土木工程畢業(yè)設(shè)計外文翻譯-展示頁
2025-01-25 11:50本頁面
【正文】 has no apparent effect on the overall behaviour of the structural forms investigated ( [2], [3]). If such behaviour is typical for any structure, then the large pressivestrains (in excess of ) measured on the top surface of a reinforced concrete beam at its ultimate limit state (see fig. 1), cannot be attributed to postultimate uniaxial stressstrain characteristics. Furthermore, since the pressive strain at the ultimate strength level of any concrete under uniaxial pression is of the order of (see fig. 2), it would appear that a realistic prediction of the beam response under load cannot be based solely on the ascending portion of the uniaxial stressstrain relationship of concrete.In view of the above, the work described in the following appraises the widely held view that a uniaxial stressstrain relationship consisting of an ascending and a gradually descending portion is essential for the realistic description of the behaviour of a reinforced concrete beam in flexure. Results obtained from beams subjected to flexure under twopoint loading indicate that the large strains exhibited by concrete in the pression zone of the beams are due to a triaxial state of stress rather than the uniaxial postultimate stressstrain characteristics of concrete. It is shown that the assumption that the material itself suffers a pleteand immediate loss of loadcarrying capacity when ultimate strength is exceeded is patible with the observed ductile structural behaviour as indicated by loaddeflexion or momentrotation relationships.2. EXPERIMENTAL DETAILS. SpecimensThree rectangular reinforced concrete beams of 915 mm span and 102 mm height x 51 mm width crosssection were subjected to twopoint load with shear spans of 305 mm (see fig. 3). The tension reinforcement consisted of two 6 mm diameter bars with a yield load of kN. The bars were bent back at the ends of the beams so as to provide pression reinforcement along the whole length of the shear and tension reinforcement along each shear span were linked by seven mm diameter stirrups. Neither pre
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