Modeling and Design

Analytical Modeling

Because of their bonded connection, hybrid steel-glass beams offer a specific bearing behavior that needs to be considered in analytical calculations. Hereby the load transfer mainly depends on the shear stiffness of the adhesive connec­tion. The size of the composite action between steel and glass specifies the nor­mal force that can be transferred to the steel flanges and thus defines the bearing capacity of the beam. Appropriate methods are based either on the sandwich theory [23] or on approaches according to Mohler [24] or Pischl [25]. Within the analytical investigations of INNOGLAST on bonded steel-glass beams, these three methods were modified (sandwich theory in Ref [26], Mohler or Pischl theory in Ref [27]) and used for the design of steel-glass beams. Especially, approaches according to Mohler and Pischl have been established for segmented wooden structures with flexible connections for years and have led to reliable results that are easy to calculate for practical applications. The basis of the

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Modeling and Design

FIG. 8—Comparison of the adhesives’ deformation behavior in block shear tests and large-scale component tests.

Mohler approach is the calculation of effective beam stiffnesses, whereas the Pischl method directly assigns the normal force to the flanges. The disadvantage of all simplified methods is the lack of knowledge of the detailed multiaxial stress distribution within the adhesive connection; here only smooth distributions result.