Civil Engineering March 2022 | Vol 30 No 2

Civil Engineering March 2022 37 towers is TIA-222 rev H in combination with Eskom standards for condition as- sessment requirements. AIMS AND OBJECTIVES The aim of the project was to analyse the telecommunications towers under the following conditions/criteria: Q Q Condition assessment for any material degradation for maintenance/repair work Q Q Structural analysis for serviceability loading Q Q Structural analysis for ultimate loading (50-year return period). The main objective was to evaluate each tower and generate a maintenance or replacement recommendation. PROJECT PROCESS AND ANALYSIS The process followed for the execution of the project was as follows: Q Q LiDAR scan the tower to generate point clouds Q Q Develop Navisworks models from the point clouds Q Q Generate structural drawings from Navisworks models and the drone imagery Q Q Assess the condition of all structural steel on the tower Q Q Evaluate the foundation condition with recommendations Q Q Analyse the towers in PLS TOWER Q Q Generate maintenance scope of work or replacement motivation. The development of structural drawings without climbing and measuring the steel members was performed by utilising input data from the LiDAR scan which was converted into a Navisworks model from a database of steel profiles. The Navisworks model was utilised in conjunction with the imagery from the drone and the point cloud data to generate structural drawings with dimensions for all the steel sections, and details of all connections on the towers, as shown in Figure 2. The structural drawings were utilised to develop PLS TOWER models for struc- tural analysis purposes. PLS TOWER was selected as the preferred choice for Eskom to be able to maintain a digital database of its network of towers. The condition assessments were considered when modelling the towers and material strength modification fac- tors were incorporated for any structural material loss, as shown in Figure 3. Figure 2 LiDAR point cloud conversion to Navisworks model to structural drawing Point cloud Navisworks model Structural drawing Figure 3 Corrosion on connections Powerful Interface User-defined Beam Creep and Shrinkage Reinforcement Design Polka Engineering Software (Pty) Ltd Cell: (083) 675 5666 Email: coombes@polka.co.za