Chemical anchor bolt embedded parts for processing insufficient strength method

Chemical bolt anchoring technology to reinforce technology.In recent years, in building renovation, construction and change of use, or the existing building renovation and expansion and so on, chemical bolts anchoring construction as a new, simple and effective method in the construction of a fixed, is widely used.

1 chemical bolt component

Chemical bolt, screw, by chemical hose washer and nut.

Screw, washer, nut (six) generally have galvanized steel and stainless steel two kinds (in accordance with the requirements of hot dip galvanized).

Chemical hose (or plastic packaging pharmaceutical tube) containing the reaction resin, curing agent and silica particles.

2 parameters related to chemical bolt

Drilling depth: by anchor bolt type and size to determine required drilling depth, with a few exceptions, it is generally greater than the anchoring depth.In drilling, drilling depth control is particularly important.If used with the corresponding manufacturers anchor bolt is matched with the automatic protection of deep hole drilling machine (e.g. German-hui fish card anchor bolt are matched with the high-tech column cone type universal drill bit FZUB) drilling, drilling is very convenient.

Anchorage depth of anchor foundation structure: from surface to the bottom end of the threaded rod distance, is the important parameter influencing their bearing capacity.

Anchorage anchorage thickness: thickness equal to the anchored object thickness.If the anchor foundation at least plastering or tile, is covered with an insulating layer, then anchoring anchoring thickness at least equal to the thickness of the insulating layer plastering or tile, plus the anchored object thickness.

Margin: refers to the anchor bolt axis to the free edge of the distance member.

Spacing: refers to the distance between adjacent anchor axis.

Thickness: refers to the anchor base thickness.

In order to play a anchor bolt and the maximum carrying capacity, must guarantee a certain spacing, margins, thickness of the component, the data general to the manufacturers to provide technical parameters for.

Two, the process principle:

Through the synthetic resin mortar adhesive anchor and the wall of the hole, the bolt, anchorage foundation and the anchored object into a whole, thereby fixing component or increase the bearing capacity effect.

Three, process flow:

Setup: drilling hole cleaning reagent tube placement -- -- -- -- -- drilling bolts gel process hardening process -- a fixed object

1: the first borehole according to design requirements, drawings by spacing, margins set position, in the primary on drilling deep hole, aperture, must meet the design requirements.

2 hole cleaning: use air pressure blowpipe tools will hole floating dust and dust removal, maintain hole cleaning.

The 3 placement agent tube: chemical tube insertion clean hole, is inserted when the resin in hand temperature conditions as the honey flow, can use hose.

4 drill into the bolt is screwed into the screw drills: use until the medicament outflow.General use of percussion drill or drill drill, drill speed of 750 rpm.When the bolt is screwed into the tube to be broken, agent, resin, curing agent and silica particles mixing, and fills the anchor bolt and the hole wall of the gap between.At the same time, anchor bolts can also be inserted into the wet hole, but water must drain hole, the gelation process and hardening process of waiting time must redouble.

The 5 gel process: keep installation tools do not move, chemical reaction time to meet manufacturers to provide parameters.

6: the hardening process to remove the installation tool for chemical hardening, chemical reaction time to meet manufacturers to provide parameters.

7 fixed objects: to be completely after hardening agent, plus the washers and six corner fixing objects can be.

Four, the quality requirement and control

The 1 hole is best to use with anchor bolt matched to the drill bit, drill bit for use in drilling concrete models, drilling must avoid reinforced, one of which is to prevent injuries of main reinforcement, second is to prevent the injury bit.

2 before construction, must be on the anchor bolt material mechanical properties and heat resistance test.Test of anchor bolt material, via after the test, can be used, because in structure construction, anchor bolt shear more opportunities; in construction, anchor bolts are often used in fixed iron, iron plate welding and fixing other components, therefore, the anchor bolt (by welding) after the thermal mechanical properties is crucial.

3 in the construction site should be anchor site application conditions determine the test, in order to fully test bearing capacity.Field test can be used in construction site near, test design, supervision and construction method, the present.Field test generally adopt the axial tension, shear in general laboratory, test method with reinforced.

4 hole cleaning must be clean of dust and floating dust hole.

5 pipe in winter construction, should advance its heat treatment, to ensure that the tube is inserted in the hole when there is sufficient liquidity (in hand temperature, resin like honey flow).

6 screw must be screwed in to drill, direct type.

7 hole without water.

Five, application examples

In the Chinese Academy of Sciences Library, archives corridor construction of the steel structure, in the steel structure lifting stage, because the owners of the gallery features were adjusted, resulting in increasing load, the Design Institute of structural engineers review, member strength meets the requirement, but having the strength is insufficient, must be treated as early winter morning, when construction began, 9:00, temperature of -5 ℃, the processing steps are as follows:

1 of the original buried iron removal;

The 2 hole;

3 hole cleaning;

The 4 placement agent tube;

5 drill into the bolt;

The 6 gel process;

7 hardening process;

8 in the next three similar parts at the same time construction;

9 after 1 hours, field testing;

10 testing of all qualified;

The 11 fixed steel plates;

After the 12 plate with high strength micro-expansive filling material (compressive strength can reach C60).

Gallery of all the load function, through continuous observation, the point of deformation

manual arc weldingsubmerged arc

(1)
    Hand a welding arc is the earliest to develop a variety of arc welding method, is still the most widely used method. It is externally coated with the coating of the electrode as an electrode and filler metal, the arc is in the end portion of the electrode and the welder member between the surface combustion. The coatings can be generated in the role of the arc heat on the one hand the gas shielded arc slag covering the bath surface to prevent the interaction of the molten metal with the surrounding gas, on the other hand can produce. A more important role of the slag to produce physical or chemical reaction with the molten metal, or to add alloying elements to improve the performance of the weld metal. Manual arc welding equipment is simple, lightweight, flexible operation. A short seam welding can be applied to the maintenance and assembly can be used for the welding of the parts is difficult to achieve, especially. Hand arc is equipped with the corresponding electrodes applicable to the majority of industrial carbon steel, stainless steel, cast iron, copper, aluminum, nickel and its alloys.
(2)
    Submerged arc welding in a continuous feed wire as electrode and filled metal. Welding, at the upper surface of the weld zone, covered with a layer of granular flux, burning arc in the flux layer of the end portion of the wire and a partial base material melted and formed weld. Under the action of heat in the electric arc, the upper part of the solder melting slag and the metallurgical reaction occurs with the liquid metal. Slag floating on the surface of the molten metal bath, the other hand, can also make the one hand to protect the weld metal, to prevent air pollution, and produce physical and chemical reaction with the molten metal, improvement the extreme and properties of the weld metal; weld metal but slowly Ling. The submerged arc welding can be employed a larger welding current. Compared with manual arc welding, the biggest advantage is good weld quality, high welding speed. Therefore, it is particularly suitable for straight seam welding large workpiece girth. And most mechanized welding. Submerged arc welding has been widely used in the welding of carbon steel, low-alloy structural steel and stainless steel. Joints slag can reduce the cooling rate, some of the high-strength structural steel, high carbon steel submerged arc welding can be used.
(3) tungsten arc gas shielded arc welding
    This is a non-melting pole gas shielded arc welding, using electric arc between the tungsten electrode and the workpiece and the formation of the weld metal melting. Tungsten welding process does not melt, and only plays the role of the electrodes. While feeding argon gas or helium gas from the torch nozzle for protection. But also required the addition of the metal. In the international community, commonly known as TIG welding. Tungsten arc gas shielded arc welding heat input control, so it is connected to the sheet metal and an excellent method for backing weld. This method can almost be used for the connection of all the metal, in particular, suitable for welding aluminum and magnesium which can form a refractory oxide, a metal such as titanium and zirconium active metal. This welding method of weld quality is high, but compared with other electric arc welding, the welding speed is slow.
(4) a plasma arc
     The plasma arc is also a non-Electrode Arc. It is between the electrode and the workpiece compressed arc (called the forward transfer arc) to achieve welding. The electrode is usually used in the tungsten electrode. Generating plasma arc plasma gas is available argon, nitrogen, helium, or wherein both of the gas mixture. Also through a nozzle with an inert gas protection. Can be applied in the welding filler metal, can also be without filler metal. Straight due to its arc, plasma arc welding, and the energy density large, and thus the arc penetrating ability. Such as the the orifice effect generated in the plasma arc welding, for a certain thickness range of most metals can not open the butt, and to ensure penetration and weld uniformity. Therefore, plasma arc welding with high productivity and good quality welds. However, plasma arc welding equipment (including nozzle) is more complex, higher control requirements of the welding parameters. The tungsten electrode gas shielded arc welding can weld most metals, plasma arc welding can be used. Contrast, for 1mm below the welding of thin metal, with a plasma arc can be easier to carry.
(5) MIG arc welding
    This welding method is arc as a heat source, and discharged by a welding torch nozzle gas shielded arc welding using a continuous feed of the wire and workpiece between the combustion. MIG arc welding is usually protective gas: argon, helium, CO2 gas or gas mixture. Argon or helium as a shielding gas, known as metal inert gas shielded arc welding (internationally referred to as MIG welding); protective gas is an inert gas and oxidizing gases (O2, CO2) gas mixture, or CO2 gas or CO2 + O2 mixture for the protection of gas, or for the protection of the CO2 gas or CO2 + O2 mixture gas, collectively referred to as metal active gas shielded arc welding (referred to as MAG welding international). The main advantage of the MIG arc welding is easy for all position welding also has a faster welding, cladding and high. Metal active gas shielded arc welding is applicable to most of the major metals, including carbon steel, alloy steel. Metal inert gas shielded arc welding to apply to stainless steel, aluminum, magnesium, copper, titanium, zirconium, and nickel alloy. This welding method may further arc spot.
(6) The tubular wire arc welding
    Tubular wire arc welding is the use of continuous feeding between the wire and workpiece burning arc welding heat source that is melting a type of gas metal arc welding. The used wire is a tubular wire, contains various components of the flux tube. When soldering, the protective gas is applied, mainly CO. Flux thermal decomposition or melting, plays the the slagging protected dissolved pool, the role of permeability alloy and stable arc. Tubular wire arc welding in addition to the advantage of the MIG arc welding flux tube, so more advantages in metallurgy. Tubular wire arc welding can be applied to most ferrous metal welding various joints. Tubular wire arc welding has been widely used in some of the advanced industrial countries.
       2. Resistance welding
    This resistance heat welding method of energy, including of electroslag welding slag resistance heat energy and of solid resistance heat energy resistance welding. Because of the the electroslag welding more unique characteristics, described later on. Here introduces several solid resistance thermal energy resistance welding, spot welding, seam welding, projection welding and butt. The ERW Usually the workpiece under pressure at a certain electrode and the welding method of the connection by using a current through the resistance heat generated when the workpiece is melted and the contact surface between the two workpieces. Typically use a large current. Order to prevent arcing occurs on the contact surface and the To Forging weld metal, the welding process should always be applied pressure. Conduct this type of resistance welding, the welder surface of the piece good is of paramount importance for obtaining a stable welding quality. Therefore, before welding must be contact between the electrode and the workpiece and the workpiece and the workpiece surface clean-up. Spot welding, seam welding, projection welding Wu is the welding current (single phase) large (a few thousand to tens of thousands of amperes), short on time (a few weeks wave to a few seconds), expensive equipment, complex, high productivity, and therefore suitable for large mass production. Mainly used for welding a thin plate assembly of the thickness of less than 3mm. Various types of steel, aluminum, magnesium, and other non-ferrous metals and their alloys, such as stainless steel can be welded.
       3. High-energy beam welding
    This type of welding methods including: electron beam welding and laser welding.
(1) The electron beam welding
    The electron beam welding is the welding method of the heat generated by the concentration of high-speed electron beam bombardment of the workpiece surface. The electron beam welding, an electron beam generated by the electron gun and accelerate. Commonly used in electron beam welding: high vacuum electron beam welding, low vacuum electron beam welding and non-vacuum electron beam welding. The first two methods are carried out in a vacuum chamber. The welding preparation time (vacuum time) longer, workpiece size limited by the size of the vacuum chamber. Compared to the electron beam welding and arc welding, the main characteristics of the weld penetration and weld width small weld metal of high purity. It can be used in precision welding of thin material, can be used on very thick (most thick 300mm) components welded. All other welding methods for fusion welding of metals and alloys can be used electron beam welding. Mainly used in products that require high quality welding. Can solve the dissimilar metal, easily oxidized metal and refractory metal welding. However, is not suitable for high-volume products.

Structural materials industry development status of foreign film

Modern film structure was originally developed in Germany, its basic characteristics, mechanical characteristics,

design methods and potential as a structural system is also in Germany. Montreal German Pavilion, International

Exposition 1967 German design, and construction of membrane structure material, with a wide range of international

influence in the history of architecture. Membrane structure has become the integral part of modern architecture, the

construction of a number of well-designed membrane structures around the world.

Since 2002, China has PVC membrane structure material, PTFE membrane structure material and PVDF R & D and production

through the introduction of advanced technology and equipment in developed countries. However, since the application

time is short, the low level of technology, equipment limitations, the production efficiency is low, the product

physical properties (such as the self-cleaning properties, life) and mechanical properties (such as tensile strength,

tear resistance) with foreign the product has a larger gap, have become the film materials industry products to

enhance and broaden the urgent need to address the key issues in the application process At present, the annual

structural materials required for high-performance film more than 40 million tons (400 million m2), still 90%

dependent on imports.

The development of the membrane structure

In 1961, AIA magazine published the article of the "Tent", reveal to the people the importance of the membrane

structure, research and development from the perspective of building a modern structure of the film attracted

worldwide attention, represents the starting point of modern film structure , its technology and ideas reflected in

the 1967 World's Fair in Montreal, the epoch-making sum in the course of development of the membrane structure.

International Exposition held in Osaka, Japan, in 1970, many Japanese architects began to film new material to create

a new unique space provides an excellent opportunity to explore the potential of the membrane structure. Inflatable

membrane structure, the Expo USA Pavilion is low span ratio (relatively flat) is a milestone in the history of

development of the inflatable membrane structure.

In the 1970s, Geiger Berger developed inflatable membrane. Followed by a PTFE-coated glass fiber membrane become a

new type of membrane material, many giant membrane structure in the United States, such as the Pontiac city built in

the United States in 1975 with 80,000 seats Silver dome. These large span building that the membrane structure has

the advantage of the large space is no longer a dark and oppressive, these domes can economically across large space.

Because the inflatable membrane to be overcome, such as recurrent structural failure occurs, continuous pneumatic

high costs, the complexity of the control air pressure space closure and other issues, people began to explore the

new form of the film structure. In North America, the film structure as a permanent building development of new

features. Such as the 1980 University of Florida Stephen C. 0 Connel Center, 1984 Lindsay Park Sports Center, 1989

San Diego liberation Center, 1990 Chene Park amphitheater are the perfect shape and innovative combination of

structure.

The late 1980s, Americans B. Fuller proposed the idea of ​​a tensegrity dome and the earliest introduction of this new

structure to cover a large space, people began to use this the cable - rod combinations film structure instead of

early inflatable dome. 1986 National Sports Center in San Olympic Gymnastics Hall and Fencing Hall designed by

Geiger. 1988 Weidlinger designed Ilinois State University Redbird Arena, the Thunder Dome in 1989, the Georgia Dome

in 1992, these buildings are used tensegrity structure system.

1980s, many famous architects began designing membrane structures in European countries and improved design

standards, its project is unique, more unique. The 1985 Schlumberger was the first European research center has a

membrane structure, cable - composite structure of the film. Across traditional roof of the auditorium, football

field tends to darken the space below the membrane structure built in Europe was not the case. The 1990 Rome Olympic

Stadium membrane structure hanging down from space compression ring frame is both lightweight and aesthetically

pleasing, become the most commonly used model across the auditorium roof, made more reasonable and economy than any

other structure.

Today, membrane structure has begun to spread throughout the world. Japan and South Korea co-hosted the 2002 World

Cup stadiums in Japan arena 10 stadium six membrane structure (Niigata Stadium, Kashima Stadium), Korea stadium 10

Stadium 5 using membrane structure (Seoul Stadium, Daegu Stadium), Saudi Arabia, JiDa Airport departure lounge

suspended membrane structure covers an area of ​​420,000 m2, is still the world's largest membrane structure building.

From the practical experience of domestic and foreign film structure has a strong vitality, has become a major

program of structural design selection.

The development of the membrane structure material

Europe and the United States, the film structure of the Early Japanese PVC coated polyester fiber membrane, the

membrane material having a higher strength, tear resistance is better able to meet the needs of the early membrane

structure the existence of the self-cleaning properties, but the material , impatience ultraviolet, short life, as

well as adverse climatic conditions may exist accident. Later, large span the membrane structure building, high

strength, good performance PTFE-coated glass fiber membrane since the knot has been more widely used. The 1990s, R &

D success PVF and PVDF membrane structure, and has been applied in the project.

Famous producers of the film structure is mainly concentrated in a few developed countries in the United States,

Japan and Germany. PVC film, and PVF film, the PVDF membrane mainly by France (Ferrari company), Germany (Mehler

(meters music) company, Durakin Company) (Seamen company) and South Korea (show Bo company) production; PTFE membrane

mainly by Japan Sun Industries strain type clubs, Asahi Glass Co., Ltd., Japan, and other production; addition, ETFE

film production only Japan's Asahi Glass Co., Ltd. and other three companies, due to the expensive, high construction

requirements only for specific sports venue construction.

Domestic film structural materials industry development status

The development of the domestic architecture of membrane structure

Membrane Structure in China relatively late development, starting in 1995, only the construction of a 3300m2 area of

​​the membrane structure, 1997 years ago, there were only a small number of small and medium-sized membrane structure

building; 8th National Games held in Shanghai in 1997, its main stadium grandstand cantilevered roofs membrane

structure canopy roof area of ​​36,000 m2, can accommodate 80,000 spectators. This is China's first large stadium roof

membrane structure, membrane structure opened a new chapter for our country, has a significant impact on the

development of the membrane structure. The Shanghai Stadium adopt fiberglass PTFE membrane material, all of the

Department of the imported products.

Membrane structures built within five years from 1997 to 2001, 37 million tons; membrane structure built in 2003 is

about 18 million tons; membrane structure built in 2005, in 2006 more than 33 and 40 million tons respectively.

Predict the membrane structure of our country will continue to grow at a speed of 15 to 20% per year, and will reach

60 million tons in 2010. With the growth of China's economic and cultural life of the rich, and more will be built

with novel functions, various forms of construction. World Expo 2010 will be held in Shanghai, the construction of

various types of exhibition hall and around the country vary in size membrane structure must be with the development

of the membrane structure technology, applications and more widely. Architectural membrane material has strong

vitality, is bound to be the mainstream in the development of 21st century architectural structure will be very broad

market prospects.

The development of the domestic film structural materials

Since the 1995 film structural materials applications in the domestic, high performance membrane materials mainly

rely on imports. The same time, China's enterprises, universities and other efforts to conduct the study of membrane

structure material substrate, coating processing technology, coatings and application performance, through the

introduction of technology and equipment, some Chinese enterprises have been able to produce PVC membranes, PVDF

membranes and PTFE membrane material. Ningbo Group Tianta, first developed PTFE fiberglass membrane material, 3m

glass fiber used 6m glass fiber used than foreign crude, large differences compared to the final product performance

and abroad; 2002 Shanghai Shen Dakota Bao Co., Ltd. is a full set of the introduction of the German company Mehler

(Miller) PVC + full set of hot melt PVDF adhesive film technology and German the KKA company's production lines and

equipment production PVDF membrane structural materials, the structural material of the membrane structure diagram

shown in Figure 6.

Figure 6 Shenzhen Middle School the stadium bleachers film structure

However, the domestic film structural materials due to the physical properties of poor or inadequate mechanical

properties, it remains difficult to meet the needs of the domestic large-scale engineering and industrial development

of membrane structure. Currently, 90% of the domestic film structural engineering materials imported film, such as

the 2008 Olympic Games in Beijing National Stadium - Bird's Nest, the National Aquatics Center - Water Cube all high

-performance membranes Germany FORTEX company and Japan's Asahi Glass Co., Ltd., the only two venues reached 320,000

m2 of membrane structure material.

The application prospects of the membrane structure material

The membrane structure is the latest development in a form that in the construction of the structure, to the

excellent performance of the fabric as the substrate, the use of a flexible cable or a rigid support structure to the

surface tension, thereby forming with a certain stiffness, capable of covering the structural system of the large

span space . The most important feature of the membrane is high strength, durability, fire flame retardant, self-

cleaning from ultraviolet rays affect the life of 15 to 25 years, with high transmittance, 73% of the heat

reflectivity, heat absorption small Bird's Nest steel structure engineering welding stress and strain control

techniques

I. Project Overview

National Stadium grandstand concrete frame structure with radial surround them and form the main roof space steel

structure completely separated. Space steel structure surrounded by 24-bay door truss within the stadium bowl

bleachers rotate made 22 bay through basic through. Structural components to support each other to form a mesh-like

architecture, composed Stadium "Bird's Nest" shape overall. All steel components form a structural and architectural

features.

Engineering ± 0.000 elevation relative to the absolute elevation 43.500m, saddle-shaped steel structure roof was

hyperboloid, north-south structural height of 40.746m EW structural height of 67.122m. The roof of the main structure

are box section chord section for basic l000mm x l000mm, lower chord section 800mm x800mm basic abdominal cross-

section of the rod is 600mm x 600mm, basic, intersecting webs with upper and lower chords, the roof rise 12.000m.

Vertical portfolio by 24 steel column supported by two 1200mm × 1200mm Box Column and a diamond-shaped steel

columns, each combination of steel column loads through it passed to the foundation. The basic structure cross-

section of the facade times 1200mm × l000mm, the top surface times structure cross-section is basic l000mm ×

l000mm.


1 steel structure design weight

Main truss: l2720 tons of composite columns: the structure of the 12,548 tons times: 11,670 tons
Stairs: 4137 tons bridleways: 800 tons Total: 41,875 tons

2 steel models thickness

The maximum thickness of the steel sheet lOOmm. When the plate thickness ≤ 34mm Q345 steel: when the plate thickness

≥ 36mm using Q345G daub material: a small amount of thick steel plate Q460, 8480ML steel. Local steel castings.

Thickness distribution:

- The combination steel columns in addition to a small amount of prism bottom of the column and the top is 90. lOOmm,

the rest is 50480mm, the vast majority of the other two square oblique column plate thickness for 30, 25, 20 mm.
- The truss chord individual segment 50mm, the rest are less than 40mm, most of them for 30, 25, 20 mm.
- The individual segments of the truss bottom chord 50,42 mm, the vast majority of 20mm.
The the - webs 20,14 lOmm majority of lOmm.
- Sub-structure of the plate thickness 36mm, the vast majority of less than 20mm.

3 steel performance


1 large size of the project, re-member tonnage

- Saddle-shaped steel roof long axis of approximately 333m, short axis approximately 280m: inner ring long axis the

approximately l82m, short axis approximately l24m: vector high 12m.
- The maximum weight of the composite steel column weighs about 520t per meter heaviest about lOt: main truss per

meter weighs about 3t.

2-node complex

- The main structure are large cross-section and the box member nodes in space listing the root of rod: time

structure node complex and changeable, less regularity.


Third, the construction program profiles

According to the adjusted preliminary design drawings and other technical conditions. Determine the final

installation program for the ground assembled altitude bulk construction method, T8-roots support system that is

arranged at the venue, the main structure of the slice or ground block assembly after forming, 800T and 600T crane

hoisted to the top of the temporary support, was divided into four districts J stages symmetry finished loading and

welding, after the completion of the structure and sub-structure of the facade of the main structure the T8

supporting system overall synchronization uninstall the final installation of the structure of the plane times.

Lamellar tearing problem analysis

Lamellar tearing risk analysis


Due to the formation of the welded joint is binding on the plate thickness direction, there is a certain tendency to

from the joints ways perspective, according lamellar tearing empirical formula:

LTR = INF (A) INF (B) INF (C) INF (D) INF (E):
INF (A) of the impact of the size of fillet S s larger value, LTR bigger. It should not be the large size of fillet.
INF (B) joints to form the way.
INF (C) to withstand the lateral restraint thickness Sa the influence of jLTR,; the greater, LTR the greater.
INF (D) is the binding degree of impact, restraint intensity R Yue, lamellar tearing the greater the tendency.
The INF (E) for the preheating conditions, using preheated advantageously.

According to the LTR of the calculated value know, the thickness greater than 40mm lamellar tearing great danger, but

produce lamellar tearing is mainly depending on the material of the steel, steel works optional its performance must

be meet the requirements of Zl5 ~ Z35, effectively prevent the emergence of lamellar tearing phenomenon in the

control of the stress-strain.

Five steel welding deformation and residual stress analysis and countermeasures

Welding deformation and residual stress is a major issue that must be taken seriously in steel construction, there

must be strict technical rules and countermeasures must be scientific and rational management, in the conduct of the

process of the project, so as to form a complete system management engineering, ensure the quality of the steel

structure engineering.

The basis of a welding deformation and residual stress analysis

The National Stadium steel structure engineering field welds divided into two main types: fillet weld and butt weld.

Generally fillet welding deformation is not too large, the residual energy is mainly present in the form of welding

residual stress of the steel structure of the weld and H ^ z: fillet weld is not a major force weld control of

welding The key to the size of the residual stress is the minimum size of fillet weld. The residual energy of the

thick plate butt weld shrinkage deformation of the weld and form of welding residual stress in the weld and H ^ z:

control of welding deformation and welding residual stress must be integrated governance. Practice has proved that:

welding stress and residual stress exist among the same weldment, both complementary and can be interchangeable, the

theoretical basis of the conclusions of the conservation of energy, see equation (1), (2).

Set the total weld energy E = 1:amounts. This unique structure has unlimited potential, able to adapt to a variety of

functions, and has strong vitality, will become the mainstream of the development of 21st century architectural

structure. (End)

The removal of a large steel structure industrial plant construction

1 Introduction
With the rapid development of China's urban construction, demolition and construction of the building. However, the construction technology research is still relatively weak. In this paper, the demolition and construction of a large steel structure industrial plants, facilities work a useful discussion on the demolition of similar buildings.
2 Project Overview
Because of the real estate development, a Beijing steel structure industrial plant to be removed. 48.8 meters long after the Found, plant east-west direction, north-south and 22.5 meters wide, 17 meters high eaves, roof trusses 21.5 m. Along the north and south walls have a row of nine steel components corbel, the cross-sectional shape shown in Figure 1. Plant north is a brewery five-story boiler room in Beijing, both the nearest distance of 8.45 meters. South, east and west as open space. The factory plan view shown in Figure 2.

3 plant structure analysis
The plant is a steel frame structure, both north and south walls of a row of nine symmetrical steel members corbels, symmetrical corbel connected through triangular steel roof trusses, steel beams connected through the top of the column adjacent corbels. The east and west walls each have two wind resistance with a long pass reinforcement column. Plant from top to bottom the distribution of five cement ring beam plant wall 24 wall of cement mortar bonding corbels and wall ring beam spacing 42cm Rachel steel. The plant by analyzing the overall structure is very strong, mainly support the force structure for the corbel, the column steel beams and steel roof trusses of the steel frame. Wall weight is borne by the ring beam.
The 4 planned construction program
In view of the structural integrity of the plant, and the tight schedule, and close proximity to the the brewery boiler room, the collapse of the program decided to use a one-time overall southward. Corbel steel components, construction sequence was cut off from the base portion of the first to use gas cutting after cutting the shape shown in Figure 3, and then use hydraulic hammer off the south and east ring beam, wind column, to the north and south of the wall in dead weight collapse under the action, then hydraulic shears from the top to the the drag directly south of the southeast corner of the corbel, it collapsed, and lead the overall structural instability and collapse.

5 force analysis.

5.1 parts cut corbel retain pressure on steel plate column instability calculation

Corbels cut, the most unfavorable conditions for the entire surface of the walls and pillars, steel roof truss weight acting on the cutting site at:

(1) axial compression calculated

σ = N / An ≤ f

σ stress of the steel plate column N of steel column pressures, An steel column cross-sectional area, f is the steel plate column can withstand the maximum compressive stress.

f = 190N / m ㎡

An = 550 × 16 = 8800mm

N ≤ f × ​​An = 190 × 8800 = 1672000N = 1672KN

Nmax = 1672 × 9 = 15048KN

F is the load weight

F wall = 48.8m × 17m × 0.24m × 19KN/m3 ≈ 3783KN

The F steel column = (2 × 1.3 +3 × 0.55) × 17 × 0.016 × 7850kg/m3 = 9074.6Kg ≈ 0.926KN

Because there are steel roof trusses and load for insurance purposes, the total weight taken a factor of 1.1.

F = (F the wall + F steel columns) × 1.1 = (3783 +0.926 × 9) × 1.1 ≈ 4171KN

Visible F <Nmax

(2) instability calculation

N / (φA) ≤ f

The φ component pressure stability factor determined by the slenderness ratio λ.

f = 190N / m ㎡

A = 550 × 16 = 8800mm

λ = 1400/16 = 87.5

φ = 0.548

N ≤ f × ​​Aφ = 190 × 8800 × 0.548 = 916256N ≈ 916KN

Nmax = 916 × 9 = 8244KN

Visible Nmax> F = 4171KN

5.2 overall collapse, the framework for stress analysis

Corbel by force when collapsed, mainly gravity and tension, steel roof truss clockwise torque. Horizontal direction by the force in Figure 4, it should be noted that due to the retention of the Western Wall, the northwest corner and southwest corner of the two corbel steel roof truss erection of the wall in the West, to the Western Wall axis formation leverage great torque. Two corbel column the lodging direction will be different with a few pillars.
Stress analysis above, the expected the corbel collapse direction shown in Figure 5.

6 construction effects

Calculated by analyzing the actual situation at the scene and found the steel column strength once collapsed, turn south of a row of steel columns at the bottom to keep steel plate, part cut off, leaving only the middle 1/3 of the width. After the fall of the actual situation and the situation is expected to match, were no influence in the north of the brewery boiler room.

7 Conclusions and recommendations

The difficulty lies in the demolition work corbel the collapse direction, we must ensure the absolute safety of the brewery boiler room. Do this by pre-analysis to determine the direction of the corbel collapsed, and then construction ensure dismantling success.

Door first deflection explanation on the source

1.PKPM about the interpretation of the deflection (from PKPM program description)

Steel beam deflection chart are given (constant load live load), steel beam deflection diagram (live load) under standard value. When checking specification for "light housing of portal frame steel structure technology procedures" (CECS 102:2002), given roof inclined beams, steel beam deflection of the standard value (constant load live load) under the slope change the map, slope the rate of change control procedures required not more than 1/3. The significance of the various graphics output is as follows:

1) Absolute deflection diagram span L is the "beams the distance between two adjacent column, the maximum deflection values ​​υ, refers to the span within the beam in constant live" or "live" the Dutch role under the maximum vertical value to the deformation. Flexible span ratio as a basis for the calculation and control: υ / L ≤ [υ / L]. The values ​​of the beam upper middle position indicates this cross beam torsion cross ratio υ / L, the beams the lower value indicates the value of the cross-largest deflection υ, unit: mm maximum deflection position in the cross. When checking is not satisfied, υ, υ / L values ​​are shown in red.

2) relative deflection chart span L is the "the crossbar single slope slope length, maximum deflection values ​​υ, refers to within a single slope slope length, beam in constant live" or "live" under the Dutch role relative deflection values. Flexible span ratio as a basis for the calculation and control: υ / L ≤ [υ / L]. The the beam upper middle position value, said torsion of the beam segment span ratio υ / L, the lower value of the beam, the maximum relative deflection of the beam segment, the value of the maximum deflection of the beam segment υ, unit: mm. When checking is not satisfied, υ, υ / L values ​​are shown in red.

3) inclined beams calculate the slope map, only when checking specifications the gantry frame light house steel structure technical regulations (CECS 102:2002), an output checking content. Inclined beams in the role of the standard value (constant load live load), the slope of the steel beam deflection of change control, the slope of the rate of change control procedures required not more than 1/3 gauge future, the graphics are displayed in red.



Description: the relative deflection absolute deflection deflection values ​​for a cross double slope difference is very large; For there is only one cross in a sloping or horizontal beam, the deflection of the two is exactly the same value. Relative deflection for deflection control, the program the absolute deflection flexible span ratio, span ratio control user input parameter input allowable scratch. The design should be selected according to the actual situation of the project control. By the right [control parameter menu item, torsion of steel beams cross view than the control parameters, modify, modify real-time display will modify the control results.

2.3d3s w / L of explain to (from 3d3s10.0 basic instructions)

Portal frame L meaning: (from << gantry frame light house steel structure design and construction difficult problem DEFINITIONS >>)

4 L more authoritative description: (from the steel structures magazines door steel errata)