steel engineering construction common quality scores and preventive measures

Steel the member tube ball node plus liner, each weld expansion should be 1.5-3.5mm, without the liner, the each welds expansion should 1.0m2.mm, caulking steel nodes, each node in the amount of expansion should 2.0m3.Omm .. Steel Ruler sure unanimous Proofing and contemplate measure change negative.

Assembled or pre-assembled the assembly unit should operate on the in chronological size like, do not grasp the size chosen .. unit construction deflection happens in the steel structure folded normal there should be remaining just bracket bracket mounted on the screw steel engineering k to mobilize the steel structure deflection. basis for the steel structure type, size, and practice conditions, installation operation are appropriate to mobilize, so that the deflection value is less than the design values ​​of deflection Steel Components production grid steel structure construction process


The steel structure is damaged, we want instant instant solution, steel grid introduced steel structure damaged main factors: a change in the steel structure carrying capacity by load changes, extended service, rules and regulations; 2) components due accident deformation, distortion, disability, depression, resulting in the member section weaken rod warp connect cracking on; 3) caused by the temperature difference between the role of the member or connection deformation, cracking and warping; 4) due to chemical substances erosion corrosion and electrochemical corrosion of the steel structure weakened member section; 5) steel engineering  violations include mistakes in the design, production, construction and service midterm use and operation. Double-sided submerged arc longitudinally welded pipes steel structure the application of quality control of large span steel structure cable-membrane structure

steel structure warehouse roof truss construction safety measures

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China steel structure the altitude assembly method according to the structure type and construction conditions

The overall installation method or altitude slip method to install steel truss installed altitude assembled, assembled bracket position in the design and erection of the crane to the grid component sub-parts (or block) hanged to the design of the air position bracket assembly. This method is sometimes no large lifting equipment, but the large amount of assembled bracket, aerial work. Strength bolts connecting the steel truss or bolted spherical joints made of steel pipe truss with China steel structure is more appropriate, there are still some of the construction of steel grid method has been applied

Overall installation method is assembled into the ground on the first grid as a whole, and then use the lifting equipment to enhance the overall design position be fixed. This construction method does not need tall assembled bracket, aerial work less easy to ensure the quality of the welding, lifting large lifting equipment, technology is more complex. Therefore, the steel ball node grid (especially the three more rods to the grid and other grid) is more appropriate. Depending on the equipment used, the overall installation method is divided into multi-machine method lift crane, pull the lever to enhance law jack enhance jacking up method.

This method is used for height and weight are not large, the small grid structure. Prior to installation in the ground grid the the dislocation assembly jobs (ie, the assembled position with the mounting axis shifted by a certain distance, to avoid pillars position). Crane (mostly crawler cranes, mobile cranes) assembled good grid as a whole up to the top of the column above, in the shift of the air to fall into place fixed. In order to prevent the grid to enhance the overall collide with pillars the stagger distance depends on the grid to enhance the clear distance between the grid with columns or pillars corbel process, shall not be less than 10 ~ l5cm grid assembly to consider convenience and the air is displaced to facilitate the work of the crane. Required consultation and design unit, part of the edge of the space truss rod pieces left to grid upgrade after welding, or change some of the impact grid to enhance the pillars

After the processing of the metal structure factory, steel truss, single plane truss or three-dimensional truss makes up a small unit transported to the site, site assembly that is in the assembled position of the small unit the truss makes up the entire grid. The grid assembled the key, is to control the size of the axis of the bearing of a good grid framework (pre-amp welding shrinkage amount) and bagging requirements.

Grid welding sphere with steel pipe welding. General strength butt welding, for safety reasons, the increase in the butt at 6 ~ 8mm fillet weld welding. Wall thickness greater than 4mm weldment groove interface should be made. For the uniform and steel pipe butt weld length slightly adjustable, plus casing. The first assembly mounted on the bottom chord afterloading diagonal web members, to be between two truss steel pipe all placed and correction, and then gradually root welded steel pipes such small grid multi-purpose four-crawler up vertical machine ( or car tire crane) lift crane, also with two crawler cranes, or a lever lifting.

If the smaller grid weight, or four cranes lifting capacity to meet the demand should be four cranes arranged in both side of the grid, so as long as four crane slewing the requirements to complete the grid air shift, multi-machine The key is to lift crane a crane China steel structure or some cranes will overload the grid torsion weld cracking. For this reason, before lifting to be measured most crane lifting speed, in order to grasp when lifting. When the grid lift crane to about 30cm higher than the top of the column elevation air shift, move the grid above the top of the column. Grid settled down for the grid produced midline accurately capitals midline agreement prior the grid four corners of each tied to a wire rope, using inverted chain in place on the line

The arrangement of the cable wind rope should enable multi uprooted rod integrally connected with each other, in order to increase the overall stability. The Each uprooted rod at least 6 wind cable rope, the wind cable rope according to the wind load, hoists, pull lever skew, wind cable rope initial stress load, calculated according to the most adverse circumstances combined select. Ground anchors also need to be calculated and determined.

steel pergolas process jingta

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Fireproof coatings use of countermeasures

The countermeasures problems in the use of fireproof coatings
(A) to strengthen publicity and education to enhance their understanding. Steel structure engineering fire hazard causes are many, but a very important reason for thinking and understanding is steel structurenot in place, contempt fire prevention of the illegal construction of luck.The fire department should make use of newspapers, radio, flyers, and other forms of extensive publicity on fire prevention, organizational design, construction units, the training of fire codes and laws and regulations to improve the level of business theory and law enforcement abiding sense of design, construction personnel. Conditional can also take advantage of the actual case of fire, visits to the scene of the fire; take advantage of the news media and public disclosure of fire losses and casualties; convened fire responsibility to publicly address the General Assembly, so deeply rooted awareness of fire safety in the entire society everyone. 

(B) the correct selection of a variety of fire-resistant coating. A wide variety of fire retardant coatings market, its fire performance are not the same. Therefore, must be full investigation of the role of fire retardant paint varieties grasp its performance, and in accordance with the substrate coating normal use conditions and fire environmental conditions, such as the right choice varieties of fire-resistant coating. Thin, ultra-thin or thick fire retardant paints can not be indiscriminately on for all steel structure fire protection, must be in accordance with the building fire risk, environmental conditions, production technology, value protection aspects to be taken into account, truly fireproof paint fire performance.
(C) strengthen the supervision and management, good production and sales shut. Fire resistance and physical and chemical properties of test report products sold must be qualified by the national testing organizations in order to sell the factory, and shall be accompanied by the manual, indicating the technical steel structureperformance, manufacturing batch number, storage period, the scope of application. Fire supervision departments respond to each batch of fire-resistant coating to the factory quality sampling and testing its packaging, labels, indicating compliance with the requirements. All operating units of the fire retardant coating, purchase required to contact the manufacturer for product brochures and other information provided to the user in the sales brochures and other information, and the implementation of the operating systems listed, marked with the manufacturer of the product, technical performance, product testing organizations, the scope content. The fire supervision departments should track supervision, regular or irregular spot checks of product quality, mastery of the marketing staff expertise and after-sales service. Violation of the provisions of the production of substandard products, endangering public safety by or unlicensed, unlicensed operators, according to the law strictly, sales of fake and shoddy products, in conjunction with the industry and commerce, quality supervision and other relevant departments to resolutely crack down on the majority of maintenance users and the interests of the masses. 

(D) to strengthen the supervision of the construction site, testing organizations. Book issued an audit opinion, the fire department should expressly require the the fireproof coating construction unit shall have the appropriate the construction qualification to undertake the project, at the same time to track the construction site supervision services. Such as before brush fire retardant coating, require the construction unit first surface rust and rust treatment is determined according to the requirement, the steel surface debris should be cleaned and the gap junction applications of fire retardant paint or other fireproof material to fill the blocking level before construction. Should maintain good ventilation, rainy days or when the surface of the steel members condensation, unfit for the job. Because of the rapid construction of fire-resistant coating, strengthen the supervision and inspection of the construction site, it is extremely important. Check through the construction site, you can master the basic situation of the construction team and the progress of the project, the quality is good or bad, whether the product is qualified. Also only field inspection and supervision, to discover hidden promptly rectification hidden to avoid unnecessary losses. In addition, to strengthen the detection units of firefighting agency management efforts, and correctly guide industry self-awareness, strict testing specifications and requirements, to give the corresponding penalties for a false report or larger error detection unit, until the abolition of their qualifications.
(E) strict acceptance criteria to ensure that the quality of the project. Fire department in the construction unit to apply for acceptance requirements before the first request to provide intermediary testing organizations test report and construction records, including the records of the hidden works, at the same time the fire department in the site acceptance process to grasp the following requirements of the classification and acceptance: The coated thin fireproof coatings to comply with the following requirements: 1 between the coating and the steel substrate and coating firmly bonded between, such as delamination, hollowing; 2, coating thickness to meet fire resistance design requirements; 3, the appearance of the coating to be smooth, clear contours, color uniformity, no obvious depression, chalking, loose laitance, mastoid have been removedsteel structure from any individual cracks, its width should not be greater than 0.5mm. Thick coating fireproof coatings to meet the following requirements: 1, between the coating and the steel substrate and coating bonded firmly and completely closed, such as delamination, hollowing; 2, coating thickness of 80 area% (inclusive) to meet the design requirements for fire resistance, and the thickness of the thinnest should not be less than 85% of the design thickness; 3, the appearance of the coating should be smooth, without significant depression, chalking, loose laitance , have been removed from any individual cracks mastoid, its width should not be greater than 1mm. Acceptance When you encounter one of the following circumstances, should check whether its coating steel components connected to steel mesh, to ensure a solid coating: 1, withstand shock and vibration beam; 2, the design coating thickness is greater than when 40mm; 3, sticky lacquer strength is less than a coating of 0.05Mpa; 4, the web height of the beam greater than 1.5m.

New technology for steel the high corrosion coating rust

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The Comparison of the Series of the light steel structure workshop

Light steel structure workshop clear and simple recognition of the community. Analysis of the current situation, the construction of the building of the domestic and foreign enterprises in building performance gap between the following three aspects: (a) In essence, the gap in the architectural design concept, the architectural design of light steel still performs the existing various building codes, and concrete building is no essential difference. Its architectural concept is the use of special material, indeed a different place with concrete, and thus make the building performance of a variety of differences
1, the integration of building structural design is the design of concrete building design according to the structure after the first architectural design concept design, light steel building due to its special materials and advanced design software has enabled the design process to achieve the building structure one design, architectural design is completed with the structural design is completed at the same time. Light steel enterprises abroad are to follow such a philosophy, most enterprises are still running the design principles of concrete construction. Building design according to the design of concrete building design, structural design, on the one hand that it would demonstrate its architectural style, on the other hand, the destruction of a light steel building unique architectural features. For example, the light steel structure can achieve large span concrete structure is difficult to achieve. As architectural design engineers do not understand this situation, therefore, the design of the building may have been a small span of the building, which could lose the building has a grand and imposing large span building opportunities. This is mainly due to the current state-of-the-art design software causes many domestic and Design Institute. With the popularity of various state-of-the-art steel structure design software in the future, this problem will be solved satisfactorily.
Containment system, with the main structure design integration basic practices of Chinese enterprises in this regard is that the design of the main structure, the maintenance system designed separately, while the the foreign general practice is a unified design, even some companies still perform construction modulus made to ensure the accuracy of building the overall installation. For example, between the two uprights install interior wall panels, interior wall panels from the left column, row by the former practices, the board is a high rib to the right column are high rib. In fact, This indicates that by the practice of the former can not guarantee the accuracy of the installation, while the latter can ensure the accuracy of the installation.
Accessories system designed with the overall building systems integration building designed by the foreign enterprises in the installation, when the basic guarantee for the end of the installation, no extra accessories on the ground, there is no lack architectural accessories. The majority of domestic enterprises or small accessories or accessories. This is because the non-uniform results of the the accessory system design and the design of the entire building systems. Building performance can also be affected. Of course, there is also a standardized accessories. (B) Construction manifestations gap light steel building construction performance are mainly the following four characteristics that scale, lines, colors, and change. In these four areas, we are different gaps.
1, the construction scale: light steel structure workshop designed by foreign enterprises in building scale performance, the performance was very good, especially the a ridge Shuangbo or with parapet large span light steel building, has a grand building momentum. This building scale performance works of architectural styles, from the hands of domestic enterprises, yet rare

On-site fabrication and installation of steel structure color steel sandwich panel

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light steel structure Engineering and the Built Environment

Combining environmental building the second session of the National light steel structure Construction Technology Seminar held recently in Guangzhou, Housing and Urban-Rural Development Ministry of Science and Technology Division, Deputy Director Han Aixing at the meeting, the steel structure is also combined with the built environment. Hanai Xing pointed out, along with China's reform and opening up and economic and social development, while the development of the cause of building, steel structure has also been a lot of development, this seminar marks the steel structure from the earliest discussions not to the development of steel structure to now how to develop a steel structure, even in the steel structure of the research design stage into the construction phase.

Steel structure construction technology compared with other concrete technology, a lot of design technology is not important, relatively speaking, materials, theory in the design of the research phase is good to engage in the construction aspects with concrete and other terms, the construction little more difficulty and the problems encountered are a lot of aspects to re-examine the new understanding, especially since the recent situation of many of the new structure in the country generally build up a lot of new construction. Toward highly integrated building technology, many industries need a lot of technical, need to combine, under the present conditions, and energy conservation, the environment, the combination of this seminar is from more structural technology, construction and installation, welding, etc. discuss, which is the most basic and fundamental essence, throughout construction science, construction environment far not to these areas, the steel structure is also combined with the built environment. Hanai Xing pointed out that, in recent years, the domestic many strange building or steel building, mechanics, construction connection welding technology has made a breakthrough, but also had a certain impact on society and the environment,

Several light steel structure projects, environmental concept would think that the people living in the building work and live is inappropriate, not just from an environmental sunshine, wind, or my heart are inappropriate role. Some buildings in which to live will get sick. The environment created, this is a big premise can not be changed. According to reports, the steel structure construction technology exchange, is to sum up the experiences and lessons of the technical problems in the past major projects in the construction process, to discuss the steel structure project currently under construction, new materials, manufacturing processes, the installation program, application technology research, face new issues and new challenges, learn new construction techniques and construction methods.

The Assembly election held in Guangzhou, Guangzhou has built and are building a very influential group of international and domestic construction steel structure projects, such as the new Baiyun International Airport, Guangzhou New TV Tower, Pearl River New Town West Tower, Guangzhou Opera House, Pazhou International Conference Center, and so on. Some of these projects represents not only the construction of the highest level of China's construction sector, as well as the emerging space structure stadiums, and some are under construction engineering allows delegates to learn more intuitive design of steel structures and construction problems.

The VSR future and its effect-jingta

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Superfinishing surface quality influencing factors and control measures

Keywords: machinery and equipment parts surface quality control measures influencing factors
With the Superfinishing development of China's science and technology, to a large extent, promote the development of the machining industry, machining industry occupies a larger proportion of the market economy. Performance and service life of machinery and equipment, is an important criterion to measure the production levels of the corporate machinery, and the operating efficiency of the machinery and equipment by the influence of mechanical parts, if the quality does not meet the requirements of mechanical parts, when told running of the machinery and equipment, on will lead to lower efficiency equipment noise problem is serious, and even cause serious security incidents, therefore, to ensure the quality of the surface of the part, while the emphasis on the parts to use performance.

Analysis of factors that affect the surface quality of the parts
(A) production equipment factors
Mechanical parts in the production process, production equipment has a significant impact on the quality of products. In general, the production process of the mechanical parts need to go through the grinding process, the conduct of these production processes must be done by a professional production equipment support. However, due to the production equipment of the mechanical parts processing enterprises in China compared to the production line there is a big gap between the more developed countries, the production equipment backward production equipment accuracy and equipment productivity enough to affect the overall quality of the machine parts. For example, in the production process, the lack of stability of production equipment, there will be more substantial vibration problems in the production process of sanctification, so that the parts of the surface chatter marks, increases the surface roughness, thus deteriorating the quality of the machined surface. have serious quality problems.

(B) production of technical factors
Superfinishing parts processing, the production technology of choice, also determines the surface quality of mechanical parts. For example, under the same conditions, the carbide tool surface roughness of the machined parts to be significantly lower than the high-speed steel cutting tools, diamond, cubic boron nitride cutting tools production effect is more superior to carbide. However, in the actual production process, the production of parts of the material should be based on specific selection, otherwise, also the quality of the parts of the surface will have some impact. For example, the affinity of the diamond with iron-group material, making the processing of iron-group material parts are not suitable selection of diamond tools, or the production quality will be seriously affected. Meanwhile, in the production and processing of brittle material parts, the chips will appear in particulate form, if in the process of cutting swarf occurs problems such as chipping, causes parts of the surface more rough, and therefore, during the production before machining, must be considering the features and characteristics of the material, and to choose the production technology.

(3) other factors
In the process of mechanical equipment, will cause a certain impact on the quality of the surface of the mechanical parts, the main influencing factors including abrasion resistance, fatigue strength, and corrosion resistance, etc., if the mechanical parts of the property can not meet the conditions of use of the device and the construction environment, will be a serious impact on the life of the equipment and the use of mechanical effect. Therefore, in the actual production process, it must be comprehensive consideration of the relevant properties of machinery parts, machine machining surface quality and resistance, to ensure the normal operation of mechanical equipment.

Machining surface quality control measures
(A) to strengthen the introduction of advanced equipment
Add some product processing equipment, has a very large impact on the surface quality of the mechanical parts, therefore, strengthen the introduction of advanced production equipment, improve the overall performance of the production equipment, effective way to control the quality of the machined surface. With the continuous development of China's science and technology, the performance of production equipment and run effect gradually enhanced, therefore, must be to strengthen the machined surface quality control, to ensure that the use of machinery and equipment performance. Production business process, you should pay attention to the introduction and application of production equipment, improve the process parameters to reduce surface roughness to ensure the market competitiveness of the machinery and equipment.

(2) emphasize the machining method \
At present, it is possible to reduce the processing method of machining surface roughness ultra-precision cutting and ground roughness grinding method, and is responsible for the final step processing of ultra precision machining, grinding technology. Ultra-precision machining during mechanical parts processing, there are generally three forms of exercise, low-speed rotary movement of the workpiece, the grinding head axial movement as well as Whetstone three reciprocating vibration, three different running form, form is not repeated mechanical workpiece surface trajectory, to enhance the degree of smoothness of the surface of the workpiece. Ultra-precision machining process of cutting and grinding with grinding there is a big difference between the the rough workpiece production of ultra-precision machining, the workpiece surface wore off, the whole contact area will greatly increase the pressure also will swordsman, the workpiece will conjunction to form a layer of film between Whetstone Whetstone with the workpiece will not again be direct contact.
(C) improve the surface mechanical properties

Another method to improve the machining surface quality is reasonable improvement in the process, the physical and mechanical properties on the surface of the workpiece and to change the processing method, so as to achieve the purpose of increasing the surface quality of. Before conducting machining, we must first develop a reasonable processing process in order to guarantee the quality of the workpiece machining, the unloading surface quality processing to provide a reasonable scientific basis. In the process, you must select a reasonable cutting parameters reasonable cutting parameters is the suppression cutting BUE important factors can effectively reduce the residual processing area of ​​the height, to ensure that the workpiece surface smoothness of. Machining depth of cut and feed rate also has a direct impact on machining surface quality. Appropriate to reduce the main the declination and vice declination angle in the case of a certain amount of feed, and are able to effectively reduce the workpiece surface roughness. In addition, in the machining process, it is should be noted that to select the appropriate cutting fluid, to improve the coefficient of friction between the machining tool with the workpiece, effectively reduce the interaction between the temperature of the tool with the workpiece in the cutting work, so that the degree of wear of the workpiece to greatly reduce, to ensure the quality of the machined surface.
Summary:

Machined surface quality of the Superfinishing of the use of machinery and equipment and production efficiency has an important impact on machining surface quality problems, will result in greatly reduce the stability of the machinery and equipment, the use of performance greatly reduced, the noise problem is obvious, and even cause serious industrial accidents, therefore, must be emphasis on mechanical processing sectors, to take reasonable measures to improve the smoothness of the surface of the part to improve the effect of the use of parts. The same time, the actual production process, we must attach importance to the properties of the mechanical parts, such as the degree of abrasion resistance, corrosion resistance, fatigue resistance, for the use of the environment and conditions of use of the equipment, make full detection work to extend the use of mechanical products life, to ensure the healthy development of the machining industry.
Technology and the principle of Stress Detector voltage tester:http://steelprofileexport.blogspot.com/2012/12/technology-and-principle-of-stress.html

Vibration Stress Relief equipment on the benefits of casting, welding and other components

Casting, welding, forging, machining, etc. during the manufacturing process, the workpiece internally generated residual stress. The presence of residual stress will inevitably lead to the deformation of the workpiece, cracking, and seriously affect the stability of the size of the workpiece, reduce the fatigue life of the workpiece. The traditional aging treatment is a natural aging and thermal aging. Natural aging long production cycle, the accumulation of capital, and the space occupied by: thermal aging and annealing temperature, and cooling time speed, aging furnace temperature difference and other factors, and huge investment. With the development of science and technology, increasing aging VSR due to aging effects of the dimensional stability of the workpiece, economical and practical, less investment, energy conservation obvious advantages, gradually replaced the traditional natural aging and thermal aging more and more widely used in practice.

Vibration Stress Relief from percussion aging. The workpiece through special equipment to generate the resonance in the natural frequency, so that the the cyclical dynamic stress and the residual stress is superimposed, so that the workpiece partially plastically deformed and release stress. Thereby reducing and averaging Chemical member internal residual stress, and the accuracy of the workpiece size to achieve stability. The vibration processing technology, also known as do vibration to eliminate stress, in the country, also known as VSR. It will have a the eccentric weights motor system (called the exciter) placed in the member, and the member is supported with rubber mats and elastic objects, as shown in Figure 2.1. Starter motor and adjust its speed by the controller, so that the member is in a resonance state. After about 20 to 30 minutes of vibration treatment can achieve the purpose of adjusting the residual stress. Vibration test systems and strain (or stress) test system, Vibration Stress Relief process used to measure amplitude-frequency characteristic curve monitoring the amplitude of the dynamic stress changes. The vibration treatment member equipment layout can be seen, to adjust the residual stress with a vibration technology is very simple and feasible.

The residual stress after the vibration treatment member can be eliminated from 40% to 50% high tensile stress area, left glazed winter eliminate larger than the low stress zone. Therefore can improve the strength and fatigue life, reduce stress corrosion, prevent or reduce the incidence of microscopic cracks caused due to the heat treatment, welding process, which advances in the ability of member resistance to deformation, stable members of precision, progressive mechanical quality.
steel Profile export
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China steel structure steel structure construction technology

New construction technology center &nbsp twenty-sixth World University Games held in Shenzhen in August next year.As the "bird's nest", undertake the Universiade opening and closing ceremonies and the main event of Shenzhen Universiade stadium also has attracted a lot of attention.The builders in the engineering project, process difficult, complex construction process, refine on, worked tirelessly, compose the venue construction gorgeous.The first rotary slip new technique Universiade center "a museum" is the 2011 World University Games Stadium, a total investment of 4100000000 yuan, in 2007 August start working.Among them, the main stadium is currently the largest stadium under construction, will be held at the Universiade opening and the final China steel structure track.Universiade stadium complex structure, the internal membrane of the steel roof system,


Adopted in the steel roof of "saddle single-layer folded-plane spatial grid structure steel structure", the highest point 51.3 m, Max suspended 68.4 meters, the entire structure is novel and unique, and the gymnasium, swimming pool together constitute three of  "crystal stone".Engineering in the construction is faced with a series of world-class technical problems, both in quality, construction and technical aspects, difficult as Beijing Olympic Stadium "bird's nest".The special is the first in the domestic large scale use of cast steel node and super thick casting steel pipe, this novel form of steel structure, so that the Universiade Center steel quantity only 180000 tons, equivalent to the "bird's nest" quantity of steel 40%.Due to the structure of novel, complex shape, design for cast steel component quality requirements are very high, the current domestic only a few items used, no national standards and norms, the volume is big, the casting is difficult, it is rare.China steel structure In order to ensure the Universiade Center steel structure construction, project uses new technology.Reportedly, the international large-scale buildings using the rotation slip new technology for the domestic first, on the 95 day was completed inside the stadium in 5800 tons of steel structure construction, achieved domestic Stadium Steel Structure Construction of new record.Universiade Sport Center Stadium steel structure project has won the 2009 prize of China steel structure and the first batch of Guangdong Province gold "steel structure, steel Award", in the construction has not yet completed cases, it has become a benchmark for National Stadium construction.A born beauty of fair-faced concrete Dayun center uses a lot of abroad in the construction industry,





Especially the developed countries such as Japan, Germany, the universal application of the fair-faced concrete technology.This technology has the advantages of durability, short construction period, less pollution, lower maintenance cost advantages, but for the template system, supporting structure, concrete pouring and curing construction technique, strict requirements.Universiade stadium stands for clear water concrete prefabricated plate, surface density, beautiful appearance, few attended Beijing Olympic Games venue construction and supervision of the total package units, generally reflect than "China steel structure's nest" effect is ideal.It is a primary color, reduce pollution, repair costs are relatively low.Universiade center's main designers, German GMP international architectural design limited company president von Gkan visited the Universiade center, Dayun Center for fair-faced concrete effect is very satisfactory, said it was the best he has seen the effect of a clear water concrete, and said to the Chinese enterprise technology to germany.In addition, in order to achieve unique crystal stone effect, Dayun center was designed in 20 different light distribution, and use of the world's leading 6 core patented technology independent control system, can be synchronized control 23880 sets of intelligent lighting, a total of 88350 independent control unit, and can realize 365 days a year to automatic operation and monitoring of.All fixtures are mounted on steel structure part of the main beam and secondary beam, realize the lamps and trough concealed, completely eliminates the significant optical, constitutes a beautiful silhouette effect.
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Superfinishingin the production and Application

Vibration Stress Relief in the market breakthrough in recent decades, vibration aging equipment processing research and application, in our country has achieved rapid development.During this period, with many domestic units together, in the mechanism of vibration aging equipment and applications, has achieved breakthrough results, made our country about vibration aging treatment technology of the national industry standards, to guide the application of the technology and equipment of the production progress, promoted the technology in machinery industry wide application.Vibration aging originated very early, in the last century fifty's, along with the development of modern science and technology, the vibration theory, the test technology and the excitation vibration aging equipment all gets rapid development.So that, in a workpiece resonance frequency of vibration, the vibration can shorten the processing time, eliminate stress and stability precision is better, also the least energy consumption.At the same time, there is a corresponding vibration equipment.This new type of vibration aging process and equipment appearance, immediately by the close attention of all countries, rapidly applied in production practice.As a result of this technology is mature with each passing day, vibration and control improving equipment, vibration aging has been for more than 10 industries are widely used in developed countries.Vibration aging usually only half an hour, electricity and a few yuan the cost limitation, can achieve the aging effect, but also can handle whenever and wherever possible, neither reduce the hardness, and no dust pollution and oxidation skin, it is the heat treatment and natural aging incomparable, known as desired without the costs of aging technology.Vibration aging equipment and processing technology and wide application of the technology have been found and develop.


Vibration Stress Relief in the production of the application of vibration aging equipment with his application approved by the majority of users, has gradually developed, the utilization of equipment, in production has played a great role in promoting, he can be used to stabilize the component deformation, improves the capacity of deformation resistance, improve component size precision at the same time, can effectively reduce and average residual stress, increase the working strength and fatigue life.Vibration aging equipment can also prevent the member in use in the crack.Vibration stress relief technology in relative machinery industry application is very extensive, no matter whether the object has multiple, can be used for handling vibration aging equipment.As long as the basis of structure type selection component vibration parameters and device, can achieve the purpose of eliminating the residual stress.But, even so, obviously, the equipment is still has its limitations.This is due to vibration ageing device performance limitations of the results.At present domestic and foreign production of vibration ageing device, its frequency range below 200Hz, long, wide, if component high ratio close to 1, and the stiffness of the structure is large, it may cause the component natural frequencies over Vibration Stress Relief use frequency range and no resonance.In this case, it must be used in low frequency and large exciting force technology or modular clamping method to reduce the frequency of.To make a long story short, vibration aging equipment and other large parts processing also has been widely applied, because he is a simple, efficient, energy saving, environmental protection and efficient advanced technology, without the size, weight, structure and space limitations, it is worth of application and promotion.

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Construction Engineering durability in several categories

Ministry of Construction Engineering durability classification, but according to the design life span and safety classification reliability design of uniform standards, in accordance with the building structure, "the General Provisions:'s design life of the structure shall be in accordance with Table 1.0.5 using. 15 temporary structures in Table 1.0.5 design life span of classification categories designed useful life (years) sample 225 easy replacement of structural members 350 ordinary houses and structures 4100 monuments and especially important architectural structure building structure design, should be based on the structural damage the seriousness of the possible consequences (endangering human life, resulting in economic losses, social impact, etc.), the use of different levels of security. The division of the structural safety level should be consistent with the requirements of Table 1.0.8 Table 1.0.8 the security level of the building structure level of security is not serious destruction of a very severe consequences for the type of building housing two serious general housing three secondary Note special buildings housing its security level should be determined according to the specific circumstances of a separate; 2 foundation design level of security and the security level of the building structure, design seismic requirements shall also comply with the provisions of the existing national norms.

Perfect interpretation of the B & R control technology in metal processing machinery

Introduction symbol of reliability and durability - Kaltenbach. Power saws and band saws Kaltenbach company's main products, widely used in metal processing machinery, and give high marks for the metal industry expert in the field of well-known, the type of metal processing machinery normally used B & R ( B & R), automatic control technology, because the B & R innovative concept for all of this possible. "The key factor when we choose B & R (B & R) B & R has many advantages such as rich in unique applications, to help customers design the best solution strength" Kaltenbach indicated that the company, electrical design manager Gerhard Strobel said the case . Kaltenbach pursuit of high-quality and high reliability of the product, rather than blindly follow the technology trend to research and development of our products; thus supplier expectations with many years of experience in product development is to provide customers with innovative products. "This, of course, also include an excellent value for money, it is very important for the continuous production machinery manufacturers. "Gerhard Strobel adds. In 1996, German suppliers interrupt supply control system, Kaltenbach decided to replace the supplier. The twists and turns of the past after we choose the control system are always not satisfactory, the vendor can not provide supporting standard accessories such as analog I / O and axis positioning card project, cause we can not establish standards for clients such as can not connect rotary encoder such situations will occur. "Gerhard Strobel recalls. In addition, the suppliers only provide a the expensive single site license. Obviously, we must as soon as possible to solve the problem of the control system. 120,000 Kaltenbach manufacturing machines being used around the world. Faced with such a large number of the replacement system becomes extremely arduous. Due to the the rich metalworking manufacturers product categories and different, this step is to Maide very difficult. The Kaltenbach total of 450 employees, professional R & D and manufacturing of steel and aluminum power saw, band saw, and light steel keel processing system, sheet metal processing equipment, as well as punch and cutting system. Requirements of the high standard of the machine based on the material being processed Kaltenbach indicated that specifications and diverse products is able to provide customers with the best solution: separate production line can have a variety of designs, such as from a semi-automatic saw machines to high-performance full The automation Saw. The now control system must be able to meet the diverse needs of the various types of products. Gerhard Strobel explains, "We use six different types of CPU-other components, such as different I / O configuration, and so the model is also very rich. A fresh start - a trusted B & R control technology "our current major integrated Motorola / Freescale processor-based PLC. Currently, we are for the controller to replace the Intel processor." B & R a new generation of PCC X20 CPU based on Intel technology. "The reason we have a keen interest in the X20 system is because of its excellent cost-effective and high-performance rich combination --- small CPU unexpected performance --- modular structure of the system are able to provide more for our machinery to provide strong support. Kaltenbach indicated that companies like Power Panel as the semi-automated system HMI controllers and industrial PCs combine the structure of complex processing machinery, automation systems,

Highway communications, monitoring, collect fees system lightning protection solutions

One, overview of lightning disaster is a "United Nations International Disaster ten years" published in ten of the most serious natural disasters.The latest statistics show that, the lightning caused by natural disasters loss has risen to third.The United States ranked among the top 1000 enterprises, the average every year due to a lightning strike is a loss of $200000 a year, China, caused by lightning casualties nearly 10 thousand people, lightning caused property damage estimated at 50~100 billion yuan.Guangdong Guangdong Province at present average annual thunderstorm days nearly 90 days, frequent rate ranked second in the nation, but due to a higher degree of modernization, the losses caused by the lightning stroke lists the whole nation the first.A microelectronic communication network equipment located in various buildings, due to lightning induction caused by indoor information system microelectronic equipment damage significantly increased the likelihood of each year, all kinds of lightning events proved repeatedly: conventional building design and installation of lightning protection device and can not effectively prevent lightning induction, electromagnetic pulse, static electricity and lightning wave intrusion on the communication system and computer network information system the harm caused by.Highway two, the comprehensive lightning protection design scheme based on comprehensive lightning protection in highway design mainly adopts the following standards, for a time reference.In 1, GB50057-94 "design code for lightning protection of buildings" 2, GB50343-2004 "of building electronic information system." "3, IEC61024" IEC61312 "4 building lightning protection, protection against lightning electromagnetic impulse" 5, GB50174-93 "code for design of electronic computer room" three, high speed road building lightning protection measures in 1, monitoring center building in general set in the control and management of freeway access terminal or central position of the region.Due to the surrounding terrain relatively open, floor is in commonly six above, height more than 20m and the roof is also provided with various types of communications antennas, some still frame is provided with a tower, these are the important objectives of lightning.The building has a large number of real-time operation of the electronic, microelectronic devices, and the entire airport command center height, according to GB50057-94 "design code for protection of structures" (2000 EDITION) regulations, can be divided into two types of lightning protection building.According to the rolling ball method (by rolling ball radius 45m) design of lightning arrester.Design method please refer to "design code for protection of structures" appendix four, decided to lightning number, layout, height, should be considered in the design of lightning arrester of local 30 years the gale wind strength, and have a certain margin.2, in order to reduce the lightning rod arrester to prevent acid rain on maintenance, corrosion, should be in the control center building roof installation stainless steel rod, its height and quantity according to the rolling ball method to calculate the protection range can cover the whole building center building surface and various types of antennas, which can effectively prevent direct lightning strike to protect the building roof and various types of communication security.In 3, along the road monitoring camera is mounted the tilt rod, toll station square head rod and LED sign top each installation of a stainless steel rod, to protect a pan-tilt camera and other equipment from lightning strike damage.In 4, highway toll station steel roof and large outdoor electronic screen top zygomorphic by installing a set of tower needle pointed lightning rod, to protect the toll station steel roof and electronic display frame structure against lightning damage.

Tall steel structure building fire safety measures

Steel is a kind of not extinguish the building material, it has the earthquake, flexural properties. In practical application, the steel can be increased relative to the building's load ability, but also can satisfy the construction design aesthetic appearance of the demand, and also prevents concrete and other building materials can not be bent, stretched defect, therefore, steel under construction industry favorite, monolayer, multilayer, skyscrapers, factories, warehouses, waiting room, lounge and using steel are common. However, steel building materials in fire prevention as there are some difficult to prevent defects, its mechanical properties such as tensile strength, yield point, and elastic modulus are as the temperature rises fall. The high-rise steel structure building is increasing, especially in some high-rise building steel structure, the more common way. High-rise building once fire accident, fire is not in a short period of time we fight, this requests us in the architectural design, increase building materials fire maintenance, in order to strengthen the fire resistance limit inside the building, and develop the necessary emergency plan, in order to reduce the casualties and property losses. Shrinkage. Using steel structure fire retardant coating maintenance component, this approachWith the fire insulation performance is good, the construction is not influenced by the geometric shape steel structure the advantages and restrictions, in general do not need to add auxiliary equipment, and the coating quality of light, there is a certain aesthetic decorative effect, which belongs to the modern advanced technology of steel structure fireproof measures usually at 450 degrees Celsius ~650 degrees Celsius in temperature will lose its bearing capacity, attack large deformation of steel column, steel beam bending, lead to, result from excessive deformation and cannot continue to use, and maintenance of ordinary steel structure fireproof limit is 15 minutes. This time also and component absorbing speed. To make steel structure information in the practical application of restraint fire area the lack of, must stop fire disposal, its purpose is to steel structure fire resistance design progress to standard rules limiting range of steel structure in fire to avoid rapid warming episodes deformation collapse, its measure is varied, the key is to take different measures according to different conditions, such as the use of insulation, refractory barrier direct flame ignition steel structure, reduce the heat transmission speed delay steel structure temperature rise, the weakening of time. But no matter in what way, its principle is different. Therefore,The author thinks the ideal of 4 kinds of steel structure fire protection measures must be pay attention to. Outsourcing layer. Take the words too literally, is in the steel surface to add outsourcing layer, can cast-in-situ molding, may also use the spray method. Cast-in-situ molding concrete outer layer usually with wire mesh or steel to enhance, to limit the shrinkage crack, and to ensure the strength of the shell. Spraying method to on site for the steel structure surface smearing mortar to form maintenance layer, mortar can be cement lime or gypsum mortar, also can be incorporated with perlite or asbestos. At the same time, outsourcing layer can also use perlite, asbestos, asbestos cement, gypsum or light made of concrete prefabricated plate, using adhesive, nails, bolts in steel structure. Water jacket hollow type steel structure filled with water is resistant to fire the most effective protection measures. This approach can make the steel structure in fire to low temperature, the water in the steel structure inner loop, absorbing its heating heat. The heated water cooling to stop recycling or by pipes into cold water to replace the heated water shield steel structure set in refractories consisting of a wall or ceiling, or member wrapped in two

Did not meet the quality performance in steel production

1, the steel structure plant in welding, light steel welded H beam flange is expected to open before stitching, weld not installed cited arc quenching plate caused the weld is not full, the edge of the pits incomplete fusion, with the base metal arrhythmia level; column foot, corbel leg length is less than the provisions of the design drawings, the phenomenon of the collapsed side of the fillet weld serious, generally lower than the base metal arc Department received more stomata; CO2 welding weld formation width inconsistent level of inconsistency, suddenly big and small; SMAW Weld is not straight, varies in width, undercut serious; welding slag splashing is not cleaned.
2, in cutting, cutting, the flange plate dimensions width varies, inconsistencies caused by the size of the H-beam and corbel, the contact of the steel beams and corbels upper and lower flange plates misplaced about a plate thickness; cutting edge deeper cuts, the board side depression or deeper serrations India, cutting roughness exceeded puzzle cutting edge is not perpendicular, stitching the wrong side and other excessive.
 3, when assembled, welded H steel no assembly tire rack, resulting in the height dimension of the H-shaped steel deviation web partial center; the wing webs docking, weld not flattening obvious irregularities; Strut webs uneven. Before assembly uncorrected.
4 In drilling, without the prior good triage drawings, in the open single row of holes, to open a double row of holes, the results did not fill holes retained in members. H-shaped steel column with corbel connection at the double row, while the beam with the same size of the secondary beam H-beam is a single row of holes, openings when opened double row, after installation, impact strength and appearance quality.
5, the assembly process, the steel columns corbels with H-shaped steel beams connected at the upper and lower dislocation around the dislocation, not to control size. Component transport and stacking process-free the shelving pieces of pad level stacked, but free to unload clutter piling up, and even let the member buried in the the mud heap ditch in the cause Deformation, bumps and pollution.
7, the component factory, steel columns, steel beams centerline mark is not marked, are quite common, to the installation and construction correction detection difficult.
8, rust and paint: rust sloppy, does not meet the grade requirements, paint soon return rust, flaking; uneven film thickness, the yang side thickness generally extra-thick, up to 250μ m, but the the nightside often in the 90μm about ( the indoor film thickness provisions 125μ m); paint before impurities is not clean, dirt, rugged, sagging more prevalent.
The 9 wing web splice length does not meet the requirements. Such as wing splice length should not be less than 2 times the flange width, flange and web splicing welds should be staggered 200mm or more, the web splice length is not less than 600mm. But it often does not meet the above requirements.

Steel structure anticorrosion technology comparison

Large steel structure, such as bridges, hydraulic structure, tower, chemical tank, pressure vessels and other anti-corrosion, particularly long-lasting anti-corrosion treatment (15-20 years) can have a variety of options.For example, hot-dip galvanized or aluminum technology, heavy anti-corrosion coating technology, thermal spray zinc or aluminum coating technology.Among them, the most suitable or thermal spraying aluminum or zinc coating (sealed closed layer).

If the use of harsh conditions for the steel structure of the protective service for 20 years, Zn or Al thermal spray coating life to 20 years; organic coatings with 3 years, 20 years for construction nearly 7 times, and the construction of temporary regardless of other loss caused by such enterprises, such as shutdown.Then, too, the thermal sprayed Al or Zn coated synthetic valuation is: 4~6 yuan / year m2, an average of 5 yuan / year m2; organic coating for 1.7-27 yuan / year m2, an average of 14.35 yuan / year m2, for thermal spraying technique about 3 times.

As a result of coating failure in protection period (20 years) in a construction caused a great loss.For example, the Yangtze River in Gezhouba Dam engineering of the lock gate and gate with a large Longmen crane steel structure, the steel structure of ship lift.The original paint anti-corrosion 2-3 years for an overhaul, overhaul period in each day, 20 reduction of ship traffic capacity, reduce near L200 ships navigation capacity, an annual average for 400-600 boats, causing great losses to shipping of the Yangtse river.Therefore the construction of the Three Gorges project important hydraulic gate, Huangbo River Bridge and Xialaoxi Creek Bridge required the use of thermal spraying Al or Zn coating protection.

From the comprehensive engineering using the integrated valuation, and paint coating technology and hot dip technology, thermal spraying technology has a very high ratio of performance to price.

Arc spraying technology in the fifty's has been in many countries of the steel structure manufacture and maintenance of the field have been used, but then the electric arc spraying equipment and technology level of restrictions, arc spraying is considered as a kind of high efficiency, low quality of thermal spraying method.Until six, seventy time the United States, Germany and some other developed countries on arc spraying equipment were relatively large transformation, greatly improving the coating quality, promote the arc spraying technology in steel structure manufacturing universal application, our country in the late nineteen ninties, arc spraying technology to become in recent years the most rapidly developing heat spraying technology.

For example, in recent years, Norway Dalseide &Floysand to build a total weight of 2300 tons of Norway offshore oil platform, the entire arc spraying anti-corrosion engineering using 14 G35-LD/U3 spraying equipment, spraying workers 100 3 months were sprayed with AlMg5 material 35 tons, is the world's larger thermal spraying anti-corrosion engineering model of long effect.Petrochemical Pipeline Anticorrosion were also used in thermal spraying anti-corrosion technology.

Of course, application of thermal spraying technology in construction, there exists a certain noise and dust.Steel structure for the factory production of environmental protection requirements very strict, and the field installation or old steel structure maintenance construction basically has no high requirements, but must strengthen the construction of personnel protection.

In four, long-term anti-corrosion steel structure engineering quality detection

Now, for the steel structure engineering design and construction, using quality of life tenure.In recent years, the government for the steel structure (e.g. bridge) design and manufacturing is presented in a clear life requirement.Therefore, no matter what anti-corrosion technology of steel structure for protection, in its production or maintenance of the process, must be professional and strict quality inspection and supervision.In the steel structure project of project of responsible spirit, use, construction and professional supervision party should attach great importance to this important link.

For every anticorrosion construction process, must make clear quality technical specifications.For example, steel pretreatment of blasting grade or manual pretreatment levels, anti-corrosion construction environmental requirements, paint construction procedure, proper selection of paint coating or thermal spray coating binding properties and thickness of the sample testing, sampling simulation environment corrosion test, coating appearance inspection and so on, all need the person responsible for.

Regardless of construction method, or the use of anticorrosive coating engineering, strict quality testing, must adopt a more sophisticated detection tools and equipment, but at present, many steel structure production manufacturers or engineering use to project construction how to detect coating properties, basic not very good value, some simply basic there is no testing equipment or condition.This is also a lot of steel structure service life is greatly shortened, and may cause destruction of the disaster accident is one of the main reasons.

Five, conclusion

Through the above analysis, the following conclusions can be drawn:

1 of today's society has begun to seriously long-term anti-corrosion steel structure this system engineering, it and the steel structure of the safety operation and life are closely related to the security.

2 reinforcing steel structure fabrication and maintenance of anti-corrosion construction management and supervision for engineering construction, use, and professional supervision is crucial.

3 in the steel structure design and production process, must have the professional anti-corrosion engineering and technical personnel and the participation of experts or guidance.

4 in the domestic, arc spraying technique developed in recent years is an emerging technology, has attracted more and more attention, and coating the organic combination of technology, will be more market advantage.(end)

Four software in the same light frame structure analysis and comparison

Often heard the saying: "a certain software than XYZ software in steel", of course, for those who say such things in general is not our professional, at most is a have a superficial knowledge of, however, as a real professional design staff and understanding of component design of body in the process of how many?In the design of steel structure industry has a large number of just the software user, therefore, as in the design and software development, it is necessary to do such a thing: use different software on the same conditions of an engineering calculation results, have a look how big the difference.

The selected field is light steel structure, because it is the most widespread use, but also on the amount of steel is the most sensitive structure, and I just had one such software, so often hear most is about the light steel steel quantity problem.

The software is current popularity in the industry, they are: 3D3S, STS, PS2000 and Maggie_GJ.

One, project brief introduction

The selected works as follows:

Two new 27m, four slope, slope, elevation of 7.5m, 1/20, 9m column, Q235 material.Diagram as shown below, recorded Liang Zhu's Cross Section specification (beam marked only the left cross, right symmetrical with the circle), as member number, beam member segment size also made a mark,

Load:

Roof loads: 0.2 KN/m2

Roof live load: 0.3 KN/m2

Basic snow load: 0.45 KN/m2

Basic wind pressure: 0.45 KN/m2

Without regard to earthquake.

Two, the analysis results

In order to get an accurate conclusion, we do not use that software to optimize the function of the component, but only for a given component section checking, here only the software the calculated number component control stress.

Control stress comparison table units: Mpa

Member number

3D3S

STS

PS2000

Maggie_GJ

1

180.6 167.7.

189 176.

210.8

184.9 170.1.

2

189.2 167.7.

178 164.

191.9

163.6

3

165.5 150.5.

168 154.

167.9

153.6

4

139.8 139.8.

117 105.

167.9

153.6

5

124.7 111.8.

117 105.

139.6

118.4

6

193.5 178.45.

190 176.

191.9

176.2

7

189.2 167.7.

180 167.

212.9

181

8

135.45 90.3.

152 76.

129.5

144.3 85.9.

On the side column (1 members), lateral support length considering the factor of 0.6 (knee bracing effect), control stress for the in-plane stability stress, brackets for the out of plane stability stress value.

In the column (8 components), control stress for out-of-plane stability stress, in this case, due to live load is evenly distributed, and the structure is symmetrical, in the column for axial force, so the section according to the calculation is relatively small, but the actual situation should be properly considering non-uniform distribution of load, the calculation results it is not considered, brackets for the in-plane stability stress value.

The beam (2-7 component), portal frame of "technical specification for steel structure of light-weight" (CECS 102:2002) regulations, in plane bending press for calculating its strength, in the plane to calculate the stability, but 3D3S and STS were given in-plane stability stress, but also the control stress.The previous "portal frame of technical specification for steel structure of light-weight" (CECS 102:98) mentioned in the beam in the plane of the calculation length of vertical spacing, this later in the rules have been removed.If as beam-columns are in-plane stability calculation, then the beam is a bending member, while the axial pressure is along the rod in the axial direction, or as horizontal direction to take?And according to this calculation length calculation of stability coefficient is still have significance?So like a column so as to calculate the bending in-plane stability is a little far-fetched.While calculating the out of plane stability is actually of member in bending calculation of overall stability, but also takes into account the axial force only, but still is the beam characteristics.So Maggie did not calculate the so-called in-plane stability stress.

Three, question words

From the above control stress meter, basically are very close, but PS2000 slightly high, it may be I used earlier versions.Therefore, we can say, the so-called save steel consumption is not the key software, but the use of software, the software is only a tool only, just like the same calculator.The count against the component design process that do not understand people who can easily complete the structural design of the ideal software even exists, it is also a potential bomb.It generates the construction drawings, can deceive layman's owner, also can let the poor professional knowledge you steep give birth to unlimited expansion of self-confidence, so that steel structure design is just so so.

The real structural engineer possess first is the mechanical foundation, for a loading structure, with various boundary conditions are generally stress state has a certain feeling, especially planar structure system, for complex spatial structure system, need have the aid of structural analysis software to help understand the stress condition.The second requires component design theory, the steel structure, axial compression, bending and the problems needed to be considered should clearly know.Also need to grasp the common node connection mode and the calculation method, this involves some experience.Also need to understand the design, but the process of making and installation of the knowledge, because many of the issues that need to be considered in the design stage.Of course, the most important or as a structural engineer responsibility.