Collapse Of Tower Research Articles

Novel approach to detect encasement failures in the anchorage system of guyed transmission towers by distribution of relaxation times

Anchor rods of guyed transmission towers encapsulated in Portland cement pastes and mortar are usually affected by corrosion processes when buried in soils with chemical aggressiveness. Encasement failures, such as cracks and leaks, cause preferential points of degradation of the inner metal bar, affecting its mechanical integrity over the years and causing, in many cases, the collapse of the transmission tower. However, the nondestructive testing (NDT) used for diagnosis has not shown conclusive results. In this study, a methodology to detect failures in the cement paste encasement was developed using electrochemical impedance spectroscopy (EIS) by evaluating the distribution of relaxation time constants (DRT) to identify different time constants of water in the pore structure of cement paste. These parameters were typically determined by the nuclear magnetic resonance (NMR) relaxometry technique, which was not correctly applied to the field tests. From the results, it was possible to detect the presence of cement paste in soils with electrical resistivities varying from 4.0 to 200.0 Ω.m by identifying their time constant at 0.10 ms, which was attributed to the water present in the hydrated calcium silicate gel (C-S-H) interlayers.

The behaviour of orthodox historic churches built with lime mortar in Romania consolidated with reinforced concrete after the 1977 earthquake

In Romania, historic monuments have suffered significant damage after earthquakes. In the southern part of Romania, in the Oltenia region between the years 1838 and 1977, five strong earthquakes with magnitude exceeding 7 ML occurred, causing severe and repeated damage to Orthodox churches constructed with brick masonry and lime mortar. After the 1940 earthquake, consolidation was carried out with modern materials for that period, such as metal ties and reinforced concrete. Due to the collapse of the central tower made of brick masonry during the 1977 earthquake in the Church of the Holy Archangels Michael and Gabriel in Craiova, it was reconstructed using reinforced concrete columns and beams. Furthermore, the consolidation was carried out using reinforced concrete. Due to the different mechanical properties of historic brick masonry with lime mortar and reinforced concrete, cracks appeared over time on the church walls in the contact zones between these materials. Under the coordination of Bishop Irineu of Oltenia, consolidation works were initiated for 17 historic monument churches in the Gorj region after the earthquakes in 2023, and this Church in Craiova was included in the list. The article presents the modes and areas of damage resulting from the introduction of consolidations with irreversible materials, together with the results of in situ tests conducted by the EXPIN laboratory in Padua, Italy, to determine the mechanical properties of the load-bearing elements comprising the Church and structural analysis of the Church using ETABS software to predict past, present, and future behaviour.

Failure mechanism of a Q690 steel tubular transmission Tower: Full-Scale experiment and numerical simulation

The failure mechanism of a Q690 steel tubular transmission tower is investigated through full-scale experiment. The tower is mainly subject to the influence of the wind and the loads from the transmission lines. The displacements and the strains of the key positions as well as the ultimate bearing capacity of the tower are thus obtained. The final collapse is induced by the buckling instability of the compressed main member of a tower leg. A finite element model is established, whose validity is verified by the experimental data. Then, the numerical model is used for further analysis on the structural responses of the tower. It is found that once plasticity occurs at a certain point on the main member, its lateral displacement would be much accelerated, thus amplifying the second-order effect thereof. The horizontal auxiliary members, connected to the bottom of the compressed main member, are initially under tension. While the deformation of the main member is aggravated, they gradually undergo the transition from tension to compression, constituting a lateral support to the main member. This support then enforces the plasticity to develop towards the middle section of the main member, resulting in the final failure at the same location as observed in the full-scale experiment. These findings are crucial for a progressive understanding of the failure mechanism of this type of high-strength steel tubular towers, and they have contributed to the optimization of the design method to prevent the collapse of transmission tower under similar circumstances.

Progressive failure and seismic fragility analysis for transmission towers considering buckling effect

Transmission towers are essential components supporting the operation of the power grid. Accurately predicting their ultimate bearing capacity and progressive failure improve the performance design of electrical power systems. This paper proposes a progressive failure method for transmission towers considering the buckling and post-buckling behaviors of steel angles. To simulate the nonlinear hysteretic behaviors of steel angles, a phenomenological hysteretic model (PHM) is introduced and embed into the ABAQUS software by calling a user-defined subroutine VUMAT. The accuracy and reliability of the PHM are verified through a full-scale test of a transmission tower. The comparison results demonstrate that the PHM can accurately reproduce the displacement and strain responses of the transmission tower and the ultimate bearing capacity, with a maximum error of <15%. The buckling failure of leg members is the main factor for the collapse of the transmission tower. The study also investigates the progressive failure process of the transmission tower under strong earthquakes and estimates the collapse fragility and seismic losses. The results reveal that early failures of steel angles may alter the local force transmission path of the tower and eventually lead to its collapse. This research provides suggestions for the structural optimization and design decision-making of transmission towers.

Monitoring Pergeseran Tanah Tapak Tower Transmisi PT (PLN) Persero Dengan Menggunakan SMS Sebagai Notifikasi Peringatan

Landslides are one of the causes of the collapse of the transmission tower of PT PLN (Persero) which caused power outages, therefore monitoring the shifting of the transmission tower tread is very necessary so that power outages due to the collapsed tower can be anticipated faster. In this study the authors made a study to monitor tower shifts by using Ultrasonic sensors and LVDT sensors (Linear Variable Differential Transducer), Ultrasonic sensors function to detect shifts from towers and LVDT sensors function to detect shifts from the left and right tread tower ground. In this research, there are three main sensors, namely 2 LVDT sensors and one Ultasonic sensor - each sensor is placed in a safe position from interference and has the least possibility of being affected by landslides, Ultrasonic sensors read the tower shift towards the sensor mounted on the center side and LVDT sensors read the shift ground tread tower on the left and right side of the tower. The sensor sends the signal then is converted by the ATMega 8535 microcontroller into a millimeter unit for LVDT sensors and centimeter meter for Ultrasonic sensors. To find out the changes that occur in the tower and tower ground. Every change in distance or the occurrence of a microcontroller shift sends event data in the form of tower numbers and tower shift distances from each sensor reading using SMS (Short Message Service) communication. The installed LVDT sensor has a reading accuracy rate of 98,05% for LVDT 1 and 98,98% for LVDT 2 in millimeters and an Ultrasonic sensor has a reading accuracy rate of 99,44% in centimeters.

Fragility Analysis of Wind-Induced Collapse of a Transmission Tower Considering Corrosion

To investigate the variation law of the wind-resistant performance of transmission towers during their operation, this paper proposes an evaluation method for the wind resistance of the transmission tower considering corrosion, and a 220-kV transmission tower is analyzed as an example. Considering the uncertainty of the material and geometric parameters, the wind-induced collapse of the transmission tower was analyzed, and the collapse wind speeds were obtained via pushover and incremental dynamic analyses. In addition, the sensitivity of the transmission tower to various parameters was analyzed. Based on the existing meteorological and corrosion data, corrosion prediction models were established using a back-propagation (BP) artificial neural network, and the mean relative error between the predicted and measured values of the test samples was 8.91%. On this basis, the corrosion depth of the tower members in the four regions was predicted, and the fragility of the transmission tower was analyzed considering the effects of corrosion and strong winds. The results show that the collapse wind speed of the transmission tower is most significantly affected by the thickness of the angle steel, followed by the elastic modulus and yield strength, and is less affected by the width of the angle steel. When the exposure time was 25 years, the wind-resistant performance of transmission towers in regions with severe acid rain and coastal industrial regions decreased by 10% to 20%. With an increase in exposure time, the failure mode of the transmission tower tended to be brittle failure.

IMPACT OF THE EXISTENCE OF THE BTS TOWER (BASE TRANSCEIVER STATION) IN JATIROTO DISTRICT, WONOGIRI REGENCY YEAR 2021

Noviasari, Anggi. NIM. 1751100010. Impact of the Existence of BTS Tower (Base Transceiver Station) in Jatiroto District, Wonogiri Regency in 2021. Supervisor : Muh Husyain Rifai,S.Pd,M.Pd. and Ary Wijayanti, S.Pd, M.Pd. Essay. Geography Education Study Program, Faculty of Teacher Training and Education, University of Veterans Bangun Nusantara, Sukoharjo. 2021. This study aims to determine: (1) the distribution and affordability of the BTS tower signal (2) The impact of the existence of the BTS tower on the education of students at SMKN 1 Jatiroto (3) The impact of the existence of the BTS tower on the economic changes of the community around the BTS tower. The method used in this study is a qualitative descriptive method. This study describes/describes and finds out the impact of the existence of BTS towers on the education of students of SMKN 1 Jatiroto and the economic changes of the surrounding community. Data collection techniques used are through observation, questionnaires and documentation. The results of the study can be concluded that: (1) The distribution and coverage of the BTS Tower Tower signal in Jatiroto District is spread over three areas and there are five BTS Tower Towers. Each BTS Tower can reach a signal as far as 5km and this is also influenced by the topography of the surrounding area (2) The impact of the existence of a BTS tower on the education of students at SMKN 1 Jatiroto has a positive impact in the form of making it easier for students to access the internet, making it easier for students to learn. The negative impact is radiation from the BTS tower signal and anxiety about the collapse of the BTS tower. (3) The impact of the existence of the BTS Tower on the economic changes of the surrounding community is that it can increase economic income, such as increasing income for people who sell credit and make it easier to access the internet. The negative impact is the increasing number of people's needs to buy credit which results in an increase in public spending, radiation from BTS tower signals.

On the collapse of the masonry Medici tower: An integrated discrete-analytical approach

Masonry towers are characterized by a high susceptibility to seismic actions. For this task different approaches exist and they are selected depending on the desired level of accuracy of the analysis. The identification of the correct collapse configuration is however complex and necessitates thorough on-site surveys. Construction codes usually require the study of local and global collapse mechanisms based on simplified kinematic analysis. More elaborated approaches such as nonlinear finite element methods have been used to simulate the response of masonry towers. Although successful in many applications, these methods are limited in accurately capturing crack distributions and fracture mechanisms. In this work, an integrated discrete-analytical approach is proposed. First, the Lattice Discrete Particle Model (LDPM), which simulates masonry at the stone level and has a superior capability in capturing fracturing processes, is adopted to simulate masonry towers subjected to seismic excitation. The numerical model is used to predict the actual collapse mechanism. Next, the final fractured configuration is used in the kinematic analysis for the calculation of the ultimate condition. The proposed method is used to analyze the collapse of the Medici tower that collapsed during the 2009 L’Aquila earthquake. The simulations are able to predict the induced damage and the crack contours, which are used then to identify six different failure configurations. The subsequent kinematic analyses take into account the relative position of openings and fracture locations. The results show that the collapse of the Medici tower is well replicated by LDPM and the corresponding kinematic analyses demonstrate the efficiency of the proposed hybrid approach applied to this case study. The paper also points out that different load configurations, more specifically the direction of the seismic action, result in certain cases in more diffused damage and a clear failure pattern cannot be identified for kinematic analyses. In these cases, it appears fundamental to rely mainly on comprehensive numerical models, such as LDPM, to study the fracturing process from the cracks trigger to the ultimate complex collapse mechanism.

Effect of Cross-Section Dimension on the Safety of Transmission Tower

The safety of power transmission tower directly affects the supply of electricity. If the designed power transmission tower could not bear the strong wind, the collapse of transmission tower would lead to the power outage. In this paper, we analyzed the safety of transmission tower subjected to the strong wind of level 10 by using a finite element method. Commercial software Abaqus was used for simulating the mechanical response of transmission tower. Finite element model was introduced to complete the static analysis of truss structure. Ten kinds of cross-sections were chosen to assess the safety of transmission tower. According to the simulated results, both the maximum stress and the maximum displacement decrease with the increasing cross-section dimension. When the cross-section dimension is less than a certain value, the designed power transmission tower could not safe under the strong wind of level 10.

Finite element model of bolt looseness of wind turbine tower

Flange bolt looseness is one of the common problems of wind turbine tower, and is the main factor leading to the collapse of wind turbine tower. In this paper, based on ANSYS Based on the finite element analysis method of workbench, the local finite element vibration analysis model of tower drum is established and verified by experiments. Based on this model, the influence of bolt looseness number, wind strength and wind direction on the phase difference between the upper and lower flange plates is studied. The results show that the flange plate with certain bolt looseness ratio is at the top and bottom. The absolute value of the phase difference between the plates is obviously larger than that when the bolts are tightened. Therefore, the phase difference between the upper and lower flanges can be used as the basis for judging the looseness of the bolts in the tower flange.

Performance assessment and collapse prediction of a latticed tension-type transmission tower

This paper aims to provide a comprehensive performance assessment of a latticed tension-type transmission tower by performing both full-scale static tests and numerical simulations. In particular, a full-scale tension-type transmission tower was firstly constructed and tested for examining the performances under design loads and the ultimate capacity under an extreme wind load. The displacement and strain responses are investigated, and the failure process of the tension-type tower is presented. Numerical simulations are then performed in order to capture the failure process and estimate the bearing capacity of the experimental tower under the overload case. Moreover, Numerical simulations are also adopted to evaluate the influence of wind attack angles on the structural behavior of the tested tower. Experimental and numerical results demonstrate that this latticed tension-type transmission tower is designed with sufficient capacity to resist the design loads, and the buckling failures of the leg members at the bottom are the governing reason for the collapse of tower. In addition, the developed numerical model can accurately present the failure and structural response of the tension-type tower, and the influence of wind attack angles on the structural behavior is significant. This research is beneficial for improving the understanding on the bearing capacity and design of latticed tension-type transmission towers.

Numerical analysis of the dynamic effects of wine-cup shape power transmission tower-line system under ice-shedding

This study aims at the dynamic response analysis and collapse simulation of wine-cup shape power transmission tower-line system under ice-shedding. A finite element model for wine-cup shape power transmission tower-line system is developed. The modeling techniques are discussed in detail. The static response under ice-accretion and dynamic response under ice-shedding of the system are both analyzed. A progressive collapse analysis of the tower-line system is also conducted. The numerical results show that the ice accretion on power transmission line mainly affects the cross arm of the tower, rather than the power transmission lines or the tower body. Middle shedding and uniform shedding are the most detrimental ice-shedding modes while end shedding has little influence on a single line. For tower-line system, asymmetric ice-shedding and the ice-shedding on two lines at the same span have more influence on the system than the ice-shedding on one line at a single span and at two continuous spans. The comparison between the numerical results and calculated results shows that the dynamic response of the power transmission line would be intensified under the influence of the tower and multi-span ice-shedding. The calculated results by using the proposed simplified formula considering the dynamic effect of tower-line system show good agreement with the simulation results. The middle V-part is the most crucial part in the standard wine-cup shape power transmission tower. This study suggests that special attention should be paid on the structural members connecting the middle V-part and other parts of the tower, whose fracture would easily trigger the collapse of the whole tower.

Full-scale test and numerical failure analysis of a latticed steel tubular transmission tower

Ultimate capacity evaluation is of vital importance for electricity transmission tower-line systems, which are well recognized as the lifeline engineering in modern society. Undoubtedly, full-scale tests are the most effective and straightforward method for an in-depth understanding of the structural ultimate capacity. In the present study, full-scale tests of a latticed steel tubular transmission tower are performed with emphasis on the failure mechanism of the tower under extreme wind load. Structural responses, ultimate capacity and failure mechanism of the transmission tower in the tests are presented and discussed, respectively. Numerical simulations are then carried out to reproduce the failure of the transmission tower in the tests. In the finite element (FE) model, a buckling and softening failure model is developed to capture the behaviors of the transmission tower. Finally, numerical results are investigated and compared with those obtained in the full-scale tests. Experimental and numerical results demonstrate that the latticed steel tubular transmission tower is designed with enough capacity to resist the designed loads, and the buckling failures of leg members are the dominant cause of the collapse of the transmission tower. Additionally, the developed buckling and softening failure model can accurately reproduce the displacements, ultimate capacity and failure mechanism of the transmission tower. This research can extend the current state of knowledge concerning full-scale tests of latticed transmission towers, and provide a more comprehensive understanding of the performance of latticed steel tubular transmission towers under extreme loads.

Wind Turbine Tower Failure Modes under Seismic and Wind Loads

This paper studies the structural responses and failure modes of a 1.5-MW horizontal-axis wind turbine under strong ground motions and wind loading. Ground motions were selected and scaled to match the two design response spectra given by the seismic code, and wind loads were generated considering tropical cyclone scenarios. Nonlinear dynamic time-history analyses were conducted and structural performances under wind loads as well as short- and long-period ground motions compared. The results show that under strong wind loads the collapse of the wind turbine tower is driven by the formation of a plastic hinge at the lower section of the tower. This area is also critical when the tower is subject to most ground motions. However, some short-period earthquakes trigger the collapse of the middle and upper parts of the tower due to the increased contribution of high-order vibration modes. Although long-period ground motions tend to result in greater structural responses, short-period earthquakes may cause brittle failure modes in which the full plastic hinge develops quickly in regions of the tower with only a moderate energy dissipation capacity. Based on these results, recommendations for future turbine designs are proposed.

Wind-induced collapse analysis of long-span transmission tower–line system considering the member buckling effect

The collapse problem of transmission tower upon strong winds was well noted in past few years. This article analyses the wind-induced collapse problem of a long-span transmission tower–line system. The member buckling effect was particularly considered. In doing so, a three-dimensional finite element model of the long-span transmission tower–line system was established in ABAQUS based on a practical project. The transmission tower and line were simulated by the frame and truss elements, respectively. The nonlinear behavior of a compressive member was simulated using the Marshall model, and the nonconvergence of numerical calculation was set to be the collapse criterion. The critical wind speed, damage position, and collapse probability were obtained from a collapse analysis of the long-span transmission tower–line system under different wind attack angles. The collapse mechanism of the long-span transmission tower–line system under a wind attack angle of 45° was investigated, and an incremental dynamic analysis was performed to evaluate the collapse-resistant capacity of the transmission tower. The study reveals that the interaction between bending moment and shear deformation is critical to the collapse of transmission tower.

Collapse Analysis of Transmission Tower Subjected to Earthquake Ground Motion

The collapse of transmission towers involves a series of complex problems, including geometric nonlinearity, material nonlinearity, dynamic nonlinearity, and the failure of members. Simulation of the process of collapse is difficult using traditional finite element method (FEM), which is generated from continuum and variation principle, whereas the finite particle method (FPM) enforces equilibrium on each point. Particles are free to separate from one another, which is advantageous in the simulation of the structural collapse. This paper employs the finite particle method (FPM) to simulate the collapse of a transmission steel tower under earthquake ground motions; the three-dimensional (3D) finite particle model using MATLAB and the 3D finite element model using ANSYS of the transmission steel tower are established, respectively. And the static and elastic seismic response analyses indicate that the results of the FPM agree well with those of the FEM. To simulate the collapse of the transmission steel tower, a failure criterion based on the ideal elastic-plastic model and a failure mode are proposed. Finally, the collapse simulation of the transmission steel towers subjected to unidirectional earthquake ground motion and the collapse seismic fragility analysis can be successfully carried out using the finite particle method. The result indicates that the transmission steel tower has better seismic safety performance and anticollapse ability.

Degeneracy breakdown as a source of supernovae Ia

In a confined system of multiple Fermions, the particles are forced into high energy levels by the Pauli Exclusion Principle. We refer to this system as a Pauli tower. We pursue the investigation of a model for sub-Chandrasekhar supernovae Ia explosions (SNIa) in which the energy stored in the Pauli tower is released to trigger a nuclear deflagration. The simplest physical model for such a degeneracy breakdown and collapse of the Pauli tower is a phase transition to an exactly supersymmetric state in which the scalar partners of protons, neutrons, and leptons become degenerate with the familiar fermions of our world as in the supersymmetric standard model with susy breaking parameters relaxed to zero. We focus on the ability of the susy phase transition model to fit the total SNIa rate as well as the delay time distribution of SNIa after the birth of a progenitor white dwarf. We also study the ejected mass distribution and its correlation with delay time. Finally, we discuss the expected SNIa remnant in the form of a black hole of roughly Jupiter mass and the prospects for detecting such remnants.

Metallurgical analysis of the collapse of a telecommunication tower: Service life versus capital costs tradeoffs

Abstract Introduction Despite knowledge and expertise nowadays, minimizing capital costs may continue to be the remote cause of failure of many engineering structures. Failure analysis of a telecommunication tower, which collapsed during a thunderstorm recently in a public institution, was carried out in this work. Method The service history was obtained, and the design, fabrication and the material selection were scrutinized along with standard specification for such structure and microstructural examinations were done. Results and discussion The material choice, joint design and weld fabrication allowed differential aeration cells and heat affected zone stress induced corrosion at the welded endplate joints on the structural members. External painting was of no use because while the structure was intact outside, the pipe had the option of corroding from inside due to differential aeration cells. Galvanizing also is sacrificial and consumed interior coating cannot be replaced in-situ. As materials degraded, stresses concentrated. Under wind current, the structure gave up where stress concentrated most. The tower came down after nine years of service, crushing nearby roof and walls. Comparison shows costs factor weighted heavily in the material selection and design, trading off service life. Conclusion Remote cause of failure - cost minimization. This reality features in many designs in today's world of ever tighter capital budgets. It appears an index of service life trade-offs for costs is now needed in designs.

Analysis of the seismic collapse of a high-rise power transmission tower structure

In this paper, an explicit dynamic analysis method is proposed to calculate the progressive collapse of a high-rise power transmission tower structure subjected to earthquake; the failure rule for member elements and the effect of different ground motion inputs and tower heights on the tower's collapse pattern in an earthquake are investigated. The study results show that explicit dynamic analysis can be easily applied to member fractures and that this method is suitable for calculating the seismic collapse of a power transmission tower. The selection of the member element failure rule has a significant impact on the forecast collapse pattern of a power transmission tower in an earthquake. The compression member buckling and softening failure rule, coupling the material nonlinearity with elastic buckling phenomenon, can stave off the effort in modeling the constructional eccentricities, which result in Euler buckling. For different earthquake waves, the high-rise power transmission tower demonstrates different collapse failure modes. The static collapse pattern from a pushover analysis and the dynamic collapse pattern are very different. The actual collapse pattern of a power transmission tower during the Wenchuan earthquake and the computer simulated collapse pattern are compared to validate the algorithm proposed in this paper. Finally, the seismic collapse vulnerability of a high-rise power transmission tower is evaluated based on probability estimate method.

Mitigation of Ground Vibration due to Collapse of a Large-Scale Cooling Tower with Novel Application of Materials as Cushions

Ground vibration induced by the collapse of large-scale cooling towers in nuclear power plants (NPPs) has recently been realized as a potential secondary disaster to adjacent nuclear-related facilities with demands for vibration mitigation. The previous concept to design cooling towers and nuclear-related facilities operating in a containment as isolated components in NPPs is inappropriate in a limited site which is the cases for inland NPPs in China. This paper presents a numerical study on the mitigation of ground vibration in a “cooling tower-soil-containment” system via a novel application of two materials acting as cushions underneath cooling towers, that is, foamed concrete and a “tube assembly.” Comprehensive “cooling tower-cushion-soil” models were built with reasonable cushion material models. Computational cases were performed to demonstrate the effect of vibration mitigation using seven earthquake waves. Results found that collapse-induced ground vibrations at a point with a distance of 300 m were reduced in average by 91%, 79%, and 92% in radial, tangential, and vertical directions when foamed concrete was used, and the vibrations at the same point were reduced by 53%, 32%, and 59% when the “tube assembly” was applied, respectively. Therefore, remarkable vibration mitigation was achieved in both cases to enhance the resilience of the “cooling tower-soil-containment” system against the secondary disaster.