BFRP筋钢纤维高强混凝土梁受弯承载力试验与理论

Experimental and theoretical study on the flexural capacity of high-strength concrete beams reinforced with BFRP bars and steel fiber

  • 摘要: 通过11根玄武岩纤维增强聚合物复合材料(BFRP)筋钢纤维高强混凝土梁的受弯性能试验,研究了钢纤维混凝土层厚度、钢纤维体积分数和BFRP筋配筋率对BFRP筋钢纤维高强混凝土梁受弯破坏形态及其承载力的影响。结果表明,BFRP筋钢纤维高强混凝土梁的破坏模式可分为受压破坏、受拉破坏和平衡破坏3种;钢纤维混凝土层厚度和钢纤维体积分数的变化对于BFRP筋钢纤维高强混凝土梁受弯承载力具有一定程度的影响,当BFRP筋配筋率为0.77%时,掺加体积分数为1.0%钢纤维的梁受弯承载力较无钢纤维梁提高了22.7%,在受拉区0.57倍截面高度内掺加1.0vol%钢纤维的梁受弯承载力达到全截面钢纤维混凝土梁受弯承载力的86.7%;增大BFRP筋配筋量可显著提高BFRP筋钢纤维高强混凝土梁的受弯承载力,BFRP筋配筋率为1.65%的试验梁受弯承载力较配筋率为0.56%的试验梁提高了39.4%。针对不同的破坏模式,提出了BFRP筋钢纤维高强混凝土梁受弯承载力和平衡配筋率的计算方法,并结合安全配筋率的概念对试验梁的破坏模式进行了预测,试验结果与分析结果吻合良好。

     

    Abstract: In order to investigate the influences of depth of steel fiber reinforced concrete layer, steel fiber volume fraction and ratio of basalt fiber reinforced polymer(BFRP) bars on flexural capacity of high-strength concrete beams reinforced with BFRP bars and steel fiber, 11 specimens were cast and tested. The results indicate that there are 3 failure modes of high-strength concrete beams reinforced with BFRP bars and steel fiber:concrete crush, BFRP bars rupture and balance failure. The steel fiber reinforced concrete layer and steel fiber volume fraction have various influences on flexural capacity of specimens. When the BFRP reinforcement ratio is 0.77%, with the addition of steel fiber (the volume fraction was 1.0%), the flexural capacity can be increased by 22.7%; for the specimen with steel fiber volume fraction of 1.0% and steel fiber reinforced concrete layer of 0.57 times of the total depth of beam, the flexural capacity is 86.7% of that of the fully steel fiber reinforced specimen. Increasing BFRP reinforcement ratio is an effective way to improve the flexural capacity of BFRP bar and steel fiber reinforced beams, the flexural capacity of the specimen with BFRP reinforcement ratio of 1.65% is 39.4% higher than that of the specimen with BFRP reinforcement ratio of 0.56%. Based on the experimental and theoretical analysis, a calculating method, which can be used for evaluating the failure mode and flexural capacity of high-strength concrete beams reinforced with BFRP bars and steel fiber, was proposed. The calculated values have good agreement with test results.

     

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