Steel acceptance common questions 45 answer
Source: | Author:lichengcn | Publish time: 2017-08-09 | 6 Views | Share:
      1. What is a standing rib?
      Answer: a vertical bar is a steel bar that works in a beam, which is literally understood.The main function of the stand bar is that the Angle of the stirrup is supported when the root of the upper longitudinal tendon of the beam is less than the number of the corner of the upper part of the stirrup.So the vertical reinforcement is the longitudinal structural reinforcement that will stand up the stirrup.
      The current design specification of concrete structure gb50010-2002 stipulates that the diameter of the steel beam internal steel bar should be less than 8mm when the span of the beam is less than 4m.When the span of the beam is 4-6m, it should not be less than 10mm;When the span of the beam is bigger than 6m, it should not be less than 12mm.
      The rule of the rule of the rule of law: the position of the tendons is written in brackets to show the difference between them.
      2. What is the final page of "standard construction detail map change table"?
      Answer: The last page just gives an example, and there is no normative role.This is for the design institute.The purpose of the flat law is to not restrict the registered structural division to exercise its rights. Therefore, it is possible for the structural division to change the rules and structures that are not suitable for the specific works in G101.It is necessary to make clear that the content of the change is subject to change, so that the modifier should take full responsibility (including its risk).
      3. What is a long line?
      Answer: long jin is the result of seismic structural requirements, here the meaning of "long" is to make sure every parts of this part of the steel beam can exert its tension bearing capacity, to resist frame beams inflection point in the process of seismic action may change.Current < < concrete structure design code > > GB 50010-2002: the length along the beam top surface and bottom surface should be at least two root length of longitudinal reinforcement, the configuration of a, the seismic grade, secondary reinforcement should be not less than 14 mm in diameter, and should not be less respectively on both ends of the beam top surface and bottom longitudinal reinforced the larger cross section area of a quarter;The diameter of steel bar should not be less than 12mm.
      When the beam adopts double - limb hoop, it is sure that it can only be stiffened in the span.It is possible to have a brace if you use more than two legs.
      The tendons need to be lengthened by the length of the strap, and the stiffened bars are only 150, which is "tectonic interlacing", which is not connected.The tendons are required for "earthquake resistance" and the vertical reinforcement is "general".
      4, how to correctly understand the "regulations of technology of reinforced mechanical connection of general JGJ107-2003" article 4.0.3 said "Ⅰ joint is not restricted"?
      Answer: "regulations of technology of reinforced mechanical connection of general JGJ107-2003" will be sub divided into Ⅰ, Ⅱ, Ⅲ level, and the joint application of the rules: joint should be set up in steel structures smaller place, when need to be in high stress area set up joint of Ⅰ, Ⅱ, Ⅲ joint, joint area percentage were not restricted, no greater than 50% and not more than 50%.The so-called "unlimited" is conditional and should be treated with caution.
      In terms of the performance of the transmission force, any connected joints of the reinforced bars are weakened by the performance of the transmission, so there is no "unrestricted" problem.Reinforcing bar connection of other requirements, like a reinforced unfavorable setting, connecting two or more than two joint section of the structural requirements, avoid in the framework of the requirements for seismic resistance Liang Liang end and column end, etc., still should comply with the standard rules.
      However, when the design of the plain set is selected, the non-connection area of the seismic frame column shall be strictly enforced.
      5. Can the steel bar be connected in a connection area "without the prohibition of Ming order"?
      Answer: in fact, in addition to the important components of high seismic fortification intensity, there is no unconnected part which is strictly prohibited.Just ensure that the connection quality and control connection percentage are connected at any location.It should be noted that "avoid" the meaning of the requirement as far as possible, such as avoiding the node area, the area of the reinforcement, the stress (bending moment) and so on. 
      6. After the opening of the shear wall, how to do the vertical and transverse reinforcement of the steel bar in the hole? 
      Answer: the reinforcing bar is reinforced, the straight hook length is greater than 15d and the hook is not less than 5d.When the thickness of the wall is smaller or the steel diameter of the wall is larger, the horizontal setting of the 15d straight hook can be extended to the protective layer. 
      7. The horizontal distribution of the shear wall is outside?Or is the vertical distribution bar going to be outside?What about the basement? 
      Answer: in stress analysis and calculation, structure design without considering structural steel and steel bar stress distribution, but don't stress in the reinforced concrete structure there is no absolute steel, structural steel and distribution of steel bar has its important function, in the node usually has meet the structure within the anchorage length, whether the end hook and other requirements;It is usually required to meet the structure length, the starting point and the end hook.The distribution of steel bars is usually the reinforcing steel bar with the force bar and the diameter of the plate. 
Shall state that is said in the habit of shear wall, is the code for seismic design of buildings GB50011-2001 in aseismic walls, said its reinforcement for "horizontal" and "vertical distribution of" jin is inherited from the history of the habit, actually horizontal distribution and vertical distribution of shear wall reinforcement are reinforced, their connection and anchorage structure requirement all have clear rules, should be strictly implemented. 
      Shear wall mainly undertakes horizontal load and vertical load parallel to the wall, which has limited effect on the plane.From this analysis, the horizontal distribution of shear wall can be found on the outside and inside of the vertical distribution bar.Therefore, the "convenient rebar construction position" (from outside to inside) is: first floor, shear wall horizontal steel bar;The second layer, the vertical reinforcement of the shear wall and the stirrup of the dark beam (the same layer);The third layer, the horizontal bar of the dark beam.The vertical bar of the shear wall is at the top of the roof panel. 
      The basement walls of the basement are usually placed outside, but the interior walls are not necessary. 
      8. Why can't the steel end and bend point 10d be welded? 
      Answer: it's better to not weld than to weld, the standard for construction quality of concrete construction works GB50204?Article 5.4.3 of article 5.4.3 "shall not be welded".(2) GB50204?5.4.3 002?The joints of steel reinforcement should be set in the stress less.Two or more joints are not suitable for the same longitudinal force reinforcement.The distance between the end of the joint and the starting point of the steel bar should not be less than 10 times the diameter of the steel bar. 
      9. What is conceptual design? 
      Answer: conceptual design is to use human's thinking and judgment to determine the basic problems in structural design from the macro level.The concept design includes a wide range of factors, and there are many factors to consider, not only to analyze the big principles in general layout, but also to take into consideration the details of key parts. 
      In answer to this question, professor Chen qinglai explained that the concept design was white, and that it was a relatively advanced "shooting brain bag" that was not clear, but it worked.Otherwise the structure is too heavy!Without decades of experience and a deep understanding of the nature of the structure, it is not allowed to "clap". 
      10. How to control the rebar lashing, spot welding and spot welding? 
      Answer: the steel binding, lack of clasp, leakage resistance spot welding, the limitation of virtual welding standard, the new national standard for construction quality acceptance of concrete structure engineering "GB502004-2002 did not make specific requirements, but the original national standard" reinforced concrete engineering construction and acceptance specification GBJ204-83 "article 5.3.1 has the very good reference, these requirements can be made clear in the construction organization design or made a provision in the enterprise standard, is advantageous to the construction and conducive to acceptance.The intersection of steel bars should be fastened with wire;The steel wire mesh of the board and the wall, apart from the intersections of the two lines of reinforcing bars, the intersections of the intersections can be intersected with each other, but it is necessary to ensure that the stress reinforcement is not shifted.The reinforcing bars of the bi-directional forces shall be fully fastened;The stirrup of the beam and column should be set vertically with the stressed steel bar except for the special requirements.The straggled joint should be staggered along the force direction;Lap (4) column of the vertical steel, Angle steel bar curved hook should be 45 ° and template (polygon pillar for template inside share the Angle, round column should be tangent vertical and template);Intermediate steel hook should with template to 90 °.If use internal vibrator casting small cross section column, hook and the Angle of the template minimum shall not be less than 15 °
      11, how to properly use the code for concrete structure engineering construction quality acceptance GB50204-2002 "when a continuous casting more than 1000 m3, the same proportion of concrete once every 200 m3 sampling shall not be less than" the provisions of the block making? 
      Answer: "construction quality acceptance of concrete structure engineering GB50204-2002 paragraph 1, article 7.4.1 paragraph 3:" 100 per mixing disc and no more than 1000 m3 with mixing proportion of concrete, sampling shall not be less than once;When a continuous pouring exceeds 1000m3, the same proportion of concrete shall be sampled at less than once every 200m3.This is a lot of engineering understanding is "over 1000 m3 generally every 200m3 sampling"!Such operation, even in such an abnormal phenomenon, today 9 continuous production 900 m3 concrete sampling, a building block production, tomorrow a building continuous production 1050 m3 concrete sampling 6 block, this is clearly not correct understanding and use of standard clauses.The correct understanding should be: not over 1000 m3 per 200 m3 sample, but a sampling of more than 1,000 m3 per 200 m3.So for continuous production of 1050 m3 concrete, sampling should be 11 times, namely before reaching 1000 m3, once every 100 m3 sampling, a total of 10 times, more than 100 m3 of 50 m3 sampling time (less than 200 m3 also consider) at once. 
      12. In engineering, column reinforcement is often encountered because the measures should not be taken to lead to the deflection of the column. If the reinforcement is corrected at the bottom of the column, is there any more suitable method? 
      Answer: the column rebar deflection is mainly caused by the "awkwardness" of the longitudinal reinforcement, and the fundamental solution to the problem is the reform and lap. 
      13. How to select the basement wall to stop the water tenon? 
      Answer: should be clear in construction organization design. 
The underground engineering waterproof technology specification GB 50108-2001 has made great changes to the construction of underground construction joints.The original specification recommended for concave joints, convex joints, stitching, all have been cancelled.Reason is concave joint, flange, ladder seam all have different problems, concave joint cleaning is difficult, the construction joints of waterproof reliability is reduced, flange and ladder joints are shuttering is difficult, the inconvenience of construction, but many engineering practice that several forms are still in the application of the construction organization design in the process of examination and approval in case of such situation should remind the careful choice.
      14. The horizontal reinforcement of shear wall shall not be extended to the dark column?(in horizontal direction, the length of the column is much larger than that of the lae)
      Answer: to the column to the edge, to its 03 g101-1 has clear structure, its principle is strong shear embedded column and wall body itself is a work as a whole, not a few components connection combination, dark column is not a column, it is the vertical shear wall strengthening belt;Dark column and wall thickness, its rigidity is consistent with the wall.The connection concept of two different components of beam and column cannot be applied.The wall of shear wall is closed by the side rather than anchoring. 
      The situation of the end column is slightly different. The specification stipulates that the section size of the end column should be more than twice the thickness of the wall, and the stiffness can change obviously, but it can be considered as the vertical edge of the edge of the wall.If the size of the end column is not less than the size of the frame column of the same layer, it can be considered by anchoring. 
     15. Is it true that the column wall is supported by the foundation and the beam is supported by the pillar and the beam is supported by the beam?. 
      Answer: yes.Find out who's who of the bearing is common sense, general (primary) structure if discussed, starting from the view of system science to see a problem, the pedestal of the individual parts of structure who also not who (as the shoulder mortar is not bearing the same arms), everyone in order to a common goal (function) together.Based on the specific circumstances of the components, we can find out who has the support of who, but it is more convenient to study the problems and standardize the practice.Compared to shear wall (including wall column, wall body, wall beam), the base is its support, but its support is "wall column and wall body" relative to the beam.
      16. What is the difference between the vertical distribution of shear wall and the column of dark column in the foundation?
      Answer: it is important to know that the longitudinal reinforcement of the wall edge of the shear wall is very different from that of the wall.The anchorage requirement for the longitudinal reinforcement of the edge member is very high, one is the requirement to insert the base bottom, and the second is the end must be more than 12d.For reinforced wall body distribution, please pay attention to the words: "can" keep a anchor length, anchor its condition is according to the level of seismic shear wall, when low seismic grade "can", but high seismic grade are strictly limited.The truth is not complicated.Shear walls subjected to earthquake back and forth, basically the centerline of the body with the wall for balance line (pressure zero), balanced line on both sides of the compression of the tension side and cyclical change, the bigger the tensile stress and compressive stress value outside the farther, to edge up to a maximum.The tensile stress of the edge member is greater than that of the wall, so as long as the longitudinal reinforcement of the edge member is guaranteed, the edge member will not be destroyed.The edge member is not damaged, and the wall cannot be destroyed before the edge member.
      17. In the non-frame girder, does the band have encryption and non-encryption?
      Answer: commonly referred to as the reinforcement area is a special term for seismic design.The frame beam is not as seismic structural requirements of the stirrup encryption district, but uniformly distributed load can be set up two different stirrup spacing, bearing end under shear is large, the requirements of the stirrup spacing should be relatively close some nature.
      Flat method of creative design content is separated from repetitive design content is reasonable, the designers adopt the method provides the design rules of digital symbol to complete creative design content, and repetitive design content is a large-scale standardized provided in the form of standard design, two parts for the corresponding complementary relationship, be short of one cannot, combined method of form a complete flat design;The corresponding complementarity is used in the design, which is the link of the connection information, corresponding to the construction detail of the corresponding code in the standard design.Therefore, the flat standard is designed as a "command design document" instead of "reference design information".
      18. What is the difference between the plain and other standard atlas?
      Answer: in the past we contact with a large number of standard atlas, is mostly "component class" "standard atlas, such as: prefabricated plate atlas, thin abdomen beam atlas, trapezoid truss atlas, large roof plate atlas, atlas for each" drawing number "(that is, a specific component), in addition to express its engineering practice, are also gives the definite quantity (volume, the usage of all kinds of reinforced concrete and the dosage of the embedded iron, etc.).
      However, the plain set is not a standard set of "component classes". It is not about a class of components. It is about the overall representation of the construction drawing plane of the concrete structure. It is simply called "flat method".
      The essence of "flat law" is to distinguish the creative work of the structural designers from the repetitive work.On the one hand, the repetitive parts of the structural design are made into standardized nodes.On the other hand, the creative part of the structural design is designed by using the standardized design notation, "the rule of the rule of law", so as to simplify the design.This is the original intention of the "plain law" technology.So, for every "flat law" atlas, half of it is about "rules of the rule of law," and the other half of it is about "standard construction detail".
      19. What is the constraint edge member?
      Answer: the constraint edge member is suitable for higher seismic grade shear wall.Its longitudinal rib, the reinforcement ratio and the shape have higher requirements.Binding edge artifacts range see the code for seismic design of buildings GB50011-2002 article 6.4.6 and "technical specification for concrete structures of tall building" article 7.2.16 JGJ 3-2002, the main measures is to increase the length of the edge of the component and its reinforcement volume ι c rate rho v.For the cruciform shear wall, the edge constraint member can be set at the end of the two walls respectively, and the cross part should be configured with the dark column according to the structure requirement.
      In terms of how to distinguish the constraint edge member from the design drawing, just look at the code of the member, and specify YAZ, YDZ, YYZ and YJZ as the constraint edge member.
      20. What is the meaning of "once" in the 54th page of G101, "once a mechanical connection or a welding connection or binding?"
      Answer: if the stipulated in the standard set of long tendons minimum diameter small upper negative bending beam reinforcement, the upper bearing longitudinal reinforcement with long diameter will be different, so you need to in across the left across the right connection position of "two" long "two".When the concrete design adopts the diameter of the beam with the diameter of the beam and the diameter of the bending moment of the beam, if it still needs to be connected, the contact points should be arranged in a "one connection" in the span of 1/3.
      21. If the frame column is extended to the base of the base, can it be greater than the "bottom"? 
      Answer: the security degree of different parts is different.If the root of the column is out of question, it is useless to be strong on the top. Therefore, the column is "seated" with a curved hook, which can ensure the strong root of the column.As for the bend structure of 10 or 12 d d, or even 200, this is not the main problem, 04 g101-3 page 32 at the bottom right "column wall inserted bar anchorage straight section length and the length of the hook table" presents a unified regulation, should be performed. 
      The anchoring of the column longitudinal bars, when an earthquake occurs, is not a problem even when an anchor is anchored.But when the earthquake happens, many of the components will enter the elastic-plastic state, and the column of anchor will not be guaranteed to be stable. 
      22.03 g101-1. What is the definition of "foundation top, embedded part"? 
      Answer: if the foundation is not set up, the base backfill, rigid facing the column has "unilateral" inlaying, but cannot be treated as "embedded part". 
      This question can be discussed in depth.The root of the column refers to two different situations.The "foundation top surface" is relatively clear, independent basis, cross-beam foundation, raft foundation must refer to the top surface of the foundation beam or board, and the box foundation must refer to the top surface of the box base.But the "embedded part" requires a high degree of structural knowledge to determine.There is no conclusive agreement on what kind of conditions are included in the "embed site", which is actually in the hands of structural designers at this stage.For example: the basis of the basement top surface should be at the top of the basement floor, but the basement can be viewed as a whole "infrastructure", its roof stiffness is definitely a lot larger than floor stiffness, and outdoor floor below the soil on the outer wall of basement also has considerable build-in effect, therefore, the basement roof as part of the column base "build-in parts".Also, there are some problems with the central column of the underground chamber if it is treated with the frame column above the ground.Or: buried in the soil of beam and column foundation to pull in the built-in function, under the beam to the top of the base and foundation: which one Duan Zhu because the embedded in soil, the mechanism of stress and deformation characteristics under the influence of the surrounding soil, therefore, it is equal to the frame column above the ground treatment also has some problems. 
      
23. G101 03-1 on page 67 of the structure of the frame pillar caps in the figure, there is a "pillar box part of the longitudinal reinforcement extends to the upper end of shear wall floor, principles to the general principles of the expert", could you tell me this sentence in to a layer of shear wall pillar box on the longitudinal reinforcement can replace a layer of vertical reinforced shear wall embedded column or wall?So you can cancel the reinforcing bars of the upper part of the shear wall and the upper frame.
      Answer: stretching up to one of the purposes of is to replace the upper column or dark column (end) overlap of longitudinal reinforcement, "when two components' overlap ', not repeated set of big value" is also one of the principle of distributed, this principle also applies to horizontal distribution of shear wall reinforcement and the beam, the level of dark beam longitudinal reinforcement, the waist muscle Settings when they met. 
      24.What is a frame support beam? 
      Answer: the name of the building on the drawing is KZZ, which is the frame support beam.The frame supported beam is generally eccentric tensile member, and suffers great shear force.The connection of the longitudinal steel bar of the frame beam shall be connected by mechanical joint. 
      In the habit, the frame support beam generally refers to the beam of the wall in the structure of the wall of the support of the wall of the wall, which has the frame support beam.Technical specification for concrete structures of tall building (JGJ 3-2002 article 10.2.1 puts it in the conversion of the components, including transfer beam, transfer beam has a more precise meaning, contains the upper column and beam of the wall, therefore, in the traditional sense of box beam is only one of the transfer beam.
      Of the column, beam stress is compared commonly big, sometimes stress becomes the fasting 垳 on bottom chord, should pay special attention to in the design.Therefore, it is necessary to adopt some structural requirements of frame beam. 
      25. Is it the best of the beam?But the beam is not the same as the column concrete, it is very inconvenient to construct.How to handle the construction seams? 
      Answer: the construction is inconvenient can reform "labor law".Construction seams shall remain on the top of the beam.
      26. Should the vertical bar of the balcony bar be placed on the outside or on the side? 
      Answer: inside, otherwise person one push, may connect person add the board to go out. 
      27. If the frame beam to shear wall area became a frame beam (BKL), so, frame beam of reinforced protective layer (BKL) is calculated according to the frame beam protective layer, or by shear wall protection to pick up on? 
      Answer: the question is very good, and the observation is more detailed.This problem is similar to the layer of protection that the underlying column is buried in the soil and above the ground. 
      There are two kinds of border beams, one is the frame of the wall structure of the pure shear wall, and the other is the frame beam in the frame shear structure extending into the border beam of the shear wall.The protection layer of the former can be taken by the beam or the wall can be taken according to the wall. The latter should be taken according to the beam, so as to ensure the size of the cage is unchanged. 
      The section b * h embedded in the soil should be appropriately enlarged, which is known as the "nominal size" and "actual size".It should reflect the principle of "the part to the overall", is not of a "local" buried in the soil column section obey the "whole" column section above the ground, but obey the whole cross section of steel reinforcement cage.So far, no book has been consulted.We intend to solve this in the relevant technical documents of the infrastructure. 
      It can be seen that there is still a large number of topics that need to be studied deeply in many aspects of the knowledge and some knowledge of the structure. Some of them seem small but have practical application value. 
      28. What is the definition of anchorage length? 
      Answer: simply put, the length of reinforcement required for the safety of the tensile steel in the pedestal. 
      29. What should be judged in the construction of technical documents, such as tension zone, compression zone, tension reinforcement and compression reinforcement, etc. 
      Answer: tensile, compression of concrete structure mainly refers to the concrete member cross section areas of tensile stress and compressive stress, in general, compressive zone mainly is bent, truss column, wall and flexural member (beam, slab) are bending area (across) the upper and the lower part of the negative moment area (cross-border);Tensile area is mainly refers to truss with lower chord, shaft and members (beam, slab) and flexural members are bending area (across) the lower and the upper portion of the negative moment area (cross-border), of course, compression member under large eccentric compression state may also exist in local tensile stress, the horizontal load (earthquake action and larger wind), the picture is more complicated, should be determined by the structure of the internal force analysis. 
      Steel tensile, compressive reinforcement in concrete structures is refers to the bearing force component in tension and under pressure after the stress of the steel bar, due to the effect through the bond anchorage reinforcement and concrete and the common stress, so the tensile region and steel, compression zone and the location of the compression steel.In addition, the shear force and torque can also cause tensile stress or compressive stress, which should be determined according to internal force analysis. 
      Had important effect on mechanical properties of reinforced structure, such as steel in tension and compression of anchorage, lap length has the very big difference, but for construction unit, to the difference in tension section steel in tension, compression, the compression area of reinforcing steel bar, in fact, it is difficult, and often, designers will lead to the mechanical analysis of internal force result for construction;Construction personnel basic conditions for mechanical analysis of the whole structural system, can, of course, through the general concept of the structure of the general judgment, but is not accurate, the reliability is not high, want to have a long experience and more profound language to master.Therefore, if there is any ambiguity, you should ask the relevant design unit.The reinforcement bars of the seismic frame beams should be connected and anchored according to the tensile consideration. 
      30. What are four and six legs? 
      Answer: for the beam, the root number of the vertical direction of the stirrup is n roots, and then the n leg hoop.

  31. The wall of shear wall often leaves a few tens of centimeters of masonry, construction is very troublesome, can it be placed in the main casting when the steel reinforcement is in place?
  Answer: from the Angle of convenient construction, the exterior wall beam should be able to make the window, the method that brick of two layers of beam is brick is inconvenienced construction, the window of the lower window is often because think of the non-main structure and forget the stick.When design didn't do it, do not allow construction changes without permission, the beam high thickening, not beam, the higher the better, for aseismic structures, the beam high thickening may cause "strong beam weak column", the transfer of structural weaknesses in the earthquake comes, may result in serious security hidden danger. 
  32. When the longitudinal tendon of the beam is two or more rows, the bending hook of the stirrup should be hooked on the longitudinal reinforcement of the second or above, while the actual project will only hook the first row. Is it correct to do so? 
  Answer: it is better to hook up the second row, which is not clearly defined in the current regulation.When the first row of the hook, the Angle should be larger, otherwise the hook will be at the top of the second rib. 
  33. Could you tell me how long it will take concrete pouring reinforced concrete column in the lower column after (or the strength of the concrete after reaching much), the main reinforcement of upper column electroslag pressure welding is more appropriate, code like concrete without the intermittent make specific requirements for this kind of technology.But I think should have certain strength requirement, if the concrete strength is not enough, when construction, it is easy to cause out of steel bar and reinforced concrete caused did not cause any node in the grip of quality accident. 
  Answer: the loading of concrete structure prematurely, the durability of concrete structure and the influence of creep cannot be ignored.It is generally believed that even if reliable stabilisation measures are taken, it will be at least 24 hours after the concrete initial condensate or normal temperature. 
  34. Normally the cross sections and beams are all in the same section, so how can the effective cross section of the beam be guaranteed?Section 6.3.3 of the technical specification for the structure of the concrete heteromorphic column (JGJ 149-2006) gives the nodes, which are large and 800 of the column edges, and the slope of 1/25.In reference to the similar situation, can we construct the slope of 1/6 by the column?Is reinforced by the slope of 1/6 to bend, is a representative reinforcement force is continuous or no difference to the quality of steel, and more than 1/6 of a word is a force of discontinuity or have an effect on steel quality? 
  Answer: the provisions of JGJ 149-2006 of the technical specification for the structure of the concrete heteromorphic columns are prudent.The British press 1/12. In fact, there are some problems, but the habits of our country should be corrected gradually. 
  35.03 G101-1 page 53 shear wall hole reinforcement structure, if the shear wall is the hole through the shear wall, the shear wall hole of reinforcing longitudinal reinforcement should be set for a few, the exact positions should be somewhere inside the wall, the spacing requirements? 
  Answer: strengthening the number of reinforcement bars should be more than or equal to the number of wall bars.It is not less than the thickness of the protective layer to strengthen the outer edge of the hole.The vertical reinforcement is "held" by the truncated horizontal band 15d, which is held by the truncated vertical bars;The minimum clearance requirement for the column and the end column is met.
  36. Note 4 on page 33 of 03g101-1, the HPB235 reinforcement bars are not bent when pressed.But the column is also the compression member, can not do the hook.Is there a contradiction with our practice?We have to do the hook when we use HPB235 reinforcement. 
  Answer: the reinforced concrete column will use HPB235 steel bar as the longitudinal force reinforcing bar, which is not economical.The reinforced concrete column is usually a "bending member", not a "compression member", and the column is not compressed. 
  37. Why should the rebar replacement have to deal with "formal design change documents", instead of the construction party's own calculation of its own and other areas? 
  Answer: article 5.1.1 of article 5.1.1 of the construction quality acceptance specification of concrete construction works is required to deal with the design change document in the form of compulsory provisions.This is because the steel substitution may affect the performance of concrete structures of the following problems: (1) diameter change, its protective layer thickness change, may cause the durability problem or the change of the crack width.The change of reinforcement variety and intensity level can result in the change of stress level, which can affect deformation deflection and crack control.The change of reinforcement variety and strength level can cause the change of reinforcement, considering that the design conditions of the internal force redistribution of structural components may not be satisfied.Construction unit is often not so design conditions and design intentions, with the so-called "strong or wait for area" for calculating the reinforced substitution might be wrong, so make the norms, should be strictly observed. 
  38. How to encrypt the column straps in the basement? 
  Answer: the column of basement belongs to "infrastructure" column, appropriate all high encryption. 
  39. When the inner horizontal bar of the corner wall reaches to the opposite side, is it possible to avoid the 15d hook? 
  Answer: to add 15d bend hook.The horizontal tendon is not bent, but the end is not completely the concept of anchoring, and the more important purpose is to realize the overall reliability of the turning part of the wall. 
  40. In the shear wall structure, should the top of the column and the longitudinal beam of the top column be the girder sinew or the string reinforcement? 
  Answer: the column rib bar tendon.
  41. When the bottom (or top) of the beam is designed for two rows of steel bars, what is the maximum allowable spacing for a row and two bars? 
  Answer: the closer the two bars are to a row of bars, the higher the position of the joint center, the greater the force majeure.But they have the minimum spacing requirement to ensure that the concrete is reliable and adhered to the two bars.The effective height of the beam is also considered according to the above principle.Therefore, the two bars usually only have a minimum net distance requirement, and there is no maximum spacing rule, which can be understood in this way. The minimum clearance is the maximum spacing (the designer considers). 
  42. What is a shear wall structure? 
  Answer: shearwall structure refers to the structure of vertical and horizontal action consisting of a shear wall.Shear wall is the anti-seismic wall, which is designed to resist lateral seismic force.The columns of the multi-layer structure can basically meet the resistance requirements and generally do not need to set the shear wall.Now, the structure of multi-storey or small high-rise residential buildings is not a shear wall structure, but it should be a heteromorphism frame structure. 
  43. What is the Angle of bending of the beam? 
  Answer: the function of stirrup has 3: it is as a transverse reinforcement for shear, enhance the shear bearing capacity of the component, the second is torsional (the practice of the new specification will torsional stirrups and the practice of seismic reinforcement of unification, is no longer required to do the lap of 15 d), 3 it is fixed longitudinal reinforcement, make its accurate positioning, have the effect of handling reinforcement.Stirrup still has an important role is often ignored, namely confining hoop core concrete, caused the passive side pressure and enhance the bearing capacity of core concrete, the effect on improving the ductility of the member is very large. 
A fixed longitudinal steel bar requires a slightly greater than or equal radius of the Angle of the band and is greater than or equal to the minimum bending radius of the steel bar (relating to the performance of the steel). 
  44. Which diameter shall be calculated for the length of the rebar and the joint of the joints in different diameters? 
  Answer: the force needed to be transmitted by the joints in different diameter steel joints depends on the bearing capacity of the smaller diameter rebar.Therefore, the length of the lap should be calculated according to the diameter of the steel bar. 
  Stirrups restricts lap lap section steel bar caused by force the separation of trend, therefore, according to the principle of its safety in stirrup diameter of not less than coarser rebar diameter d / 4, and stirrup spacing, on the other hand, should take a smaller value, according to the principle of its safety calculated on the diameter of the fine steel stirrup spacing (5 or 10 d d). 
  45. Is the lower reinforcement of the frame beam under pressure in the support position? 
  Answer: when the beam of seismic frame is subjected to lateral action (such as earthquake action), the lower reinforcement of the frame beam is subjected to tension and pressure in the support area, not just under pressure.