‍USE THESE EXPERIMENTAL FEATURES WITH EXTREME CAUTION

UHPC is a relatively new material for precast, prestressed concrete bridge products. This material has been generally used for connections between adjacent precast members. Significant effort is underway in the precast industry to bring UHPC into the mainstream for precast bridge girder products.

UHPC features in this software are considered to be experimental. They are based on structural design guidance developed by PCI (1). The design guidance is based on research, international guidelines and testing. UHPC features are subject to change and may be removed at any time. They may be incomplete, inaccurate, and incompatable with guides, specifications, and research reports that have been published or may be published in the future.

The AASHTO LRFD Bridge Design Specifications are applicable for bridges with specified concrete strength up to 15 ksi . UHPC is a high strength material with specified concrete strength in the range of 18-22 ksi. The equations, procedures, recommendations, and other related information from the AASHTO LRFD Bridge Design Specifications are applied to UHPC concrete members. The applicability of the AASHTO LRFD Bridge Design Specifications to UHPC concrete members has not been verified or validated.

There are many potential benefits of UHPC precast, pretensioned concrete bridge components. UHPC can lead to smaller, lighter, and more efficient girders. Experimental girders made from UHPC have thinner webs and flanges, greatly reducing weight. Web and flange buckling are typically not a concern for traditional precast girders. Web and flange buckling, and other behavior related to thin members, are not evaluated. Additional analysis beyond the scope of this program may be required.

Because of fibers in UHPC, some tension capacity can be relied upon for shear strength. In some cases, UHPC girders can be constructed without shear stirrups. This translates to significant savings in labor and materials during girder fabrication.

‍Implementation of UHPC structural design guidance developed by PCI should not be construed as an endorsement of the methodology by Washington State and Texas Departments of Transportation. The UHPC features in this software are developed by the Washington State DOT and are a service to and indended to support the bridge engineering community at large as UHPC class materials evolve into common use. WSDOTs intentions are to implement other structural design guidance currently under consideration and ultimately provide implementation for a single, unified, approach to UHPC design based on any AASHTO guide specifications that may be published in the future.

References

1. Tadros, et. al., "Implementation of Ultra-High Performance Concrete in Long-Span Precast Pretensioned Elements for Concrete Buildings and Bridges, Phase II Report", PCI, September 2021

‍USE THESE EXPERIMENTAL FEATURES WITH EXTREME CAUTION