Large Steel Structures Research Articles

Calculation and Application of Steel-Concrete Composite Beams Stiffness Amplified Coefficient

Steel-concrete composite beams have been widely used in the high-rise buildings and large span steel structure. Composite beams effective flange width has been further investigated in domestic, as well as the force and deformation within elastic stage and plastic stage. In this paper, we give out the formula derivation of steel-concrete composite beams stiffness amplified coefficient. Combined with a practical engineering, we analysis the impact of stiffness amplified coefficient on the whole structure by SAP2000 software and compare the results back and forth. In the end, we put forward some suggestions for construction engineers.

Effect of Calcium Addition on the Cast Microstructure of a Kind of HSLA Steel

The rapid development of the large steel structure brings a great opportunity for steelmaking industry. The steel plates not only have the strength and toughness but also can withstand the high energy input welding. Using the calcium oxide of high melting-point and high stability to pin the grain boundaries is an effective method to improve the welding performance of the structure steel. This experiment takes the HSLA steel as the research object, the second phase particles which would not be dissolved or aggregated at high temperature will be expected by means of adding calcium into the steel in the form of Ca-Si alloy. The effect of calcium addition on the cast microstructure of HSLA steel was analysed. The results show that the cast microstructure is mainly consist of lamellar and acicular ferrite, a small amount of pearlite and bainite. Compared with the original steel, there are acicular ferrites presenting in the experimental steel after adding 5 wt% Ca, which are the microstructure that we hope to get. The acicular ferrite will have a positive impact on the mechanical properties of the subsequent rolled steel.

Design and Analysis of the Spiral Staircase in Large Steel Structure

A pillar spiral three floors staircase with no need additional be needed for construction in engineering. Based on this project profiles and steel stairs design standards, the appearance and the form of structure of the stairs be designed. And the spiral staircase’s overall modeling set. Calculated on the strength and deformation be analyzed by finite element analysis software. Provide a reference for other similar projects.

Considerations in selecting laboratory scale test specimens for evaluation of fracture toughness

The assessment of defects in large steel structures requires a trustworthy evaluation of the material’s toughness. This toughness is not only a material property but is also influenced by the loading conditions and geometry; the so-called constraint. The resulting representative value is referred to as the apparent toughness. The evaluation of apparent fracture toughness in a flawed structure is preferentially performed through laboratory scale testing, as full scale tests are both expensive and often challenging to perform. Several laboratory scale test specimens are available, among which a Single Edge Notch Bending specimen, Single Edge Notch Tensile specimen, Double Edge Notch Tensile specimen and Centre Cracked Tensile specimen. Each of these specimens has its own specific constraint. Therefore, the selection of an appropriate test specimen is of primary importance for limiting the conservatism and avoiding potential unconservatism with respect to full scale behaviour. This paper provides a general framework to select an appropriate test specimen based on detailed finite element simulations of both the full scale structure and the laboratory scale test specimens. These finite element calculations allow for a characterization of the crack tip stress fields in both situations. Different theoretical frameworks are available for this characterization; theQ -parameter is considered in this paper. To demonstrate the applicability of this procedure, an example case is presented for circumferentially oriented defects in pressurized pipelines under longitudinal tension. It is concluded that the presented framework allows for efficiently selecting a laboratory scale test specimen, which enables to evaluate the apparent fracture toughness for a given large scale structure. The obtained toughness can thus be incorporated in analytical flaw assessment procedures, reducing the degree of conservatism. This in turn allows an economically effective design.

Key design and construction technology of overall lifting and sliding installation of large tonnage steel structure module

Key design and construction technology of overall lifting and sliding installation of large tonnage steel structure module

ベイズ推定を用いた海洋鋼構造物の犠牲陽極発生電流量同定法の開発

ベイズ推定を用いた海洋鋼構造物の犠牲陽極発生電流量同定法の開発

The Static Analysis about Complicated-Welded on Tubular Rectangle-Joints

Welded rectangular steel tubular joints have been widely used in large span complicated steel structure engineering .With the type of the joints and structural measures complicated, there is no suitable joints theory formula in design specifications. In this paper, two different structural measures types of umbrella steel truss # 8 joints and 68 # joints in a Railway Station are static analysis ,which is by means of finite element software ANSYS and based on the principle of the joints member loading simultaneously. The analysis results show that: in the case of the joints member loading simultaneously, the carrying capacity variation of each member is not uniform coordination; With the different angle between the branch pipe of joints and main pipe, the changes of the degree of stress concentration in the four side surfaces of the member is different. The maximum difference is about 2-fold; compared 68 #joint with 8 # joint, its degree of stress concentration on the overall is small, which prove that structural measures of its domain joints is reasonable.

Laser Welding of Large Scale Stainless Steel Aircraft Structures

In this paper a welding process for large scale stainless steel structures is presented. The process was developed according to the requirements of an aircraft application. Therefore, stringers are welded on a skin sheet in a t-joint configuration. The 0.6 mm thickness parts are welded with a thin disc laser, seam length up to 1920 mm are demonstrated. The welding process causes angular distortions of the skin sheet which are compensated by a subsequent laser straightening process. Based on a model straightening process parameters matching the induced welding distortion are predicted. The process combination is successfully applied to stringer stiffened specimens.

Simulation Study on Construction Process of Complex Spatial Steel Structure Based on the Construction Mechanics

The construction process of the large span spatial steel structure was studied by finite element method and the time-varying mechanics. The construction process of complex spatial frame structure was divided into the installation and dismount supporting phase, and each stage was divided into 15 steps in which mainly simulated and analyzed the whole construction process by "life-death" element. The critical control points of each construction step were identified, the stress state, interval value and the maximum stress in the structure of each construction condition were conformed; rod deformation in construction process was analyzed in construction program. The result showed that the large span spatial steel structure construction scheme was numerical simulated and calculated by the method of finite element analysis and the mechanical state, deformation and safety of building structure were predicted accurately during construction.

QUALITY MONITORING OF LARGE STEEL BUILDINGS USING TERRESTRIAL LIDAR TECHNIQUE

Abstract. Terrestrial LIDAR Technology is used for quality monitoring in construction of large-scale steel buildings to solve the problem of quick and precise inspecting for large steel structure. Point Cloud is acquired fast and of high accuracy with tie-control points that set in different blocks. Feature points are extracted from scan data and compared with its reference points designed to analyze its variation of position and size, which has active guidance meaning for engineering construction. Finally three applications are given to prove the effectiveness of the method proposed.

Design Approach and Analysis Results for Structure Feeders of ITER Magnets

The superconducting magnet system of ITER has ~5,000 tons of cold mass as steel structures to support the gravity and electromagnetic forces. These steel structures need to be maintained at ~4.4 K during magnet operations. The magnet system has three STR (structure) feeders for distribution, monitoring and control of helium to remove heat loads from these large steel structures during cool down and normal operation. One SHe (supercritical helium) circulation pump for flow rate of ~2.7 kg/s, in a closed loop is used only for cooling of structures, and these 3 STR feeders are part of this loop. Each STR feeder has 3 main components: SCVB (structure cooling valve box), CFT (cryostat feed through) and ICF (in-cryostat feeder). Unlike the coil feeders, STR feeders do not have bus bars, current leads & SBB (“S”-bend box), and present some difference in the design approach. The SCVB is placed outside the enclosure of the nuclear radiation shield and hence contains elements needing maintenance like valves and instruments required for diagnosis and operation of the cooling paths. Each SCVB has to accommodate about 20 valves within a limited available space. Some SHe lines will have running length of about 50 m from SCVB to coil structures, but the layout is such that the use of expansion joints can be avoided. The details of the design approach and analysis results will be presented in this paper.

Construction Survey of Main Truss of the National Stadium “Bird's Nest” Project

Construction of large steel structure is the key point of the whole National Stadium “Bird's Nest” project, while construction of main truss is the core of the whole steel structure construction. As connection of main trusses will be carried out overhead, the positioning survey work is quite difficult. This paper introduces the construction survey work of main truss.

Research on Earthquake Load Analysis of Large Structures in Non-Slide Construction

Ocean large steel structures are usually constructed on the slide site, being prone to forming large deformation because of its features such as heavy weight, large bulk and great span. However, the 18 large-scale steel structures of a nickel ore project are need to building on the non-slide foundation, resulting in different settlements of foundation. Moreover, the earthquake load is one of main load of the high-level structure. And the earthquake often happens suddenly and is out of control, with devastating destructive power. To ensure the safety of construction, it’s necessary to analyze the influence of large steel structure responding to the seismic load. This paper expounds the analyzing method on the response of the large steel structure based on non-slide site to the earthquake load. This article has analyzed responses of three-dimensional finite element model to the earthquake load with ANSYS analysis of finite element, such as the stress, deformation analysis, modal analysis and transient dynamic analysis, and assessed the risk of earthquake. This paper provides a feasible and effective analyzed method for researching the response of structure built on non-slide site to the earthquake load, which has important significance for the seismic design of the structure.

Control System Development Based on Arc-Submerging Welder for Flat Fillet Seams

Basing on the original mechanical structure of arc-submerging welder for flat fillet seams, this article designs an arc-submerging welder control system for large steel structures flat fillet seams, such as blast furnaces, oil tanks, and so on, and expatiates on the working principle by circuit designing and testing in detail. This control system has been used greatly in DongYing, DaGang and other construction site for large steel structure.

Pre-Treating Large Steel Structures before Painting

Pre-Treating Large Steel Structures before Painting

Performance-based multi-objective optimization of large steel structures

In recent years, the importance of economical considerations in the field of structures has motivated many researchers to propose new methods for minimizing the initial and life cycle cost of the structures subjected to seismic loading. In this paper, a new framework is presented to solve the performance-based multi-objective optimization problem considering the initial and life cycle cost of large structures. In order to solve this problem, a non-dominated sorting genetic algorithm (NSGA-II) using differential evolution operators is employed to solve the optimization problem, while a specific meta-model is utilized for reducing the number of fitness function evaluations. The required computational time for pushover analysis is decreased by a simple numerical method. The constraints of the optimization problem are based on the FEMA codes. The presented results for application of the proposed framework demonstrate its capability in solving the present complex multi-objective optimization problem.

An Integrated Model for the Fire Safety Analysis of Large Space Buildings

It is now widely recognized that performance-based design provides great advantages over prescriptive codes in that designers are allowed to use fire engineering methods to assess the fire safety of buildings. However, traditionally, performance-based fire safety design is still widely performed separately in specified individual study domains, such as fire engineering and structural engineering etc‥ Although the effects of a real fire have been considered in some structural fire resistant designs and in evacuation simulations, as well as in the mechanical analysis of load-bearing structures, the overall integrated assessment of a whole spatial structure performance is seldom performed. Based on middle-layer structure and component structure technology, this paper presents a new multi-dimensional integrated model and methodology for structural fire safety analysis. The effects of a real fire on structures and evacuation can be simulated through a close coupling of fire dynamics, structural analysis, and evacuation simulation. Based on the model, an integrated system FireSAS, was developed. One gymnasium, a competition venue of the 2008 Beijing Olympic Games, was selected as a study case. The results show that the mechanical responses and behaviours of large space steel structures have complex integrity characteristics as a whole under real fire conditions, and do not suffer merely a local effect. The case demonstrates that the FireSAS system is a useful engineering tool for cost-saving and safe structure design.

The Finite Element Analysis and Optimization for the Steel Structure of Gantry Bucket Wheel Stacker-Reclaimer

Gantry bucket wheel stacker-reclaimer belongs to large complex steel structure. Once it is instability at the working time that will make a large accident. So we have to calculate its strength and stiffness. But its connection and the working condition are very complex. And the size of the model is so large which leads to debase the calculation efficiency. This paper use Pro/E software to create the model. And use Pro/Mechanical to make a finite element analysis. Through the properly simplified the model, we can increase the calculation efficiency. During the calculation result we find that the Pulley yoke, Rigid leg and Flexible leg appear big stress areas. We will give an optimization design for the irrational place and high stress areas. So that to improve the Gantry bucket wheel stacker-reclaimer on-site safety. And provide a certain reference for the subsequent design and improvement.

Dynamic Analysis of Large Steel Structure Truss System

The deformation of the large steel structure truss system, which was subjected to constant loads, variable loads and wind loads, was calculated by using the 3D3S steel structure analysis program. The periods and the vibration mode from the first to the ninth order of the structure were obtained by the earthquake vibration mode period analysis. The dynamic computation of the structure showed that the period difference of the vibration modes is small. The frequencies and the modes of vibration from the first to the ninth order of the same structure mode were calculated by using the ANSYS finite element program. The frequencies and the modes of vibration from the first to the ninth order of the building were obtained by the dynamic analysis of the structure. The dynamic computation of the structure shows that the frequencies difference of the vibration modes is small. The vibration instability is possible for the structure.

Internal Force and Deformation Analysis of Steel Structure Construction Process of Hefei XINQIAO International Airport Terminal

The steel structure engineering of Hefei xinqiao international airport terminal is large span special-shaped steel structure, this paper simulate the construction process and analyze the internal force and deformation. Finite element analysis (FEA) software sap2000 is used to simulate and analyze the steel box girder and tubular truss, the results is used as the basis and guidance of construction monitoring.