RECREATING SMALL SEAMLESS TUBE MILLS BY PIERCING INSFEAD OF ROLLING     

Zhang Caian Mo Lilong Lu Zhiwen 《保鲜与加工》1992,(6):128-131

This paper discuss the effects of automatic plug mills in small seamless tube mills. Far from traditional ideas,the auther comes rp with mew ideas, which adot the mew process of replacing rolling by piercing,a huge sum of economical interests and great social benefits will be gained.  相似文献   

Experimental Research on High-strength Inorganic Anchoring Material     

PENG Xiao-qin  LIU Yan-meng  ZHONG An-xin  YANG Qiao 《保鲜与加工》2007,(2):113-115

A new type of inorganic anchoring material is developed as a substitution for anchoring adhesive to overcome some imperfections in the process of planting reinforcing steel bar.The mix proportion of the anchoring material is determined by experiments.The compressive strength,adhesive force to concrete,volume stability and anchoring force with steel bar are studied.The early strength of the anchoring inorganic material is quite high: for 1d up to 38.5MPa and 3d up to 60MPa.It is a good adhesive to concrete and the adhesive strength of 28d is about 2MPa.The anchoring material will have tiny volume expansion with the age,which is beneficial to enhancing the anchoring force.The essential component of the inorganic anchoring material is cement-based material,so some defects of the organic macromolecular material can be avoided,such as poor stability and requirement for vigorous construction conditions.Its characteristics in early strength,adhesive force to concrete and volume expansion can satisfy the requirement of the construction to the planting reinforcing steel bar and the loading force,thus it can be used as a substituting material for anchoring adhesive.  相似文献   

Determination of Pile-Soil Parameters for Steel Pipe Pile Subjected to Lateral Load     

《保鲜与加工》1997,(6):58-62

In this paper,in terms of the measured data(including the deflection and slope at the ground surface of the pile,the maximum bending moment and its position),the biparameter method is used to analyze the pile-soil parameters.Two examples show that the method in present paper is reasonable and reliable,and it provides the reference value for the engineering design.  相似文献   

Experimental Study on the Extended Length of Negative Reinforcement Cut-in Phases in Continuous Beams     

Zou Zhaowen  Fu Jianping  Bai Shaoliang 《保鲜与加工》1996,(2):10-19

In this paper through the static loading tests of 6 inflexion zones and 2 cantilever zones in full-size constrained R/C beams, the stress performance in rebars cut-in-phases and subjected to negative moment is studied. The stress properties of extended length of rebars with different shear-span ratiosare analysed on basis of the full measurement of strain distributions combined with the investigation on state and regularity of the diagonal cracks development and series of new knowledge are obtained. It is found that current Concrete Design Code provisions on the extended length are inadequate for the high shear-span ratio and superfluous for the low shear-span ratio. The theoretical and experimental foundations are provided for determining proper value of extended length for rebars cut-in-phases.  相似文献   

EFFECT OF HIGH LOADS IN THE BRIDGE LOAD SPECTRUM ON FATIGUE CRACK GROWTH OF 16 Mn STEEL     

Zhong An  Shen Xianrong 《保鲜与加工》1995,(2):15-22

This paper studies an effect of high loads in Rayleigh distribution random load-ing on fatigue crack growth wi th 16 Mn steel compact tenion specimen,The results show that thehigh loads in the load spectrum close to service load of steel bridges accelerate crack growth and re-duce crack growth life,Lives predicted with constant amplitude da/dn data and equivalent loads arequite in agreement with test lives.  相似文献   

Analysis of Load-bearing Characteristics of Concrete Pile Composite Foundation     

HU Zhi~  WANG Xian-neng~  HU Dai-wen~  DAI Jun~ 《保鲜与加工》2004,(3):46-50

Some conclusions were drawn from two groups of in-site tests on concrete pile composite foundations. In the tests, it was found that the pressure under the rigid loading slab is different, in which the pressure under the center of the slab is the less and under the edge of the slab is the biggest. The pile-soil stress ratio is not a constant; it increases with the adding of the load. Most of the pile-soil ratio vary from 9 to 13 in these tests and the load that the piles share can be more than seventy percent of the whole load. It was proved that the bearing capacity of the concrete pile composite foundation is high with a little settlement, so it will be used more and more in the future.  相似文献   

Recommendations on Shrinkage and Temperature Reinforcements in Concrete Slabs     

LI Lei 《保鲜与加工》2004,(4):45-50

The mechanism of shrinkage cracking is discussed with a simple member, which is fully restrained and subjected only to an axial restraining force caused by shrinkage, while a simple procedure is presented for the determination of the number and spacing of the cracks and the average crack width. With the simple model, some examples are shown to compare the provisions for minimum shrinkage and temperature reinforcement in GB 50010-2002 Code, ACI 318-02 Code and AS 3600-1988 Code. The results show that the provisions in GB 50010-2002 Code are too weak in comparison with the others. Finally, some recommendations are proposed.  相似文献   

Analysis of Moment Modulation with Simulated Concrete Frame under Vertical and Horizontal Load     

CHEN Ping-you~  JIAN Bin~ 《保鲜与加工》2004,(5):39-42

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CALCULATING SYSTEM FOR SECOND-ORDER EFFECT IN THE COLUMNS OF REINFORCED CONCRETE FRAMES     

Bai Shaoliang 《保鲜与加工》1989,(2)

This paper makes an analysis and comparison of the calculatingsystem for second-order effect in columns of reinforced concrete frames proposedby scholars at home and abroad,and the systems adopted by codes of manycountries.The focus is on explaining the conceptual error and deficiency in somemethods.After expounding the basic law of the second-order effect in framecolumns with different restraints,this paper suggests an improvement of thecalculating system for second-order effect in frame columns for China's DesignCode of Concrete Structures.  相似文献   

THE STUDY OF STRAIN FATIGUE CRACK PROPAGATION BEHAVOURS OF VANADIUM BEARING HSLA STEEL     

Sheng Guangmin Gong Shihong Zhu Jinfu 《保鲜与加工》1989,(2):67-72

In this paper, the strain fatigue: crack propagation rates of vanadium bearing HSLA steel with different micro-structures are measured under constant load conditions, and the relationship between the crack propagation rate and the microstructures of steel is also studied.  相似文献