乾縮潛變對預力混凝土橋樑之影響

Abstract

近年來節塊式的預力混凝土橋樑在國內各項公路橋樑大量被採用，由於其採用的是階段性分段構築，對乾縮潛變的敏感度相當高。一旦在設計過程沒有加以精確估算納入考量，很可能會對橋樑的安全性及耐久性造成很大的影響。國內已有數座橋樑因為乾縮潛變衍生出的問題而需大規模整修甚至拆除重建，足見我們無法去忽視乾縮潛變對預力混凝土橋樑的影響。 本研究從混凝土的乾縮潛變機制出發，進而探究和乾縮潛變相關的理論與預測模式，以及橋樑實務中所面臨到的乾縮潛變問題與解決方法。其中特別針對階段性施工橋樑特別需加以注意的齡期效應加以探討。有心深入瞭解乾縮潛變問題的朋友本文應可做一參考。

In recent years, a lot of segmental prestressed concrete bridges were constructed on Taiwan's highway. Because they were built in many segments in different time, they all have high sensibility to creep and shrinkage. If one does not consider the problem carefully, it may have bad influence on the safety and durability of the bridge. In fact, there have already several bridges must be repaired or torn down because of creep and shrinkage. So the effect of creep can't be ignored on the prestressed concrete bridges. In this research, the basic models of creep and shrinkage are studied. An example is made to investigate these models. And the effects to these prestressed concrete bridges are discussed.