PGS.TS. Cao Duy Tiến, TS. Vũ Thị Ngọc Vân: Viện KHCN Xây dựng-một số công nghệ chuyển giao áp dụng hiệu quả trong thực tế 2 năm 2005 ¸ 2006

GS.TS. Nguyễn Văn Phó, TS. Nguyễn Đình Xân: Biện pháp công trình và phi công trình trong phòng ngừa và giảm nhẹ thiên tai

KS. Uông Hồng Sơn, ThS. Lê Văn Minh: Xác định nguyên nhân và đề xuất giải pháp hạn chế nứt ống bê tông dự ứng lực D 2400mm

ThS. Hoàng Quang Nhu: Phương pháp tính tổn hao ứng suất trước do từ biến và co ngót của bê tông

ThS. Nguyễn Thanh Bình, TS. Trần Bá Việt: Ảnh hưởng của cốt sợi thép phân tán đến tính chất của bê tông mác cao trong điều kiện khí hậu nóng ẩm Việt Nam

TS. Nguyễn Như Quý: Nghiên cứu ảnh hưởng của phụ gia mịn bột đá vôi và tro bay nhiệt điện đến tính chất của hỗn hợp bê tông bơm

ThS. Nguyễn Nam Thắng, TS. Phạm Văn Khoan, TS. Lê Quang Hùng: Tác dụng ức chế ăn mòn cốt thép của canxi nitrit tại khe nứt bê tông

ThS. Nguyễn Văn Tá, TSKH. Trần Mạnh Liểu, ThS. Cao Thanh Tùng: Phương pháp dự báo khả năng sạt lở bờ sông theo chỉ tiêu tích hợp các yếu tố điều kiện kỹ thuật – tự nhiên vùng ven sông

ThS. Nguyễn Sơn Lâm: Các vấn đề an toàn môi trường khi xây dựng nhà máy điện nguyên tử (NMĐNT) ở Việt Nam

PGS. TS. Nguyễn Hùng Sơn: Công trình tường chắn đất có cốt trên vùng núi khai thác mỏ

ABSTRACT

Institute for Building Science and Technology - Some technologies transferred and effectively applied in the two years 2005-2006 (pp.3-5)

A/Prof. Dr. cao duy tien, Dr. Vu thi ngoc van

This paper presents some technologies transferred and effectively applied in the two years 2005-2006 by the Institute for Building Science and Technology (IBST) in the following fields: Geotechnical engineering, Concrete and Construction chemical products, Restoration and conservation of monuments and cultural structures, Structural engineering and Surveying engineering. By presenting technologies transferred and effectively applied in the two years 2005-2006 the authors of the paper would like to seek the cooperation by individuals, organizations that are interested in the building science and technology field.

Structural and non-structural measures for prevention against and mitigation of damage caused by natural disasters (pp. 6-9)

Prof. Dr. nguyen Van pho, Dr. nguyen dinh xan

This paper presents the authors’ opinions on the principles for structural and non-structural measures for prevention against and mitigation of damage caused by natural disasters, particularly the typhoons. In addition, the authors also present their initial considerations on specific measures that can be applied to the construction of building structures in order to overcome the consequences caused by the typhoon Shansane, which landed in the middle area of Vietnam on October 2006.

Determination of the crack’s cause and proposing measures for limiting cracks in prestressed RC pipes with a diameter of D2400mm (pp.10-15)

Eng. Uong Hong Son, MEng. Le Van Minh

This paper presents an analysis by the authors to determine the crack’s cause that happned toprestressed RC pipes with a diameter of D2400mm. Potential causes are analyzed and investigated, such as: concrete quality of the pipe’s core, the transportation and installation, influence by environmental temperature, deformation due to prestress and shrinkage of concrete. In the end, according to the author, the cause of cracks is concrete shrinkage and a measure for limiting cracks in prestressed RC pipes with a diameter of D2400mm wasproposed.

Estimating prestress loss of prestressed concrete structures due to creep and shrinkage (pp.16-21)

MEng. hoang quang nhu

The time-dependent losses of concrete creep and shrinkage are all of significant importance in prestressed concrete structures. Effective determination of long-term prestress losess is an integral part of the design of prestressed concrete structures. An over-prediction in prestress loss results in an overly conservative design for service loads, while an under-prediction in prestress losses could result in significant cracking at service loads. A precise determination of stress losses in prestressed concrete members is a complicated problem because the rate of loss due to one factor, such as relaxation of tendons, is continually being altered by changes in stress due to other factors, such as creep of concrete. This procedures here presented will provide more accurate results than by previous methods which gave no consideration to the actual shrinkage and creep coefficient.

Influence or discared steel fibers on the properties of high-grade concrete in the hot-humid climate of Vietnam (pp.22-29)

MEng.Nguyen thanh Binh, Dr. tran Ba viet

There have been many studies on steel fiber reinforced concrete in Vietnam and all over the world. However, though the study on discared fiber reinforced concrete has been interested in, this study has not become systematical.

In this paper, the authors present a study on the influence of discared steel fibers on the properties of high-grade concretes in the hot-humid climate condition of Vietnam such as: plastic shrinkage, anti-cracking due to plastic shrinkage, the development of concrete strength with the time, drying shrinkage,.. of steel fiber reinforced concrete, by comparing these properties with that of non-fiber reinforced concrete with the same grades.

Some studies into the effect of fine filler ground limestone and fly ash on properties of pump concrete mix (pp.30-33)

Dr. Nguyen nhu quy

Compared to concrete mix transported without using pump, the pumping concrete mix must have suitable slump and a mortar content within specified range. In additions the pumping concrete mix is characterized by good slump retention capacity. In this report the authors used ground limestone powder and fly ash as fine filler in combination with high range water reducing admixture to upgrade some properties of pumping concrete. Some conclusions have made on the capacity of used type of finefiller in reducing slump loss of pumping concrete mix with time.

Some research results on the effectiveness of calcium nitrite corrosion inhibitor in cracked concrete structures (pp.34-37)

MEng.Nguyen Nam Thang, Dr.Pham Van Khoan, Dr.Le Quang Hung

This paper presents some research results on the effectiveness of calcium nitrite corrosion inhibitor (CN) in cracked concrete. Based on the results obtained, the authorsfound that calcium nitrite can protect reinforcement in cracked concrete regions from corrosion over a test period of 24 months. To study, the test specimens (with a concrete cover of63mm) and a crack width less than0.5mm were exposed to alternating salt-solution and experienced a continuous drying process.

Method of evaluation and prediction of riverside erosive ability according to intergrative target of factors of technological – natural condition in riverside area (pp.38-41)

MEng. Nguyen Van Ta, Dr. Sc.tran manh lieu, MEng. Cao Thanh Tung

Based on analysis of cause, condition and mechanism of riverside erosion, some factors of technological – natural condition are chosen as: unhomogeneityt of geological structure (Eđc),material composition (Cd),carve durability (C), terrain segment high (DH), riverside dip angle (tga;), underground water level fluctuation (Dh), yearly crest of a flood (H), direction of current effect on riverside (y).

This paper introduces method of density quantitative evaluation of each factor above-mentioned and integrate them into quantitative target for evaluation of riverside erosive ability. The method was used for evaluating the Red riverside erosive ability in Hanoi area.

The environmental safety matter when constructing Nuclear power plants in Vietnam (pp.42-48)

MEng. nguyen son lam

Nuclear power plants have a superiority over other kinds of power plants such as: high ouput, occupied land is less than the ussually required,.. However, there is an inherent problem with Nuclear power plants: the treatment of discharged wastes and radioactive leakage. The problem might cause serious environmental impacts.

This paper presents the required of aspects of environmental safety matter that should be observed when constructing and operating Nuclear power plants in Vietnam including: environmental aspects, environmental impact assessment caused by Nuclear power plants and some environmental strategies and specific measures for ensuring the environmental safety.

Reinforced retaining wall in areas of mining subsidence (pp.49-53)

Prof. Dr. Nguyen hung son

In this paper, the author presents some research results on reinforced retaining wall in areas of mining subsidence. With the help of Plaxis software, the author has simulated the forced deformation of the ground as a gradual subsidence below the construction during the exploitation process. The calculation showed the inclination of wall’s surface inrelation to horizontal ground strain. In addition, variations of extreme axial force in layers of reinforcement during calculation are also presented in the paper.