Construction Of Tower Research Articles

Gate-to-gate life cycle analysis of a pilot-scale solar driven two-step thermochemical hydrogen sulfide decomposition for hydrogen production

Hydrogen is one of the most viable options towards decarbonization. It is crucial to upscale the hydrogen economy considering the current state of the environment due to the adverse effects of climate change. In this study, a gate-to-gate Life cycle assessment (LCA) was conducted on a hydrogen sulfide splitting model that replicates a pilot-scale plant by integrating the two-step solar thermochemical H2S decomposition using SimaPro version 9.4.0 software. This analysis starts from the treatment of H2S gas released by the refineries as waste and ends at the production and storage stage of hydrogen. There are two functional units used in this study which are ‘1 kg of H2’ to assess the operational phase of the simulation plant and ‘1 unit of H2S splitting plant’ to determine the environmental performance of the construction of the plant. The top three most impacted midpoint level categories in the operational phase are human carcinogenic toxicity (HTP), freshwater ecotoxicity and marine ecotoxicity with an amount of 3.66 × 10−4, 1.10 × 10−4, and 1.40 × 10−4 kg 1,4-DCB respectively. Electricity has a higher relative contribution to this technology due to the high amount of steel used during the construction of solar tower. Meanwhile, treating H2S leaves a positive impact towards every midpoint indicator, mainly on terrestrial acidification, fine particulate matter formation and ionizing radiation. The H2S splitting technology was set as the baseline to compare with various other H2 production technologies. Scenario analysis was assessed by setting the solar-powered electricity as the baseline and was compared with electricity from different sources such as wind, nuclear and the United Arab Emirates (UAE) grid for the H2S splitting plant. Moreover, uncertainty analysis using Monte Carlo simulation suggests that the probability of gaining results of HTP is the highest between 3.62 × 10−4 to 1.34 × 10−3 kg 1,4-DCB. It can be concluded that electricity powered by renewable sources significantly reduces the environmental burden from the scenario analysis conducted.

Strain-Based elevation monitoring during construction of the Salesforce Tower

Anticipated complexities associated with monitoring elevation changes during construction of the 326 m tall Salesforce Tower in San Francisco prompted the implementation of a strain-based system. This system utilizes strain gages embedded into the tower’s reinforced concrete walls and the resulting measurements are inputs into one of three shortening estimation models of varying complexity and applicability. This methodology was successfully utilized to monitor time dependent shortening due to axial, shrinkage, and creep strains in the tower. Strain-gage based systems assist with slender tower construction in urban areas because the tower’s slenderness coupled with adjacent obstacles stretch the limits of traditional or alternative instrument capabilities and they provide redundancy of measurement to ensure accuracy. This paper is a case study of how a strain-based elevation monitoring system helped this project to be successful. The most relevant findings are: 1) the shortening estimation models were in agreement with conventional survey measurements (±4.6 mm) within their recommended tower height and temperature range capabilities; 2) implementation of this system resulted in a net monitoring cost reduction on the order of 15 %, 400 less labor hours, and reduced potential for project delays; and 3) improvements are needed for supplying power to the sensors as there were interruptions, cut cables, and lack of sources that led to a 44 % sensor success rate. Given the need for structural health monitoring, the successful outcomes documented in this paper, and the potential for continued improvement by way of, for example, wireless and battery free sensing technologies, the work documented herein is believed to be an incremental advancement to the state-of-the-art of tall buildings.

Penolakan Masyarakat Terhadap Pembangunan Tower Telekomunikasi di Wilayah Ilir Barat II Kota Pelembang

Analysis of the impact of the Telecommunication Tower construction is one of the studies used to identify the impact of tower construction due to changes in land use, resulting in rejection by the community which will affect the development process. The purpose of writing this research is to find out the impact of the tower and how the construction process will go if the community refuses. In the area of Jalan Ki Gede Ing Suro Rt 28 Kel 32 Ilir Palembang, The research method used in this study is a qualitative research method. Qualitative research is used to understand the context of research by describing in detail and depth related to the conditions experienced by a context as well as what is happening in the field.

Comparison and simulation-based analysis of the sound field of Dong drum tower buildings

Drum towers are the most prominent cultural markers and the major site for cultural ceremonies in Dong villages. The visibility and audibility of drum towers are important factors influencing the location and construction of buildings in Dong villages. In this paper, the authors map and classify 21 drum tower buildings according to three characteristics: shape of the plan, elevation of the enclosure, and aspect ratio of the longitudinal section. Having used the sound field simulation software Odeon to filter two of the three characteristics that were identical, the authors simulated drum towers with different values of the third characteristic to study the factors influencing their sound field. The correlation between the construction of the drum tower and its characteristics of sound was established, and the characteristics of the sound field as well as their adaptability were assessed by comparing different forms of drum towers. This can provide technical support for the protection and repair of drum towers, their renovation and upgrade, and the construction of new drum towers in the Dong region.

Lower bounds on the maximal number of rational points on curves over finite fields

AbstractFor a given genus $g \geq 1$ , we give lower bounds for the maximal number of rational points on a smooth projective absolutely irreducible curve of genus g over $\mathbb{F}_q$ . As a consequence of Katz–Sarnak theory, we first get for any given $g>0$ , any $\varepsilon>0$ and all q large enough, the existence of a curve of genus g over $\mathbb{F}_q$ with at least $1+q+ (2g-\varepsilon) \sqrt{q}$ rational points. Then using sums of powers of traces of Frobenius of hyperelliptic curves, we get a lower bound of the form $1+q+1.71 \sqrt{q}$ valid for $g \geq 3$ and odd $q \geq 11$ . Finally, explicit constructions of towers of curves improve this result: We show that the bound $1+q+4 \sqrt{q} -32$ is valid for all $g\ge 2$ and for all q.

Применение динамических гасителей колебаний для повышения устойчивости башенных сооружений связи к ветровым воздействиям

Purpose: To investigate the application of dynamic vibration dampers in communication tower structures to protect them from the effects of wind loads. Methods: To analyze the design features of existing tower structures. To consider the effect of various factors including wind loads on the choice of tower structure design. To analyze the climatic parameters of the construction area and to determine the type of tower structure as the subject for conducting this research. To determine the quality criteria of vibration damping, on the basis of which the selection of design dynamic vibration dampener (DVD) construction is carried out, and to calculate its weight. To conduct the calculation study of the selected type of building with regard to wind loads and evaluate the effectiveness of the proposed solution of the dynamic vibration dampener to increase the stability of communication tower structures in areas with wind gusts over 25 m/s. Results: The results of the research of dynamic vibration dampener design aimed at improvement of operating conditions of telecommunication facilities in the areas with increased wind load are presented. Practical significance: It is shown that the use of dynamic vibration dampers in tower constructions of cellular communication makes it possible to reduce the vibration amplitude and the maximum horizontal displacements occurring in the tower structure under wind load.

Analyzing Energy Efficient Design Strategies in High-rise Buildings with Reference to HVAC System

The Global Warming, Climate Change, Energy Depletion, and Carbon emissions are the greatest risks to humanity in the 21st century. Urbanization in many ways increases the lack of energy resources and demands more construction of high-rise towers for a better standard of living. Buildings are responsible for around one-third of global greenhouse gas emissions. With the emergence of the energy crisis, the rise of environmental consciousness, energy-saving measures, and sustainable buildings became a topic of attention. Due to advancements in technology, the design of high-rise buildings has come across various changes with large glass openings, sealed windows, and deep plans which increase the dependency on air conditioning systems (HVAC) thus increasing the demand for more energy consumption inside the building due to mechanical ventilation and air conditioning. In this paper, an attempt has been made to understand the strategies used for designing energy efficient high-rise buildings that can lower the heating and cooling load and thus increase the performance of the high-rise building. The research is based on a theoretical approach and qualitative analysis which is identified from the literature review and secondary case studies, Case studies selected for the study are office high-rise buildings which are sustainable skyscrapers and have achieved lower energy consumption in heating and cooling load compared to the typical office building which shows how an increase in natural ventilation and other architectural design parameters such as building envelop, form, orientation and integration technology like Building Management System (BMS) system can make it more energy efficient high rise building.

Buckling resistance of angle bracing members with one‐leg bolted end connections

AbstractSteel angle members are widely used for the construction of lattice towers, mainly because of easy assembly on site and compact transport. Bracing members, especially, are connected directly or through gusset plates to the adjacent members with one or more bolts on one leg only. This type of connection provides some rotational restraint at the ends of the bracing, but also induces eccentricities. This paper presents the European normative framework covering the design against buckling of angle bracing members in lattice towers and identifies the differences between the different design rules available in existing normative documents. These differences are quantified through worked examples and the normative design procedures are evaluated against experimental results from the literature. The influence on the buckling resistance of various parameters, such as the support conditions and the steel grade, covering members made of both conventional mild steel as well as high strength (S460) steel, is also studied and quantified. Finally, useful conclusions are drawn about the accuracy of the available design rules.

Mechanical Model of Exposed-Dowel Half-Through Tenon Joints in Chinese Traditional Timber Structures Subjected to Bending

ABSTRACT The exposed-dowel half-through tenon (EHT) joint is a common and important connection configuration in southwest China. However, deformation and looseness in the EHT joint constitute the primary causes of failure in the joint connection performance. In this study, a mechanical model of the joints under bending was established and analyzed. The geometric, physical, and equilibrium equations were constructed, the bending moment-rotation relationship was obtained, and the bending moment-rotation envelope curve and the flexural capacity were calculated. A low cycle reciprocating experiment of the EHT joint was conducted to measure the moment-rotation hysteretic curve and envelope curve of the joints. A comparison of the envelope curves calculated using the model and test curves was conducted, and the results showed that the calculation curve was in good agreement with the test curve. The ultimate bending capacity errors of the joint in the forward loading stage and reverse loading stages were 11.2 and 5.8%, respectively. A parametric analysis of the joint using the established mechanical model showed that increasing the diameter of the wooden pillar and the width of the tenon greatly improved the flexural capacity of the joints while increasing the height of the small tenon and reducing that of the joints during the reverse loading stage. These research results provided a reference for the new construction and restoration of the Drum Towers in southwest China.

Optimal Design of Crossbeam Stiffness Factor in Bridge Towers Using a Reliability-Based Approach

Optimal design of the crossbeam is essential for the economical design of bridge towers as the crossbeam could considerably enhance the lateral stiffnesses of these towers by providing a special bracing for the tower columns. By using a reliability-based approach, this paper studies the optimal design of the crossbeam stiffness factor in bridge towers; this is defined as a dimensionless crossbeam stiffness relative to the tower column stiffness. A novel second-order matrix stiffness method (MSM) is applied to obtain a closed-form solution of the lateral stiffness of the bridge tower. The structural second-order stiffness matrix consists of combinations of the second-order element stiffness matrices and coordinate transformations. Subsequently, a reliability analysis to study the optimal design of the bridge tower is performed by considering the uncertainties arising from the design and construction of the bridge tower. The lateral stiffness of the bridge tower is set as an objective function while the total usage of materials is set as a constraint condition. Then, the influence of the crossbeam stiffness factor on the lateral stiffness of the bridge tower, including the fragility curve and the probabilistic behavior, is examined. Based on the reliability analysis, optimal design recommendations on the crossbeam stiffness of the bridge tower are presented.

Theoretical analysis of the power generation of pumping cycle kite power systems compared to traditional wind turbines in Aberdeen

The United Kingdom (UK) has pledged to reduce its greenhouse-gas emissions to net zero by 2050. However, in July 2022, the High Court ruled that the government’s net zero strategy failed to outline policies that would enable it to meet the target. As a result, the government published a new plan that sets out opportunities for innovative technologies like Floating Offshore Wind Manufacturing, and hydrogen, which will not only help us reach net zero. For wind, the government’s goal is to develop up to 50 GW of offshore wind by 2030. The challenge of such an expansion is huge. It means the United Kingdom will need to install an estimated 3,200 new, and much larger, wind turbines by 2030—roughly three new turbines every 2 days. Airborne Wind Energy (AWE) systems are part of a new class of wind energy converters that is receiving considerable attention in the renewable energy generation arena. AWE systems benefit from the steadier and stronger wind streams at high altitudes to generate more energy from wind while avoiding the expense of tower construction. This paper presents a feasibility study of using AWE systems in the UK and particularly in the City of Aberdeen to generate renewable energy. The characteristics of wind energy distributions were theoretically investigated by developing a wind speed distribution model, and then the annual power production of a kite system and a turbine system with 30 kW generator were analysed by applying the annual wind profile in Aberdeen to the performance models of these two systems. It was found that the annual power production of the kite system was two times higher than that of a normal turbine system.

Application of BPNN Optimized by Fireworks Algorithm on Structural Bearing Capacity Analysis of Transmission Tower under Icing Conditions

With the increasing power demand in city development, the construction and application of transmission towers need to meet higher requirements. Icing is an extreme meteorological condition in the world, and icing disasters cause various accidents such as tower collapse and line disconnection of large-area lines every year. Therefore, it is of great significance to study the ultimate bearing capacity of transmission towers under icing conditions. The structural bearing capacity under icing is greatly affected by meteorological conditions and environmental factors, which has strong randomness and complexity, and brings a series of urgent problems to the structural stability of transmission towers. In the paper, the ultimate bearing capacity analysis and failure path research are conducted on the 500 kV linear cathead tower structure, and a structural bearing capacity prediction model based on the fireworks algorithm (FWA) is established. In order to accurately predict the structural bearing capacity, reduce the adverse effects of line icing, and ensure the structural stability of the transmission tower, the FWA is introduced into the neural network model. The self-adjusting mechanism of the local search ability and global search ability of the FWA is used to optimize the optimization process of weights and thresholds in the neural network, and a structural bearing capacity prediction model based on the FWA improved backpropagation neural network (BPNN) is proposed. Through the analysis and calculation of the measured data of the transmission tower in a certain area, and the comparative study with the traditional BPNN and the BPNN optimized by other common algorithms, the analysis and calculation results of the FWA-BPNN model used in this paper are closer to the actual value, the multiple indicators are more superior, and the model is more stable, which can realize the rapid and accurate analysis of the axial stress of tower members and maximum displacement between member nodes of the transmission tower under the icing condition.

Analysis of the Influence of the MK Consultant's Role on the Performance of Telecommunication Tower Project Implementation

Construction Management is an alternative management technique pattern/system in the construction industry development process that combines the stages of the development process into one unit/integration. the effect of implementing a construction management system in the process tower construction Telecommunications can optimize management and control both in terms of cost, time and quality in achieving the goals/targets that have been determined. This writing analyze how far the role, influence of the implementation of the construction management system in the Telecommunication Tower construction process and provide descriptions of the benefits and optimization obtained in its application in terms of cost, quality and time aspects. Project management (planning, organizing, staffing, directing and controlling) has a very large effect on the success of cost performance, quality performance and time performance on the implementation of telecommunications projects with a determination value of 80.3% cost performance affects staffing, directing and planning. Based on the quantitative analysis, the variables that have a major influence on the quality performance used are staffing, directing; and) controlling.

In-situ live jacking technology of corner transmission tower

Aiming at the current situation that the foundation of the corner transmission tower is corroded, sunken, or the height of the tower line is insufficient, innovative low-cost technology is proposed to upgrade the foundation in-situ based on no power outages, and the analysis of the whole process of the in-situ live jacking construction of the transmission tower is studied in this paper. Firstly, through elastic mechanical equilibrium relationship, two form-finding methods of numerical analysis are derived and the results of several form-finding methods are analyzed and compared by a project example, among which the result error of the finite element method and the catenary method is negligible, while the error of the parabolic method is about 2% compared with the first two methods, but it can meet the engineering requirements. Secondly, the relevant laws of internal force and deformation of the lifting process are summarized, and a comparative analysis of theoretical and measured results verified the reliability and safety of the technology. Through the calculation program of the self-compiled parabolic method, the laws of tower line changes during the lifting process of the transmission tower are summarized, providing technical support for engineering practice and reference for related research.

Analysis on Mechanical Behavior of Relay Vertical Rotation for Steel Arch Tower

The vertical rotation method is a special option for steel tower construction in fabricated bridge. The tall tower is prefabricated on the ground and then pulled to its designed position using steel wires. Traditional vertical rotation method always uses a taller temporary structure to provide an upward pull force to lift the rotation member; however, the temporary structure would spend much time, cost, and work high above the ground. For instance, the Jinwu Bridge tower’s weight was so heavy that the ordinary rotating method was not feasible. Therefore, a relay traction system with two auxiliary struts was employed to rotate the tower. The chief strut was first rotated to an inclined angle of 60° by an assistant strut to decrease the lateral component force of tension. Then, the tower was pulled from horizontal to vertical by the chief strut. Furthermore, a numerical model was established to analyze the mechanical behavior of the inner force, stress, and deformation of the chief strut, assistant strut, and tower. The study identified critical conditions such as the reverse of axial force for the assistant strut, intervention of back cables, and release of cable tension. The relay traction system effectively reduced initial pulling stress, spending less cost and time. Besides, the analysis method can be an innovate reference for other vertical rotating projects.

Implementation of e-Government for Better Public Service at Lombok Barat

The aim of this study is to give recommendations for communication and information agency and all regional organizations at Lombok Barat so that the implementation of e-Government is more effective and improves employee performance in public services. This study uses a qualitative descriptive method with interview instruments, observations, and document review. Based on the interviews with key informants, observations, and review of Renstra, government support for the development of information and communication technology facilities and infrastructure has not been optimal due to limited budgets and a lack of coordination between regional organizations. Qualified apparatus and skills in information and communication technology are less common, and public administration services are still lacking and seem unprofessional, this has led to people still having negative opinions about government services. The government has to support the implementation of e-Government and the development of information and communication technology, especially the improvement of facilities and infrastructure, both office rooms and public service rooms, finance for the construction of towers and other infrastructure, socialization for public so that people can trust more with the government services, and applications and programs based on information and communication technology so that public services are more improved, smooth, and reliable.
 Keywords: effectiveness, e-Government, employee performance, community service

Life cycle assessment of ultra-tall wind turbine towers comparing concrete additive manufacturing to conventional manufacturing

Wind power is a quickly growing renewable energy resource within the continental United States and is expected to continue increasing as more wind farms are installed onshore and offshore. As a part of this growth, larger turbines benefit from economies of scale from taller towers. However, the development of ultra-tall wind turbine towers is hindered by transportation restrictions which limit the diameter and weight of the prefabricated tower sections. One proposed solution to this problem is to employ concrete additive manufacturing to build ultra-tall wind turbine towers on-site. To evaluate the potential environmental impacts of this approach, this study performed a life cycle assessment comparing four prototype 7.5-MW wind turbine towers designed with a height of 140 m: a conventional tubular steel tower assembled using bolted connections, two 3D printed concrete towers additively manufactured on-site with normal-strength (35 MPa) or high-strength (78 MPa) concrete, and a 3D cast concrete tower with normal strength (35 MPa) concrete cast into concrete formworks additively manufactured with high-strength (78 MPa) concrete. The 3D cast concrete tower segments are manufactured off-site and assembled on-site. The life cycle assessment examined the impacts of differences in materials inventory, structural designs, manufacturing methods, maintenance schedules, and end-of-life options for the four towers. The results indicate that the material production stage dominates, contributing over 92% of the total CO2 emissions and 67–93% of the energy consumption of the four towers. Compared with the steel tower, the normal-strength 3D printed concrete tower has 23% lower total life cycle CO2 emissions but 29% higher energy consumption; the high-strength 3D printed concrete tower has 16% higher life cycle CO2 emissions and 64% higher energy consumption. Parametric studies were also conducted to examine the effects of cement content by weight, distance from the concrete plant to the tower construction site, the number of tower sections, rated tower life, and tower end-of-life recycling rate. The results indicate that reducing cement content in 3D printed concrete such as by incorporating waste or recycled materials can significantly reduce the life cycle environmental impacts of ultra-tall turbine towers.

Reliability prediction and evaluation of communication base stations in earthquake prone areas

One of the primary tasks for effective disaster relief after a catastrophic earthquake is robust communication. In this paper, we propose a simple logistic method based on two-parameter sets of geology and building structure for the failure prediction of the base stations in post-earthquake. Using the post-earthquake base station data in Sichuan, China, the prediction results are 96.7% and 90% for the two-parameter sets and all parameter sets, respectively, and 93.3% for the neural network method sets. The results show that the two-parameter method outweighs the whole parameter set logistic method and the neural network prediction and can effectively improve the accuracy of the prediction. The weight parameters of two-parameter set by the actual field data significantly show that the failure of base stations after earthquake is mainly due to the geological differences where the base stations are located. It can be envisioned that if the geological distribution between the earthquake source and the base station is parameterized, the multi-parameter sets logistic method can not only effectively solve the failure prediction after earthquakes and the evaluation of communication base stations under complex conditions, but also provide site selection evaluation for the construction of civil buildings and power grid towers in earthquake-prone areas.

Cost Comparison of Different Types of Formworks

Formwork is the temporary moulds in the construction which are fabricated based on drawing and design of the structure and into which the concrete is poured to form the required structure. Formwork is an essential part of the construction as it has been in used by the Romans. The formworks must be strong enough to withstand all types of the loads. The joint must be in proper conditions to avoid any kind of leakages. The materials used for the formworks should be economical, easily available and durable. The formworks can be made up of different materials such as plywood, steel, aluminum, composite material etc. In Steel formwork the plates used for the slab support are made up of galvanized steels and these are fabricated as per the requirements. Aluminum plates are used in the aluminum framework along with the other components made up of aluminum. The selection of the suitable framework is important in any project because it bears about 25 to 30% cost of total cost of construction. In the present study, different types of formworks such as steel, plywood and aluminum were studied in a project and a comparison was made on the reusability and easiness in handling and maintenance. Also, comparison for the formwork used in construction of 5th and 11th floor tower based on the specific plan and drawing was done. The results showed that the aluminum formwork was found to be efficient and suitable among all formworks, although the cost was higher compared to other formwork’s materials.

Finite Element Simulation and Experiment of Temporary Active Transverse Brace of Inward-inclined Bridge Tower Construction

For the bridge tower with large inclination angle, the beam element in Midas finite element software is used to model and analyze the bridge tower structure, and its accuracy is difficult to guarantee. In this paper, taking the construction of a suspension bridge’s inward-inclined tower as the research background, the finite element simulation of the inward-inclined bridge tower is carried out by using the two modeling methods of the beam element and the solid element. The calculation accuracy of the beam element model, the specific position and the jacking force applied by the active transverse brace of the inward-inclined bridge tower are determined, and the field test of the tower bottom stress during the construction process is performed. The results show that: when the inclination angle of the bridge tower is small (5 °), the beam element element is used for modeling and analysis, which has fast calculation speed and high calculation accuracy; When the inclination angle is 15 °, the error of the beam element model exceeds 30%, and it is recommended to use the solid model for calculation; the active cross brace plays a key role in controlling the stress at the bottom of the tower column before the lower cross beam is applied. And after the construction of the cross beam, the active cross brace forms a closed frame structure with the lower tower column, and the subsequent cross brace has little impact on the stress at the bottom of the tower column; Compared with increasing the number of temporary cross braces, increasing the jacking force can improve the stress at the bottom of the tower. And by adjusting the position of the active cross brace and applying the appropriate active jacking force, the stress at the root of the tower column can be greatly improved.