碳纤维与钢板复合加固钢筋混凝土梁裂缝的试验研究

通过1根原梁、3根碳纤维与钢板复合加固梁和3根碳纤维加固梁的受弯性能试验,研究碳纤维与钢板复合加固钢筋混凝土梁的裂缝发展机理及裂缝宽度计算方法。研究表明,加固梁的裂缝间距和裂缝宽度均小于原梁,但次生裂缝有所增加;复合加固梁的裂缝发展速度比碳纤维加固梁缓慢,说明复合加固的限裂作用优于碳纤维;随着负载的增加,加固梁裂缝的发展速度加快,限裂作用随之减弱,最大裂缝宽度曲线出现突变,说明负载降低了加固的限裂作用,但负载对复合加固限裂作用的影响比碳纤维加固小。基于传统裂缝计算理论,引入复合加固粘结作用相关系数和负载影响系数,推导出考虑复合加固粘结作用及负载影响的复合加固梁裂缝宽度计算式。该公式的计算值与试验值吻合较好,计算方法简便,可用于工程设计。

Experimental Research on the Cracking Behavior of Reinforced Concrete Beams Combination Strengthened with Bonded CFRP and Steel Plate

Through the flexural test of one reference beam,three combination strengthened beams and three CFRP reinforced beams,the cracking mechanism and the calculation of crack width of reinforced concrete beams combination strengthened with bonded CFRP and steel plate were studied.Study shows that the crack distance and crack width of strengthened beams are less than those of reference beams,but the secondary crack has increased.The crack growth rate of combination strengthened beams is slower than that of CFRP reinforced beams,which illustrates that combination reinforcement is better than CFRP reinforcement in the role of limiting crack.With the increase of service loading,the crack development speed of reinforcement beams accelerates,and the effect of limiting crack will reduce with it.The maximum crack width curve also appears mutations,which explains that service loading has reduced the effect on limiting crack.However,the service loading has less role of limiting crack on combination reinforcement than CFRP reinforcement.On the basis of traditional crack calculation theory,the adhesive correlation coefficients of combination strengthening and the influence coefficient of service loading are introduced to derive the formula for calculating the crack width of combination strengthened beam considering service loading and adhesive correlation coefficients.The calculation result of crack width is in good agreement with test result.The calculation method is simple and convenient and can be applied to engineering design.