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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Productivity improvement of tower crane in tall buildings

Manrique, A., Manrique, A., Saman, J., Rodriguez, S., Melendez, K. 28 February 2020 (has links)
The tower crane is an electromechanical equipment that is used for the vertical transport of materials in a construction project and together with the two riggers form the work team to carry out this task. One of the main problems in the construction of multifamily buildings corresponds to the use of the tower crane because vertical transport causes non-contributory times, which is, dead times and waits above expectations. This research analyzes the current vertical transport process and proposes its optimization through some management tools with the aim of improving the productivity of the use of the tower crane by reducing non-contributory times. To this end, the productivity of the work team is recorded in several projects with similar characteristics, then the main problems are selected to analyze them and finally the process is optimized. The results determined that non-contributory times can be reduced by 10% if there is an orderly and continuous process.
2

Control of Rotary Cranes Using Fuzzy Logic and Time-Delayed Position Feedback Control

Al-Mousa, Amjed A. 11 December 2000 (has links)
Rotary Cranes (Tower Cranes) are common industrial structures that are used in building construction, factories, and harbors. These cranes are usually operated manually. With the size of these cranes becoming larger and the motion expected to be faster, the process of controlling them became dicult without using automatic control methods. In general, the movement of cranes has no prescribed path. Cranes have to be run under dierent operating conditions, which makes closed-loop control preferable. In this work, two types of controllers are studied: fuzzy logic and time-delayed position feedback controllers. The fuzzy logic controller is introduced first with the idea of split-horizon; that is, to use some fuzzy engines for tracking position and others for damping load oscillations. Then the time-delayed position feedback method is applied. Finally, an attempt to combine these two controllers into a hybrid controller is introduced. Computer simulations are used to verify the performance of these controllers. An experimental setup was built on which the time-delayed position feedback controller was tested. The results showed good performance. / Master of Science
3

Časové posouzení využití zdvihacích mechanismů v pozemním stavitelství / Time Assessment of Lifting Mechanisms Efficiency in Civil Engineering

Štěrba, Martin Unknown Date (has links)
The dissertation thesis deals with the time assessment of designed lifting mechanisms in monolithic constructions in Civil Engineering. The main reason for choosing this subject matter is a current trend in construction that in terms of administrative and housing construction tends to build monolithic buildings. Lifting mechanisms are crucial in such buildings nowadays. The efficiency of lifting mechanisms is often neglected in the preparatory phase of construction time schedules, which leads to inefficient capacity utilization of the machine. Nevertheless, this is directly related to meeting the agreed deadlines, which in turn leads to complications that often result in a considerable financial loss for the contractor. In order to solve this subject matter it was necessary to perform monitoring on an appropriate sample of constructions. In the case of this work it was a total of six buildings, four of which were further analysed. Furthermore, individual partial construction processes requiring tower crane operation were analysed. A time assessment methodology including a proposal of possible prioritization of selected activities has been developed. Based on the knowledge gained from the monitoring of the buildings as well as from the analysis of individual items, a simulation model was developed. This model mathematically and graphically evaluates the ability of the designed tower crane to serve a given number of partial construction processes within a specified evaluation section in which the smallest evaluated section equals to one work shift. The benefit of this work is to enable efficient deployment of the tower crane in the preparatory phase of construction. Another benefit is also a prompt operative assessment of the load of the tower crane by a works foreman within a given shift. This should lead to a more efficient deployment of tower cranes during construction and as a consequence it should result in keeping the agreed terms. This is closely associated
4

Innovation in construction techniques for tall buildings

Skelton, Ian R. January 2015 (has links)
The skyline of many 'world cities' are defined and punctuated by tall buildings. The drivers for such dominant skylines range from land scarcity and social needs; high real estate values; commercial opportunity and corporate demand, through to metropolitan signposting. This fascination with tall buildings started with the patrician families who created the 11th Century skyline of San Gimignano by building seventy tower-houses (some up to 50m tall) as symbols of their wealth and power. This was most famously followed in the late 19th Century with the Manhattan skyline, then Dubai building the world's highest building, then China building some eighty tall buildings completed in the last 5 years, then UK building Europe's highest tower, the Shard and finally back to Dubai, planning a kilometre tall tower, potentially realising Ludwig Mies van der Rohe's 'Impossible Dream' of the 1920's and Frank Lloyd Wright's 1956 'Mile High Illinois'. This ambition to build higher and higher continues to challenge the Architects, Engineers and Builders of tall buildings and is expected to continue into the future. The tall building format is clearly here to stay.
5

Modifikace provozních podmínek stroje ALIMAK - SCANDO / Modification of work conditions ALIMAK - SCANDO machine

Němec, Jan January 2011 (has links)
The theme of this master´s thesis with theme the modification of work conditions, it´s aim is to analyse existing and modified operating conditions of the machine and make their comparison. This work includes frame stress analysis, surface burdened by wind, the stability of the location and control of capacity at endurance.
6

Control of Gantry and Tower Cranes

Omar, Hanafy M. 27 January 2003 (has links)
The main objective of this work is to design robust, fast, and practical controllers for gantry and tower cranes. The controllers are designed to transfer the load from point to point as fast as possible and, at the same time, the load swing is kept small during the transfer process and completely vanishes at the load destination. Moreover, variations of the system parameters, such as the cable length and the load weight, are also included. Practical considerations, such as the control action power, and the maximum acceleration and velocity, are taken into account. In addition, friction effects are included in the design using a friction-compensation technique. The designed controllers are based on two approaches. In the first approach, a gain-scheduling feedback controller is designed to move the load from point to point within one oscillation cycle without inducing large swings. The settling time of the system is taken to be equal to the period of oscillation of the load. This criterion enables calculation of the controller feedback gains for varying load weight and cable length. The position references for this controller are step functions. Moreover, the position and swing controllers are treated in a unified way. In the second approach, the transfer process and the swing control are separated in the controller design. This approach requires designing two controllers independently: an anti-swing controller and a tracking controller. The objective of the anti-swing controller is to reduce the load swing. The tracking controller is responsible for making the trolley follow a reference position trajectory. We use a PD-controller for tracking, while the anti-swing controller is designed using three different methods: (a) a classical PD controller, (b) two controllers based on a delayed-feedback technique, and (c) a fuzzy logic controller that maps the delayed-feedback controller performance. To validate the designed controllers, an experimental setup was built. Although the designed controllers work perfectly in the computer simulations, the experimental results are unacceptable due to the high friction in the system. This friction deteriorates the system response by introducing time delay, high steady-state error in the trolley and tower positions, and high residual load swings. To overcome friction in the tower-crane model, we estimate the friction, then we apply an opposite control action to cancel it. To estimate the friction force, we assume a mathematical model and estimate the model coefficients using an off-line identification technique using the method of least squares. With friction compensation, the experimental results are in good agreement with the computer simulations. The gain-scheduling controllers transfer the load smoothly without inducing an overshoot in the trolley position. Moreover, the load can be transferred in a time near to the optimal time with small swing angles during the transfer process. With full-state feedback, the crane can reach any position in the working environment without exceeding the system power capability by controlling the forward gain in the feedback loop. For large distances, we have to decrease this gain, which in turn slows the transfer process. Therefore, this approach is more suitable for short distances. The tracking-anti-swing control approach is usually associated with overshoots in the translational and rotational motions. These overshoots increase with an increase in the maximum acceleration of the trajectories . The transfer time is longer than that obtained with the first approach. However, the crane can follow any trajectory, which makes the controller cope with obstacles in the working environment. Also, we do not need to recalculate the feedback gains for each transfer distance as in the gain-scheduling feedback controller. / Ph. D.
7

Galéria Lučenec - vybrané části stavebně technologického projektu / Galéria Lučenec - selected parts of the construction technology plan

Jakobei, Michal January 2022 (has links)
The main purpose of this thesis is to describe in detail the processes of selected parts of the construction technology project for the construction of the department store Galéria Lučenec, based on the project documentation provided by the principal engineer. It is a large-scale new building with a cast-in-place reinforced concrete load-bearing structure with steel elements located in the center of Lučenec. The diploma thesis consists of the main parts such as the technical report of the construction technology project, a detailed coordination situation of the construction site, and a detailed time and financial plan of individual buildings. Within the main building, a study of the main technological stages of construction, elaboration of the project site equipment together with the associated design documentation and the technical report, design of the main construction machines and mechanisms, time schedule of the main building processes, and an item budget are described. Within the technological regulation and the control plan, the diploma thesis is focused on the cast-in-place structures of the superstructure. In the final part of the project, there are chapters devoted to topics such as occupational health and safety on the construction site, evaluation of LEED 2009 certification, the procedure for securing the construction pit, and the assessment of the main vertical lifting mechanisms.
8

Budova VZP ČR Jihlava - stavebně technologický projekt / Building VZP ČR Jihlava – construction and technological project

Kotrč, Ondřej January 2012 (has links)
The aim of the diploma thesis is a constructional and technological project of regional branch VZP in the town Jihlava. The project includes a building site outfit, technological rule for prefabricated skeletel constructions, budget, time schedule, kontrol and test plans, design of machine works, contract for work and safety report. As a part of the diploma thesis is also confrontation contact heta cladding system and heat cladding system with a ventilated air gap. The last supplement is safety report at demolitions.
9

Bytový dům v Blansku - stavebně technologický projekt / Apartment building in Blansko - construction technology project

Sokol, David January 2018 (has links)
The content of this work is the elaboration of a technology-oriented project for the construction of an apartment building with four above-ground floors in Blansko. This project includes a technical report, road mapping solutions, technological regulations, a drawing and technical report of the building site equipment, a timetable, a design of the machine assembly, control and test plans, a material resource assurance plan, and a technical report on health and safety at the building site.
10

Bytový dům Suchdolské Zahrady - stavebně technologický projekt / The Apartment Block Suchdolské Zahrady - construction technological project

Jurásek, David January 2013 (has links)
The object of this thesis is to implement the contruction of the apartment block in Prague's area Suchdol. This report contains the technical report for construction technological project, technical report of site facilities, technological regulation, budget, time management, project of machinery assembly, inspection and test plan, environmental plan, occupational safety, study of main technological stages and comparative study.

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