C60全珊瑚海水钢筋混凝土梁的抗剪性能与计算模型

Shear behavior and calculation model of C60 coral aggregate reinforced concrete beam

摘要:

为研究全珊瑚海水钢筋混凝土梁(coral aggregate reinforced concrete beam,CARCB)的抗剪性能和计算模型,设计了7根不同种类钢筋的CARCB,通过对其进行斜截面抗剪性能试验,研究了钢筋种类对CARCB的变形及抗剪承载能力的影响,建立了弯矩-跨中挠度、荷载-钢筋应变、荷载-裂缝宽度的关系,提出了CARCB斜截面抗剪承载力的计算模型.试验结果表明:不同种类钢筋CARCB的正截面开裂荷载和抗剪承载力规律均为316不锈钢＞普通钢筋＞锌铬涂层钢筋＞有机新涂层钢筋；CARCB中普通钢筋发生了严重锈蚀,使其刚度出现了一定程度的退化；不同种类钢筋的CARCB,其裂缝宽度均随着荷载的增大而增长,加载初期,在梁跨中附近出现正截面弯曲裂缝,裂缝宽度开展非常缓慢,随着荷载的增加,在支座向集中力作用点处出现斜裂缝,斜裂缝宽度迅速增大,最终导致梁破坏；最后,综合考虑钢筋锈蚀和高强混凝土对CARCB抗剪承载力的影响,提出了更加合理的CARCB抗剪承载力计算模型.

Abstract:

Seven coral aggregate reinforced concrete beams (CARCBs) with different types of reinforcement were designed in this study to investigate their shear behavior and calculation model. The shear behavior of CARCB was tested, and the deformation and shear capacity were investigated. The relationships of bending moment-midspan deflection, load-steel strain, and load-crack width were established. A calculation model for the ultimate bearing capacity (V_cs) of CARCB was proposed. Results show that normal section cracking load (V_cr) and V_cs of CARCB followed the rule: 316 stainless steel > common steel > zinc-chromium coated steel > organic new coated steel. The common steel had serious corrosion in the CARCB, which led to the degradation of stiffness. The CARCB crack width increased with the increase of load for different reinforcement types. In the initial loading stage, flexural cracks occurred at the midspan of the beam, which developed slowly. Inclined cracks were formed from the support to the concentrated force point with increasing loads, which widened rapidly, leading to beam failure. Therefore, with comprehensive consideration on the effects of reinforcement corrosion and high-strength concrete on the V_cs of CARCB, a calculation model for the V_cs of CARCB was proposed.