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ThS. Nguyễn Đắc Hưng

ABSTRACT

A discussion on fining measures for quality violation to building structures (pp. 3-5)

A/Prof. Dr. Cao Duy Tien, Dr. Nguyen Hong Ha

To manage the quality or building structures, the Vietnamese Government has issued the Circular N⁰. 209/2004/ND-CP dated on December 16, 2004. Equivalent to this Circular, the People’s Republic or China has also issued the Circular N⁰. 279 on January 30, 2000 signed by the Primer Minister Zhu Rongji (Chu Dung Co in Vietnamese). In this paper, the authors introduce in detail the Chinese Circular to whom it may concern in order to learn the experience on quality management of building structures by the People’s Republic of China to improve our Circular, in terms of: specific regulations on money punishment and administrative punishment applied to individuals, organizations violating the quality of building structures. In addition, the administrative institution, who is responsible for performing these regulations should also be stated in our Circular.

Calculation of soft soil consolidation subjected to filled soil load (pp. 6-7)

Prof.Dr. Duong Hoc Hai

This paper presents the calculation of soft soil consolidation subjected to filled soil load in case the depth of sand drain (sand well) or the depth of band drain does not reach the bottom of the stratum that causes the settlement. This is a valuable applied and research result of the author as a member of the State Acceptance Council on the quality of bridge and roadconstruction.

Deterioration characteristics or the system of river dikes in the Red river delta during the rainy and flood season (pp. 8-11)

Dr. Sc. Tran Manh Lieu

The system of river dikes in the Red river delta in the rainy and food season are usually damaged due to two scenarios: first, due to permeable instability of the embanlmentand the seceond, due to permeable instability of the base under the dike. This paper presents the behaviour, mechanism and stages of development of dike damage process according to the above scenarios and proposes the solution for protecting the dikes against the damage.

Flexural strength of unbonded post-tensioned prestressed concrete beams subjected to concentrated load(pp. 12-17)

A/Prof. Dr. Nguyen Tien Chuong

The feature of unbonded post-tensioned prestressed concrete structures is there is no simultaneous deformation between the unbonded prestressing steel (tendon) and the remaining structure. It makes the study on the behaviour of unbonded prestressing steel when calculating the bearing capacity of the structure become difficult. Therefore, many experimental formulae have been recommended to be applied in the design standards and many shortcomings have been encountered by Designers. In this paper, the author presents a study on flexural strength of unbonded post-tensioned prestressed concrete beams subjected to concentrated load in order to make a contribution to the limiting the above shortcomings in the design standards.

Attentions required to be paid when applying TCXDVN 356:20005: Concrete and reinforced concrete - Design standard (pp. 18-23)

Dr. Nguyen Vo Thong

In this paper, the auhor presents the new contents of the TCXDVN 356:20005: concrete and reinforced concrete - Design standard that shoud be paid attention to when applying. The contents required to be paid attention to are: the scope of application, new regulations relating to concrete and reinforcing steel, the structural analysis, and so on..

Studying on the influence of triethanolamine and lime stone powder on the development of concrete strength and the formation of Portland cement stone structure (pp. 24-31)

Dr. Nguyen Nhu Quy

The presence of finely ground limestone powder in concrete becomes more and more popular due to its ability to upgrade several properties of concrete. When the limestone powder is used in concrete in combination with triethanolamine (TEA) as an accelerator the hydration and hardening process of Portland cement is likely changed. This study reported the results of the authors’ research on the effect of TEA and limestone powder on strength development of concrete with varying water-cement ratio using statistic design of experiments. The results of SEM and X-ray examination reveal that TEA has a rather profound influence on the concrete strength development as well as the formation of hardened Portland cement paste structure.

Some modifications ofTCXDVN 239:2006 compared toTCXD 239:2000 (pp. 32-33)

Dr. Nguyen Duc Thang

In 2000, Ministry of Construction issued TCXD 239:2000 "Heavy concrete. Guide to assessment of concrete strength in existing structures:" This standard has made a significant contribution to the improvement of concrete quality control. However, the systematism of the standard is not reached, some terminologies are not consistent and some formulae are not correct. Therefore, this standard has been reviewed and replaced with TCXDVN 239: 2006. In this paper,the author introduces the difference between TCXD 239:2000 and its latest version, TCXDVN 239: 2006.

Design, production and utilization of steel frame for load test up to 50,000kN(pp. 34-38)

Dr. NguyenXuan Chinh, Dr. Le Minh Long.

Load test steel frame is a welded space steel plate structure utilized for big load test. In the recent years, the requirement on testing of bridge bearings subjected to big loads is increasing and this has been performed in foreign countries. In this paper, the authors present the calculation, design and production of a Load test steel frame at IBST that can be used for load test up to 50,000kN. The said load test steel frame has been applied sucessfully to the load test of the roof’s beam bearing of the main building – the National Convention Centre (20,000kN), the bearing of Rach Mieu bridge in the national road N⁰. 60 (25,000kN) accroding to technical requirements in the test procedure stated by the Designer.

The subsidence of an elastic uniform rod-like structure with variable cross-section into the soil (pp. 39-45)

MEng. Nguyen Dac Hung

Up to now, the problem of subsidence of an elastic uniform rod-like structure with variable cross-section into the soil, which is subjected to compulsory force induced by two vibrators and to lateral and tip resistance force,has not been solved. In this study, the author has solved the problem by finding out the geometric solution of the problem and by determining the displacement function at the middle cross-section of each part or at the middle cross-section of the whole structure corresponding to each interval or the whole time of subsiding.

The result of this study cannot only be the theoretical basic for solving the problem of subsiding an elastic uniform rod-like structure with variable cross-section into the soil, but also applicable to solving the problem of pulling out of structure with a vibration method.