Vertical shear resistance of Composite Steel Truss in Concrete (CSTC) beams in fire: Pull-out tests and numerical analyses
Year: 2025
Type: article
Abstract: The present study introduces a special experimental setup for investigating the anchorage resistance of the diagonal of Composite Steel Truss and Concrete (CSTC) beams at elevated temperatures involved in the vertical shear resistance. The experimental campaign comprised four pull-out tests wherein each specimen was subjected to standard ISO 834–1 fire conditions and a constant load on the diagonal web bar. The observed failure mode in the tests indicated that the pulling resistance is limited by the fracture of the bar occurring near the bottom weld seam, resulting from the heat-degraded mechanical properties of the material. To further expand the experimental findings, finite element (FE) models were developed and validated against the test results via heat transfer and thermomechanical analyses in terms of temperature measurements and steel-concrete slip displacements. The numerical model was subsequently used to establish a benchmark data pool for verifying the suitability of the proposed method to predict the anchorage resistance of the diagonal web bar of CSTC beams in fire. This approach calculates a reference temperature defined at the expected fracture surface via heat transfer analyses. The resulting temperature-dependent yield strength is ultimately considered for the steel component of the vertical shear resistance, which cannot exceed the resistance of the diagonal concrete strut, in accordance with the strut-and-tie model.
Source: Engineering Structures
Institutions: ETH Zurich, Institute of Structural Engineering
Language: English
Subfield: Civil and Structural Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,620
OpenAlex ID: W4413499056