Safety of 5G Network Physical Infrastructures 181
Concerning design of geotechnical structures, such as foundation elements, reference
is made in Europe to BS EN 1997‐1 [58,59]. In particular, Annex D provides a simple
analytical method for bearing resistance calculation, which can be used for the basis of
calculation.
Finally, with respect to design against seismic events, if simplified analysis methods
that consider the linear elastic response of the structural system, design codes may
allow for a reduction of seismic forces (dividing them by behaviour factors equal to or
larger than one) in order to account for the nonlinear response of the structure. The
values of behaviour factors strongly depend on the structural system configuration,
elastoplastic behaviour and robustness.
8.3.4.2 Serviceability Limit States
The serviceability limit states (SLS) verifications are usually specified in the form of
deflections and rotations limits, as well as vibrations and stress limits. Regarding load
combinations, the same guidance as for ULS is used, although the loads involved can
differ in order to take into account specific operating conditions.
Under the most adverse load combination, it is often considered the SLS to be expressed
by a maximum lateral displacement at the top of the structure in the along wind direction equal to h/50 (where h represents the height of the structure). In the crosswind
direction, for the RC2 class, the maximum lateral displacement at the top of the structure
should not exceed 10% of the diameter that encloses the top section of the tower.
8.4 Survey of Problems
8.4.1 General
There are still large uncertainty levels and many complexities involved in the development of strategic plans for the future of communication structures. Service disruptions
caused by physical destruction tend to be more severe and last longer than those caused
by disconnection or congestion, because of the time and funding needed to repair and/or
replace the structure. Historically, communication networks have been highly vulnerable
to physical destruction. Seen as the most sophisticated and fragile urban infrastructure,
communications networks are damaged in nearly every major urban disaster.
In the recent years, performance‐based design philosophy has been gradually introduced in design standards, but little has been made towards resilience‐based design. For
example, for certain design scenarios, key physical infrastructures are required to withstand the event but do not need to remain functional. However, it is when such events
occur that communication services increase as civil protection and emergency services
intervene, people try to contact and connect with their families and remote access
requests to businesses expand. In these situations, systems already severely strained are
pushed beyond their operational limits. For example, in the 1995 earthquake that struck
Kobe, Japan, communications failures prevented outsiders from receiving timely information about the severity of damage. These communications breakdowns delayed relief
efforts for days, stranding tens of thousands of homeless victims outdoors in freezing
winter weather. In a near future, such failures could result in unexpected events without
precedents.
Concerning design of geotechnical structures, such as foundation elements, reference
is made in Europe to BS EN 1997‐1 [58,59]. In particular, Annex D provides a simple
analytical method for bearing resistance calculation, which can be used for the basis of
calculation.
Finally, with respect to design against seismic events, if simplified analysis methods
that consider the linear elastic response of the structural system, design codes may
allow for a reduction of seismic forces (dividing them by behaviour factors equal to or
larger than one) in order to account for the nonlinear response of the structure. The
values of behaviour factors strongly depend on the structural system configuration,
elastoplastic behaviour and robustness.
8.3.4.2 Serviceability Limit States
The serviceability limit states (SLS) verifications are usually specified in the form of
deflections and rotations limits, as well as vibrations and stress limits. Regarding load
combinations, the same guidance as for ULS is used, although the loads involved can
differ in order to take into account specific operating conditions.
Under the most adverse load combination, it is often considered the SLS to be expressed
by a maximum lateral displacement at the top of the structure in the along wind direction equal to h/50 (where h represents the height of the structure). In the crosswind
direction, for the RC2 class, the maximum lateral displacement at the top of the structure
should not exceed 10% of the diameter that encloses the top section of the tower.
8.4 Survey of Problems
8.4.1 General
There are still large uncertainty levels and many complexities involved in the development of strategic plans for the future of communication structures. Service disruptions
caused by physical destruction tend to be more severe and last longer than those caused
by disconnection or congestion, because of the time and funding needed to repair and/or
replace the structure. Historically, communication networks have been highly vulnerable
to physical destruction. Seen as the most sophisticated and fragile urban infrastructure,
communications networks are damaged in nearly every major urban disaster.
In the recent years, performance‐based design philosophy has been gradually introduced in design standards, but little has been made towards resilience‐based design. For
example, for certain design scenarios, key physical infrastructures are required to withstand the event but do not need to remain functional. However, it is when such events
occur that communication services increase as civil protection and emergency services
intervene, people try to contact and connect with their families and remote access
requests to businesses expand. In these situations, systems already severely strained are
pushed beyond their operational limits. For example, in the 1995 earthquake that struck
Kobe, Japan, communications failures prevented outsiders from receiving timely information about the severity of damage. These communications breakdowns delayed relief
efforts for days, stranding tens of thousands of homeless victims outdoors in freezing
winter weather. In a near future, such failures could result in unexpected events without
precedents.