Existing subsoil conditions can have substantial impacts on the acquisition of real estate, design and construction of buildings and impervious spaces. Builders will need to tackle building projects with subsoil challenges. Thorough soil investigation, proper design and construction procedures, will greatly reduce the ailing effects of long term differential settlement.
Built in 1173 and prior to the restoration work performed between 1990 and 2001, the Tower of Pisa leaned at an angle of 5.5 degrees. Today the top of tower is displaced 3.9 meters (12’-10”). 714 years later Gustave Eiffel tackled his subsoil challenges with triumphant results.
See the article here.