自然腐蚀环境下钢筋混凝土梁疲劳应用性能试验研究

在海岸与近海结构工程中被广泛应用的钢筋混凝土构件,由于长期处在有海水腐蚀、干湿交替和循环荷载的严酷环境中,导致钢筋因侵蚀结构严重损伤。本文对6根钢筋混凝土试验梁进行了腐蚀与循环荷载作用下的疲劳试验研究,循环荷载幅值设计为2%～40%P_u和2%～60%P_u两种,对试验梁在大气环境中、淡水环境中和海水腐蚀环境中疲劳破坏情况进行试验探索,研究在三种环境与循环荷载作用下钢筋混凝土构件的力学性能及刚度损伤演化规律,同时分析了破坏形态、裂缝宽度、挠度的发展规律和疲劳寿命。结果表明:腐蚀与循环荷载共同作用下,短期内腐蚀溶液不会对梁内部钢筋造成显著影响从而降低耐久性;在循环次数达到一定范围内,试验梁耐久性降低42%,其中两个试验梁在循环荷载上限为0.6P_u时的耐久性分别降低54%和37%。

Experimental Study on the Fatigue Performance of Reinforced Concrete Beams in a Natural Corrosion Environment

Nowadays, reinforced concrete components are widely used in coastal and offshore structural engineering. In harsh environments with seawater corrosion, dry-wet alternation, and extended cyclic loads, steel bar corrosion eventually leads to serious structural damage. In this paper, fatigue tests of six reinforced concrete test beams under corrosion and cyclic loading were carried out. Two kinds of cyclic loading amplitudes (2%-40% P_u and 2%-60% P_u) were designed, and fatigue failures in the atmospheric environment, freshwater environment, and corrosional seawater environment were studied. Mechanical properties and damage to reinforced concrete beams under three kinds of environments and cyclic loads, based on the evolution law of stiffness, were further explored. Failure mode, crack width, deflection development, and fatigue life were analyzed. Study results showed that under the combined action of corrosion and cyclic load, the corrosional solution did not significantly affect the internal reinforcement of the beam in the short term. Durability of the test beam as reduced by 42% within certain cyclic times, and durability of the two test beams were reduced by 54% and 37% when the upper limit of cyclic load was 0.6 P_u.