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王利恒¹，  周錫元²，  閻維明²，  涂  鳴²
（1 北京長(zhǎng)城計(jì)量測(cè)試技術(shù)研究所重點(diǎn)實(shí)驗(yàn)室，北京 100095； 2 北京工業(yè)大學(xué)工程抗震與結(jié)構(gòu)診治北京市重點(diǎn)實(shí)驗(yàn)室，北京100124）

[摘要] 對(duì)無(wú)粘結(jié)預(yù)應(yīng)力鋼筋混凝土簡(jiǎn)支梁，分11級(jí)損傷加載直到結(jié)構(gòu)達(dá)到極限承載能力狀態(tài)。在每一級(jí)損傷狀態(tài)下，對(duì)結(jié)構(gòu)進(jìn)行了錘擊試驗(yàn)與共振試驗(yàn)。對(duì)錘擊試驗(yàn)結(jié)構(gòu)跨巾位移響應(yīng)進(jìn)行時(shí)頻分析以及就共振試驗(yàn)通過(guò)找共振峰的方法都可以得到結(jié)構(gòu)的振幅與頻率關(guān)系。進(jìn)一步將二者結(jié)合起來(lái)，通過(guò)分析得到了合適的時(shí)頻分析所用窗口寬度。再結(jié)合時(shí)頻分析方法，分析得到各級(jí)加載后無(wú)粘結(jié)預(yù)應(yīng)力鋼筋混凝土梁振幅與頻率關(guān)系曲線族。通過(guò)分析結(jié)構(gòu)振幅與頻率關(guān)系曲線族的特點(diǎn)，總結(jié)了各級(jí)損傷狀態(tài)下結(jié)構(gòu)的非線性動(dòng)力特性并分析了用無(wú)粘結(jié)預(yù)應(yīng)力鋼筋混凝土梁的非線性動(dòng)力特性做損傷檢測(cè)的可行性。
[關(guān)鍵詞] 無(wú)粘結(jié)預(yù)應(yīng)力；時(shí)頻分析；非線性動(dòng)力特性；損傷檢測(cè)；試驗(yàn)

Study on nonlinear dynamic characteristics of unbonded prestressed reinforced concrete beam
Wang Liheng1， Zhou Xiyuan2， Yan Weiming2， Tu Ming2
(1 Changcheng Institute of Metrology & Measurement, State Key Lab for Metrology and Catibration, Beijing 100095,C hina; 2 Municipal Key Lab. of Earthquake Engin. and Stru. Retrofit, Beijing Univ. of Tech.，Beijing 100124,China)

Abstract: For an unbonded prestressed reinfcrced concrete simply suppcrted beam, eleven load levels are designed until it reaches ultimate bearingcapabilities. At each damage level, impact excitation vibration tests and harmonic excitation vibration tests are conducted. The time-frequency analysis of structural midspan displacement responses of impact excitation vibration tests is carried out, as well as the relationship of structural displacement amplitude and its fundamental frequency is obtained. By combining the results of the time-frequency analysis with the results of the hannonic excitation vibration tests, reasonable window width for time-frequency analysis can he obtained. Using time-frequency analysis, the group of curves of structural displacement amplitude and its fundamental frequency at each impairing level can he obtained. By analyzhg the characteristics of the group of curves of the stuctural displacement amplitude and its funclamental frequency, the nonlinear dynamic characteristics of the impairing unbonded prestressed reinforcd concrete beam are drawn. Then the possibilities of using nonlinear dynamic characteristics to detect the damage levels of the unbonded prastressed reinforced concrete beam are discussed.
Keywords: unbonded torestressed; time-frequency analysis; nonlinear dynamic characteristic; damage detection; test