Mobile Crane Research Articles

Rare-Class Extraction Using Cascaded Pretrained Networks Applied to Crane Classification

Overweight vehicles are a common source of pavement and bridge damage. Especially mobile crane vehicles are often beyond legal per-axle weight limits, carrying their lifting blocks and ballast on the vehicle instead of on a separate trailer. To prevent road deterioration, the detection of overweight cranes is desirable for law enforcement. As the source of crane weight is visible, we propose a camera-based detection system based on convolutional neural networks. We iteratively label our dataset to vastly reduce labeling and extensively investigate the impact of image resolution, network depth and dataset size to choose optimal parameters during iterative labeling. We show that iterative labeling with intelligently chosen image resolutions and network depths can vastly improve (up to 70×) the speed at which data can be labeled, to train classification systems for practical surveillance applications. The experiments provide an estimate of the optimal amount of data required to train an effective classification system, which is valuable for classification problems in general. The proposed system achieves an AUC score of 0.985 for distinguishing cranes from other vehicles and an AUC of 0.92 and 0.77 on lifting block and ballast classification, respectively. The proposed classification system enables effective road monitoring for semi-automatic law enforcement and is attractive for rare-class extraction in general surveillance classification problems.

Investigating Satisfaction Levels of Safety Requirements in Mobile Cranes and its Relationship with Organization’s Safety Culture

Background: disregarding safety requirements has made accidents of workshop mobile cranes as one of the main factors of injuries and death in civil-industrial projects. Since safety culture considered one of the most important activist indices while investigating the commitment of superior managers and other members of the organization to regard safety requirements, the present study aims at investigating the organization’s safety culture in civil and industrial projects and its relationship with regarding safety requirements of mobile cranes. Methods: the current study is descriptive-analytical and cross-sectional research conducted within 7 civil-industrial projects from 2018 to 2019. To investigate satisfaction levels of safety requirements, 141cranes have been used through a 72-item researcher-made checklist adapted from ASME B30.5 2018 standard and protective regulation of transportation vehicles and moving materials and objects of workshops. The research team has confirmed the validity and reliability of the checklist with CVR=0.68, CVI=0.82, and Cronbach’s alpha=α-0.90. To estimate safety culture levels 677 individuals of staff such as cranes operator, technician, expert, minor managers, middle managers, and superior managers have participated in this study through random sampling method, interview, and completion of safety culture questionnaire. To analyze data Kolmogorov-Smirnov tests, one way ANOVA and linear regression utilizing SPSS v25 have been employed (P-value < 0.05). Results: age average of study individuals equaled with 39.8 and average of their work experiences equaled with 12.29. Results out of this study revealed that there is a positive and meaningful relationship between organizations’ safety culture and consideration levels of safety requirements in mobile cranes. So that parameter of management commitment (0.001), safety preference degree (0.004), staff training (0.012) and information exchange level (0.041) have the most relationship with consideration levels of safety requirements. But there was no meaningful relationship between work conditions and consideration levels of safety requirements (0.075). conclusion: based on results of this study it seems that accidents resultant from mobile cranes occur more in uncommitted organizations so it is important to develop organizations’ safety culture through performance of academic interventions and inform organizations’ staff especially superior management and consequently increase the safety factor of mobile cranes in civil-industrial projects.

Automated rigging design for heavy industrial lifts

Modular-based heavy industrial construction projects typically involve the use of mobile cranes to lift and place large heavy prefabricated modules. These modules must be lifted vertically, raised evenly, and maintained in a level position during the lift in order to prevent them from deflecting and, more importantly, to mitigate safety issues regarding potential rigging failure. In this respect, a comprehensive crane lift study at the planning stage of the project is required to ensure the lifts are successful and to improve safety and productivity. One of the most tedious and time-intensive tasks involved in conducting the lift study is the design of the rigging assemblies, which are the link between the crane hook and the module. In practice, however, this task is performed manually and relies heavily on guesswork, which is error-prone and time-consuming, especially when the center of gravity is offset from the center of the module. Poorly designed rigging assemblies are only detected at the job site when the module does not raise evenly at the beginning of the lift, which then results in wasted time and productivity loss as the assembled components have to be unrigged and properly adjusted. To overcome these limitations, this paper proposes an automated mathematical-based rigging assembly design system that consists of: (i) collecting module and available rigging component information; (ii) the solver analysis, which calculates the sling angles and performs the calculations required to balance the module; (iii) the rigging assembly designer, which determines the required capacity of the rigging components and selects the suitable riggings from the database; (iv) rigging assembly design alternatives; and (v) the 3D visualizer, which creates a 3D model of the designed rigging assembly. This framework enables lift engineers to create rigging assembly designs more precisely and expeditiously. The methodology is validated in a case study.

Simulation of railroad terminal operations and traffic control strategies in critical scenarios

Railroad terminals contribute to the competitiveness of intermodal transport and play an important role in the transport chain to achieve seamless cross-modal processes, because they must guarantee a fast, safe, and efficient transfer of intermodal loading units. The equipment required, such as gantry and mobile cranes can be critical to the terminal process. However, numerous cranes cannot be designated to guarantee a high level of redundancy, because of their relevant cost.This paper presents a micro-simulation approach for evaluating the resilience of typical railroad terminals in a critical scenario, such as the temporary unavailability of a gantry crane. Resilience can be defined as the capability of the system to recover its functionality despite a disruption and a gating strategy is proposed in this case to maintain the desired level of service inside the terminal. Therefore, this traffic control strategy is investigated to ascertain its ability in enhancing the terminal resilience when a disruption occurs in a process.The proposed simulation method is not only used for performing a typical sensitivity analysis under disturbed conditions, but also for assessing the flexibility of the simulated terminal. A comparison is performed for a baseline traffic scenario in equilibrium conditions by setting equal average values for the arrival and service rates, thereby exploring the operation of the infrastructure near its capacity.In the simulation tool, the relevant features of the typical phases of the internal process are represented, and the traffic flow data of truck arrivals are disaggregated based on specific operations using dedicated service lines. To compare the modeled scenarios, some quantitative key performance indicators (KPIs) are selected and quantified in terms of quality and energy impacts.

To the issues of ensuring the stability of jib mobile cranes, taking into account various aspects of their operation

The article is considered requirements of standards for crane stability analysis of mobile cranes. Proposed supplement about crane stability tests to Federal norms and rules for safety lifting hoisting equipment.

Development of technological schemes for open-pit mining of deposits using “mobile crushing-reloading-conveyor complexes”

This article analyses the use of cyclic-flow technology schemes with mobile crushing and reloading complexes in open cast mining. An analysis of the application of cyclic-flow technology schemes with mobile crushing and reloading complexes in open cast mining shows that the main directions of its radical improvement are the development, creation and implementation of fundamentally new mining transport equipment and technological schemes for its quarries, which include: “mobile excavators crushing and transhipment plants and conveyor systems". Technological schemes for the development of rocks with an end arrangement of mobile complexes using a single bucket excavator and conveyor transport, with an end arrangement of mobile complexes and an increased width of the working platform during conveyor transport, with an end arrangement of mobile complexes and the presence of a mobile interstage loading crane with sequential mining at three horizons, a methodology has been developed for determining the working time and annual productivity of mobile crushing and handling conveyor complexes and a new technological scheme for the development of overburden ledges using mobile crushing and handling conveyor complexes. To reduce the time for idling the complex and reduce the number of exit ledges, a new technological scheme for the development of overburden ledges with the use of mobile complexes is recommended. As a result of the calculations according to the developed method, when working out two benches with different block lengths, the dependence of the annual productivity of the complex on the block length was established.

Best Practice Standards and Methodology for Crane Operator Training—A Global Perspective

Crane operators control mobile or stationary cranes to lift, move and place objects at locations such as building and construction sites, wharves and shipyards. This activity occurs all over the world and is a high risk task with many noted examples of serious incidents and accidents. There are identifiable key causes that have been noted through analysis of the well documented cases and many of these causes are preventable through effective training programs. Internationally, there are not currently consistent approaches to crane operator training program content or duration. Leading causes of crane accidents are firstly discussed and identified as areas for inclusion in training programs. A number of current training approaches from a range of countries are then considered and these are used to outline the basis of a generic competency standard for crane operation, as it was found that there are not common standards in place. The proposed competency standard can be adapted by training regulators, training providers, government agencies, industry bodies and enterprises as a benchmark for the development of effective training programs.

Izračunavanje dinamičkog ponašanja pokretnih kranova sa rešetkastom strelom tokom podizanja tereta

Lattice boom mobile cranes are mainly used to move heavy payloads with a large hoisting radius. During this work, crane motions cause dynamic forces on the crane's structure. In order to guarantee the safety of cranes, exact calculations are absolutely essential for the boom system. The calculation standards stipulate the use of special dynamic factors to estimate the dynamic loads. Several research projects have shown, that the standards often describe the dynamic effects only approximately. In order to calculate the dynamic behaviour accurately, without a disproportionate increase in computing time, special vibration models have been developed in a current research project. This paper presents a new vibration model for the process of hoisting suspended loads. The model is based on the response spectrum method and describes the dynamic effects in an exact way.

Response surface methodology based on polyamide incorporated with biolubricant for optimisation of operating parameters in heavy vehicles

In this paper, the coefficient of friction (COF) and wear of pure and filled polyamide incorporated with and without bio lubrication prediction models based on response surface methodology (RSM) are exhibited in heavy vehicles. A special purpose vehicle is a motor vehicle or trailer, other than an agricultural vehicle or a tow truck, built for a purpose other than carrying goods, or a concrete pump or fire truck (both of which carry water). Examples of a special purpose vehicle include a mobile crane, a concrete pump, drill rig or fire truck. The models were developed based on three-level design of experiments conducted on pure polyamide such as Polyamide6, Polyamide66 and filled polyamide like Polyamide66 filled with glass fibre 30 and Polyamide66 filled with molybdenum disulfide, considering with load, speed and sliding distance as process parameters. Numerical models of second order RSM clearly show that the prediction capabilities of response surface methodology models are more desirable. This implementation identifies the insignificant main factors and contact factors or insignificant quadratic expressions in the model and in this manner can diminish the complexity of the problem.

Promene mikrostrukture i mehaničkih svojstava u zoni uticaja toplote zavarenog spoja čeličnih traka klase S960MC

The TMCP (thermo-mechanically controlled processed) steels belong to the group of ultra-high strength steels, which exhibit exceptional combination of high tensile and yield strength, toughness and ductility. These steels were introduced in the heavy machinery constructions, such as heavy mobile cranes, chassis trucks and other to reduce their weight, what increases their loading capacity and ecology of transport. The high tensile and yield strength of this type of steels is obtained by the combination of the chemical composition, heat treatment and the mechanical processing. However, the heat input into the material during the welding significantly affect properties of the steel and the whole joint. In this paper are presented results of mechanical properties evaluation and structural analysis of the welds of the thin sheets made of the S960MC steel, which were welded using the GMAW procedure. The microstructural evaluation referred significant changes in the HAZ. This area contains the three sub-zones, coarse grain (CGHAZ), fine grain (FGHAZ) and intercritical zone (ICHAZ). Analysis of microhardness and the tensile tests results showed, that ICHAZ is the most critical area of the whole welded joint.

Development of an efficient flexible dynamics model of a mobile crane with adaptive modal integration

Development of an efficient flexible dynamics model of a mobile crane with adaptive modal integration

Structural analysis of built-up members with angles

Built-up steel members are frequently used in lifting equipment structures, such as tower cranes, gantry cranes, mobile cranes jibs and so on. Mining stiffleg derricks are the subject of the present paper. Derricks design is usually carried out using commercial finite element analysis packages (FEAP): these packages often offer only beam formulations developed for bi-symmetric cross-section members. So, important effects associated with buckling interaction between axial force and bending moments, as well as with the presence of warping torsion, are currently neglected in analysis design. Moreover, these interactions are not yet included in standard provisions. The paper is focused on built-up members for stiffleg derricks made by angles, focusing on the analysis phase. Key features of single angles are presented, stressing out the importance of capturing the buckling loads for compression, bending and compression plus bending. An applicative part is also proposed: two stiffleg derricks, differing only in panel geometry, have been studied, considering each in six geometrical configurations. Structural analyses have been carried out by using two FEAPs differing for the degree of refinement of the implemented beam formulations. Research outcomes highlight the important influence of effects that are currently neglected in routine design.

Design of Self-erecting Tower for a Wind Turbine

The rise in total installed wind energy structures globally demonstrated the dominance of wind energy among the means of sustainable energy production. However, the major challenge in the installation of horizontal-axis wind turbines is the use of mobile crane to install the components. This research reports on a new method of installing the wind turbine without the use of a mobile crane. A self-erecting design was proposed, in which the whole components of tower and turbine will be assembled at the installation site. The highest peak wind speed adopted for the site under research was 56 km/h, the thickness of base plates material that connected the tower to the base was 11 mm, and the calculated size of jack recommended to lift the tower was 2575 kg. Also, the stiffness of the weak section of the tower was calculated to be 8633 kN/m, and the frequency of vibration of the tower was found to be 191 Hz. A 48 V, 1600 W A.C wind turbine was selected to be installed on the tower under design for the analysis of forces acting on the tower. The wind speed data uses for the chosen site was recorded during the raining season in Kano. The design considered a tubular steel tower, from steel pipes that are symmetrical in diameter, but with the diameter of the pipes increasing toward the base: 51 mm, 73 mm and 89 mm. The pipes were to be assembled together using steel reducer sockets, and then to be welded to obtain a permanent solid tower. The erection of the tower was designed to be achieved by the use of a jack, preferably electric jack that require less effort to operate, attached at the fulcrum, while the tower tilted at the pivot that connected the tower to the base. The proposed structural advancement can meet the design requirements and lower the construction cost of the tower significantly.

Dynamic problem of mobile crane and application of simulation

Dynamic problem of mobile crane and application of simulation

Моделирование усилий в опорах машин основного технологического назначения на примере стрелового самоходного крана

Моделирование усилий в опорах машин основного технологического назначения на примере стрелового самоходного крана

Heavy Military Land Vehicle Mass Properties Estimation Using Hoisting and Pendulum Motion Method

Mass properties such as the centre of gravity location, moments of inertia, and total mass are of great importance for vehicle stability studies and deployment. Certain parameters are required when these vehicles need to be arranged inside an aircraft for the carrier to achieve proper mass balance and stability during a flight. These parameters are also important for the design and modelling process of vehicle rollover crash studies. In this study, the mass properties of a military armoured vehicle were estimated using hoisting and pendulum method. The gross total weight, longitudinal and vertical measurements were recorded by lifting the vehicle using a mobile crane and the data were used to estimate the centre of gravity. The frequency of vehicle oscillation was measured by applying swing motion with a small angle of the vehicle as it is suspended on air. The centre of gravity and mass moment of inertia were calculated using the vector mechanics approach. The outcomes and limitations of the approach as discussed in details.

Analisa Kapasitas Pelayanan Kegiatan Bongkar Muat Kapal Barang di Pelabuhan Maccini Baji

Capacity Analysis of cargo ship loading and unloading services activities at the Maccini Baji Port. This study aimed to describe the Capacity Analysis of cargo ship loading and unloading services activities at the Maccini Baji Port, (1) How Baji Maccini port productivity based on number of loading and unloading cargo, (2) Factors that affect the productivity at the port Maccini Baji, and (3) What advice and recommendations on productivity Maccini port Baji. Stages of the data analysis are: (a) Identify the relationship between the amount of cargo and truck fleet size, the amount of cargo and service time, the amount of cargo and the number of workers unloading; (b) Perform forecasting the amount of cargo to medium term; (c) Count the number of truck fleet needs, service time, and the number of workers unloading based on the equation in the first step, based on the results of load forecasting; (d) Compare the service charge using the launch system and by using a mobile crane. The results showed that, the amount of service time available for 5,610 hours/year, truck payload capacity of 49,500 tons/year, and the number of loading and unloading labor (labor) of 9,900 people/year. Projections charge in 2020 amounted to 106,632 tonnes, for the medium term (2024) amounted to 292,291, and for the long term (2029) amounted to 858,913. Total fleet needs (truck) for a long term (10 years) as many as 28,764 trucks / year.

Comparison of epidemiology and injury profile among injured patients involved in incidents by special purpose vehicle

This study examined injuries related to mobile machinery or special purpose vehicle (SPV) mainly used in agriculture (tractor), industry (forklift or lift truck, mobile crane), and construction (gr...

Dynamic Processes of Loader Cranes Manipulators with Excessive Backlashes and Elastic Damping in Their Hinges

This research is aimed at developing a mathematical model and the methodology for computer simulation of hydraulically driven manipulators of mobile cranes having excessive backlashes in cylindrical joints. The authors proposed a structural design and considered the mechanism of reducing the additional impact load in the hinges by means of elastic damping of oscillatory processes. This method allows estimating the degree of influence of the backlash and stiffness of the elastic damper on the change in the quantitative characteristics of the dynamic loading of the manipulators metalwork and the motion parameters of the transported load. While in operation, the excessive backlashes may cause an increase in the level of dynamic loading of manipulators up to 2 times or more. However, the rational choice of the elastic dampers stiffness allows an effective solution to this problem to the point of complete elimination of the additional impact load.

Nurtured in Nature

A project to replace a bridge across the River Severn between Highley and Alveley in Shropshire, UK is described. The early reinforced concrete, balanced cantilever bridge is in poor condition with heavy spalling of the concrete. It carries the Route 45 national cycleway and enables access onto a country park built on the site of the old Highley Colliery. The new bridge will be built alongside the existing bridge. Mowlem was appointed as contractor to design and build a new three-span, continuous, reinforced concrete bridge. The provision of a curved, painted steel parapet with tubular rails was specified. The side spans were cast in situ. The ribs and diaphragm beams for the central span were constructed on a specially prepared casting bed on the Alveley bank and lifted into place using a mobile crane. Hydraulic jacks were used to adjust its level. The bridge was designed to accommodate a reasonable amount of movement as the Highley bank is susceptible to geological movement. Construction was started in 2005.