配筋梯度混凝土梁裂缝宽度实用计算方法  

Flexural crack width calculation method for reinforced gradient concrete beams of normal and high strength concrete

作　　者：周威[1] 郑文忠[1] 

机构地区：[1]哈尔滨工业大学,黑龙江哈尔滨150090

出　　处：《土木工程学报》2011年第12期42-49,共8页China Civil Engineering Journal

基　　金：黑龙江省自然科学基金(E200835);哈尔滨工业大学优秀青年教师培养计划(HITQNJS.2008.040)

摘　　要：截面压区采用高强高性能混凝土、拉区采用普通混凝土的配筋梯度混凝土受弯结构构件,可充分利用抗压强度高的高强高性能混凝土及经济性好的普通混凝土优点,实现二者有机结合。试验表明拉区普通混凝土初凝前将压区高强混凝土浇筑完毕,有利于保证强度差异较大的异强混凝土中的水泥浆几乎同时开始水化,在硬化并达到设计强度后,两类混凝土可协同整体工作,验证了所构建的配筋梯度混凝土梁的有效性和可实施性。以承载能力极限状态控制截面相对受压区高度为基本参数,开展拉压区为异强混凝土的配筋梯度混凝土简支梁的受弯性能试验基于截面应力应变分布规律,提出该类矩形截面受弯构件开裂前瞬时受压区高度表达式与建议取值,按截面应力应变法和塑性影响系数法获得开裂弯矩表达式。基于试验结果,提出该类受弯结构构件平均裂缝间距、平均裂缝宽度以及最大裂缝宽度实用计算方法。为配筋梯度混凝土受弯构件正常使用极限状态分析创造了基本条件。The compressive zone of the section of the reinforced gradient concrete beams is made of high strength concrete, and the tensile zone of normal strength concrete. The merits are achieved with higher compressive strength of high strength concrete and low cost of normal concrete. High strength and high performance concrete in the compressive zone has been poured out before initial setting of normal concrete in the tensile region. Two concretes began synchronously cement hydration, integrated as an entity after hardening. This confirms the effectiveness and feasibility of the gradient concrete beams. The relative depth of the compression zone of the critical cross section at ultimate limited state is considered as the fundamental variable, flexural experiment of simply supported beams with reinforced gradient concrete was carried out. Based on the distributions of stress and strain of the cross section, the equation and recommended value were proposed for the relative depth of the compression zone of the beam at instantaneous state before cracking. Moreover, the cracking moment equations were introduced by two approaches ： stress and strain analysis of the cross section, and plastic coefficient of tensile concrete. Thus, the calculation methods for average crack spacing, average crack width and maximum crack width were developed for flexural members with reinforcing gradient concrete. It can be served for analysis of the serviceability limit state of reinforcing gradient concrete flexural members.

关 键 词：梯度混凝土 梁 裂缝间距 裂缝宽度 开裂弯矩 

分 类 号：TU375.1[建筑科学—结构工程]