2020

In wall mounted pole structures, the function of anchor bolts is to transfer design forces such as uplift due to wind or vertical gravitational loads to the masonry. KAEG employs advanced engineering best practices to more consistently design and analyse anchors in order to ensure the installation properly embody its requirements.

The method of calculating the pull-out load is based on the shape of the failure surface, a truncated cone, observed during base material failure (Destructive loading). The proof test load is determined through structural analysis of two scenarios; wind perpendicular to wall and wind parallel to wall, taking ancillary orientation into account.

Anchors are tested (Non-destructive loading) with a pass result prior to installation to the calculated proof test load to confirms the holding power of anchors for the purpose of providing assurance of correct installation.

In the event that the calculated pull out load values is high, either load bearing internal back-plates or additional back-plated brackets are installed to strengthen the wall mounted connection, which negates the need to proof test the anchors.

Unlike concrete, masonry walls are not uniform base material and the location of the anchors in the wall affect the performance. Therefore, anchor designs require careful considerations in order to ensure that the applied loads are sufficiently distributed and the masonry is robust.

KAEG are at the forefront of providing valued engineering to achieve cost- and installation effective design solutions in the telecommunication industry to network providers. Contact our expert team at: info@ka-engroup.com to learn more and discuss how we can best serve your needs.

The design of free-standing rooftop structure in accordance with design codes to serviceability criterion is a fundamental first principle design that can be completed by the old-school pen and calculator method, but the solution is often over- or under-designed. The designed solution must be adequate to ensure that the structure is stable against overturning moment (OTM) and sliding forces caused by wind action in addition to eccentric weights, accounting for the ancillaries, steelwork, and ballast frame.

Overturning moments are primarily due to wind forces in addition to eccentric vertical loads about the global centroid of structure. This de-stabilising load must be balanced and counteracted to achieve structural stability and safe operations.  More often, simplified method is adopted that only considers the destabilizing and stabilizing forces on one side of the structure which is not always the optimal design. Configuration optimisation is essential to achieve cost and installation effective solution such as reduced ballast frame size and induced pressure on the roof. This includes:

1. Positioning the antennas and associated RRUs in a staggered configuration to reduce unfavourable eccentricity.
2. Compact configuration which involve shielding the RRUs behind the antennas to reduce the wind destabilsing force.

KAEG are at the forefront of providing valued engineering to achieve cost- and installation effective design solutions in the telecommunication industry to network providers. Contact our expert team at: info@ka-engroup.com to learn more and discuss how we can best serve your needs.

With increasing demand and fast changing technology, there is often a need to install two antennas in each sector to cover a large range of technology. Sometimes, there is enough space to install the antennas on separate primary poles, but often space is limited. For these cases, it is necessary to accommodate both antennas on a single primary pole with desired spacing to avoid clipping. There are two configurations available:

1. Standoff system – One antenna on an offset pole using standoff bracket, and the other antenna on primary pole itself,
2. Yoke system – Both antennae on offset poles using yoke bracket.

A standoff arrangement is often utilised when one antenna is an existing antenna and it belongs to another operator and hence it cannot be moved. However, it is an unfavourable arrangement.  Due to the antenna overhang on one side, the standoff system results in eccentric loading on the primary pole which requires bigger section to support. This also transmits higher bending loads on the primary structure.

A yoke arrangement is preferable as carries two antennae on either side of the primary pole. It can provide the desired spacing between the two antennas to avoid clipping, with less overhang. It also balances the wind load and weight from either side of the bracket and results in lower bending and torsional moments on the yoke bracket and primary pole.

This ultimately results in saving material by reducing the need to have bigger and stronger steel sections.

KAEG are at the forefront of providing cost-effective design solutions to over-stressed telecommunication structures to ensure continuous safe operations. Contact our expert team at: info@ka-engroup.com to learn more and discuss how we can best serve your needs.

Cantilever poles are used throughout the telecommunication industry to support ancillaries such as antennas and dishes. Frequently, the introduction of a proposed ancillary can exceed the capacity of the existing cantilever system, requiring new design requirements, new installations, and consequently, more money. There is a common misconception surrounding how to increase the capacity of a cantilever system.

There are two ways in which cantilever systems are significantly loaded, they can either be shear-dominant or moment-dominant (shown below):

If the system is shear-dominant from the forces presented (i.e. the weight load is greater than the wind load), and the connections consist of two sets of two U-bolts, the bolts will be loaded in shear. For this condition, the greater number of bolts, the more secure the connection. However, in a moment-dominant system, the wind force has a greater effect on the system than the weight load, inducing a moment on the connections. In a moment-dominant system, the distance between the two sets of bolts (or “lever arm”) is the main influence.

If the moment induced on the system is anticipated to exceed the capacity of the existing bolt arrangement, placing a third bolt connection into the system between the existing bolt sets actually reduces the capacity of a moment-holding connection. This is because the lever arm length is reduced in the connection: from the distance between the upper and lower bolt sets, to the upper and central bolt sets.

To conclude, for a shear-dominant cantilever system, a third set of bolts is an appropriate solution. However, for a moment-dominant cantilever system, a better solution is to increase the distance between the existing bolt connections, increasing the capacity of the cantilever system.

KAEG are at the forefront of  providing cost-effective strengthening solutions to over-stressed telecommunication structures to ensure continuous safe operations.

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