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Training and Development

FAILURE MODES OF MASONRY WALL SUPPORTING WALL-MOUNTED POLES   

One method commonly employed for the installation of telecommunication ancillaries involves mounting poles directly onto walls at specific elevations, utilising the wall as the primary structural support for bearing the ultimate load reaction from the steelwork. However, the suitability of the wall to support additional loads, such as elevated antennas, raises concerns, particularly regarding concrete and masonry walls. While concrete walls offer greater inherent strength compared to masonry walls, the installation of antennas poses challenges to both types of walls due to potential structural inadequacies.

The wind and weight loads of the telecommunication ancillaries are transferred to the wall in form of tension, shear and sometimes torsion through wall anchors, potentially leading to the masonry wall failure. Shear failure and flexural failure are the two primary modes of failure observed in masonry walls.

  • Shear failure occurs when the shear forces acting on the wall exceed the wall shear capacity, leading to horizontal cracks and potential sliding or tilting of wall segments. This failure can manifest as in-plane or out-of-plane shear, with the latter being more likely in walls supporting elevated antenna poles due to the pull-out force induced by the anchors.
  • Flexural failure is characterised by bending of the wall when the wall’s flexural strength is exceeded. This failure can occur parallel or perpendicular to the wall bed joint depending on the loading direction and wall boundary conditions. The characteristics flexural strength of masonry varies along the plane. The characteristics flexural strength of masonry along the plane perpendicular to the wall bed joint is three times of that parallel to the wall bed joint, highlighting the importance of conducting flexural checks in both planes to ensure structural integrity. Thorough load analysis and adherence to robust design practices are essential for mitigating the risks of shear and flexural failures, thereby enhancing safety and reliability in telecommunication infrastructure installations. Prioritising proactive measures is imperative to meet the demands of modern telecommunication while ensuring long-term resilience and public safety.

At KA Engineering Group, we leverage our extensive engineering experience to consider, advise, and optimise each site, ensuring cost-effective design, installation, and maintenance for build contractors and efficient utilisation for operators. Contact our expert team at: info@ka-engroup.com to learn more and discuss how we can best serve your needs.
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From Cell Towers to Code: Merits of Software Engineers in Telecoms teams

To remain competitive in the changing business landscape, Telecoms structural engineering firms recognise the value of incorporating software engineers into their teams. Here, we explore some advantages of this approach, examining how software engineers can enhance the effectiveness of structural engineering teams.

  1. Automation of repetitious tasks for structural design: In Telecoms, different structure types come with varying number of configurations for their design that trying to keep track with them manually can be strenuous for structural engineers. With software engineers in the team, managing these configurations can be automated with software to aid in increasing the user’s productivity.
  2. Design of bespoke in-house software; technical and non-technical: While the main line of business may be building engineering models, having personnel on hand to build in house applications for tasks like those administrative in nature, or even technical ones like in design results report formatting tools can be advantageous to the firm.
  3. Working on cutting edge future technology to make the business ready to take advantage: Research and development of new technology can be more efficient when structural and software engineers are working in the same team. An example of this is the development of technology that uses LiDAR drones for modelling and analysis of structures. Software engineers working on the project can write programs on reconstruction of 3D models of structures from the drones, while Structural engineers in the team can aid in discarding outliers in generated models through their knowledge of what dimensions a structure of that nature can have realistically.

In summary, this interdisciplinary approach makes it easier to meet growing demands for reliable network infrastructure. At KA Engineering Group, our expert team does not just build precise models of engineering configurations, we partner with our clients in highlighting findings and providing detailed analysis reports. Contact us at: info@ka-engroup.com  to learn more and discuss how we can best serve your needs.
Industry News

Streamlining Telecom Structure Surveys with Lidar Technology

In the realm of telecom infrastructure development, precision and efficiency are paramount. Traditional methods of surveying telecom structures have undergone a revolutionary transformation with the advent of Lidar technology. Lidar, which stands for Light Detection and Ranging, utilises laser beams to measure distances and create detailed 3D models of objects and environments. While previously used primarily in specialised equipment, recent advancements have seen Lidar technology integrated into consumer devices, such as smartphones. Lidar, integrated into smartphones like recent iPhone models, enables capturing precise 3D models of objects.

Gone are the days of cumbersome on-site visits with dedicated cameras or expensive drones. With Lidar-equipped smartphones, surveyors can quickly capture intricate details of structures from a distance. The ability to generate detailed 3D models allows designers to gain a comprehensive understanding of the existing structure, eliminating the need to sift through countless photos, and hoping the surveyor did not miss a crucial angle or having to rely on guesswork.

Lidar technology in smartphones offers a cost-effective and accessible solution for surveying. Surveyors can efficiently capture and analyse data, reducing time and expenses. Portable and versatile, these devices adapt to various environments, from remote cell towers to urban infrastructure.

In conclusion, Lidar technology in smartphones streamlines surveying, enhances accuracy, and provides valuable insights into existing structures. As technology advances, further innovations will revolutionise telecom infrastructure development, making surveying tasks more efficient than ever.
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Failure modes of fasteners in concrete

Failure modes of anchor fasteners refer to the different ways in which fasteners can fail when used in concrete structures. These modes can be categorised as failure of anchor (steel) or the parent material (concrete). These can also be categorized as tension, shear or combined failure, as shown in the attached image.

Here are some common failure modes:

  • Bolt Tensile Failure: This occurs when the tensile strength of the bolt is exceeded, causing it to break or fracture under tension.
  • Concrete Cone Failure: This occurs when the concrete surrounding an anchor fails, typically in a cone shape.
  • Pullout Failure: In this mode, the fastener is pulled out of the concrete due to the tensile forces when the bond between the fastener and the concrete is not strong enough.
  • Concrete Splitting: This occurs when the concrete itself splits or cracks due to the applied forces, causing the fastener to lose its grip or become ineffective.
  • Steel Failure: This occurs when the fastener itself, typically made of steel, fails due to shear stress exceeding its strength. The fastener may fracture or deform, leading to loss of load-carrying capacity.
  • Concrete Pryout: This occurs when the fastener pulls out or displaces the concrete around it. This failure mode is more likely to happen when the fastener is located near the edge of the concrete element.
  • Concrete Breakout: This occurs when the concrete surrounding the fastener fails in shear. It occurs when the applied shear force causes the concrete to crack or break, resulting in the loss of anchorage.
  • Combined Failure: This is a combination of shear and tensile failure. It happens when the bond between the fastener and the concrete is not strong enough to resist the applied shear force, causing the fastener to be pulled out of the concrete.

It is important to consider these failure modes when designing and installing fasteners in concrete structures to ensure their proper performance and safety. At KA Engineering Group, we leverage on our extensive experience to design and recommend most efficient fastening solutions for new as well as existing systems in telecom construction.

Contact our expert team at info@ka-engroup.com to learn more and discuss how we can best serve your needs.
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Why do we need Foundation Strengthening?

The ever-increasing demand for better connectivity means a constant upgrade of the telecommunications network. Put simply, the number of antennas and their sizes are increasing. Practically, this means existing infrastructure, such as towers, needs to support heavier and heavier loads.

In previous blogs, we have touched on tower strengthening to improve capacity. However, what happens when the limiting component is the sub structure (foundation). Take a typical pad foundation for a tower, it was sized for a particular load, cast, and then buried under the ground. What happens when this load capacity is exceeded? Do we just abandon the upgrade?

Can the foundation capacity be increased? The answer to this is a resounding Yes! There are a few ways to increase the stabilization capacity of a pad foundation. The commonest way is through foundation extension, the steps of which we have roughly shown in image attached to this post.

At KA, we have the expertise to design the foundation extension to accommodate your proposed upgrade. We complete stability and bearing checks, dowel calculations and provide reinforcement drawings for the foundation extension. Contact our expert team at: info@ka-engroup.com to learn more and discuss how we can best serve your needs. 
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Elastic Instability – Buckling

For telecommunications structures, members in compression play a significant role in the overall structural behaviour. Such members are often seen in lattice towers, monopoles, tripod and quadpod braces, and ancillary support poles. Therefore, examining buckling, a standard failure mode of such elements, is always pertinent.

Buckling, a major type of instability refers to the sudden loss of stiffness at a critical load, which results in deflection to a side. Such deflections can result in material inelasticity and large deformations, leading to an unstable structure and collapse.

The various structural design codes such as AISC and Eurocodes rely on general ideas from Euler’s buckling formula to calculate strength reduction factors buckling evaluation. Eurocodes, for instance, require the calculation of a non-dimensional slenderness constant, which is then used in established buckling curves for strength reduction factors determination.

 In the event of buckling design failure, we try methods of reducing effective length (mostly by reducing the unbraced length), increasing the sectional area or steel grade and finding ways of reducing load distribution to the concerned member. Since buckling failure can be catastrophic, care must be taken to ensure proper analysis and design are done to prevent avoidable structural failure.

At KA Engineering Group, we leverage our extensive engineering experience to accurately design any form of telecoms structure ranging from complex GDC to basic DD analysis. We take responsible steps to consider, advise, and optimise each site, ensuring cost-effective design, installation, and maintenance for build contractors and efficient utilization for operators. Contact our expert team at: info@ka-engroup.com to learn more and discuss how we can best serve your needs.
Training and Development

Cracked and Uncracked Concrete in Anchor Calculation

The choice of anchor and the method used to calculate its capacity are essential for a successful installation. One critical factor in anchor calculation is the condition of the concrete into which it is installed. Concrete can be either cracked or uncracked, and this distinction significantly impacts anchor performance.

Cracked vs. Uncracked Concrete

Uncracked concrete is where the tensile stress in the concrete is smaller than the tensile strength of the concrete.

Cracked concrete will be seen on reinforced-concrete members under service conditions and in the tension zone.

 Concrete is typically assumed to cracked under normal service load conditions, but when can it be assumed to be uncracked?

Design for uncracked concrete conditions is permitted only when the designer can demonstrate with stress analysis that the concrete around the vicinity of the anchor, will remain uncracked throughout its service life in all future loading conditions. This is typically only the case in members or parts of members which will not experience significant tensile forces.

Conclusion

Distinguishing between designing fasteners for cracked or uncracked concrete is crucial for ensuring the structural integrity and safety of anchors. It is important to follow the codes and standards meticulously when designing and installing these anchors.
Training and Development

Limitations of Structural Models

“All models are wrong, but some are useful”. This aphorism coined by George Box for statistical models may also have a grain of truth about structural models. Often in telecoms structural analysis, assumptions are made to simplify the calculation process or fill in for missing data. A good engineer will ensure that these assumptions are based on sound theory and perhaps even well-established industrial design codes. However, engineers must take care to be aware of the limitations of the any assumptions employed.

As an example, analysis of telecoms structures is based on a static model, that is, checking that the structure survives under the action of an extreme load e.g., a 50-year wind event. Implicit in this design methodology is that fatigue failure is not an issue. Fatigue is the failure of a material under repetitive or cyclic loads at load significantly below loads that would cause yield: think about bending a paper clip back and forth, eventually it will snap.

There are certainly cyclic loads to consider for telecom structures: the wind is not constant; it changes direction and strength. So why do we not perform fatigue analysis for these structures? Well, the steel sizes used for telecoms structures would take a very long time to fail under fatigue for the typical cyclic stresses that they experience so fatigue is not a practical consideration. But is this true for all the components?

Consider a wall mounted antenna fixed to a brick wall by a chemical anchor (these terms should now be familiar to you from our previous blogs 😊). There are several components in that system that can experience rapid fatigue failure. Currently, it may not be practical to conduct fatigue analysis for these components, but this is where it is important that an engineer understands the limitations of the analysis model used.

For these wall anchors, we recommend that site providers and operators have a clearly defined integrity monitoring procedure for inspecting the anchors to ensure that they are still fit for purpose. The consequence of not doing this is that a day will come when you may simply be able to remove the anchor by hand! Even worse still, you may find the EMA on the ground which does not bear contemplating in a busy town centre.

Contact our expert team at: info@ka-engroup.com to learn more and discuss how we can best serve your needs.

 
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Rigger Safety in Telecom Structural Design

A common pitfall in telecoms structural design is to solely consider the proposed structure from the viewpoint of the ancillary (antennas/dishes) operability. This is natural, after all, functioning ancillaries are what make money. However, it is very important to not forget the human element. These ancillaries must be installed/rigged by real people who need to return home safely.

A rigger anchoring to a piece of telecom steelwork effectively puts their lives in the hands of the structural designer. This responsibility should not be taken lightly. Accidental loads in all their various forms must be carefully considered throughout the design phase. Engineers can uphold their ethical responsibility and help to create a safer working environment for employees who construct and maintain these essential telecommunications facilities by prioritising safety during the design phase.

At KAEG, safety is part of our core values, it is a philosophy that underpins everything we do. Our structural teams have real site/ climb experience which allows us to put ourselves in the rigger’s position so we can even sense check “attractive nuisance” steelwork that the rigger is not “supposed” to anchor to.

Stay safe out there and reach out to our expert team at: info@ka-engroup.com to see how we can best serve your needs.
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Drone Surveys: Taking Telecoms Structural Engineering to New Heights

Drone surveying is the use of unmanned aerial vehicles (UAV) equipped with specialized cameras to capture aerial data. It has had a positive impact on the way telecoms structural engineers now approach design, maintenance, and optimisation of telecoms structures from previous traditional methods. Here are some intriguing benefits of this innovation:

  • Seamless Integration with Data Analysis tools: With modern advances in technology and the abundance of data collected during drone surveys, captured images can be transferred to data analysis and modelling tools. Engineers can then create accurate simulations to anticipate the effects of loads on the structural integrity of telecoms infrastructure.
  • Cost-Saving: Drone surveys can reduce manual labour costs and can result in more efficient resource allocation.
  • Virtual Inspections: 3D models can be constructed from sensors like UAV LiDAR sensors, enabling more immersive inspections and minimising safety risk for the engineers on site

In essence, drone surveying is likely to become a quintessential technique for inspecting modern telecoms structures. We are sure the conversation around there use will continue to grow, At KA Engineering Group, we take a responsible approach to considering, advising, and optimizing each site, ensuring cost-effective design, installation, and maintenance for build contractors and efficient utilization for operators. Contact our expert team at: info@ka-engroup.com to learn more and discuss how we can best serve your needs.