Experimental Research On Flexural Mechanical Behavior Of Simple Prestressed H-steel Reinforced Concrete Beam

Simple prestressed H-steel reinforced concrete beam is a new style of composite beam that lay and tension reasonable prestressing tendon in the clear height of H-steel. The composite beam has many strongpoints of steel structure, concrete structure and prestressed structure, high stiffness, big carrying capacity, small deformation, small crack width, small section size, and good seismic behavior. This composite beam can be used both in regularly new projects and as main or secondary girder in the story-adding and upgrading of existing building structures, also as frame beam or secondary beam of huge frame building structure.Compared to H-steel reinforced concrete composite beam, prestressed H-steel reinforced concrete beam has its own characteristics. Study on its bearing capacity calculation, crack and deformation has not been reported. According to these problems, finished the test of five simple prestressed H-steel reinforced concrete beams and accumulated valuable test date.Through analysis of test data, draw the conclusion that strain of section accords with plane section assumption in the loading process of simple prestressed H-steel reinforced concrete beams. On the basis of which derived bearing capacity calculation formulas of normal section which go with test date.In allusion to that bonding power is lower between H-steel and concrete, realized the correction of calculation of average crack intervals of simple prestressed H-steel reinforced concrete beam though introducing a reduction factor of bond behavior. The value of influence factor of elongation of concrete to crack width between cracks was calculated through analyzing test data, so the calculation formula of the average crack width of simple prestressed H-steel reinforced concrete beam was obtained; the magnification factor showing the ununiformity of crack width was got by fitting crack distribution frequency diagram. At last, calculation formula of crack width of simple prestressed H-steel reinforced concrete beam was brought forward.Based on the test of five simple prestressed H-steel reinforced concrete beams, the situation of deformation was studied and calculation formulas of stiffness were presented. The stiffness of simple prestressed H-steel reinforced concrete beam equals to the summation of the stiffness of prestressed concrete beam and that of H-steel beam.