Shear design expressions for concrete filled steel tube and reinforced concrete filled tube components.

Details

• Creators:
  Roeder, Charles ; Lehman, Dawn ; Heid, Ashley ; Maki, Todd
• Corporate Creators:
  Washington State Transportation Center
• Corporate Contributors:
  Washington (State). Dept. of Transportation. Research Office ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Columns
  • Vertical supports
  • Poles (Supports)
  • Shear strength
  • Concrete construction
  • Concrete Filled Steel Tubes
  • CFST
  • Shear resistance
• Publication/ Report Number:
  WA-RD 776.2
• Resource Type:
  Tech Report
• Geographical Coverage:
  Washington
• Corporate Publisher:
  Washington (State). Department of Transportation. Research Office
• Abstract:
  Concrete-filled steel tubes (CFSTs) and reinforced concrete-filled steel tubes (RCFSTs) are increasingly ; used in transportation structures as piers, piles, caissons or other foundation components. While the axial ; and flexural properties of CFTs have been well researched, research on their shear resistance is lacking. ; Currently accepted methods for calculating the shear capacity of CFSTs and RCFTs are adapted from ; shear strength equations used for structural steel or reinforced concrete components. Though, it is ; expected that CFSTs would retain the full shear capacity of the steel without local buckling of the ; section. In addition, because circular CFSTs provide optimum confinement to the concrete core, it is also ; expected that the full shear strength of plain or longitudinally reinforced concrete can also be developed. ; Since no equation currently accounts for both, it is probable that they significantly underestimate the ; effectiveness of the composite section, potentially increasing undesirable conservatism and cost. ; However, without experimental data to validate the design expressions, it is not possible to modify them. ; The research program described herein experimentally investigated the shear resistance and deformation ; of CFST and RCFST members with an eye towards developing an improved and more accurate shear ; strength expression. The experimental study included 22 large-scale CFTs subjected to four-point ; bending. The study parameters included: (1) the aspect ratio (a/D where a is the clear span from the point ; of loading to the point of support and D is the tube diameter), (2) concrete strength, (3) D/t (where t is ; the thickness of the steel tube), (4) interface condition (greased or contaminated with soil), (5) infill type ; (concrete or gravel), (6) internal reinforcement ratio, and (6) length of the tube beyond the support (tail ; length). The results indicate that the shear strength of CFSTs and RCFSTs is on average 2 times the ; current WSDOT expression. This new design expression for shear resistance has been proposed for ; implementation in the WSDOT Bridge Design Manual (BDM).
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• Format:
  PDF
• Funding:
  Agreement T1461, Task 04
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/31674/dot_31674_DS1.pdf
• File Type:
  [PDF - 4.36 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:cd5bee2284d88e95d9f796571aefe61e8577b9dfccc33d462ca0a685cff89e84