预应力混凝土梁上拱度及其影响因素

Deflection upward of pre-stressed concrete beam and its influencing factors

预应力混凝土结构以其独特的优越性，在近数十年来得到了迅猛发展。但由于混凝土的收缩徐变引起的过度起拱，不仅影响了结构的正常使用．也给施工带来了一些不必要的麻烦。因此，为了避免由预应力及混凝土收缩徐变等因素引起的过度起拱带来的诸多麻烦．迫切需要一种符合工程实际的计算方法较精确地求得顸应力混凝土梁的上拱度。从而采取有效的处理措施加以控制。本文结合工程中的实际问题，探索并分析上拱发生的机理以及相关的影响因素，针对各种施工方法、工艺．以比较简单的理论公式反映上拱度变化的规律，提出一种能准确预估预应力起拱度的计算方法，并通过理论研究成果．提出合理控制上拱度的若干建议。

Prestressed concrete structure, with its unique advantages, has been developing rapidly in recent decades, However, the excessively deflection upward of pre-stressed concrete beam caused by the concrete shrinkage and creep not only affect the normal use of the structure, but also to the construction of some unnecessary trouble. Therefore, in order to avoid the excessively deflection upward caused by the concrete shrinkage and creep,there is an urgent need for a accurately method of how to obtain the deflection upward values of pre-stressed concrete beam so we can take effective measures to control them. In this paper, according to the practical problems in engineering,I had analyzed the mechanism of the deflection upward and its related factors. In view of variety of construction methods and technology, I had found out the deflection upward changes in the law by relatively simple theoretical formula ,and proposed a calculation method which can accurately estimate the degree of deflection upward.At the final ,according to the results of theoretical studies,Iput forward a number of reasonable recommendations to control the deflection upward of pre- stressed concrete beam.