiently designed, since they are often designed using inefficient & time consuming Trial and Error Methods.
Dennis demonstrated Automated procedures that could save an inch of concrete thickness and 9% in steel in a typical post-tensioned slab, while improving the performance of the structure & documenting the savings for LEED.
Dennis then presented the concept of Post-tensioned Moment Frame Design (only capable on POSTEN Multistory), which further Expands Sustainable Design by removing the need for shear walls (opening up the building).
Dennis believes that , just as Energy Efficient Radiant Heat also provides the most comfortable heating system, Efficient Sustainable Post-tension design should and can expand the volume of the building or reduce the building height, reduce the building weight and enable the Architect’s creativity, while also REDUCING the cost of construction.