KS. Trần Ngọc Đông

Phân tích đánh giá kết quả quan trắc độ lún công trình

ABSTRACT

Computation of blast wave load on structures embedded in the saturated soil medium according to the non-linear visco-elastic model (pp. 3-7)

Prof. Dr. Sc. Nguyen Van Hoi, MEng. Nguyen Duy Tuy, Dr. Nguyen quang trung

The paper presents results on the computation of the load acting on the structures embedded in the saturated soil medium with consideration of displacement and deformation of the structures in the due time, source of the load is a blasting in the air induced dynamic load on the ground surface. Soil media can be homogeneous or layered with deformation characteristics as a nonlinear visco-elastic material within each layer. The problem was solved using one dimensional model. Equations system, solution algorithm and the associate program were built, which allow computing the load on the structures according to the selected model. Based on the results obtained by numerical study, discussion and notes are made regarding to the qualitative and the quantitative effects of the nonlinearity, viscosity and saturation degree on the load acting on the structures.

The sensitivity of reliability and its application to the choice of reasonable design solution (pp. 8-13)

MEng. nguyen trong ha

In this paper, the author presents the sensitivity of reliability and its application to the choice of reasonable design solution in which the reliability is response functional.

The author has set up the problem, proposed some methods for solving the problem and applies the obtained results to a simple example.

Application of SDOF model to seismic base sliding analysis of concrete gravity dams subjected to earthquake loads (pp. 14-18)

MEng. Trinh Quoc Cong, Prof. Dr. Zhang LiaoJun, MEng. Gong Cunyan

Failures of dams may rarely be taken place but in most cases, these would possibly be extremely high consequence events. Some researches on experimental model conducted in the past have indicated that downstream sliding may be the main instability that could be expected during an earthquake. In this study, numerical model is developed to evaluate the dynamic sliding of dams. The method is based on the simplifying assumption that the dam and foundation are rigid. Therefore dam-foundation system can be considered as the Single Degree of Freedom system (SDOF). The result of this model is close agreement with the result taken from experimental model conducted by Mir and Taylor (1996).

Vacuum preloading with vertical drains - theory and recent development – application (pp. 19-28)

MEng. Vu Manh Quynh, Prof. Dr. Wang Bao Tian

Consolidation of compressible soils by vacuum is not a new idea, but only recently has it been successfully applied to extremely soft soils and on large scale projects. The purpose of this paper is to present a brief overview on mechanism, techniques, current theory and practical aspects of vacuum preloading with vertical drains, when applied to soils. The technological matters which control the effectiveness of vacuum preloading are discussed. Also discussed are details which should be considered during the design of field installation. Some recent developments in the vacuum preloading techniques, including the use of new materials, the expansion of the method are briefly summarized.

Influence of agents and humidity on anode characteristics of sprayed zinc layer on concrete (pp. 29-33)

MEng. Bui Thi Thanh Huyen, Dr. Hoang Thi Bich Thuy, Dr. Le Thu Quy

Characteristics of the sprayed zinc layer anode on concrete with different compositions were studied in different submersion conditions. Open circuit potential, working potential, self dissolution rate of the anodes was measured during testing period. After the tests, the compositions of dissolution products were analyzed byX ray diffractometer spectroscopes. It is indicated that the coating anodes can be used with the concrete containing inhibitors or agents. The humidity greatly affects the anode behavior: the higher humidity in concrete, the more negative potentials and the more self dissolution rate are seen. For high humidity e.g. cyclically submerged condition, the concrete additives decrease self dissolution rate of the zinc layer, but have insignificant affect on its open circuit potential and working potential. When humidity is low, the specimen with inhibitor has more positive potential than the specimen with agent, and dissolves at approximately the same rate in both cases. The dissolution products compositions on anode’s outer surface depend much on submersion conditions, but not additives.

Studying measures for reducing segregation of self-leveling keramzit concrete mixture (pp. 34-39)

Eng. Nguyen Duy Hieu, Dr. Tran Ba Viet, Prof. Dr.Sc. Phung Van Lu
With regard to porous aggregate concretes in general and self-leveling keramzit concrete in particular, limiting segregation is the key factor that determine the workability and quality of concrete product. In this paper, the authors present a study for finding out measures to reduce the segregation of self-leveling keramzit concrete mixture, such as: optimizing concrete mixture proportioning problem, using pre-hydrated aggregates, using super-slender steel fibers as reinforcement and using visco-denatured admixture in cement paste.

Green and sustainable materials – a trend of construction development (pp. 40-44)

Dr. Dao Van Dong

The paper presents a trend in research and application of novel generations of construction materials that aimed to “green” and sustainable. Materials keep a main part of expenditure in construction. Energy required to manufacture materials is significantly. Also, quality of materials effects importantly on quality as well as service-life of the constructions. Consequently, research and the use of materials that met low input energy consumption, low wastes generated, high performance and long-term service-life are preferable for the next years to develop sustainable construction in Vietnam.

Analysis and evaluation of buildings’ settlement monitoring results (pp. 45-50)

Eng. Tran Ngoc Dong

In this paper, the author presents the contents relating to the analysis and evaluation of buildings’ settlement monitoring results in order to have a general and visual consideration on settlement of buildings. The contents presented are: evaluation of reliability of settlement monitoring results, expressing settlement of buildings via graphic software and forecasting settlement of buildings according to monitored results.