Damage Identification Based on Dead
Load Redistribution: Methodology
Harry W. Shenton III, A.M.ASCE1; and Xiaofeng Hu2
Abstract: A new method for damage identification in large, massive civil structures is presented, which is based on the idea that dead load is redistributed when damage occurs in the structure. The method uses static strain measurements due to dead load only as input to the identification procedure. An analytical model of a fixed-fixed beam is developed in which the damage is represented by a section of reduced flexural rigidity. The damage state is determined by the location, length, and severity of the stiffness reduction. A forward analysis of the beam response is first presented to illustrate how the dead load is redistributed for different damage scenarios. The inverse problem is defined by a constrained optimization problem and is solved using a genetic algorithm. The proposed method correctly identified damage in the beam for a wide range of locations and damage severities. The identification procedure, in general, has a greater degree of success with increasing damage severity. Results show that damage is difficult to identify when it is close to the inflection point of theundamaged beam, where the dead load strain is zero. The effect of measurement noise on the ability to identify damage is investigated in the companion paper.
在恒載作用下破壞時的再分配的方法論

Harry W. Shenton III, A.M.ASCE1; and Xiaofeng Hu2

摘要: 這是一種研究目前的民用建筑在恒載作用下如何識別結(jié)構(gòu)大規(guī)模破壞的新方法。由于靜荷載唯一的被輸入到識別程序里，所以這種方法用于靜應(yīng)變測量。一種確定固定梁的解析模型出現(xiàn)在由截面抗彎剛度減少而產(chǎn)生破壞的地方。這種破壞狀態(tài)由位置、長度，和迅速降低的強(qiáng)度來確定的。 一個關(guān)于橫梁反應(yīng)的前沿分析首先被用來闡明不同的破壞方案如何導(dǎo)致靜荷載再重心分布的。 那相反的問題是放寬約束條件并利用一幾何算法來解決。 建議方法正確地識別由于大范圍強(qiáng)度破壞而導(dǎo)致梁的破壞。 通常這個識別程序在強(qiáng)度破壞增加時有一個較大的可信度。結(jié)果表明當(dāng)它接近未破壞梁的彎曲點(diǎn)時破壞很難識別，這個彎曲點(diǎn)就是在靜荷載應(yīng)力為零的地方。 識別破壞能力不同觀點(diǎn)的影響效果正在進(jìn)行問卷中