夹片式锚具锚垫板系列的尺寸估算——预应力锚固区安全探讨之四

锚垫板和螺旋筋是预应力锚固区的重要预埋件,他们和结构混凝土共同工作,承担锚具传来的巨大集中荷载。市售和工程正式采用的锚垫板及螺旋筋,都应符合认可标准试验。预应力结构物的锚固区,可能只有一个锚具,也可能有分布多样的多个锚具。这个区域的混凝土及锚垫板应力复杂多变,结构设计规范很难提供用之皆准的计算准则。预应力技术发祥于西欧,这里的权威们制订了技术认可标准,产品生产者及结构设计者都严格遵从。锚垫板及螺旋筋的产品设计,不可能完全脱离计算,至少估算是需要的。有限元分析法能探讨锚垫板的应力分布状况,有助于拟订锚垫板的设计。该文依据发布在《预应力技术》2012年第3期上的"预应力锚固区安全探讨之三",拟订了圆形夹片式锚具下配用的锚垫板及螺旋筋系列尺寸,可供产品生产者设计产品之用,也可供工程设计、施工单位参考。该文的估算办法参考了美国PTI标准用于普通钢板加工型锚垫板的计算准则,只用了简单的结构力学和经验参数。该文仅拟订了ф15钢绞线1～37孔锚具的锚下配件。实践经验对预应力技术很重要,该文列出了法国Freyssinet体系、瑞士VSL体系、中国QM、OVM、QVM体系的锚垫板、螺旋筋、波纹管尺寸,可供对照参考。该文考虑了我国铁道部门的相关要求。

Dimension estimation of anchor plate series of clip anchors -- Discussion on safety in prestressed anchorage area IV

Anchor plate and spiral reinforcement are important embedment parts in prestressed anchorage area, they work together with structural concrete to bear the huge concentrated load from the anchor. Commercial and engineering official use of anchor plate and screw bar, should meet the approved standard test. The anchoring area of prestressed structures may have only one anchorage device, or there may be multiple anchorage devices distributed in various ways. The stress of concrete and anchor plate in this area is complex and varied, and it is difficult to provide a consistent calculation criterion in the structural design code. Prestressing technology originated in Western Europe, where the authorities have formulated technical approval standards, product producers and structural designers are strictly followed. The product design of anchor plate and screw bar cannot be completely separated from calculation, at least estimation is required. The finite element analysis method can discuss the stress distribution of anchor plate, which is helpful to draw up the design of anchor plate. Based on "Discussion on Safety of Prestressed anchoring Area Part III" published in "Prestressed Technology" No. 3, 2012, this paper draws up a series of dimensions of anchor cushion plate and spiral reinforcement under circular clip anchors, which can be used by product manufacturers for product design, and can also be used as a reference for engineering design and construction units. The estimation method in this paper refers to the calculation criteria of PTI standard used for ordinary steel plate processing anchor plate, and only uses simple structural mechanics and empirical parameters. In this paper, only the anchor fittings of the 1 ~ 37 hole anchorage of Phi 15 steel strand are formulated. Practical experience is very important for prestressing technology. This paper lists the dimensions of anchor plate, spiral bar and bellows of French Freyssinet system, Swiss VSL system, Chinese QM, OVM and QVM system for reference. This paper considers the relevant requirements of China''s railway department.