低速冲击下钢筋混凝土梁局部变形刚度

研究了低速冲击下钢筋混凝土梁的截面刚度,以及冲击体和结构间接触区域的柔度变化.将梁分成斜裂缝形成以前和斜裂缝形成以后两个阶段来研究.斜裂缝形成以前,梁被看成弹性均质体,接触区的柔度由受压和受拉条件下混凝土的柔度串联而成,根据柔度的定义推导得出该阶段接触区的刚度;斜裂缝形成以后接触区的刚度受高为χw弯—剪式固端梁构件、下部受拉钢筋、冲击体与下部钢筋之间的混凝土柱的制约,从而推导出该阶段的柔度.结合两个阶段接触区域的柔度公式,对低速下钢筋混凝土梁的接触刚度进行了举例计算和分析,表明斜裂缝形成以前的阶段可以忽略不计.

Local deformation r ig id ity of re inforced concrete beam under low ve loc ity mi pact

Sect iona l rig id ity o f rein fo rced co ncre te beam under low ve locity im pact and f lex ib le st if fne ss o f con tact reg ion be tw een the im pac t body and st ructu rew erem ain ly studied. T he beam w as d iv ided in to tw o stag es be fo re and af ter the ob lique crack. T he beam w as con sidered an ela stic body, the de f lec tion o f the con tact reg ion w as com po sed o f def lect ions o f the concrete in pre ss and tension, and the rig id ity o f con tact reg io n in th is stage w as deduced acco rd ing to the def in it ion o f the de f lection. T he r ig idity o f con tac t reg ion w a s co nstra ined w ith bend ing-shearing beam e lem en t o f xw , ten sion steel bar and the co ncre te co lum n betw een the im pac t body and the in fe rio r stee l bar, and the def lect ion o f th is stag e w as dedu ced. W ith the fo rmu la fo r f lex ib le st iffness o f the tw o stag es, the con tact ing st iffness o f the beam unde r low ve locity impact w ere com pu ted and ana ly zed by w ay o f ex am p le, and the conc lu sio n w as ob ta ined tha t the stag e be fo re the ob lique crack can be igno red.