As I go thinking upon how are those infrastructures in our city was built to last I stumble upon a question. How do they calculate the security of it to assure the occupants of a safe stay inside the particular building? I was just interested to know more about this because I have seen a lot of disasters relating to buildings and other structure that we usually go due to our needs of service. Just like the disaster happened maybe last month in the other town nearest to us. It was an ongoing project which will soon rise as a mall but the process killed five construction workers because a wall lose its strength was fell down to the area and massively killed five poor workers. Now, this is the question of my interest and I was so much hopeful to get several advices or answers for this.