Zipline calculations — Profile and cable verification

Vertic’Alps Engineering carries out zipline profile studies and cable calculations, for a new installation or a modification to existing equipment.

Our aim is to define a configuration suited to the terrain, users and intended operating conditions: departure and arrival locations, cable properties, installation tension and required clearances.

The study is based on the current assessment references relevant to the project, including:

• The Eurocodes.
• NF EN 15567-1, where the installation falls within its scope.
• The STRMTG technical guide RM2 — General design and substantial modification of cable cars, for the arrangements selected for the project.

The references, versions used and calculation assumptions are specified in the structural calculation report. The study also takes account of the properties and requirements of the equipment manufacturers.

Within the agreed scope, our study includes:

• Examining the longitudinal profile: departure and arrival locations, anchor elevations, terrain and obstacles beneath the trajectory.
• Identifying a suitable configuration: cable properties, anchor heights and installation tension.
• Calculating the cable profile: unloaded and loaded configurations, sag and clearances above the ground and obstacles.
• Verifying cable strength: calculated loads, mechanical properties and allowance for terminations in accordance with applicable requirements.
• Determining the loads transferred to the supports: load magnitudes and directions for the configurations studied.
• Speed-calculation scenarios: comparison of zipline behaviour for different user masses and profiles, equipment and selected wind conditions. We examine in particular how headwinds and tailwinds affect speeds along the route and on approach to the arrival point.
• Examining arrival conditions: consideration of the proposed braking system, its properties and its manufacturer's requirements.

The results enable comparison of the configurations studied and clarification of the installation and operating parameters to adopt.

Loads transferred to the anchors are also input data for the structural design of supports and foundations.

The simulations address the configurations and assumptions defined with the client. They provide information for examining technical choices; on their own, they do not constitute overall approval of the selected gradient, braking system or operating conditions.

Depending on the assignment, we provide:

• A structural calculation report in PDF format, presenting input data, assumptions, configurations studied and results.
• A longitudinal profile, showing the ground, anchor points and cable configurations studied.
• A schedule of loads transferred to the supports.
• The selected installation and operating parameters, with their conditions of validity.

To carry out the study, we request in particular:

• The layout drawing and proposed departure and arrival positions.
• The topographical site data, including obstacles and clearance constraints.
• Available anchor-point heights and constraints concerning supports.
• The properties of the proposed cable: construction, diameter, mass per unit length, elongation properties and minimum breaking load.
• A description of the proposed terminations and tensioning devices.
• The properties of equipment used to carry and suspend users.
• The properties and instructions for the proposed braking system.
• Proposed operating conditions: user-mass range, individual or multiple use, and specific restrictions.
• For an existing installation, the available drawings, calculations and assembly details.

Missing data and outstanding choices are identified at the start of the assignment.

The study scope, configurations to examine and deliverables are defined before calculations begin.

The necessary geometric and technical data must be sufficiently accurate to represent the installation. Any additional survey work is specified in the assignment.

The results correspond to the assumptions and configurations described in the structural calculation report. Changing the cable, anchors, equipment or operating conditions requires an assessment of the effect on the study.