A Comparative Study of Confined Concrete Models under Cyclic Loading

In this paper,four models are selected as the representatives and applied to nonlinear dynamic analysis program for space frames which is based on the beam-column elements using the finite element flexibility method and the fiber model.Park's test on combined axial and bending columns under cyclic loading are taken as the calibrations,comparisons to material and structural member level are drawn and the analytical results of various models are discussed.     

RECREATING SMALL SEAMLESS TUBE MILLS BY PIERCING INSFEAD OF ROLLING

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.     

Experimental Research on High-strength Inorganic Anchoring Material

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.     

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

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.     

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

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.     

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

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.     

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

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.     

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

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.