Damage assessment and diagnosis of hydraulic concrete structures using optimization-based machine learning technology

Concrete is widely used in various large construction projects owing to its high durability,compressive strength,and plasticity.However,the tensile strength of concrete is low,and concrete cracks easily.Changes in the concrete structure will result in changes in parameters such as the frequency mode and curvature mode,which allows one to effectively locate and evaluate structural damages.In this study,the characteristics of the curvature modes in concrete structures are analyzed and a method to obtain the curvature modes based on the strain and displacement modes is proposed.Subsequently,various indices for the damage diagnosis of concrete structures based on the curvature mode are introduced.A damage assessment method for concrete structures is established using an artificial bee colony backpropagation neural network algorithm.The proposed damage assessment method for dam concrete structures comprises various modal parameters,such as curvature and frequency.The feasibility and accuracy of the model are evaluated based on a case study of a concrete gravity dam.The results show that the damage assessment model can accurately evaluate the damage degree of concrete structures with a maximum error of less than 2%,which is within the required accuracy range of damage identification and assessment for most concrete structures.

BIM-based framework of automatic tunnel segment assembly and deviation control

The design of universal segments and deviation control of segment assembly are essential for robust and low-risk tunnel construction.A building information modeling(BIM)-based framework was proposed for parametric modeling,automatic assembly,and deviation control of universal segments.First,segment models of different levels of detail(LoDs)were built based on BIM visual programming language(VPL)for different project life cycles.Then,the geometric constraints,requirements,and procedures for parametric segment assembly were distilled to develop a program that combines a novel typesetting algorithm with a 3D path replanning algorithm.Typesetting is implemented by introducing a point indication matrix,characterizing segments by sides,and manipulating geometries in a VPL.Simultaneously,3D path replanning,with non-uniform rational B-splines(NURBS)and arcs as basic shapes,was used to resolve unacceptable deviation situations after typesetting.Finally,the proposed framework was validated on a water diversion line and was found to be more effective and accurate than the previous method.