Why Do Structure Fail?

The design of structures should satisfy three fundamental requirements: 1) Stability: The structure should be stable under the action of loads. 2) Strength: The structure should resist safely stresses induced by the loads. 3) Serviceability: The structure should perform satisfactorily under service loads. Defective construction that causes failure may be due to numerous reasons that may not be easy to predict before or during the construction. The major causes of structural failure are defective designs that have not determined the actual loading conditions on the structural elements. Inferior construction materials may also be the cause since the loads are calculated for materials of specific characteristics. Structure may fail even if the design is satisfactory, but the materials are not able to withstand the loads. Employment of unskilled labor on construction work is another reason for structural failures. Reducing failures of buildings and other structures requires competent design; clear communication of that design to the contractor by means of engineering drawings, etc.; careful and competent construction; and effective construction supervision. Therefore, it is important that the owners, designers, and builders are fully conscious of the reasons of failure, and undertake all preventive measures. Stability, strength and serviceability can only be achieved by following basic design principles. This paper presents some cases of different structural failures and the preventions, so other engineers can benefit from this knowledge.