Post-fire cyclic behavior of reinforced concrete shear walls

The effects of fire exposure,reinforcement ratio and the presence of axial load under fire on the seismic behavior of reinforced concrete(RC) shear walls were investigated.Five RC shear walls were tested under low cyclic loading.Prior to the cyclic test,three specimens were exposed to fire and two of them were also subjected to a constant axial load.Test results indicate that the ultimate load of the specimen with lower reinforcement ratio is reduced by 15.8%after exposure to elevated temperatures.While the reductions in the energy dissipation and initial stiffness are 59.2%and 51.8%,respectively,which are much higher than those in the ultimate load.However,this deterioration can be slowed down by properly increasing reinforcement due to the strength and stiffness recovery of steel bars after cooling.In addition,the combined action of elevated temperatures and axial load results in more energy dissipation than the action of fire exposure alone.

条件价值法评估旅游资源非使用价值的可靠性检验

CVM的有效性和可靠性检验在CVM研究中占据愈来愈重要的地位,国内目前该方向的研究还是空白。本文结合武夷山景区非使用价值CVM案例研究,对CVM可靠性作一些探索。案例CVM的研究结果表明:武夷山景区旅游资源非使用价值32.42×108元/a(2006年价格),人均保护支付意愿16.42元/(人.a)。以全国环评工程师为目标人群,相隔半年进行了可靠性检验。PC1、PC2样本数及地域分布基本一致,可靠性检验结果表明:①样本的性别、年龄、经济收入、对旅游的热爱程度、对武夷山景区的偏爱程度及对武夷山的熟悉程度等社会经济特征与相对应的是否具有支付意愿(正WTP率)的相关性分析比照具有较好的重现性。在中国环评工程师这一特殊的目标人群中,男性、到过武夷山景区特别是近期有计划去武夷山者、对武夷山较为熟悉者对于武夷山景区非使用价值通常具有较明显的支付意愿。②样本社会经济特征对支付意愿额度的影响相关性的重现性较好,在环评工程师中具有正支付意愿这-特定目标人群中,其支付额度具有较大的随机性,与被调查者的性别、年龄、对旅游的热爱程度、对武夷山的偏爱程度及熟悉程度均不存在显著性相关,但与收入水平呈弱相关。③WTP中位数与平均数重现性良好。PC1、PC2的中位数相差1.58元(RMB),误差很小。通过本次可靠性检验,武夷山景区旅游资源非使用价值CVM调查结果可靠性得到了保证。

Relationship between repeated triaxial test and Hamburg wheel tracking test on asphalt mixtures

Both the repeated triaxial test （RTT） and the Hamburg wheel tracking test （HWTT） are adopted to evaluate the high temperature performance of the stone mastic asphalt （SMA） and the mastic asphalt （MA）. The correlation of the permanent deformations of the MA and the correlation of the deformation developments of the SMA between the two tests are analyzed, respectively. Results show that both the two tests can effectively identify the high temperature performance of mixtures, and the correlation between the final results of the two tests as well as that between the deformation developments of the two tests are excellent with R20.9. In order to further prove the correlation, viscoelastic parameters estimated from the RTT results is used to simulate the rutting development in the HWTT slabs by the finite element method （FEM）. Results indicate that the correlation between the two tests is significant with errors less than 10%. It is suitable to predict the rutting development with the viscoelastic parameters obtained from the RTT.

Screening of Chinese Herbal Medicines Resistant to Chicken Escherichia coli and Infectious Laryngotracheitis Virus

[Objective] This study aimed to screen Chinese herbal medicines resistant to Chicken Escherichia coli and infectious laryngotracheitis virus. [Methed] Conven- tional punch method, test tube method and plate dilution method were adopted for in vitro susceptibility test of chicken E, coil strains O5 and O8 using 13 kinds of Chi- nese herbal medicines including Sanguisorba officinalis, Coptis chinensis, Anemar- rhena asphodeloides, Strobilanthes cusia, Agastache rugosa, etc.; chicken embryo inoculation experiment was adopted to screen Chinese herbal medicines resistant to chicken infectious laryngotracheitis virus. [Result] Sanguisorba officinalis, Fructus mume, Rheum officinale, Coptis chinensis, Herba Taraxaci, Anemarrhena asphode- Ioides, Scutellaria baicalensis and Rhizoma Fagopyri Cymosi had ideal antibacterial effect against chicken E. coil strain O5; Sanguisorba officinalis, Fructus mume, Rheum officinale, Coptis chinensis, Herba taraxaci and Rhizoma Fagopyri Cymosi had ideal antibacterial effect against chicken E. coil strain 08; other Chinese herbal medicines showed relatively poor or no antibacterial effect. Results of chicken embryo inoculation experiment showed that nine kinds of Chinese herbal medicines showed relatively strong anti-lLTV effect, including Forsythia suspensa, Radix Isatidis, Fofium isatidis, Flos Ionicerae, Radix codonopsis, Radix astragali, Atractylodes, Radix gly- cyrrhizae, and Pericarpium granati. [Conclusion] The study laid the foundation for fur- ther development of Chinese herbal compound preparations to treat chicken cofibacil- Iosis, infectious laryngotracheitis and other bacterial, viral diseases.

Failure mechanism of Mesozoic soft rock roadway in Shajihai coal mine and its surrounding rock control

In view of the buckling failure caused by large deformation of Mesozoic soft rock roadway in Shajihai mining area, such as serious roof fall, rib spalling, floor heave, etc., based on the detail site investigation,theoretical analysis, mineral composition test, microstructure test, water-physical property test and field experiments were carried out. And we revealed the compound failure mechanism of Mesozoic soft rock roadway in Shajihai mining area, namely the molecule expansion-shear slip of weak structural plane-construction disturbance. On this basis, the coupling support technology whose core is constant resistance with large deformation bolt was proposed. The feature of this supporting technology is that a new type of structural composite material was used, which makes the supporting system not only has the ideal deformation characteristics, but also has high supporting resistance. Thus the fully release of plastic energy within surrounding rock and reasonable control of the thickness of the plastic ring were realized. Then the differential deformation between the surrounding rock and support was eliminated by the secondary coupling support of bolt–mesh–cable, and the bolt with high strength was applied in the base angle to control floor. Eventually the collaborative bearing system of surrounding rock–support was formed. Through field tests the validity and rationality of support was also verified.