本文關(guān)鍵詞： 預(yù)應(yīng)力混凝土梁 現(xiàn)存應(yīng)力 應(yīng)力釋放 新型切槽法 液壓千斤頂　出處：《廣西科技大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：預(yù)應(yīng)力混凝土結(jié)構(gòu)廣泛應(yīng)用于現(xiàn)代工程建設(shè)中,在其施工、運(yùn)營(yíng)過(guò)程中,因預(yù)應(yīng)力施工工藝、材料收縮與徐變等因素的影響,預(yù)應(yīng)力不可避免地發(fā)生損失,預(yù)應(yīng)力損失的大小約為10%~20%。隨著運(yùn)營(yíng)時(shí)間的增長(zhǎng),在自然環(huán)境及荷載作用的影響下,預(yù)應(yīng)力混凝土結(jié)構(gòu)難免會(huì)產(chǎn)生病害,需要維修加固。另外,一些預(yù)應(yīng)力混凝土結(jié)構(gòu),隨著荷載的不斷增加,常常也需要結(jié)構(gòu)增強(qiáng)。預(yù)應(yīng)力混凝土結(jié)構(gòu)的維修加固與增強(qiáng),首先需要確定現(xiàn)役結(jié)構(gòu)的狀態(tài),現(xiàn)存預(yù)應(yīng)力是一個(gè)重要的指標(biāo)。由于預(yù)應(yīng)力混凝土結(jié)構(gòu)自身應(yīng)力狀態(tài)的復(fù)雜性,其現(xiàn)存應(yīng)力的測(cè)量十分困難。預(yù)應(yīng)力混凝土結(jié)構(gòu)現(xiàn)存應(yīng)力的測(cè)量一直是業(yè)內(nèi)研究的熱點(diǎn),更是難點(diǎn)。對(duì)于預(yù)應(yīng)力混凝土結(jié)構(gòu)現(xiàn)存應(yīng)力的測(cè)量,目前使用最廣泛的方法仍然是應(yīng)力釋放法,本文研究的新型切槽法就是在應(yīng)力釋放法的基礎(chǔ)上加以改進(jìn)而得到的。本文主要研究?jī)?nèi)容有:(1)在總結(jié)既有應(yīng)力釋放法的基礎(chǔ)上,提出了扁型液壓千斤頂技術(shù)與應(yīng)力釋放法相結(jié)合的新型切槽法測(cè)量技術(shù)。為了消除以往運(yùn)用應(yīng)力釋放法測(cè)量預(yù)應(yīng)力混凝土結(jié)構(gòu)現(xiàn)存應(yīng)力中混凝土彈性模量的不確定性,將扁型液壓千斤頂技術(shù)與應(yīng)力釋放法相結(jié)合,研究了新型切槽應(yīng)力釋放法的測(cè)試?yán)碚?推導(dǎo)了有關(guān)計(jì)算公式,研制了對(duì)應(yīng)的測(cè)試系統(tǒng)。(2)以混凝土梁模型為樣本進(jìn)行了實(shí)體試驗(yàn)研究。在梁體上切割出啞鈴狀槽孔,運(yùn)用新型切槽法技術(shù)對(duì)該梁的現(xiàn)存應(yīng)力值進(jìn)行測(cè)量,通過(guò)實(shí)驗(yàn)值與理論值的對(duì)比分析,驗(yàn)證了新型切槽法這一技術(shù)的可行性,并對(duì)測(cè)量過(guò)程進(jìn)行了詳細(xì)研究。(3)應(yīng)力釋放測(cè)量為點(diǎn)測(cè)量,工程的結(jié)構(gòu)為連續(xù)體結(jié)構(gòu)。以測(cè)點(diǎn)應(yīng)力描述實(shí)體的應(yīng)力狀態(tài),需要合理選擇測(cè)點(diǎn)布置,并研究非均勻介質(zhì)中測(cè)點(diǎn)周圍狀態(tài)對(duì)測(cè)量結(jié)果的影響。本文采用有限元軟件ANSYS建立預(yù)應(yīng)力混凝土箱梁模型,通過(guò)有限元仿真模擬分析了測(cè)點(diǎn)的選取、槽孔尺寸、預(yù)應(yīng)力筋布置等因素對(duì)新型切槽法測(cè)量可能造成的影響,目的是提高該測(cè)量方法的精度,使其成為更有效的測(cè)量方法。
[Abstract]:Prestressed concrete structure is widely used in modern engineering construction. In the process of construction and operation, due to the influence of prestress construction technology, material shrinkage and creep, prestressing force will inevitably lose. The size of the prestress loss is about 10% 20%. With the increase of operating time, under the influence of natural environment and load, the prestressed concrete structure will inevitably produce diseases and need to be repaired and strengthened. In addition, some prestressed concrete structures, With the increasing of load, it is often necessary to strengthen the structure. In order to strengthen and maintain the prestressed concrete structure, it is necessary to determine the state of the existing structure. The existing prestress is an important index. Because of the complexity of the stress state of the prestressed concrete structure, it is very difficult to measure the existing stress. The measurement of the existing stress of the prestressed concrete structure has always been a hot spot in the field of research. It is even more difficult. The most widely used method for measuring the existing stresses of prestressed concrete structures is still the stress release method. The new groove cutting method studied in this paper is improved on the basis of stress release method. The main content of this paper is: 1) on the basis of summing up the existing stress release method, In order to eliminate the uncertainty of the existing stress measurement of prestressed concrete structures, a new method of groove cutting is proposed, which combines flat hydraulic Jack technique and stress release method. Based on the combination of flat hydraulic Jack technology and stress release method, the test theory of the new groove cutting stress release method is studied, and the relevant calculation formulas are derived. The concrete beam model is used as the sample to carry out the solid test study. The dumbbell groove is cut on the beam body, and the existing stress value of the beam is measured by using the new groove cutting technique. By comparing the experimental and theoretical values, the feasibility of the new notch cutting method is verified, and the measurement process is studied in detail. The stress release measurement is a point measurement. The structure of the project is a continuum structure. In order to describe the stress state of the entity by measuring point stress, it is necessary to select the measuring point arrangement reasonably. In this paper, the finite element software ANSYS is used to establish the model of prestressed concrete box girder, and the selection of measuring point and the size of slot are analyzed by finite element simulation. The possible influence of prestressing tendons arrangement on the new method is to improve the accuracy of the method and make it a more effective measurement method.
【學(xué)位授予單位】：廣西科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU378.2

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本文編號(hào)：1522957