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Cover of Strengthening-By-Stiffening: A New Concept for Strengthening Sheardeficient Thin-walled Steel Girders
Strengthening-By-Stiffening: A New Concept for Strengthening Sheardeficient Thin-walled Steel Girders
  • Publication no: ABC2017-020-17
  • Published: 20 April 2017

Strengthening-By-Stiffening (SBS) is a new concept developed to enhance the strength and performance of shear-deficient thin-walled steel girders. In SBS, pultruded composite sections are bonded to buckling prone web panels to serve as stiffeners.

SBS has many advantages including eliminating the need for in situ welding especially transverse welds, light weight and ease of application. An extensive experimental program has been completed to study the effect of different parameters on the efficiency of SBS. These parameters include adhesive type, slenderness ratio, and stiffener configuration.

This paper presents results from the experimental program, which showed that gains in shear strength of up to 51% using glass fiber reinforced polymers (GFRP). The SBS is further explored as a means for fabricating new steel girders that are free from transverse welds. This transverse weld free (TWF) concept is achieved by replacing all bearing and transverse steel stiffeners with bonded GFRP stiffeners. A numerical investigation is conducted for that purpose using a validated finite element model. Interface debonding between the steel and FRP surfaces is modelled using a cohesive zone material. The model also takes into account material and geometric nonlinearities in addition to delamination within the FRP stiffener layers.

Results showed promise for the ability to build TWF girders, which is known to have a better fatigue life.