Reliability & Durability
Structural reliability is often evaluated using probabilistic-based methods since variations can occur in the loading, material behavior, and composite structural performance over time. The intent is to establish the probability that a structural condition could develop and then evaluate the risk relative to the cost for prevention. One application of these methods is life-cycle costing, which determines the optimal time for replacement of structures or components rather than continued maintenance costs and operational safety risk.
Fatigue Cracking at Welded Connections
ANATECH has performed analyses to determine the fatigue cracking performance of welded connections in hydraulic steel structures. These analyses use global modeling to determine the cyclic demands on the welded joint, local modeling to establish the residual stress distributions due to welding, and then evaluate the fatigue growth of cracks under cyclic loading. This methodology has been incorporated into U. S. Army Corp of Engineers Guidance for ETL 1110-2-556, “Advanced Reliability Analysis of Fatigue Cracking in Horizontally Framed Miter Gates.”
Aging and Degradation of Concrete and Steel Structures
With considerable experience in assessing the long-term structural performance of aging concrete structures, ANATECH is able to evaluate the causes and solutions for structures suffering from degradation due to Alkaline Aggregate Interaction (AAR) and also excessive cracking and deterioration due to thermal cycling and freeze-thaw cycles.
Structural Risk and Life Cycle Management
ANATECH provides engineering and analytical support for assessing structural risk and for life cycle management. This work generally involves assessments and cost analysis which evaluates the long-term performance and need for continual maintenance of aging infrastructure versus the cost for replacement or major structural rehabilitation in order to optimize the cost benefits for customers.
Probabilistic Assessments
For systems with variable or uncertain characteristics, ANATECH has experience in providing probabilistic-based structural assessments to determine structural risks and reliability. Some examples are structural risk from internal cracking in dam monoliths as a function of pool elevations and seismic hazard, structural reliability for fatigue cracking, durability of aging concrete monoliths exhibiting significant cracking distress.
