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1
Deierlein, Gregory G. "New Provisions for the Seismic Design of Composite and Hybrid Structures." Earthquake Spectra 16, no. 1 (February 2000): 163–78. http://dx.doi.org/10.1193/1.1586089.
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While there have been significant advances in the design and construction of composite steel-concrete building structures, their use in regions of high seismicity has been hindered by the lack of design criteria in building codes and specifications. This has prompted initiatives in the Building Seismic Safety Council and the American Institute of Steel Construction to develop seismic design provisions for composite structures. The 1997 edition of the AISC Seismic Provisions includes a new section with requirements for composite steel-concrete structures that are cross-referenced by the general seismic loading and design criteria in the 1997 NEHRP Provisions and the 2000 International Building Code (final draft). Intended to complement existing provisions for steel, reinforced concrete and composite structures in the AISC-LRFD Specification and the ACI 318 Building Code, these new provisions provide an important resource for seismic design of composite structural systems, members, and connections.
2
Shekar, Vimala, Samer H. Petro, and Hota V. S. GangaRao. "Fiber-Reinforced Polymer Composite Bridges in West Virginia." Transportation Research Record: Journal of the Transportation Research Board 1819, no. 1 (January 2003): 378–84. http://dx.doi.org/10.3141/1819b-48.
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Fiber-reinforced polymer (FRP) composites have been used more often over the past decade than before in new construction as well as in repair of deteriorated bridges. Many of these bridges are on low-volume roads, where they receive very little attention. It is imperative that new bridge construction or repair be long lasting, nearly maintenance free, and as economical as possible. Relative to those factors, FRP composite bridges have been found to be structurally adequate and feasible because of their reduced maintenance cost and limited environmental impact (i.e., no harmful chemicals leaching into the atmosphere with longer service life). In West Virginia, 23 FRP composite bridges have been constructed, among which 18 are built on low-volume roads that have an average daily traffic (ADT) of less than 1,000, including 7 with ADT less than 400. General FRP composite bridge geometry and preliminary field responses are presented as are some of the preliminary construction specifications and cost data of FRP composite bridges built on low-volume roads in West Virginia
3
Essen, Donald, and Ryza Nur Rohman. "Comparative Analysis of Plate Girder Designs In The Composite Bridge Between AASHTO LRFD Bridge Design Specifications 2017 Regulation with SNI 1729: 2015." Journal of Applied Science, Engineering, Technology, and Education 1, no. 1 (July 10, 2019): 24–39. http://dx.doi.org/10.35877/454ri.asci1143.
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In the world of construction there are various methods and types of materials used to support the passage of a construction work. One of them is composite girder plate. Composite girder plate is one of the many construction methods that combine two construction materials that are physically different in nature, namely concrete with steel. This type of composite girder plate construction is commonly used for bridge construction work with a fairly large span and width. In its use, of course, it must be preceded by stages of careful planning on a standard and valid basis as well. In the following research will discuss and look for similarities and differences regarding the two types of rules in the planning of composite girder plates, namely the rules of planning composite girder plates using AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS 2017 with SNI 1729: 2015. After doing the initial stages of modeling using CSI Bridge software using the profile cross section constraints of the AASHTO provisions, the internal force obtained is Moment Force (Mu) of 3469.13 kNm and Shear Force (Vu) of 225.98 kNm. Then proceed with the analysis of calculations with the help of Microsoft Excel software namely calculating using the AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS 2017 regulations for stability requirements of strong boundary conditions on the bending requirements. Then a Nominal Moment (ØMn) value of 6420.19 kNm is obtained. Then proceed to calculate the same planning constraints, but this time using SNI 1729: 2015 regulations. Obtained Nominal Moment Value (ØMn) of 6579.88 kNm. Then it can be concluded that the two regulations produce a safe and strong planning, of course in accordance with applicable regulations namely: Moment (Mu <ØMn).
4
Liu, Yan Yan, Li Qun Hu, and Zhong Wen Huang. "Application Study of the Geotextile - Graded Gravel - Geomembrane Composite Drainage Layer in Subgrade Construction." Advanced Materials Research 255-260 (May 2011): 3171–75. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.3171.
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The moisture content of subgrade soil increase will lead to soil strength and modulus decrease, the thesis proposes geotextile - graded gravel - geomembrane composite drainage layer solution, for raw materials in different areas, proposes different composite drainage layer layout scheme, and the technical specifications requirements of raw materials. Test section is constructed, analyses the composite drainage layer construction technology carefully, and humidity sensors are planted in the drainage layer, in which the test data show that: after setting the composite drainage layer, subgrade moisture is less affected by seasonal rainfall, humidity change is always in a lesser extent, water stability of the subgrade is increased significantly.
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M. P., Iwundu,. "Construction of Modified Central Composite Designs for Non-standard Models." International Journal of Statistics and Probability 7, no. 5 (August 8, 2018): 95. http://dx.doi.org/10.5539/ijsp.v7n5p95.
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The use of loss function in studying the reduction in determinant of information matrix due to missing observations has effectively produced designs that are robust to missing observations. Modified central composite designs are constructed for non-standard models using principles of the loss function or equivalently first compound of (I ) matrix associated with hat matrix . Although central composite designs (CCDs) are reasonably robust to model mis-specifications, efficient designs with fewer design points are more economical. By classifying the losses due to missing design points in the CCD portions, where there are multiple losses associated with specified CCD portions, the design points having less influence may be deleted from the full CCD. This leads to a possible increase in design efficiency and offers alternative designs, similar in the structure of CCDs, for non-standard models.
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Lu, Pengzhen, Changyu Shao, and Renda Zhao. "LINEAR ANALYSIS AND SIMULATION OF INTERFACIAL SLIP BEHAVIOUR FOR COMPOSITE BOX GIRDERS." Journal of Theoretical and Applied Mechanics 44, no. 1 (March 1, 2014): 79–96. http://dx.doi.org/10.2478/jtam-2014-0005.
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Abstract The slip at the steel-concrete interface in steel-concrete composite beams was studied analytically and numerically. A theoretical description for steel-concrete composite box beams with partial shear interaction based on the partial interaction theory was derived, and equilibrium of the rotation angle w′ was introduced to allow convenient computation of deformation of composite box beams. Numerical simulations of steel-concrete composite box beams subjected to concentrated load and/or uniformly distributed load were conducted. The analytical solutions show excellent agreement with the numerical results. For typical composite box beams used in practice, shear slip in partial composite box beams makes a significant contribution to beam deformation. Even for full composite box beams, slip effects may result in stiffness reduction. However, slip effects are ignored in many design specifications which use transformed section methods; an exception is the American Institute of Steel Construction [1] specifications, which recommend a calculation procedure in the commentary. Finally, the proposed method was extended to analyze the interface slip for shear connectors of different pitch and, to some extent, confirm the accuracy of the predictions.
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Doroshenko, Ya V., V. A. Kucheriaviy, N. M. Andriishyn, S. M. Stetsiuk, and Yu M. Levkovych. "Modern Technologies of the Construction of Field Oil-and-Gas Pipelines." Prospecting and Development of Oil and Gas Fields, no. 3(72) (September 30, 2019): 19–31. http://dx.doi.org/10.31471/1993-9973-2019-3(72)-19-31.
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Foreign experience in the construction of industrial pipelines of flexible composite pipes for the transportation of hydrocarbons is considered. The expediency of using such pipes in the gas-oil complex of Ukraine is substantiated. The designs of flexible composite pipes are described, a brief description of their construction materials is given, the advantages of these pipes over steel ones are considered. The largest manufacturers of flexible composite pipes are listed and the technical specifications of their products are indicated.
Schemes and methods for laying flexible composite pipelines are considered. The technology of preparing flexible composite pipes for transportation is described and the means used for handling are given.
The requirements as to trenching for laying single and multi-stranded flexible composite pipelines are described. The article presents the technologies and tools used to unwind flexible composite pipes from reels and coils before laying them. The methods of connecting flexible composite pipes to each other and to technological equipment, steel pipes, and Xmas-trees are analyzed. The designs of union fittings are considered and the technology of their installation is described. The authors consider methods, technologies and requirements for laying flexible composite pipelines in a trench, their ground laying and laying at the point where the flexible composite pipe exits to the ground for attachment to a steel pipe or technological equipment. The article presents the features of laying flexible composite pipelines through highways, water barriers and swamps by both trench and trenchless technologies, features of trenchless reconstruction of defective, worn steel pipelines with flexible composite pipes, and features of pigging flexible composite pipes and their trying out.
8
Changlong, Yang, Zhang Hongzhi, Wang Wei, Li Yueyue, Han Rongzhuan, and Dong Qiang. "Application of Pre-stranded Tensile Clamp for Aluminum Composite Carbon Fiber Core." E3S Web of Conferences 136 (2019): 01013. http://dx.doi.org/10.1051/e3sconf/201913601013.
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The growth of electricity demand has put forward higher requirements for transmission line performance. Aluminum composite carbon fiber cores (ACCC) has better performance than traditional steel core aluminum conductor and can better meet the requirements of power transmission and transformation field. However, at present, the wedge-shaped self-locking tension clamp is usually used for aluminum composite carbon fiber cores, which is complicated in construction technology and poor in economy, which restricts the promotion and application of aluminum composite carbon fiber cores.In order to solve the above problems, three kinds of tension clamp structures applied to different specifications of aluminum conductors composite core are optimized. Through the strength and grip test of the clamp, it is verified that the grip force of the clamp structure designed can reach 95% of the rated tensile strength of the conductor. Finally, through the comparative analysis of construction and installation, it is concluded that the pre-twisted tension wire clamp designed has a good economic effect.
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Weed, Richard M. "Development of Composite Quality Measures." Transportation Research Record: Journal of the Transportation Research Board 1712, no. 1 (January 2000): 103–8. http://dx.doi.org/10.3141/1712-13.
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Statistical construction specifications based on multiple quality characteristics frequently use pay equations that include a separate term for each of the quality characteristics so that the resultant pay adjustment is a function of the combined effect of all quality measures. An alternate method that can be used to accomplish the same purpose is to base the pay equation on a single quality measure that is a composite of the individual quality measures. The latter approach, because it keys the various decision-making steps to a single performance indicator, simplifies the procedure and offers several practical advantages. It is believed that this approach makes significant strides toward the ultimate goal of developing quality assurance procedures that are at the same time technically sound, fair and effective, and easy to understand and apply. Examples of a two-variable case for hot-mix asphalt pavement and a general three-variable case are presented.
10
Bujnak, Jan, Peter Michalek, and Wieslaw Baran. "Experimental and theoretical investigation of composite truss beams." MATEC Web of Conferences 174 (2018): 04001. http://dx.doi.org/10.1051/matecconf/201817404001.
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The design specifications of composite trusses are only partially included in the European standards. However this construction system can be considered as one of the most economical for building and bridge structures. To create an interaction between steel and concrete, it is necessary to prevent the relative slip at the steel and concrete interface using the shear connectors. But the local effects of a concentrated longitudinal shear force between steel truss chord and concrete slab, as special task, should be appropriately examined. The finite element analyses can be used to investigate numerically this structural system behaviour, exploiting several computer procedures. The experimental research has tested these procedures. The outputs of this study are presented in the paper.
11
Vladimirov, Victor, and Ioan Bica. "Methodology and calculation model for recycling of composite construction products." E3S Web of Conferences 85 (2019): 07016. http://dx.doi.org/10.1051/e3sconf/20198507016.
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The circular economy development has increased awareness on how construction products are treated at the end-of-life stage (EoL). With a growing recognition of the finite nature of primary resources, manufacturing processes are being shifted from the traditional take-make-dispose approach to a greater holistic practice, where valuable and/or scarce substances are recovered at the end of a product’s life. Life Cycle Assessment (LCA) is gaining wider attractiveness, as assessment of environmental impacts constitutes an effective quantitative decision tool to identifying sustainable solutions. At the same time, existing guidelines, technical specifications and methods for LCA assessment at EoL are rather heterogeneous regarding modelling and calculation of related secondary material and energy streams. For construction products, category rules for Environmental Product Declarations (EPD) according to EN 15804 (issued through the European Committee for Standardization) and the Product Environmental Footprint (PEF) (developed by the European Commission) currently represent the most advanced methodological references. The study presents the methodological approach per EN 15804, describing the benefits and loads beyond the typical disposal stage. Thus, the environmental impacts of a construction element can be credited in accord to its material and energetic recycling potential. An applied model is realized for water pipes made of composite material. The calculation is exemplified and comparative results of allocation scenarios per EN 15804 and PEF are discussed, demonstrating correlations between the normative requirements and their application. The results support further identification, assessment and ranking of recycling alternatives (i.e. mechanical, thermal, chemical).
12
Mansor, M. R., S. M. Sapuan, E. S. Zainudin, A. A. Nuraini, and A. Hambali. "Rigidity Analysis of Kenaf Thermoplastic Composites Using Halpin-Tsai Equation." Applied Mechanics and Materials 548-549 (April 2014): 29–33. http://dx.doi.org/10.4028/www.scientific.net/amm.548-549.29.
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In this paper, the stiffness mechanical property of natural fiber reinforced thermoplastic composites is analyzed using composite micromechanical model. Kenaf natural fiber is selected as the reinforcement material in the composites construction while three types of commonly used automotive grade thermoplastic matrices, namely polypropylene, acrylonitrile butadiene styrene and polyamide 6 were selected to be reinforced with kenaf fibers. Their stiffness property was later analyzed using Halpin-Tsai micromechanical model at varying fiber content and fiber aspect ratio conditions. In all cases, theoretical results show that the kenaf reinforced thermoplastic composites stiffness increased linearly as the fiber contents were increased. Apart from that, results also show that the stiffness property also increases as the fiber aspect ratio was increased. Higher final composites stiffness property was also observed as stiffness matrix material is utilized in the composites formulation. The prediction results also provided valuable and quick insight as well as cost effective alternative to composite designers in assessing the stiffness performance of natural fiber composites especially those which are reinforced with thermoplastic matrices compared to conventional experimental technique for automotive product development purposes in addition to identifying the optimal parameter to be put into focus in their composites design to achieve the intended design performance specifications.
13
Gillespie, J. W., D. A. Eckel, W. M. Edberg, S. A. Sabol, D. R. Mertz, M. J. Chajes, H. W. Shenton, et al. "Bridge 1-351 over Muddy Run: Design, Testing, and Erection of an All-Composite Bridge." Transportation Research Record: Journal of the Transportation Research Board 1696, no. 1 (January 2000): 118–23. http://dx.doi.org/10.3141/1696-52.
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Bridge 1.351 on Business Route 896 in Glasgow, Delaware, was replaced with one of the first state-owned all-composite bridges in the nation. Composites are lightweight construction materials that do not corrode, which results in benefits such as ease of construction and reduced maintenance costs. A summary of the design, large-scale testing, fabrication, erection, and monitoring of this bridge is presented. The bridge was designed to AASHTO load and resistance factor design specifications. A methodology was developed to incorporate the engineering properties of these unique composite materials into the design. The bridge consists of two 13 × 32 ft (3.96 × 9.75 m) sections joined by a unique longitudinal joint. The sections have sandwich construction consisting of a core [28 in. (71.12 cm) deep] and facesheets [0.4 to 0.6 in. (10.16 to 15.24 mm) thick] that provide shear and flexural rigidity, respectively. The composite bridge was fabricated with E-glass preforms and vinyl-ester resin, which offers excellent structural performance and long-term durability. Each of the sections was fabricated to near-net shape in a single step by a vacuum-assisted resin transfer molding process. The overall structural behavior has been accurately predicted with simple design equations based on sandwich theory for anisotropic materials. Large-scale testing of full-sized subcomponents was conducted to prove that the design satisfied deflection, fatigue, and strength limit states. A redundant longitudinal joint was designed that consisted of both an adhesively bonded vertical joint between sections and splice plates. Assembly procedures were developed, and transverse testing of the full-sized joint was conducted. Final bridge sections were proof-tested to the strength limit state. The construction phase included section positioning, joint assembly, and application of a latex-modified concrete wear surface. The bridge was reopened to traffic on November 20, 1998. Results from the long-term monitoring effort will be documented.
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Yanful, Ernest K., Michael D. Riley, Mark R. Woyshner, and Jim Duncan. "Construction and monitoring of a composite soil cover on an experimental waste-rock pile near Newcastle, New Brunswick, Canada." Canadian Geotechnical Journal 30, no. 4 (August 1, 1993): 588–99. http://dx.doi.org/10.1139/t93-051.
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A 130 cm thick composite soil cover was constructed on an experimental waste-rock pile at the Heath Steele mine site near Newcastle, New Brunswick. The cover consisted of a 30 cm thick sand base, a 60 cm thick compacted glacial till, a 30 cm thick granular layer, and a final 10 cm thick gravel layer for erosion protection. The till was compacted on the sand base in three finished lifts each of 20 cm thickness. Results of a preconstruction pad test indicated six passes of a 5-t vibratory compactor were required to attain the design specifications of 95% of the Modified Proctor maximum dry density at a moulding water content of 2–3% wet of the optimum. These compaction specifications also ensure that the till has a degree of water saturation of at least 95%, which is required to reduce oxygen and acid fluxes in the underlying pile. Quality control measures were taken during the construction to ensure the specifications were followed. Monitoring instrumentation was installed during the construction of the cover. Results indicate a reduction in gaseous oxygen concentrations in the pile from 20% before cover to about 3% after cover placement. The decreased oxygen penetration implies reduced oxygen flux and acid production. Volumetric water contents averaged about 32% in the till both immediately following cover installation and 7 months later. The water-content data are corroborated by soil-suction measurements. Temperatures in the pile have decreased following cover installation but appear to be more influenced by climatic variability than by a decrease in heat production and hence sulphide mineral oxidation. Observed discharge from two lysimeters, installed below the cover, indicates infiltration of 2–2.5% of precipitation during a 55-day period when rainfall was heavy. The quality of seepage from the pile has not changed since cover installation. Further monitoring will be required to confirm the reduction in acid production. Key words : waste-rock pile, acid generation, soil cover, suction, oxygen flux, percolation.
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Miao, Xin Le, Yong Yao, Yu Wang, and Yun Peng Chu. "Experimental Research on the Sound Insulation Property of Lightweight Composite Paper Honeycomb Core Wallboard." Advanced Materials Research 189-193 (February 2011): 1334–39. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.1334.
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lightweight composite paper honeycomb core wallboard as green building materials and low carbon product of modern life, its lightweight and energy saving, environmental protection, easy construction which other wallboards can't reach, but in actual use, the residents reflects its sound insulation performance is not very well, The lightweight composite paper honeycomb core wallboardand is composite with two rigid panel and paper honeycomb core which is in the middle of the wallboard. However, at present, people rarely Study on Sound Insulation Property of lightweight composite paper honeycomb core wallboard, so take the lightweight composite paper honeycomb core wallboard as the research object, through several sets of Different Specifications wallboard of experiment test,, the results showed that:The sound isolation property of calcium silicate panel is better than Gesso panel’s. The thick panel’s sound isolation property is better than the thin one. At the same thickness, the more layers of paper honeycomb core, the better sound isolation effect. Increase the layer number of paper honeycomb core has remarkable effect on sound isolation property.
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Tao, N., X. Li, and Jin Ping Lu. "Recent Development and Application of Polymers in Concrete Technology in Singapore." Advanced Materials Research 1129 (November 2015): 102–12. http://dx.doi.org/10.4028/www.scientific.net/amr.1129.102.
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Polymer has been extensively used in construction in Singapore during the past few decades and has become a necessary component of some building materials including polymer modified cement mortar, epoxy or Polyurethane (PU) floor screed and injection materials, and fiber-reinforced plastic (FRP) materials. Compare with conventional concrete, polymer concrete composites may achieve remarkable advantages, such as high tension, high flexural strength, high ductility, ability to absorb energy, and high resistance to chemical attack, corrosion, freezing and thawing, and consequently gain more research interest for the scientific community. There are numerous possibilities for incorporation of these materials, such as latex, natural resources, fibers, nanomaterials and laminates. The presence of polymer makes it suitable for wide applications. The various categories of polymer concrete composites are widely used in Singapore’s public and private projects. To ensure and maintain the high standards of the building quality, independent testing and inspection plays a very important role. The present paper reviews recent research and development activities, and applications of polymer concrete composites in Singapore. The innovations and new approaches are reviewed. The development of the requirements and specifications for various polymer concrete composite products are described and discussed. The effect of different factors on the polymer concrete composite and material selection are also described. In addition, the paper also outlines the methods and measures used to inspect and control the quality of application.
17
Li, Mao Hua, Jing Bo Yang, and Zheng Li. "Latest Developments of Materials Used in Transmission Tower Structure." Advanced Materials Research 250-253 (May 2011): 4038–41. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.4038.
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This paper discusses the status quo and development trend of transmission tower materials, points out that there will be higher requirements on the varieties and specifications of transmission tower material alongside the continuous construction of power grids. Tower materials will develop in the environmental-friendly, high-strength and conservation-oriented trend. In the future, the demand for Q420, Q460 high-strength and large-width angle steel will grow enormously; the steel tubular tower will be used in transmission lines more widely due to its excellent carrying capability; new materials like weathering cold-formed steel and composite material will be gradually used in transmission towers.
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Zhou, Jian, Xudong Zhi, Feng Fan, Anliang Jiao, and Hongliang Qian. "Experimental and numerical investigation on failure behavior of ring joints in precast concrete shear walls." Advances in Structural Engineering 23, no. 1 (July 29, 2019): 118–31. http://dx.doi.org/10.1177/1369433219864296.
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Precast shear wall structures have been widely used due to their outstanding features, and the joints between precast members play a critical role in complete structures, specifically for vertical joints. The ring joint is a new connection method used for the vertical connection. Few studies and related regulations were traced; therefore more detailed studies are required. In order to study the anchoring performance and failure behavior, an experimental model was designed and tested under monotonic axial loading, taking the composite height of ring rebars, concrete specifications, diameter of the horizontal rebars, relative position of the ring rebars, diameter of the ring rebars, and number of horizontal rebars into consideration. The failure phenomena were observed and the data were collected. The failure pattern, bearing capacity, yield ratio, displacement ductility coefficient, and other performance parameters were analyzed. The study indicated that the failure patterns are divided into ring rebar pull-out and ring rebar fracture. Increasing the composite height of the ring rebar, the concrete specifications and the number of horizontal rebars could improve the bearing performance, and the contribution of the horizontal rebar diameter was limited, and interlocking ring rebars arranged uniformly are not optimal. In the case of joint failure, the yield ratio is relatively small and the displacement ductility coefficient is larger, which shows the bearing capacity reserve is better. A numerical model was established to analyze the internal behavior, and the results were in good agreement with the experimental results, important for us to understand the failure behavior. Design recommendations will promote its application.
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Aripov, Daler N., Ivan L. Kuznetsov, and Marat A. Salakhutdinov. "Bearing capacity of pultrusion fiberglass gusset sheets in frame structures." Vestnik MGSU, no. 8 (August 2020): 1115–25. http://dx.doi.org/10.22227/1997-0935.2020.8.1115-1125.
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Introduction. At present, design and construction of all-composite structures with the use of pultrusion fiberglass profiles (PFP) are developing. The bearing capacity of all-composite structures is often limited by their node connections. Over the last two decades, many studies have been devoted to the operation of fiber-reinforced polymer (FRP) element nodes connected at right angles (or in the direction of pultrusion and across it). Frame construction nodes are formed by adjoining frame elements at different angles to the bands through gusset sheets. In accordance with the literature analysis, a small number of tests have been carried out to investigate connections at angles to the pultrusion direction. Existing design solutions of gusset sheets in FRP frame structures are mainly made of steel or composite material produced using other technologies (compaction method, pressure treatment method). This study focuses on the implementation of a node connection on unidirectional gusset sheets in which the fibers are positioned at the angle of 0°. Taking into account the specific features of the material, the gusset sheet design in frame structures has been adapted to the properties of pultrusion fiberglass. The purpose of this study is to increase the efficiency of PFP gusset sheet use in frame structures based on the specifications of this material.
Materials and methods. The adaptive method was used when designing the node connection design on the frame structure gusset sheets. The material of the trapezoidal steel truss is changed to the composite material while retaining the original design solution. Subsequently, the structure is upgraded to take into account the properties and features of the composite material.
Results. The main results of the study involve determining the factor of safety of pultrusion fiberglass at different angles to the direction of force. In order to increase the bearing capacity of the element node connection, various gusset plate design solutions are provided, which take into account different forces in the frame structure elements.
Conclusions. When designing PFP constructions, features of the material must be taken into account. Replacing traditional materials with composite without adjusting the design layout and upgrading the structure leads to increased material intensity.
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Muñoz-Ruiperez, Carmelo, Francisco Fiol Oliván, Verónica Calderón Carpintero, Isabel Santamaría-Vicario, and Ángel Rodríguez Sáiz. "Mechanical Behavior of a Composite Lightweight Slab, Consisting of a Laminated Wooden Joist and Ecological Mortar." Materials 13, no. 11 (June 5, 2020): 2575. http://dx.doi.org/10.3390/ma13112575.
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The investigation reported in this paper is an evaluation of the mechanical behavior of full-scale ecological mortar slabs manufactured with a mixture of expanded clay and recycled concrete aggregates. The composite mortars form a compressive layer over laminated wooden joists to form a single construction unit. To do so, full-scale flexural tests are conducted of the composite laminated wood-ecological mortar slabs with different types of mortar designs: reference mortar (MR), lightweight mortar dosed with recycled concrete aggregates (MLC), and lightweight mortar dosed with recycled mixed aggregates (MLM). The test results showed that the mortar forming the compression layer and the laminated wooden joists worked in unison and withstood a higher maximum failure load under flexion than the failure load of the wooden joists in isolation. Moreover, the laboratory test results were compared with the simulated values of the theoretical model, generated in accordance with the technical specifications for structural calculations contained in the Spanish building code, and with the results calculated by a computer software package. From the analysis of the results of the calculation methods and the full-scale laboratory test results, it was concluded that the safety margin yielded by the calculations validated the use of those methods on this type of composite slab. In this way, a strong mixed wood–mortar slab was designed, contributing little dead-load to the building structure and its manufacture with recycled aggregate, also contributes to the circular economy of construction materials.
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Lazzari, P. M., A. Campos Filho, F. P. S. L. Gastal, R. A. Barbieri, and R. C. Schwingel. "Automation of the evaluation of bonded and unbonded prestressed concrete beams, according to brazilian and french code specifications." Revista IBRACON de Estruturas e Materiais 6, no. 1 (February 2013): 13–54. http://dx.doi.org/10.1590/s1983-41952013000100003.
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This paper presents a suggestion for the automation of the design procedures of bonded and unbonded prestressed concrete flexural members, according to the Brazilian (NBR 6118:2007) and French (Règles BPEL 91) norm specifications. Prestressing of concrete structures has been increasingly used, mainly due to its building advantages, as well as allowing reducing crack incidence and element dimensions by the use of more resistant materials. Structure is analyzed by a numerical model that employs a hybrid type finite element for planar frames, considering geometric nonlinearity, cyclic loading and composite construction. The computational algorithm implemented considers full, partial and limited prestressing situations, evaluating in each case decompression limit state, limit state of cracking, ultimate limit state and final prestressing state. Finally, two examples comparing design situations according to the Brazilian and French norms are presented.
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Thai, Huu-Tai, Trung-Kien Nguyen, Seunghye Lee, Vipulkumar Ishvarbhai Patel, and Thuc P. Vo. "Review of Nonlinear Analysis and Modeling of Steel and Composite Structures." International Journal of Structural Stability and Dynamics 20, no. 04 (April 2020): 2030003. http://dx.doi.org/10.1142/s0219455420300037.
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Structural steel frames exhibit significantly geometric and material nonlinearities which can be captured using the second-order inelastic analysis, also known as advanced analysis. Current specifications of most modern steel design codes, e.g. American code AISC360, European code EC3, Chinese code GB50017 and Australian code AS4100 permit the use of advanced analysis methods for the direct design of steel structures to avoid tedious member capacity checks. In the past three decades, a huge number of advanced analysis and modeling methods have been developed to predict the behavior of steel and composite frames. This paper presents a comprehensive review of their developments, which focus on beam-column elements with close attention to the way to capture geometric and material nonlinearity effects. A brief outline of analysis methods and analysis tools for frames was presented in the initial part of the paper. This was followed by a discussion on the development of displacement-based, force-based and mixed beam elements with distributed plasticity and concentrated plasticity models. The modeling of frames subjected to fire and explosion was also discussed. Finally, a review of the beam-column models for composite structures including concrete-filled steel tubular (CFST) columns, composite beams and composite frames was presented.
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BRITTO, G. F. J., V. S. SILVA, and J. P. GONÇALVES. "Experimental analysis of longitudinal shear of composite slabs." Revista IBRACON de Estruturas e Materiais 13, no. 3 (June 2020): 515–42. http://dx.doi.org/10.1590/s1983-41952020000300005.
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Abstract The composite concrete slab systems with steel-deck incorporated has become an alternative to conventional slab models, since it often does not require the use of shoring, promoting several constructive practices, beyond operation of the reinforcement as a positive moment. The procedure of verification of composite slabs is based on the semi-empirical method m and k. The purpose of this paper was to investigate the application of the "m-k method" in a group of slabs with alternative dimensions as the usually adopted in the tests, even as to correlate the values obtained with the results found when testing the models as proposed by the ANSI 2011 test standard, since the normative method is costly and expensive. Therefore, four-point flexural tests were performed on slab models considering only one deck module, varying two spans, the same procedure was repeated in slabs with usual construction dimensions (normative models). The linear regression method was applied to the data found in order to obtain the parameters that would be analyzed. The main results show that the alternative model with the adopted dimensions does not present values that can be applied directly to the normative models, since the increase of the shear span reduces in a significant way the theoretical resistance of the slabs. Nevertheless, the values for the m and k obtained of both alternative and normative models can be adopted confidently as part of the sizing process of the respective models. The deviations between theoretical and experimental resistance satisfy the specifications of the ANSI 2011 standard for both models helped in the confirmation of the previous statement. The expectation of this paper is to assist in the search for new procedures for determining parameters m and k.
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Belarbi, A., M. Reda, P. Poudel, H. Tahsiri, M. Dawood, and B. Gencturk. "Prestressing Concrete with CFRP Composites for Sustainability and Corrosion-Free Applications." MATEC Web of Conferences 149 (2018): 01010. http://dx.doi.org/10.1051/matecconf/201814901010.
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Advancement in material science has enabled the engineers to enhance the strength and long-term behavior of concrete structures. The conventional approach is to use steel for prestressed bridge girders. Despite having good ductility and strength, beams prestressed with steel are susceptible to corrosion when subjected to environmental exposure. The corrosion of the prestressing steel reduces load carrying capacity of the prestressed member and result in catastrophic failures. In the last decades, more durable composite materials such as Aramid Fiber Reinforced Polymer (AFRP), Glass Fiber Reinforced Polymer (GFRP) and Carbon Fiber Reinforced Polymer (CFRP) have been implemented in concrete structures as a solution to this problem. Among these materials, CFRP stands out as a primary prestressing reinforcement, which has the potential to replace steel and provide corrosion free prestressed bridge girders. Despite its promise, prestressing CFRP has not frequently been used for bridge construction worldwide. The major contributing factor to the lack of advancement of this promising technology in the United States (U.S.) is the lack of comprehensive design specifications. Apart from a limited number of guides, manuals, and commentaries, there is currently no standard or comprehensive design guideline available to bridge engineers in the U.S. for the design of concrete structures prestressed with CFRP systems. The main goal is to develop design guidelines in AASHTO-LRFD format for concrete bridge girders with prestressing CFRP materials. The guidelines are intended to address the limitation in current AASHTO-LRFD Bridge Design Specifications which is applicable for prestressed bridge girders with steel strands. To accomplish this goal, some of the critical parameters that affect the design and long-term behavior of prestressed concrete bridge girders with prestressing CFRP systems are identified and included in the research work. This paper presents preliminary results of an experimental study that is part of a National Highway Co-operative Highway Research Program (NCHRP) project.
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Hsueh, Lily, Stuart Bretschneider, Justin M. Stritch, and Nicole Darnall. "Implementation of sustainable public procurement in local governments: a measurement approach." International Journal of Public Sector Management 33, no. 6/7 (August 10, 2020): 697–712. http://dx.doi.org/10.1108/ijpsm-09-2019-0233.
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PurposeAssessing and measuring the extent of organization-level policy implementation has received little scholarly attention, especially in the areas of local governments' procurement and environmental protection. To rectify the paucity of research in this area, this paper adopts Leonard-Barton's (1988) conceptualization of the misalignment between the (policy) innovation and the organization and draws on an original survey of local government finance, environment and public works departments in a representative sample of US cities with at least 25,000 residents to develop a strategy for measuring the extent of the implementation of a sustainable procurement policy (SPP) in local governments.Design/methodology/approachThe authors demonstrate through the construction of a composite index that in order for a SPP to be fully implemented, standards and rules, routines and decision-making criteria need to exist to reconcile any technical, infrastructural and decision-making misalignments between the new policy and an organization's pre-existing norms and routines.FindingsThe authors empirically assess and demonstrate that the paper's proposed composite measure of policy implementation is robust to multiple specifications and measurement reliability and construct validity tests.Originality/valueWhereas the existing literature from political science and policy science has tended to focus on higher levels of implementation in government through a complex hierarchical system, this paper underscores the importance of the policy implementation at the organizational level. Moreover, the authors contribute methodologically by our development of a strategy to measure the extent of the implementation of a SPP by local governments.
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Sharma, Natalia. "Study on Retrofitting and Strengthening of Reinforced Concrete Beams Using Fibrous Concrete." International Journal for Research in Applied Science and Engineering Technology 9, no. 8 (August 31, 2021): 1676–84. http://dx.doi.org/10.22214/ijraset.2021.37637.
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Abstract: Reinforced concrete structures are frequently in need of repair and strengthening as a result of numerous environmental causes, ageing, or material damage under intense stress conditions, as well as mistakes made during the construction process. RC structures are repaired using a variety of approaches nowadays. The usage of FRC is one of the retrofitting strategies. Steel fiber reinforced concrete (SFRC) was used in this investigation because it contains randomly dispersed short discrete steel fibers that operate as internal reinforcement to improve the cementitious composite's characteristics (concrete). The main rationale for integrating small discrete fibers into a cement matrix is to reduce the amount of cement used. The principal reason for incorporating short discrete fibers into a cement matrix is to reduce cracking in the elastic range, increase the tensile strength and deformation capacity and increase the toughness of the resultant composite. These properties of SFRC primarily depend upon length and volume of Steel fibers used in the concrete mixture. In India, the steel fiber reinforced concrete (SFRC) has seen limited applications in several structures due to the lack of awareness, design guidelines and construction specifications. Therefore, there is a need to develop information on the role of steel fibers in the concrete mixture. The experimental work reported in this study includes the mechanical properties of concrete at different volume fractions of steel fibers. These mechanical properties include compressive strength, split tensile strength and flexural strength and to study the effect of volume fraction and aspect ratio of steel fibers on these mechanical properties. However, main aim of the study was significance of reinforced concrete beams strengthened with fiber reinforced concrete layer and to investigate how these beams deflect under strain. The objective of the investigation was finding that applying FRC to strengthen beams enhanced structural performance in terms of ultimate load carrying capacity, fracture pattern deflection, and mode of failure or not.
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Lu, Jin Ping. "Review on Application of Polymer Concrete in Singapore." Advanced Materials Research 687 (April 2013): 416–25. http://dx.doi.org/10.4028/www.scientific.net/amr.687.416.
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Singapore is a small island country, but has won renown as uncorrupted government and high quality products. Independent testing and inspection played a very important role for this achievement[1]. The Housing and Development Board (HDB) is the sole public authority in Singapore and was set up as a statutory on 1 February 1960. Within 45 years, it built more than 700,000 flats housing approximately 86% of the population. Every year, around 40,000 new flats (about 400 blocks) are built up to meet the demands. In March 1992, HDB launched the 15-year main upgrading programme (MUP) to vying the finishes and facilities of old estates up to the standard of those in the new towns. The upgrading programme is a conscious effort by the government to provide a better living environment, strengthen existing community ties and enhance the value of our flats. The potential size of the upgrading program is approximately 370,000 units spread across 20 years, which works out to be 350 blocks per year. To ensure and maintain the high standards of the housing quality, Polymer concrete materials including polymer modified cement mortar, epoxy or PU floor screed and injection materials, and fibre-reinforced plastic (FRP) materials are extensively used in the new and upgrading projects. In this paper, the various applications of polymer concrete composites in Singapore are described and discussed. The various categories of polymer concrete composites are extensively used in Singapore’s public and private projects. To ensure and maintain the high standards of the building quality, independent testing and inspection plays a very important role. Through implementing a quality control program to ensure high standards in product quality and performance requirements, Housing & Development Board (HDB), Singapore's public housing authority and statutory board under the Ministry of National Development, screens and provides a comprehensive selection of quality products needed for HDB construction projects through HDB's Materials List [2] with a set of product evaluation requirement. The development of the requirements and specifications for various polymer concrete composite products are also described and discussed
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Fauzi, A. Rizki, and Markawie Markawie. "DESIGN OF COMPOSITE GIRDER STRUCTURE BRIDGE OF SELUANG-1 RIVER PT LIFERE AGRO KAPUAS, KAPUAS DISTRICT." CERUCUK 4, no. 1 (June 7, 2021): 1. http://dx.doi.org/10.20527/crc.v4i1.3576.
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The bridge at the Seluang-1 river is located around the palm oil plantation land owned by PT Lifere Agro Kapuas, Kapuas Regency, Central Kalimantan. In this Seluang-1 river, a bridge is planned to be built to facilitate the mobilization of palm oil plantation crops and other matters as well as transportation in the PT Lifere Agro Kapuas area because before there was a bridge the transportation traffic was cut off by the river so it had to circle quite a long way. The bridge is designed as a bridge with composite girder structure type. The methodology in the design of loading uses the SNI 1725-2016 concerning on the Loading Standards for Bridges and SNI 2833-2016 concerning on the Earthquake Resilience Planning Standards for Bridges. For methodology in designing concrete structures refer to SNI 2847-2013 concerning Structural Concrete Requirements for Buildings and methodology in designing steel structures refers to SNI 1729-2015 concerning Specifications for Structural Steel Buildings. The material used for abutment uses reinforced concrete material. The methodology in calculating the bearing capacity of the foundation uses the method by Mayerhof and also the method by Kazuto Nakazawa, while the methodology in calculating the lateral bearing capacity uses the Broms method, with the efficiency of the pile using a graph by O’Neill. From the results of topographic measurements taken a bridge design with a span of 30 m with a total bridge width of 7 m. The slab design is 25 cm thick with the compressive strenght of concrete is fc’ 30 MPa (K-350). The steel girder beam used WF Profile 1350.800.100.130 and the diaphragm beam used WF Profile 250.125.6.9 with BJ55 steel quality (fy 410 MPa). Whereas in the lower structure, the abutment designed with a height of 350 cm, a width of 320 cm and a length of 850 cm, was used with compressive strenght of concrete is fc’ 30 MPa (K-350). In the foundation used Spun Pile type piles with a diameter of 60 cm with a depth of 30 m piling as much as 8 piles on one abutment. Obtained Qallow = 116,37 tons > Qload = 114,69 tons so that the foundation is declared safe. The planned budget for the construction of a bridge on the Seluang-1 river is Rp 8.990.566.000,00.-
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Baca, Bart, Mohammad Al-Sarawi, and Timothy W. Kana. "RECENT BIOREMEDIATION RESULTS ON OIL SPILLED DURING THE 1991 GULF WAR1." International Oil Spill Conference Proceedings 2005, no. 1 (May 1, 2005): 793–96. http://dx.doi.org/10.7901/2169-3358-2005-1-793.
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ABSTRACT Over thirteen years ago, Iraqi soldiers caused the release of over 10 million barrels of oil into Arabian Gulf waters from various sources. The oil impacted the majority of the western Gulf shoreline, estimated at over four hundred miles. Coastal development is having to deal with oil which was buried, stock-piled, or otherwise left in place. One such development is underway at Al Khiran (southern Kuwait) where oil is within planned construction areas for public beaches, housing lots, a marina, and channels. Although the oil is weathered and generally considered non-toxic (based on chemical analyses below), expanses of it pose physical and esthetic problems for construction and human use of the areas. Tests were performed using various means of treating this oil, and the results are given herein. A variety of bioremediation methods was tested, including the use of products from four companies, selected at random from the oil spill chemical industry (U.S. and abroad). All four were bacterial powders, with nutrients included or added separately, applied according to manufacturers' specifications. Test plots were on mildly contaminated soil (33 mg/kg total hydrocarbons) which had oil mixed throughout. Plots were located in the upper intertidal zone, where they were exposed to minimal (<30 cm), diurnal, high tide flooding, and the research site was protected from wave and wind action by a levee. Extreme conditions at the sites included high temperatures, lack of rainfall, and flushing by high salinity seawater (40 parts per thousand salt). Sites were sampled before treatment, and at various times beginning 44 days after treatment. Composite samples were collected from each test plot and analyzed for total petroleum hydrocarbons (TRPH), and for three hydrocarbon ranges: C8–C10, C10–C28, and C28–C40. Results showed no significant reduction in total hydrocarbons by any product, compared to pre-treatment levels. Aggressive physical tilling of contaminated soils at a second site provided some reduction in total hydrocarbons during this period. Various methods were tried in the next phase of testing, including additional product exposure time, increased tilling, and screening. The results provide guidelines for the use of chemical products and physical treatments, in extreme coastal conditions, for the treatment of weathered hydrocarbons.
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Lin, Wu-Ting, Chung-Yu Chen, Ching-Chang Lee, Cheng-Chen Chen, and Shih-Chi Lo. "Air Phthalate Emitted from Flooring Building Material by the Micro-Chamber Method: Two-Stage Emission Evaluation and Comparison." Toxics 9, no. 9 (September 9, 2021): 216. http://dx.doi.org/10.3390/toxics9090216.
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The phthalate and semi-volatile organic compounds (SVOCs) are modern chemical substances and extensively existing in the indoor environment. The European Commission stipulated the “European Unified Test Criteria”, since 2011, for the declared specifications of building products (CEN/TS 16516), based on the “lowest concentrations of interest (LCI)”, the index pollutants, test method, and emission standard of “phthalate” and “SVOC” were specified in detail. The purpose of this study is to use six common indoor floor construction products in Taiwan (regenerated pseudoplastic rubber flooring, healthy pseudoplastic imitation wood floor, regenerated pseudoplastic rubber flooring, PVC floor tile/floor, plastic click floor, composite floor covered with carpet) to detect the changes in the concentration of phthalate emitted to the air. The ISO 16000-25 Indoor air—Part 25: Determination of the emission of semi-volatile organic compounds by building products—micro-chamber method is used to build a DS-BMEMC (glass micro-chamber: volume 630 mL), the SVOC, including phthalate, is collected in two stages, in the stable conditions of temperature 25 °C, relative humidity 50% and air change rate 2 times/h, the Stage 1 emission detection experiment (24 h) is performed, and then the Stage 2 heating-up desorption emission detection experiment (40 min air sampling) is performed, the temperature rises to 200–220 °C, the phthalate and SVOC adsorbed on the glass micro-chamber is desorbed at a high temperature to catch the air substances, the air is caught by Tenax®—TA and Florisil® adsorption tube, and then the GC/MS and LC/MSMS analysis methods are used for qualitative and emission concentration analyses of SVOC of two-stage emission, respectively. The findings show that the floor construction materials emit nine phthalate SVOCs: DEHP, DINP, DNOP, DIDP, BBP, DBP, DIBP, DEP, and DMP, the two-stage emission concentrations are different, Stage 1 (normal temperature) emission concentration of six floor construction materials is 0.01–1.2% of Stage 2 (high temperature) emission concentration, meaning the phthalate SVOC of floor construction materials is unlikely to be volatilized or emitted at normal temperature. An interesting finding is that only S3 was detected DINP 72.6 (μg/m3) in stage 1. Others were detected DINP in stage 2. This might be because S3 has carpet on the surface. This implies that floor material with carpet may have an emission of DINP at normal temperature. The result of this study refers to the limited value evaluation of EU structural material standard emission TSVOC ≤ 0.1 ug/m3, the floor building material emissions are much higher than the evaluation criteria, increasing the health risk of users. The detection method and baseline can be used as the standard for controlling the emission of phthalate SVOC of Taiwan’s green building material labeling system in the future.
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Talavira, Nataliia. "Constructionist basis of composing and translating political speeches: A case study of President Trump’s inaugural address." SHS Web of Conferences 105 (2021): 03006. http://dx.doi.org/10.1051/shsconf/202110503006.
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Application of the principles and tenets of cognitive linguistics to translation studies rests on the assumption that both of them employ the same meaning process while working with a text. Procedures implemented to translate the inaugural address of American President Trump have been regarded from the point of view of Construction Grammar. The construction is viewed as the main translation unit representing source linguistic material below the level of the text. The paper singles out from the translation of President Trump’s inaugural address equivalent constructions with identical form and meaning and non-equivalent pairings indicating transformations of structure or semantics in the original constructions. Syntactical modifications include the change of word order, grammar tenses or omission of construction component, while lexical transformations result in generalization, carried out by words with more abstract meaning than those in the source construction; simplification, representing separate objects or features from the array of denoted in the source pairing; and specification accentuating and detailing particular entities.
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Leon, Roberto T. "Recent Developments in Composite Construction in the USA." Advances in Structural Engineering 8, no. 3 (July 2005): 259–74. http://dx.doi.org/10.1260/1369433054349114.
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This paper presents an overview of the proposed changes in composite design provisions for the upcoming American Institute of Steel Construction (AISC) 2005 Specification. The main change insofar as member design is concerned relates to how composite column design is handled. The new provisions will provide a more smooth transition between design of composite and reinforced concrete columns and a more rational, mechanistically-based design procedure. Insofar as member detailing is concerned, the main change is in the strength values for shear studs, which have been considerably lowered under some circumstances. The paper also presents some ongoing developments in composite floor and lateral load resisting systems, and concludes with a short description of an unusual composite truss.
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Leon, Roberto T. "The new 2005 AISC specification." Rem: Revista Escola de Minas 60, no. 2 (June 2007): 241–50. http://dx.doi.org/10.1590/s0370-44672007000200006.
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In late 2005, the American Institute of Steel Construction issued its most recent Specification for Structural Steel Buildings (ANSI/AISC 360-05). This specification includes updated design provisions in both allowable strength design (ASD) and load and resistance factor design methods (LRFD), and incorporates the design provisions for hollow structural sections and single angles. Amongst the major changes are a complete revamping of the methodologies for assessing stability of framed structures, new provisions for composite columns and updated material requirements. This paper will describe the changes and highlight those of practical significance.
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McKinnon, Mark B., Yan Ding, Stanislav I. Stoliarov, Sean Crowley, and Richard E. Lyon. "Pyrolysis model for a carbon fiber/epoxy structural aerospace composite." Journal of Fire Sciences 35, no. 1 (November 21, 2016): 36–61. http://dx.doi.org/10.1177/0734904116679422.
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Carbon fiber laminate composites have been utilized in the aerospace industry by replacing lightweight aluminum alloy components in the design of aircraft. By replacing low flammability aluminum components by carbon fiber laminates, the potential fuel load for aircraft fires may be increased significantly. A pyrolysis model has been developed for a Toray Co. carbon fiber laminate composite. Development of this model is intended to improve the understanding of the fire response and flammability characteristics of the composite, which complies with Boeing Material Specification 8–276. The work presented here details a methodology used to characterize the composite. The mean error between the predicted curves and the mean experimental mass loss rate curves collected in bench-scale gasification tests was calculated as approximately 17% on average for heat fluxes ranging from 40 to 80 kW m−2. During construction of the model, additional complicating phenomena were investigated. It was shown that the thermal conductivity in the plane of the composite was approximately 15 times larger than the in-depth thermal conductivity, the mass transport was inhibited due to the high density of the laminae in the composite, and oxidation did not appear to significantly affect pyrolysis at heat fluxes up to 60 kW m−2.
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HU, Zhaohui. "Application of Multi-objective Optimization of Multi-material-multi-part Specification Composite Construction." Journal of Mechanical Engineering 46, no. 22 (2010): 111. http://dx.doi.org/10.3901/jme.2010.22.111.
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JACKSON, ETHAN K. "A Module System for Domain-Specific Languages." Theory and Practice of Logic Programming 14, no. 4-5 (July 2014): 771–85. http://dx.doi.org/10.1017/s1471068414000337.
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AbstractDomain-specific languages(DSLs) are routinely created to simplify difficult or specialized programming tasks. They expose useful abstractions and design patterns in the form of language constructs, provide static semantics to eagerly detect misuse of these constructs, and dynamic semantics to completely define how language constructs interact. However, implementing and composing DSLs is a non-trivial task, and there is a lack of tools and techniques.We address this problem by presenting a complete module system over LP for DSL construction, reuse, and composition. LP is already useful for DSL design, because it supports executable language specifications using notations familiar to language designers. We extend LP with a module system that is simple (with a few concepts), succinct (for key DSL specification scenarios), and composable (on the level of languages, compilers, and programs). These design choices reflect our use of LP for industrial DSL design. Our module system has been implemented in theformulalanguage, and was used to build key Windows 8 device drivers via DSLs. Though we present our module system as it actually appears in ourformulalanguage, our emphasis is on concepts adaptable to other LP languages.
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Boal-San Miguel, Iván, and Luis César Herrero-Prieto. "Reliability of Creative Composite Indicators with Territorial Specification in the EU." Sustainability 12, no. 8 (April 11, 2020): 3070. http://dx.doi.org/10.3390/su12083070.
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There is wide consensus regarding the capacity of the creative economy as a factor in economic development and sustainability in regions in the medium term, and it is an issue that has aroused interest in measuring the creative potential of areas by estimating composite indicators. Most works posit indicators by countries or cities and normally employ a single aggregation method. This work proposes the construction of a synthetic indicator of creativity with regional disaggregation for a wide sample of European countries, comparing different aggregation methods under the hypothesis of the benefit of the doubt (BoD). We use Eurostat data and also analyse spatial dependence processes. Findings point to an inequality in the regional distribution of creativity in Europe and this reveals creative gap models in areas, suggesting that creativity triggers greater spatial disparities wherever it is found. The principal creative clusters are located in regions in central and northern Europe, particularly in regions with national capitals. The regional distribution of the indicator evidences positive spatial dependence, thereby revealing the existence of spatial externalities that provide feedback for the concentration process and, therefore, a widening of the disparities.
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Jia, Rui Hui, Yun Wei Chen, Yuan Qing Wang, Liang Zong, Jun Li, and Xi Min Zhang. "The Overall Optimization of Djoué Composite Steel-Concrete Bridge in the Congo (Brazzaville) National Road One Phase- II Project." Applied Mechanics and Materials 256-259 (December 2012): 1520–27. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.1520.
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In order to learn more about the composite steel-concrete bridge which the Djoué bridge of Congo (Brazzaville) National Road One Phase- II Project has selected, promote the design technologies of bridges and better understand and improve the relevant standards, The overall optimization design analysis of Djoué Bridge aiming at saving steel and improving bearing capacity is necessary. The Doctor Bridge was used in optimization of bridge type, concrete thickness and height of steel beam and they have been selected. It can provide technical references for the construction of the Djoué Bridge, the follow-up study of the composite steel-concrete bridge and the specification improvement.
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Bank, Lawrence C., T. Russell Gentry, Benjamin P. Thompson, and Jeffrey S. Russell. "A model specification for FRP composites for civil engineering structures." Construction and Building Materials 17, no. 6-7 (September 2003): 405–37. http://dx.doi.org/10.1016/s0950-0618(03)00041-2.
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Shahawy, Mohsen, Thomas E. Beitelman, and Omar Chaallal. "Construction Considerations for Repair of Bridges with Externally Bonded Fiber-Reinforced Plastic Material." Transportation Research Record: Journal of the Transportation Research Board 1740, no. 1 (January 2000): 164–69. http://dx.doi.org/10.3141/1740-21.
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A recent advancement in the field of structural rehabilitation consists of fiber-reinforced plastic (FRP) composites used to strengthen structural elements. Since a significant portion of the infrastructure in North America is in need of a rapidly applied strengthening and rehabilitation solution, much interest in this method has developed. FRP systems provide the advantage of increasing ductility and shear and flexural strength, whereas they are lightweight and can be applied relatively quickly and easily. Guidelines that the engineer can use to recommend construction specifications involved in FRP applications are provided. The results are based on numerous field applications and will help provide an efficient and proper repair method.
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Peng, Jun, Dong Xiu Zhang, and Wen Bai Yu. "Pre-Test on the Behaviors of Vertical Prestressed Spacing to Composite Masonry Walls with Holes from the Aspect of Eccentrical Compression." Applied Mechanics and Materials 578-579 (July 2014): 113–20. http://dx.doi.org/10.4028/www.scientific.net/amm.578-579.113.
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Based on the eccentric compression performance testing of the out-of-planes of 4 pieces of different pre-stressed composite masonry walls with holes and constructional columns, the pre-stress’s influences on the horizontal and vertical transmission and distribution, emergence and development of cracks, deformation of the components and fracture morphology and mechanism of the section stress along composite wall with holes are revealed. The testing shows that the pre-stress not only improves comprehensively the load-carrying properties of composite wall, but its fracture mechanism and mechanical model are the same as that of the non-pre-stressed composite wall, so that the same design approach can be used. And it provides further experimental basis to supplement and improve the basic theory and computation methods of eccentric compression of composite wall’s out-of-plane in the current masonry structure specifications. Only crack resistance and bearing capacity are studied in this article.
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Qiu, Yi Mei, Sen Yuan Wen, and Jun Xiang Chen. "CF60 Concrete Composition Design and Application on Fudiankou Xijiang Super Large Bridge." E3S Web of Conferences 38 (2018): 03005. http://dx.doi.org/10.1051/e3sconf/20183803005.
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Guangxi Wuzhou City Ring Road Fudiankou Xijiang super large bridge CF60 concrete is a new multi-phase composite high-performance concrete, this paper for the Fudiankou Xijiang bridge structure and characteristics of the project, in accordance with the principle of local materials and technical specification requirements, combined with the site conditions of CF60 engineering high performance concrete component materials, proportion and the technical performance, quantify the main physical and mechanical performance index. Analysis main influencing factors of the technical indicators, reasonable adjustment of concrete mix design parameters, and the use of technical means of admixture and multi-function composite admixture of concrete, obtain the optimal proportion of good work, process, mechanical properties stability and durability of engineering properties, recommend and verification of concrete mix; to explore the CF60 high performance concrete Soil in the Fudiankou Xijiang bridge application technology, detection and tracking the quality of concrete construction, concrete structure during the construction of the key technology and control points is proposed, evaluation of CF60 high performance concrete in the actual engineering application effect and benefit to ensure engineering quality of bridge structure and service life, and super long span bridge engineering construction to provide basis and reference.
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Maxwell, Daniel T., and Dennis M. Buede. "Composing and constructing value focused influence diagrams: a specification for decision model formulation." Journal of Multi-Criteria Decision Analysis 12, no. 4-5 (July 2003): 225–43. http://dx.doi.org/10.1002/mcda.360.
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Palise, Frank, Brian J. Strizki, and Richard M. Weed. "Upgrading the Asphaltic Concrete Specification of the New Jersey Department of Transportation." Transportation Research Record: Journal of the Transportation Research Board 1616, no. 1 (January 1998): 1–5. http://dx.doi.org/10.3141/1616-01.
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An earlier upgrading of New Jersey’s specification for in-place air voids in asphaltic concrete pavement was made to strengthen the acceptance procedure and incorporate several advances in specification-writing technology. Modifications included changing to percent defective as the quality measure, switching to an equation-type pay schedule, adding a bonus provision for superior work, and including a remove-and-replace clause for seriously defective work. Changing from an acceptance procedure based on the sample mean to one based on percent defective essentially redefined the acceptable quality level from a percent defective value of 50 to a considerably more demanding value of 10. To allow the construction industry a chance to become familiar with this new requirement, a relaxed form of the pay schedule was initially adopted. Industry has subsequently had extensive experience with the new specification and the New Jersey Department of Transportation is now preparing to modify the specification further to provide an even stronger incentive to produce high-quality pavement. The modifications were developed by a joint task force representing the construction industry and the New Jersey Department of Transportation and include increasing the bonus provision, retaining the present pay schedule for quality that is only marginally deficient, changing to a more steeply descending pay schedule for seriously defective quality, and adding a more elaborate retest procedure to ensure that substantial pay reductions, when they occur, are truly warranted. In addition to controlling air voids, the new acceptance procedure also combines requirements for thickness and smoothness into a single composite pay equation. Operating characteristic curves are presented to demonstrate the capability of the new procedure.
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Liu, Jiang, Yongjian Liu, Lei Jiang, and Ning Zhang. "Long-term field test of temperature gradients on the composite girder of a long-span cable-stayed bridge." Advances in Structural Engineering 22, no. 13 (May 29, 2019): 2785–98. http://dx.doi.org/10.1177/1369433219851300.
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Bridges are inevitably affected by daily, seasonal and annual air temperature and solar radiation. The thermal effects on bridges, especially for long-span cable-stayed bridges with composite girders, are significant and complicated. The evaluation of temperature distribution has been a primary concern to bridge engineers and researchers. This article presents a more than one-year temperature database of a long-span cable-stayed bridge with a small cantilever length-to-web depth ratio in the composite girder. Uniform temperature, linear temperature difference, thermal curvature, and self-equilibrated thermal stress are considered to imply the characteristics of the temperature distribution in such composite girders. Two profiles (profile 1 and profile 2) for positive vertical temperature gradient and one profile (profile 3) for negative vertical temperature gradient are proposed. The extreme temperature differences with a 100-year return period are determined for each profile with extreme value analysis. Among the three profiles, profile 2 is unique for composite girders with a small cantilever length-to-web depth ratio. Based on parametric studies, profile 2 is revised with the cantilever length-to-web depth ratio for wide applications. Finally, comparisons of vertical temperature gradients are made between the investigated composite girder and the recommendations in Chinese Specification.
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Xia, Yong Jun, Wen Ming Mei, Yu Jing Hao, and Da Ni. "Analysis and Design of Lifting Pole Made of Carbon-Fiber Reinforced Resin Matrix Composites." Applied Mechanics and Materials 723 (January 2015): 71–75. http://dx.doi.org/10.4028/www.scientific.net/amm.723.71.
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As a special lifting device, the lifting pole is widely used in construction of transmission line powers. Due to the special working environment, a new-type lifting pole made of carbon-fiber reinforced resin matrix composites is designed to facilitate transportation and usage. It is shown by comparison of material properties that new materials can greatly reduce structural self-weight on the condition of ensuring mechanical properties. In order to ensure the equipment is used safely and reliably, this paper carries out mechanical calculation and ANSYS finite element analysis by setting up a mechanical model, and the results show that the design is reasonable and accords with national relevant specifications.
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Xiao, Liang Li, Xiao Yu, and Jian Wei Han. "Analysis on Axial Compression Bearing Capacity of Steel Reinforced Concrete Sandwich Node." Applied Mechanics and Materials 501-504 (January 2014): 685–89. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.685.
Full textAbstract:
According to the limit values of axial compression ratio of steel reinforced concrete given by technical specification for steel reinforced concrete composite structure (JGJ138-2001), the axial force of steel reinforced concrete sandwich nodes calculated by MIDAS and the axial bearing capacity calculated by limit values of axial compression ratio are compared with an actual project. The results show that steel concrete columns with designed strength of C60, the strength more than of column concrete strength higher than C50 is the least requirement as to meet the axial compression ratio. The result provides a theoretical basis for the future of safety work and the sandwich joint construction.
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Fan, Jing Jing. "Behavior of Geosynthetic Clay Liners due to the Migration of Heavy Metal." Advanced Materials Research 989-994 (July 2014): 433–36. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.433.
Full textAbstract:
To protect the underlying soil and groundwater from landfills, the landfills are commonly lined with layered liner systems. Geosynthetic clay liners (GCL) have been increasingly used in the landfill liner systems to substitude the traditional compacted clay liners (CCL) because of their low cost, easily construction behavior and low leakage rate. To study the behavior of the GM+GCL liner system used in China due to the migration of Pb2+, we introduce in detail GM+GCL liner systems proposed by the Chinese specification. Then one dimensional finite layer model is used to investigate the anti-pollution behavior of the CM+GCL composite liner systems, with the focuses on the heavy metal Pb2+. It could be concluded that the main migration way through the GM+GCL composite liner system is that the transport of Pb2+through a GM+GCL composite liner system of a landfill cover takes place primarily through the holes in the GM. The findings provide useful reference for preventing, controlling and treating groundwater pollution in the GM+GCL liner system technically and scientifically.
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Wang, Jun, and Zhi Wei Sun. "Application and Design of the New Steel Fiber RPC Column-Template without Demolition." Applied Mechanics and Materials 120 (October 2011): 288–91. http://dx.doi.org/10.4028/www.scientific.net/amm.120.288.
Full textAbstract:
Innovation of material and function represents the direction of contemporary architecture template development. Based on the study results of domestic and foreign building templates, a new type of template structure—Steel fiber RPC (reactive powder concrete) column-template without demolition is presented taking account of the characteristics of template materials and construction methods. Compared with the traditional template, the new one takes composite material and function innovation as a breakthrough. It improves efficiency of construction while the column-template forms the outer surface of the decorative grass-roots which expands the scale of the function of column template. This paper introduces the material selection and illustrates the calculation of the new template. Based on the existing design specification of template, new design recommendation of template thickness is proposed through theoretical analysis and simulation, which provides a theoretical basis of steel fiber RPC column template without demolition in engineering applications.
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Dan, Jingpei, Wenbo Guo, Weiren Shi, Bin Fang, and Tingping Zhang. "Deterministic Echo State Networks Based Stock Price Forecasting." Abstract and Applied Analysis 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/137148.
Full textAbstract:
Echo state networks (ESNs), as efficient and powerful computational models for approximating nonlinear dynamical systems, have been successfully applied in financial time series forecasting. Reservoir constructions in standard ESNs rely on trials and errors in real applications due to a series of randomized model building stages. A novel form of ESN with deterministically constructed reservoir is competitive with standard ESN by minimal complexity and possibility of optimizations for ESN specifications. In this paper, forecasting performances of deterministic ESNs are investigated in stock price prediction applications. The experiment results on two benchmark datasets (Shanghai Composite Index and S&P500) demonstrate that deterministic ESNs outperform standard ESN in both accuracy and efficiency, which indicate the prospect of deterministic ESNs for financial prediction.