scholarly journals PULL-OUT RESISTANCE OF SELF-TAPPING SCREWS IN CROSS-LAMINATED TIMBER MADE FROM RADIATA PINE

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Xin Li ◽  
Mahmud Ashraf ◽  
Mahbube Subhani ◽  
Paul Kremer
Keyword(s):  
Failure Modes ◽  
Construction Materials ◽  
Structural Response ◽  
Radiata Pine ◽  
Raw Material ◽  
Fibrous Materials ◽  
Cross Laminated Timber ◽  
Pull Out ◽  
Traditional Construction ◽  
Penetration Depths

Cross-laminated timber (CLT) is now considered a viable alternative to traditional construction materials both in mid-rise and high-rise structures. The structural response of CLT heavily relies on the type of timber used in manufacturing, and this can vary significantly based on the original source for this naturally grown raw material. Spruce has been widely used in Europe for CLT production, but in Australia, locally available radiata pine is used by XLam for the manufacturing of their CLT panels. Self-tapping screws (STS) are typically recommended by CLT manufacturers and are most commonly used in relevant construction due to their high load carrying capacities and easy installation process. VGS STSs produced by Rothoblaas were used to investigate their composite actions when pulled-out from three-layer XLam CLT panels with thicknesses of 105 mm and 135 mm. VGS screws with 11 mm in diameter were inserted both parallel-to-grain and perpendicular-to-grain on the narrow face of the CLT panels as part of the current study. Typical failure modes as well as critical penetration depths were carefully recorded. Obtained results showed significant increase of pull-out capacity as penetration depths were increased for considered cases. However, experimental results also showed some obvious inconsistencies. These observations clearly demonstrate the challenges associated with working naturally grown fibrous materials and highlights the importance of major research on this field.

scholarly journals Sustainable Cross-Laminated Timber Structures in a Seismic Area: Overview and Future Trends

2021 ◽  
Vol 11 (5) ◽  
pp. 2078
Author(s):  
Antonio Sandoli ◽  
Claudio D’Ambra ◽  
Carla Ceraldi ◽  
Bruno Calderoni ◽  
Andrea Prota
Keyword(s):  
Seismic Performance ◽  
Environmental Sustainability ◽  
State Of The Art ◽  
Construction Materials ◽  
Raw Material ◽  
Seismic Resistance ◽  
Future Trends ◽  
Timber Structures ◽  
Cross Laminated Timber ◽  
Seismic Area

Cross-laminated timber (CLT) buildings are recognized as a robust alternative to heavyweight constructions, because beneficial for seismic resistance and environmental sustainability, more than other construction materials. The lightness of material and the satisfactory dissipative response of the mechanical connections provide an excellent seismic response to multi-story CLT buildings, in spite of permanent damage to timber panels in the connection zones. Basically, CLT constructions are highly sustainable structures from extraction of raw material, to manufacturing process, up to usage, disposal and recycling. With respect to other constructions, the potential of CLT buildings is that their environmental sustainability in the phases of disposal and/or recycling can be further enhanced if the seismic damage in structural timber components is reduced or nullified. This paper reports a state-of-the art overview on seismic performance and sustainability aspects of CLT buildings in seismic prone regions. Technological issues and modelling approaches for traditional CLT buildings currently proposed in literature are discussed, focusing the attention on some research advancements and future trends devoted to enhance seismic performance and environmental sustainability of CLT buildings in seismic prone regions.

Dynamic bearing capacity of point fixed corrugated metal profile sheets subjected to blast loading

2021 ◽  
pp. 204141962110592
Author(s):  
Kai Fischer ◽  
Jan Dirk van der Woerd ◽  
Wilfried Harwick ◽  
Alexander Stolz
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Load Transfer ◽  
Structural Response ◽  
Blast Loading ◽  
Risk And Resilience ◽  
Structural Members ◽  
Pull Out ◽  
Metal Sheets ◽  
Corrugated Metal

Blast loading scenarios and the corresponding hazards have to be evaluated for infrastructure elements and buildings especially at industrial sites for safety and security issues. Point fixed corrugated metal sheets are often applied as façade elements and can become a hazard for humans if they are pulled off. This paper investigates the dynamic bearing capacity of such structural members in terms of their general bending behavior in the middle of the span and pull-out behaviors at the fixing points. The elements are fixed at two sides and the load transfer is uniaxial. An experimental series with static and dynamic tests forms the basis to identify the predominant failure modes and to quantify the maximum stress values that can be absorbed until the investigated structural members fail. The experimental findings are applied to create and to optimize an engineering model for the fast and effective assessment of the structural response. The aim is the derivation of a validated model which is capable to predict the blast loading behavior of metal sheets including arbitrary dimensions, material properties, and screw connections. Results of this study can be integrated into a systematic risk and resilience management process to assess expected damage effects and the evaluation of robustness.

RHEOLOGICAL PROPERTIES OF CERAMIC MASSES: IMPROVEMENT BY COMPLEX MATERIAL ACTIVATION

2019 ◽  
Vol 16 (3) ◽  
pp. 334-351
Author(s):  
A. S. Mavlyanov ◽  
E. K. Sardarbekova
Keyword(s):  
Rheological Properties ◽  
Raw Materials ◽  
Sensitivity Coefficient ◽  
Raw Material ◽  
Clay Material ◽  
Fibrous Materials ◽  
Chemical Production ◽  
Production Wastes ◽  
Pass Through ◽  
The Masses

Introduction. The objective of the research is to study the effect of the complex activation of the alumina raw material on the rheological properties of the ceramic mass. In addition, the authors investigate solutions for the application of optimal coagulation structures based on loams and ash together with plastic certificates.Materials and methods. The authors used the local forest like reserves of clay loams at the BashKarasu, ash fields of the Bishkek Central Heating Centre (BTEC) and plasticizer (sodium naphthenate obtained from alkaline chemical production wastes) as fibrous materials. Moreover, the authors defined technological properties of raw materials within standard laboratory methodology in accordance with current GOSTs.Results. The researchers tested plastic durability on variously prepared masses for the choice of optimal structures. The paper demonstrated the plastic durability of complexly activated compounds comparing with non-activated and mechanically activated compounds. The sensitivity coefficient increased the amount of clay loams by mechanically and complexly activated, which predetermined the possibility of intensifying the process of drying samples based on complexly activated masses.Discussion and conclusions. However, mechanical activation of clay material reduces the period of relaxation and increases the elasticity coefficient of ceramic masses by 1.8–3.4 times, meanwhile decreases elasticity, viscosity and the conventional power during molding, which generally worsens the molding properties of the masses. Сomplex activation of ash-clay material decreases the period of relaxation and provides an increase in elasticity, plasticity of ceramic masses by 46–47%, reduction in viscosity by 1.5–2 times, conventional power on molding by 37–122% in comparison with MA clay loams. Ceramic masses based on spacecraft alumina raw materials belong to the SMT with improved rheological properties; products based on them pass through the mouthpiece for 5–7 seconds.

scholarly journals New directions for reinforced concrete coastal structures

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Steven Nolan ◽  
Marco Rossini ◽  
Chase Knight ◽  
Antonio Nanni
Keyword(s):  
Service Life ◽  
Prestressed Concrete ◽  
Composite Structures ◽  
Construction Materials ◽  
Design Guidelines ◽  
Coastal Structures ◽  
Frp Composites ◽  
The Us ◽  
Time Dependent Effect ◽  
Traditional Construction

AbstractWithin the last century, coastal structures for infrastructure applications have traditionally been constructed with timber, structural steel, and/or steel-reinforced/prestressed concrete. Given asset owners’ desires for increased service-life; reduced maintenance, repair and rehabilitation; liability; resilience; and sustainability, it has become clear that traditional construction materials cannot reliably meet these challenges without periodic and costly intervention. Fiber-Reinforced Polymer (FRP) composites have been successfully utilized for durable bridge applications for several decades, demonstrating their ability to provide reduced maintenance costs, extend service life, and significantly increase design durability. This paper explores a representative sample of these applications, related specifically to internal reinforcement for concrete structures in both passive (RC) and pre-tensioned (PC) applications, and contrasts them with the time-dependent effect and cost of corrosion in transportation infrastructure. Recent development of authoritative design guidelines within the US and international engineering communities is summarized and a examples of RC/PC verses FRP-RC/PC presented to show the sustainable (economic and environmental) advantage of composite structures in the coastal environment.

scholarly journals Microstructure and Mechanical Performance of Resistance Spot Welded Martensitic Advanced High Strength Steel

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1021
Author(s):  
Yunzhao Li ◽  
Huaping Tang ◽  
Ruilin Lai
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Strong Dependence ◽  
High Strength ◽  
Weld Nugget ◽  
Resistance Spot ◽  
Pull Out ◽  
Cross Tension ◽  
Spot Welded

Resistance spot welded 1.2 mm (t)-thick 1400 MPa martensitic steel (MS1400) samples are fabricated and their microstructure, mechanical properties are investigated thoroughly. The mechanical performance and failure modes exhibit a strong dependence on weld-nugget size. The pull-out failure mode for MS1400 steel resistance spot welds does not follow the conventional weld-nugget size recommendation criteria of 4t0.5. Significant softening was observed due to dual phase microstructure of ferrite and martensite in the inter-critical heat affected zone (HAZ) and tempered martensite (TM) structure in sub-critical HAZ. However, the upper-critical HAZ exhibits obvious higher hardness than the nugget zone (NZ). In addition, the mechanical properties show that the cross-tension strength (CTS) is about one quarter of the tension-shear strength (TSS) of MS1400 weld joints, whilst the absorbed energy of cross-tension and tension-shear are almost identical.

scholarly journals Using Satellite Data to Analyse Raw Material Consumption in Hanoi, Vietnam

2021 ◽  
Vol 13 (3) ◽  
pp. 334
Author(s):  
Alessandro Novellino ◽  
Teresa J. Brown ◽  
Tom Bide ◽  
Nguyễn Thị Thục Anh ◽  
Evi Petavratzi ◽  
...  
Keyword(s):  
Satellite Data ◽  
Urban Expansion ◽  
Construction Materials ◽  
Statistical Correlation ◽  
Earth Observation ◽  
Land Conservation ◽  
Raw Material ◽  
Material Consumption ◽  
Sand And Gravel ◽  
Agricultural Areas

In this work, we provide an innovative route for analysing urban expansion and population growth and their link to the consumption of construction materials by combining satellite data with material consumption analysis within the Hanoi Province (Vietnam). Urban expansion is investigated with the use of landcover maps for the period 1975–2020 derived from satellite. During this period, artificial surfaces and agricultural areas have increased by 11.6% and 15.5%, respectively, while forests have decreased by 26.7%. We have used publicly available datasets to calculate and forecast the construction materials consumption and measure its statistical correlation with urban expansion between 2007 and 2018. Our results show that official figures for sand consumption are currently underestimated, and that by 2030, steel and sand and gravel consumption will increase even further by three and two times, respectively. Our analysis uses a new method to assess urban development and associated impacts by combining socio-economic and Earth Observation datasets. The analysis can provide evidence, underpin decision-making by authorities, policymakers, urban planners and sustainability experts, as well as support the development of informed strategies for resource consumption. It can also provide important information for identifying areas of land conservation and ecological greenways during urban planning.

The all-composite road bridge – a proposal for rapid urbanisation

2018 ◽  
Author(s):  
Tomasz Siwowski ◽  
Aleksander Kozlowski ◽  
Leonard Ziemiański ◽  
Mateusz Rajchel ◽  
Damian Kaleta
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Construction Materials ◽  
Fast Growing ◽  
Frp Composites ◽  
Frp Composite ◽  
Reinforced Polymer ◽  
Composite Bridge ◽  
Fibre Reinforced Polymer ◽  
Traditional Construction

<p>Technology and materials can help cities get smarter and cope with rapid urbanisation. Life cycle assessment (LCA) is one of the approaches applied in evaluation of material sustainability. Many significant LCA comparisons of innovative and traditional construction materials indicate that fibre- reinforced polymer (FRP) composites compare very favourably with other materials studied. As a proposal for rapid urbanisation, the FRP all-composite road bridge was developed and demonstrated in Poland. The paper describes the bridge system itself and presents the results of research on its development. The output of the R&amp;D project gives a very promising future for the FRP composite bridge application in Poland, especially for cleaner, resilient and more environmentally efficient infrastructure of fast-growing cities.</p>

Alternative Concrete – Geopolymer Concrete

2021 ◽  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Construction Industry ◽  
Building Material ◽  
Construction Materials ◽  
Raw Material ◽  
Geopolymer Concrete ◽  
Sustainable Solutions ◽  
New Construction ◽  
Alkali Activated

Concrete is the most versatile, durable and reliable material and is the most used building material. It requires large amounts of Portland cement which has environmental problems associated with its production. Hence, an alternative concrete – geopolymer concrete is needed. The general aim of this book is to make significant contributions in understanding and deciphering the mechanisms of the realization of the alkali-activated fly ash-based geopolymer concrete and, at the same time, to present the main characteristics of the materials, components, as well as the influence that they have on the performance of the mechanical properties of the concrete. The book deals with in-depth research of the potential recovery of fly ash and using it as a raw material for the development of new construction materials, offering sustainable solutions to the construction industry.

Failure Modes of Tapered Suction Caissons Under Vertical Pull-Out Loads

2007 ◽  
Author(s):  
Mahmood Nabipour ◽  
Mostafa Zeinoddini ◽  
Mahmood R. Abdi
Keyword(s):  
Failure Modes ◽  
Numerical Approach ◽  
Local Failure ◽  
Superior Performance ◽  
Soil Plug ◽  
Pull Out ◽  
Modes Of Failure ◽  
Numerical Studies ◽  
Second Mode ◽  
Suction Caissons

The pull-out performance of conventional upright suction caissons has been investigated by different researchers. However, no attention has been formerly paid to tapered suction caissons. Some numerical studies already conducted by the authors demonstrated that tapered caissons exhibit pull-out capacities well above than that from their corresponding upright caissons. This paper deals with different failure mechanisms of tapered suction caissons and discusses some reason for their superior performance. A numerical approach has been used and different combinations of caisson types/ soil categories have been examined. With tapered suction caissons two different modes of failure have been discerned. The first mode has been noticed to develop in weak clays and sands under drained conditions. This mode corresponds to a shear sliding failure in the soil plug along the caisson’s interior wall. Concurrently a soil wedge is formed in the soil body adjacent to the caisson. The second mode of failure has been observed in higher strength drained clays and undrained clays and sands. With this failure mode a local failure at the bottom of the soil plug has been noticed to happen. At the same time the failure is extended to the lower surfaces of a soil wedge outside of the caisson. The detached soil plug accompanies the caisson in its movement upward following the local failure.

scholarly journals Treatment of Soil Contaminated by Mining Activities to Prevent Contamination by Encapsulation in Ceramic Construction Materials

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6740
Author(s):  
Juan María Terrones-Saeta ◽  
Jorge Suárez-Macías ◽  
Antonio Bernardo-Sánchez ◽  
Laura Álvarez de Prado ◽  
Marta Menéndez Fernández ◽  
...  
Keyword(s):  
Ceramic Material ◽  
Contaminated Soil ◽  
Toxic Elements ◽  
Construction Materials ◽  
Well Being ◽  
Ceramic Materials ◽  
Potentially Toxic Elements ◽  
Raw Material ◽  
Mining District ◽  
Different Soils

Mining is an essential activity for obtaining materials necessary for the well-being and development of society. However, this activity produces important environmental impacts that must be controlled. More specifically, there are different soils near new or abandoned mining productions that have been contaminated with potentially toxic elements, and currently represent an important environmental problem. In this research, a contaminated soil from the mining district of Linares was studied for its use as a raw material for the conforming of ceramic materials, bricks, dedicated to construction. Firstly, the contaminated soil was chemically and physically characterized in order to evaluate its suitability. Subsequently, different families of samples were conformed with different percentages of clay and contaminated soil. Finally, the conformed ceramics were physically and mechanically characterized to examine the variation produced in the ceramic material by the incorporation of the contaminated soil. In addition, in this research, leachate tests were performed according to the TCLP method determining whether encapsulation of potentially toxic elements in the soil occurs. The results showed that all families of ceramic materials have acceptable physical properties, with a soil percentage of less than 80% being acceptable to obtain adequate mechanical properties and a maximum of 70% of contaminated soil to obtain acceptable leachate according to EPA regulations. Therefore, the maximum percentage of contaminated soil that can be incorporated into the ceramic material is 70% in order to comply with all standards. Consequently, this research not only avoids the contamination that contaminated soil can produce, but also valorizes this element as a raw material for new materials, avoiding the extraction of clay and reducing the environmental impact.

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