Crane Stability Research Articles

Computer-aided rotary crane stability assessment

This paper introduces a computer-aided approach for evaluating the stability of rotary cranes. Utilizing the Motion add-in within the SolidWorks package, a comprehensive numerical stability analysis was carried out. The interaction dynamics between the crane’s support system and the ground were modeled employing linear springs, while the rope system was characterized by a blend of linear spring and damper elements. The term “temporary loss of stability” was introduced to describe scenarios wherein one support loses contact with the ground. Furthermore, ramifications of overlapping control signals on crane operational safety were investigated. Validation of the numerical findings was accomplished through experimental tests conducted on an actual crane. This integrated methodology not only enhances the understanding of crane stability but also offers practical insights for optimizing crane operations in real-world settings.

Analysis of Occupational Injuries in Construction and Offer of a Technical Solution Increasing Tower Crane Stability

The article contains analysis of the number of occupied human resources and the level of occupational injuries by kinds of economic activity based on ROSSTAT data. The analysis resulted in a low level of occupational safety in the construction sphere. To ensure safe tower crane operation with account for impact of random factors and loads a technical solution was offered that provides for additional tower crane stability by moving the counterbalance over traveling rollers in the direction opposite to probable collapse, thus preventing crane tipping over. As a result, it becomes possible to change the value of holding moment at high loads on the tower crane boom. This technical solution will ensure reliability in the process of operation of lifting machines and it meets all occupational health and safety requirements on construction sites.

Stability Analysis on Tower Crane Foundation Using Finite Element Method

Currently, the construction of high-rise buildings is increasing as the modernization of the city. Especially in the heart of Kuala Lumpur City, construction is more focused on the construction of high-rise buildings due to over-crowded areas. To meet demand due to the activity, the number of tower cranes brought into Malaysia has increased. The tower crane is used to lift construction items and requires a solid base to ensure tower crane stability. Analysis obtained from the Department of Occupational Safety and Health (DOSH), the rate of accidents involving in particular the use of cranes tower cranes occurred due to the failure of the crane foundation. The main objective in carrying out this project is to ensure the stability of the foundations for ensuring the safe use of tower cranes in reducing accident site, determine the calculation of the basic design of the site and the last one is to analyze the stability of the soil through the interaction between the soil and the basic structure of the site. Design calculations from qualified engineers as well as engineering software for analysis tests are an important element in the success of this research project. Among the parameters required are ground properties information for the installed tower cranes, engineering drawings for tower crane structure and Plaxis 3D computer software for analysis purposes. The implication of this project is to achieve the department’s quality policy in providing and maintaining a quality, safe and healthy work and system without any harm and risk.

ANALYSIS ON ANTI-OVERTURNING STABILITY OF A TRUCK CRANE BASED ON ZERO MOMENT POINT THEORY

Truck crane stability has been a hot research issue. It is a conventional method used to calculate the moments equilibrium when analyzing stability. However, errors can occur because of the lack of dynamic simulation in conventional methods. Hence, to minimize errors, this study utilized the zero moment point (ZMP) theory to calculate the maximum lifting capacity of the truck crane considering the dynamic load, and proposed an anti-overturning detection method based on the theory. First, the model of the truck crane was established and the solution formula of ZMP was obtained. From the Lagrange equation, the dynamic model of payload oscillations was analyzed during crane operations. Second, the ZMP theory was used to analyze the stability of the truck crane and derive the maximum payload. Next, the experiment was conducted to measure the pressure of the four outriggers and their center of pressure (CoP) during hoisting, luffing, and slewing operations were calculated. Compared to stable movement, the CoP would vibrate irregularly, consequently reducing the lifting capacity of unstable motion. Finally, the anti-overturning detection method is proposed based on ZMP and CoP. Results demonstrate that the reduction of lifting capacity is caused by the dynamic load. The payload swing has a larger effect on the maximum lifting capacity than hoisting, luffing, and slewing motions. The maximum payload can decrease with the increase of the swing angle. The proposed method provides a correct judgment on the stability of the truck crane, which can accurately predict the overturning state of the crane and reduce the risk in the operation. Keywords: truck crane, overturning, zero moment point, center of pressure, stability

Finite element analysis of the chassis in telescopic crawler crane

In modern industry, crawler crane is an essential equipment. Chassis is an important component for crawler crane stability. In this paper, the finite element software ANSYS is used to establish the research model of SCC250TB crawler crane chassis. According to the stress characteristics of crawler crane, six typical working conditions are selected, and the corresponding stress nephogram is obtained through calculation. The model provides the basis for the strength and lightweight design of the crane’s chassis. It plays an important role in practical engineering projects.

Study of the crawler crane stability affected by the length of compensating ropes and platform rotation angle in the mode of movement with payload

Payload uncontrolled oscillations arising during movement of a loaded self-propelled crawler crane at a construction site were reduced by equipping the crane with two additional compensating ropes equal in length and connecting the rotating platform to the load gripping device. This also increased the stability of the entire system. The stability margin moment was used to evaluate the crane stability at individual tipping axes of the crawler support contour. While moving along a random microrelief surface, under the varied length of the compensating ropes and the platform rotation angle, the length reduction increased the mathematical expectation of the stability margin moment for the most loaded lateral tipping axis. The smallest values of the stability margin moment were obtained at the platform rotation angle close to 90 degrees, with the crane stability index being most affected by the compensating rope length. At a zero platform rotation angle, the compensating rope length effect on the stability at the most loaded lateral axis was insignificant. The regression equation of the average stability margin moment affected by the compensating rope length and the platform rotation angle was obtained. The results can be used in the design of advanced self-propelled cable electric crawler cranes.

ТЕОРЕТИЧЕСКОЕ И ЭКСПЕРИМЕНТАЛЬНОЕ ОБОСНОВАНИЕ ИЗМЕНЕНИЯ УСИЛИЙ В ОПОРАХ СТРЕЛОВОГО САМОХОДНОГО КРАНА

In the paper on the basis of the Rostechnadzor report data there is revealed the topicality of the work connected with stability loss of boom self-propelled cranes during the work on weak load-bearing soils. The fulfilled out theoretical investigations of effort distribution in supports depending upon the angle of a boom pitch (boom extension), the angle of boom rotation in a horizontal plane and the weight of the load to be lifted allowed offering a practical realization of measures for boom self-propelled cranes updating at the expense of the introduction of underlying mechanisms allowing not only the assurance of surface horizontal positioning, but the change of soil bearing capacity (supporting surface). 
 For the determination of the effectiveness of the device offered ensuring a table work on weak load-bearing soils there was developed a procedure for the fulfillment of experimental investigations consisting of two stages. At the first stage there were defined efforts in crane supports depending upon a weight of the load to be lifted and sp-acial boom position. At the second stage there was carried out an estimate of crane support subsidence into soil of different state for basic and updated machines. The investigation results are confirmed with confidence probability of 0.95 by Cochran, Student and Fisher criteria. 
 As a result of experimental investigation carrying out there was defined that the application of an updated design allows increasing self-propelled crane stability by 1.41… 2.27 times.

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.

Stability analysis of mobile cranes and determination of outriggers loading

Purpose The purpose of this paper is to develop mathematical tools that are reliable and easily implementable in computer codes, which address the determination of the outriggers reaction of mobile cranes and the monitoring of the actual stability margin available during lift operations. Design/methodology/approach An algorithm that determines the load transmitted to the ground by a mobile crane with four outriggers has been developed. Static theory of rigid body is adopted for the development of the algorithm and the static indeterminancy, due to the presence of more than three outriggers, is eluded through the adoption of specific hypotheses. An analysis of crane stability is also performed, and a method to monitor the actual stability behavior during lift operations is suggested. Findings A case study is proposed to test the algorithm and outcomes show a good matching with the actual outriggers reaction measured during a test conduct in situ. Two indices are introduced as a measure of the stability margin. Research limitations/implications The method developed accounts only for gravitational forces statically applied. Future works should be addressed to extend the model to the effect of wind and inertial forces. Practical implications This paper supplies a reliable tool to assess, in the design phase of a lifting operation, the compliance between bearing capacity of the ground and loads transmitted by outriggers. The method proposed for the analysis of the stability behavior is suitable for the development of an anti-upset device. Originality/value This study contributes to efforts to increase safety during lifting operations with mobile cranes. The method proposed is applicable to cranes with any geometry of the outriggers pattern and is extensible to a number of outriggers greater than four. Furthermore, the evaluation of the measure in real time of the stability margin, is not affected by the data entered by the crane’s operator with the consequence that human factor does not affect this measure.

Stability Analysis of Tower Crane During Rotational Motion and Influence of Wind

This research deals with the stability of tower cranes operating with full load under the influence of wind in order to determine dynamic loading. The case of crane motion is rotation around vertical axes. The method of analysis is the calculation of the stability conditions, getting results through modeling and simulations and experimental measurements. Rotational motion is usually followed by heavy oscillations mainly caused by load swinging, which acts on boom, mast and other parts. When crane works in an open place, it undergoes additional aerodynamic forces caused by wind that have variable intensity and direction. This occurrence can create problems with stability, load drop or crane overturning. Based on wind force, simulations will be applied in order to find the nature of oscillations, form and extent of forces that can cause instability, and to calculate parameters for stability conditions. Analysis will be done using modeling and simulations with computer application SimWise 4d. Results gained will be used to get conclusions about dynamic behavior, extent of oscillations, design of crane stability and safety during work. They will be presented in graphical form.

Parametric and linear parameter varying modeling and optimization of uncertain crane systems

This research investigates uncertain crane motor system unstructured, structured, and linear parameter varying uncertainty modeling, control, and optimization frameworks. The proposed approaches effectively address the uncertain or time-varying plant components that typically exhibit significant variations under normal physical operational conditions with external influence, implying a complex stabilization and performance synthesis problem with a need for sophisticated quantitative frameworks, suitable for real-time implementations, as compared to traditional proportional-integral-derivative controller implementations. The crane system motor inductor component uncertainty is modeled analytically for the proposed three frameworks by using the uncertain state-space approach and the corresponding Multi-Input Multi-Output Linear Fractional Transformation modeling is used to formulate robust optimization problems for superior tracking performances under operational disturbances. The uncertain crane controller synthesis numerical results clearly indicate the effectiveness of the proposed modeling and optimization frameworks on desired tower crane stability and performance levels.

Stateczność żurawia dla różnych stanów obciążeń i trajektorii przemieszczeń ładunku

Stateczność żurawia dla różnych stanów obciążeń i trajektorii przemieszczeń ładunku

STABILITY CONTROL OF ELEVATING-TRANSFER VEHICLES IN THE CONSTRUCTION

The underground space is widely used in the construction in big cities of the Russian Federation. These works need the use of elevating-transfer vehicles. In this case the requirements of norms and regulations on operating safety should be strictly observed, because their breach often leads to emergency situations and injuries. The organizational and technological solutions when developing the design documentation and executing construction and assembly works should be primarily based on the stability of lifting facilities. The author states the requirements to installation of lifting tackles (cranes). The features of their installation in different operation conditions on construction sites are described. The crane stability depends on many different indicators, which are considered by the author. The calculation algorithms of crane stability are offered.

Reliability Analysis on Anti-Overturning Stability for Truck Crane

To more accurately learn reliability on anti-overturning stability for a truck crane, a parametric multi-body dynamics model is built in a dynamic software environment with overall key parameters as design variables. On this basis, stability criteria of this truck crane are established according to the working conditions and crane dynamics simulation results. After a truncated normal distribution sampling method is given for design variables which will effect on truck crane's stability, the reliability analysis of this truck crane is done via Monte Carlo method. The result indicates that the truck crane's stability reliability is 0.9998 in the most dangerous working condition. Analysis shows that the reliability calculation of truck crane anti-overturning stability is feasible using modern multi-body dynamics and Monte Carlo method, and the results are more accurate than conventional safety factor method.

The Calculation Method of Axial Force in the Calculation of the Boom Tower Crane Stability

The concept of equivalent stiffness and equivalent negative stiffness is introduced in this paper, established the equivalent relationship between the force acting on the middle of variable cross-section column and the force acting on the top of constant cross-section column on boom tower crane lifting plane and slewing plane by the equivalent stiffness law and the equivalent negative stiffness method, The force on the middle of column is converted into the force on the top of column by the equivalent relationship.

Big blue goes down. The Miller Park crane accident

The catastrophic collapse of Big Blue on the Milwaukee Brewers baseball stadium retractable roof project could be the most awesome lift accident of all time. The crane, a Lampson TransiLift III with a 340 ft main boom and a 200 ft jib, was setting a 100 × 180 × 16 ft open truss panel roof section weighing close to 500 tons at a lift height of 230 ft. With 11 diesel engines, 6 miles of wire rope and 1150 ton counter weight, the 2100 ton crane was a massive machine, indeed. The accident occurred during 26 mph average winds with gusts in the mid 30’s. Three ironworker fatalities and hundreds-of-million dollar damages resulted from this mishap. The ensuing litigation pitted co-defendants Mitsubishi Heavy Industries, the crane lessee/operator versus Lampson, the crane designer/builder, on totally disparate theories for cause and origin of the failure. The paper describes the comprehensive engineering analyses undertaken to disprove the Mitsubishi theories of failure as confirmed by jury verdict. Among the topics discussed are: wind tunnel testing, structural analyses of the boom, metallurgy of failed parts from a critical king-pin assembly, and soils engineering work related to ground loads and displacements during the lift. Crucial role of the SAE J1093, 2% design side load criterion and Lampson’s justification for an 85% crawler crane stability criterion are presented.

The Dynamic Stability of Mobile Cranes

Overturning occurs in an unacceptabtably high proportion of accidents to mobile cranes. These are often considered to operate as static machines and empirical factors are used to make allowance for dynamic effects. This paper examines a number of static and dynamic effects that contribute to a reduction in crane stability. It introduces the concept of a ‘stability quotient’ to indicate the ratio of an overturning moment under dynamic conditions to its static equivalent. The results of tests to verify theoretical findings are discussed. A reduction in slewing speeds is one of the principal recommendations.

Cranes in storm winds

In the first part of this paper the theoretical effect of wind gusts on crane stability is examined. It is assumed that the crane is a system with a single degree of freedom and that the wind applies a constant (overturning) moment supplemented by a short duration (gust) moment. It concludes that the approach to crane design adopted in the majority of Codes and Standards which takes a constant wind velocity and a static structural response is acceptable for most cranes. The second part of the paper develops a method, based upon that used in CP3: Ch. V: Pt. 2, for selecting appropriate out-of-service design wind speeds for ‘nomad’ cranes, such as builders' tower cranes, which are used in a variety of locations during their useful life.