钢结构与钢筋混凝土结构抗震优势比较.doc

钢结构与钢筋混凝土结构抗震优势比较

一、材料分析比较
“地震力”是惯性力，混凝土结构质量大，惯性力大；钢结构质量小，惯性小。所以在相同的地震作用下，混凝土结构受到很大的力，钢结构受到的力小。这是外因。
内因，钢结构材料强度高，耗能强，是延性材料，有屈服台阶，通过包络曲线来耗能。而混凝土是脆性材料！
钢结构所用的是钢材最低是用Q235，大部分的钢结构材料用的都是Q345。钢结构的阻尼比一般在0.01－0.02之间，钢筋混凝土结构的阻尼比一般在0.03－0.08之间。阻尼比小，在地震力作用下，变形大，因为钢结构韧性好，通过变形消耗地震能量，且容易恢复。钢结构较为柔软主要通过弹塑性变形吸收能量，较混凝土而言脆断的可能性低得多，一般认为10层以下的钢结构建筑物基本不会发生倒塌事故。

二、结构设计计算方式分析
钢结构采用弹性理论设计的，其构件能够在地震小幅度变形后再恢复；而钢筋混凝土结构是刚性理论设计的，不能变形，就不能吸收地震的能量。跨度越大越实惠，可回收，环保符合绿色建筑理念
由于钢材塑性、韧性好，可有较大变形，能很好地承受动力荷载，其次钢材匀质性和各向同性好，属理想弹性体，最符合一般工程力学的基本假定，因此，钢结构的抗震性能比钢筋混凝土结构的抗震性能好。
三、模型分析
荷载表格
2层梁恒载
2层楼板活荷载
2层楼板恒荷载
屋顶板活荷载
屋顶板横荷载

屋顶梁恒载
10KN/M2
3KN/M2
3KN/M2
3KN/M2
5KN/M2
5KN/M2

1、钢结构在荷载作用下的位移变形

2、混凝土在相同荷载作用下的位移变形

以上结构为钢结构和钢筋混凝土结构模型，两种结构在相同的荷载作用下，钢结构沿1、2、3轴的位移分别是0.00919mm、-0.00570 mm、-15746 mm。钢筋混凝土沿1、2、3轴的位移分别是0.00909mm、-0.00909 mm、-0.15255mm。从模型位移分析里看，加上钢结构震后快速恢复的特点，而混凝土结构属于刚性结构，变形后不可恢复原形，从而钢结构在抗震的方面要优于钢筋混凝土结构。

四、综合分析
从两种结构的材料分析和设计计算方式比较，模型分析比较，能很明确的知道钢结构建筑从抗震和结构稳定性来看，都优于钢筋混凝土结构建筑，这也是欧美发达国家50%以上的建筑为钢结构建筑的原因。

The Earthquake advantage of steel frame structure and concrete structure

1、The material analysis
Seismic force is the inertia force, the quality of concrete structures is biggest than steel frame structure ;so the inertia forces of concrete structures is biggest than the steel frame structures. in the same earthquake , concrete structure subject to considerable force , the steel structure is smaller . this is external reason .
steel frame structure have high strength steel materials , ductile materials, energy consumption is fast , yield steps is benefit to energy consumption . But Concrete structure
is a brittle material.
Steel structure with the minimum of steel Q235, most of the steel materials used are of Q345 . The steel structure of the damping ratio is generally between 0.01-0.02 , the damping of reinforced concrete structures than the average between 0.03-0.08 . The damping ratio smaller, the seismic force have large deformation , the steel toughness is good, the seismic energy consumption by deformation , so easy to restore . The steel structure is relatively soft ; absorb energy through elastic-plastic deformation than the concrete , the possibility of brittle fracture is much lower , generally below the 10-floor steel buildings do not collapse accident occurred .
2、The analysis comparison of two structural design calculations
Steel structure designed using the theory of elasticity；its components can recovery after earthquake deformation ，reinforced concrete structure is rigid design theory can not be deformed，it can not absorb the energy of the earthquake，so Span bigger and more affordable, recyclable , environmental protection and meet the green building concept。
Steel ductility, toughness , large deformation , can well withstand the dynamic loads，and Steel homogeneous and isotropic , is an ideal elastomer。Conform with basic assumption of the general engineering mechanics，so the seismic performance of steel structures is better than concrete structures .

3、Structural model analysis
Load form
first floor beam dead load
first floor slab Live load
first floor slab dead load
roof floor slab live load
roof slab dead load
roof beam dead load
10KN/M2
3KN/M2
3KN/M2
3KN/M2
5KN/M2
5KN/M2

（1）、Displacement deformation of the steel structure in the loads

（2）、Displacement deformation of the concrete structure in the same loads

The above structure of steel and reinforced concrete structural model。Two structures in the same loads，The steel structure along the 1,2,3 axis displacement is：0.00919mm、-0.00570 mm、-15746 mm。Reinforced concrete along the 1,2,3 axis displacement is 0.00909mm、-0.00909 mm、-0.15255mm。the displacement analysis from the model analysis ，and the characteristics of fast recovery in the steel structure after the earthquake，the concrete structure is a rigid structure ，deformation can not restore after the prototype ，steel structures is superior to reinforced concrete structure in seismic areas。

4、A comprehensive analysis
Materials analysis and design method of calculation， model analysis and comparison ， the two structures is very clear that we know the steel construction of seismic and structural stability , superior to reinforced concrete structures , which is the developed countries in Europe and the United States more than 50 percent of the construction of steel 。that is reason.