Heavy Crane Research Articles

Experimental and Estimation of Flashover Voltage of Outdoor High Voltage Insulators with Silica Filler Based on Grey Wolf Optimizer

Abstract Epoxy is used widely in high voltage outdoor insulator because of its light weight (this avoids the need to use heavy cranes for their handling and installation and this reduces cost), easy handling, easy blending with additives, and having hydrophobicity. This paper focuses on improving epoxy electrical characteristics (flashover voltage) for high voltage outdoor insulator by adding silica filler. Composite of epoxy with silica filler: silica is prepared with 0 %, 10 %, 20 %, 30 % and 40 % weight percentages concentration. The flashover voltage (FOV) is tested under various environmental conditions with different samples lengths. Grey wolf optimizer (GWO) is developed to predict the best optimal value of flashover voltage under various environmental conditions using laboratory measurements of flashover voltage. The obtained results from GWO are compared with experimental measured data. Results showed an improvement with silica concentration at different samples lengths in flashover voltage for composite samples over epoxy without any additions. A comparison between three different conditions showed higher flashover voltage for samples in dry condition than that of samples in (wet, salt wet) conditions.

An innovative concrete-steel structural system for long-span structure allowing a fast and simple erection

In achieving medium-to-long span slab, steel-concrete composite beams may offer an alternative over pre-stressed beams for the so-called disadvantages of the latter; for example the heavy weight of pre-stressed beams makes their handling expansive. However, the use of composite beams by concrete builders is still limited due to the lack of specific tools and skills for on-site erections and the need for a supplementary fire protection. This article presents an innovative steel-concrete moment resisting portal frame that overcomes these difficulties. It is composed of composite tubular columns, and a composite beam made of a U-shape steel profile used as permanent formwork to encase a concrete beam. The steel-concrete duality of the proposed beam allows an erection on site without any weld or bolt by a wise positioning of the construction joints. As only steel elements have to be handled on site, there is no need of heavy cranes. This system has been used to build a research center near Rennes, in France. As it is not covered in present norms, an experimental validation was required. In this paper, a series of full-scale experimental tests that have been performed in order to assess the global and the local behaviour of the frame and its connections are presented. A series of asymmetrical push-out tests were carried out in order to determine the ductility and resistance of shear connectors; one 4-point bending test was made to investigate the resistance under sagging bending moment; and, two tests of the beam-to-column joint were performed in order to validate a strut and tie design model of the joint. Finite element simulations have also been made in order to acquire more information for the development of the analytical models.

Derivation of a new fatigue class for top flange to web junctions of runway beams

In the course of the European standard harmonization the introduction of the Eurocodes in the technical approved area for steel construction led to a significantly more conservative classification regarding fatigue failure, especially for flange to web connections of runway beams in heavy smeltery cranes compared to former design experiences such as from DIN 18800 and DIN 4132. Actually these changes would lead to a doubling of the cross-sectional thicknesses, which e.g. also can result in web plates with extreme thicknesses of 80 mm. Execution as well as monitoring of such flange to web connections using full penetration tee-butt welds are quite critical and could no longer be realized economically.Encouraged by the operators of such constructions and crane installations from the metallurgical industry, the aim was therefore to devise an amendment to the correspondent actual fatigue classification in the Eurocode. The basis for these efforts are crane runway girders designed according to the "old standard" and their damage behaviour for the notch detail "concentrated wheel load" at the upper neck weld. Some of these girders have been in use for decades and usually show no damage for this connection type, if the design is suitable according to previous standards.The investigations were accompanied by numerical simulations. The results are closing the experimental gap that has been existing and that so far has been bridged by experience and interpretation of single test results, justifying a modification of the rules in EN 1993-1-9 Table 8.10.

Accelerated Construction of Short Span Railroad Bridges in Iran

A comparison is made between the three conventional methods used for accelerated bridge construction (ABC) of railroad bridges in Iran: single-piece deck installation by heavy cranes, multisegment deck installation by cranes, and single-piece deck installation by the so-called roll-in or sliding method. Both the safety of the construction and the serviceability of the railway line during the construction process are the main factors influencing the appropriate alternatives. Four railroad bridge construction case studies are demonstrated and compared here. Based on the individual situations, it is shown that the use of the roll-in method, in comparison with installation by crane, can reduce the installation costs significantly, eliminate the fatigue-prone details of the steel connectors, and eliminate the time for concrete casting in conventional multisegment deck installations.

Dynamic Interaction of a Heavy Crane and a Ship in Wave Motion

Dynamic Interaction of a Heavy Crane and a Ship in Wave Motion

Dynamic analysis of a floating wind turbine in wet tows based on multi-body dynamics

In this study, a submerged tension leg platform wind turbine (STLPWT) which can be constructed near the quayside and then wet-towed to the installation site as a unit was proposed. This transportation method will consequently reduce the use of heavy offshore cranes. However, as a high-rise structure, the floating wind turbine may sustain large overturning moments induced by wind, wave, current, and towing force in the transport phase. In order to study the stability of the floating wind turbine and the towline force in wet tows, a numerical model of the towing system including a towboat, towline, and STLPWT was established based on multi-body dynamics. Then, the environmental load effects on the towing stability of the floating wind turbine were investigated. In addition, the comparison of the bollard pull and the height of towing points was performed. The results show that the STLPWT was stable under the rough sea towing condition: a significant wave height of 5 m and a wind speed of 17 m/s. An appropriate bollard pull should be chosen, in practice, as it involves the time and costs of the towing process. In addition, it may be a better choice to set the height of the towing points near the mean sea level to lower the pitch motions of the STLPWT as well as the towline force.

PAL-XFEL 빔라인 허치 구조물 개발

The hutches which are installed in the beamline are largely classified into two, i.e XPP (X-ray pump probe) and CXI (Coherent X-ray image). Laser room is installed on the hutch and provides laser to XPP and CXI simultaneously. And two hutches have heavy crane to install some optics equipments. Safety and reliability of hutch structures should be taken into account for the precise operating of the laser facilities, so vibration analysis is essential to do this. The main purpose of vibration analysis is to install hutch structures with large stiffness. We have changed materials specification several times to install hutch structures having strong stiffness. Now hutch structures were installed and checked vibration status at laser room and XPP hutch. The results of laser table and robot arm satisfy vibration criteria. This paper explains about the design and vibration analysis of hutch structures.

PERFORMANCE BASED COUPLED CFD-FEM ANALYSIS OF 3-BAY HIGH INDUSTRIAL HALL UNDER NATURAL FIRE

In this paper, the main emphasis is put into showing differences between standard fire design of structural elements and performance based approach, that takes into account analysis of structure under natural fire. The exemplary structure is a 3-bay 65,0x110,0 m in plane and 22,0 m high industrial hall with heavy cranes. Because of the significant volume with respect to fire load, there is a low probability that the fully developed fire can occur, nonetheless regarding technological process, a significant local fire could take place and affect the neighbour structure. The most complex approach used in this work is based on coupled CFD-FEM analysis of influence of local fire onto structure.Fire exposure of structural elements is calculated by the coupling scripts, taking into account real heat exposure of section by using adiabatic surface temperature approach.

DOMEX 700W

Abstract Domex 700W is an extra high strength member of the Domex family of cold-forming steels, which are thermomechanically rolled and where all the processing is carefully controlled. The Domex alloys are advanced high-strength steels that reduce the weight of heavy vehicles, trailers, cranes, and containers. The "W" signifies a weather-resistant steel. This datasheet provides information on composition, physical properties, tensile properties, and bend strength as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SA-705. Producer or source: SSAB Swedish Steel Inc..

DOMEX 550W

Abstract Domex 550W is an extra high strength member of the Domex family of cold-forming steels, which are thermomechanically rolled and where all the processing is carefully controlled. The alloy is used in cold formed and welded products. The Domex alloys are advanced high-strength steels that reduce the weight of heavy vehicles, trailers, cranes, and containers. The "W" signifies a weather resistant steel. This datasheet provides information on composition, physical properties, tensile properties, and bend strength as well as fracture toughness. It also includes information on forming, heat treating, and joining. Filing Code: SA-688. Producer or source: SSAB Swedish Steel Inc..

Shore power to ships and offshore plants with flywheel energy storage system

This paper describes a study of major shipyard’s electrical network and simulation of applying flywheel energy storage system on the electrical network at shipyard for shore-power to ships and offshore plants in order to save fuel consumption on engines, mitigate voltage sags, and prevent blackout due to pulsed load and fault, resulting in reduction of air emission into atmosphere. The proposed energy recycling method with FESS (Flywheel Energy Storage System) can be applied for electrical power system design of heavy cranes at shipyards.

Experimental and Numerical Study for the Shaping Formation of SCST Structures by Cable-tensioning

This paper discusses the behaviour characteristics of the shaping formation of Single-Chorded Space Truss (SCST) structures by means of cable-tensioning of bottom chords. The innovative technique is fast and economical and issued in many types of space structures. The small-scale test models presented herein consist of uniform pyramids with multi-directional ball type joints which are erected into their final shape by cable-tensioning. Since the joint behaviour is very significant in studying the shaping of SCST structures, basic tests for beam and pyramidal units were performed. The feasibility of the proposed cable-tensioning technique and the reliability of the established geometric model were confirmed by finite element analysis. The proposed cable-tensioning technique indicates that the behaviour characteristic of joints is very important in the shaping formation of SCST structures. More specifically in situations where heavy cranes are inaccessible, the cable-tensioning construction technique has proven to be an easy and reasonable method compared to conventional construction methods that typically include heavy cranes and scaffolding.

Mobile harbor: structural dynamic response of RORI crane to wave-induced rolling excitation

A new concept sea-floating port called mobile harbor has been introduced, in order to resolve the limitation of current above-ground port facilities against the continuous growth of worldwide marine transportation. One of important subjects in the design of a mobile harbor is to secure the dynamic stability against wave-induced excitation, because a relatively large-scale heavy crane system installed at the top of mobile harbor should load/unload containers at sea under the sea state up to level 3. In this context, this paper addresses a two-step sequential analytical-numerical method for analyzing the structural dynamic response of the mobile harbor crane system to the wave-induced rolling excitation. The rigid ship motion of mobile harbor by wave is analytically solved, and the flexible dynamic response of the crane system by the rigid ship motion is analyzed by the finite element method. The hydrodynamic effect between sea water and mobile harbor is reflected by means of the added moment of inertia.

Shaping and Ultimate Loading of Space Trusses, Shaped by Post-Tensioning Technique

By means of post-tensioning technique, planar space trusses, particularly the single chord space trusses can be formed into curved forms. This novel process of the shape formation results in the architecturally interesting forms with the sufficient structural stability and stiffness, and with the additional advantage of being economical due to eliminating the need to use scaffolding or heavy cranes for their construction. This paper deals with the shape formation and loading tests as well as analyses of the single chord space trusses shaped by post-tensioning technique. To validate analyses and investigate effect of curvature of the shaped models on the results, two models are included; a gently curved dome-shape and a sharply curved barrel-vault. First, shape formation analysis is carried out and next, buckling load of shaped models in loading analyses are determined and findings are compared with the experimental results. Also, effect of the residual stresses of shape formation step on the results of loading analysis is investigated.

Direct Measurement of the Impact of Heavy Loads on Thin Membrane Pavements

This paper presents the results of a field study of the loads imposed by heavy oilfield cranes (with hydraulic suspensions and super single tires) on thin membrane asphalt pavements in Alberta, Canada. Three 150-m test road sections (thin asphalt wearing course, bituminous surface treatment, and granular surface) were built and instrumented for strain at the bottom of the asphalt layer, surface deflection, and subgrade pressures. Temperature and moisture profiles were also measured. Field testing involved controlled speed experiments of standard axle configurations and heavy-axle (12,000-kg) vehicles with and without hydraulic suspensions. Focusing on the hot-mix asphalt section, this paper presents a description of the test road design, instrumentation, and testing plan, followed by some results and findings from two seasons (spring and fall 2005) of testing. Vertical stress in the subgrade, longitudinal interfacial strain, and surface deflection are compared for three vehicle types used in the test. Results from tests show that subgrade stress and interfacial strain are very similar for the standard axle configuration during spring compared with those of the cranes without the dolly during the fall season. It could be argued that on the basis of the pavement response, the cranes could operate during the winter season without the dolly (and thereby increase road safety by removing a long combination vehicle from the traffic stream) without causing substantial long-term deterioration.

DOMEX 1200

Abstract Domex 1200 is a member of the Domex family of cold-forming steels, which are thermomechanically rolled and where all the processing is carefully controlled. The alloy is used in cold-formed and welded products and has a minimum yield strength of 1200 MPa (174 ksi). The Domex alloys are advanced high-strength steels that reduce the weight of heavy vehicles, trailers, cranes, and containers. This datasheet provides information on composition, physical properties, tensile properties, and bend strength as well as fracture toughness. It also includes information on forming, heat treating, and joining. Filing Code: SA-605. Producer or source: SSAB Swedish Steel Inc.

DOMEX 960

Abstract Domex 960 is one fo the Domex family of cold-forming steels, which are thermomechanically rolled and where all the processing is carefully controlled. The alloy is used in cold-formed and welded products and has a minimum yield strength of 960 MPa (140 ksi). The Domex alloys are advanced high-strength steels that reduce the weight of heavy vehicles, trailers, cranes, and containers. This datasheet provides information on composition, physical properties, tensile properties, and bend strength as well as fracture toughness. It also includes information on forming, heat treating, and joining. Filing Code: SA-603. Producer or source: SSAB Swedish Steel Inc.

Reliability of a machine service life prediction in thermal diagnostic test

AbstractReliability of the machine service life determined in a thermal diagnostic test is estimated in this investigation. The time dependence of a thermal diagnostic parameter, and the residual service life (RSL) predicted on its basis, are examined here with the aid of the Monte‐Carlo simulation procedure. The relationships involved are derived from the machine heat balance under two approaches – short term (starting stage) and long term (service time). The diagnostic parameter considered is the temperature change rate during the short‐term period. The constants in its expression are determined from experimental data obtained as an example on the gearboxes of three heavy portal cranes with different service times. The diagnostic parameter–time graph (long‐term approach) derived from the data is used as reference for prediction of the RSL. The reference dependence obtained from theoretical values of the diagnostic parameter, and the RSL calculated from this dependence, were repeatedly varied, with a view to estimating the reliability of the prediction. The uniform and Weibull distributions were used for generating, respectively, the random fluctuations of the reference gearbox temperature and of the diagnostic parameter of the tested one. It is shown that in 95% of the cases the thermal method entails a two‐sided error of at most 3.6%, and for the tested gearbox the discrepancy between the deterministic and simulated averages does not exceed 1.1%. Copyright © 2006 John Wiley & Sons, Ltd.

Failure and reconstruction of a gantry crane ballasted track

The paper deals with the reconstructions that were undertaken to correct multiple ballasted track foundation failures for a heavy gantry crane initially constructed in 1985. A satisfactory design was obtained in 1988 that incorporated geosynthetics.Key words: gantry crane, ballasted track, failure, reconstruction, geosynthetics, soil mechanics, foundation.

Noise exposure profile among heavy equipment operators, associated laborers, and crane operators.

This study, conducted in 1987 and 1988, has made it possible to quantify exposure to noise among heavy equipment operators, associated laborers, and crane operators. The average daily noise exposure was 84 to 99 dBA for heavy equipment, 90 dBA for the laborer, and 74 to 97 dBA for the crane operator. The main sources of noise to which heavy equipment operators are exposed are vehicle engines and the muffler exhaust system, usually located near the operator. The presence of insulated cabs such as those found on power shovels, backhoes, wheel loaders, and graders help reduce noise exposure. The type of tasks carried out by the laborers, the sources of noise from heavy equipment around which they work, and the manual equipment they use determine the noise levels to which such workers are exposed. In the case of crane operators, an insulated cab significantly reduces the operator's exposure to engine noise.