Risks and Cost Escalation of Underground Construction Package of High-rise Building

In the construction process, the underground construction package takes a big ratio of project cost. Underground construction package faces a lot of invisible factors which can affect the project cost a lot such as underground water level, existing neighbor projects, soil conditions, underground obstructions, etc. Furthermore, deep excavation of underground construction is also very important. The unreasonable method can affect the project cost such as: method of excavation, soil disposal, shoring system etc.

In recent years, the urbanization in Vietnam develops so fast, which leads to the requirement of basements for almost high-rise buildings as well as for underground parking, subways, tunnels, etc.

In fact, there are no solutions appropriate enough for underground construction. Moreover, it must be recognizable that excavation methods are applied differently in various locations. Some of the construction technologies can depend on the characteristics as follows:

- Geotechnical conditions

- Relief conditions

- Available equipment

- Construction and design experience

- Neighborhood construction

- Drainage conditions

- Waterproof methods and methods of reducing water flow

- Impacts on underground water level

- Load

- Environment

- Expenditures

- Duration

- Risks

Design consultancy and project management play an important role in the success of the project. Construction consultants are responsible for designing and selecting experienced contractors, controlling risks which may badly affect investors and the community.

Mr. Bien Nam Hai made a case study aimed to:

1. study cost estimation in a construction project in Vietnam as a case study.

2. study cost risks and escalation.

3. discuss strengths and weakness of the cost estimation, control and risk management of the case study.

Conclusion

Methods of basement design and methods of basement construction have a close connection, for the design characteristics of the basement protection structure depend on the construction technologies. The basement protection structure is also the one to stand the permanent force. Therefore, the overall construction methods start from basement design. Currently, the construction technologies are so diversified that the design and construction company has to analyze and present the design and construction methods most appropriate to the available conditions.

Economically, the basement construction is the one that may make a big loss without appropriate design and construction methods.

Technologically, the basement construction is complicated because of being performed in such a depth that the construction itself and the associated construction are likely to have problems. Therefore, design, construction and supervision must be paid much attention to.

Recommendations

The arising problems of the basement and underground construction have been the first concerns in Vietnam, especially to construction engineers, owners and managers. Therefore, knowledge enhancement, experience accumulation, technology exchange, human resource and professional improvement play a crucial role. There must be well-qualified human resources first and then well-qualified basements come. High values, low prices and enhanced quality.

The conditions of geography, hydrography, nature and climate in Vietnam are complicated and diversified as well as a lot of weak ground. Vietnam is among the five countries to be greatly affected by the climate changes. Thus, careful study of design, construction, monitoring, management, exploitation and maintenance of the basement construction must be performed professionally and with good career morality. Only professional engineers are able to take charge of signing the drawings, managing, leading and performing the basement construction. Foreign consultancy is also important, but Vietnam must have strategies to develop the human resource for the basement development technology.

Obviously, without achieving such vital requirements, there must be big losses of labor and property from the state and owners. Also, it costs a lot to repair the mistakes of the basement design and construction.

Abstract

This study, which refers to the theories and the standards system, has expressed the concept of cost estimation, cost control, cost risks and escalation of underground construction package of high-rise building

The next part of this report is the case study of Commercial Center, Textile Fabrics, Department Store and Apartment project, study cost estimation and cost escalation of the basement of high-rise building. This is also the objective of this study.