Calculation of Crack Width of Steel-Concrete Composite Beam Prestressed with Internal Tendons

Abstract

Steel-concrete composite beam prestressed with internal tendons (SCCPIT) is composed of prestressed concrete slab, steel beam and shear connectors, etc. At present, there is no calculation formula for crack width of SCCPIT in current design codes like European standard Eurocode 4 or American code ASSHTO LERD Bridge Design Specification (2004). In this paper, calculation formulas for crack width of nonprestressed steel-concrete composite beam provided in Code for Design of SteelConcrete Composite Structure (DL/T 50851999) were adopted as a basis for modification. On the basis of available test results, calculation formulas for uneven coefficient of reinforcement strain and average crack space were modified by consideration of concrete slab width and combined force ratio. Hence, empirical calculation formulas for crack width of SCCPIT under negative moment were proposed. In order to verify accuracy of proposed formulas, available test results including results of five simply supported SCCPITs previously conducted by author were introduced, and comparisons indicated that calculated values were in good agreement with test results.