咨询电话:0554-4991161
技术服务
联系我们

电话:0554-4991161
手机:18175036696 
         13588259339
传真:0554-4991161
地址:寿县炎刘镇二环
路与新桥大道路口向东100米

当前的位置:网站首页 >> 技术服务 >> 技术服务 技术服务

钢筋混凝土框架结构设计应从概念设计上着手注意几个问题

发布时间:2015-9-21 9:47:22 浏览次数:569
1.注意抗震设计。

(1)抗震设计的基点结构。抗震设计的基点是强度和延性。人们现在已经认识到可以利用钢筋混凝土结构屈服后的非弹性变形来抵抗地震,也就是将强度和延性两者相结合来抵抗地震。为保证结构的抗震能力,对结构设计而言,如果我们给结构设定较低的承载力水准,相应地就要求结构具有较高的延性水准;如果我们给结构设定较高的承载力水准,则结构需要的延性水准就可以较低。在这个问题的具体处理上,各国的理念存在一定的差异。

(2)能力设计法。能力设计法的基本思想为:为了使抗震钢筋混凝土结构在地震中形成所追求的“梁铰机构”或“梁柱铰机构”,就需要把不希望出现塑性铰或不希望先出现塑性铰(也就是不希望塑性转动过大)的部位的抗弯能力相对增强;为了不致在结构表现出所需的延性之前在结构的任何部位出现几乎没有延性的剪切失效,也需要相对增强各有关部位的抗剪能力;还需要采取必要的措施使可能形成塑性铰的部位具有足够的延性能力和必要的耗能能力。

2.关于强柱弱梁节点。这是为了实现在罕遇地震作用下,让梁端形成塑形铰,柱端处于非弹性工作状态,而没有屈服,但节点还处于弹性工作阶段。强柱弱梁措施的强弱,也就是相对于梁端截面实际抗弯能力而言柱端截面抗弯能力增强幅度的大小,是决定由强震引起柱端截面屈服后塑性转动能否不超过其塑性转动能力,而且不致形成“层侧移机构”,从而使柱不被压溃的关键控制措施。柱强于梁的幅度大小取决于梁端纵筋不可避免的构造超配程度的大小,以及结构在梁、柱端塑性铰逐步形成过程中的塑性内力重分布和动力特征的相应变化。因此,当建筑许可时,尽可能将柱的截面尺寸做得大些,使柱的线刚度与梁的线刚度的比值尽可能大于1,并控制柱的轴压比满足规范要求,以增加延性。验算截面承载力时,人为地将柱的设计弯距按强柱弱梁原则调整放大,加强柱的配筋构造。梁端纵向受拉钢筋的配筋不得过高,以免在罕遇地震中进入屈服阶段不能形成塑性铰或塑性铰转移到立柱上。注意节点构造,让塑性铰向梁跨内移。
3.注意构造措施。

(1)对于大跨度柱网的框架结构,在楼梯间处的框架柱由于楼梯平台梁与其相连,使得楼梯问处的柱可能成为短柱,应对柱箍筋全长加密。这一点,在设计中容易被忽视,应引起重视。

(2)对框架结构外立面为带形窗时,因设置连续的窗过梁,使外框架柱可能成为短柱,应注意加强构造措施。

(3)对于框架结构长度略超过规范限值,建筑功能需要不允许留缝时,为减少有害裂缝(规范规定裂缝宽度小于0.3mm),建议采用补偿混凝土浇筑。采用细而密的双向配筋,构造间距宜小于150mm,对屋面宜设置后浇带,后浇带处按构造措施宜适当加强。

(4)其它构造措施限于篇幅,这里不再赘述,请详见新规范。

4.关于“强剪弱弯”措施:强剪弱弯是保证构件延性,防止脆性破坏的重要原则,它要求人为加大各承重构件相对于其抗弯能力的抗剪承载力,使这些部位在结构经历罕遇地震的过程中以足够的保证率不出现脆性剪切失效。对于框架结构中的框架梁应注意抗剪验算和构造,使其满足相关规范要求。





1. Pay attention to the seismic design.

(1) the structure of the basis of seismic design. Seismic design is the basis of strength and ductility. People have now realized that can take advantage of the yield of inelastic deformation of reinforced concrete structures to resist earthquake, which is combining both the strength and ductility to resist earthquake. In order to ensure the seismic capacity of the structure, the structure design, if we give structure to set the bearing capacity of the lower level, accordingly requires structure has high ductility level; If we are to set higher bearing capacity level structure, the structure need to ductility level can be low. On the problem of the specific processing, there was some difference of the concept of all countries.

(2) the capacity design method. Capacity design method, the basic idea is: in order to make the aseismatic reinforcement concrete structure formed in the earthquake's pursuit of "beam hinge institutions" or "beam hinge institutions", unwanted plastic hinge you need to put plastic hinge or don't want to come first (that is, don't want too much plastic rotation) of the bending capacity of the relative increase; In order to not be before the ductility of the structure show the required in any part of the structure appear almost no ductile shear failure, also need to enhance the relevant parts of the relative shear capacity; Also need to take the necessary measures to make the parts of plastic hinge can be formed with sufficient capacity and ductility of the necessary energy dissipation.

2. About the strong column weak beam node. In order to realize this is under severe earthquake, let the beam end plastic hinge formation, inelastic performance of column end, and not to yield, but the node is still in the elastic work stage. The strength of the strong column weak beam measures, that is, relative to end section of the actual beam bending capacity of flexural capacity increases in the cross section at the end of the size, is decided after cross section at the end of the yield caused by earthquake plastic rotation can be no more than the plastic rotation capacity, and does not form "layer of lateral institutions", so that the column is not the key of the crushing of control measures. The size of column strong beam size depends on the structure of the beam end longitudinal reinforcement is inevitable with any degree of size, and structure in the beam, the plastic hinge at the end of the plastic internal force redistribution in the process of gradually formed and the dynamic characteristics of the corresponding change. When building permits, therefore, as far as possible to do the column section size bigger, make line stiffness of column and beam line stiffness ratio greater than 1 as far as possible, and control of axial compression ratio meet the specification requirements, to increase the ductility. When calculating the ultimate capacity, according to column design of curved distance will artificially strong column weak beam principle adjust amplification, strengthen column reinforcement structure. Beam end longitudinal reinforcement steel shall not be too high, to avoid entered the stage of yield in severe earthquake could not form plastic hinge or the plastic hinge is transferred to post. Pay attention to the node structure, let to the beam plastic hinge moved in across.

3. Pay attention to the construction measures.

(1) for the frame structure of the large span column grid, in the framework of stair place column due to the landing beam and is linked together, make the stairs q may be short column, the column length column stirrup encryption. This, easy to be ignored in the design, should be taken into consideration seriously.

(2) the window frame structure facade for the band, because of setting continuous window lintel, make the outer frame column may be short column, should be paid attention to strengthen the construction measures.

(3) the length is slightly more than the standard limit for frame structure, building function need not allowed, the seam is to reduce the harmful cracks in the rules and regulations of (crack width is less than 0.3 mm), recommended compensation concrete pouring. With fine and dense two-way reinforcement, construct the spacing should be less than 150 mm, the post-cast strip on the roof should be set up, after pouring belt according to the structural measures should be appropriate to strengthen.

(4) other structural measures shall be limited to, go here, please see the new specification.

4. About "strong shear weak bending" measures: strong shear weak bending ductility is to ensure that components, to prevent the brittle failure of the important principles, it requires artificially increase the bearing component relative to the shear capacity of the flexural capacity, make these parts in the structure of the experience of the rarely met earthquake with enough assurance does not appear in the process of brittle shear failure. Should be paid attention to for the frame structure of the frame beam shear calculation and structure, make it meet the requirements of the relevant specification.



寿县合兴钢结构有限公司是专业从事安徽钢结构,合肥彩钢瓦,寿县钢结构,合肥钢结构公司

官方网站:http://www.sxhxgjg.com



最新内容:

版权所有:寿县合兴钢结构有限公司 合肥网络布线
电话:0554-4991161    手机:18175036696  13588259339

传真:0564-4991161  地址:寿县炎刘镇二环路与新桥大道路口向东100米 网站地图