Field Experience and Structural Performance of Self-Consolidating Concrete in High-Rise and Bridge Construction-Structural Performance of Alabama’s First SCC Precast, Prestressed Girder Bridge (PDF)

Structural Performance of Alabama’s First SCC Precast, Prestressed Girder Bridge (PDF)

Pdf Summary

The research discusses the structural performance of Alabama’s inaugural Self-Consolidating Concrete (SCC) precast, prestressed girder bridge, aimed at assessing the feasibility of utilizing SCC in Alabama's precast, prestressed girder structures. Spearheaded by Sam Keske from Wiss, Janney, Elstner and professors from Auburn University, the study involved full-scale SCC implementation in in-service bridges for a comprehensive analysis of SCC’s performance compared to conventional concrete (VC).<br /><br />Seven 100-foot and 134-foot girder types, both SCC and VC, were fabricated and monitored over several months in various conditions, including pre-release, detensioning, and long-term after deck addition. Tests measured key factors like mechanical properties, transfer length, prestress loss, and responses to loads using vibrating-wire strain gauges and other equipment.<br /><br />Experimental results indicated that SCC's modulus of elasticity (Ec) was 5-15% less than VC's, as expected due to mixture differences. Despite these differences, SCC's tensile strength proved predictably similar to VC's and both materials exceeded design expectations. SCC transfer lengths were realized as somewhat over-predicted but within an acceptable margin which did not warrant model adjustments. <br /><br />Measurements highlighted SCC’s 30% higher free shrinkage compared to VC, but both materials’ long-term cambers and prestress losses were similar over 1,000 days. The live-load response showed that SCC and VC girders behaved nearly identically in real-world conditions, suggesting that concerns about SCC’s use in prestressed girders are unfounded.<br /><br />Conclusively, the in-service performance and the predicted versus specified results support SCC as a viable option for prestressed concrete girders due to its comparable behavior to VC, encouraging its broader implementation in similar applications.

Keywords

Self-Consolidating Concrete

SCC

Alabama

precast prestressed girder

structural performance

Auburn University

mechanical properties

modulus of elasticity

transfer length

prestress loss