There are rebuilding and remodeling (with vertical extension) for measures of wornout apartment houses. Rebuilding is the reason for construction wastes produced in large quantities, serious environmental pollutants and soaring price of real estate, so remodeling (vertical extension) business has become an issue. Government made the improvement method of the apartment houses remodeling system which is contained increasing range of permission for vertical extension, securing method of safety, process supplementation to solve civic crowding and temporary concentration.
We must pay attention about something of remodeling (vertical extension). Firstly, it is necessary to reinforce for footings/piles and upper walls that are increased in vertical loads and earthquake loads in proportion to the increasing loads. Reasons of increasing loads come from the increasing number of floors and additional floor area per residential unit. Securing safety is possible whether enactment of lightening loads or not. There are earthquake loads to bear in case of low vertical loads. Aseismatic design for buildings was put in force firstly in 1988 as a design method of permitted strength. The time to add design method of ultimate strength to the related legislation was in 1992. Therefore, securing aseismatic performance according to the present criteria of architectural structure is not easy on the apartment houses in new city. It is necessary to add additional supplement unto the understructure and the upper structure when the vertical extension is executed and structural engineer’s checking is essential.
The most of these objects for remodeling (vertical extension) in the apartment houses are the buildings dated over 20~30 years old. The measures for securing building’s safety could be made. For example, they should check whether they would be weakened on the reinforced steel bar and concrete strength between the passing time with surrounding influence and the initial moment of design and whether they would be declined of durability by means of concrete carbonatization. Safety checking to see the performance of existing structures must be made as the first and the second test between the time of before and after moving. Especially, defects of the buildings could not be checked because of finishing materials, so the second safety checking is important for whole members of structure. Because it is estimated to increase in the demand of vertical extension, securing safety would be the important thing. Checking of structural safety should be made by structure profession engineers in special organization and external experts at the time of reinforcement of safety checking and architectural design evaluation and approving of business plan. And also, construction inspector during the construction period must get the checking of architectural structure profession engineer about the change of design which is making influence to structures of the buildings. Securing safety for vertical extension is very important thing to protect human life and to prevent the damage of property. Sufficient checking and the reasonal measures of the specialists should be suggested. For this, the criteria on the vertical extension structure from The Institute of Construction Technology and the criteria from the checking (field investigation) of Korea Corporation of Facility and Safety are to be made eagerly by the specialists.