Tạp chí Khoa học Công nghệ Xây dựng số 3+4/2013
Ngày tạo : 02/07/2015
Tạp chí Khoa học Công nghệ Xây dựng số 3+4/2013
TS. Nguyễn Hồng Hà, ThS. Nguyễn Hồng Hải, ThS. Vũ Xuân Thương
Phương pháp thiết kế kháng chấn dựa theo tính năng cho nhà cao tầng, download
ThS. Phạm Nhân Hòa, PGS.TS. Chu Quốc Thắng, KS. Hồ Viết Tiên Phước
Điều khiển dao động hai kết cấu liền kề được trang bị hệ cản chất lỏng nhớt và hệ cản ma sát, download
KS. Nguyễn Chí Hiếu
Tổn hao ứng suất trong thiết kế sàn bê tông cốt thép ứng lực trước căng sau, download
TS. Nguyễn Minh Tâm, KS. Phạm Quang Tạ, ThS. Võ Minh Thiện
Phân tích sức chịu tải của móng nông đặt trên mái dốc bằng lý thuyết phân tích giới hạn, download
PGS.TSKH Trần Mạnh Liểu, ThS. Nguyễn Quang Huy, KS. Nguyễn Thị Khang, ThS. Hoàng Đình Thiện, CN. Bùi Bảo Trung
Dự báo nguy cơ và cường độ phát triển trượt lở khu vực thị xã Bắc Kạn, download
ThS. Ngọ Văn Toản
Nghiên cứu ảnh hưởng của tro trấu và phụ gia siêu dẻo tới tính chất của hồ, vữa và bê tông, download
TS. Trần Văn Miền, ThS. Nguyễn Lê Thi
Nghiên cứu đặc trưng nhiệt của bê tông sử dụng hàm lượng tro bay lớn, download
TS. Nguyễn Minh Tâm, ThS. Hoàng Bá Linh
Nghiên cứu sử dụng giải pháp Jet Grounting giảm chuyển vị ngang hố đào, download
TS. Lê Đức Tình, PGS.TS. Trần Khánh
Xác định thời gian trễ chuyển dịch so với thời điểm tác động của tác nhân gây chuyển dịch, download
ThS. Lê Văn Hùng, ThS. Nguyễn Xuân Hòa
Kết hợp mô hình trọng trường toàn cầu EGM2008 và đo độ cao GPS thủy chuẩn nhằm nâng cao độ chính xác của kết quả đo cao GPS,download
Abstract
Performance based seismic design for tall buildings
Dr. Nguyen Hong Ha, MEng. Nguyen Hong Hai, MEng. Vu Xuan Thuong
The performance based seismic design is being considered a new trend of seismic-resistant design. The method is becoming a more widely accepted alternative to prescriptive design codes, especially for buildings with complex structures such as super-tall buildings that are beyond application of current standards. This paper presents basic issues of seismic-resistant design method utilizing the performance based seismic design. Some comparisons are also provided showing the advantages and disadvantages of the new approach compared to current design methods.
Passive control of two adjacent buildings with viscous fluid dampers and friction dampers
MEng. Pham Nhan Hoa, A/Pro. Dr. Chu Quoc Thang, Eng. Ho Viet Tien Phuoc
From the advantages and disadvantages of both viscous fluid dampers and friction dampers, this paper presents a new solution of seismic resistance for two adjacent buildings equipped with these dampers to mitigate earthquake-induced motion. This paper therefore proposes the model, the differential motion equation, and two algorithms based on Newmark numerical integration method so as to resolve the equation. Finally, the paper draws conclusions on advantages and disadvantages of application of these types of dampers in a system of two adjacent building structures.
Loss of stress in design post – tensioning prestressed reinforced concrete
Eng. Nguyen Chi Hieu
Loss of stress is an important factor in analysis and calculation of prestressed reinforced concrete structure.Design standards in some countries give methods of calculation of stress losses and results of calculations are different. This paper presents methods and examples of calculation of stress losses according to some of standards being applicable in Viet Nam.
Slope stability of slope using upper bound limit analysis based on CS-FEM and SOCP
Dr. Nguyen Minh Tam, Eng. Pham Quang Ta, MEng. Vo Minh Thien
In this paper, upper bound limit analysis is applied to investigate the bearing capacity of strip footing placed on slope. The soil is modeled by well–known Mohr-Coulomb failure critertion with the associated flow rule. The cell-based smoothed finite element method (CS-FEM) is used to approximate displacement field. By utilising the Mosek program, failure mechanism and bearing capacity of shallow foundation resting on the slope are determined.
Prediction of landslide hazard and development magnitude in Bac Kan town
A/Pro.Dr.Sc. Tran Manh Lieu, MEng. Nguyen Quang Huy, Eng. Nguyen Thi Khang, MEng. Hoang Dinh Thien, BSc. Bui Bao Trung
This paper presents the basis of the method and procedure of application of multi-variable statistical index model in forecasting landslides probability in ArcGIS platform for Bac Kan town, in which landslide hazard forecast map and landslide hazard zonation map are built based on a weighted combination of conditional and cause factor maps: geological lithology, geomorphology, weathering coverage; engineering geology, rainfall, land use, map of lineament density, density of fractures, rock dip azimuth deviation and fracture system 1&2 dip azimuth deviation, DEM, slope, slope aspect, horizontal and vertical segmentation, tectogenesis.
The paper also presents quantitative prediction methods of landslide development magnitude (landslide volume) based on the quantification of the weight of landslide driving factors, establishing equation of regression for calculating the volume of landslide, and landslide volume prediction map. The method was applied to Bac Kan town.
Landslide hazard forecast map, landslide hazard zonation map and landslide volume prediction map is the basis for calculating and establishing human risk forecast map, property risk forecast map caused by landslide in Bac Kan town, also for orientating technical solutions to prevent landslide and sustainable urban development, urban planning.
Researching about the influence of ember rice husk and super glutinous additives to the character of lakes, mortar and concrete
MEng. Ngo Van Toan
In the production of high quality concrete, the problem to be solved is guaranteeing good workability and low ratio water/cement of the mixture, but the cement rate is suitable and using little water. This article reports initial results of the use of super plasticizer additives basing on Naphthalene and rice husk ash to produce concrete with water–cement ratio from 0.3 to 0.45. These effects of additives to the standard workability point and hardening time of mortar were investigated at different quantity of additives. For mortar, the gain of strength in time depending on rice husk ash, the influence of super plasticizer additives and rice husk ash to waterproofing capacity of concrete were studied. The result shows that the combination between super plasticizer and husk ash has improved considerably the quality of mortar and concrete. This is important for the development and application of these additives in the production of high quality concrete.
Investigation on thermal characteristic of concrete using high volume of fly ash
Dr. Tran Van Mien, MEng. Nguyen Le Thi
The phenomenon of cracks due to thermal stress often occurs in mass concrete. Therefore, the hydration heat of cement is concerned seriously in concrete mix design. This paper presents results of investigation on thermal characteristic of the concrete in term of maximum temperature, Tmax, and the temperature difference between concrete and environment. The concrete under investigation had different fly ash content replacing cement. The fly ash content replacing cement PC50, which was used for concrete mix design with grade of 60MPa at 28 days, varied from 20% to 50%. The results showed that the maximum temperature of concrete and the temperature difference between concrete and the environment decreased, also the time of temperature increase was prolonged, as the fly ash content replacing PC50 cement increased. This implied that thermal stress and cracks of the mass concrete is limited as the high volume of fly ash is used in the mass concrete.
The study solution use jet grouting to reduce the horizontal displacement of deep excavation
Dr. Nguyen Minh Tam, MEng. Hoang Ba Linh
Horizontal displacements exceeding the permitted limits and ground subsidence usually caused by deep excavations construction are the main cause of damage to the adjacent buildings. Therefore, it is imperative to minimize the horizontal displacement of the diaphragm wall. Based on the studies abroad, this paper describes the application of jet grouting in order to reduce the horizontal displacement around excavations in Vietnam geological conditions. The soil in the bottom of the excavation area are replaced in part by the jet grouting piles (JGPs) to increase passive resistance. Numerical methods of analysis are used for evaluating the effectiveness of jet grouting.
Determination of time delay shift with the time of the imfact of shifting the causes
Dr. Le Duc Tinh, A/Pro.Dr.Sc. Tran Khanh
The paper presents the determination of time delay shift with the time of the impacts that cause the displacement of the subjects of monitoring. The determination of the time delay not only allows for accurate assessment of the relationship between displacemements and their causes, it also helps the planning the suitable time of monitoring.
Combined global gravity model EGM2008 and GPS leveling height to improve the accuracy of results GPS height
MEng. Le Van Hung, MÈng. Nguyen Xuan Hoa
There is often a difference between geodetic height (H) and standard height (h), called height anomaly. The variation of this value does not follow a rule and depends on the inner physical structure of the Earth. The accuracy of GPS height depends primarily on the precision of interpolation of height value anomalies. Scientists around the world have built some gravity models, model EGM2008 among them, however this model has not yet satisfy the precision demand for GPS height measurement applications in Vietnam. This paper studies the method of combining calculation methods of height anomalies to improve the precision of GPS height measurements.
