Reinforced concrete slab structural reinforce-ment of discussion

• Main Authors: Liu,Chen-Chung, 劉承宗
• Other Authors: Shiau,Yan-Chyuan
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/87197631305600275813

碩士 === 中華大學 === 營建管理學系 === 104 === Geologically, Taiwan is located in an island-type climate area where the summer is hot and humid and it is regularly hit by typhoons and earthquakes. During the winter, Taiwan is subjected to strong northeast bound monsoon winds. As Taiwan is surrounded by the sea, the air usually carries salty chloride ion, moisture, oxygen and chloride ion that it tends to cause erosion through structural cracks. This results in the oxidizing corrosion of steel as well as the cracking and peeling of concrete structure. In the early days, the steel bars in RC structure were vulnerable to structural bursting damage. Usually, the cement paste or mortar was used for repairs. Recently, epoxy mortar, or light-mass hollow mortar, has been developed and used in the patch-up applications and it will achieve certain degree of structure repairing effect initially. However, the rusty por-tion deep of the steel bars deep inside the structure cannot be effectively removed and it tends to cause continuous oxidization in the steel bars. As a result, the RC structure will become oxidized from the deeper layer of steel bars and once again lead to volumetric swelling, cracking, and peeling. Furthermore, the repairing layer or the patch-up on the surface will peel off, thus losing the original repairing function and purpose. To prevent the reoccurrence of oxidization or the stress-concentrating phenomenon on the patch-up surface as to cause ineffective repairing result, in addition to thoroughly re-move the rust from the oxidized steel surface, the subbase should be coated with high-penetrating epoxy in order that the poor-quality concrete and oxidized rusty steel bars should be fully soaked to produce the binding layer and repairing link in tiny cracks. In the meantime, the CFRP patch-up material will be used for the beams and slabs. Furthermore, the stressed reinforcing material should be used for both ends, with splicing and overlap-ping method applied at the beams and slab. The corner should be secured at small spacing with L-shape steel and chemical anchoring bolts. The gap between L-shape steel and slab/beams should be filled with epoxy mortar. The shorter side of the slab should be rein-forced with mini H-shape steel (125*125) for every meter. The CFRP should be anchored and reinforced for jointing with L-shape and mini H-shape steels. By coordinating with 8% of volumetric swelling properties from chemical reaction for the epoxy patch-up material, a tight and perfect clamping force will be developed for CFRP and steel members. According to the construction method of this research, the result indicated that it can change the conventional patching method where the steel oxidization phenomenon reoccurs several years after. Such method has been implemented in the community complex and in-dividual house projects in high-humidity area such as Linkou, Tamsui, and Neihu areas as well as the mountainous location in Xindian area and these buildings still maintain their original status after being erected for 7 to 8 years until now. Currently, the visual and tap-bouncing methods are executed for the monitoring and there is not any internal swell-ing or peeling sign. Besides, it also saves the construction cost and minimizes the subse-quent maintenance problem. With correct patch-up method, it can really extend the lifespan of the structure.