United States Department of Transportation
ROSA P serves as an archival repository of USDOT-published products including scientific findings, journal articles, guidelines, recommendations, or other information authored or co-authored by USDOT or funded partners.
As a repository, ROSA P retains documents in their original published format to ensure public access to scientific information.
i
Stainless Steel Strands and Lightweight Concrete for Pretensioned Concrete Girders (Final Report A – Stainless Steel Strands)
-
2020-12-01
[PDF-28.00 MB]
Details:
-
Creators:
-
Corporate Creators:
-
Corporate Contributors:
-
Subject/TRT Terms:
-
Resource Type:
-
Geographical Coverage:
-
Edition:December 2020
-
Corporate Publisher:
-
Abstract:Durability of prestressed concrete bridges in extremely aggressive environments is of increasing concern because of corrosion of the carbon steel strands. One solution to overcome the early deterioration of coastal bridges is to use corrosion-resistant strands, such as duplex high-strength stainless steel (HSSS) strands. The use of HSSS strands in flexural members has been hindered by the lack of full-scale test results and design guidelines. This report investigated the use of HSSS strands in flexural members. A total of thirteen (13) 42-ft-long AASHTO Type II girders were designed, fabricated, and tested in flexure and/or shear. Ten (10) girders were prestressed with HSSS strands, while the other three (3) were prestressed with carbon steel strands and served as control girders. This research program also included experimental activities to determine the mechanical and bond strength characteristics, prestress losses, and transfer length of 0.6- in-diameter HSSS strands. A stress-strain equation is proposed for the 0.6-in.-diameter HSSS strands. Experimental flexural and shear results showed that the post-cracking behavior of girders prestressed with HSSS strands continued to increase up to failure with no discernible plateau, which reflects the stress-strain behavior of the HSSS strands. In addition, flexural results revealed that, although HSSS strands have low ductility and all composite girders failed due to rupture of strands, the girders provided significant and substantial warning through large deflection, as well as well-distributed and extensive flexural cracking, before failure. Although the developed analytical model gave better predictions, the developed iterative numerical approach is slightly conservative and is easier to use for design – designers prefer to use an equation type of approach to perform preliminary designs. Therefore, equations were developed to calculate the nominal flexural resistance for flexural members prestressed with HSSS strands. Flexural design guidelines were proposed for the use of HSSS strands in flexural members. For I-girders, rupture of strands failure mode is recommended by assuring that concrete in the extreme compression fiber reaches considerable inelastic stresses, at least 0.7??c'. For beams (e.g., Florida Slab Beam), crushing of concrete failure mode is recommended by assuring that the net tensile strain in the HSSS strand is greater than 0.005. The recommended maximum allowable jacking stress and stress immediately prior to transfer are 75% and 70%, respectively. A resistance factor of 0.75 is recommended for both rupture of strand and crushing of concrete failure modes. AASHTO equations conservatively estimated the measured transfer length and prestress losses of 0.6-in.-diameter HSSS strands. The ACI 318-19 and AASHTO LRFD conservatively predicted the shear capacity of concrete girders prestressed with HSSS strands.
-
Format:
-
Funding:
-
Collection(s):
-
Main Document Checksum:
-
Download URL:
-
File Type:
