Frame Structure Anti-earthquake Design Way of Thinking-毕业作品网站

Currently, the anti-earthquake norms all round the world almost adopt to a kind of way of thinking: The adoption presses the earthquake strong or weak of possible situation to divide the line earthquake cent area; According to everyplace the history occurrence of the area earthquake of covariance result or to geology structure of the history investigate to have to explicit statistics the meaning establish the sport peak in waterproof and quasi-ground value acceleration; Make use of again the reaction acceleration that the acceleration reaction composes different period; Get a design to use acceleration level through earthquake dint adjust met coefficient R. In the meantime, most nations all approve such point， establishing to defend the earthquake intensity level can take to use a different value, choosing to use to establish to defend the earthquake intensity level more and highly, the ductility request of the structure also more low, choose to use to establish to defend earthquake intensity level more and lowly, structure of ductility request more high. The structure ductility guarantee of precondition is the ductility of the member, pass again an effectively reasonable conjunction in adopting a series of measure guarantee member the foundation of the ductility, the structure system choice is reasonable in the meantime, the degree just distributes reasonable of under condition ability basic assurance structure of ductility.

1．Simple Review of Anti-earthquake Design Way of Thinking

The development that constructs the structure anti- earthquake is along with people all the earthquake move with the structure characteristic of the understanding is continuously thorough but develop gradually, however, from is born up to now the history of a hundred years, have mostly several to develop a stage as follows:

(1) Quiet dint stage: It first from a Japanese professor passed to harm to prognosticate the anti- earthquake design theories that put forward with the theories understanding at that time to the limited earthquake, being applicable to only just rigid body structure. It didn't think characteristic and the place difference to consider structure to the influence that constructs structure.

(2) Respond the table stage: Along with vibrate to record of obtain and the development of the structure dynamics theories, the Biota professor of the United States put forward flexibility to respond the concept of the table in 1940, respond the table is list the freely flexible system, it was obtain of numerous earthquakes record of encourage, the structure period or respond of the relation, include the acceleration reaction table, the speed responded a table, moved to respond a table. It consider the motive characteristic of the structure, it still is the foundation that all countries norm design earthquake dint takes a value up to now. The calculation of the earthquake function dint usually use shears with the bottom and flaps a decomposition to respond a table a method, flapping a decomposition to respond a table a method of basic define: Suppose the building structure is the line flexibility more freedom degree system, making use principle of flap a decomposition and flap a type, it will solve a freedom degree the earthquake of the flexible system to respond to resolve for solve an independence of etc. the effect single freedom degree flexible system most the heavy earthquake respond. Then begging should in each function affect that flaps a type. At this time, according to consider the way dissimilarity of the earthquake function, adopt a different array, group method, order flexible system to many qualities of the flat surface vibration, it can use a SRSS method, it is according to suppose the importation earthquake as steady random process, each of a flap reaction is independent mutually but deduce to get; For consider even-twists many qualities that the lotus connect to order flexible system, the adoption CQC method, it lies in with the main differentiation of the SRSS method: Suppose when flat surface vibrate each flap a type independent mutually, and each contribution that flap a type increased along with the frequency high but lower； But even-twist lotus connect hour each flap a frequency span very small, close together and higher flap the frequency of the type and may near to this relativity that will consider a dissimilarity to flap a very much, also have influence of turn round the weight and not necessarily increase along with the frequency high but lower, sometimes higher flap the influence possibility of the type big in lower flap the influence of the type, it will consider more influences that flap a type while comparing SRSS. The bottom shears the dint method in consideration of the special of the structure system to the simplification that flaps a decomposition to respond to compose a method, be the building height not big, took shearing to slice to transform as the lord and the quality to follow height to distribute more even structure with degree just, the structure vibration moved to respond usually with the first flapped a type for lord, and when the first flapped a type to near to in the straight line, can flap a decomposition method simplification to shear the dint method calculation formula for the basic bottom. The level earthquake function that each quality that this basic formula calculation get order can better reflection just degree bigger structure, but when structure the basic period was long, the place characteristic period to compare with hour, the calculation income coping earthquake function be partial to small. of course , the Anti-earthquake Norm provision, be the structure basic period more than 1.4 place characteristic period, at coping additional level earthquake function.

(3)the motive theories stage: Along with move understanding and comprehend to the earthquake of deepen continuously, know to some shortage of the reaction table, such as to the earthquake move hold of influence consideration not week, and the exaltation of the calculator function, make the motive method develop gradually, its essence solves a square distance of motive directly, but because of earthquake the ground sport acceleration is very irregular, it can't beg for differential calculus square distance, it shuts to match a solution, so adopt number integral calculus method more. Usual way of doing is carry on a continuous cent a segment a processing towards having already record of the earthquake wave, each data all see do the constant, then the function get to structure up, pass an equilibrium and square distance of motive to beg at the moment of the acceleration, speed, move reaction, moving with ex- the acceleration, speed, the segment to carry on folding to add immediately after folding the result for add as the beginning that descends at that time a segment to start a data, pushing according to this kind, end beg structure at the give for low week again and again the earthquake wave under of the acceleration, speed and move the dint reaction variety process.

(4) At American Northridge earthquake in 1994 and Japanese Kobe earthquake in 1995 after, the beautiful day scholar put forward again according to the anti- earthquake design method of behavior, it was during the period of usage to make the building structure satisfy various requests that used function according to the basic thought of behavior. Tradition according to the design method dissimilarity of the dint, adjudicate to the structure function mainly is according to move standard, move index sign to come with the different to the structure function to carry on a different control. But descend structure because of the big earthquake of not- flexible transform hard and accurate estimate of, make to can stay around according to the design method of behavior theoretically. But put forward its aggressive meaning to have 2:00 at least:

b. The part that knows an original anti- earthquake to design norm is unsuited to reasonableness.

Conduct and actions according to the foundation of the function anti- earthquake design, should to the particular level earthquake function of a certain covariance meaning under of the structure move, the speed and acceleration carry on accurate valuation, should also have a reasonable of valuation method with available valuation tool. It is exactly because of this purpose, put forward and developed the Pushover method and ability to compose a method. The basic way of thinking of the Pushover method is an adoption the quiet dint add to carry, supposing the side of the some penny cloth form toward lotus to carry a function on the structure, adding to carry gradually until attain the structure control point target to move or the structure break, getting the level side of the control point to move to shear the dint relation curve with substrate thus, evaluating in order to the anti-vibration ability of the structure. The Pushover method depends on to distribute a form and play the plasticity reaction table target to move to really settle in the side force.

2．Basic Way of Thinking of Frame Structure Anti-earthquake Design-ductility Standard

After the flexibility respond table put forward, the people's detection computes to gain from here of the structure respond with the actual earthquake the breakage phenomenon of the structure contain certain antinomy, mainly is press the flexibility reaction table to calculate of the structure responded the acceleration as habitual to design the earthquake dint to take to be worth big quite a few at that time doubly, and took to settle according to the habitual of the function of the design earthquake dint descends the house structure of design, the harm of the structure system wasn't serious in the earthquake.60's last century, the New mark passed to start to the beginning of different period just degree homology of the single freedom degree the system carried on analysis under the situation that many waves input, put forward etc. moved the principle and etc. energy principle, and put forward the concept of the structure ductility. Studied single and free system to accept defeat the level and flexibility thoroughly again from the relation of flapped the biggest not- flexible motive in the period and structure to respond afterward, this be customarily say of the theories of the R-μ -T effect. Passing these researches, announcing to public the ductility ability and plasticity to consume an ability is a structure Be taking to use to accept defeat level under not high circumstance, at big earthquake under the structure doesn't take place severity to break and doesn't don't tumble down of assurance. Arrive here, concerning the design earthquake dint's taking the basic problem of the value size have to arrive understanding definitely, be the anti- earthquake the earthquake dint take a value of the size isn't a number of assurance, but with the structure ductility function and consume the ability mechanism related quantity value. Here what to need to be explain BE, designed the earthquake dint to take a value to resolve a problem only, but to the structure ductility function guarantee of the measure have to can also promise, this will at underneath a section discuss.

Currently, the anti- earthquake norms all round the world almost adopts so a kind of way of thinking: The adoption presses the earthquake strong or weak of possible situation to divide the line earthquake cent area; According to everyplace the history occurrence of the area earthquake of covariance result or to geology structure of the history investigate to have to explicit statistics the meaning establish the sport peak value in waterproof and quasi- ground value acceleration; Make use of again the reaction acceleration that the acceleration reaction composes different period to descend structure to; get a design to use acceleration level through the earthquake dint adjustment coefficient R. In the meantime, most nations all approve such standpoint, establishing to defend the earthquake intensity level can take to use a different value, choosing to use to establish to defend the earthquake intensity level more and highly, the ductility request of the structure also more low, choose to use to establish to defend the earthquake intensity level more and lowly, structure of ductility request more high. The structure ductility guarantee of precondition is the ductility of the member, pass again an effectively reasonable conjunction in adopting a series of measure guarantee member the foundation of the ductility, the structure system choice is reasonable in the meantime, the degree just distributes reasonable of under condition ability basic assurance structure of ductility.

Underneath this kind of discusses the our country anti- earthquake norm mostly way of thinking, the current Chinese norm didn't adopt a variety to establish to defend the earthquake intensity level to take to use, but don’ Ted add a distinction of unify an adoption of the earthquake dint adjustment coefficient R=1/0.35;In the meantime, mostly according to establish a dissimilarity of defend the earthquake intensity, divide the line the different anti- earthquake grade, fix attention on in establish to defend earthquake intensity differently, adopt the anti- earthquake measure of the different assurance ductility. Very obvious here exist a misunderstanding of concept, also be according to the theories of the R-μ -T effect, the little more than earthquake dint adjustment coefficient R=1/0.35, should give the same ductility guarantee measure to the structure, but the Chinese norm adopt the different ductility guarantee measure, along with anti- earthquake the exaltation of the grade, ductility guarantee the ability correspond to strengthen. This kind of usefulness of the way of doing under way and not the line motive respond of verification, can describe so as a result mostly: For the district of 8 degrees 0.3 g and 9 degrees 0.4 g, because of correspond of the anti- earthquake grade is higher, the measure of the guarantee ductility is also stronger, so generally and more safe; And for the district of 6 degrees 0.05 g and 7 degrees 0.1 g, gain from here to of the level earthquake effect be partial to small, the general lotus carries an array, group is carried the control function by the gravity lotus, although to should of the measure of the guarantee ductility isn't very strong, can also guarantee structure generally under the big earthquake of not- flexible transform of function; But to the district of 7 degrees 0.15 g and 8 degrees 0.2 g, circumstance another the person worry, because of at the lotus carry an array, group, the earthquake function can have generally control function, but correspond measure of guarantee the ductility and be partial to weak, so difficult don't need to exist certain potential safety hazard to suffer from. See again other national earthquake dint adjustment coefficient R to choose to use, in order to have kept concrete understanding of view:

European common body EC8		New Zealand NZS3101		American UBC1997		Chinese GB50011 - 2001
The DC"L" low ductility	2.5	The flexibility responds structure	1.25	General frame	3.5	1/0.35 ≈s 2.86
In the DC"M" ductility	3.75	Limited ductility structure	3.0	Medium frame	5.5
The DC"H" high ductility	5.0	Ductility structure	6.0	Special frame	8.5

3．Ability Design Method

Top a part emphasized to discuss the design earthquake dint to take the problem of the value, but wanted to promise structure under the big earthquake of function, also need to establish the valid anti- earthquake measure, make the structure really have need of keep vertical loading under the dint condition not- flexible transform an ability, this be the so-called ability design method.

Ability design method from New Zealand the reinforced concrete anti- earthquake expert scholars such as the T. Parlay and the R. Park etc. development with initiate, main way of thinking is to the member occasionally member dissimilarity inside the piece is subjected to the dint form of the loading ability differ of control, promise the reinforced concrete structure formation the beam swing joint organization and ductility bigger is cut noodles to be subjected to the dint breakage appearance, make the structure have to play plasticity to transform function enough, promise big earthquake hour have an enough ability to consume to spread function, avoid creation brittleness to break and appear disadvantageous of organization form. The key of the ability design method is the anti- earthquake design that leads the control concept into structure, there is the leading formation of the purpose to the beneficial breakage mechanism is to the structure and break mode, avoid not reasonable of the structure break appearance, and try assurance to anticipate to break part to play plasticity to transform an ability.

The ability design method mainly passes the following three kinds of measure to give assurance:

1. Enlarge pillar opposite in the anti- of the beam-curved ability, artificial of leading of the structure swing joint part.

2. Raise opposite in is cut the noodles loading dint of the anti- shear ability, avoiding appearing non- ductility to shear to slice breakage.

3. To the part that appears the plasticity swing probably, the adoption corresponds of structure measure, assurance necessity of not- flexible transform function.

First, the reasonable part of the swing joint carry on a discussion, all countries mostly of the way of thinking inclines toward to make the project that the beam carries first to carry to appear in the pillar about and all. This kind of swing joint project has a following advantage: The ductility of the beam is easy to a control, and under general circumstance compare pillar of the ductility is big; The whole plasticity of the beam swing joint ratio pillar swing joint formation transform small; The plasticity of the beam swing joint organization formation transform more stable. There are also two kinds of different design methods while admit the premise of have the initiative the formation beam swing joint, a kind of from is a representative New Zealand of, incline toward the formation ideal beam swing joint organization, be promise the beam carries to appear the plasticity swing, but in addition to first floor, the post all doesn't appear the plasticity swing, at this time to in addition to the first floor pillar give post opposite compare bigger and super and strong coefficient(probably 2.0) in the beam, the advantage is a post(in addition to first floor) and doesn't need to be carry on to go together with hoop complicatedly at this time, because of adopt such coefficient can promise a swing joint very explicit. But is exactly because this kind of design method pursues the ideal beam swing joint organization to cause the first floor post compare weaker, the possibility for throng will be a swing joint, the plasticity that correspond and then have to adopt the structure measure to promise this part transforms function. In the meantime, such as if the first floor the influence of the swing joint upon the structure will compare greatly, once pressing and mating because structural whole tumble down, this has to be given guarantee up from the structure, increasing a structure of difficulty. Another project includes total body, Chinese etc. in the United States, Europe, this kind of project leading structure pillar swing joint the night appears in the beam swing joint, unlimited make the emergence of the swing joint in the meantime, but request structure and do not become the layer side to move structure, at this time to post of super go together with coefficient to compare with to request New Zealand of want to be small, goes together with the project that the stirrup takes in to control to the post adoption in the meantime. BE super to go together with coefficient to really settle problem comparison complications to the post adoption in fact: The beam carries the super influence for go together with for construct; The beam carries the plasticity swing to appear inside the dint is heavy to distribute of influence; Before accept defeat of the not- flexible characteristic may make the post bending moment physically big get in the flexibility analysis of bending moment ;The indetermination factor that the material difference bring; Growth of the structure not- flexible characteristic cause the influence etc. that the structure motive characteristic variety bring. According to the request of the ability design, the plastic hinge that shears the dint wall appears generally in the bottom of the wall limb. The joining beam shear the loading dint and ductility that the loading dint and ductility and entrance to cave of the dint wall connect beam contain very great relation, designing generally and possibly weak connect beam, the leading that has intention to know connects beam at earthquake accept defeat first, then is the bottom wall to accept defeat, also be anticipate the area of plastic hinge to accept defeat.

Avoided appearing to shear reason of slice the breakage early easy, be because of shearing to slice to break to belong to the brittleness breakage, disadvantage in promise the ductility of the structure, promise of way be according to the dissimilarity of the anti- earthquake grade to all beams, pillars, wall etc. the adoption is opposite to bend in the anti- of different super go together with coefficient.

The basic request that the anti- earthquake anti- shear is before the beam carry plastic hinge that big epicenter need turn to move and don't take place to shear to slice breakage, this sheared concept difference with the non- anti- earthquake anti-.For various different processing methods that the structure anti- of the member shears mechanism and the our country norm, there is the necessity elucidation here once. Beam: When anti- shake because of low week again and again the function made the beam appear to cross an inclined fracture, fissure, the inclined fracture, fissure distributed an anti- of come to a decision the anti- earthquake to shear the ability ratio not an anti- earthquake to have to descend, reason: The anti- shake of shear to slice to break occurrence after the end long tendon accept defeat, the fracture, fissure compare at this time greatly; The harm that crosses the emergence of the fracture, fissure to the concrete is more serious; The enlargement beam carried the number of the negative bending moment when anti- shake, cause bigger sheared the dint value to appear under the beam to carry, sprinkle plank now because of descending to carry to have no, break more easily. But at this time the function and function for non- anti- to shake of the stirrup differ only a few, in the norm to the consideration of this disadvantageous function is to adopt to resist to shear formula in to the concrete item 0.6 of fold to reduce, in the meantime, in order not to non- ductility of inclined break bad, while adopting to shake than the non- anti- more scathing restriction measure, cut noodles to shear the dint design value ratio non- anti- earthquake multiply 0.8 of fold and reduce coefficient. Pillar: It resist earthquake in the norm the anti- of the pillar shear the processing principle of the formula similar, also is adopt to the concrete item 0.6 of fold and reduce coefficient, adopt more scathing measure to prevent from equally inclined break bad, cut noodles to shear the dint design value ratio non- anti- earthquake multiply 0.8 of fold and reduce coefficient. But because of under general circumstance, the stalk pressure comparison of the pillar is big, this kind of pressure shears function to be partial to the anti- of the member after appearing the plastic hinge to the pillar emollient, according to this kind of way of thinking, pillar the adoption fold to reduce with beam similarly to seem to be not greatly reasonable. Wall: When the anti- shake, there is almost no related on trial data in domestic, is an adoption only the earthquake is to the non- anti- of the anti- sheared formula to adopt to the concrete item and the reinforcing bar items 0.8 of fold and reduce coefficient, in the meantime, in bar of and inclined break bad, adoption the restriction shear a way of press the ratio, cut noodles to shear the dint design value ratio non- anti- earthquake multiply 0.8 of fold and reduce coefficient. What to need to be explaining BE, under general circumstance, the part that shears the dint wall anti- to shear a problem probably is a lower part are a few floors. Node: The main acceptance shears the dint member, the node shears dint mainly is depend on the truss organization, inclined press pole organization, the stirrup of the stipulation effect three organizations or path to bear. The truss organization mainly is resist the reinforcing bar lord to pull should dint, inclined press the pole organization mainly is the lord that resists the concrete and the reinforcing bar creation to press should dint, the stipulation effect of the stirrup then strengthens the anti- of the concrete to shear ability. Along with the node concrete inside the area not- line development, the truss the function of the structure lets up continuously, and then both of function but be strengthening continuously. Therefore, the main target of the node anti- earthquake is under the situation that be subjected to dint again and again, pass to strengthen inclined press the pole organization and the stirrup to control an effect to avoid the core area concrete inclined to press thus a diplomatic corps to order at attain to anticipate of the big earthquake respond before do not take place to shear to slice breakage.

After shearing the discussion of mechanism to the above anti-earthquake, can be do with the function of the beam stirrup to tally up as follows: The first obvious function is to used for an anti- to shear; The second function controls concrete, this to guarantee the structure ductility contain count for much function, can also say literally here the obstacle that once high and strong concrete meet when used for anti- earthquake, this is related with the material of the high and strong concrete first, strength more high concrete more frailty, its should attain in the dint contingency relation biggest press should the contingency of the dint is smaller, this makes the design become the ductility member a difficulty with very great formation, is more high because of the strength of the concrete in the meantime, the stirrup rises the effect of the stipulation more bad, also can't the extreme limit of the enough valid exaltation concrete press a contingency, so cause to adopt the ductility of the structure member of the high and strong concrete hard get a guarantee; The third function is the stipulation function that carries to the beam lengthways reinforcing bar, prevent forming lengthways reinforcing bar lose steady, this has something to do with the special material of the reinforcing bar.