Tài liệu miễn phí Kiến trúc - Xây dựng
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Xây dựng công thức thực nghiệm xác định hệ số ảnh hưởng của mũi hắt sóng đến lưu lượng tràn qua đê biển có tường đỉnh
Bài viết này nêu lên thực trạng lưu lượng tràn qua đỉnh đê có tường đỉnh không chỉ phụ thuộc vào độ lưu không Rc, độ dốc và độ nhám mà còn phụ thuộc vào vị trí, chiều cao và đặc điểm của mũi hắt sóng. Mời các bạn cùng tham khảo!
10/10/2021 8:09:15 AM +00:00
Ảnh hưởng của một số phụ gia hóa dẻo, chậm đông kết đến các tính chất cơ lý của bê tông đầm lăn sử dụng cho đập trọng lực
Bài viết này nghiên cứu sử dụng phụ gia phụ gia hóa dẻo, chậm đông kết Plastiment TM25 của hãng Sika, Rheoplus 26 RCC (A1) của hãng BASF và ADVA 181 của hãng GRACE cho bê tông đầm lăn thi công đập trọng lực. Bê tông đầm lăn đảm bảo các yêu cầu kỹ thuật về cường độ, tính công tác, thời gian đông kết, tính chống thấm cho công trình. Mời các bạn cùng tham khảo!
10/10/2021 8:09:02 AM +00:00
Nghiên cứu sự tương tác giữa kết cấu - đất nền cho mố cầu được xây dựng trên móng cọc qua nền đất yếu từ mô phỏng số 3D
Bài viết này phân tích mố cầu chắn nền đắp cao với phần mềm số sẵn có thông qua phương pháp phần tử hữu hạn và các mô hình đất cải tiến. Các dữ liệu về thí nghiệm centrifuge được sử dụng như một nguồn kết quả tham khảo. Mời các bạn cùng tham khảo!
10/10/2021 8:08:44 AM +00:00
Kiểm định và quan trắc cầu bê tông cốt thép bằng phương pháp IADP sử dụng sóng âm thanh (Acoustic emission) – quy trình triển khai
Bài viết này giới thiệu giải pháp kiểm định và quan trắc công trình cầu bê tông cốt thép bằng phương pháp IADP (Identification of Active Damage Processes - Xác định các quá trình phá hoại chủ động) dựa trên phân tích các tín hiệu sóng âm thanh (Acoustic Emission – AE) được tạo bởi chính quá trình phá hoại dưới tác động của tải trọng khai thác. Mời các bạn cùng tham khảo!
10/10/2021 8:08:26 AM +00:00
Nghiên cứu dự báo và đánh giá ảnh hưởng của khoảng tĩnh không đối với các công trình biển nổi có kể đến hiệu ứng phi tuyến bậc hai của tải trọng sóng
Bài viết này nghiên cứu dự báo và đánh giá ảnh hưởng của khoảng tĩnh không đối với các công trình biển nổi (Semi-submmersible, TLP,...) bằng cách thực hiện tính toán tuyến tính trong miền tần số sử dụng phần mềm HydroStar (Research Department – Bureau Veritas, 2014) và áp dụng phương pháp “Stokes 2nd order correction” đề xuất bởi (Bert Sweetman, 2002) là một phương pháp hiệu chỉnh kể đến ảnh hưởng của những hiệu ứng phi tuyến bậc hai. Mời các bạn cùng tham khảo!
10/10/2021 8:03:53 AM +00:00
A 3-D finite element modeling for the textile-reinforced concrete plates under tensile load using a non-linear behaviour for cementitious matrix
The stress jumps in reinforcement textile after each crack was also observed and analyzed. In comparison with the experiment, a good agreement between both results was found for all cases of this study. A parametric study could show the effect of the length and position of the measurement zone on the stress-strain curve of TRC’s mechanical behavior.
10/10/2021 6:16:22 AM +00:00
Simulation of several flying situations of paragliders
This article represents the mathematical modeling and simulation of several common flying situations of a paraglider through establishing and solving the governing differential equations in state-space. Those flying situations include the ones with constant headwind/tailwind with or without constant upwind; the ones with different scenario for the variations of headwind and tailwind combined with the upwind; the ones with varying pilot mass; and the ones whose several parameters are in the form of interval quantities. The simulations were conducted using a powerful Julia toolkit called DifferentialEquations.jl. The obtained results in each situation are discussed, and some recommendations are presented.
10/10/2021 6:15:41 AM +00:00
A bubble-enhanced quadrilateral finite element for estimation bearing capacity factors of strip footing
In this paper, a computational approach using a combination of the upper bound theorem and the bubbleenhanced quadrilateral finite element (FEM-Qi6) is proposed to evaluate bearing capacity factors of strip footing in cohesive-frictional soil. The new element is built based on the quadrilateral element (Q4) by adding a pair of internal nodes to solve the volumetric locking phenomenon.
10/10/2021 6:15:34 AM +00:00
Optimization of construction site layout using dynamic hybrid bacterial and ant colony algorithm
This research proposes a new Hybrid Meta-heuristic model which is a combination of Ant Colony Optimization algorithm (ACO), Bacterial foraging algorithm (BFA), and Pair-Wise Exchange Heuristic algorithm (PWEH). The proposed algorithm is named Dynamic Hybrid Ant Colony Algorithm (DHACA) model that can enhance local and global searches simultaneously. In addition, parameter values are optimized to create a better solution. This research also demonstrates the effectiveness of DHACA compared with the previous studies such as Multi-objectives Genetic Algorithm (MOGA), Simulated Annealing Algorithm based Multi-objectives Genetic Algorithm (SAbased MOGA) on the CSLP. DHACA supports the construction site dynamic planning with constraints on facilities to improve work efficiency.
10/10/2021 6:15:19 AM +00:00
Applying the noncooperative game model for compensation concept in contractor selection process for large-scale projects
The experiment results have demonstrated the owner can gain benefit by using rational compensation. The sensitivity analysis also shows the interest correlation between the owner and bidders. By choosing a proper strategy based on Nash Equilibrium solutions, both the owner and bidders can reach to win-win situation.
10/10/2021 6:15:12 AM +00:00
Prediction of axial strength in circular steel tube confined concrete columns using artificial intelligence
This study applied 136 samples of short and intermediate STCC columns infilled with normal strength concrete, high strength concrete, or ultimate high strength concrete to evaluate the AI models. Compressive strengths of concrete cylinders was ranged from 23.20 Mpa to 188.10 Mpa. The AI models were assessed by statistical indexes including MAPE, MAE, RMSE, and R.
10/10/2021 6:15:05 AM +00:00
Mechanical properties of bituminous mixtures under sinusoidal cyclic loadings: Experiment and modelling
Mechanical behaviour of bituminous mixtures is characterized by the great thermal sensitivity and the large viscous effects. This paper focuses on the linear viscoelastic (LVE) behaviour of bituminous mixtures that is considered for pavement design. The studied material is a GB3 mix (GB in French is “Grave Bitume”) which is often used for base course construction in France.
10/10/2021 6:14:57 AM +00:00
Numerical analysis of seismic behavior of square concrete filled steel tubular columns
This paper presents a numerical analysis of the seismic behavior of square concrete filled steel tubular (CFST) columns. Finite element analysis (FEA) models in ABAQUS software were used to simulate a series of columns subjected to axial compression and cyclic lateral loading. The CFST columns were simulated using nonlinear tri-dimensional (3-D) finite elements for the infilled concrete, and nonlinear two-dimensional (2-D) finite elements for the steel tube.
10/10/2021 6:14:50 AM +00:00
General non-uniform quadrilateral cross-sections for thin-walled FG sandwich beams
The paper aims at introducing an analysis of thin-walled functionally graded sandwich beams for general nonuniform quadrilateral cross-sections. Generally, the materials are assumed to be graded through the thickness following a predefined shape while Poisson’s ratio kept as a constant due to its less domination. The crosssection linearly varies from one end to another end of the beam.
10/10/2021 6:14:42 AM +00:00
Recycling of waste incineration bottom ash in the production of interlocking concrete bricks
This study presents an experimental investigation on the recycling of waste incineration bottom ash (IBA) as a fine aggregate in the production of interlocking concrete bricks (ICB). Before being used, the concentration of heavy metal in IBA was determined to confirm it is a non-toxic material. In this study, the IBA was used to replace crushed sand (CSA) in the brick mixtures at different replacement levels of 0%, 25%, 50%, 75%, and 100% (by volume).
10/10/2021 6:14:33 AM +00:00
Span length-dependent load-carrying capacity of normal concrete - hpfrc beams
The dependence of load-carrying capacity on span length of beams, which contained a combination of normal strength concrete (NC) - High-performance fiber-reinforced concrete (HPFRC), was investigated in this study. The used HPFRC contained 1.0 vol.% long hooked blended with 0.5% short smooth fibers. Two types of span length were designed as 300 mm and 450 mm while dimensions of beam sections were identical with depth × width of 150 × 150 mm2.
10/10/2021 6:14:25 AM +00:00
Static bending and free vibration analysis of functionally graded porous plates laid on elastic foundation using the meshless method
This paper presents a numerical approach for static bending and free vibration analysis of the functionally graded porous plates (FGPP) resting on the elastic foundation using the refined quasi-3D sinusoidal shear deformation theory (RQSSDT) combined with the Moving Kriging–interpolation meshfree method.
10/10/2021 6:14:15 AM +00:00
An isogeometric formulation with a three-variable high order shear deformation theory for free vibration analysis of fg porous plates reinforced by graphene platelets
In addition, the displacement field of THSDT needs the high continuity in approximated formulation with high-order derivatives for a weak form of fourth order equation. According to IGA formulation based on the generalized THSDT, the shear locking phenomenon is free. The variables of THSDT are less than HSDTs which contain five DOFs per node. The influences of weight fractions, the coefficient porosity, dispersion patterns of GPLs and distribution types of porosity on structure’s natural frequencies are studied through some numerical examples. In order to prove the reliability and accuracy of present method, the numerical results are compared to available published works.
10/10/2021 6:14:07 AM +00:00
Understanding the concept of urban village in Hanoi city, Vietnam: Social - spatial - economic interactions with surrounding urban areas
In cities throughout Asian countries, there is an increasingly ubiquitous presence of “urban villages” that reflects the transformation of traditional farming villages into urban places under the impact of rapid urbanization. Hanoi - one of the two biggest cities in Vietnam - has been witnessing the fast changes of rural settlements into urban built environments during the in-situ urbanization process since the 1990s. It is very important to have a comprehensive understanding of the urban village model in the urban development context of Hanoi city.
10/10/2021 6:13:58 AM +00:00
An experimental study on the shear capacity of corroded reinforced concrete beams without shear reinforcement
The effect of corrosion on the structural behavior of reinforced concrete (RC) beams without stirrups was experimentally investigated. A total of eight medium-scale RC beams were constructed without stirrups. The beams were 150 mm in width, 200 mm in depth, and 1100 mm in length. Test variables included three distinct degrees of corrosion (0%, 3.13%, 4.11%, and 4.93% by mass loss of steel rebar). Six beams were subjected to an accelerated corrosion test, while two beams served as non-corroded control beams.
10/10/2021 6:13:42 AM +00:00
Flexural performance of reinforced concrete beams made with locally sourced fly ash
The paper investigates the flexural performance of reinforced concrete beams in which fly ash from Vinh Tan power station was used to replace original Portland cement in the proportions of 0%, 10%, 20% and 40% by weight. Twelve reinforced concrete beams with the dimensions of 100×150 mm in cross section and 1000mm in length were cast and cured in water.
10/10/2021 6:13:33 AM +00:00
Effect of fiber amount and stirrup ratio on shear resistance of steel fiber reinforced concrete deep beams
This paper deals with the effect of steel fiber amounts and the interaction between the fiber amount and stirrup ratio on the shear behavior and capacity of reinforced concrete (RC) deep beams with steel fibers. The experimental program was carried out on twelve deep beams with different fiber amounts (0, 30, 40, and 65 kg/m 3 ) and stirrup ratios (0.1, 0.15, and 0.25%).
10/10/2021 6:13:23 AM +00:00
The influence of saturation on the interface shear strength of clay and nonwoven geotextile
The paper presents a series of modified direct shear tests to investigate the interface shear strength between clay and nonwoven geotextile under different normal stresses and degrees of saturation. The modified direct shear apparatus consists of a 60 mm × 60 mm square shear box assembly with a 60 mm × 60 mm acrylic block inserted in the bottom shear box. A woven geotextile layer was glued to the top of the acrylic block, while the top shear box was filled by the compacted clayey soil.
10/10/2021 6:13:08 AM +00:00
Microstructural characteristics of ultra-high performance concrete by grid nanoindentation and statistical analysis
In this study, grid nanoindentation and statistical deconvolution analysis were applied into a developed Ultrahigh performance concrete (UHPC) to broaden the understanding of the microstructure phases and their mechanical properties. A total of 550 nanoindentation tests was carried out on UHPC and the mechanical properties, including indentation modulus and hardness of the indented material were extracted from nanoindentation load-depth curves.
10/10/2021 6:12:59 AM +00:00
Stress-independent parameters for stress-strain relationship and damping in nonlinear one-dimensional seismic site response analysis
This study developed a set of parameters that can be used to normalize the modulus reduction and damping curves to be stressindependent. The proposed formulations for the stress-independent parameters were implemented in the finite element code SRAP and validated through producing shear modulus reduction and damping curves that match the existed ones.
10/10/2021 6:12:50 AM +00:00
Probabilistic pushover analysis of reinforced concrete frame structures using dropout neural network
This study develops a probabilistic data-driven approach using the Multiple Layer Perceptron network coupled with the Dropout mechanism to perform the pushover analysis of reinforced concrete (RC) frame structures, predicting base shear, lateral displacement, as well as their relationship between the two formers. Moreover, corresponding confidence intervals of predicted values are also available owing to the probabilistic nature of the method, thus helping engineers design conservative solutions.
10/10/2021 6:12:42 AM +00:00
Effects of end-plate on the critical moment of I-section cantilever beam with free end restrained laterally
Effects of end-plate on the lateral buckling of doubly symmetrical I-section cantilever beam with free end restrained laterally are analyzed using the software COMSOL and linear shell finite elements. The torsional stiffness of the end-plate prevents the free warping of flanges and decreases the warping effective length of the cantilever beam. A parametric study is conducted on 3231 cantilever beams under uniform bending to propose an approximative formula to determine the warping effective length factor which depends on the ratio between the torsional constant of the end-plate and the warping stiffness of the beam.
10/10/2021 6:12:33 AM +00:00
Pilot study on assessment of trace metals in PM10 at road sites in Bac Giang province, Vietnam
In this study, characterization of PM10 mass and its trace metals concentration at road sites in Bac Giang province located in the North of Vietnam during two different seasons has been performed. PM10 samples at 11 road sites using the high volume SIBATA HV-500R (Japan) at the flow rate of 400 L/min were collected during 10 hours (from 7:00 to 17:00) at flat low-lying plain, midland, mountain and highland areas.
10/10/2021 6:12:25 AM +00:00
Thông tin Xây dựng cơ bản và khoa học công nghệ xây dựng – Số 21/2013
Thông tin Xây dựng cơ bản và khoa học công nghệ xây dựng – Số 21/2013 giúp các bạn nắm được những thông tin về kinh tế và quản lý xây dựng những vấn đề lý luận và thực tiễn; sự cố công trình xây dựng, nguyên nhân và giải pháp phòng ngừa; quản lý chất lượng và an toàn trong xây dựng...
10/10/2021 6:10:36 AM +00:00
Thông tin Xây dựng cơ bản và khoa học công nghệ xây dựng – Số 2/2013
Thông tin Xây dựng cơ bản và khoa học công nghệ xây dựng – Số 2/2013 được biên soạn nhằm trình bày giải pháp bê tông nhựa polymer trong xây dựng cầu đường của Nga; khảo sát sự phát triển đô thị của khu vực ngoại thành đối với mối qua hệ khu vực nội thành tại một số đô thị lớn và đề xuất các giải pháp khắc phục những tồn tại...
10/10/2021 6:10:29 AM +00:00