Long-term performing aging steel infrastructures are to be preserved not only for the economic gain but also for its continued service to the society and as a live engineering model for the future. Life enhancement of these aging infrastructures through an effective restoration strategy is a major challenge for the engineering community all over the world. These structures were constructed purely on the basis of its static elastic response, predominantly under gravity load with some empirically deduced wind action. Concept of seismic action on the structure and its effect were completely absent in those days. In this context, development of effective strategy for restoration and up-gradation of these structures as per the modern guidelines require further research and study. This volume of work will show the Qualitative Seismic Vulnerability assessment of a 100 years old Steel Elevated water reservoir along with a Refined Methodology Flowchart for critical engineering evaluation of aging Steel structures.