Các phương pháp phân tích động phi tuyến kết cấu theo lịch sử thời gian trong SAP 2000 (Phần 1), download
ThS. Trần Ngọc Cường
Thí nghiệm nghiên cứu ứng xử của công trình ngầm dưới tác dụng của động đất, download
ThS. Lê Văn Tuân, GS. Zheng Yong – Lai
Ứng dụng biến đổi Hilbert-Huang để chẩn đoán hư hỏng trong kết cấu dưới của cầu, download
PGS. TS. Bùi Đức Chính
Phân tích Khung phẳng với các tham số đầu vào là đại lượng khoảng bằng mô phỏng MONTE CARLO, download
TS. Đặng Xuân Hùng, ThS. Nguyễn Trọng Hà
Tính dễ xây dựng và nâng cao tính dễ xây dựng trong thiết kế và thi công công trình, download
ThS. Nguyễn Hải Lộc, PGS. TS. Nguyễn Thế Quân
Nghiên cứu quy trình dưỡng hộ nhiệt ẩm cho bê tông đúc sẵn, download
TS. Trần Văn Miền, TS. Nguyễn Đức Thắng, ThS. Nguyễn Lê Thi
Nghiên cứu sử dụng vi khuẩn Bacillus subtilis Hu58 trong vữa Xi - Măng có khả năng tự liền, download
KS. Nguyễn Ngọc Trí Huỳnh, TS. Nguyễn Khánh Sơn
Tính chất cơ học của bê tông geopolymer sử dụng tro bay gia cường sợi poly-propylene, download
TS. Phan Đức Hùng, TS. Lê Anh Tuấn
Nghiên cứu dự báo quan hệ tải trọng - độ lún của cọc từ kết quả nén tĩnh cọc tiết diện thu nhỏ, download
TS. Trịnh Việt Cường, ThS. Đoàn Nguyên Quyền
Một phương pháp đơn giản hóa cho việc tính toán mố cầu chắn nền đắp cao trên móng cọc qua đất yếu, download
ThS. Phạm Anh Tuấn
Về các tiêu chuẩn khảo sát đánh giá và phân loại tình trạng kỹ thuật nhà và công trình xây dựng, download
PGS. TS. Nguyễn Xuân Chính
ABSTRACT
Numerical characteristics of integration methods for nonlinear time-history analyses in SAP2000 (pp.3-14)
MEng. TRAN NGOC CUONG
This paper introduces some integration methods for nonlinear time-history analysis built-in software SAP2000 to help new users get the basic understanding of the characteristics of each method as well as scope of their applicability. For each method, this paper offers basic properties such as: Formulation (explicit or implicit), stability condition (if any), accuracy, relative period error, numerical damping ratio… thus giving scope of applicability proposal. Some examples are given to illustrate and clarify the numerical characteristics of each method.
Shaking table test study on characteristics of underground structure subjected to earthquake (pp.15-24)
MEng. LE VAN TUAN, Prof. ZHENG YONG – LAI
This paper presents the seismic response of underground structure under earthquake using shaking table testing. The testing used a 1/30 structure scaled model, with a cross-section of two-storeys three-spans, using galvanized steel wire and micro-concrete. The input motions include the El Centro ground motion records and the Shanghai wave. The record parameters of the test include: the acceleration responses of model soil and structure and the strain in the structure. Based on the test data, analyze the characteristics of underground structure subjected to an earthquake. The results show that, under the earthquake, the weak possitions in the underground structure are at the top and the bottom of the interior columns. Besides, the seismic response of underground strucuture depends on characteristics of accelerations and the frequency of input ground motions.
Application of Hilbert-Huang transform in diagnosis of damages of bridge substructure (pp.25-31)
A/ Prof, Dr. BUI DUC CHINH
This paper introduces the initial findings on the diagnosis damages of bridge substructure based on Hilbert-Huang transform. , The article includes: The content of the Hilbert transform; the decomposition of a signal into the Intrinsic Mode Functions (IMF‘s) according to the Empirical Mode Decomposition (EMD) method and the Ensemble Empirical Mode Decomposition (EEMD) method; some initial results from application of Marginal Hilbert Spectrum (MHS) in the diagnosis of damages of bridge substructure.
Analysis of plan frame with input interval parameters using Monte Carlo simulation (pp.32-40)
Dr. DANG XUAN HUNG, MEng. NGUYEN TRONG HA
This paper presents a method for the structural analysis with the input parameters being interval variables, in combination with finite element method (FEM) and Monte Carlo simulation (MC). The method is detailed via an example of plan frame analysis with material properties, geometric dimensions, and loads as the interval variables. The results are then compared with existing literature.
Constructability and improving constructability in design and construction of construction works (pp.41-46)
MEng. NGUYEN HAI LOC, A/ Prof, Dr. NGUYEN THE QUAN
Obtaining design alternative which facilitates the construction processes, enhances productivity, assists the project quality and facilitates the maintenance has become the objective of the construction industry and construction projects. Constructability can bring both qualitative and quantitative benefits to each construction project and can have impact on the whole industry. This paper discusses about constructability, articulates the difficulties for this job and presents the approach for implementing the formal constructability review process together with important constructability tools.
Investigation on steam curing procedure for precast concrete (pp.47-53)
Dr. TRAN VAN MIEN, Dr. NGUYEN DUC THANG, MEng. NGUYEN LE THI
Steam curing is curing method by supplying steam at high temperature under ordinary pressure. The large-sized elements, commonly prestressed concrete elements are applying this curing method. The research results in this paper show that, depending on the content of fly ash for cement replacement and the required strength at specified age, the appropriate steam curing procedure can be established.
Studying the use of bBacillus subtilis hu58 to formulate self-healing cement mortar (pp.54-59)
Eng. NGUYEN NGOC TRI HUYNH, Dr. NGUYEN KHANH SON
Literature study reveals that by using some bacteria could help us improving physico-mechanical properties of cement/concrete materials at both early and later age. Based on bio-mineralization process, this biocement receive much attention among material scientist as a sustainable and environmental friendly solution for construction industry. In this experimental campaign, we used a new microorganism named Bacillus subtilis HU58 to formulate bacteria modified cement mortar and investigated the healing effect after one year of curing time. Results showed the role of precipitated calcite to improve both compressive and flexural strength of mortar samples: 60MPa > 56MPa (in compression) and 11MPa > 8.5MPa (in flexion) in compared with control sample. Furthermore these calcite permit 40x40x160mm prismatic sample to heal by itself the artificial crack.
Mechanical properties of poly-propylene fiber reinforced fly ash based geopolymer concrete (pp.60-67)
Dr. PHAN DUC HUNG, Dr. LE ANH TUAN
This paper studies the influence of poly-propylene fibers on the properties of geopolymer concrete. The poly-propylene fibers with content of 0.5% - 1.5% by volume and length to diameter ratio from 100 to 500 were used in this research. Fly ash-based geopolymer concrete was B25 grade. Results showed that poly-propylene fibers reduced the workability of fresh concrete. Fiber content, fiber length and length to diameter ratio strongly affect to the properties of concrete. Mechanical properties of geopolymer concrete reinforced with 0.5% content of poly-propylene fibers were improved most. Experimental results showed that the strain values of geopolymer concrete vary from 0.0022-0.0031, the elastic modulus changes from 21.32 GPa - 26.1GPa and Poisson ratio achieves 0.12 - 0.152.
Forecasting load-settlement relationship of piles from results of load testing of pilot piles (pp.68-75)
Dr. TRINH VIET CUONG, MEng. DOAN NGUYEN QUYEN
The execution of static loading tests of piles of high bearing capacity is potentially unsafe, time consuming and expensive. In some cases, when the required test load are too high or when the site conditions are not favorable, alternative solutions may be applied by conducting tests on model piles of reduced section (pilot piles) for collecting data in order to estimate the bearing capacity of prototype piles that will be used for the project.
This report summarises available research on pilot piles abroad and presents some initial results of assessment of the possibility of using pilot pile tests in investigations for design of pile foundation in Vietnam.
A simplified method for analysis and estimation of full-height bridge abutment on pile foundation through soft soil (pp.76-83)
MEng. PHAM ANH TUAN
The main aim of this paper is to introduce a new and simplified method named SAPA for analysis and estimation of displacement and bending moment for the full-height abutment on pile foundations through soft soils. The results of study shown that SAPA method achieved a good match with test data and results of Plaxis 3D. Thus, the results of this study are intended to provide some guidelines for designer and to bring a more realistic sight into the mechanism of interaction in the design process.
On the standards for investigation, assessment and classification of technical condition of buildings and construction works (pp.84-88)
A/ Prof. NGUYEN XUAN CHINH
Up to now, the investigation, assessment and classification of the technical condition of houses and building constructions have been being interested in by the Management organizations and the consulting units in construction field as well. Some technical instruction manuals and standards have been being compiled in order to improve the construction quality management and to ensure the safety for the building constructions during operation and utilization. This paper presents some concepts, the synchronism and the main contents that should be carried out in the investigation, assessment and classification of the technical situation of houses and building constructions.
