本文選題：超高性能混凝土 + HRB500　； 參考：《北京工業(yè)大學(xué)》2015年博士論文

【摘要】：超高性能混凝土(Ultra High Performance Concrete,簡(jiǎn)稱UHPC)是一種新型水泥基復(fù)合材料,具有較高的力學(xué)性能和良好的耐久性,在土木工程領(lǐng)域具有廣闊的應(yīng)用前景,然而目前對(duì)其結(jié)構(gòu)受力性能缺乏足夠的研究。HRB500級(jí)鋼筋是一種新型熱軋帶肋鋼筋,具有較高的強(qiáng)度和良好的延性,工程中采用HRB500鋼筋具有節(jié)省鋼筋用量、方便鋼筋布置等優(yōu)點(diǎn)。將UHPC和HRB500鋼筋結(jié)合起來(lái),可以充分發(fā)揮二者的優(yōu)良性能,達(dá)到減輕混凝土結(jié)構(gòu)的自重、簡(jiǎn)化鋼筋布置、增大結(jié)構(gòu)跨越能力、增加結(jié)構(gòu)耐久性的目的。本文對(duì)HRB500鋼筋UHPC梁進(jìn)行了系列試驗(yàn)研究和理論分析,探討了HRB500鋼筋和UHPC材料的適配性,對(duì)UHPC梁的受力性能和設(shè)計(jì)計(jì)算理論進(jìn)行了研究。主要研究?jī)?nèi)容如下:(1)完成了UHPC抗壓強(qiáng)度、抗拉強(qiáng)度、抗折強(qiáng)度等基本力學(xué)性能試驗(yàn),分析了養(yǎng)護(hù)方法、振搗方法對(duì)UHPC基本力學(xué)性能的影響,獲得了UHPC軸心受壓應(yīng)力—應(yīng)變關(guān)系曲線的上升段,并擬合了軸心受壓應(yīng)力—應(yīng)變曲線上升段的方程。試驗(yàn)表明:UHPC的峰值壓應(yīng)力對(duì)應(yīng)的壓應(yīng)變遠(yuǎn)高于普通混凝土,接近3000×10-6。UHPC開裂后裂縫間的鋼纖維承擔(dān)拉應(yīng)力,軸拉應(yīng)力隨裂縫寬度的增大和裂縫間鋼纖維的拔出而逐漸減小。(2)完成了6根后張法預(yù)應(yīng)力UHPC簡(jiǎn)支梁的抗彎性能試驗(yàn)。對(duì)試驗(yàn)梁的受力過程、裂縫分布形態(tài)及發(fā)展情況、荷載—撓度曲線特征以及破壞模式進(jìn)行了詳細(xì)的闡述和分析。試驗(yàn)表明:HRB500鋼筋與UHPC梁適配良好,UHPC梁彎曲裂縫細(xì)而密,正常使用極限狀態(tài)下試驗(yàn)梁最大裂縫寬度不大于0.15mm,試驗(yàn)梁位移延性系數(shù)均大于3。根據(jù)試驗(yàn)建議了UHPC軸拉及軸壓應(yīng)力-應(yīng)變關(guān)系曲線并給出了相應(yīng)的方程;計(jì)算UHPC梁開裂彎矩時(shí),考慮鋼纖維對(duì)受拉區(qū)塑性發(fā)展程度的增強(qiáng)作用,引入抗裂修正系數(shù)對(duì)《預(yù)應(yīng)力及鋼筋混凝土橋涵設(shè)計(jì)規(guī)范》(JTG D62-2004)中開裂彎矩計(jì)算公式進(jìn)行了修正,修正后計(jì)算結(jié)果與試驗(yàn)值吻合較好。計(jì)算裂縫寬度時(shí),考慮鋼纖維的增韌阻裂作用,引入裂縫修正系數(shù)對(duì)《混凝土結(jié)構(gòu)設(shè)計(jì)規(guī)范》(GB50010-2010)中計(jì)算最大裂縫寬度的公式進(jìn)行了修正,修正后計(jì)算值與試驗(yàn)值吻合良好;建立了UHPC梁極限承載力計(jì)算公式,理論計(jì)算值與試驗(yàn)值吻合良好,可作為UHPC梁理論分析和設(shè)計(jì)的參考。(3)完成了9根UHPC梁的抗剪性能試驗(yàn)研究。試驗(yàn)表明:隨剪跨比的增大,試驗(yàn)梁破壞形式從斜壓破壞逐漸轉(zhuǎn)向剪壓破壞、斜拉破壞;受剪斜裂縫細(xì)而密,正常使用極限狀態(tài)下最大斜裂縫寬度不大于0.2mm;HRB500鋼筋作箍筋時(shí),其高強(qiáng)性能可以得到充分發(fā)揮;影響抗剪承載力的主要因素包括剪跨比、預(yù)加力、配箍率等。根據(jù)UHPC梁抗剪試驗(yàn)推導(dǎo)了UHPC梁開裂剪力和正常使用極限狀態(tài)下最大斜裂縫寬度的計(jì)算公式;利用現(xiàn)有規(guī)范對(duì)UHPC的抗剪承載力進(jìn)行了計(jì)算,計(jì)算結(jié)果表明現(xiàn)有規(guī)范計(jì)算結(jié)果過于保守;在修正壓力場(chǎng)理論的基礎(chǔ)上,考慮梁上部受壓區(qū)混凝土和下部受拉區(qū)骨料咬合力、鋼纖維有效拉力及箍筋共同提供抗剪承載力,推導(dǎo)了UHPC梁的抗剪承載力計(jì)算方法,并給出了簡(jiǎn)化的顯示表達(dá)式,與本文試驗(yàn)的結(jié)果比較表明,采用該方法計(jì)算的抗剪承載力與試驗(yàn)結(jié)果吻合良好;最后考慮剪跨比、配箍率、預(yù)加力因素建立了超高性能混凝土梁的抗剪承載力的統(tǒng)計(jì)計(jì)算公式,計(jì)算值與試驗(yàn)值吻合較好,且變異系數(shù)較小。(4)為研究超高性能混凝土連續(xù)梁的內(nèi)力重分布問題,利用非線性分析方法編制了計(jì)算彎矩調(diào)幅系數(shù)的計(jì)算程序。通過對(duì)22根HRB500鋼筋超高性能混凝土連續(xù)梁的數(shù)值分析,得到了22根模擬梁在跨中集中荷載作用下達(dá)到極限承載力時(shí)的彎矩調(diào)幅系數(shù),擬合了以截面相對(duì)受壓區(qū)高度為自變量的彎矩調(diào)幅系數(shù)計(jì)算公式;最后以滿足正常使用極限狀態(tài)下最大裂縫寬度不大于0.2mm為條件,建議了HRB500鋼筋超高性能混凝土梁的彎矩調(diào)幅系數(shù)取值方法。
[Abstract]:Ultra High Performance Concrete (UHPC) is a new type of cement based composite material. It has high mechanical properties and good durability. It has a broad application prospect in the field of civil engineering. However, the lack of sufficient research on the mechanical properties of its structure is a new type of hot rolled strip. Ribbed reinforcing bar, with high strength and good ductility, HRB500 steel has the advantages of saving steel and reinforcing bar arrangement in engineering. Combining UHPC and HRB500 steel, the excellent performance of two people can be fully played to reduce the weight of concrete structure, simplify the arrangement of steel bar, increase the structure leaping ability and increase the structure. The purpose of durability is to carry out a series of experimental research and theoretical analysis on HRB500 reinforced UHPC beams. The compatibility of HRB500 steel and UHPC materials is discussed. The stress performance and design calculation theory of UHPC beams are studied. The main contents are as follows: (1) the basic mechanical properties of UHPC, tensile strength, tensile strength and flexural strength have been completed. The effect of the curing method and vibration method on the basic mechanical properties of UHPC is analyzed. The rise section of the stress-strain relationship curve of the UHPC axle center is obtained, and the equation of the rising section of the axial compression stress-strain curve is fitted. The test shows that the compressive strain of the peak pressure stress on the UHPC is far higher than that of the ordinary concrete, close to 3000 x 10-6. The tensile stress of the steel fibers between cracks after.UHPC cracking, the axial tensile stress as the crack width increases and the steel fiber pullout between the cracks gradually decreases. (2) the flexural performance test of 6 post tensioned prestressed simple supported beams is completed. The stress process, the distribution and development of the crack, the load deflection curve and the characteristics of the load deflection curve of the test beam are made. The failure mode is elaborated and analyzed in detail. The test shows that the HRB500 bar is well suited to the UHPC beam, the bending crack of the UHPC beam is fine and dense. The maximum crack width of the test beam is not more than 0.15mm under the normal use limit state, and the displacement ductility coefficient of the test beam is more than 3.. The stress strain relationship curve of the axial tension and axial compression of the UHPC axis is proposed. The corresponding equation is given. When calculating the cracking moment of UHPC beam, considering the strengthening effect of steel fiber on the plastic development of the tensile zone, the formula of cracking bending moment in the code for design of "prestressed and reinforced concrete bridge and culvert" (JTG D62-2004) is amended by introducing the crack resistance correction coefficient, and the calculation results are in good agreement with the experimental values. In the crack width, considering the toughening and resistance cracking of steel fiber, the formula for calculating the maximum crack width in the design code for concrete structure (GB50010-2010) is amended by introducing the fracture correction coefficient, and the calculated value is in good agreement with the test value, and the formula of ultimate bearing capacity of the UHPC beam is established, the theoretical calculation value is in good agreement with the test value. Well, it can be used as a reference for the theoretical analysis and design of UHPC beams. (3) the experimental study on the shear performance of 9 UHPC beams has been completed. The test shows that the failure form of the test beam is gradually turned from baroclinic failure to shear stress failure, slanting failure, slanting cracks are fine and dense with the increase of shear span ratio, and the maximum slanting crack width is not more than 0.2mm under the normal use limit state. When HRB500 steel is used as stirrup, its high strength performance can be brought into full play. The main factors affecting the shear bearing capacity include the shear span ratio, the preloading force, the stirrup rate and so on. According to the shear test of the UHPC beam, the calculation formula of the cracking shear force of the UHPC beam and the maximum slanting crack width under the normal use limit state is derived. The shear bearing capacity of the existing standard on the shear bearing capacity of the UHPC is used. The load is calculated, and the calculation results show that the existing standard calculation results are too conservative. On the basis of the modified pressure field theory, the shear bearing capacity of the concrete and the lower part of the tensile zone in the upper part of the beam is considered, the effective tensile force and the stirrup of the steel fiber are jointly provided, and the calculation method of the shear bearing capacity of the UHPC beam is derived, and the calculation method of the shear bearing capacity of the beam is derived. The simplified display expression is compared with the results of the experiment in this paper. It shows that the shear bearing capacity calculated by this method is in good agreement with the test results. Finally, a statistical formula for calculating the shear bearing capacity of super high performance concrete beams is established by considering the shear span ratio, the stirrup rate and the preloading factors. The calculated values are in good agreement with the experimental values and the variation coefficients are in good agreement. (4) (4) in order to study the internal force redistribution of the continuous beam of super high performance concrete, a calculation program for calculating the amplitude coefficient of bending moment is developed by using the nonlinear analysis method. Through the numerical analysis of 22 HRB500 reinforced concrete continuous beams, the ultimate bearing capacity of 22 simulated beams under the central load of the middle span is obtained. The amplitude modulation coefficient of the bending moment is fitted to the formula of the moment modulation coefficient of the bending moment with the height of the section relative to the compression zone as the independent variable. Finally, the method of the moment adjustment coefficient of the bending moment of the HRB500 reinforced concrete beam is proposed to satisfy the condition that the maximum crack width is not more than 0.2mm under the normal operating limit state.
【學(xué)位授予單位】：北京工業(yè)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU378.2

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 趙順波,趙國(guó)藩,黃承逵;預(yù)應(yīng)力鋼纖維混凝土梁斜裂縫寬度計(jì)算[J];大連理工大學(xué)學(xué)報(bào);1998年06期

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本文編號(hào)：1988785