【作者】 李天成；

【导师】 易伟建； 陈火炎；

【作者基本信息】 湖南大学 ， 建筑与土木工程， 2008， 硕士

【摘要】 预应力混凝土是以预拉的高强钢筋的弹性回缩力对混凝土结构施加一个预设的应力,使混凝土在荷载作用下以最适合的应力状态工作。预应力能改善混凝土构件的受力性能,带来良好的经济和社会效益,值得深入研究。随着预应力结构研究不断深入,无粘结预应力楼板的特性和理论逐渐完善,设计方法也逐渐成熟,无粘结预应力混凝土结构在高层建筑或大跨度的楼板结构中应用得越来越多。无粘结预应力混凝土楼板技术经济性能(如可靠性、适用性、耐久性、经济性)如何,受什么因素影响,影响程度如何,则需要从楼板设计、施工、使用性能方面进行详细分析。本文对无粘结预应力混凝土楼盖技术经济分析的主要内容如下:1、楼板跨度、荷载等级、预应力Np取值是影响预应力混凝土结构设计的三个主要因素。本文选择一个4×3跨楼板作为计算单元,调整跨度、荷载等级及预应力Np取值,计算出在不同情况下楼板的厚度、配筋等,然后从混凝土消耗量、普通钢筋消耗量、单位面积工程造价方面着手,分析三个因素对无粘结预应力无梁楼盖的经济性能影响。2、人材机市场价格受供求关系的影响上下波动,预应力混凝土楼板的经济性能也随之变化,本文利用敏感性分析了混凝土、普通钢筋和预应力钢筋的价格变动对预应力混凝土楼板的影响程度进行了分析。3、楼盖结构体系有多种,对楼板结构形式的选择必须要有参考指标。本文提出楼板方案综合评价体系。综合评价体系设计遵循SMART准则,它包括特定的、可测量的、可得到的、相关的、可跟踪的五个含义。在楼板综合评价体系中,首先分析了不同评价主体(业主、设计方、施工方)对指标体系构建的影响,然后从楼板技术经济自身特点出发,分析了结构方面指标、使用方面指标、社会经济方面指标、施工方面指标以及风险指标。指标的权重采用层次分析法进行确定,通过建立层次结构模型、构造判断矩阵、计算出各指标的权数并作一致性检验。4、本文结合一个工程实例分析预应力无梁楼板的技术经济性能。采用普通混凝土无梁楼盖和无粘结预应力混凝土楼盖两种结构方案进行设计,并利用综合评价体系对它们的技术经济性能进行对比分析。更多还原

【Abstract】 Prestressed reinforced concrete is based on the elastic recoil force of the pretighten high-strength steel, and then the concrete is imposed by a prestress, so the concrete can work in the most appropriate stress condition. Because the prestress can improve the mechanic performance of the concrete members and bring fine economic and social benefits, it is worth the advanced study. With the constantly development of the research of the prestressed structures, the properties and the theory of unbonded prestressed floor are improved, the same as the design methods are mature gradually. Along with the socio-economic development, the unbonded prestressed reinforced concrete structure is more and more widely used in the high-rise buildings and the large-span floor slab structures. In order to find out the techno-economic performance of the unbonded prestressed reinforced concrete floor, and what factors influence it, and the degree that they influence it, it needs to consider the design, the construction and the usability carefully. The techno-economic analysis of the unbonded prestressed reinforced concrete flat slab floor is made in this paper, the main works are as follows:1. The three important factors are slab span, load level, prestress value Np. In this paper, a 4×3 floor is chosen as the calculate unit. By adjusting the span, the load level and the prestress value Np, the thickness of the floor and the area of the bars are calculated. From the consumption of the concrete, the steel and the cost per unit area, the impact of the three factors on the unbonded prestressed reinforced concrete flat slab floor is analyzed.2. The market price of labor, material and machine is fluctuating with the relationship of the supply and demand, and it has a direct impact on the economic performance of unbonded prestressed floor. It is analyzed by the sensitive method that the influence of the price fluctuations of the concrete, the ordinary steel and the prestressed steel on the unbonded prestressed reinforced concrete floor.3. There are many forms of the floor structure, so that there must be a reference for choice. In this paper, the comprehensive evaluation system is put forward. The design of comprehensive evaluation system is following SMART guidelines, which includes specific, measurable, attainable, relevant and traceable. In the evaluation system of the floor, the impact of the different assessment of the principal (the owner, the designer, the construction side) on the indicator system building is analyzed at first; and then it is analyzed on the basis of the floor’s own techno-economic properties that the indicators of the structure, the usage, the social economy, the construction as well as the risk. The weight of each indicator is determined using the analytic hierarchy process (AHP). Through the establishment of the hierarchy structure model and the judging matrix, the weights can be calculated and the consistency check should be made.4. The paper presents an analysis of the techno-economic performance of the unbonded prestressed reinforced concrete flat slab floor with an actual project. Two forms of structures are designed. One is the ordinary reinforced concrete flat slab floor and the other is the unbonded prestressed reinforced concrete flat slab floor. Their techno-economic performances are compared using the comprehensive evaluation system.更多还原