钢管混凝土哑铃形拱肋灌注混凝土时的截面应力分析

针对钢管混凝土哑铃形拱肋灌注混凝土时容易发生爆管事故的问题,建立了有限元模型,对灌注管内混凝土时钢管拱肋的截面应力进行了分析。分析时考虑了各种灌注顺序和工况。分析结果表明:哑铃形截面在灌注腹腔混凝土时,钢管与腹板交接处将产生很大的应力,是产生爆管事故的主要原因。哑铃形截面灌注混凝土时的受力情况与灌注顺序有关,灌注的顺序以先腹腔后两管的顺序最为不利,先两管后腹腔的受力较为有利。为防止爆管事故,建议采用拉杆或型钢加劲腹板,并采用分腔灌注。

Analysis on stresses of dumbbell-shaped cross-section of CFST arch rib during concrete pouring construction

During the construction procedure,filling concrete into the web spaces of concrete filled steel tubular (CFST) dumbbell arch ribs, sometimes cracks will occur in the weld sealing. In this paper, finite element models are established to analyze the stresses of CFST dumbbell-shaped cross-section of arch rib caused by the pressure of fresh concrete. Different construction order and cases are considered. Calculation results show that the great stresses which will take place in the connection points of the steel webs and the steel tubes under the fresh concrete pressure are the main cause of the cracking accidents in construction. The filling order of the concrete to the three spaces (two tubes and one web space) will influence the stresses in the cross-sections. The stresses will be the smallest one in this order that the two tubes are filled with concrete at first and then the web space. The stresses will be the largest one in the order that the web space is filled with concrete at the first. In order to prevent the cracking accident, means should be taken in construction to control the fresh concrete pressure as small as possible, such as, the web space of the rib is divided into several spaces, concrete filled by manpower and steel bars is used to connect the two web places.