第一章绪论版.ppt

Hydropolis, the worlds first underwater hotel. Entirely built in Germany and then assembled in Dubai , it is scheduled to be completed by 2009 after many delays. The Burj Dubai. Construction began in 2005 and is expected to be complete by 2008. At an estimated height of over 800 meters, it will easily be worlds tallest building when finished. It will be almost 40 percent talle r than the current tallest building, the Yaipei 101. This is what downtown Dubai will look like around 2008-2009. More than 140 stories of the Burj Dubai have alr eady been completed. It is already the worlds tallest man made structure and it is still not scheduled to be completed for at least another year. The Al Burj. This will be the centerpiece of the Dubai Waterfront. Once completed it will take over the title of the tallest structure in the world from the Burj Dubai. Recently it was announced that the final height of this tower will be 1200 meters. That would make it more than 30 percent taller than the Burj Dubai and three times as tall as the Empire State Building . The Burj al Alam, or The World Tower . Upon completion it will rank as the worlds highest hotel. It is expected to be finished by 2009. At 480 meters it will only be 28 meters shorter than the Taipei 101.  The Trump International Hotel Tower, which will be the centerpiece of one of the palm islands, The Palm Jumeirah. 1绪论1. 2 钢结构的特点(通过8个小问题掌握） (1) 强度高、塑性好、韧性好 问题１：比较钢材（Q235钢）和C80混凝土的抗 　　　　压和抗拉强度设计值。 　　　　215N/mm2; 50.2N/mm2, 3.11N/mm2 问题２：比较钢材（Q235钢）和C80混凝土的弹性 　　　　模量。（206E3N/mm2; 38E3N/mm2) 问题３：钢材塑性好赋予钢结构的特性是什么？ 问题4： 钢材韧性好赋予钢结构的特性是什么？ 1绪论1. 2 钢结构的特点 (2)钢结构的重量轻 问题5：钢材容重大，强度高，做成的结构却比较轻？ 质量密度ρ和强度?的比值α来衡量 ， α值越小，结构相对越轻。建筑钢材的值等于1.7~3.7×10-4/m；木材为5.4×10-4/m；钢筋混凝土约为18×10-4/m。以同样跨度承受同样的荷载，钢屋架的重量最多不过为钢筋混凝土屋架的1/3~1/4，冷弯薄壁型钢屋架甚至接近于1/10。 重量轻，可减轻基础的负荷，降低地基、基础部分的造价，同时还方便运输和吊装。 1绪论1. 2 钢结构的特点 (3)材质均匀 问题6：钢材材质均匀赋予钢结构设计的 特点是什么？ 钢材由于冶炼和轧制过程的科学控制，其组织比较均匀，接近各同向性，为理想的弹性-塑性体，其弹性模量和韧性模量皆较大，因此，钢结构实际受力情况和工程力学计算