RESEARCH ON FLEXURAL PERFORMANCE OF DOUBLE-STEEL REINFORCED CONCRETE BEAM

A new type of steel concrete composite beam with double-joist steel sections encased was introduced． Six large-scale specimens were designed and tested under four-point bending condition to study the performance indicators of normal section bending bearing capacity，deformation，ductility and ultimate curvature and ultimate bending moment． It was found that the double-steel reinforced concrete beam had high strength and well ductility． The cracking load and ultimate load of the beam were influenced by the steel ratio，rebar ratio，stirrup ratio，steel size，space，and shear studs． Based on the comparison of the test results and through correcting coefficient of concrete part and the whole part in two Chinese codes，the bending calculation formula of double-steel reinforced concrete beam was obtained．