Award of Excellence: Low-Rise Category
Repair and Strengthening of Assumption Convent Lamnarai
Huay Hin, Chai Badal, Lop Buri, Thailand
Submitted by Nontri Co., Ltd.
Assumption Convent Lamnarai
Huay Hin, Chai Badal, Lop Bury, Thailand
Nontri Co., Ltd.
Praves Bangkok, Thailand
Thai Master Builders Co., Ltd.
The Assumption Convent Lamnarai was a three-story, U-shaped reinforced concrete school building, constructed in 1997. It was donated by a real estate company to be used as a school, for elementary and secondary levels. The building appeared to be in good condition, but when the school wanted to add a fourth story on to the existing building, as-built drawings were checked in detail. It was discovered that more than seventy beams, each over 7 meters long, could not support the proposed new load. Thus, a plan was implemented to strengthen these beams with carbon fiber composites, so they could safely support the increased load.
After the surface of these members was removed in the process of surface preparation, cavities inside the beams, along with many cracks, were revealed. When the strength of the concrete was tested by means of the Ultrasonic Pulse velocity Method and by coring out concrete samples for laboratory testing, it was discovered that much of the concrete had low compressive strength and could be considered unsafe.
Before strengthening of the structure with the carbon fiber composites, but after the defective parts of the structure were repaired, load testing was carried out. Results obtained from these tests indicated that structural behaviors under the applied loads could be taken as acceptable. Thus, the structure was then strengthened with the carbon fiber composites, with some modifications to the original repair design due to results from the load tests. After the structure was strengthened, load tests were again carried out, which indicated that the structure was successfully carrying the new load.