活性粉末混凝土拱极限承载力试验研究

EXPERIMENTAL RESEARCH ON THE ULTIMATE LOAD CAPACITY OF REACTIVE POWDER CONCRETE ARCHES

进行了两根活性粉末混凝土（RPC）模型拱的L/4处单点加载的面内受力全过程试验,建立了考虑材料与几何双重非线性的有限元模型,有限元计算结果与试验结果吻合良好。通过与普通混凝土（RC）模型拱的受力性能的比较,对RPC模型拱荷载-竖直位移曲线、裂缝开展情况、截面应变和结构破坏模式等方面进行了分析。试验与有限元计算结果表明,RPC拱受力过程和破坏模式与RC拱相似,分为弹性阶段、裂缝开展阶段和钢筋屈服阶段,最终因出现4个塑性铰形成机构而呈塑性破坏,其极限承载力也可用极限分析法进行简化计算。RPC拱由于其材料性能优越,使其受力性能优于RC拱,在同级荷载下RPC拱裂缝的宽度约为RC拱的25%~50%;而RPC拱的开裂荷载、钢筋屈服荷载和极限承载力均较RC拱有明显的提高。在极限承载力相同的条件下,RPC拱的截面积与自重可以减小到RC拱的67%左右,表明RPC可有效减轻结构自重,提高拱桥跨越能力。

Experiments on two reactive powder concrete （RPC） model arches subjected to concentrated loads at quarter-span have been carded out. A finite element （FE） procedure considering both material and geometric nonlinearities is developed and the numerical predictions agree well with the test results, The load-displacement curves, cracks, strains, failure modes and ultimate load capacities of the arches are analyzed and compared with the results of conventional reinforced concrete （RC） model arches. FE analytical and experimental results show that the RPC arches behave similarly to RC arches. The RPC arches also fail due to the mechanism formed by four plastic hinges caused by cracks in tensile areas. The ultimate load capacity of RPC arches can be estimated by the limit analysis method, similar to RC arches. It is concluded that RPC arches have greater load capacity, stiffness and anti-cracking resistance than those of the RC arches owing to the superior properties of RPC. The widest crack in RPC arches is only 25%N50% that of RC arches under the same load. At a same load level, the cross section area and self-weight of the RPC arch can be about one third less than those of the RC arch, indicating that the application of RPC would improve the spanning capability of arch bridges.