I want to share this incident that happened in my Job site. Just let me describe how's this building. This building is called Villa B5, and same kind of units have 5 in this job site. Because of the design level, Unit 1 and 5 was built 4.5 meters higher than the others. Despite, beam & slab of Villa B5 was supported by 4 meter height of stumps. Therefore, tie beam was provided to prevent the buckling effect of stumps, somemore to provide a further support to the wall beside.

 

However, due to some unwanted accident and manners (rain, backfilling, water drainage etc), a column stump at swimming pool location was out of position to 200mm. Opppsssss, something wrong with this column already. It was damaged? or it just setting up problem? After some discussion, we started to excavate this column to expose the truth.

 

Once we excavated down, some obvious crack lines have been attracting our attention until the tie beam was exposed. The tie beam was totally rotated, and have made the stumps beside shear off. Yeah! this considered as structural failure. The stump was found a serious crack at its bottom, and already sheared off.

 

Beside it, the tie beam that tying the wall was totally damaged and performed as V shape. Its steel bars was broken but no crushing of concrete was found.

 

These tie beam was designed in 250X400, and reinforced as 4T13 and T10 in 200mm spacing center to center. From this incident, we can see that this tie beam was not designed to its ultimate limit state, as rebars broken but concrete still remain good.

 

Since this happened, the damaged members was removed (hacked, or cut it) and redo again.