重复荷载下高强钢筋与混凝土黏结性能的试验研究

牟晓光^1,2 王清湘¹ 司炳君¹
（1. 大连理工大学海岸和近海工程国家重点实验室，辽宁大连 116024；
2. 中交公路规划设计院，北京 100010）

摘要：随着预应力钢筋强度的提高及钢筋外形的变化，加之抗震设计必须考虑的黏结退化，钢筋与混凝土之间的黏结锚固问题愈显突出。通过光圆钢棒、异形钢棒和螺旋肋钢丝拉拔试件在重复荷载作用下的拔出试验，比较了3种不同外形高强预应力钢筋的黏结特性，研究了螺旋状预应力钢筋与混凝土界面间的黏结锚固机理，并讨论了影响黏结锚固性能的主要因素。根据试验结果，给出3种高强预应力钢筋在等幅重复荷载作用下的特征荷载值与应力水平上限的关系式。结果表明光圆钢棒在重复荷载作用下与混凝土的黏结性能较差；而异形钢棒和螺旋肋钢丝具有较好的黏结性能，且螺旋肋钢丝的黏结性能优于异形钢棒。研究成果为承受重复荷载的此种高强预应力钢筋混凝土结构的设计提供了依据。
关键词：重复荷载；黏结机理；高强钢筋；刚度；滑移量

An experimental study of the bonding behavior between high-strength
steel bar and concrete under repeated loadings

Mou Xiaoguang^1,2 Wang Qingxiang¹ Si Bingjun¹
(1. State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, China; 2. China Highway Planning and Design Institute Consultants, INC., Beijing 100010, China)

Abstract: With the improvement in prestressing tendon strength, variations in deformation patterns of rebars, and the necessity of bond deterioration in earthquake-resistant designs, the bond anchorage between reinforcement and concrete has become an increasingly acute issue. The pullout specimens of round steel bars, deformed steel bars and helical rib steel wires were tested under repeated loadings. Bond behaviors of the interfaces between 3 surface patterns of prestressing tendons and concrete were compared, the bond mechanisms between the helical prestressing tendons and concrete were explained, and the main influencing factors on bond anchorage performance were discussed. Based on the experimental results, the relationships between characteristic loads and maximum stress levels were obtained under repeated constant-amplitude loadings. The results indicate that the bond between round steel bars and concrete under repeated loadings is weak, whereas the bond for deformed steel bars is better and that for helical rib steel wires is the best.
Keywords: repeated loading; bond mechanism; high-strength steel bar; rigidity; slippage
E-mail: mxg0124@yahoo.com.cn

高温下1770级φ^P5钢丝蠕变及应力松弛性能试验研究

张昊宇 郑文忠
（哈尔滨工业大学，黑龙江哈尔滨150090）

摘要：鉴于高温下预应力钢丝蠕变、应力松弛及温度膨胀性能是影响预应力结构抗火性能的重要因素，以1770级低松弛预应力钢丝为对象开展了研究工作。完成了25个钢丝试件的高温蠕变试验，得到钢丝高温蠕变应变与时间的关系曲线，建立起钢丝高温蠕变应变计算公式，揭示出蠕变应变随温度升高、应力水平增长及蠕变时间延长而增大的规律；提出考虑高温蠕变影响的钢丝持久极限强度计算公式，揭示了高温下钢丝持久强度与高温下极限强度的差值随温度升高而增大的规律。完成了26个钢丝试件的高温下应力松弛试验，得到高温下钢丝应力松弛与时间的关系曲线，建立高温下钢丝应力松弛的计算公式，揭示了钢丝初应力越大，所受温度越高，松弛时间越长，应力松弛值越大的规律。完成1个钢丝试件的高温下温度膨胀试验，得到钢丝膨胀应变随温度升高而增长的规律，初步提出钢丝高温膨胀应变计算公式。
关键词：预应力钢丝；高温；蠕变；应力松弛；膨胀

An experimental study on the creep and stress relaxation properties of 1770-φ^P5 prestressing steel wires at high temperatures

Zhang Haoyu Zheng Wenzhong
(Harbin Institute of Technology, Harbin 150090, China)

Abstract: In view of the fact that creep, stress relaxation and thermal expansion are key factors on the fire resistance characteristics of prestressed structures, prestressing steel wires(standard tensile strength fptk=1770N/mm2, low relaxation of prestress)are selected to study these factors. Creep experiments at high temperatures on 25 steel wires are carried out. Curves of creep strain and time are obtained and the creep strain model is established. It is found that creep strain will increase when any of the three factors(temperature, initial stress and time)increases. Endurance limit with creep strain at high temperatures is also presented, which shows that the difference between endurance limit and tensile strength limit increases when temperature increases. Stress relaxation experiments at high temperatures on 26 steel wires are also carried out. Curves of stress relaxation and time are obtained and the stress relaxation model is established. It is found that stress relaxation will increase when any of the three factors(temperature, initial stress and time)increases. Temperature expansion experiment at high temperature on a steel wire is also carried out.
Keywords: prestressing steel wire; high temperature; creep; stress relaxation; temperature expansion
E-mail: zhengwenzhong@hit.edu.cn

钢骨超高强混凝土框架柱抗震性能的试验研究

贾金青¹ 姜 睿¹ 厚 童²
（1.大连理工大学海岸和近海工程国家重点室验室，辽宁大连116024；
2.中建国际(深圳)设计顾问有限公司，广东深圳518000）

摘要：通过试验，研究在较高轴压比条件下钢骨超高强混凝土柱的抗震性能。制作了13根剪跨比为2.75的钢骨超高强混凝土柱试件，其强度为94.9～105.4 MPa。设计时主要考虑轴压比、配箍率等因素对试件抗震性能的影响。在低周反复周期荷载作用下，试件的破坏形态是以弯曲破坏为主的弯剪破坏。根据采集的荷载、位移等数据，绘制出试件的滞回曲线和骨架曲线，并据此计算了试件的位移延性系数。试验表明，随着轴压比提高，试件的延性表现得越来越差；而较高配箍率可在一定程度上使延性得到改善。根据试验结果，提出了满足一定抗震位移延性要求的钢骨超高强混凝土柱轴压比限值和柱箍筋加密区最小配箍率的建议值，从而为工程设计提供参考。
关键词：钢骨超高强混凝土柱；轴压比；配箍率；抗震性能；延性

An experimental study on the seismic performance of steel reinforced
super high-strength concrete columns

Jia Jinqing¹ Jiang Rui¹ Hou Tong²
(1.State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, China；2. China State Construction International(Shenzhen)Design Consultant Co., Ltd., Shenzhen 518000, China)

Abstract: The seismic performance of steel reinforced super-high-strength concrete columns(SRSHC)is studied through a series of experiments. Thirteen specimens with concrete strength ranging 94.9～105.4MPa and a shear-span ratio of 2.75 were manufactured. The main experimental variables affecting the seismic performance of specimens were axial pressure ratio and stirrup reinforcement ratio. The columns subjected to low cyclic reversal lateral loads fail mainly in the flexural-shear mode failure. Shear force-displacement hysteretic curves and skeleton curves were drawn. Coefficient of the specimen displacement ductility was calculated. Experimental results indicate that ductility decreases with increase in axial pressure ratio, and increases with stirrup reinforcement ratio. Limit values of axial pressure ratio and minimum hoop reinforcement ratio of columns are proposed to satisfy definite ductility requirement. The suggested values provide a reference for engineering application and for the amendment of the current Chinese design code of steel reinforced concrete composite structures.
Keywords: steel reinforced super-high-strength concrete columns; axial pressure ratio; stirrup reinforcement ratio seismic performance; ductility
E-mail: keyknown@163.com

外包角钢与碳纤维布复合加固钢筋混凝土偏压柱承载力计算分析

卢亦焱^1,2 童光兵¹ 赵国藩² 张号军¹
(1.武汉大学，湖北武汉430072；2.大连理工大学，辽宁大连116023)

摘要：在14根外包钢与碳纤维布复合加固钢筋混凝土偏压柱试验研究的基础上，对这一新型复合加固柱的承载力进行理论分析，提出了采用条分法和简化法两种极限承载力的计算方法来计算复合加固偏压柱正截面承载力，其理论计算结果与试验结果对比，吻合较好。同时在此基础上分析了长细比、含角钢率、含碳纤维布率和偏心距等因素对复合加固偏压柱力学性能的影响。分析结果表明：含碳纤维布率和含角钢率越大，构件长细比越小，以及荷载的偏心距越小，复合加固效果越好。本文的研究成果为该新型复合加固技术在工程中应用提供了理论依据。
关键词：角钢；碳纤维布；复合加固；偏压柱；承载力计算

Analysis of the bearing capacity of RC eccentric compression columns
encased in angle steels and strengthened with CFRP

Lu Yiyan^1,2 Tong Guangbing¹ Zhao Guofan² Zhang Haojun¹
（1. Wuhan University, Wuhan 430072, China；2. Dalian University of Technology, Dalian 116024, China）

Abstract: Based on experimental studies of 14 RC eccentric compression columns strengthened with CFRP and encased in angle steels, theoretical analysis of the bearing capacity of the columns is conducted. Two types of methods (slice method and simple method)for bearing capacity calculation are presented, and the theoretical results conforms well with the experiment results. Also analyzed are the influences of CFRP ratio, angle steel ratio, slenderness ratio and eccentricity to the mechanical properties of the columns. The results indicate that decreases in slenderness ratio and eccentricity and increases in CFRP ratio and angle steel ratio are advantageous to the ultimate load-bearing capacity and the ductility.
Keywords: angle steel; carbon fiber reinforced plastic(CFRP); combination strengthening; eccentric compression column; calculation of bearing capacity
E-mail: yylu901@163.com

碳纤维布约束加固混凝土偏压柱的试验研究与分析

曹双寅 敬登虎 孙 宁
（东南大学，江苏南京210096）

摘要：通过5根碳纤维布约束加固混凝土柱的偏心受压试验，研究了加固后混凝土柱在不同偏心距荷载作用下的破坏特征和受力性能，对外包碳纤维布的横向应变、柱截面应变、侧向挠度以及极限承载能力等进行了分析。结果表明，碳纤维布约束加固小偏心受压混凝土柱是有明显效果的，随着偏心距的增大，加固效果逐渐减小；柱截面平均应变符合平截面假定；因偏心受压下混凝土受压膨胀不均匀碳纤维布存在拉应变梯度。根据拉应变梯度简化约束性能，提出修正的受压区等效矩形应力图形以及界限受压区相对高度值，并给出碳纤维布约束加固偏心受压柱的承载能力计算公式。
关键词：碳纤维布；偏压柱；应变梯度；等效矩形应力图形

Behaviors of concrete columns strengthened by CFRP sheets
under eccentric compression

Cao Shuangyin Jing Denghu Sun Ning
(Southeast University, Nanjing 210096, China)

Abstract: An experimental study of eccentrically loaded concrete columns confined by CFRP sheets is presented. The behaviors investigated in the test of five concrete columns reinforced by CFRP sheets include the ultimate strength, the lateral deflection, and the sectional strain distribution of concrete columns and transverse strains in the CFRP sheets. It is found that, via the reinforcement of CFRP sheets, the ultimate strength of concrete columns is enhanced and the ductility of concrete columns improved. The efficiency of reinforcement increases when the eccentricity decreases. It is also shown that the plane strain condition remains valid, i.e., strain in concrete is linearly proportional to the distance from the natural axis. The strain gradient in CFRP sheet, which is attributed to the non-uniform expansion of concrete, is observed. A formula is proposed for calculating the ultimate strength of eccentrically loaded concrete columns strengthened by CFRP sheets, including the modified equivalent rectangular stress block and the limit value of the relative depth of the compression zone.
Keywords: carbon fiber reinforced plastic(CFRP)sheet; eccentric compression column; strain gradient; equivalent stress zone
E-mail: cao@public1.ptt.js.cn

钢纤维混凝土替代构造配筋混凝土梁受弯性能试验研究

韩菊红 高丹盈 丁自强
（郑州大学，河南郑州450002）

摘要：为提高以裂缝为主要控制目标的大面积构造配筋混凝土受弯结构的抗裂性能，探讨钢纤维混凝土在此类结构中的应用，进行了16根三分点正向对称集中荷载作用下无筋足尺钢纤维混凝土梁替代构造配筋混凝土梁的弯曲抗裂性能试验，分析了钢纤维体积率、钢种和布筋位置等对试件受弯性能的影响。研究结果表明，钢纤维体积率0.5%的钢纤维混凝土梁的抗裂性能、限裂性能和承载力均优于截面中部配筋混凝土梁；钢纤维体积率(1.0～1.5)%的钢纤维混凝土梁的抗裂性能和限裂性能均明显优于截面双筋混凝土梁；钢纤维体积率(1.5～2.0)%的钢纤维混凝土梁除抗裂性能和限裂性能外，其承载力也优于截面双筋混凝土梁。因此，对于大型水利和土木工程中以抗裂或限裂为主要控制条件的受弯构件，可用钢纤维混凝土替代构造配筋混凝土。
关键词：钢纤维混凝土；构造配筋混凝土；抗裂；承载力

An experimental study on the flexural performances of SFRC beams
replacing composition RC beams

Han juhong Gao Danying Ding Ziqiang
( Zhengzhou University, Zhengzhou 450002, China)

Abstract: To improve the crack-resistance performance of massive flexural concrete structures usually with only composition reinforced steel bars, and to study the application of steel fibers to such structures, the flexural performances of 16 full size SFRC(steel fiber reinforced concrete)beams were tested under four concentrated forces. The influence of steel fiber volume content, steel type and its location on the flexural behavior was analyzed. The experimental results show that the crack-resistance performance and flexural capacity of SFRC beams with a 0.5% steel fiber volume content is superior to RC beams that are reinforced in the tension side of middle sections with the composition reinforcement, and the crack-resistance performance of SFRC beams with(1.0～1.5)% steel fiber volume content is obviously superior to composition RC beams, and the crack-resistance performance and flexural capacity of SFRC beams with(1.5～2.0)% steel fiber volume content are superior to RC beams reinforced on both the tension and the compression side with composition reinforcement. Therefore, the SFRC can replace the composition RC for improving crack-resistance performance of flexural structures.
Keywords: SFRC; composition RC beam; crack-resistance; flexural capacity
E-mail: hanjh99@zzu.edu.cn

粘钢加固RC梁承载性能的理论和试验研究

高轩能 周期源 陈明华
（华侨大学，福建泉州362021）

摘要：通过33根RC梁的试验，对不同粘钢位置、不同板件宽厚比和粘钢量加固的RC梁进行了全过程的理论与试验研究。基于对粘钢加固RC梁在荷载作用下的变形过程和破坏形式的观察，讨论了钢板宽厚比、粘钢位置和粘钢量对RC梁的短期刚度、挠度、开裂荷载、极限荷载和破坏形式等承载性能的影响。通过理论计算结果与试验结果的比较分析，得到了粘钢与RC梁之间的协调工作系数主要随截面相对受压区高度变化的结论，提出了粘钢加固RC梁协调工作系数、抗弯承载能力和挠度的计算公式，给出了工程设计建议和确定合适钢板宽厚比、粘钢位置和粘钢量的技术措施，为工程实际中粘钢加固RC梁的设计和承载能力的确定提供了依据。
关键词：粘钢加固RC梁；钢板宽厚比；粘钢位置；承载能力；协调工作系数；相对受压区高度

Theoretical and experimental research on bearing behavior of RC
beams strengthened by bonded steel plates

Gao Xuanneng Zhou Qiyuan Chen Minghua
(Huaqiao University, Quanzhou 362021, China)

Abstract: By conducting tests on 33 beams, RC beams strengthened at different positions with various quantities of bonded steel plates of various width-to-thickness ratios and areas are theoretically and experimentally studied. Based on the observation of the deformation process and destruction modes of those glued-steel RC beams under loading tests, the effects of width-to-thickness ratios, positions and areas of steel plates on the behavior of the beams, such as short period rigidity, bending deflection, cracking load, ultimate load and destruction modes, are discussed. Through comparing the theoretical results with the tests, it is found that the coordinate-working coefficient of glued-steel RC beam varies mainly with the relative depth of the compression zone. Formulations are proposed for calculating the coordinate-working coefficients, bending bearing capacity and deflections. Design suggestions and technical measures to decide the suitable width-to-thickness ratios, positions and areas of glued-steel RC beams are also presented.
Keywords: RC beam strengthened by bonded steel plates; width-to-thickness ratio of steel plate; glued-steel position; bearing capacity; coordinate-working coefficient; relative depth of compression zone
E-mail: gaoxn@hqu.edu.cn

构造柱约束的混凝土小砌块墙体抗震性能的试验研究

周锡元^1,2 李万举¹ 闫维明¹ 郭米娜¹ 周宏宇¹
（1.北京工业大学工程抗震与结构诊治北京市重点实验室，北京100022；
2.中国建筑科学研究院工程抗震研究所，北京100013）

摘要：通过对4片不同构造形式的混凝土小砌块足尺墙片在低周反复荷载作用下的恢复力试验，观测墙体在荷载作用下开裂和破坏的发展过程，研究了不同构造措施和不同结构类型的墙体的破坏形态、钢筋应变及墙体变形能力，得到墙体的开裂荷载和极限荷载。试验表明：墙体的开裂位移非常小，即使墙体能承受较大的水平荷载也很容易开裂；构造柱约束小砌块墙体能有效地提高墙体的承载力和抗震性能，增强变形能力，防止开洞墙体的脆性破坏；加水平钢丝网片和配筋带可以进一步提高墙体的延性。试验还表明墙体在开洞后极限承载力下降较多，需要有相应的加强措施，以提高其延性和抗震能力。
关键词：混凝土小砌块；低周反复荷载；抗震性能；构造柱

An experimental study on the seismic behavior of small concrete block
walls confined by tie columns and beams

Zhou Xiyuan^1,2 Li Wanju¹ Yan Weiming¹ Guo Mina¹ Zhou Hongyu¹
（1.Beijing Laboratory of Earthquake Engineering and Structural Retrofit, Beijing University of Technology, Beijing 100022，China; 2.Institute of Earthquake Engineering,China Academy of Building Research,Beijing100013, China）

Abstract: In order to study the failure mode, seismic behavior and deformation capacity, four full-size small concrete block walls with different structural details are tested under low cyclic loadings. Based on the laboratory experiment, the cracking and damage process of the walls are studied and the initial cracking load and the ultimate load for the walls are determined. The strain of the reinforcing bars are recorded and analyzed. The test results indicate that the walls are easy to crack even if they can take rather large horizontal loads. Tie steel fabric sheets and columns can improve the seismic behavior, and enhance deformation capacity to prevent brittle failure of walls with openings on them. The ultimate loads of the walls are reduced because of the door holes, and strengthening measures should be taken in order to improve the ductility and earthquake resistance capacity.
Keywords: small concrete block; low cyclic loading; seismic behavior; tie column
E-mail: liwanju@emails.bjut.edu.cn

构造柱约束的混凝土小砌块墙体抗震性能的试验研究

周锡元^1,2 李万举¹ 闫维明¹ 郭米娜¹ 周宏宇¹
（1.北京工业大学工程抗震与结构诊治北京市重点实验室，北京100022；
2.中国建筑科学研究院工程抗震研究所，北京100013）

摘要：通过对4片不同构造形式的混凝土小砌块足尺墙片在低周反复荷载作用下的恢复力试验，观测墙体在荷载作用下开裂和破坏的发展过程，研究了不同构造措施和不同结构类型的墙体的破坏形态、钢筋应变及墙体变形能力，得到墙体的开裂荷载和极限荷载。试验表明：墙体的开裂位移非常小，即使墙体能承受较大的水平荷载也很容易开裂；构造柱约束小砌块墙体能有效地提高墙体的承载力和抗震性能，增强变形能力，防止开洞墙体的脆性破坏；加水平钢丝网片和配筋带可以进一步提高墙体的延性。试验还表明墙体在开洞后极限承载力下降较多，需要有相应的加强措施，以提高其延性和抗震能力。
关键词：混凝土小砌块；低周反复荷载；抗震性能；构造柱

An experimental study on the seismic behavior of small concrete block
walls confined by tie columns and beams

Zhou Xiyuan^1,2 Li Wanju¹ Yan Weiming¹ Guo Mina¹ Zhou Hongyu¹
（1.Beijing Laboratory of Earthquake Engineering and Structural Retrofit, Beijing University of Technology, Beijing 100022，China; 2.Institute of Earthquake Engineering,China Academy of Building Research,Beijing100013, China）

Abstract: In order to study the failure mode, seismic behavior and deformation capacity, four full-size small concrete block walls with different structural details are tested under low cyclic loadings. Based on the laboratory experiment, the cracking and damage process of the walls are studied and the initial cracking load and the ultimate load for the walls are determined. The strain of the reinforcing bars are recorded and analyzed. The test results indicate that the walls are easy to crack even if they can take rather large horizontal loads. Tie steel fabric sheets and columns can improve the seismic behavior, and enhance deformation capacity to prevent brittle failure of walls with openings on them. The ultimate loads of the walls are reduced because of the door holes, and strengthening measures should be taken in order to improve the ductility and earthquake resistance capacity.
Keywords: small concrete block; low cyclic loading; seismic behavior; tie column
E-mail: liwanju@emails.bjut.edu.cn

多层住宅新型复合结构的抗震试验研究

王新玲 赵更歧 张海东
（郑州大学，河南郑州450002）

摘要：针对用于代替黏土砖住宅结构的钢筋混凝土柔性梁柱加人字支撑形成的新型复合结构，进行了低周反复荷载下的抗震试验研究。试验采用1∶2的缩尺模型；根据计算的各抗震设防烈度对应的地震作用及开裂荷载、屈服荷载设计出加载制度；采用液压伺服装置进行低周反复荷载试验。根据试验现象和数据，分析了复合结构裂缝及塑性铰出现的顺序和位置；绘出试件的滞回曲线、骨架曲线；计算出结构的延性系数。在此基础上，研究复合结构恢复力模型和表达式，分析其耗能机制和抗震能力，结果表明复合结构具有“强柱、中梁、弱支撑”多道抗震防线的抗震性能。采用建筑工程软件PKPM计算的开裂及屈服荷载和试验值符合较好。
关键词：复合结构；低周反复荷载；试验研究；抗震性能

An experimental study on the earthquake resistance of novel multistory composite structures
Wang Xinling Zhao Gengqi Zhang Haidong

(Zhengzhou University, Zhengzhou 450002, China)

Abstract: Experiments are conducted on novel composite structures with flexible reinforced concrete beams and columns and herringbone braces under low-period cyclic load. A test model of scale 1∶2 is manufactured. The loading process is designed on the basis of the cracking and yielding loads and earthquake action as calculated for seismic load of fortification intensity. According to the experimental results, the sequence and position of cracks and plastic hinges of the compound structure are analyzed, and the hysteresis curves, skeleton curves and the coefficient of ductility obtained. A computation model of rehabilitation force is proposed. The results indicate that the collapsing mechanism of the composite structure is formed by plastic hinges occurring in the order in braces, beams and columns. The results show that the composite structure possesses good seismic property due to multiple lines of defense. The calculation of the cracking load and the failure load with the building engineering software, PKPM, is in good agreement with test results.
Keywords: composite structure; low-period cyclic load; experimental study; seismic property
E-mail: xinlingwang@zzu.edu.cn

工字梁的抗剪极限承载力

童根树 任 涛
（浙江大学，浙江杭州310027）

摘要：对工字梁腹板抗剪极限承载力的研究进行总结，对各种公式与文献中的试验结果进行对比，将拉力场理论和转向应力场理论的假定与ANSYS分析揭示的腹板应力发展变化规律进行对比，指出了假定和数值分析结果的不一致。提出了翼缘对腹板转动约束的合理参数，得到精度良好的考虑翼缘约束的腹板剪切屈曲系数。利用得到的屈曲系数，考虑翼缘抗弯承载力的贡献，提出新的工字梁抗剪极限承载力的计算公式。与现有试验数据和ANSYS非线性有限元分析结果的对比，证实建议方法离散性较小，适用范围广，尤其是对于通用高厚比较大的梁，较以往方法有了较大改进。
关键词：剪切屈曲；极限承载力；腹板；工字梁

Shear resistance of slender webs in I-girders
Tong Genshu Ren Tao

(Zhejiang University, Hangzhou 310027,China)

Abstract: This paper presents a brief review on the current methods for design of webs in I-girders under shear. Various formulae are compared with available test results. The assumptions used in the tension field theory and the rotated stress theory were compared with the phenomena revealed in a nonlinear analysis by using ANSYS，and the discrepancies between the theories and the numerical analysis were demonstrated. A rational parameter is proposed to describe the restraint provided to the web by the flanges, and so is a formula for the shear buckling coefficient incorporating this restraint with excellent accuracy. The proposed formula is then employed to construct a new formula to predict the ultimate strength of thin webs in shear, including the contribution from the flange. Good correlation is found between the proposed formula and tests. The proposed method may be employed for both stiffened webs and non-stiffened webs. For webs with larger universal slenderness, the proposed method demonstrates a great improvement when compared with current methods.
Keywords: shear buckling; ultimate strength; web; I-girder
E-mail: tonggs@zju.edu.cn

GFRP复合材料加固带壁柱砖墙抗震性能试验研究

王全凤 柴振岭 黄奕辉 杨勇新 曾志兴
（华侨大学，福建泉州362021）

摘要：对玻璃纤维复合材料（Glass Fiber Reinforced Polymer, GFRP）加固带壁柱砖墙抗震性能进行试验研究。通过1片未加固带壁柱砖墙和8片 GFRP 加固带壁柱砖墙在低周往复荷载作用下的抗震性能试验，阐述了各试件的破坏特征；研究GFRP加固前后墙体的滞回特性、刚度及退化特性、变形性能、耗能性能等变化规律，以及加固方式、加固量和“对拉”锚固措施对加固效果的影响。研究结果表明：加固方式对墙体的刚度退化性能和变形性能影响不大，但对墙体的耗能性能影响较明显；按照本文提出的加固方式粘贴GFRP能够有效地提高墙体的极限荷载、减缓墙体的刚度退化、增强其变形能力和耗能能力；同时考虑采用混合加固方式、增大加固量、采用锚固措施三因素时，墙体的抗震性能较好。
关键词：玻璃纤维复合材料（GFRP）；加固；带壁柱砖墙；“对拉”锚；抗震性能

An experimental study on the seismic performance of brick masonry
walls with pilaster reinforced by GFRP

Wang Quanfeng Chai Zhenling Huang Yihui Yang Yongxin Zeng Zhixing
(Huaqiao University, Quanzhou 362021, China)

Abstract: An experimental research is conducted on the seismic performance of brick masonry walls with pilaster reinforced by glass fiber reinforced polymer(GFRP). Based on the low cyclic loading experiments on one brick masonry wall with ordinary pilaster and eight specimens of masonry walls with pilaster strengthened by GFRP, the failure characteristics of the walls are explained; seismic performance characteristics, such as resilience, rigidity and its degeneration, deformation, and energy dissipation are studied; and influence of the measures including strengthening means, reinforcement area proportion between GFRP and wall surface,“through-wall”anchorage on reinforcement effects are studied. The test results indicate that the strengthening mode has little influence on wall deformation, wall rigidity and its degeneration, whereas it has obvious influence on the energy dissipation capacity of the wall. The ultimate capacity, deformation and energy dissipation of the walls reinforced by glass fiber sheets are remarkably higher. Wall with CFRP reinforced pilaster will show a better seismic performance when coupled with other various strengthening means, higher reinforcement proportion and“through-wall”anchorage.
Keywords: glass fiber reinforced polymer(GFRP); reinforcement; brick masonry wall with pilaster;“through-wall”anchorage; seismic performance
E-mail: qfwang@hqu.edu.cn

马钢耐火钢高温下材料性能试验研究

蒋首超¹　陆立新¹　李国强¹　沈俊昶²　吴保桥³　吴结才³
（1. 同济大学，上海　200092；2. 钢铁研究总院，北京100081；
3. 马鞍山钢铁股份有限公司技术中心，安徽马鞍山243003）

摘要：为了得到高温下耐火钢的材料特性，对马钢集团开发的耐火钢在高温下的力学性能进行了试验研究。通过高温下的恒温加载拉伸试验，得到不同温度下耐火钢的屈服强度、极限强度、延伸率、面缩率和应力-应变关系，并测定高温下耐火钢的热膨胀系数，采用悬丝耦合共振法测定高温下耐火钢的初始弹性模量。试验表明，马钢耐火钢在600℃时的屈服强度大于常温下的2/3，弹性模量大于常温下的3/4。通过对试验结果的分析，拟合得到耐火钢的各力学指标参数随温度变化的计算公式，这些公式可用于耐火钢结构抗火性能的分析与设计。
关键词：高温；试验；力学性能；耐火钢

An experimental study on high-temperature properties of
fire-resistant steel made by Masteel

Jiang Shouchao¹ Lu Lixin¹ Li Guoqiang¹ Shen Junchang² Wu Baoqiao³ Wu Jiecai³
（1. Tongji University, shanghai 200092, China; 2. Central Iron & Steel Research Institute, Beijing 100081, China; 3. Maanshan Iron & Steel Co., Ltd., Maanshan 243003, China)

Abstract: Experiments are carried out to determine the high-temperature mechanical properties, such as yield strength, tensile strength, elongation, Poisson ratio and stress-strain relationship, of fire-resistant steel made by the Maanshan Iron & Steel Co. Ltd.. A coupled vibration method on suspended free poles is employed to determine the initial Young's modulus at elevated temperatures, also the thermal expansion coefficients of fire-resistant steel. Test results indicate that the yield strength of fire-resistant steel at 600℃ is higher than the yield strength at ambient temperature by two thirds, and the initial Young's Modulus at 600℃ is higher than of that at ambient temperature by three quarters. In conclusion, the functions of coefficients for mechanical properties of fire-resistant steel under variable temperatures are developed by using a regression analysis.
Keywords: high-temperature; experiment; mechanical property; fire-resistant steel
E-mail: scjiang@mail.tongji.edu.cn

混凝土中碱-硅反应的膨胀机理研究

尹 芪
（华南理工大学，广东广州510640）

摘要：利用高碱活性的蛋白石和低碱活性的天然水晶研究碱—硅反应的膨胀力来源。试样粉磨至40~80 μm后与0.7 mol/L 的NaOH溶液混合，至反应达平衡，反应产物用真空干燥。取约1 g产物，压制成直径14 mm ,厚约3~4 mm的薄片后，采用自行设计的FLM1-凝胶膨胀自动测量仪分别在无半渗膜和有半渗膜条件下测量其吸水膨胀量。在无半渗膜条件下，反应产物的吸水膨胀量都很小；在有半渗膜条件下，反应产物吸水后都表现出明显的膨胀现象，其中蛋白石反应产物的膨胀量达85.5％，水晶的膨胀量有5.1％，这与反应溶液的pH值降低趋势相对应，也与样品本身的碱活性大小一致。结果表明，产物吸水肿胀所引起的膨胀量是很有限的，渗透压是碱-硅酸反应的主要膨胀来源，从而为碱-硅反应的渗透压假说提供试验论据。
关键词：碱-硅反应；蛋白石; 渗透压；膨胀

An experimental study on the expansion mechanism of
alkali-silica reaction in concrete

Yin Qi
（South China University of Technology, Guangzhou 510640, China）

Abstract: Opal, a high alkali active mineral, and crystal, a low alkali active mineral, are employed to experimentally study the source of expansion force of alkali-silica reaction (ASR). Samples were ground to granules of diameters of 40~80μm and mixed with a NaOH solution of 0.7 mol/L, respectively. When the reaction reached equilibrium, the products were dried in vacuum. Then, about 1g of each of the dried products was pressed into a slice of a diameter of 14mm and a thickness of 3mm to 4mm. The slices were moved to a FLM1-Gel automated measuring device designed by the writer to test the expansion properties of the specimens after imbibing water. Without semi-permeation membrane, the expansion of each slice was small. With semi-permeation membrane, the expansion of each slice was obvious. The expansion of opal slice amounts to 85.5％ and crystal slice 5.1%, which is consistent with the decreasing trend of the pH value of each mixture solution and the alkali active level of the sample. The results indicate that the expansion caused by osmotic pressure was remarkable, whereas the expansion caused by swelling pressure was small. These results provide an experimental evidence of the osmotic pressure hypothesis of ASR.
Keywords: alkali-silica reaction; opal; osmotic pressure; expansion
E-mail: yinqi@scut.edu.cn

二次预应力梁的徐变和承载力试验研究

邵旭东¹ 张 伟² 彭 聪¹ 邓 军¹ 马 竞³
（1湖南大学，湖南长沙410082；2重庆交通科研设计院，重庆400067；
3. 广东清远公路管理局，广东清远511515）

摘要：在中小跨径的预应力梁式桥中，经常出现张拉过程中直梁反拱过大，弯梁横移，刚构桥立柱开裂等问题，这些都是由于预应力附加内力过大引起的。为了解决此类问题，提出二次预应力新型桥梁结构的概念。通过对这种结构与常规预应力结构的比较分析和10 m跨径的二次预应力梁和常规预应力梁的对比试验，证明二次预应力技术在低高度梁中的应用，可以大大改善低高度梁在施工和长期使用过程中的受力和变形性能。同时推导了二次预应力结构任意时刻的徐变内力计算公式，并验证了二次预应力结构的承载能力。指出二次预应力技术在中小跨径预应力梁式桥中有着广阔的应用前景。
关键词：二次预应力；徐变；组合结构；试验研究；承载能力

An experimental study on the creep behavior and bearing capacity of
twice prestressed concrete beams

Shao Xudong¹ Zhang Wei² Peng Cong¹ Deng Jun¹ Ma Jing³
(1. Hunan University, Changsha 410082,China；2. Chongqing Communications Research and Design Institute，Chongqing 400067,China；3. Guangdong Qingyuan Highway Administration, Qingyuan511515, China)

Abstract: Due to the large additional stress from prestressing, many serious problems, such as the camber of a straight bridge beam being too large, curved beam drifting in its transverse direction, and columns of rigid beam bridge cracking frequently, may occur in the pre-stress tensioning process of medium or short span prestressed beam bridges. To deal with these problems, a new type of twice prestressed beam is herein proposed. Through theoretical and experimental comparisons between this new structure and the traditional prestressed concrete structure, it is found that the application of twice prestressing can significantly improve the mechanical performance of the beam in the construction process and long-term use. A theoretical solution is derived for the creep strain and internal force due to twice prestressing, and the bearing capacity of the structure is validated.
Keywords: twice prestressing; creep; composite structure; experimental research; bearing capacity
E-mail: shaoxd@hnu.cn

钢桥面铺装局部修复方案试验研究

黄 卫 钱振东 张 磊
（东南大学，江苏南京210096）

摘要：钢桥面铺装的修复技术是钢桥面铺装技术研究的重要组成部分，其复杂性在一定意义上远大于新建大跨径钢箱梁桥的桥面铺装研究。江阴大桥为主跨1385m的钢箱梁悬索桥，钢桥面采用47 mm浇注式沥青混凝土铺装，通车三年多后钢桥面出现大面积破坏。对江阴大桥钢桥面铺装出现的破坏类型以及钢箱梁构造等特点进行研究，在室内试验研究如弯曲试验、拉拔试验、车辙试验、复合梁疲劳试验的基础上，提出了5.0 cm、5.5 cm、6.0 cm不同厚度的双层环氧沥青混合料与“浇注式沥青混合料+环氧沥青混合料”4种结构方案，并利用江阴大桥钢桥面铺装大修的机会，选取代表性梁段作了试验段。研究表明双层环氧沥青混合料性能优于其他方案，此研究为我国钢桥面铺装局部修复方案的确定以及成功实施提供基础依据。
关键词：局部修复；环氧沥青混合料；浇注式沥青混合料；江阴大桥

An experimental study on partly patching scheme of steel bridge deck paving
Huang Wei Qian Zhendong Zhang Lei

(Southeast University, Nanjing 210096 China)

Abstract: Patching techniques are an important part of steel bridge deck paving. In some sense, the complexity of patching is much greater than paving. We have investigated certain patching techniques applied to the Jiangyin Bridge in China. The Jiangyin Bridge over The Yangtze River is a box-girder suspension bridge with its main span being 1385m and a cast asphalt concrete paving with a thickness of 47mm. After three years of traffic, considerable structural damages on the driveway paving were discovered, such as rutting, transversal shattering, cracking and so on. After an analysis of the structural damages of the pavement and structural characteristics of the box-girder of the bridge together with laboratory tests, such as bending test, pull-out test, rutting test and fatigue test of complex beams, four partly patching schemes of banal-layer epoxy asphalt and“cast asphalt + epoxy asphalt”with thicknesses of 5.0cm, 5.5cm, 6.0cm, respectively, have been tried and evaluated. A representative section of the Jiangyin Bridge is selected for the test, as the steel deck paving is being repaired. The study indicates that the banal-layer epoxy asphalt concrete is superior than other schemes.
Keywords: partial patching; epoxy asphalt mixture; cast asphalt mixture; Jiangyin Bridge
E-mail: qianzd@seu.edu.cn

多梁式混凝土桥梁结构刚度的裂缝特征——动力分解综合识别法

贺拴海¹ 徐 兴²
（1.长安大学，陕西西安710064；2. 浙江大学，浙江杭州310027）

摘要：基于有限模型梁的静、动力交替试验研究，分析了钢筋混凝土梁的基频、静刚度、动刚度在“正常使用”阶段的变化规律，建立静、动刚度比与结构内力、自振基频的回归关系式，在对混凝土梁进行非线性分析的基础上，建立了结构裂缝统计参数与结构特征参数之间的回归关系。基于模型桥的静、动力交替试验研究，分析了多梁式T型结构在“正常使用”阶段的变形、应力、内力、频率的变化规律和裂缝开展过程及其统计参数。提出易被工程技术人员所接受的多梁式结构预测评估的动力分解法——根据外观裂缝检查成果和动力试验参数将桥跨结构分解为单片梁，获得各梁目前状态下的动刚度及静刚度，并得到模型试验成果的验证。
关键词：钢筋混凝土梁式桥；裂缝；刚度；基频；动力分解法

Dynamic decomposition-combination method for identification of crack
features of T-type beam concrete bridge

He Shuanhai¹ Xu Xing²
（1.Chang'an University，Xi'an 710064,China；2. Zhejiang University，Hangzhou 310027,China）

Abstract: The static and dynamic behaviors of reinforced concrete T-type beams are studied by both theoretical and experimental means. Using nonlinear finite element analysis results, we have established the relationships between the ratio of static stiffness to dynamic stiffness of a beam and the applied bending moment, the ratio and resonance frequency, crack characteristic factor and sectional characteristic factor based on the variations of the resonance frequency, and the changes in static and dynamic stiffness during the cracking stage of the beam. The static and dynamic behaviors of a reinforced concrete model bridge with five T-type beams are also studied. The variations of the stress-strain, internal force, resonance frequency, cracking process and crack characteristic factor are analyzed comprehensively. In the decomposition-combination method, as verified by model tests, the bridge is divided into single T-type beams by using the ratio of dynamic stiffness of individual beams as evaluated by the crack characteristic factor and the resonance frequency. From the vibration tests, the actual stiffness of each beam of the bridge is obtained.
Keywords: reinforced concrete beam bridge; crack; stiffness; resonance frequency; dynamic decomposition-combination method
E-mail: keji_1@chd.edu.cn

地基上混凝土梁的温度应力

朱伯芳
（中国水利水电科学研究院，北京100038）

摘要：地基上混凝土梁常需控制温度应力以避免裂缝。本文首先简要介绍马斯洛夫应力解，然后用弹性力学方法给出地基对梁的温度变形的抗力系数，从而得到地基上梁的温度应力的一套完整解法。根据地基弹性模量及梁的长高比，对梁所受到的地基约束作用分为4类：（a）弯曲变形完全约束，水平变形部分约束；（b）弯曲变形完全约束，水平变形无约束；（c）弯曲变形部分约束，水平变形无约束；（d）水平变形和弯曲变形均无约束。对于每类约束情况分别给出了简洁的温度应力计算公式，使计算得到简化。给出了混凝土弹性模量和温度随龄期而变化时的计算方法。指出了目前工程界采用的地基上梁温度应力计算方法的不足之处。
关键词：地基梁；抗力系数；温度应力；计算方法

Thermal stresses in concrete beams on elastic foundations

Zhu Bofang
（China Institute of Water Resources and Hydropower Research, Beijing 100038, China）

Abstract: It is necessary to control thermal stresses and prevent cracks in concrete beams on elastic foundations. The solutions proposed by Maslof for thermal stresses in beams on Winkler foundation have not found applications in engineering, because there are no formulas for the coefficients of foundation restraint involved in the solutions. In this paper, formulas for coefficient of foundation restraint are obtained by using the theory of elasticity. The thermal stresses are categorized into four types by referring to the relative stiffness of beam and foundation:(a)full restraint on bending and partial restraint on horizontal displacement;(b)full restraint on bending and no restraint on horizontal displacement; (c)partial restraint on bending and no restraint on horizontal displacement; (d)no restraint on both bending and horizontal displacement. Practical, simple yet accurate formulas are provided for each type of beams.
Keywords: beam; foundation; thermal stress; calculation method
E-mail：bfzhu@iwhr.com

桥头软基现浇筒桩处理现场试验分析

朱明双　朱向荣　王金昌
（浙江大学，浙江杭州310027）

摘要：为研究现浇筒桩和土工格栅加筋碎石垫层组成的复合地基加固软弱路基的作用机理及效果，介绍了某高速公路桥头筒桩处理中进行的地表沉降、分层沉降、深层土体位移、孔隙水压力、桩土应力等项目的现场测试成果。结果发现：该处理方法具有经济合理，承载力高，沉降小等特点，为解决软土“桥头跳车”提供了一种经济、有效的手段；土工格栅可以很好地调节荷载分布，使荷载更多的向桩身集中；超静孔压不大，且有规律性，不影响沉降稳定性；地基侧向变形小，变形速率在时间和深度上都呈递减趋势。
关键词：筒桩；复合地基；桩顶盖板；土工格栅；现场试验

Analysis of cast-in-situ tubular piles in soft foundation improvement at bridge approaches

Zhu Mingshuang Zhu Xiangrong Wang Jinchang
(Zhejiang University，Hangzhou 310027，China)

Abstract: To study the performance and feasibility of tubular piles with geogrid reinforced macadam cushion, field test results, including settlement, lateral movement, pore water pressure, and pile-soil stress, are presented. The study indicates that the piles may improve the bearing capacity and meet engineering requirement on settlement with low cost, providing an economical and effective solution to the difficult problem of“bump at bridge-head”with soft foundations. The geogrid can adjust the load distribution, thus causing the pile to carry more load and the foundation becoming more stable. Since the excess pore pressure is small, it has no influence on the stability of the foundation. Besides, the horizontal ground displacement is also small, thus the deformation rate decreases with time and depth.
Keywords: tubular pile; composite ground; pile cap decking; geogrid; in-situ test
E-mail: jianhua1109@sina.com.cn

箱形基础在上下部共同作用下整体受力的极限分析

严 平 包红泽 龚晓南
（浙江大学，浙江杭州 310027）

摘要：提出箱形基础在上下部共同作用下整体受力极限分析方法，并与实际工程实测结果对照验证其合理性与可靠性。将上部结构与箱基、地基视为整体，借助于上下部同步进入极限状态的虚功率方程，从极限分析的角度对箱基在上下部共同作用下的整体受力进行求解。根据十字机动破坏模型和双抛物线基反力破坏模式，求出相应箱基整体受力上限解。箱基整体进入极限受弯状态时，视上部结构为框架体系，计算上部结构抗弯刚度对箱基整体受力解约束效应分析。选取两个具有较完整实测结果的箱形基础工程按以上方法进行极限分析，并与实测对比。结果显示，与现行“箱筏基规范”考虑上部效应法相比，该极限分析方法计算结果更接近实测。同时，上下部共同作用整体受力极限分析方法更易于手算和电算编程，并可用于各种基反力模式。
关键词：箱形基础；上下部作用；极限分析

Limit analysis of box foundation and its interaction with superstructure

Yan Ping Bao Hongze Gong Xiaonan
(Zhejiang University, Hangzhou 310027, China)

Abstract: By integrally considering the interaction effects of superstructure and foundation, a limit analysis of box foundation is conducted, using the principle of virtual work together with a cruciform flexible damage model and a dual parabola foundation pressure model. From the analysis, a set of design formulas are proposed. In order to verify the validity of the proposed formulas, limit analysis of two realistic box foundations is carried out. Comparing with the actual measurements, the proposed formulas are proved to be rational and reliable. The limit analysis of the box foundation involves an simple calculations, and can be employed with several damage models.
Keywords: box foundation; interaction between superstructure and foundation; limit analysis
E-mail: yanpin@vip.sina.com.cn

黄土高路堤沉降变形预测模型研究

景宏君^1,2 俞茂宏¹
(1. 西安交通大学，陕西西安710049；2. 陕西省咸阳市交通局，陕西咸阳712000)

摘要：以兰州—海石湾高速公路高69 m黄土路堤沉降资料为研究样本，采用经修正了非匀速填土和非等步长沉降观测时间的GM（1，1）灰色理论预测模型进行黄土高路堤工后最终沉降量预测，与等比级数曲线模型预测结果对比，认为这两种预测模型都能很好地预测黄土高路堤工后最终沉降量，且灰色预测模型能较等比级数曲线预测模型更好地反映黄土高路堤不均匀沉降趋势。同时认为，考虑了沉降观测时间非等步长性和路堤填土速度不均匀性的灰色预测模型其预测结果更符合黄土高路堤沉降变形趋势，可进行进一步的研究、推广和应用。
关键词：道路工程；黄土高路堤；沉降；预测模型

Model study for prediction of settlement of loess-fill high embankments

Jing Hongjun^1,2 Yu Maohong¹
(1. Xi'an Jiaotong University, Xi'an 710049, China;
2. Xianyang Municipal Communications Bureau of Shaanxi Province, Xianyang 712000,China)

Abstract: Using the settlement data of a 69m loess-fill high embankment of an expressway as the sample, a GM (1,1)grey model, which has been modified to consider non-homogeneous filling rate and non-equal time step of prediction, is employed to predict the final embankment settlement. A comparitive study is conducted on the predicted results of the current model against those of a growth curve model. It shows that while both models can predict the final settlement of high fill embankments, the grey model gives better prediction on the non-homogeneous deformation of high fill embankments.
Keywords: road engineering; loess-fill high embankment; settlement; prediction model
E-mail: jinghj@public.xa.sn.cn

刚性路面在运动车辆作用下的动力响应

周华飞 蒋建群
(浙江大学，浙江杭州310027)

摘要：针对运动车辆引起的路面结构动力问题，采用移动荷载作用下Kelvin地基上无限大Kirchhoff薄板为力学分析模型，分析了运动车辆作用下刚性路面的动力响应。首先采用积分变换法推导了板挠度的Green函数，并通过Duhamel积分求得各种移动荷载模式作用下板稳态挠度的二维积分解析解，包括恒常和简谐移动点源、线源和面源荷载。然后采用自适应数值积分算法计算解析解中的二维无穷积分，得到了板稳态挠度的数值结果。最后对速度和阻尼等对板稳态挠度的最大值和空间分布的影响进行分析，得到了荷载临界速度，发现了板动力响应的特性和规律。
关键词：稳态响应；Green函数；自适应数值积分算法；移动荷载；Kelvin地基；无限大板

Dynamic response of rigid pavements to moving vehicles

Zhou Huafei Jiang Jianqun
(Zhejiang University, Hangzhou 310027, China)

Abstract: To investigate the dynamic response to moving vehicles, a rigid pavement is modeled as an infinite plate on Kelvin foundation subjected to moving loads. A Green's function is derived by using the integral transform method. Analytical solutions of steady-state displacements are developed by using Duhamel's integral for constant or harmonic point, line and area loads. An adaptive quadratic algorithm is employed to calculate the double infinite integrals in the analytical solution. Numerical results for steady-state displacements induced by a constant moving point load are presented as illustrations. The effects of velocity and damping on the maximum and distribution of displacement are analyzed, and the critical velocity and the characteristics of dynamic responses of the plate were found.
Keywords: steady-state response; Green's function; adaptive quadrature algorithm; moving load; Kelvin foundation; infinite plate
E-mail: mailtofly@163.com