Seismic behaviour of prestressed and normal reinforcement of communication tower with ultra-high performance concrete, high strength concrete and normal concrete materials

Nowadays, advances in telecommunications and broadcasting have led to the implementation of communication towers for installing network equipment. These towers are designed to go as high as possible in order to cover large area and avoid obstructions. However, there exist many challenges faced by engineers in relation to design of the tall and slender structures such as the complexity configuration of the structure. The nonlinear dynamic analysis is the only method that describes the actual behaviour of a structure during earthquake. Therefore, this study aims to investigate the behaviour of ultra-high performance concrete (UHPFC), high-strength concrete (HSC) and normal concrete communication tower with 30 m height located in Malaysia under seismic excitation. Also, to provide strength, stiffness and stability for the slender structures due to their sensitivity to dynamic load such as earthquake and vibration forces. For this propose, the finite element model of the tower is developed and time history analysis of communication tower under seismic load was conducted. In addition, the effect of using prestress instead of conventional reinforcement was investigated. The result indicated that prestressing of tower had lesser effect on the lateral displacement of tower under earthquake excitation. Although, the tower with UHPFC and HSC material shows lower lateral peak displacement against earthquake load compared to the normal concrete, which led to the increase in the use of these materials in lateral stiffness of the tower structure

Seismic response sensitivity analysis of intake towers interacting with dam, reservoir and foundation

In this paper, parameter sensitivity analysis of the dynamic response of cylindrical intake towers interacting with the concrete dam, foundation, internal and surrounding water is performed. The tower is modelled and verified using three-dimensional finite elements according to the Eulerian-Lagrangian approach in the time domain. In order to carry out a parametric study, the Taguchi optimization method is employed to distinguish the most influential parameters. Thus, the iteration algorithm and number of numerical tests are designed. The models are tested under longitudinal horizontal excitation of selected reference accelerograms for either hard soil or hard rock. The evaluation of the results indicated that the two parameters, i.e. tower’s slender ratio, and the surrounding water depth are the most effective factors on both intake tower’s top drift and the base shear coefficient under seismic excitations on hard soil. It is observed that the elasticity modulus of the foundation is another influential factor in the seismic response, as the tower’s drift increases with the foundation’s flexibility. Furthermore, the effect of dam interaction on the tower drift reduces as the distance from the dam increases and stays relatively constant for any distance higher than twice the tower’s height. Interesting to note that the intake tower did not show notable sensitivity to the reference hard rock ground motion compared with that of the hard soil ground motion