Robust Power Law Extrapolation for Adhesive Anchors under Sustained Load

Robust Power Law Extrapolation for Adhesive Anchors under Sustained Load

Abstract:

Post-installed adhesive anchors play an important role in modern construction. As with many structural products, adhesive anchors must undergo rigorous testing to verify serviceability and ultimate performance characteristics under job-site-relevant conditions before being used in real projects. The check of long-term performance under sustained load is based on extrapolation from experimental short-term creep data approximating the creep mechanism of the entire anchor system with a power law model as detailed, for example, in ACI 355.4 and ETAG 001. These normative guidelines are critically reviewed from a scientific as well as practical point of view. Based on the presented evidence, specific recommendations for anchor testing and assessment guidelines are proposed.

Keywords: adhesive anchor; creep; extrapolation; long-term performance; post-installed anchors; power law model; sustained load tests

THANKS TO-

Author(s): Roman Wan-Wendner and Jan Podroužek

Publication: Structural Journal

Polymeric Microspheres Provide Resistance to Harsh Winter Conditions

  Polymeric Microspheres Provide Resistance to Harsh Winter Conditions

Title: Polymeric Microspheres Provide Resistance to Harsh Winter Conditions
Author(s): Edward (Ted) G. Moffatt and Michael D.A. Thomas
Publication: Concrete International
Volume: 41
Issue: 1
Appears on pages(s): 36-41
Keywords: air, freezing and thawing, admixture, scaling
Date: 1/1/2019
Abstract:
Issues with providing an optimum air entrainment in concrete can be eliminated using dimensionally stable particles known as microspheres. In this article, performance test data for concretes produced with polymeric microspheres are compared against test data for concrete produced with a conventional air-entraining admixture. While wider use of microspheres in concrete has been hindered by production and logistics costs, the authors believe they could be cost effective for applications that require highly reliable protection against freezing-and-thawing damage.

Retrofitting of Reinforced Concrete Beam-Column Joints by Composites—Part II: Analytical Study

Retrofitting of Reinforced Concrete Beam-Column Joints by Composites—Part II: Analytical Study

Beam-column joints (BCJs) in reinforced concrete (RC) structural systems are the critical regions, especially when they are subjected to high shear demands. According to earthquake reports and joint subassembly tests in the literature, mostly brittle failures were experienced due to inadequate design detailing. To avoid such failures, several strengthening techniques were developed for weak BCJ regions such as externally applied steel and RC jackets, and fiber-reinforced polymer (FRP) materials. Experimental results revealed alleviation of these deficiencies and improved shear capacities of the strengthened joints. Shear capacity predictions of these retrofitted joint subassemblies for design purposes require analytical models. In this study, an analytical model and computation procedure was proposed to predict the lateral load capacities of the shear-critical joint subassemblies with or without carbon fiber-reinforced polymer (CFRP) wrapping technique. Several failure mechanisms such as shear failure in joint panel, crushing of concrete in the beam, yielding of the beam reinforcement, or rupture of CFRP wrapping were determined for each incremental lateral load level and most critical ultimate lateral load capacity was found. The predicted results were compared with the experimental results in Part I of this paper as well as other research in the literature, and they were in good agreement.

Keywords: analytical model; beam-column joints; carbon fiber-reinforced polymers (CFRPs); joint capacity; joint failure mechanisms; reinforced concrete; shear strengthening

 

Retrofitting of Reinforced Concrete Beam-Column Joints by Composites—Part I: Experimental Study

Retrofitting of Reinforced Concrete Beam-Column Joints by Composites—Part I: Experimental Study

Retrofitting of Reinforced Concrete Beam-Column Joints by Composites—Part I: Experimental Study

Author(s): Osman Kaya, Cem Yalçın, Azadeh Parvin, and Selçuk Altay
Publication: Structural Journal
Volume: 116
Issue: 1
Appears on pages(s): 17-29
Keywords: beam-column joints; carbon fiber-reinforced polymers (CFRPs); lap splice; plain reinforcements; reinforced concrete; shear strengthening
Date: 1/1/2019
Abstract:
Many of the existing reinforced concrete (RC) structures in Turkey built prior to 1999 have deficient design details due to their non-seismic design or construction flaws. In particular, the beam-column joints (BCJs) experience high shear forces during such events, mainly due to inadequate design detailing of transverse reinforcements as well as inadequate lap splicing. Severe damage or total collapse of structures often occurred. To enhance the performance of such deficient joint systems, several strengthening techniques such as reinforced concrete and steel jacketing, as well as fiber-reinforced polymer (FRP) wrapping, have been proposed. In this study, new shear strengthening techniques were developed using carbon fiber-reinforced polymer (CFRP) to retrofit these insufficient BCJs. The effectiveness of various CFRP wrapping methodologies was investigated experimentally. One control specimen was constructed according to provisions specified by the 1975 Turkish Building Design Code, whereas four other specimens were constructed with deficiencies observed in the practice. Moreover, three additional specimens were constructed to develop alternative shear strengthening techniques via CFRP wrapping. The quasi-static tests were carried out by applying constant axial load and reversed-cyclic lateral load at the top of the column. Comparative analysis of control and CFRP-strengthened specimens’ results showed that significant improvements in the lateral load and the energy dissipation capacities were achieved by using the proposed CFRP-strengthening techniques.

 

Effect of Piezoelectric Ring Sensor Size on Early-Age Property Monitoring of Self-Consolidating Concrete

Effect of Piezoelectric Ring Sensor Size on Early-Age Property Monitoring of Self-Consolidating Concrete

Title: Effect of Piezoelectric Ring Sensor Size on Early-Age Property Monitoring of Self-Consolidating Concrete
Author(s): Siwar Naji, Kamal H. Khayat, and Mourad Karray
Publication: Materials Journal
Volume: 115
Issue: 6
Appears on pages(s): 813-824
Keywords: nondestructive testing; P-RAT; self-consolidating concrete; setting time; shear wave velocity
Date: 11/1/2018
Abstract:
The objective of this paper is to investigate the effect of the sensor size used in the piezoelectric ring actuator technique (P-RAT) on the accuracy of shear wave (S-wave) measurements that can be used to determine setting characteristics of concrete. Three different P-RAT sensor dimensions operating at different central frequencies of 25, 28, and 45 kHz (big, medium, and small P-RAT, respectively) were investigated. In total, 14 self-consolidating concrete (SCC) mixtures were proportioned with slump-flow values of 600 to 780 mm (23.6 to 30.7 in.). A conventional concrete was also prepared with 220 mm (8.7 in.) slump. The quality of the transmitted signal was found to be higher when using the big P-RAT sensor where less scattering and less energy loss were obtained. This can make it easier to determine the S-wave arrival time, which is needed to calculate the S-wave velocity for concrete with relatively high precision. The setting time of concrete based on the criteria of the S-wave velocity (Vs) derivative is shown to correspond well to values evaluated using the standard penetration resistance test tested on mortar sieved from concrete. The results showed that the big P-RAT sensor is suitable to determine the setting time of concrete by means of the derivative S-wave velocity (in time domain). However, the average setting time of mortar sieved from concrete determined from the standard penetration resistance occurred approximately 60 minutes later compared to the setting time of concrete obtained with the P-RAT approach. This shift can be due to the presence of coarse aggregate that can affect Vs.
Thanks to ACI Journal...

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Pulverized Fuel Ash Cement Activated by Nanographite

Title: Pulverized Fuel Ash Cement Activated by Nanographite
Author(s): Mehmet S. Kirgiz
Publication: Materials Journal
Volume: 115
Issue: 6
Appears on pages(s): 803-812
Keywords: calcium hydroxide content; compressive strength; flexural strength; fluidity; nanographite; pulverized fuel ash cement; water absorption
Date: 11/1/2018
Abstract:
Advancements of early-age physical properties are examined for the pulverized fly ash (pfa) cement system blended with nanographite (nG) in this study. Class F fly ash (FFA), nG, and ASTM Type I cement are used to prepare various cement combinations (for example, 35% FFA + 65% ASTM I + 1.1% nG). Pastes and mortars are mixed with these cements with tap water or with tap water + superplasticizer (SP) to monitor developments on physical properties of the FFA-cement. According to present standards, experimented properties are water absorption, calcium hydroxide content, setting time, flow, flexural strength, and compressive strength for the FFA-cement (FFA-C), FFA-C/nG combinations, pure cement, and PC/nG combinations. It is concluded from the research results that FFA-C activated nG is favorable in terms of water absorption, Ca(OH)2 content, setting time, flow, and strength gain when compared to pure cement and nG-blended cement.

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Top 10 construction technology trends for 2019

The construction industry is under a significant paradigm shift. When we look back throughout this industry’s history we notice some great advancements have taken place. As the end of the year approaches and we look ahead to 2019 there’s no reason we shouldn’t expect more of the same to occur. In fact, here are some of the most noteworthy trends experts believe you should expect to see in the construction industry next year.
Top 10 construction technology #trends for 2019 🏗️Click To Tweet

Augmented reality

Construction World says that although virtual reality has been an emerging trend over the past few years, it’s quickly growing outdated – especially when compared to augmented reality uses and benefits. This is the ability to visualize the real world through a camera lens. It’s something that’s bound to open many new opportunities for the construction industry even though it’ll come with a cost. For those companies who can afford to start using it now, it’ll revolutionize how they project and build things. This is a trend that will grow much bigger in the next few years. In fact, many people believe that instead of using safety goggles, we’ll start planning and plotting sites before we even break ground.

Construction software and data ecosystem

Real-time collaboration software is already regarded as an essential component of the entire building process. Nevertheless, its impact on the sector is expected to increase substantially in the near future. It goes without saying that data has played an integral role in this paradigm shift in construction.
The emergence of a data ecosystem where all the innovative players of the industry will come together and share data, experience and project knowledge is closer than we might think. And it is no exaggeration to maintain that it’s the only way forward for construction.

The ability to integrate your existing processes and systems into a single fully-connected platform can empower the way people in the industry work. A plethora of software solutions for different functions and disciplines in the course of a construction project can now effortlessly be combined in one place.
The use of digital tools facilitates the accumulation of these valuable bits of information and by extension, the minimisation of delays, rework rates, and communication hiccups between the site and the office.
In that sense, a reliable real-time collaboration software is expected to function as the digital backbone for the construction process from start to finish.

BIM will continue growing

Similar to last year, BIM is again one of the hottest construction technology trends. It comes as no surprise if we take into account that the emergence of an open and highly collaborative data ecosystem is on the way.

BIM technology could be the catalyst for a fundamental change in how we manage, design and develop a construction project. There are many different levels of programming enabled through BIM. 4D and 5D BIM are two very representative examples in that direction.

From a general point of view, BIM will bring more accuracy to the building process and empower the exchange of important project information between the numerous stakeholder. Moreover, its further evolution is anticipated to make construction projects more productive and affordable by including revolutionary sustainability and safety measures.
It is evident, then, that BIM could function as a game changer for construction and offer a detailed depiction of the project development in an open and highly collaborative environment.

Increased prefabrication, modularization, and eco-friendliness

There’s been a growing trend towards multi-trade prefabrication. This is something the Multi Trade Prefabrication Conference is now addressing. It was the first ever multi-trade conference that was held for the growing number of construction companies who are implementing prefabrication strategies. A great example of this occurred in Dubai where a 3D office building was printed in 17 days, followed by only two days spent on site assembling it. Many construction industry experts believe we’ll continue seeing this practice grow in the coming years, especially since cost and time are no longer as prohibitive. This doesn’t mean that they’re no longer issues, simply that they’re being addressed in ways that will help propel this industry forward.

Another growing trend is off-site construction (a.k.a. modularization). This trend is similar to prefabrication in that many people see it growing in popularity over the next several years. There are already some progressive construction companies who have started implementing these strategies in the way they run their operations – especially manufacturing companies. These companies use standardized processes to assemble as much as possible off-site before they complete the construction project on site. The benefit here lies in the fact that the standardization cuts down on costs and lead times.

Read also: The European Construction Industry Manifesto for digitalisation – An insight into smarter and cost-efficient sector

All these processes are very beneficial in the following three ways:

• They’re quite eco-friendly because when working on construction in a factory you can easily recycle any extra materials.This is much better than what was happening with traditional construction practices – many of which would often be forced to send large amounts of waste to landfills.
• Prefabrication saves a lot of money because construction companies can get bulk discounts on materials. This also saves them time, which will, in turn, save them even more money.
• Since all the work occurs in a factory-controlled environment there’s less risk for problems that are typically associated with things like moisture, environmental hazards, and dirt. Additionally, construction workers and the project’s eventual tenants are also less likely to be exposed to weather-related health risks.

Self-healing concrete

Many of the industry’s experts believe we’ll start seeing self-healing concrete being used on roads, buildings, and homes. Since concrete is the most widely produced and consumed material in the construction industry (being used to create buildings, roads, and bridges) many believe that by 2030 we’ll be using about 5 billion metric tons per year. Part of this is due to the urban boom that’s being experienced in China and India today. Currently, the United States already makes up 8% of the total global emissions in this area – a number that’s also slated to rise.

Drones

Many construction sites are already heavily dependent on the use of drones. These drones are very beneficial in that they save a lot of time. For instance, surveyors can survey an entire site in just a few minutes, whereas in the past it’d take them several weeks or months. Obviously, this will also save construction companies a lot of money. As drone technology continues rapidly developing in its accuracy and precision of its readings, even less human involvement will be necessary. In the past, many companies were hesitant to use drones because they still needed a controller, but today as the technology grows much more efficient, more construction companies are willingly and openly embracing this technology.

Source: Pbctoday.co.uk

Robotics

JB Knowledge says robotics is something that shouldn’t be overlooked. Industries like healthcare are already investing a lot of money in them. As these robots grow even more precise and accurate, they’ll become a commanding force in the construction industry. In the beginning, the cost of robotics will be high, but it will still be well worth it to at least pay attention to this technology. Eventually, we may witness robots being able to do things like lay bricks and tie rebar, we may even see them complete most of the current man-operated construction projects.

Cloud and mobile technology

Just a few years ago most people either didn’t know or couldn’t explain what a cloud operating system was. Today, this is no longer the case. In fact, most mobile devices can leverage cloud technology from anywhere, at any time. There are many great advantages to this, including storing almost limitless amounts of information that you can then share instantly with the touch of a button. This is much less expensive too – about one-tenth of what sharing old technologies cost. Since the cloud-based business phone system is accessible from anywhere you have an internet connection you can expect it to become a mandatory part of the construction industry in the future, especially if you want to remain competitive.

Advanced uses for GPS

Construction World says while GPS tracking solutions aren’t anything new, they’re now being used in more creative and resourceful ways including:

• Surveying has been dramatically improved because crews no longer need to use traditional surveying equipment.
• Data for prospective project sites can be quickly and accurately collected.
• Project managers are also using GPS in fleet management. Today, each of their vehicles is equipped with a device that is trackable via both computer and smartphones. This lets everyone know where vehicles always are.
• It’s easier to find lost or stolen equipment because managers can now generate maps that pinpoint the exact location of any of these items.

Many people within the construction industry feel that we haven’t even come close to seeing the end of the growth of GPS technology today though. Not only are applications in autonomous vehicles and wearable technology are on the rise, but we’re bound to see driverless vehicles as well. This will no longer be something we only hear about Uber using, construction companies will also be using them too. In fact, the general public will probably have these vehicles available to them as soon as 2020.

Find here: 10 tips for delivering construction projects on time and on budget

They’ll see it in the form of buses, trains, and trucks but construction fleets seriously aren’t far behind. There are many professionals who are currently working on autonomous vehicles that will make job sites even more efficient. For instance, both Caterpillar and John Deere are currently working on dozers that will have automatic blade control and hopefully they’ll take this even further and create fully autonomous and driverless versions of these vehicles as well.
We’re also witnessing the construction industry borrowing from the mining industry. In specific, there’s one piece of driverless equipment that Tokyo–based Komatsu uses GPS in for moving high-grade ore. As the number of these driverless vehicles continues growing, we’ll have a reliable and powerful guide to automated machinery. We’ll also witness GPS tracking solutions be relied on for positioning and sensor integration so that they can avoid accidents and make sure everyone is safer.

New effective scanning solutions

Scanning is now creating many cost-effective solutions over the past few years. These have helped the construction industry fully understand in what stages certain projects are.

Wearable technology

While many people may think this is only common sense, it shouldn’t go unmentioned that wearable technology (e.g. Fitbit’s, 3D glasses, Google Glass, armbands that can communicate with coaches on the sidelines) will become an emerging trend that’s useful in keeping workers safe. This will help keep workers from constantly looking down at their instructions because now they can talk to one another via this technology. Additionally, it can help track where workers are if there’s an accident. This is bound to become mandatory at some point in the future.

Source: Constructionexec.com

Wrapping it up!

Without a doubt, 2019 is expected to be a breakthrough year for the construction industry. A data-driven sector with emphasis on collaboration and real-time communication is hopefully around the corner. Only then, construction stakeholders can hope for higher productivity rates and fewer painful project delays.
THANKS-
Author Bio: Being a senior business associate, Peter Davidson strives to help different brands and startups to make effective business decisions and plan effective business strategies. With years of rich domain expertise, he loves to share his views on the latest technologies and applications through his well-researched content pieces. Follow him on Google+ and Twitter.

 

Top 8 Upcoming Developments and Trends in Civil Engineering 

Top 8 Upcoming Developments and Trends in Civil Engineering for 2018 and Beyond

Civil engineering is poised to undergo major transition in 2018; thanks to the advancement in technology which is the driving force behind the changes this industry will witness. Some of the latest technologies we cover in this write-up which were once dubbed sci-fi have already begun finding a way into the mainstream industry. Since the last decade, the focus remained on smart materials and energy-efficient buildings. But, in recent times, civil engineers are placing more emphasis on computer vision, BIM, virtual reality, sustainability, IoT, and 3D printing technologies that are parallelly gaining prominence. In this write-up, we provide a mash-up of latest developments in civil engineering that are becoming latest trends.

8 Latest Upcoming Trends in Civil Engineering

Here is a compilation of latest trends in civil engineering in 2018 that you should know -

1. Virtual Reality (VR) and Augmented Reality (AR) Will Become Mainstream

   Virtual Reality (VR) and Augmented Reality (AR) are the newest trends in civil engineering to watch out for in 2018. Although the technology itself isn't new, its applicability vis-a-vis civil and construction industry is gaining immense popularity. VR and AR are forms of immersive media to visualize the end results and are increasingly being used by both end users and the civil engineering project teams alike.
   Virtual Reality is empowering the civil engineering industry with a user experience that was once possible only in science fiction! Stakeholders and designers can benefit from the interactive and immersive experience in an isolated ambiance created using sophisticated VR headsets, cardboard viewers, etc. After all, who wouldn't appreciate the virtual experience of stepping into planned constructions even before the implementation?
   Augmented Reality on the other hand interweaves real-world and graphics to give field personnel and civil engineers useful information such as health and safety warnings, productivity statistics, design specifications, etc., making their job on field easy.
   This is just the beginning, and the applications of VR and AR technologies are expected to broaden way beyond expected in 2018 and the years ahead, making them the backbone of numerous civil and construction projects.

2. Building Information Modeling (BIM) Will Be Used in Large-scale Applications

   More civil engineering projects this year are likely to see large-scale utilization of the Cloud technology and Big Data. Also, latest in the list of innovation is the Building Information Modeling (BIM). Engineers can now create virtual models of their designs through intelligent 3D modeling process. This futuristic technology can speed up the time taken to turn building drawings into reality. Construction of bridges, electricity networks, and superstructures can gain momentum with workable virtual models of the designs. As BIM and 3D modeling provide engineers a chance to visualize completed designs at the onset, the design process is poised to be cost-efficient and more streamlined in the future.

3. Demand for Sustainable Designs Will Rise

   Sustainable design is the most significant civil engineering trends in 2018. It is a movement that enjoys much support from global organizations and even the government. The demand for smart materials, intelligent electrical grids, smart buildings with embedded sensors, and other revolutionary technologies is giving civil engineers the push to innovate sustainable designs that are forward-looking. One of the key areas of focus is zero-energy housing. Insulating homes with double skin facade and integrating PV panels that facilitate better utilization of captured energy.
   As space is a major concern with the explosive population growth, smart use of space in housing which can ease the congestion and pave way for sustainable urban development is also a key trend that will find wider acceptance this year and the years ahead.

4. Drones Will Remain a Mainstay

   Drone market has seen a sturdy growth in 2017. The trend is expected to continue even this year and sales of drones is likely to exceed $12 billion by 2021! Commercial use of drones has reached an important milestone with technological enhancements making drones more reliable than before. Drones are steadily making its presence felt in in civil engineering industry, greatly influencing the design, development, and surveying of civil engineering projects.
   Drones are instrumental in carrying out safety inspections along with progress reporting. Drones effortlessly access hazardous sections of the construction and collect data from large areas in a matter of minutes. This technology has allowed surveyors to get the job done without risking life and limb.
   In 2018 and beyond, drones are expected to become part of mainstream civil engineering. However, regulation of drone technology is hotly debated due to its fast-paced evolution and its affordability to the mass market.



5. Advanced Building Materials Will Shape the Civil Engineering Designs of the Future

   Advanced materials with shifting properties that adapt to external conditions are being introduced into the civil engineering industry. From cement composite, advanced steel, and self-healing concrete, to fiber-reinforced polymer composites, technology is transforming the materials being used in construction.
   In 2017, Pavegen, a UK-based technology company outfitted sidewalk in London with innovative technology that harvests kinetic energy from pedestrian movement and turns it into usable energy. This project highlights the need for smart materials to trap and utilize energy which is otherwise wasted. Similarly, 4D-printed structures that transform according to the shifting environmental conditions are the latest fad in civil engineering because they prolong the life of constructions. Buildings in major cities around the world are coated with photocatalytic titanium dioxide to combat pollutants in the air. In the long-term, it will mitigate human-induced environmental hazards. The civil engineering design of the future is all about advanced materials that are largely focused on reducing carbon footprints and harnessing the energy that our planet has to offer.

6. Internet of Things (IoT) Will be Leveraged to Engineer Smart Cities

   Internet of Things (IoT) is a megatrend which is quickly reshaping the way in which civil engineering projects are implemented. In a nutshell, IoT leverages sensors and network connectivity to allow communication between the interconnected sensors. The sheer volume of data being exchanged is collected and analyzed to enhance future decisions. IoT will play a leading role in monitoring the health of urban structures by pooling big data from the building management system. It will be capable of recording data such as variations in concrete humidity, vibrations, chloride content, and even abnormal deformations. The lengthy list of things IoT can achieve is gradually growing thanks to cheap wireless sensors. It is one of the latest upcoming trends that will give rise to smart cities and improve the quality of life of its inhabitants.

7. 3D Printing Is Expected to Have the Most Significant Impact in Civil Engineering

   The year 2017 witnessed a surge in the demand for 3D Printing across various domains. In 2018, this revolution has reached construction and civil engineering industry in a big way. 3D printing can turn engineering designs into scale models or even real components required for building construction. This technology, currently in the advanced stage is ready to take on more complex civil engineering challenges involving full-sized homes and bridges. Scientists are contemplating the use of 3D printing for assisting humanity's efforts to colonize Mars. Without doubt, this is one of the most exciting upcoming trends in civil engineering.

8. Robots May Take Up Mundane Civil Engineering Tasks

   Robots in the construction industry are taking over tasks that are hazardous to humans. It not only improves worker safety and productivity but also saves costs in the long run. Last year, civil engineering industry tasted success with many iterations of bricklaying robots that illustrated efficiency by building walls six times faster than human workers! However, the immediate challenge with Robotics is its initial cost, feasibility of mass application, and reliability. Said that, with continuous improvements in the Robotic technology, we can expect to see robots taking over the mundane tasks in construction and civil engineering in the future.
   

Get Future Ready - Choose O2I to Leverage Top Civil Engineering Trends into Your Business

Outsource2india is a leading engineering service outsourcing company with 19 years of quantitative and qualitative experience in serving clients all over the world. Outsourcing your civil engineering services to us can help you avail numerous benefits that include not just affordable costs and profitable ROI, but also unmatched domain expertise and technological know-how. With deep domain experience and experienced engineers, we can deliver your engineering projects with utmost care and precision straight from our world-class delivery centers or as an extension of your in-house team. At O2I, we also offer diverse civil engineering services such as Terrain Modeling Services, MEP Design & Drafting Services, Paper to CAD Conversion Services, and more that can help you achieve promising results.
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